From 3e3e187f34d6780af40d0b4e6e2743a7ccbeb7ea Mon Sep 17 00:00:00 2001
From: Jason Smith <jason.inet@gmail.com>
Date: Sun, 20 Sep 2020 21:27:06 -0700
Subject: [PATCH 01/33] Update Malyan LCD to use MSerial on STM32F1, and try to
 prevent use of non-MSerial ports.

---
 Marlin/src/HAL/STM32F1/HAL.h                  |  84 ++++++------
 Marlin/src/HAL/STM32F1/MarlinSerial.cpp       | 129 +++++++++++++++---
 Marlin/src/HAL/STM32F1/MarlinSerial.h         |  19 ++-
 Marlin/src/lcd/extui/malyan_lcd.cpp           |  14 +-
 Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h |  10 +-
 .../pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h  |   8 +-
 .../pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h  |   8 +-
 Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h  |   8 +-
 Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h      |  16 +--
 .../pins/stm32f1/pins_MKS_ROBIN_E3_common.h   |   8 +-
 .../src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h |  16 +--
 Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h  |  17 +--
 12 files changed, 208 insertions(+), 129 deletions(-)

diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index f76d8c54a0e3..803fa0c4ef53 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -68,43 +68,36 @@
   #endif
 #endif
 
-#if SERIAL_PORT == 0
-  #error "SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-#elif SERIAL_PORT == -1
+#define _MSERIAL(X) MSerial##X
+#define MSERIAL(X) _MSERIAL(X)
+
+#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+  #define NUM_UARTS 5
+#else
+  #define NUM_UARTS 3
+#endif
+
+#if SERIAL_PORT == -1
   #define MYSERIAL0 UsbSerial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 MSerial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 MSerial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 MSerial3
-#elif SERIAL_PORT == 4
-  #define MYSERIAL0 MSerial4
-#elif SERIAL_PORT == 5
-  #define MYSERIAL0 MSerial5
+#elif WITHIN(SERIAL_PORT, 1, NUM_UARTS)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
+#elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+  #error "SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
 #else
-  #error "SERIAL_PORT must be from -1 to 5. Please update your configuration."
+  #error "SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == 0
-    #error "SERIAL_PORT_2 cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif SERIAL_PORT_2 == SERIAL_PORT
+  #if SERIAL_PORT_2 == SERIAL_PORT
     #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 UsbSerial
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 MSerial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 MSerial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 MSerial3
-  #elif SERIAL_PORT_2 == 4
-    #define MYSERIAL1 MSerial4
-  #elif SERIAL_PORT_2 == 5
-    #define MYSERIAL1 MSerial5
+  #elif WITHIN(SERIAL_PORT_2, 1, NUM_UARTS)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
+  #elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+    #error "SERIAL_PORT_2 must be -1 or from 1 to 5. Please update your configuration."
   #else
-    #error "SERIAL_PORT_2 must be from -1 to 5. Please update your configuration."
+    #error "SERIAL_PORT_2 must be -1 or from 1 to 3. Please update your configuration."
   #endif
   #define NUM_SERIAL 2
 #else
@@ -112,29 +105,36 @@
 #endif
 
 #ifdef DGUS_SERIAL
-  #if DGUS_SERIAL_PORT == 0
-    #error "DGUS_SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
+  #if DGUS_SERIAL_PORT == SERIAL_PORT
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
   #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #elif DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL UsbSerial
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL MSerial1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL MSerial2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL MSerial3
-  #elif DGUS_SERIAL_PORT == 4
-    #define DGUS_SERIAL MSerial4
-  #elif DGUS_SERIAL_PORT == 5
-    #define DGUS_SERIAL MSerial5
+  #elif WITHIN(DGUS_SERIAL_PORT, 1, NUM_UARTS)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
+  #elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+    #error "DGUS_SERIAL must be -1 or from 1 to 5. Please update your configuration."
   #else
-    #error "DGUS_SERIAL_PORT must be from -1 to 5. Please update your configuration."
+    #error "DGUS_SERIAL must be -1 or from 1 to 3. Please update your configuration."
   #endif
 #endif
 
+#ifdef MALYAN_LCD
+  #if MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
+    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && MALYAN_LCD_SERIAL_PORT == SERIAL_PORT_2
+    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
+  #elif defined(DGUS_SERIAL) && MALYAN_LCD_SERIAL_PORT == DGUS_SERIAL_PORT
+    #error "MALYAN_LCD_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
+  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, NUM_UARTS)
+    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_LCD_SERIAL_PORT)
+  #elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+    #error "MALYAN_LCD_SERIAL_PORT must be from 1 to 5. Please update your configuration."
+  #else
+    #error "MALYAN_LCD_SERIAL_PORT must be from 1 to 3. Please update your configuration."
+  #endif
+#endif
 
 // Set interrupt grouping for this MCU
 void HAL_init();
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
index 9a48e901f42d..c57fff81b656 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
@@ -22,7 +22,7 @@
 
 #ifdef __STM32F1__
 
-#include "../../inc/MarlinConfigPre.h"
+#include "../../inc/MarlinConfig.h"
 #include "MarlinSerial.h"
 #include <libmaple/usart.h>
 
@@ -53,7 +53,8 @@ static inline __always_inline void my_usart_irq(ring_buffer *rb, ring_buffer *wb
         rb_push_insert(rb, c);
       #endif
       #if ENABLED(EMERGENCY_PARSER)
-        emergency_parser.update(serial.emergency_state, c);
+        if (serial.emergency_parser_enabled)
+          emergency_parser.update(serial.emergency_state, c);
       #endif
     }
   }
@@ -73,40 +74,124 @@ static inline __always_inline void my_usart_irq(ring_buffer *rb, ring_buffer *wb
   }
 }
 
+// Not every MarlinSerial port should handle emergency parsing.
+// It would not make sense to parse GCode from TMC responses, for example.
+constexpr bool serial_handles_emergency(int port)
+{
+  return false
+    #ifdef SERIAL_PORT
+      || (SERIAL_PORT) == port
+    #endif
+    #ifdef SERIAL_PORT_2
+      || (SERIAL_PORT_2) == port
+    #endif
+    #ifdef DGUS_SERIAL_PORT 
+      || (DGUS_SERIAL_PORT) == port
+    #endif
+    ;
+}
+
 #define DEFINE_HWSERIAL_MARLIN(name, n)  \
   MarlinSerial name(USART##n,            \
             BOARD_USART##n##_TX_PIN,     \
-            BOARD_USART##n##_RX_PIN);    \
+            BOARD_USART##n##_RX_PIN,     \
+            serial_handles_emergency(n));\
   extern "C" void __irq_usart##n(void) { \
     my_usart_irq(USART##n->rb, USART##n->wb, USART##n##_BASE, MSerial##n); \
   }
 
 #define DEFINE_HWSERIAL_UART_MARLIN(name, n) \
-  MarlinSerial name(UART##n,                 \
-            BOARD_USART##n##_TX_PIN,         \
-            BOARD_USART##n##_RX_PIN);        \
-  extern "C" void __irq_usart##n(void) {     \
-    my_usart_irq(USART##n->rb, USART##n->wb, USART##n##_BASE, MSerial##n); \
-  }
+MarlinSerial name(UART##n,                 \
+          BOARD_USART##n##_TX_PIN,         \
+          BOARD_USART##n##_RX_PIN,         \
+          serial_handles_emergency(n));    \
+extern "C" void __irq_usart##n(void) {     \
+  my_usart_irq(UART##n->rb, UART##n->wb, UART##n##_BASE, MSerial##n); \
+}
 
-#if SERIAL_PORT == 1 || SERIAL_PORT_2 == 1 || DGUS_SERIAL_PORT == 1
-  DEFINE_HWSERIAL_MARLIN(MSerial1, 1);
+// Instantiate all UARTs even if they are not needed
+// This avoids a bunch of logic to figure out every serial
+// port which may be in use on the system.
+DEFINE_HWSERIAL_MARLIN(MSerial1, 1);
+DEFINE_HWSERIAL_MARLIN(MSerial2, 2);
+DEFINE_HWSERIAL_MARLIN(MSerial3, 3);
+#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+  DEFINE_HWSERIAL_UART_MARLIN(MSerial4, 4);
+  DEFINE_HWSERIAL_UART_MARLIN(MSerial5, 5);
 #endif
 
-#if SERIAL_PORT == 2 || SERIAL_PORT_2 == 2 || DGUS_SERIAL_PORT == 2
-  DEFINE_HWSERIAL_MARLIN(MSerial2, 2);
-#endif
+// Check the type of each serial port by passing it to a template function.
+// HardwareSerial is known to sometimes hang the controller when an error occurs,
+// so this case will fail the static assert. All other classes are assumed to be ok.
+template <typename T>
+constexpr bool IsSerialClassAllowed(const T&) { return true; }
+constexpr bool IsSerialClassAllowed(const HardwareSerial&) { return false; }
 
-#if SERIAL_PORT == 3 || SERIAL_PORT_2 == 3 || DGUS_SERIAL_PORT == 3
-  DEFINE_HWSERIAL_MARLIN(MSerial3, 3);
-#endif
+#define CHECK_CFG_SERIAL(A) static_assert(IsSerialClassAllowed(A), STRINGIFY(A) " is defined incorrectly");
+#define CHECK_AXIS_SERIAL(A) static_assert(IsSerialClassAllowed(A##_HARDWARE_SERIAL), STRINGIFY(A) "_HARDWARE_SERIAL must be defined in the form MSerial1, rather than Serial1");
 
-#if SERIAL_PORT == 4 || SERIAL_PORT_2 == 4 || DGUS_SERIAL_PORT == 4
-  DEFINE_HWSERIAL_UART_MARLIN(MSerial4, 4);
-#endif
+// If you encounter this error, replace SerialX with MSerialX, for example MSerial3.
 
-#if SERIAL_PORT == 5 || SERIAL_PORT_2 == 5 || DGUS_SERIAL_PORT == 5
-  DEFINE_HWSERIAL_UART_MARLIN(MSerial5, 5);
+// Non-TMC ports were already validated in HAL.h, so do not require verbose error messages.
+#ifdef MYSERIAL0
+  CHECK_CFG_SERIAL(MYSERIAL0);
+#endif
+#ifdef MYSERIAL1
+  CHECK_CFG_SERIAL(MYSERIAL1);
+#endif
+#ifdef DGUS_SERIAL
+  CHECK_CFG_SERIAL(DGUS_SERIAL);
+#endif
+#ifdef MALYAN_LCD_SERIAL
+  CHECK_CFG_SERIAL(MALYAN_LCD_SERIAL);
+#endif
+#if AXIS_HAS_HW_SERIAL(X)
+  CHECK_AXIS_SERIAL(X);
+#endif
+#if AXIS_HAS_HW_SERIAL(X2)
+  CHECK_AXIS_SERIAL(X2);
+#endif
+#if AXIS_HAS_HW_SERIAL(Y)
+  CHECK_AXIS_SERIAL(Y);
+#endif
+#if AXIS_HAS_HW_SERIAL(Y2)
+  CHECK_AXIS_SERIAL(Y2);
+#endif
+#if AXIS_HAS_HW_SERIAL(Z)
+  CHECK_AXIS_SERIAL(Z);
+#endif
+#if AXIS_HAS_HW_SERIAL(Z2)
+  CHECK_AXIS_SERIAL(Z2);
+#endif
+#if AXIS_HAS_HW_SERIAL(Z3)
+  CHECK_AXIS_SERIAL(Z3);
+#endif
+#if AXIS_HAS_HW_SERIAL(Z4)
+  CHECK_AXIS_SERIAL(Z4);
+#endif
+#if AXIS_HAS_HW_SERIAL(E0)
+  CHECK_AXIS_SERIAL(E0);
+#endif
+#if AXIS_HAS_HW_SERIAL(E1)
+  CHECK_AXIS_SERIAL(E1);
+#endif
+#if AXIS_HAS_HW_SERIAL(E2)
+  CHECK_AXIS_SERIAL(E2);
+#endif
+#if AXIS_HAS_HW_SERIAL(E3)
+  CHECK_AXIS_SERIAL(E3);
+#endif
+#if AXIS_HAS_HW_SERIAL(E4)
+  CHECK_AXIS_SERIAL(E4);
+#endif
+#if AXIS_HAS_HW_SERIAL(E5)
+  CHECK_AXIS_SERIAL(E5);
+#endif
+#if AXIS_HAS_HW_SERIAL(E6)
+  CHECK_AXIS_SERIAL(E6);
+#endif
+#if AXIS_HAS_HW_SERIAL(E7)
+  CHECK_AXIS_SERIAL(E7);
 #endif
 
 #endif // __STM32F1__
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index eb0059bfbcae..c99f5078cf79 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -30,16 +30,22 @@
   #include "../../feature/e_parser.h"
 #endif
 
+// Increase priority of serial interrupts, to reduce overflow errors
 #define UART_IRQ_PRIO 1
 
 class MarlinSerial : public HardwareSerial {
 public:
-  MarlinSerial(struct usart_dev *usart_device, uint8 tx_pin, uint8 rx_pin) :
+  MarlinSerial(struct usart_dev *usart_device, uint8 tx_pin, uint8 rx_pin, bool emergency_parser) :
     HardwareSerial(usart_device, tx_pin, rx_pin)
     #if ENABLED(EMERGENCY_PARSER)
-      , emergency_state(EmergencyParser::State::EP_RESET)
+      , emergency_parser_enabled(emergency_parser),
+      emergency_state(EmergencyParser::State::EP_RESET)
     #endif
-    { }
+    {
+      #if DISABLED(EMERGENCY_PARSER)
+        UNUSED(emergency_parser);
+      #endif
+    }
 
   #ifdef UART_IRQ_PRIO
     // shadow the parent methods to set irq priority after the begin
@@ -54,6 +60,7 @@ class MarlinSerial : public HardwareSerial {
   #endif
 
   #if ENABLED(EMERGENCY_PARSER)
+    bool emergency_parser_enabled;
     EmergencyParser::State emergency_state;
   #endif
 };
@@ -61,5 +68,7 @@ class MarlinSerial : public HardwareSerial {
 extern MarlinSerial MSerial1;
 extern MarlinSerial MSerial2;
 extern MarlinSerial MSerial3;
-extern MarlinSerial MSerial4;
-extern MarlinSerial MSerial5;
+#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+  extern MarlinSerial MSerial4;
+  extern MarlinSerial MSerial5;
+#endif
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index b5148065c7cc..7c4e8c05eec0 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -63,7 +63,9 @@
 
 // On the Malyan M200, this will be Serial1. On a RAMPS board,
 // it might not be.
-#define LCD_SERIAL Serial1
+#ifndef MALYAN_LCD_SERIAL
+  #error "Must define MALYAN_LCD_SERIAL to use MALYAN_LCD"
+#endif
 
 // This is based on longest sys command + a filename, plus some buffer
 // in case we encounter some data we don't recognize
@@ -84,7 +86,7 @@ void write_to_lcd_P(PGM_P const message) {
   LOOP_L_N(i, message_length)
     encoded_message[i] = pgm_read_byte(&message[i]) | 0x80;
 
-  LCD_SERIAL.Print::write(encoded_message, message_length);
+  MALYAN_LCD_SERIAL.Print::write(encoded_message, message_length);
 }
 
 void write_to_lcd(const char * const message) {
@@ -94,7 +96,7 @@ void write_to_lcd(const char * const message) {
   LOOP_L_N(i, message_length)
     encoded_message[i] = message[i] | 0x80;
 
-  LCD_SERIAL.Print::write(encoded_message, message_length);
+  MALYAN_LCD_SERIAL.Print::write(encoded_message, message_length);
 }
 
 // {E:<msg>} is for error states.
@@ -432,7 +434,7 @@ namespace ExtUI {
      * it and translate into ExtUI operations where possible.
      */
     inbound_count = 0;
-    LCD_SERIAL.begin(500000);
+    MALYAN_LCD_SERIAL.begin(500000);
 
     // Signal init
     write_to_lcd_P(PSTR("{SYS:STARTED}\r\n"));
@@ -455,8 +457,8 @@ namespace ExtUI {
     update_usb_status(false);
 
     // now drain commands...
-    while (LCD_SERIAL.available())
-      parse_lcd_byte((byte)LCD_SERIAL.read());
+    while (MALYAN_LCD_SERIAL.available())
+      parse_lcd_byte((byte)MALYAN_LCD_SERIAL.read());
 
     #if ENABLED(SDSUPPORT)
       // The way last printing status works is simple:
diff --git a/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h b/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
index cff34daf2f02..ebea752c7a4c 100644
--- a/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
+++ b/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
@@ -28,7 +28,7 @@
 #define BOARD_INFO_NAME "BTT SKR E3 DIP V1.0"
 
 // Release PB3/PB4 (TMC_SW Pins) from JTAG pins
-#define DISABLE_JTAG
+// #define DISABLE_JTAG
 
 // Ignore temp readings during development.
 //#define BOGUS_TEMPERATURE_GRACE_PERIOD    2000
@@ -117,10 +117,10 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial
diff --git a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h
index b658f3d714b8..78751a6bac87 100644
--- a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h
+++ b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h
@@ -30,8 +30,8 @@
  * Hardware serial communication ports.
  */
 #if HAS_TMC_UART
-  #define X_HARDWARE_SERIAL  Serial4
-  #define Y_HARDWARE_SERIAL  Serial4
-  #define Z_HARDWARE_SERIAL  Serial4
-  #define E0_HARDWARE_SERIAL Serial4
+  #define X_HARDWARE_SERIAL  MSerial4
+  #define Y_HARDWARE_SERIAL  MSerial4
+  #define Z_HARDWARE_SERIAL  MSerial4
+  #define E0_HARDWARE_SERIAL MSerial4
 #endif
diff --git a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h
index cb94f0bdcacd..0a0d857db3f4 100644
--- a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h
+++ b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h
@@ -52,8 +52,8 @@
  * Hardware serial communication ports.
  */
 #if HAS_TMC_UART
-  #define X_HARDWARE_SERIAL  Serial4
-  #define Y_HARDWARE_SERIAL  Serial4
-  #define Z_HARDWARE_SERIAL  Serial4
-  #define E0_HARDWARE_SERIAL Serial4
+  #define X_HARDWARE_SERIAL  MSerial4
+  #define Y_HARDWARE_SERIAL  MSerial4
+  #define Z_HARDWARE_SERIAL  MSerial4
+  #define E0_HARDWARE_SERIAL MSerial4
 #endif
diff --git a/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h b/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h
index ca9364a570d9..f8cbec1e26ac 100644
--- a/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h
+++ b/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h
@@ -93,10 +93,10 @@
   //
   // Hardware serial with switch
   //
-  #define X_HARDWARE_SERIAL  Serial1
-  #define Y_HARDWARE_SERIAL  Serial1
-  #define Z_HARDWARE_SERIAL  Serial1
-  #define E0_HARDWARE_SERIAL Serial1
+  #define X_HARDWARE_SERIAL  MSerial1
+  #define Y_HARDWARE_SERIAL  MSerial1
+  #define Z_HARDWARE_SERIAL  MSerial1
+  #define E0_HARDWARE_SERIAL MSerial1
 
   // The 4xTMC2209 module doesn't have a serial multiplexer and
   // needs to set *_SLAVE_ADDRESS in Configuration_adv.h for X,Y,Z,E0
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h
index 1ab9165830e0..ab6a125472d7 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h
@@ -188,17 +188,11 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define X2_HARDWARE_SERIAL Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Y2_HARDWARE_SERIAL Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define Z2_HARDWARE_SERIAL Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
-  //#define E1_HARDWARE_SERIAL Serial1
-  //#define E2_HARDWARE_SERIAL Serial1
-  //#define E3_HARDWARE_SERIAL Serial1
-  //#define E4_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
+  //#define E1_HARDWARE_SERIAL MSerial1
 
   // Unused servo pins may be repurposed with SoftwareSerialM
   //#define X_SERIAL_TX_PIN                 PF8   // SERVO3_PIN -- XS2 - 6
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h
index 9461a828af01..1bedb331fd53 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h
@@ -83,10 +83,10 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h
index d911ab2b517b..1732513af100 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h
@@ -132,17 +132,11 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define X2_HARDWARE_SERIAL Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Y2_HARDWARE_SERIAL Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define Z2_HARDWARE_SERIAL Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
-  //#define E1_HARDWARE_SERIAL Serial1
-  //#define E2_HARDWARE_SERIAL Serial1
-  //#define E3_HARDWARE_SERIAL Serial1
-  //#define E4_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
+  //#define E1_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h
index 9b3817df8c7b..7c09602442fe 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h
@@ -125,17 +125,12 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define X2_HARDWARE_SERIAL Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Y2_HARDWARE_SERIAL Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define Z2_HARDWARE_SERIAL Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
-  //#define E1_HARDWARE_SERIAL Serial1
-  //#define E2_HARDWARE_SERIAL Serial1
-  //#define E3_HARDWARE_SERIAL Serial1
-  //#define E4_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
+  //#define E1_HARDWARE_SERIAL MSerial1
+  //#define E2_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial

From 6a718b2a652dd251bce8cd20a36bcdc2758ba3b3 Mon Sep 17 00:00:00 2001
From: Jason Smith <jason.inet@gmail.com>
Date: Sun, 20 Sep 2020 22:25:57 -0700
Subject: [PATCH 02/33] Add Configuration.h option.

---
 Marlin/Configuration.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index 2635bc750eb0..14d4fa5355bf 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -2165,6 +2165,10 @@
 // Touch-screen LCD for Malyan M200/M300 printers
 //
 //#define MALYAN_LCD
+#if ENABLED(MALYAN_LCD)
+  // This will be 1 on a Malyan M200, but may differ on other boards.
+  #define MALYAN_LCD_SERIAL_PORT 1
+#endif
 
 //
 // Touch UI for FTDI EVE (FT800/FT810) displays

From d59c3d22ad92793aa77e69562f9ac1366c7864f2 Mon Sep 17 00:00:00 2001
From: Jason Smith <jason.inet@gmail.com>
Date: Mon, 21 Sep 2020 19:57:03 -0700
Subject: [PATCH 03/33] Allow compiling with STM32 HAL (for Malyan M200/M300)

---
 Marlin/src/HAL/STM32/HAL.h          | 81 ++++++++++++-----------------
 Marlin/src/HAL/STM32F1/HAL.h        |  4 +-
 Marlin/src/lcd/extui/malyan_lcd.cpp |  2 +-
 3 files changed, 37 insertions(+), 50 deletions(-)

diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index 08081331b736..a83135a45651 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -43,82 +43,67 @@
 // ------------------------
 // Defines
 // ------------------------
+#define _MSERIAL(X) MSerial##X
+#define MSERIAL(X) _MSERIAL(X)
 
-#if SERIAL_PORT == 0
-  #error "SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-#elif SERIAL_PORT == -1
+#if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 MSerial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 MSerial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 MSerial3
-#elif SERIAL_PORT == 4
-  #define MYSERIAL0 MSerial4
-#elif SERIAL_PORT == 5
-  #define MYSERIAL0 MSerial5
-#elif SERIAL_PORT == 6
-  #define MYSERIAL0 MSerial6
+#elif WITHIN(SERIAL_PORT, 1, 6)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
-  #error "SERIAL_PORT must be from -1 to 6. Please update your configuration."
+  #error "SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
 #endif
 
 #ifdef SERIAL_PORT_2
   #define NUM_SERIAL 2
-  #if SERIAL_PORT_2 == 0
-    #error "SERIAL_PORT_2 cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif SERIAL_PORT_2 == SERIAL_PORT
+  #if SERIAL_PORT_2 == SERIAL_PORT
     #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 MSerial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 MSerial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 MSerial3
-  #elif SERIAL_PORT_2 == 4
-    #define MYSERIAL1 MSerial4
-  #elif SERIAL_PORT_2 == 5
-    #define MYSERIAL1 MSerial5
-  #elif SERIAL_PORT_2 == 6
-    #define MYSERIAL1 MSerial6
+  #elif WITHIN(SERIAL_PORT, 1, 6)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
-    #error "SERIAL_PORT_2 must be from -1 to 6. Please update your configuration."
+    #error "SERIAL_PORT_2 must be -1 or from 1 to 6. Please update your configuration."
   #endif
 #else
   #define NUM_SERIAL 1
 #endif
 
+
 #if HAS_DGUS_LCD
-  #if DGUS_SERIAL_PORT == 0
-    #error "DGUS_SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
+  #if DGUS_SERIAL_PORT == SERIAL_PORT
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
   #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #elif DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL SerialUSB
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL MSerial1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL MSerial2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL MSerial3
-  #elif DGUS_SERIAL_PORT == 4
-    #define DGUS_SERIAL MSerial4
-  #elif DGUS_SERIAL_PORT == 5
-    #define DGUS_SERIAL MSerial5
-  #elif DGUS_SERIAL_PORT == 6
-    #define DGUS_SERIAL MSerial6
+  #elif WITHIN(DGUS_SERIAL_PORT, 1, 6)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
-    #error "DGUS_SERIAL_PORT must be from -1 to 6. Please update your configuration."
+    #error "DGUS_SERIAL must be -1 or from 1 to 6. Please update your configuration."
   #endif
 
   #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.availableForWrite
 #endif
 
+#ifdef MALYAN_LCD
+  #define _FRAMEWORK_SERIAL(X) Serial##X
+  #define FRAMEWORK_SERIAL(X) _FRAMEWORK_SERIAL(X)
+
+  #ifndef MALYAN_LCD_SERIAL_PORT
+    #error "MALYAN_LCD requires MALYAN_LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
+    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && MALYAN_LCD_SERIAL_PORT == SERIAL_PORT_2
+    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
+  #elif defined(DGUS_SERIAL) && MALYAN_LCD_SERIAL_PORT == DGUS_SERIAL_PORT
+    #error "MALYAN_LCD_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
+  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, 6)
+    #define MALYAN_LCD_SERIAL FRAMEWORK_SERIAL(MALYAN_LCD_SERIAL_PORT)
+  #else
+    #error "MALYAN_LCD_SERIAL_PORT must be from 1 to 6. Please update your configuration."
+  #endif
+#endif
 
 /**
  * TODO: review this to return 1 for pins that are not analog input
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index 803fa0c4ef53..c744839ad0ef 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -121,7 +121,9 @@
 #endif
 
 #ifdef MALYAN_LCD
-  #if MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
+  #ifndef MALYAN_LCD_SERIAL_PORT
+    #error "MALYAN_LCD requires MALYAN_LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
     #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
   #elif defined(SERIAL_PORT_2) && MALYAN_LCD_SERIAL_PORT == SERIAL_PORT_2
     #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index 7c4e8c05eec0..8293e6280f77 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -64,7 +64,7 @@
 // On the Malyan M200, this will be Serial1. On a RAMPS board,
 // it might not be.
 #ifndef MALYAN_LCD_SERIAL
-  #error "Must define MALYAN_LCD_SERIAL to use MALYAN_LCD"
+  #error "Must define MALYAN_LCD_SERIAL_PORT in Configuration.h to use MALYAN_LCD"
 #endif
 
 // This is based on longest sys command + a filename, plus some buffer

From 2b824e45e7663ae135dd944bfa6de136ac7a32cc Mon Sep 17 00:00:00 2001
From: Jason Smith <jason.inet@gmail.com>
Date: Mon, 21 Sep 2020 20:38:47 -0700
Subject: [PATCH 04/33] Fix minor issues impacting CI

---
 Marlin/src/HAL/STM32/HAL.h        | 2 +-
 buildroot/tests/malyan_M300-tests | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index a83135a45651..0c24fc984a3c 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -60,7 +60,7 @@
     #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
-  #elif WITHIN(SERIAL_PORT, 1, 6)
+  #elif WITHIN(SERIAL_PORT_2, 1, 6)
     #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be -1 or from 1 to 6. Please update your configuration."
diff --git a/buildroot/tests/malyan_M300-tests b/buildroot/tests/malyan_M300-tests
index ada60d558429..8b41114470eb 100755
--- a/buildroot/tests/malyan_M300-tests
+++ b/buildroot/tests/malyan_M300-tests
@@ -9,6 +9,7 @@ set -e
 restore_configs
 use_example_configs "delta/Malyan M300"
 opt_disable AUTO_BED_LEVELING_3POINT
+opt_set MALYAN_LCD_SERIAL_PORT 1
 exec_test $1 $2 "Malyan M300 (delta)"
 
 # cleanup

From 343215043214c52fca7e90329372f5dd8eb04340 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 16:57:49 -0500
Subject: [PATCH 05/33] Macros for other serial port defines

---
 Marlin/src/HAL/AVR/HAL.h         |  6 +---
 Marlin/src/HAL/DUE/HAL.h         | 34 ++++++---------------
 Marlin/src/HAL/LPC1768/HAL.h     | 34 ++++++---------------
 Marlin/src/HAL/SAMD51/HAL.h      | 33 ++++++--------------
 Marlin/src/HAL/STM32_F4_F7/HAL.h | 52 ++++++--------------------------
 Marlin/src/HAL/TEENSY31_32/HAL.h | 14 ++++-----
 Marlin/src/HAL/TEENSY35_36/HAL.h | 14 ++++-----
 Marlin/src/HAL/TEENSY40_41/HAL.h | 44 +++++----------------------
 8 files changed, 60 insertions(+), 171 deletions(-)

diff --git a/Marlin/src/HAL/AVR/HAL.h b/Marlin/src/HAL/AVR/HAL.h
index 609375e386e8..9db3c22617b6 100644
--- a/Marlin/src/HAL/AVR/HAL.h
+++ b/Marlin/src/HAL/AVR/HAL.h
@@ -81,11 +81,7 @@ typedef int8_t pin_t;
 
 // Serial ports
 #ifdef USBCON
-  #if ENABLED(BLUETOOTH)
-    #define MYSERIAL0 bluetoothSerial
-  #else
-    #define MYSERIAL0 Serial
-  #endif
+  #define MYSERIAL0 TERN(BLUETOOTH, bluetoothSerial, Serial)
   #define NUM_SERIAL 1
 #else
   #if !WITHIN(SERIAL_PORT, -1, 3)
diff --git a/Marlin/src/HAL/DUE/HAL.h b/Marlin/src/HAL/DUE/HAL.h
index 31409c76dd56..9b20b7363ac4 100644
--- a/Marlin/src/HAL/DUE/HAL.h
+++ b/Marlin/src/HAL/DUE/HAL.h
@@ -38,17 +38,15 @@
 
 #include <stdint.h>
 
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
+
 // Define MYSERIAL0/1 before MarlinSerial includes!
 #if SERIAL_PORT == -1 || ENABLED(EMERGENCY_PARSER)
   #define MYSERIAL0 customizedSerial1
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "The required SERIAL_PORT must be from -1 to 3. Please update your configuration."
 #endif
@@ -58,14 +56,8 @@
     #error "SERIAL_PORT_2 must be different from SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1 || ENABLED(EMERGENCY_PARSER)
     #define MYSERIAL1 customizedSerial2
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 Serial
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 Serial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 Serial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 Serial3
+  #elif WITHIN(SERIAL_PORT_2, 0, 3)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
   #endif
@@ -81,14 +73,8 @@
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #elif DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL internalDgusSerial
-  #elif DGUS_SERIAL_PORT == 0
-    #define DGUS_SERIAL Serial
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL Serial1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL Serial2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL Serial3
+  #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
     #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index 0153bacf42dd..7ddad121ae4a 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -63,16 +63,14 @@ extern "C" volatile uint32_t _millis;
   #define ST7920_DELAY_3 DELAY_NS(750)
 #endif
 
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define MSerial0 MSerial
+
 #if SERIAL_PORT == -1
   #define MYSERIAL0 UsbSerial
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 MSerial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 MSerial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 MSerial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 MSerial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
 #endif
@@ -82,14 +80,8 @@ extern "C" volatile uint32_t _millis;
     #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 UsbSerial
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 MSerial
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 MSerial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 MSerial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 MSerial3
+  #elif WITHIN(SERIAL_PORT_2, 0, 3)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
   #endif
@@ -105,14 +97,8 @@ extern "C" volatile uint32_t _millis;
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #elif DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL UsbSerial
-  #elif DGUS_SERIAL_PORT == 0
-    #define DGUS_SERIAL MSerial
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL MSerial1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL MSerial2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL MSerial3
+  #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
     #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index ea0f694cdc02..7b1b693eadcb 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -35,16 +35,13 @@
 
   // MYSERIAL0 required before MarlinSerial includes!
 
+  #define _MSERIAL(X) Serial##X
+  #define MSERIAL(X) _MSERIAL(INCREMENT(X))
+
   #if SERIAL_PORT == -1
     #define MYSERIAL0 Serial
-  #elif SERIAL_PORT == 0
-    #define MYSERIAL0 Serial1
-  #elif SERIAL_PORT == 1
-    #define MYSERIAL0 Serial2
-  #elif SERIAL_PORT == 2
-    #define MYSERIAL0 Serial3
-  #elif SERIAL_PORT == 3
-    #define MYSERIAL0 Serial4
+  #elif WITHIN(SERIAL_PORT, 0, 3)
+    #define MYSERIAL0 MSERIAL(SERIAL_PORT)
   #else
     #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
@@ -54,14 +51,8 @@
       #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
     #elif SERIAL_PORT_2 == -1
       #define MYSERIAL1 Serial
-    #elif SERIAL_PORT_2 == 0
-      #define MYSERIAL1 Serial1
-    #elif SERIAL_PORT_2 == 1
-      #define MYSERIAL1 Serial2
-    #elif SERIAL_PORT_2 == 2
-      #define MYSERIAL1 Serial3
-    #elif SERIAL_PORT_2 == 3
-      #define MYSERIAL1 Serial4
+    #elif WITHIN(SERIAL_PORT_2, 0, 3)
+      #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
     #else
       #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
     #endif
@@ -77,14 +68,8 @@
       #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
     #elif DGUS_SERIAL_PORT == -1
       #define DGUS_SERIAL Serial
-    #elif DGUS_SERIAL_PORT == 0
-      #define DGUS_SERIAL Serial1
-    #elif DGUS_SERIAL_PORT == 1
-      #define DGUS_SERIAL Serial2
-    #elif DGUS_SERIAL_PORT == 2
-      #define DGUS_SERIAL Serial3
-    #elif DGUS_SERIAL_PORT == 2
-      #define DGUS_SERIAL Serial4
+    #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
+      #define MYSERIAL0 MSERIAL(DGUS_SERIAL_PORT)
     #else
       #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
     #endif
diff --git a/Marlin/src/HAL/STM32_F4_F7/HAL.h b/Marlin/src/HAL/STM32_F4_F7/HAL.h
index 5601400c5ac9..0f686c1c853e 100644
--- a/Marlin/src/HAL/STM32_F4_F7/HAL.h
+++ b/Marlin/src/HAL/STM32_F4_F7/HAL.h
@@ -46,24 +46,16 @@
 // Serial override
 //extern HalSerial usb_serial;
 
+#define _MSERIAL(X) SerialUART##X
+#define MSERIAL(X) _MSERIAL(X)
+#define SerialUART0 Serial1
+
 #if defined(STM32F4) && SERIAL_PORT == 0
   #error "SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
 #elif SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 SerialUART1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 SerialUART2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 SerialUART3
-#elif SERIAL_PORT == 4
-  #define MYSERIAL0 SerialUART4
-#elif SERIAL_PORT == 5
-  #define MYSERIAL0 SerialUART5
-#elif SERIAL_PORT == 6
-  #define MYSERIAL0 SerialUART6
+#elif WITHIN(SERIAL_PORT, 0, 6)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "SERIAL_PORT must be from -1 to 6. Please update your configuration."
 #endif
@@ -75,20 +67,8 @@
     #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 Serial1
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 SerialUART1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 SerialUART2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 SerialUART3
-  #elif SERIAL_PORT_2 == 4
-    #define MYSERIAL1 SerialUART4
-  #elif SERIAL_PORT_2 == 5
-    #define MYSERIAL1 SerialUART5
-  #elif SERIAL_PORT_2 == 6
-    #define MYSERIAL1 SerialUART6
+  #elif WITHIN(SERIAL_PORT_2, 0, 6)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be from -1 to 6. Please update your configuration."
   #endif
@@ -106,20 +86,8 @@
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #elif DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL SerialUSB
-  #elif DGUS_SERIAL_PORT == 0
-    #define DGUS_SERIAL Serial1
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL SerialUART1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL SerialUART2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL SerialUART3
-  #elif DGUS_SERIAL_PORT == 4
-    #define DGUS_SERIAL SerialUART4
-  #elif DGUS_SERIAL_PORT == 5
-    #define DGUS_SERIAL SerialUART5
-  #elif DGUS_SERIAL_PORT == 6
-    #define DGUS_SERIAL SerialUART6
+  #elif WITHIN(DGUS_SERIAL_PORT, 0, 6)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
     #error "DGUS_SERIAL_PORT must be from -1 to 6. Please update your configuration."
   #endif
diff --git a/Marlin/src/HAL/TEENSY31_32/HAL.h b/Marlin/src/HAL/TEENSY31_32/HAL.h
index ad095cba83cc..737579b25cc3 100644
--- a/Marlin/src/HAL/TEENSY31_32/HAL.h
+++ b/Marlin/src/HAL/TEENSY31_32/HAL.h
@@ -51,16 +51,14 @@
 
 #define NUM_SERIAL 1
 
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
+
 #if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #endif
 
 #define HAL_SERVO_LIB libServo
diff --git a/Marlin/src/HAL/TEENSY35_36/HAL.h b/Marlin/src/HAL/TEENSY35_36/HAL.h
index 96be08d7b7ca..75541d6f2a66 100644
--- a/Marlin/src/HAL/TEENSY35_36/HAL.h
+++ b/Marlin/src/HAL/TEENSY35_36/HAL.h
@@ -56,16 +56,14 @@
 
 #define NUM_SERIAL 1
 
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
+
 #if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #endif
 
 #define HAL_SERVO_LIB libServo
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index 0626d4ee9cda..2e0a7c049787 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -50,26 +50,14 @@
   #define IS_TEENSY41 1
 #endif
 
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
+
 #if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
-#elif SERIAL_PORT == 4
-  #define MYSERIAL0 Serial4
-#elif SERIAL_PORT == 5
-  #define MYSERIAL0 Serial5
-#elif SERIAL_PORT == 6
-  #define MYSERIAL0 Serial6
-#elif SERIAL_PORT == 7
-  #define MYSERIAL0 Serial7
-#elif SERIAL_PORT == 8
-  #define MYSERIAL0 Serial8
+#elif WITHIN(SERIAL_PORT, 0, 8)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "The required SERIAL_PORT must be from -1 to 8. Please update your configuration."
 #endif
@@ -79,24 +67,8 @@
     #error "SERIAL_PORT_2 must be different from SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 usbSerial
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 Serial
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 Serial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 Serial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 Serial3
-  #elif SERIAL_PORT_2 == 4
-    #define MYSERIAL1 Serial4
-  #elif SERIAL_PORT_2 == 5
-    #define MYSERIAL1 Serial5
-  #elif SERIAL_PORT_2 == 6
-    #define MYSERIAL1 Serial6
-  #elif SERIAL_PORT_2 == 7
-    #define MYSERIAL1 Serial7
-  #elif SERIAL_PORT_2 == 8
-    #define MYSERIAL1 Serial8
+  #elif WITHIN(SERIAL_PORT_2, 0, 8)
+    #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
   #else
       #error "SERIAL_PORT_2 must be from -1 to 8. Please update your configuration."
   #endif

From 60a7c2146dd2dd71b95a2f4c90fef25d78a67690 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 17:06:02 -0500
Subject: [PATCH 06/33] tweak option name

---
 Marlin/Configuration.h              |  2 +-
 Marlin/src/HAL/STM32/HAL.h          | 22 +++++++++++-----------
 Marlin/src/HAL/STM32F1/HAL.h        | 24 ++++++++++++------------
 Marlin/src/lcd/extui/malyan_lcd.cpp |  2 +-
 buildroot/tests/malyan_M300-tests   |  2 +-
 5 files changed, 26 insertions(+), 26 deletions(-)

diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index 14d4fa5355bf..ce767c7b0a85 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -2167,7 +2167,7 @@
 //#define MALYAN_LCD
 #if ENABLED(MALYAN_LCD)
   // This will be 1 on a Malyan M200, but may differ on other boards.
-  #define MALYAN_LCD_SERIAL_PORT 1
+  #define MALYAN_SERIAL_PORT 1
 #endif
 
 //
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index 0c24fc984a3c..c9da8c137192 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -90,18 +90,18 @@
   #define _FRAMEWORK_SERIAL(X) Serial##X
   #define FRAMEWORK_SERIAL(X) _FRAMEWORK_SERIAL(X)
 
-  #ifndef MALYAN_LCD_SERIAL_PORT
-    #error "MALYAN_LCD requires MALYAN_LCD_SERIAL_PORT to be defined in Configuration.h"
-  #elif MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
-    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && MALYAN_LCD_SERIAL_PORT == SERIAL_PORT_2
-    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif defined(DGUS_SERIAL) && MALYAN_LCD_SERIAL_PORT == DGUS_SERIAL_PORT
-    #error "MALYAN_LCD_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
-  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, 6)
-    #define MALYAN_LCD_SERIAL FRAMEWORK_SERIAL(MALYAN_LCD_SERIAL_PORT)
+  #ifndef MALYAN_SERIAL_PORT
+    #error "MALYAN_LCD requires MALYAN_SERIAL_PORT to be defined in Configuration.h"
+  #elif MALYAN_SERIAL_PORT == SERIAL_PORT
+    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && MALYAN_SERIAL_PORT == SERIAL_PORT_2
+    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
+  #elif defined(DGUS_SERIAL) && MALYAN_SERIAL_PORT == DGUS_SERIAL_PORT
+    #error "MALYAN_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
+  #elif WITHIN(MALYAN_SERIAL_PORT, 1, 6)
+    #define MALYAN_LCD_SERIAL FRAMEWORK_SERIAL(MALYAN_SERIAL_PORT)
   #else
-    #error "MALYAN_LCD_SERIAL_PORT must be from 1 to 6. Please update your configuration."
+    #error "MALYAN_SERIAL_PORT must be from 1 to 6. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index c744839ad0ef..273823001ea6 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -121,20 +121,20 @@
 #endif
 
 #ifdef MALYAN_LCD
-  #ifndef MALYAN_LCD_SERIAL_PORT
-    #error "MALYAN_LCD requires MALYAN_LCD_SERIAL_PORT to be defined in Configuration.h"
-  #elif MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
-    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && MALYAN_LCD_SERIAL_PORT == SERIAL_PORT_2
-    #error "MALYAN_LCD_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif defined(DGUS_SERIAL) && MALYAN_LCD_SERIAL_PORT == DGUS_SERIAL_PORT
-    #error "MALYAN_LCD_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
-  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, NUM_UARTS)
-    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_LCD_SERIAL_PORT)
   #elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
-    #error "MALYAN_LCD_SERIAL_PORT must be from 1 to 5. Please update your configuration."
+  #ifndef MALYAN_SERIAL_PORT
+    #error "MALYAN_LCD requires MALYAN_SERIAL_PORT to be defined in Configuration.h"
+  #elif MALYAN_SERIAL_PORT == SERIAL_PORT
+    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && MALYAN_SERIAL_PORT == SERIAL_PORT_2
+    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
+  #elif defined(DGUS_SERIAL) && MALYAN_SERIAL_PORT == DGUS_SERIAL_PORT
+    #error "MALYAN_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
+  #elif WITHIN(MALYAN_SERIAL_PORT, 1, NUM_UARTS)
+    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_SERIAL_PORT)
+    #error "MALYAN_SERIAL_PORT must be from 1 to 5. Please update your configuration."
   #else
-    #error "MALYAN_LCD_SERIAL_PORT must be from 1 to 3. Please update your configuration."
+    #error "MALYAN_SERIAL_PORT must be from 1 to 3. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index 8293e6280f77..32833f2a547f 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -64,7 +64,7 @@
 // On the Malyan M200, this will be Serial1. On a RAMPS board,
 // it might not be.
 #ifndef MALYAN_LCD_SERIAL
-  #error "Must define MALYAN_LCD_SERIAL_PORT in Configuration.h to use MALYAN_LCD"
+  #error "Must define MALYAN_SERIAL_PORT in Configuration.h to use MALYAN_LCD"
 #endif
 
 // This is based on longest sys command + a filename, plus some buffer
diff --git a/buildroot/tests/malyan_M300-tests b/buildroot/tests/malyan_M300-tests
index 8b41114470eb..06c08d3a6c98 100755
--- a/buildroot/tests/malyan_M300-tests
+++ b/buildroot/tests/malyan_M300-tests
@@ -9,7 +9,7 @@ set -e
 restore_configs
 use_example_configs "delta/Malyan M300"
 opt_disable AUTO_BED_LEVELING_3POINT
-opt_set MALYAN_LCD_SERIAL_PORT 1
+opt_set MALYAN_SERIAL_PORT 1
 exec_test $1 $2 "Malyan M300 (delta)"
 
 # cleanup

From d7986fa310be61844e44d2a40a343920f22eeba3 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 17:39:07 -0500
Subject: [PATCH 07/33] Misc fixes, adjustments

---
 Marlin/src/HAL/LPC1768/MarlinSerial.cpp       |  2 +-
 Marlin/src/HAL/LPC1768/inc/SanityCheck.h      | 36 ++++++++++++-------
 Marlin/src/HAL/STM32/HAL.h                    |  4 +--
 Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h |  2 +-
 Marlin/src/HAL/STM32F1/HAL.h                  | 20 +++++------
 Marlin/src/HAL/STM32F1/MarlinSerial.cpp       | 23 ++++++------
 Marlin/src/HAL/STM32F1/MarlinSerial.h         |  2 +-
 Marlin/src/HAL/STM32F1/sdio.cpp               |  2 +-
 Marlin/src/core/macros.h                      |  6 ++++
 Marlin/src/inc/SanityCheck.h                  |  2 +-
 10 files changed, 57 insertions(+), 42 deletions(-)

diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
index c3fb3bd0e4d2..6df5147e34da 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
@@ -24,7 +24,7 @@
 #include "../../inc/MarlinConfigPre.h"
 #include "MarlinSerial.h"
 
-#if (defined(SERIAL_PORT) && SERIAL_PORT == 0) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == 0) || (defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT == 0)
+#if ANY_ZERO(SERIAL_PORT, SERIAL_PORT_2, DGUS_SERIAL_PORT)
   MarlinSerial MSerial(LPC_UART0);
   extern "C" void UART0_IRQHandler() {
     MSerial.IRQHandler();
diff --git a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
index 3fc1dd801a45..350a46b44312 100644
--- a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
+++ b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
@@ -89,7 +89,10 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
  * Serial2 | P0_10 | P0_11 |
  * Serial3 | P0_00 | P0_01 |
  */
-#if (defined(SERIAL_PORT) && SERIAL_PORT == 0) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == 0) || (defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT == 0)
+#define ANY_TX(N,V...) DO(IS_TX##N,||,V)
+#define ANY_RX(N,V...) DO(IS_RX##N,||,V)
+
+#if ANY_ZERO(SERIAL_PORT, SERIAL_PORT_2, DGUS_SERIAL_PORT)
   #define IS_TX0(P) (P == P0_02)
   #define IS_RX0(P) (P == P0_03)
   #if IS_TX0(TMC_SW_MISO) || IS_RX0(TMC_SW_MOSI)
@@ -106,48 +109,56 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
 #if SERIAL_PORT == 1 || SERIAL_PORT_2 == 1 || DGUS_SERIAL_PORT == 1
   #define IS_TX1(P) (P == P0_15)
   #define IS_RX1(P) (P == P0_16)
+  #define _IS_TX1_1 IS_TX1
+  #define _IS_RX1_1 IS_RX1
   #if IS_TX1(TMC_SW_SCK)
     #error "Serial port pins (1) conflict with other pins!"
   #elif HAS_SPI_LCD
     #if IS_TX1(BTN_EN2) || IS_RX1(BTN_EN1)
       #error "Serial port pins (1) conflict with Encoder Buttons!"
-    #elif IS_TX1(SCK_PIN) || IS_TX1(LCD_PINS_D4) || IS_TX1(DOGLCD_SCK) || IS_TX1(LCD_RESET_PIN) || IS_TX1(LCD_PINS_RS) || IS_TX1(SHIFT_CLK) \
-      || IS_RX1(LCD_SDSS) || IS_RX1(LCD_PINS_RS) || IS_RX1(MISO_PIN) || IS_RX1(DOGLCD_A0) || IS_RX1(SS_PIN) || IS_RX1(LCD_SDSS) || IS_RX1(DOGLCD_CS) || IS_RX1(LCD_RESET_PIN) || IS_RX1(LCD_BACKLIGHT_PIN)
+    #elif ANY_TX(1, SCK_PIN, LCD_PINS_D4, DOGLCD_SCK, LCD_RESET_PIN, LCD_PINS_RS, SHIFT_CLK) \
+       || ANY_RX(1, LCD_SDSS, LCD_PINS_RS, MISO_PIN, DOGLCD_A0, SS_PIN, LCD_SDSS, DOGLCD_CS, LCD_RESET_PIN, LCD_BACKLIGHT_PIN)
       #error "Serial port pins (1) conflict with LCD pins!"
     #endif
   #endif
   #undef IS_TX1
   #undef IS_RX1
+  #undef _IS_TX1_1
+  #undef _IS_RX1_1
 #endif
 
 #if SERIAL_PORT == 2 || SERIAL_PORT_2 == 2 || DGUS_SERIAL_PORT == 2
   #define IS_TX2(P) (P == P0_10)
   #define IS_RX2(P) (P == P0_11)
-  #if  IS_TX2(X2_ENABLE_PIN) || IS_RX2(X2_DIR_PIN) || IS_RX2(X2_STEP_PIN) || (AXIS_HAS_SPI(X2) && IS_TX2(X2_CS_PIN))
+  #define _IS_TX2_1 IS_TX2
+  #define _IS_RX2_1 IS_RX2
+  #if IS_TX2(X2_ENABLE_PIN) || ANY_RX2(X2_DIR_PIN, X2_STEP_PIN) || (AXIS_HAS_SPI(X2) && IS_TX2(X2_CS_PIN))
     #error "Serial port pins (2) conflict with X2 pins!"
-  #elif IS_TX2(Y2_ENABLE_PIN) || IS_RX2(Y2_DIR_PIN) || IS_RX2(Y2_STEP_PIN) || (AXIS_HAS_SPI(Y2) && IS_TX2(Y2_CS_PIN))
+  #elif IS_TX2(Y2_ENABLE_PIN) || ANY_RX2(Y2_DIR_PIN, Y2_STEP_PIN) || (AXIS_HAS_SPI(Y2) && IS_TX2(Y2_CS_PIN))
     #error "Serial port pins (2) conflict with Y2 pins!"
-  #elif IS_TX2(Z2_ENABLE_PIN) || IS_RX2(Z2_DIR_PIN) || IS_RX2(Z2_STEP_PIN) || (AXIS_HAS_SPI(Z2) && IS_TX2(Z2_CS_PIN))
+  #elif IS_TX2(Z2_ENABLE_PIN) || ANY_RX2(Z2_DIR_PIN, Z2_STEP_PIN) || (AXIS_HAS_SPI(Z2) && IS_TX2(Z2_CS_PIN))
     #error "Serial port pins (2) conflict with Z2 pins!"
-  #elif IS_TX2(Z3_ENABLE_PIN) || IS_RX2(Z3_DIR_PIN) || IS_RX2(Z3_STEP_PIN) || (AXIS_HAS_SPI(Z3) && IS_TX2(Z3_CS_PIN))
+  #elif IS_TX2(Z3_ENABLE_PIN) || ANY_RX2(Z3_DIR_PIN, Z3_STEP_PIN) || (AXIS_HAS_SPI(Z3) && IS_TX2(Z3_CS_PIN))
     #error "Serial port pins (2) conflict with Z3 pins!"
-  #elif IS_TX2(Z4_ENABLE_PIN) || IS_RX2(Z4_DIR_PIN) || IS_RX2(Z4_STEP_PIN) || (AXIS_HAS_SPI(Z4) && IS_TX2(Z4_CS_PIN))
+  #elif IS_TX2(Z4_ENABLE_PIN) || ANY_RX2(Z4_DIR_PIN, Z4_STEP_PIN) || (AXIS_HAS_SPI(Z4) && IS_TX2(Z4_CS_PIN))
     #error "Serial port pins (2) conflict with Z4 pins!"
-  #elif IS_RX2(X_DIR_PIN) || IS_RX2(Y_DIR_PIN)
+  #elif ANY_RX2(X_DIR_PIN, Y_DIR_PIN)
     #error "Serial port pins (2) conflict with other pins!"
   #elif Y_HOME_DIR < 0 && IS_TX2(Y_STOP_PIN)
     #error "Serial port pins (2) conflict with Y endstop pin!"
   #elif HAS_CUSTOM_PROBE_PIN && IS_TX2(Z_MIN_PROBE_PIN)
     #error "Serial port pins (2) conflict with probe pin!"
-  #elif IS_TX2(X_ENABLE_PIN) || IS_RX2(X_DIR_PIN) || IS_TX2(Y_ENABLE_PIN) || IS_RX2(Y_DIR_PIN)
+  #elif ANY_TX2(X_ENABLE_PIN, Y_ENABLE_PIN) || ANY_RX2(X_DIR_PIN, Y_DIR_PIN)
     #error "Serial port pins (2) conflict with X/Y stepper pins!"
   #elif HAS_MULTI_EXTRUDER && (IS_TX2(E1_ENABLE_PIN) || (AXIS_HAS_SPI(E1) && IS_TX2(E1_CS_PIN)))
     #error "Serial port pins (2) conflict with E1 stepper pins!"
-  #elif EXTRUDERS && (IS_RX2(E0_DIR_PIN) || IS_RX2(E0_STEP_PIN))
+  #elif EXTRUDERS && ANY_RX2(E0_DIR_PIN, E0_STEP_PIN)
     #error "Serial port pins (2) conflict with E stepper pins!"
   #endif
   #undef IS_TX2
   #undef IS_RX2
+  #undef _IS_TX2_1
+  #undef _IS_RX2_1
 #endif
 
 #if SERIAL_PORT == 3 || SERIAL_PORT_2 == 3 || DGUS_SERIAL_PORT == 3
@@ -155,8 +166,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #define PIN_IS_RX3(P) (P##_PIN == P0_01)
   #if PIN_IS_TX3(X_MIN) || PIN_IS_RX3(X_MAX)
     #error "Serial port pins (3) conflict with X endstop pins!"
-  #elif PIN_IS_TX3(Y_SERIAL_TX) || PIN_IS_TX3(Y_SERIAL_RX) \
-    ||  PIN_IS_RX3(X_SERIAL_TX) || PIN_IS_RX3(X_SERIAL_RX)
+  #elif PIN_IS_TX3(Y_SERIAL_TX) || PIN_IS_TX3(Y_SERIAL_RX) || PIN_IS_RX3(X_SERIAL_TX) || PIN_IS_RX3(X_SERIAL_RX)
     #error "Serial port pins (3) conflict with X/Y axis UART pins!"
   #elif PIN_IS_TX3(X2_DIR) || PIN_IS_RX3(X2_STEP)
     #error "Serial port pins (3) conflict with X2 pins!"
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index c9da8c137192..46a538118ace 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -80,13 +80,13 @@
   #elif WITHIN(DGUS_SERIAL_PORT, 1, 6)
     #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
-    #error "DGUS_SERIAL must be -1 or from 1 to 6. Please update your configuration."
+    #error "DGUS_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
   #endif
 
   #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.availableForWrite
 #endif
 
-#ifdef MALYAN_LCD
+#if ENABLED(MALYAN_LCD)
   #define _FRAMEWORK_SERIAL(X) Serial##X
   #define FRAMEWORK_SERIAL(X) _FRAMEWORK_SERIAL(X)
 
diff --git a/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h b/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h
index 5ff40debea5e..9069d9f7bd8a 100644
--- a/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h
+++ b/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h
@@ -98,7 +98,7 @@ static inline void pwm_details(const pin_t pin) {
     timer_dev * const tdev = PIN_MAP[pin].timer_device;
     const uint8_t channel = PIN_MAP[pin].timer_channel;
     const char num = (
-      #if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+      #if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
         tdev == &timer8 ? '8' :
         tdev == &timer5 ? '5' :
       #endif
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index 273823001ea6..6c9d98c4e7d5 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -53,7 +53,7 @@
 // ------------------------
 
 #ifndef STM32_FLASH_SIZE
-  #if defined(MCU_STM32F103RE) || defined(MCU_STM32F103VE)
+  #if EITHER(MCU_STM32F103RE, MCU_STM32F103VE)
     #define STM32_FLASH_SIZE 512
   #else
     #define STM32_FLASH_SIZE 256
@@ -71,7 +71,7 @@
 #define _MSERIAL(X) MSerial##X
 #define MSERIAL(X) _MSERIAL(X)
 
-#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+#if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
   #define NUM_UARTS 5
 #else
   #define NUM_UARTS 3
@@ -81,7 +81,7 @@
   #define MYSERIAL0 UsbSerial
 #elif WITHIN(SERIAL_PORT, 1, NUM_UARTS)
   #define MYSERIAL0 MSERIAL(SERIAL_PORT)
-#elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+#elif NUM_UARTS == 5
   #error "SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
 #else
   #error "SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
@@ -94,7 +94,7 @@
     #define MYSERIAL1 UsbSerial
   #elif WITHIN(SERIAL_PORT_2, 1, NUM_UARTS)
     #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
-  #elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+  #elif NUM_UARTS == 5
     #error "SERIAL_PORT_2 must be -1 or from 1 to 5. Please update your configuration."
   #else
     #error "SERIAL_PORT_2 must be -1 or from 1 to 3. Please update your configuration."
@@ -104,7 +104,7 @@
   #define NUM_SERIAL 1
 #endif
 
-#ifdef DGUS_SERIAL
+#ifdef DGUS_SERIAL_PORT
   #if DGUS_SERIAL_PORT == SERIAL_PORT
     #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
   #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
@@ -113,15 +113,14 @@
     #define DGUS_SERIAL UsbSerial
   #elif WITHIN(DGUS_SERIAL_PORT, 1, NUM_UARTS)
     #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
-  #elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
-    #error "DGUS_SERIAL must be -1 or from 1 to 5. Please update your configuration."
+  #elif NUM_UARTS == 5
+    #error "DGUS_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
   #else
-    #error "DGUS_SERIAL must be -1 or from 1 to 3. Please update your configuration."
+    #error "DGUS_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
   #endif
 #endif
 
-#ifdef MALYAN_LCD
-  #elif defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+#if ENABLED(MALYAN_LCD)
   #ifndef MALYAN_SERIAL_PORT
     #error "MALYAN_LCD requires MALYAN_SERIAL_PORT to be defined in Configuration.h"
   #elif MALYAN_SERIAL_PORT == SERIAL_PORT
@@ -132,6 +131,7 @@
     #error "MALYAN_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
   #elif WITHIN(MALYAN_SERIAL_PORT, 1, NUM_UARTS)
     #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_SERIAL_PORT)
+  #elif NUM_UARTS == 5
     #error "MALYAN_SERIAL_PORT must be from 1 to 5. Please update your configuration."
   #else
     #error "MALYAN_SERIAL_PORT must be from 1 to 3. Please update your configuration."
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
index c57fff81b656..8328c4930fa0 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
@@ -76,8 +76,7 @@ static inline __always_inline void my_usart_irq(ring_buffer *rb, ring_buffer *wb
 
 // Not every MarlinSerial port should handle emergency parsing.
 // It would not make sense to parse GCode from TMC responses, for example.
-constexpr bool serial_handles_emergency(int port)
-{
+constexpr bool serial_handles_emergency(int port) {
   return false
     #ifdef SERIAL_PORT
       || (SERIAL_PORT) == port
@@ -85,10 +84,10 @@ constexpr bool serial_handles_emergency(int port)
     #ifdef SERIAL_PORT_2
       || (SERIAL_PORT_2) == port
     #endif
-    #ifdef DGUS_SERIAL_PORT 
+    #ifdef DGUS_SERIAL_PORT
       || (DGUS_SERIAL_PORT) == port
     #endif
-    ;
+  ;
 }
 
 #define DEFINE_HWSERIAL_MARLIN(name, n)  \
@@ -101,13 +100,13 @@ constexpr bool serial_handles_emergency(int port)
   }
 
 #define DEFINE_HWSERIAL_UART_MARLIN(name, n) \
-MarlinSerial name(UART##n,                 \
-          BOARD_USART##n##_TX_PIN,         \
-          BOARD_USART##n##_RX_PIN,         \
-          serial_handles_emergency(n));    \
-extern "C" void __irq_usart##n(void) {     \
-  my_usart_irq(UART##n->rb, UART##n->wb, UART##n##_BASE, MSerial##n); \
-}
+  MarlinSerial name(UART##n,                 \
+          BOARD_USART##n##_TX_PIN,           \
+          BOARD_USART##n##_RX_PIN,           \
+          serial_handles_emergency(n));      \
+  extern "C" void __irq_usart##n(void) {     \
+    my_usart_irq(UART##n->rb, UART##n->wb, UART##n##_BASE, MSerial##n); \
+  }
 
 // Instantiate all UARTs even if they are not needed
 // This avoids a bunch of logic to figure out every serial
@@ -115,7 +114,7 @@ extern "C" void __irq_usart##n(void) {     \
 DEFINE_HWSERIAL_MARLIN(MSerial1, 1);
 DEFINE_HWSERIAL_MARLIN(MSerial2, 2);
 DEFINE_HWSERIAL_MARLIN(MSerial3, 3);
-#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+#if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
   DEFINE_HWSERIAL_UART_MARLIN(MSerial4, 4);
   DEFINE_HWSERIAL_UART_MARLIN(MSerial5, 5);
 #endif
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index c99f5078cf79..3aae519ec93c 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -68,7 +68,7 @@ class MarlinSerial : public HardwareSerial {
 extern MarlinSerial MSerial1;
 extern MarlinSerial MSerial2;
 extern MarlinSerial MSerial3;
-#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+#if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
   extern MarlinSerial MSerial4;
   extern MarlinSerial MSerial5;
 #endif
diff --git a/Marlin/src/HAL/STM32F1/sdio.cpp b/Marlin/src/HAL/STM32F1/sdio.cpp
index 0e9a3b2d0450..ffa6db1206ae 100644
--- a/Marlin/src/HAL/STM32F1/sdio.cpp
+++ b/Marlin/src/HAL/STM32F1/sdio.cpp
@@ -26,7 +26,7 @@
 
 #include "../../inc/MarlinConfig.h" // Allow pins/pins.h to set density
 
-#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+#if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
 
 #include "sdio.h"
 
diff --git a/Marlin/src/core/macros.h b/Marlin/src/core/macros.h
index 5fc1081019b5..4a99c32e3602 100644
--- a/Marlin/src/core/macros.h
+++ b/Marlin/src/core/macros.h
@@ -201,6 +201,12 @@
 #define BOTH(V1,V2)         ALL(V1,V2)
 #define EITHER(V1,V2)       ANY(V1,V2)
 
+// Macros to test for '0' settings
+#define SET_ZERO(D)         (defined(D) && D == 0)
+#define _ISZER_1            SET_ZERO
+#define ALL_ZERO(V...)      DO(ISZER,&&,V)
+#define ANY_ZERO(V...)      DO(ISZER,||,V)
+
 // Macros to support pins/buttons exist testing
 #define PIN_EXISTS(PN)      (defined(PN##_PIN) && PN##_PIN >= 0)
 #define _PINEX_1            PIN_EXISTS
diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index 8d68b33ece20..c6149050814c 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -395,7 +395,7 @@
   #error "PARKING_EXTRUDER_SECURITY_RAISE is now TOOLCHANGE_ZRAISE. Please update your configuration."
 #elif defined(SWITCHING_TOOLHEAD_SECURITY_RAISE)
   #error "SWITCHING_TOOLHEAD_SECURITY_RAISE is now TOOLCHANGE_ZRAISE. Please update your configuration."
-#elif defined(G0_FEEDRATE) && G0_FEEDRATE == 0
+#elif SET_ZERO(G0_FEEDRATE)
   #error "G0_FEEDRATE is now used to set the G0 feedrate. Please update your configuration."
 #elif defined(MBL_Z_STEP)
   #error "MBL_Z_STEP is now MESH_EDIT_Z_STEP. Please update your configuration."

From 62b40627f2508fcd718c101ac1dc170495219883 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 17:46:57 -0500
Subject: [PATCH 08/33] Tweak ANY_RX

---
 Marlin/src/HAL/LPC1768/inc/SanityCheck.h | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
index 350a46b44312..52dcf1784f72 100644
--- a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
+++ b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
@@ -132,27 +132,27 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #define IS_RX2(P) (P == P0_11)
   #define _IS_TX2_1 IS_TX2
   #define _IS_RX2_1 IS_RX2
-  #if IS_TX2(X2_ENABLE_PIN) || ANY_RX2(X2_DIR_PIN, X2_STEP_PIN) || (AXIS_HAS_SPI(X2) && IS_TX2(X2_CS_PIN))
+  #if IS_TX2(X2_ENABLE_PIN) || ANY_RX(2, X2_DIR_PIN, X2_STEP_PIN) || (AXIS_HAS_SPI(X2) && IS_TX2(X2_CS_PIN))
     #error "Serial port pins (2) conflict with X2 pins!"
-  #elif IS_TX2(Y2_ENABLE_PIN) || ANY_RX2(Y2_DIR_PIN, Y2_STEP_PIN) || (AXIS_HAS_SPI(Y2) && IS_TX2(Y2_CS_PIN))
+  #elif IS_TX2(Y2_ENABLE_PIN) || ANY_RX(2, Y2_DIR_PIN, Y2_STEP_PIN) || (AXIS_HAS_SPI(Y2) && IS_TX2(Y2_CS_PIN))
     #error "Serial port pins (2) conflict with Y2 pins!"
-  #elif IS_TX2(Z2_ENABLE_PIN) || ANY_RX2(Z2_DIR_PIN, Z2_STEP_PIN) || (AXIS_HAS_SPI(Z2) && IS_TX2(Z2_CS_PIN))
+  #elif IS_TX2(Z2_ENABLE_PIN) || ANY_RX(2, Z2_DIR_PIN, Z2_STEP_PIN) || (AXIS_HAS_SPI(Z2) && IS_TX2(Z2_CS_PIN))
     #error "Serial port pins (2) conflict with Z2 pins!"
-  #elif IS_TX2(Z3_ENABLE_PIN) || ANY_RX2(Z3_DIR_PIN, Z3_STEP_PIN) || (AXIS_HAS_SPI(Z3) && IS_TX2(Z3_CS_PIN))
+  #elif IS_TX2(Z3_ENABLE_PIN) || ANY_RX(2, Z3_DIR_PIN, Z3_STEP_PIN) || (AXIS_HAS_SPI(Z3) && IS_TX2(Z3_CS_PIN))
     #error "Serial port pins (2) conflict with Z3 pins!"
-  #elif IS_TX2(Z4_ENABLE_PIN) || ANY_RX2(Z4_DIR_PIN, Z4_STEP_PIN) || (AXIS_HAS_SPI(Z4) && IS_TX2(Z4_CS_PIN))
+  #elif IS_TX2(Z4_ENABLE_PIN) || ANY_RX(2, Z4_DIR_PIN, Z4_STEP_PIN) || (AXIS_HAS_SPI(Z4) && IS_TX2(Z4_CS_PIN))
     #error "Serial port pins (2) conflict with Z4 pins!"
-  #elif ANY_RX2(X_DIR_PIN, Y_DIR_PIN)
+  #elif ANY_RX(2, X_DIR_PIN, Y_DIR_PIN)
     #error "Serial port pins (2) conflict with other pins!"
   #elif Y_HOME_DIR < 0 && IS_TX2(Y_STOP_PIN)
     #error "Serial port pins (2) conflict with Y endstop pin!"
   #elif HAS_CUSTOM_PROBE_PIN && IS_TX2(Z_MIN_PROBE_PIN)
     #error "Serial port pins (2) conflict with probe pin!"
-  #elif ANY_TX2(X_ENABLE_PIN, Y_ENABLE_PIN) || ANY_RX2(X_DIR_PIN, Y_DIR_PIN)
+  #elif ANY_TX2(X_ENABLE_PIN, Y_ENABLE_PIN) || ANY_RX(2, X_DIR_PIN, Y_DIR_PIN)
     #error "Serial port pins (2) conflict with X/Y stepper pins!"
   #elif HAS_MULTI_EXTRUDER && (IS_TX2(E1_ENABLE_PIN) || (AXIS_HAS_SPI(E1) && IS_TX2(E1_CS_PIN)))
     #error "Serial port pins (2) conflict with E1 stepper pins!"
-  #elif EXTRUDERS && ANY_RX2(E0_DIR_PIN, E0_STEP_PIN)
+  #elif EXTRUDERS && ANY_RX(2, E0_DIR_PIN, E0_STEP_PIN)
     #error "Serial port pins (2) conflict with E stepper pins!"
   #endif
   #undef IS_TX2
@@ -185,6 +185,9 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #undef PIN_IS_RX3
 #endif
 
+#undef ANY_TX
+#undef ANY_RX
+
 //
 // Flag any i2c pin conflicts
 //

From 997cad7668db4399de9254b9ae3aeaba96ceb784 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 17:50:39 -0500
Subject: [PATCH 09/33] Update MarlinSerial.h

---
 Marlin/src/HAL/STM32F1/MarlinSerial.h | 12 ++++--------
 1 file changed, 4 insertions(+), 8 deletions(-)

diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index 3aae519ec93c..5c226882f702 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -35,17 +35,13 @@
 
 class MarlinSerial : public HardwareSerial {
 public:
-  MarlinSerial(struct usart_dev *usart_device, uint8 tx_pin, uint8 rx_pin, bool emergency_parser) :
+  MarlinSerial(struct usart_dev *usart_device, uint8 tx_pin, uint8 rx_pin, bool TERN_(EMERGENCY_PARSER, emergency_parser)) :
     HardwareSerial(usart_device, tx_pin, rx_pin)
     #if ENABLED(EMERGENCY_PARSER)
-      , emergency_parser_enabled(emergency_parser),
-      emergency_state(EmergencyParser::State::EP_RESET)
+      , emergency_parser_enabled(emergency_parser)
+      , emergency_state(EmergencyParser::State::EP_RESET)
     #endif
-    {
-      #if DISABLED(EMERGENCY_PARSER)
-        UNUSED(emergency_parser);
-      #endif
-    }
+    { }
 
   #ifdef UART_IRQ_PRIO
     // shadow the parent methods to set irq priority after the begin

From 4b0aa06ece96a30ab0217d05acc353389c754077 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 18:36:44 -0500
Subject: [PATCH 10/33] Fix, consolidate serial sanity-checking

---
 Marlin/Configuration.h              |  2 +-
 Marlin/src/HAL/AVR/HAL.h            | 11 --------
 Marlin/src/HAL/AVR/MarlinSerial.cpp | 20 +++++++--------
 Marlin/src/HAL/AVR/MarlinSerial.h   |  6 ++---
 Marlin/src/HAL/DUE/HAL.h            | 10 ++------
 Marlin/src/HAL/LPC1768/HAL.h        | 10 ++------
 Marlin/src/HAL/SAMD51/HAL.h         | 10 ++------
 Marlin/src/HAL/STM32/HAL.h          | 30 +++++-----------------
 Marlin/src/HAL/STM32F1/HAL.h        | 30 +++++++---------------
 Marlin/src/HAL/STM32_F4_F7/HAL.h    |  6 -----
 Marlin/src/HAL/TEENSY40_41/HAL.h    |  4 +--
 Marlin/src/gcode/config/M575.cpp    | 19 +++-----------
 Marlin/src/inc/SanityCheck.h        | 40 ++++++++++++++++++++++++-----
 Marlin/src/lcd/extui/malyan_lcd.cpp |  8 +-----
 buildroot/tests/malyan_M300-tests   |  2 +-
 15 files changed, 76 insertions(+), 132 deletions(-)

diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index ce767c7b0a85..14d4fa5355bf 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -2167,7 +2167,7 @@
 //#define MALYAN_LCD
 #if ENABLED(MALYAN_LCD)
   // This will be 1 on a Malyan M200, but may differ on other boards.
-  #define MALYAN_SERIAL_PORT 1
+  #define MALYAN_LCD_SERIAL_PORT 1
 #endif
 
 //
diff --git a/Marlin/src/HAL/AVR/HAL.h b/Marlin/src/HAL/AVR/HAL.h
index 9db3c22617b6..04d77c847c10 100644
--- a/Marlin/src/HAL/AVR/HAL.h
+++ b/Marlin/src/HAL/AVR/HAL.h
@@ -93,8 +93,6 @@ typedef int8_t pin_t;
   #ifdef SERIAL_PORT_2
     #if !WITHIN(SERIAL_PORT_2, -1, 3)
       #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
-    #elif SERIAL_PORT_2 == SERIAL_PORT
-      #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
     #endif
     #define MYSERIAL1 customizedSerial2
     #define NUM_SERIAL 2
@@ -106,23 +104,14 @@ typedef int8_t pin_t;
 #ifdef DGUS_SERIAL_PORT
   #if !WITHIN(DGUS_SERIAL_PORT, -1, 3)
     #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #endif
   #define DGUS_SERIAL internalDgusSerial
-
   #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.get_tx_buffer_free
 #endif
 
 #ifdef ANYCUBIC_LCD_SERIAL_PORT
   #if !WITHIN(ANYCUBIC_LCD_SERIAL_PORT, -1, 3)
     #error "ANYCUBIC_LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
-  #elif ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT
-    #error "ANYCUBIC_LCD_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT_2
-    #error "ANYCUBIC_LCD_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #endif
   #define ANYCUBIC_LCD_SERIAL anycubicLcdSerial
 #endif
diff --git a/Marlin/src/HAL/AVR/MarlinSerial.cpp b/Marlin/src/HAL/AVR/MarlinSerial.cpp
index 3d44a3f59ffc..838627001d14 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.cpp
+++ b/Marlin/src/HAL/AVR/MarlinSerial.cpp
@@ -712,11 +712,11 @@
   }
 
   // Hookup ISR handlers
-  ISR(SERIAL_REGNAME(USART,SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _RX_vect)) {
     MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
@@ -729,11 +729,11 @@
   #ifdef SERIAL_PORT_2
 
     // Hookup ISR handlers
-    ISR(SERIAL_REGNAME(USART,SERIAL_PORT_2,_RX_vect)) {
+    ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _RX_vect)) {
       MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::store_rxd_char();
     }
 
-    ISR(SERIAL_REGNAME(USART,SERIAL_PORT_2,_UDRE_vect)) {
+    ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _UDRE_vect)) {
       MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::_tx_udr_empty_irq();
     }
 
@@ -749,11 +749,11 @@
 
 #ifdef INTERNAL_SERIAL_PORT
 
-  ISR(SERIAL_REGNAME(USART,INTERNAL_SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, INTERNAL_SERIAL_PORT, _RX_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,INTERNAL_SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, INTERNAL_SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
@@ -776,11 +776,11 @@
     return ret;
   }
 
-  ISR(SERIAL_REGNAME(USART,DGUS_SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, DGUS_SERIAL_PORT, _RX_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,DGUS_SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, DGUS_SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
@@ -794,11 +794,11 @@
 
 #ifdef ANYCUBIC_LCD_SERIAL_PORT
 
-  ISR(SERIAL_REGNAME(USART,ANYCUBIC_LCD_SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, ANYCUBIC_LCD_SERIAL_PORT, _RX_vect)) {
     MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,ANYCUBIC_LCD_SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, ANYCUBIC_LCD_SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
diff --git a/Marlin/src/HAL/AVR/MarlinSerial.h b/Marlin/src/HAL/AVR/MarlinSerial.h
index e8bfc5583a91..8dbed4d85be4 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.h
+++ b/Marlin/src/HAL/AVR/MarlinSerial.h
@@ -48,11 +48,11 @@
 
   // These are macros to build serial port register names for the selected SERIAL_PORT (C preprocessor
   // requires two levels of indirection to expand macro values properly)
-  #define SERIAL_REGNAME(registerbase,number,suffix) SERIAL_REGNAME_INTERNAL(registerbase,number,suffix)
+  #define SERIAL_REGNAME(registerbase,number,suffix) _SERIAL_REGNAME(registerbase,number,suffix)
   #if SERIAL_PORT == 0 && (!defined(UBRR0H) || !defined(UDR0)) // use un-numbered registers if necessary
-    #define SERIAL_REGNAME_INTERNAL(registerbase,number,suffix) registerbase##suffix
+    #define _SERIAL_REGNAME(registerbase,number,suffix) registerbase##suffix
   #else
-    #define SERIAL_REGNAME_INTERNAL(registerbase,number,suffix) registerbase##number##suffix
+    #define _SERIAL_REGNAME(registerbase,number,suffix) registerbase##number##suffix
   #endif
 
   // Registers used by MarlinSerial class (expanded depending on selected serial port)
diff --git a/Marlin/src/HAL/DUE/HAL.h b/Marlin/src/HAL/DUE/HAL.h
index 9b20b7363ac4..8eb8d2aa122c 100644
--- a/Marlin/src/HAL/DUE/HAL.h
+++ b/Marlin/src/HAL/DUE/HAL.h
@@ -52,9 +52,7 @@
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different from SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1 || ENABLED(EMERGENCY_PARSER)
+  #if SERIAL_PORT_2 == -1 || ENABLED(EMERGENCY_PARSER)
     #define MYSERIAL1 customizedSerial2
   #elif WITHIN(SERIAL_PORT_2, 0, 3)
     #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
@@ -67,11 +65,7 @@
 #endif
 
 #ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different from SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
+  #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL internalDgusSerial
   #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
     #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index 7ddad121ae4a..5dd0cd040937 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -76,9 +76,7 @@ extern "C" volatile uint32_t _millis;
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1
+  #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 UsbSerial
   #elif WITHIN(SERIAL_PORT_2, 0, 3)
     #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
@@ -91,11 +89,7 @@ extern "C" volatile uint32_t _millis;
 #endif
 
 #ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
+  #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL UsbSerial
   #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
     #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index 7b1b693eadcb..dc7eb16d681a 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -47,9 +47,7 @@
   #endif
 
   #ifdef SERIAL_PORT_2
-    #if SERIAL_PORT_2 == SERIAL_PORT
-      #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
-    #elif SERIAL_PORT_2 == -1
+    #if SERIAL_PORT_2 == -1
       #define MYSERIAL1 Serial
     #elif WITHIN(SERIAL_PORT_2, 0, 3)
       #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
@@ -62,11 +60,7 @@
   #endif
 
   #ifdef DGUS_SERIAL_PORT
-    #if DGUS_SERIAL_PORT == SERIAL_PORT
-      #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-    #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-      #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-    #elif DGUS_SERIAL_PORT == -1
+    #if DGUS_SERIAL_PORT == -1
       #define DGUS_SERIAL Serial
     #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
       #define MYSERIAL0 MSERIAL(DGUS_SERIAL_PORT)
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index 46a538118ace..9435f37556a4 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -56,9 +56,7 @@
 
 #ifdef SERIAL_PORT_2
   #define NUM_SERIAL 2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1
+  #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
   #elif WITHIN(SERIAL_PORT_2, 1, 6)
     #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
@@ -71,37 +69,23 @@
 
 
 #if HAS_DGUS_LCD
-  #if DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
+  #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL SerialUSB
   #elif WITHIN(DGUS_SERIAL_PORT, 1, 6)
     #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
     #error "DGUS_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
   #endif
-
   #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.availableForWrite
 #endif
 
 #if ENABLED(MALYAN_LCD)
-  #define _FRAMEWORK_SERIAL(X) Serial##X
-  #define FRAMEWORK_SERIAL(X) _FRAMEWORK_SERIAL(X)
-
-  #ifndef MALYAN_SERIAL_PORT
-    #error "MALYAN_LCD requires MALYAN_SERIAL_PORT to be defined in Configuration.h"
-  #elif MALYAN_SERIAL_PORT == SERIAL_PORT
-    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && MALYAN_SERIAL_PORT == SERIAL_PORT_2
-    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif defined(DGUS_SERIAL) && MALYAN_SERIAL_PORT == DGUS_SERIAL_PORT
-    #error "MALYAN_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
-  #elif WITHIN(MALYAN_SERIAL_PORT, 1, 6)
-    #define MALYAN_LCD_SERIAL FRAMEWORK_SERIAL(MALYAN_SERIAL_PORT)
+  #if MALYAN_LCD_SERIAL_PORT == -1
+    #define MALYAN_LCD_SERIAL SerialUSB
+  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, 6)
+    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_LCD_SERIAL_PORT)
   #else
-    #error "MALYAN_SERIAL_PORT must be from 1 to 6. Please update your configuration."
+    #error "MALYAN_LCD_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index 6c9d98c4e7d5..415184e1c26b 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -88,9 +88,7 @@
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1
+  #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 UsbSerial
   #elif WITHIN(SERIAL_PORT_2, 1, NUM_UARTS)
     #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
@@ -105,11 +103,7 @@
 #endif
 
 #ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
+  #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL UsbSerial
   #elif WITHIN(DGUS_SERIAL_PORT, 1, NUM_UARTS)
     #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
@@ -120,21 +114,15 @@
   #endif
 #endif
 
-#if ENABLED(MALYAN_LCD)
-  #ifndef MALYAN_SERIAL_PORT
-    #error "MALYAN_LCD requires MALYAN_SERIAL_PORT to be defined in Configuration.h"
-  #elif MALYAN_SERIAL_PORT == SERIAL_PORT
-    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && MALYAN_SERIAL_PORT == SERIAL_PORT_2
-    #error "MALYAN_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif defined(DGUS_SERIAL) && MALYAN_SERIAL_PORT == DGUS_SERIAL_PORT
-    #error "MALYAN_SERIAL_PORT must be different than DGUS_SERIAL_PORT. Please update your configuration."
-  #elif WITHIN(MALYAN_SERIAL_PORT, 1, NUM_UARTS)
-    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_SERIAL_PORT)
+#if ENABLED(MALYAN_LCD_SERIAL_PORT)
+  #if MALYAN_LCD_SERIAL_PORT == -1
+    #define MALYAN_LCD_SERIAL UsbSerial
+  #if WITHIN(MALYAN_LCD_SERIAL_PORT, 1, NUM_UARTS)
+    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_LCD_SERIAL_PORT)
   #elif NUM_UARTS == 5
-    #error "MALYAN_SERIAL_PORT must be from 1 to 5. Please update your configuration."
+    #error "MALYAN_LCD_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
   #else
-    #error "MALYAN_SERIAL_PORT must be from 1 to 3. Please update your configuration."
+    #error "MALYAN_LCD_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/STM32_F4_F7/HAL.h b/Marlin/src/HAL/STM32_F4_F7/HAL.h
index 0f686c1c853e..dc46d49ca027 100644
--- a/Marlin/src/HAL/STM32_F4_F7/HAL.h
+++ b/Marlin/src/HAL/STM32_F4_F7/HAL.h
@@ -63,8 +63,6 @@
 #ifdef SERIAL_PORT_2
   #if defined(STM32F4) && SERIAL_PORT_2 == 0
     #error "SERIAL_PORT_2 cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
   #elif WITHIN(SERIAL_PORT_2, 0, 6)
@@ -80,10 +78,6 @@
 #ifdef DGUS_SERIAL_PORT
   #if defined(STM32F4) && DGUS_SERIAL_PORT == 0
     #error "DGUS_SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #elif DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL SerialUSB
   #elif WITHIN(DGUS_SERIAL_PORT, 0, 6)
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index 2e0a7c049787..cbb32a6b5190 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -63,9 +63,7 @@
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different from SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1
+  #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 usbSerial
   #elif WITHIN(SERIAL_PORT_2, 0, 8)
     #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
diff --git a/Marlin/src/gcode/config/M575.cpp b/Marlin/src/gcode/config/M575.cpp
index 3aa5844653c2..44723b7f2fe6 100644
--- a/Marlin/src/gcode/config/M575.cpp
+++ b/Marlin/src/gcode/config/M575.cpp
@@ -53,23 +53,10 @@ void GcodeSuite::M575() {
     case 115200: case 250000: case 500000: case 1000000: {
       const int8_t port = parser.intval('P', -99);
       const bool set0 = (port == -99 || port == 0);
-      if (set0) {
-        SERIAL_ECHO_START();
-        SERIAL_ECHOLNPAIR(" Serial "
-          #if HAS_MULTI_SERIAL
-            , '0',
-          #else
-            "0"
-          #endif
-          " baud rate set to ", baud
-        );
-      }
+      if (set0) SERIAL_ECHO_MSG(" Serial ", '0', " baud rate set to ", baud);
       #if HAS_MULTI_SERIAL
         const bool set1 = (port == -99 || port == 1);
-        if (set1) {
-          SERIAL_ECHO_START();
-          SERIAL_ECHOLNPAIR(" Serial ", '1', " baud rate set to ", baud);
-        }
+        if (set1) SERIAL_ECHO_MSG(" Serial ", '1', " baud rate set to ", baud);
       #endif
 
       SERIAL_FLUSH();
@@ -85,4 +72,4 @@ void GcodeSuite::M575() {
   }
 }
 
-#endif // NUM_SERIAL > 0 && BAUD_RATE_GCODE
+#endif // BAUD_RATE_GCODE
diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index c6149050814c..d32bca5a0400 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -582,12 +582,10 @@
   #error "SERIAL_XON_XOFF and SERIAL_STATS_* features not supported on USB-native AVR devices."
 #endif
 
-#if SERIAL_PORT > 7
-  #error "Set SERIAL_PORT to the port on your board. Usually this is 0."
-#endif
-
-#if defined(SERIAL_PORT_2) && NUM_SERIAL < 2
-  #error "SERIAL_PORT_2 is not supported for your MOTHERBOARD. Disable it to continue."
+#ifndef SERIAL_PORT
+  #error "SERIAL_PORT must be defined in Configuration.h"
+#elif defined(SERIAL_PORT_2) && SERIAL_PORT_2 == SERIAL_PORT
+  #error "SERIAL_PORT_2 cannot be the same as SERIAL_PORT. Please update your configuration."
 #endif
 
 /**
@@ -2280,6 +2278,36 @@ static_assert(hbm[Z_AXIS] >= 0, "HOMING_BUMP_MM.Z must be greater than or equal
   #error "Please enable only one LCD_SCREEN_ROT_* option: 0, 90, 180, or 270."
 #endif
 
+/**
+ * Serial displays require a dedicated serial port
+ */
+#if HAS_DGUS_LCD
+  #ifndef DGUS_SERIAL_PORT
+    #error "The DGUS LCD requires DGUS_SERIAL_PORT to be defined in Configuration.h"
+  #elif DGUS_SERIAL_PORT == SERIAL_PORT
+    #error "DGUS_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
+    #error "DGUS_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
+  #endif
+#elif ENABLED(MALYAN_LCD)
+  #ifndef MALYAN_LCD_SERIAL_PORT
+    #error "MALYAN_LCD requires MALYAN_LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
+    #error "MALYAN_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && MALYAN_LCD_SERIAL_PORT == SERIAL_PORT_2
+    #error "MALYAN_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
+  #endif
+#elif EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
+  #ifndef ANYCUBIC_LCD_SERIAL_PORT
+    #error "The ANYCUBIC LCD requires ANYCUBIC_LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT
+    #error "ANYCUBIC_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT_2
+    #error "ANYCUBIC_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
+  #endif
+  #define ANYCUBIC_LCD_SERIAL anycubicLcdSerial
+#endif
+
 /**
  * FYSETC Mini 12864 RGB backlighting required
  */
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index 32833f2a547f..01b9a9c3ce4f 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -45,7 +45,7 @@
 
 #if ENABLED(MALYAN_LCD)
 
-#define DEBUG_MALYAN_LCD
+//#define DEBUG_MALYAN_LCD
 
 #include "ui_api.h"
 
@@ -61,12 +61,6 @@
 #define DEBUG_OUT ENABLED(DEBUG_MALYAN_LCD)
 #include "../../core/debug_out.h"
 
-// On the Malyan M200, this will be Serial1. On a RAMPS board,
-// it might not be.
-#ifndef MALYAN_LCD_SERIAL
-  #error "Must define MALYAN_SERIAL_PORT in Configuration.h to use MALYAN_LCD"
-#endif
-
 // This is based on longest sys command + a filename, plus some buffer
 // in case we encounter some data we don't recognize
 // There is no evidence a line will ever be this long, but better safe than sorry
diff --git a/buildroot/tests/malyan_M300-tests b/buildroot/tests/malyan_M300-tests
index 06c08d3a6c98..8b41114470eb 100755
--- a/buildroot/tests/malyan_M300-tests
+++ b/buildroot/tests/malyan_M300-tests
@@ -9,7 +9,7 @@ set -e
 restore_configs
 use_example_configs "delta/Malyan M300"
 opt_disable AUTO_BED_LEVELING_3POINT
-opt_set MALYAN_SERIAL_PORT 1
+opt_set MALYAN_LCD_SERIAL_PORT 1
 exec_test $1 $2 "Malyan M300 (delta)"
 
 # cleanup

From 678799cda12a9f88d88453799eec6d33e228cd1f Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 18:42:25 -0500
Subject: [PATCH 11/33] Macro patch

---
 Marlin/src/HAL/LPC1768/HAL.h             | 2 +-
 Marlin/src/HAL/LPC1768/inc/SanityCheck.h | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index 5dd0cd040937..c7764dcaa5f1 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -63,7 +63,7 @@ extern "C" volatile uint32_t _millis;
   #define ST7920_DELAY_3 DELAY_NS(750)
 #endif
 
-#define _MSERIAL(X) Serial##X
+#define _MSERIAL(X) MSerial##X
 #define MSERIAL(X) _MSERIAL(X)
 #define MSerial0 MSerial
 
diff --git a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
index 52dcf1784f72..22d91e2bd75d 100644
--- a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
+++ b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
@@ -148,7 +148,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
     #error "Serial port pins (2) conflict with Y endstop pin!"
   #elif HAS_CUSTOM_PROBE_PIN && IS_TX2(Z_MIN_PROBE_PIN)
     #error "Serial port pins (2) conflict with probe pin!"
-  #elif ANY_TX2(X_ENABLE_PIN, Y_ENABLE_PIN) || ANY_RX(2, X_DIR_PIN, Y_DIR_PIN)
+  #elif ANY_TX(2, X_ENABLE_PIN, Y_ENABLE_PIN) || ANY_RX(2, X_DIR_PIN, Y_DIR_PIN)
     #error "Serial port pins (2) conflict with X/Y stepper pins!"
   #elif HAS_MULTI_EXTRUDER && (IS_TX2(E1_ENABLE_PIN) || (AXIS_HAS_SPI(E1) && IS_TX2(E1_CS_PIN)))
     #error "Serial port pins (2) conflict with E1 stepper pins!"

From 19abe2432e59f61f74642b8c5232e0d29e03f56e Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 18:43:52 -0500
Subject: [PATCH 12/33] prep for redo

---
 Marlin/src/HAL/STM32/HAL.h | 1 -
 1 file changed, 1 deletion(-)

diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index 9435f37556a4..dae819a7921e 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -67,7 +67,6 @@
   #define NUM_SERIAL 1
 #endif
 
-
 #if HAS_DGUS_LCD
   #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL SerialUSB

From 5cc87f9c3df6285921d7f1fe14327939c020cd87 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 18:52:16 -0500
Subject: [PATCH 13/33] Define NUM_SERIAL once

---
 Marlin/src/HAL/AVR/HAL.h         |  4 ----
 Marlin/src/HAL/DUE/HAL.h         |  3 ---
 Marlin/src/HAL/ESP32/HAL.h       |  3 ---
 Marlin/src/HAL/HAL.h             |  6 ++++++
 Marlin/src/HAL/LINUX/HAL.h       |  1 -
 Marlin/src/HAL/LPC1768/HAL.h     |  3 ---
 Marlin/src/HAL/SAMD51/HAL.h      |  3 ---
 Marlin/src/HAL/STM32/HAL.h       |  3 ---
 Marlin/src/HAL/STM32F1/HAL.h     |  3 ---
 Marlin/src/HAL/STM32_F4_F7/HAL.h |  3 ---
 Marlin/src/HAL/TEENSY31_32/HAL.h |  2 --
 Marlin/src/HAL/TEENSY35_36/HAL.h |  2 --
 Marlin/src/HAL/TEENSY40_41/HAL.h |  3 ---
 Marlin/src/MarlinCore.cpp        | 18 ++++++++----------
 14 files changed, 14 insertions(+), 43 deletions(-)

diff --git a/Marlin/src/HAL/AVR/HAL.h b/Marlin/src/HAL/AVR/HAL.h
index 04d77c847c10..fcaaf75c4a9e 100644
--- a/Marlin/src/HAL/AVR/HAL.h
+++ b/Marlin/src/HAL/AVR/HAL.h
@@ -82,7 +82,6 @@ typedef int8_t pin_t;
 // Serial ports
 #ifdef USBCON
   #define MYSERIAL0 TERN(BLUETOOTH, bluetoothSerial, Serial)
-  #define NUM_SERIAL 1
 #else
   #if !WITHIN(SERIAL_PORT, -1, 3)
     #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
@@ -95,9 +94,6 @@ typedef int8_t pin_t;
       #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
     #endif
     #define MYSERIAL1 customizedSerial2
-    #define NUM_SERIAL 2
-  #else
-    #define NUM_SERIAL 1
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/DUE/HAL.h b/Marlin/src/HAL/DUE/HAL.h
index 8eb8d2aa122c..974f1ccc1649 100644
--- a/Marlin/src/HAL/DUE/HAL.h
+++ b/Marlin/src/HAL/DUE/HAL.h
@@ -59,9 +59,6 @@
   #else
     #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL_PORT
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index c91f9efff0b9..5eb84fdc3021 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -58,9 +58,6 @@ extern portMUX_TYPE spinlock;
   #else
     #define MYSERIAL1 webSocketSerial
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #define CRITICAL_SECTION_START() portENTER_CRITICAL(&spinlock)
diff --git a/Marlin/src/HAL/HAL.h b/Marlin/src/HAL/HAL.h
index c7b7531442db..8b6a978d2103 100644
--- a/Marlin/src/HAL/HAL.h
+++ b/Marlin/src/HAL/HAL.h
@@ -25,6 +25,12 @@
 
 #include HAL_PATH(.,HAL.h)
 
+#ifdef SERIAL_PORT_2
+  #define NUM_SERIAL 2
+#else
+  #define NUM_SERIAL 1
+#endif
+
 #define HAL_ADC_RANGE _BV(HAL_ADC_RESOLUTION)
 
 #ifndef I2C_ADDRESS
diff --git a/Marlin/src/HAL/LINUX/HAL.h b/Marlin/src/HAL/LINUX/HAL.h
index 96e121d9153e..778ba2db4d71 100644
--- a/Marlin/src/HAL/LINUX/HAL.h
+++ b/Marlin/src/HAL/LINUX/HAL.h
@@ -62,7 +62,6 @@ uint8_t _getc();
 
 extern HalSerial usb_serial;
 #define MYSERIAL0 usb_serial
-#define NUM_SERIAL 1
 
 #define ST7920_DELAY_1 DELAY_NS(600)
 #define ST7920_DELAY_2 DELAY_NS(750)
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index c7764dcaa5f1..e9f05fcc617d 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -83,9 +83,6 @@ extern "C" volatile uint32_t _millis;
   #else
     #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL_PORT
diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index dc7eb16d681a..b516cb769fb3 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -54,9 +54,6 @@
     #else
       #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
     #endif
-    #define NUM_SERIAL 2
-  #else
-    #define NUM_SERIAL 1
   #endif
 
   #ifdef DGUS_SERIAL_PORT
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index dae819a7921e..38605684a1fc 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -55,7 +55,6 @@
 #endif
 
 #ifdef SERIAL_PORT_2
-  #define NUM_SERIAL 2
   #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
   #elif WITHIN(SERIAL_PORT_2, 1, 6)
@@ -63,8 +62,6 @@
   #else
     #error "SERIAL_PORT_2 must be -1 or from 1 to 6. Please update your configuration."
   #endif
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #if HAS_DGUS_LCD
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index 415184e1c26b..8d4b0dee2780 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -97,9 +97,6 @@
   #else
     #error "SERIAL_PORT_2 must be -1 or from 1 to 3. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL_PORT
diff --git a/Marlin/src/HAL/STM32_F4_F7/HAL.h b/Marlin/src/HAL/STM32_F4_F7/HAL.h
index dc46d49ca027..e132168205bb 100644
--- a/Marlin/src/HAL/STM32_F4_F7/HAL.h
+++ b/Marlin/src/HAL/STM32_F4_F7/HAL.h
@@ -70,9 +70,6 @@
   #else
     #error "SERIAL_PORT_2 must be from -1 to 6. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL_PORT
diff --git a/Marlin/src/HAL/TEENSY31_32/HAL.h b/Marlin/src/HAL/TEENSY31_32/HAL.h
index 737579b25cc3..31ceb8b87c9a 100644
--- a/Marlin/src/HAL/TEENSY31_32/HAL.h
+++ b/Marlin/src/HAL/TEENSY31_32/HAL.h
@@ -49,8 +49,6 @@
   #define IS_TEENSY32 1
 #endif
 
-#define NUM_SERIAL 1
-
 #define _MSERIAL(X) Serial##X
 #define MSERIAL(X) _MSERIAL(X)
 #define Serial0 Serial
diff --git a/Marlin/src/HAL/TEENSY35_36/HAL.h b/Marlin/src/HAL/TEENSY35_36/HAL.h
index 75541d6f2a66..11f0fb941e93 100644
--- a/Marlin/src/HAL/TEENSY35_36/HAL.h
+++ b/Marlin/src/HAL/TEENSY35_36/HAL.h
@@ -54,8 +54,6 @@
   #define IS_TEENSY36 1
 #endif
 
-#define NUM_SERIAL 1
-
 #define _MSERIAL(X) Serial##X
 #define MSERIAL(X) _MSERIAL(X)
 #define Serial0 Serial
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index cbb32a6b5190..77f7af295668 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -70,9 +70,6 @@
   #else
       #error "SERIAL_PORT_2 must be from -1 to 8. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #define HAL_SERVO_LIB libServo
diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index 22935c146073..e11439861bd4 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -912,17 +912,15 @@ void setup() {
     #endif
   #endif
 
-  #if NUM_SERIAL > 0
-    MYSERIAL0.begin(BAUDRATE);
-    uint32_t serial_connect_timeout = millis() + 1000UL;
-    while (!MYSERIAL0 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
-    #if HAS_MULTI_SERIAL
-      MYSERIAL1.begin(BAUDRATE);
-      serial_connect_timeout = millis() + 1000UL;
-      while (!MYSERIAL1 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
-    #endif
-    SERIAL_ECHO_MSG("start");
+  MYSERIAL0.begin(BAUDRATE);
+  uint32_t serial_connect_timeout = millis() + 1000UL;
+  while (!MYSERIAL0 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
+  #if HAS_MULTI_SERIAL
+    MYSERIAL1.begin(BAUDRATE);
+    serial_connect_timeout = millis() + 1000UL;
+    while (!MYSERIAL1 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
   #endif
+  SERIAL_ECHO_MSG("start");
 
   #if BOTH(HAS_TFT_LVGL_UI, USE_WIFI_FUNCTION)
     mks_esp_wifi_init();

From 2d4d58225b4c322fa594b62772636b59e20ae2cb Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 18:56:19 -0500
Subject: [PATCH 14/33] keep feet on ground

---
 Marlin/src/HAL/LPC1768/MarlinSerial.cpp  | 2 +-
 Marlin/src/HAL/LPC1768/inc/SanityCheck.h | 2 +-
 Marlin/src/core/macros.h                 | 7 ++-----
 3 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
index 6df5147e34da..c9bca3be96ac 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
@@ -24,7 +24,7 @@
 #include "../../inc/MarlinConfigPre.h"
 #include "MarlinSerial.h"
 
-#if ANY_ZERO(SERIAL_PORT, SERIAL_PORT_2, DGUS_SERIAL_PORT)
+#if IS_ZERO(SERIAL_PORT) || IS_ZERO(SERIAL_PORT_2) || IS_ZERO(DGUS_SERIAL_PORT)
   MarlinSerial MSerial(LPC_UART0);
   extern "C" void UART0_IRQHandler() {
     MSerial.IRQHandler();
diff --git a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
index 22d91e2bd75d..303d70bc434a 100644
--- a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
+++ b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
@@ -92,7 +92,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
 #define ANY_TX(N,V...) DO(IS_TX##N,||,V)
 #define ANY_RX(N,V...) DO(IS_RX##N,||,V)
 
-#if ANY_ZERO(SERIAL_PORT, SERIAL_PORT_2, DGUS_SERIAL_PORT)
+#if IS_ZERO(SERIAL_PORT) || IS_ZERO(SERIAL_PORT_2) || IS_ZERO(DGUS_SERIAL_PORT)
   #define IS_TX0(P) (P == P0_02)
   #define IS_RX0(P) (P == P0_03)
   #if IS_TX0(TMC_SW_MISO) || IS_RX0(TMC_SW_MOSI)
diff --git a/Marlin/src/core/macros.h b/Marlin/src/core/macros.h
index 4a99c32e3602..89e05fb4cb99 100644
--- a/Marlin/src/core/macros.h
+++ b/Marlin/src/core/macros.h
@@ -201,11 +201,8 @@
 #define BOTH(V1,V2)         ALL(V1,V2)
 #define EITHER(V1,V2)       ANY(V1,V2)
 
-// Macros to test for '0' settings
-#define SET_ZERO(D)         (defined(D) && D == 0)
-#define _ISZER_1            SET_ZERO
-#define ALL_ZERO(V...)      DO(ISZER,&&,V)
-#define ANY_ZERO(V...)      DO(ISZER,||,V)
+// Test for a '0' setting
+#define IS_ZERO(D)          (defined(D) && D == 0)
 
 // Macros to support pins/buttons exist testing
 #define PIN_EXISTS(PN)      (defined(PN##_PIN) && PN##_PIN >= 0)

From f16388b61515552560a5fea824aa819e751bfead Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 19:00:24 -0500
Subject: [PATCH 15/33] etc

---
 Marlin/src/HAL/LPC1768/MarlinSerial.cpp  | 2 +-
 Marlin/src/HAL/LPC1768/inc/SanityCheck.h | 2 +-
 Marlin/src/core/macros.h                 | 3 ---
 Marlin/src/inc/SanityCheck.h             | 2 +-
 4 files changed, 3 insertions(+), 6 deletions(-)

diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
index c9bca3be96ac..c3fb3bd0e4d2 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
@@ -24,7 +24,7 @@
 #include "../../inc/MarlinConfigPre.h"
 #include "MarlinSerial.h"
 
-#if IS_ZERO(SERIAL_PORT) || IS_ZERO(SERIAL_PORT_2) || IS_ZERO(DGUS_SERIAL_PORT)
+#if (defined(SERIAL_PORT) && SERIAL_PORT == 0) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == 0) || (defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT == 0)
   MarlinSerial MSerial(LPC_UART0);
   extern "C" void UART0_IRQHandler() {
     MSerial.IRQHandler();
diff --git a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
index 303d70bc434a..2ca8a29da4c6 100644
--- a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
+++ b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
@@ -92,7 +92,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
 #define ANY_TX(N,V...) DO(IS_TX##N,||,V)
 #define ANY_RX(N,V...) DO(IS_RX##N,||,V)
 
-#if IS_ZERO(SERIAL_PORT) || IS_ZERO(SERIAL_PORT_2) || IS_ZERO(DGUS_SERIAL_PORT)
+#if (defined(SERIAL_PORT) && SERIAL_PORT == 0) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == 0) || (defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT == 0)
   #define IS_TX0(P) (P == P0_02)
   #define IS_RX0(P) (P == P0_03)
   #if IS_TX0(TMC_SW_MISO) || IS_RX0(TMC_SW_MOSI)
diff --git a/Marlin/src/core/macros.h b/Marlin/src/core/macros.h
index 89e05fb4cb99..5fc1081019b5 100644
--- a/Marlin/src/core/macros.h
+++ b/Marlin/src/core/macros.h
@@ -201,9 +201,6 @@
 #define BOTH(V1,V2)         ALL(V1,V2)
 #define EITHER(V1,V2)       ANY(V1,V2)
 
-// Test for a '0' setting
-#define IS_ZERO(D)          (defined(D) && D == 0)
-
 // Macros to support pins/buttons exist testing
 #define PIN_EXISTS(PN)      (defined(PN##_PIN) && PN##_PIN >= 0)
 #define _PINEX_1            PIN_EXISTS
diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index d32bca5a0400..c34fb3c951e8 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -395,7 +395,7 @@
   #error "PARKING_EXTRUDER_SECURITY_RAISE is now TOOLCHANGE_ZRAISE. Please update your configuration."
 #elif defined(SWITCHING_TOOLHEAD_SECURITY_RAISE)
   #error "SWITCHING_TOOLHEAD_SECURITY_RAISE is now TOOLCHANGE_ZRAISE. Please update your configuration."
-#elif SET_ZERO(G0_FEEDRATE)
+#elif defined(G0_FEEDRATE) && G0_FEEDRATE == 0
   #error "G0_FEEDRATE is now used to set the G0 feedrate. Please update your configuration."
 #elif defined(MBL_Z_STEP)
   #error "MBL_Z_STEP is now MESH_EDIT_Z_STEP. Please update your configuration."

From 804d1b1015ed048372fd5ecfea470bfb8e4b2817 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 19:21:42 -0500
Subject: [PATCH 16/33] Update Configuration.h

---
 Marlin/Configuration.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index 14d4fa5355bf..c1a9f248e500 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -2166,8 +2166,7 @@
 //
 //#define MALYAN_LCD
 #if ENABLED(MALYAN_LCD)
-  // This will be 1 on a Malyan M200, but may differ on other boards.
-  #define MALYAN_LCD_SERIAL_PORT 1
+  #define MALYAN_LCD_SERIAL_PORT 1  // Default is 1 for Malyan M200
 #endif
 
 //

From d6035bcb4e8246e4c717780e56b84d645cc708f5 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 19:20:24 -0500
Subject: [PATCH 17/33] HAL and serial cleanup

---
 Marlin/src/HAL/AVR/HAL.h                      | 21 +----
 Marlin/src/HAL/AVR/MarlinSerial.cpp           | 20 ++---
 Marlin/src/HAL/AVR/MarlinSerial.h             |  6 +-
 Marlin/src/HAL/DUE/HAL.h                      | 47 +++--------
 Marlin/src/HAL/ESP32/HAL.h                    |  3 -
 Marlin/src/HAL/HAL.h                          |  6 ++
 Marlin/src/HAL/LINUX/HAL.h                    |  1 -
 Marlin/src/HAL/LPC1768/HAL.h                  | 47 +++--------
 Marlin/src/HAL/LPC1768/inc/SanityCheck.h      | 37 ++++++---
 Marlin/src/HAL/SAMD51/HAL.h                   | 46 +++--------
 Marlin/src/HAL/STM32/HAL.h                    | 81 ++++++-------------
 Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h |  2 +-
 Marlin/src/HAL/STM32F1/HAL.h                  |  5 +-
 Marlin/src/HAL/STM32F1/MarlinSerial.h         |  1 +
 Marlin/src/HAL/STM32F1/sdio.cpp               |  2 +-
 Marlin/src/HAL/STM32_F4_F7/HAL.h              | 61 +++-----------
 Marlin/src/HAL/TEENSY31_32/HAL.h              | 14 ++--
 Marlin/src/HAL/TEENSY35_36/HAL.h              | 14 ++--
 Marlin/src/HAL/TEENSY40_41/HAL.h              | 51 +++---------
 Marlin/src/MarlinCore.cpp                     | 18 ++---
 Marlin/src/gcode/config/M575.cpp              | 19 +----
 Marlin/src/inc/SanityCheck.h                  | 40 +++++++--
 Marlin/src/lcd/extui/malyan_lcd.cpp           |  2 +-
 Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h |  8 +-
 .../pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h  |  8 +-
 .../pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h  |  8 +-
 Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h  |  8 +-
 Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h      | 16 ++--
 .../pins/stm32f1/pins_MKS_ROBIN_E3_common.h   |  8 +-
 .../src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h | 16 ++--
 Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h  | 17 ++--
 31 files changed, 218 insertions(+), 415 deletions(-)

diff --git a/Marlin/src/HAL/AVR/HAL.h b/Marlin/src/HAL/AVR/HAL.h
index 609375e386e8..fcaaf75c4a9e 100644
--- a/Marlin/src/HAL/AVR/HAL.h
+++ b/Marlin/src/HAL/AVR/HAL.h
@@ -81,12 +81,7 @@ typedef int8_t pin_t;
 
 // Serial ports
 #ifdef USBCON
-  #if ENABLED(BLUETOOTH)
-    #define MYSERIAL0 bluetoothSerial
-  #else
-    #define MYSERIAL0 Serial
-  #endif
-  #define NUM_SERIAL 1
+  #define MYSERIAL0 TERN(BLUETOOTH, bluetoothSerial, Serial)
 #else
   #if !WITHIN(SERIAL_PORT, -1, 3)
     #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
@@ -97,36 +92,22 @@ typedef int8_t pin_t;
   #ifdef SERIAL_PORT_2
     #if !WITHIN(SERIAL_PORT_2, -1, 3)
       #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
-    #elif SERIAL_PORT_2 == SERIAL_PORT
-      #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
     #endif
     #define MYSERIAL1 customizedSerial2
-    #define NUM_SERIAL 2
-  #else
-    #define NUM_SERIAL 1
   #endif
 #endif
 
 #ifdef DGUS_SERIAL_PORT
   #if !WITHIN(DGUS_SERIAL_PORT, -1, 3)
     #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #endif
   #define DGUS_SERIAL internalDgusSerial
-
   #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.get_tx_buffer_free
 #endif
 
 #ifdef ANYCUBIC_LCD_SERIAL_PORT
   #if !WITHIN(ANYCUBIC_LCD_SERIAL_PORT, -1, 3)
     #error "ANYCUBIC_LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
-  #elif ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT
-    #error "ANYCUBIC_LCD_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT_2
-    #error "ANYCUBIC_LCD_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #endif
   #define ANYCUBIC_LCD_SERIAL anycubicLcdSerial
 #endif
diff --git a/Marlin/src/HAL/AVR/MarlinSerial.cpp b/Marlin/src/HAL/AVR/MarlinSerial.cpp
index 3d44a3f59ffc..838627001d14 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.cpp
+++ b/Marlin/src/HAL/AVR/MarlinSerial.cpp
@@ -712,11 +712,11 @@
   }
 
   // Hookup ISR handlers
-  ISR(SERIAL_REGNAME(USART,SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _RX_vect)) {
     MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
@@ -729,11 +729,11 @@
   #ifdef SERIAL_PORT_2
 
     // Hookup ISR handlers
-    ISR(SERIAL_REGNAME(USART,SERIAL_PORT_2,_RX_vect)) {
+    ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _RX_vect)) {
       MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::store_rxd_char();
     }
 
-    ISR(SERIAL_REGNAME(USART,SERIAL_PORT_2,_UDRE_vect)) {
+    ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _UDRE_vect)) {
       MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::_tx_udr_empty_irq();
     }
 
@@ -749,11 +749,11 @@
 
 #ifdef INTERNAL_SERIAL_PORT
 
-  ISR(SERIAL_REGNAME(USART,INTERNAL_SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, INTERNAL_SERIAL_PORT, _RX_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,INTERNAL_SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, INTERNAL_SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
@@ -776,11 +776,11 @@
     return ret;
   }
 
-  ISR(SERIAL_REGNAME(USART,DGUS_SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, DGUS_SERIAL_PORT, _RX_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,DGUS_SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, DGUS_SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
@@ -794,11 +794,11 @@
 
 #ifdef ANYCUBIC_LCD_SERIAL_PORT
 
-  ISR(SERIAL_REGNAME(USART,ANYCUBIC_LCD_SERIAL_PORT,_RX_vect)) {
+  ISR(SERIAL_REGNAME(USART, ANYCUBIC_LCD_SERIAL_PORT, _RX_vect)) {
     MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART,ANYCUBIC_LCD_SERIAL_PORT,_UDRE_vect)) {
+  ISR(SERIAL_REGNAME(USART, ANYCUBIC_LCD_SERIAL_PORT, _UDRE_vect)) {
     MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
diff --git a/Marlin/src/HAL/AVR/MarlinSerial.h b/Marlin/src/HAL/AVR/MarlinSerial.h
index e8bfc5583a91..8dbed4d85be4 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.h
+++ b/Marlin/src/HAL/AVR/MarlinSerial.h
@@ -48,11 +48,11 @@
 
   // These are macros to build serial port register names for the selected SERIAL_PORT (C preprocessor
   // requires two levels of indirection to expand macro values properly)
-  #define SERIAL_REGNAME(registerbase,number,suffix) SERIAL_REGNAME_INTERNAL(registerbase,number,suffix)
+  #define SERIAL_REGNAME(registerbase,number,suffix) _SERIAL_REGNAME(registerbase,number,suffix)
   #if SERIAL_PORT == 0 && (!defined(UBRR0H) || !defined(UDR0)) // use un-numbered registers if necessary
-    #define SERIAL_REGNAME_INTERNAL(registerbase,number,suffix) registerbase##suffix
+    #define _SERIAL_REGNAME(registerbase,number,suffix) registerbase##suffix
   #else
-    #define SERIAL_REGNAME_INTERNAL(registerbase,number,suffix) registerbase##number##suffix
+    #define _SERIAL_REGNAME(registerbase,number,suffix) registerbase##number##suffix
   #endif
 
   // Registers used by MarlinSerial class (expanded depending on selected serial port)
diff --git a/Marlin/src/HAL/DUE/HAL.h b/Marlin/src/HAL/DUE/HAL.h
index 31409c76dd56..974f1ccc1649 100644
--- a/Marlin/src/HAL/DUE/HAL.h
+++ b/Marlin/src/HAL/DUE/HAL.h
@@ -38,57 +38,34 @@
 
 #include <stdint.h>
 
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
+
 // Define MYSERIAL0/1 before MarlinSerial includes!
 #if SERIAL_PORT == -1 || ENABLED(EMERGENCY_PARSER)
   #define MYSERIAL0 customizedSerial1
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "The required SERIAL_PORT must be from -1 to 3. Please update your configuration."
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different from SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1 || ENABLED(EMERGENCY_PARSER)
+  #if SERIAL_PORT_2 == -1 || ENABLED(EMERGENCY_PARSER)
     #define MYSERIAL1 customizedSerial2
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 Serial
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 Serial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 Serial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 Serial3
+  #elif WITHIN(SERIAL_PORT_2, 0, 3)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different from SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
+  #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL internalDgusSerial
-  #elif DGUS_SERIAL_PORT == 0
-    #define DGUS_SERIAL Serial
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL Serial1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL Serial2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL Serial3
+  #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
     #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
diff --git a/Marlin/src/HAL/ESP32/HAL.h b/Marlin/src/HAL/ESP32/HAL.h
index c91f9efff0b9..5eb84fdc3021 100644
--- a/Marlin/src/HAL/ESP32/HAL.h
+++ b/Marlin/src/HAL/ESP32/HAL.h
@@ -58,9 +58,6 @@ extern portMUX_TYPE spinlock;
   #else
     #define MYSERIAL1 webSocketSerial
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #define CRITICAL_SECTION_START() portENTER_CRITICAL(&spinlock)
diff --git a/Marlin/src/HAL/HAL.h b/Marlin/src/HAL/HAL.h
index c7b7531442db..8b6a978d2103 100644
--- a/Marlin/src/HAL/HAL.h
+++ b/Marlin/src/HAL/HAL.h
@@ -25,6 +25,12 @@
 
 #include HAL_PATH(.,HAL.h)
 
+#ifdef SERIAL_PORT_2
+  #define NUM_SERIAL 2
+#else
+  #define NUM_SERIAL 1
+#endif
+
 #define HAL_ADC_RANGE _BV(HAL_ADC_RESOLUTION)
 
 #ifndef I2C_ADDRESS
diff --git a/Marlin/src/HAL/LINUX/HAL.h b/Marlin/src/HAL/LINUX/HAL.h
index 96e121d9153e..778ba2db4d71 100644
--- a/Marlin/src/HAL/LINUX/HAL.h
+++ b/Marlin/src/HAL/LINUX/HAL.h
@@ -62,7 +62,6 @@ uint8_t _getc();
 
 extern HalSerial usb_serial;
 #define MYSERIAL0 usb_serial
-#define NUM_SERIAL 1
 
 #define ST7920_DELAY_1 DELAY_NS(600)
 #define ST7920_DELAY_2 DELAY_NS(750)
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index 0153bacf42dd..e9f05fcc617d 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -63,56 +63,33 @@ extern "C" volatile uint32_t _millis;
   #define ST7920_DELAY_3 DELAY_NS(750)
 #endif
 
+#define _MSERIAL(X) MSerial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define MSerial0 MSerial
+
 #if SERIAL_PORT == -1
   #define MYSERIAL0 UsbSerial
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 MSerial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 MSerial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 MSerial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 MSerial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1
+  #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 UsbSerial
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 MSerial
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 MSerial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 MSerial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 MSerial3
+  #elif WITHIN(SERIAL_PORT_2, 0, 3)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
+  #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL UsbSerial
-  #elif DGUS_SERIAL_PORT == 0
-    #define DGUS_SERIAL MSerial
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL MSerial1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL MSerial2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL MSerial3
+  #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
     #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
diff --git a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
index 3fc1dd801a45..2ca8a29da4c6 100644
--- a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
+++ b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
@@ -89,6 +89,9 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
  * Serial2 | P0_10 | P0_11 |
  * Serial3 | P0_00 | P0_01 |
  */
+#define ANY_TX(N,V...) DO(IS_TX##N,||,V)
+#define ANY_RX(N,V...) DO(IS_RX##N,||,V)
+
 #if (defined(SERIAL_PORT) && SERIAL_PORT == 0) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == 0) || (defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT == 0)
   #define IS_TX0(P) (P == P0_02)
   #define IS_RX0(P) (P == P0_03)
@@ -106,48 +109,56 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
 #if SERIAL_PORT == 1 || SERIAL_PORT_2 == 1 || DGUS_SERIAL_PORT == 1
   #define IS_TX1(P) (P == P0_15)
   #define IS_RX1(P) (P == P0_16)
+  #define _IS_TX1_1 IS_TX1
+  #define _IS_RX1_1 IS_RX1
   #if IS_TX1(TMC_SW_SCK)
     #error "Serial port pins (1) conflict with other pins!"
   #elif HAS_SPI_LCD
     #if IS_TX1(BTN_EN2) || IS_RX1(BTN_EN1)
       #error "Serial port pins (1) conflict with Encoder Buttons!"
-    #elif IS_TX1(SCK_PIN) || IS_TX1(LCD_PINS_D4) || IS_TX1(DOGLCD_SCK) || IS_TX1(LCD_RESET_PIN) || IS_TX1(LCD_PINS_RS) || IS_TX1(SHIFT_CLK) \
-      || IS_RX1(LCD_SDSS) || IS_RX1(LCD_PINS_RS) || IS_RX1(MISO_PIN) || IS_RX1(DOGLCD_A0) || IS_RX1(SS_PIN) || IS_RX1(LCD_SDSS) || IS_RX1(DOGLCD_CS) || IS_RX1(LCD_RESET_PIN) || IS_RX1(LCD_BACKLIGHT_PIN)
+    #elif ANY_TX(1, SCK_PIN, LCD_PINS_D4, DOGLCD_SCK, LCD_RESET_PIN, LCD_PINS_RS, SHIFT_CLK) \
+       || ANY_RX(1, LCD_SDSS, LCD_PINS_RS, MISO_PIN, DOGLCD_A0, SS_PIN, LCD_SDSS, DOGLCD_CS, LCD_RESET_PIN, LCD_BACKLIGHT_PIN)
       #error "Serial port pins (1) conflict with LCD pins!"
     #endif
   #endif
   #undef IS_TX1
   #undef IS_RX1
+  #undef _IS_TX1_1
+  #undef _IS_RX1_1
 #endif
 
 #if SERIAL_PORT == 2 || SERIAL_PORT_2 == 2 || DGUS_SERIAL_PORT == 2
   #define IS_TX2(P) (P == P0_10)
   #define IS_RX2(P) (P == P0_11)
-  #if  IS_TX2(X2_ENABLE_PIN) || IS_RX2(X2_DIR_PIN) || IS_RX2(X2_STEP_PIN) || (AXIS_HAS_SPI(X2) && IS_TX2(X2_CS_PIN))
+  #define _IS_TX2_1 IS_TX2
+  #define _IS_RX2_1 IS_RX2
+  #if IS_TX2(X2_ENABLE_PIN) || ANY_RX(2, X2_DIR_PIN, X2_STEP_PIN) || (AXIS_HAS_SPI(X2) && IS_TX2(X2_CS_PIN))
     #error "Serial port pins (2) conflict with X2 pins!"
-  #elif IS_TX2(Y2_ENABLE_PIN) || IS_RX2(Y2_DIR_PIN) || IS_RX2(Y2_STEP_PIN) || (AXIS_HAS_SPI(Y2) && IS_TX2(Y2_CS_PIN))
+  #elif IS_TX2(Y2_ENABLE_PIN) || ANY_RX(2, Y2_DIR_PIN, Y2_STEP_PIN) || (AXIS_HAS_SPI(Y2) && IS_TX2(Y2_CS_PIN))
     #error "Serial port pins (2) conflict with Y2 pins!"
-  #elif IS_TX2(Z2_ENABLE_PIN) || IS_RX2(Z2_DIR_PIN) || IS_RX2(Z2_STEP_PIN) || (AXIS_HAS_SPI(Z2) && IS_TX2(Z2_CS_PIN))
+  #elif IS_TX2(Z2_ENABLE_PIN) || ANY_RX(2, Z2_DIR_PIN, Z2_STEP_PIN) || (AXIS_HAS_SPI(Z2) && IS_TX2(Z2_CS_PIN))
     #error "Serial port pins (2) conflict with Z2 pins!"
-  #elif IS_TX2(Z3_ENABLE_PIN) || IS_RX2(Z3_DIR_PIN) || IS_RX2(Z3_STEP_PIN) || (AXIS_HAS_SPI(Z3) && IS_TX2(Z3_CS_PIN))
+  #elif IS_TX2(Z3_ENABLE_PIN) || ANY_RX(2, Z3_DIR_PIN, Z3_STEP_PIN) || (AXIS_HAS_SPI(Z3) && IS_TX2(Z3_CS_PIN))
     #error "Serial port pins (2) conflict with Z3 pins!"
-  #elif IS_TX2(Z4_ENABLE_PIN) || IS_RX2(Z4_DIR_PIN) || IS_RX2(Z4_STEP_PIN) || (AXIS_HAS_SPI(Z4) && IS_TX2(Z4_CS_PIN))
+  #elif IS_TX2(Z4_ENABLE_PIN) || ANY_RX(2, Z4_DIR_PIN, Z4_STEP_PIN) || (AXIS_HAS_SPI(Z4) && IS_TX2(Z4_CS_PIN))
     #error "Serial port pins (2) conflict with Z4 pins!"
-  #elif IS_RX2(X_DIR_PIN) || IS_RX2(Y_DIR_PIN)
+  #elif ANY_RX(2, X_DIR_PIN, Y_DIR_PIN)
     #error "Serial port pins (2) conflict with other pins!"
   #elif Y_HOME_DIR < 0 && IS_TX2(Y_STOP_PIN)
     #error "Serial port pins (2) conflict with Y endstop pin!"
   #elif HAS_CUSTOM_PROBE_PIN && IS_TX2(Z_MIN_PROBE_PIN)
     #error "Serial port pins (2) conflict with probe pin!"
-  #elif IS_TX2(X_ENABLE_PIN) || IS_RX2(X_DIR_PIN) || IS_TX2(Y_ENABLE_PIN) || IS_RX2(Y_DIR_PIN)
+  #elif ANY_TX(2, X_ENABLE_PIN, Y_ENABLE_PIN) || ANY_RX(2, X_DIR_PIN, Y_DIR_PIN)
     #error "Serial port pins (2) conflict with X/Y stepper pins!"
   #elif HAS_MULTI_EXTRUDER && (IS_TX2(E1_ENABLE_PIN) || (AXIS_HAS_SPI(E1) && IS_TX2(E1_CS_PIN)))
     #error "Serial port pins (2) conflict with E1 stepper pins!"
-  #elif EXTRUDERS && (IS_RX2(E0_DIR_PIN) || IS_RX2(E0_STEP_PIN))
+  #elif EXTRUDERS && ANY_RX(2, E0_DIR_PIN, E0_STEP_PIN)
     #error "Serial port pins (2) conflict with E stepper pins!"
   #endif
   #undef IS_TX2
   #undef IS_RX2
+  #undef _IS_TX2_1
+  #undef _IS_RX2_1
 #endif
 
 #if SERIAL_PORT == 3 || SERIAL_PORT_2 == 3 || DGUS_SERIAL_PORT == 3
@@ -155,8 +166,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #define PIN_IS_RX3(P) (P##_PIN == P0_01)
   #if PIN_IS_TX3(X_MIN) || PIN_IS_RX3(X_MAX)
     #error "Serial port pins (3) conflict with X endstop pins!"
-  #elif PIN_IS_TX3(Y_SERIAL_TX) || PIN_IS_TX3(Y_SERIAL_RX) \
-    ||  PIN_IS_RX3(X_SERIAL_TX) || PIN_IS_RX3(X_SERIAL_RX)
+  #elif PIN_IS_TX3(Y_SERIAL_TX) || PIN_IS_TX3(Y_SERIAL_RX) || PIN_IS_RX3(X_SERIAL_TX) || PIN_IS_RX3(X_SERIAL_RX)
     #error "Serial port pins (3) conflict with X/Y axis UART pins!"
   #elif PIN_IS_TX3(X2_DIR) || PIN_IS_RX3(X2_STEP)
     #error "Serial port pins (3) conflict with X2 pins!"
@@ -175,6 +185,9 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #undef PIN_IS_RX3
 #endif
 
+#undef ANY_TX
+#undef ANY_RX
+
 //
 // Flag any i2c pin conflicts
 //
diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index ea0f694cdc02..b516cb769fb3 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -35,56 +35,32 @@
 
   // MYSERIAL0 required before MarlinSerial includes!
 
+  #define _MSERIAL(X) Serial##X
+  #define MSERIAL(X) _MSERIAL(INCREMENT(X))
+
   #if SERIAL_PORT == -1
     #define MYSERIAL0 Serial
-  #elif SERIAL_PORT == 0
-    #define MYSERIAL0 Serial1
-  #elif SERIAL_PORT == 1
-    #define MYSERIAL0 Serial2
-  #elif SERIAL_PORT == 2
-    #define MYSERIAL0 Serial3
-  #elif SERIAL_PORT == 3
-    #define MYSERIAL0 Serial4
+  #elif WITHIN(SERIAL_PORT, 0, 3)
+    #define MYSERIAL0 MSERIAL(SERIAL_PORT)
   #else
     #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
 
   #ifdef SERIAL_PORT_2
-    #if SERIAL_PORT_2 == SERIAL_PORT
-      #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
-    #elif SERIAL_PORT_2 == -1
+    #if SERIAL_PORT_2 == -1
       #define MYSERIAL1 Serial
-    #elif SERIAL_PORT_2 == 0
-      #define MYSERIAL1 Serial1
-    #elif SERIAL_PORT_2 == 1
-      #define MYSERIAL1 Serial2
-    #elif SERIAL_PORT_2 == 2
-      #define MYSERIAL1 Serial3
-    #elif SERIAL_PORT_2 == 3
-      #define MYSERIAL1 Serial4
+    #elif WITHIN(SERIAL_PORT_2, 0, 3)
+      #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
     #else
       #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
     #endif
-    #define NUM_SERIAL 2
-  #else
-    #define NUM_SERIAL 1
   #endif
 
   #ifdef DGUS_SERIAL_PORT
-    #if DGUS_SERIAL_PORT == SERIAL_PORT
-      #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-    #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-      #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-    #elif DGUS_SERIAL_PORT == -1
+    #if DGUS_SERIAL_PORT == -1
       #define DGUS_SERIAL Serial
-    #elif DGUS_SERIAL_PORT == 0
-      #define DGUS_SERIAL Serial1
-    #elif DGUS_SERIAL_PORT == 1
-      #define DGUS_SERIAL Serial2
-    #elif DGUS_SERIAL_PORT == 2
-      #define DGUS_SERIAL Serial3
-    #elif DGUS_SERIAL_PORT == 2
-      #define DGUS_SERIAL Serial4
+    #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
+      #define MYSERIAL0 MSERIAL(DGUS_SERIAL_PORT)
     #else
       #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
     #endif
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index 08081331b736..9ec2d5c19e83 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -43,82 +43,47 @@
 // ------------------------
 // Defines
 // ------------------------
+#define _MSERIAL(X) MSerial##X
+#define MSERIAL(X) _MSERIAL(X)
 
-#if SERIAL_PORT == 0
-  #error "SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-#elif SERIAL_PORT == -1
+#if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 MSerial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 MSerial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 MSerial3
-#elif SERIAL_PORT == 4
-  #define MYSERIAL0 MSerial4
-#elif SERIAL_PORT == 5
-  #define MYSERIAL0 MSerial5
-#elif SERIAL_PORT == 6
-  #define MYSERIAL0 MSerial6
+#elif WITHIN(SERIAL_PORT, 1, 6)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
-  #error "SERIAL_PORT must be from -1 to 6. Please update your configuration."
+  #error "SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
 #endif
 
 #ifdef SERIAL_PORT_2
-  #define NUM_SERIAL 2
-  #if SERIAL_PORT_2 == 0
-    #error "SERIAL_PORT_2 cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1
+  #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 MSerial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 MSerial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 MSerial3
-  #elif SERIAL_PORT_2 == 4
-    #define MYSERIAL1 MSerial4
-  #elif SERIAL_PORT_2 == 5
-    #define MYSERIAL1 MSerial5
-  #elif SERIAL_PORT_2 == 6
-    #define MYSERIAL1 MSerial6
+  #elif WITHIN(SERIAL_PORT_2, 1, 6)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
-    #error "SERIAL_PORT_2 must be from -1 to 6. Please update your configuration."
+    #error "SERIAL_PORT_2 must be -1 or from 1 to 6. Please update your configuration."
   #endif
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #if HAS_DGUS_LCD
-  #if DGUS_SERIAL_PORT == 0
-    #error "DGUS_SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
+  #if DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL SerialUSB
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL MSerial1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL MSerial2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL MSerial3
-  #elif DGUS_SERIAL_PORT == 4
-    #define DGUS_SERIAL MSerial4
-  #elif DGUS_SERIAL_PORT == 5
-    #define DGUS_SERIAL MSerial5
-  #elif DGUS_SERIAL_PORT == 6
-    #define DGUS_SERIAL MSerial6
+  #elif WITHIN(DGUS_SERIAL_PORT, 1, 6)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
-    #error "DGUS_SERIAL_PORT must be from -1 to 6. Please update your configuration."
+    #error "DGUS_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
   #endif
-
   #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.availableForWrite
 #endif
 
+#if ENABLED(MALYAN_LCD)
+  #if LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL SerialUSB
+  #elif WITHIN(LCD_SERIAL_PORT, 1, 6)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
+  #else
+    #error "LCD_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
+  #endif
+#endif
 
 /**
  * TODO: review this to return 1 for pins that are not analog input
diff --git a/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h b/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h
index 5ff40debea5e..9069d9f7bd8a 100644
--- a/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h
+++ b/Marlin/src/HAL/STM32/pinsDebug_STM32GENERIC.h
@@ -98,7 +98,7 @@ static inline void pwm_details(const pin_t pin) {
     timer_dev * const tdev = PIN_MAP[pin].timer_device;
     const uint8_t channel = PIN_MAP[pin].timer_channel;
     const char num = (
-      #if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+      #if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
         tdev == &timer8 ? '8' :
         tdev == &timer5 ? '5' :
       #endif
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index f76d8c54a0e3..47414cb45e10 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -53,7 +53,7 @@
 // ------------------------
 
 #ifndef STM32_FLASH_SIZE
-  #if defined(MCU_STM32F103RE) || defined(MCU_STM32F103VE)
+  #if EITHER(MCU_STM32F103RE, MCU_STM32F103VE)
     #define STM32_FLASH_SIZE 512
   #else
     #define STM32_FLASH_SIZE 256
@@ -106,9 +106,6 @@
   #else
     #error "SERIAL_PORT_2 must be from -1 to 5. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index eb0059bfbcae..b9248e50caff 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -30,6 +30,7 @@
   #include "../../feature/e_parser.h"
 #endif
 
+// Increase priority of serial interrupts, to reduce overflow errors
 #define UART_IRQ_PRIO 1
 
 class MarlinSerial : public HardwareSerial {
diff --git a/Marlin/src/HAL/STM32F1/sdio.cpp b/Marlin/src/HAL/STM32F1/sdio.cpp
index 0e9a3b2d0450..ffa6db1206ae 100644
--- a/Marlin/src/HAL/STM32F1/sdio.cpp
+++ b/Marlin/src/HAL/STM32F1/sdio.cpp
@@ -26,7 +26,7 @@
 
 #include "../../inc/MarlinConfig.h" // Allow pins/pins.h to set density
 
-#if defined(STM32_HIGH_DENSITY) || defined(STM32_XL_DENSITY)
+#if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
 
 #include "sdio.h"
 
diff --git a/Marlin/src/HAL/STM32_F4_F7/HAL.h b/Marlin/src/HAL/STM32_F4_F7/HAL.h
index 5601400c5ac9..e132168205bb 100644
--- a/Marlin/src/HAL/STM32_F4_F7/HAL.h
+++ b/Marlin/src/HAL/STM32_F4_F7/HAL.h
@@ -46,24 +46,16 @@
 // Serial override
 //extern HalSerial usb_serial;
 
+#define _MSERIAL(X) SerialUART##X
+#define MSERIAL(X) _MSERIAL(X)
+#define SerialUART0 Serial1
+
 #if defined(STM32F4) && SERIAL_PORT == 0
   #error "SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
 #elif SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 SerialUART1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 SerialUART2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 SerialUART3
-#elif SERIAL_PORT == 4
-  #define MYSERIAL0 SerialUART4
-#elif SERIAL_PORT == 5
-  #define MYSERIAL0 SerialUART5
-#elif SERIAL_PORT == 6
-  #define MYSERIAL0 SerialUART6
+#elif WITHIN(SERIAL_PORT, 0, 6)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "SERIAL_PORT must be from -1 to 6. Please update your configuration."
 #endif
@@ -71,55 +63,22 @@
 #ifdef SERIAL_PORT_2
   #if defined(STM32F4) && SERIAL_PORT_2 == 0
     #error "SERIAL_PORT_2 cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different than SERIAL_PORT. Please update your configuration."
   #elif SERIAL_PORT_2 == -1
     #define MYSERIAL1 SerialUSB
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 Serial1
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 SerialUART1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 SerialUART2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 SerialUART3
-  #elif SERIAL_PORT_2 == 4
-    #define MYSERIAL1 SerialUART4
-  #elif SERIAL_PORT_2 == 5
-    #define MYSERIAL1 SerialUART5
-  #elif SERIAL_PORT_2 == 6
-    #define MYSERIAL1 SerialUART6
+  #elif WITHIN(SERIAL_PORT_2, 0, 6)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
     #error "SERIAL_PORT_2 must be from -1 to 6. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #ifdef DGUS_SERIAL_PORT
   #if defined(STM32F4) && DGUS_SERIAL_PORT == 0
     #error "DGUS_SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT must be different than SERIAL_PORT_2. Please update your configuration."
   #elif DGUS_SERIAL_PORT == -1
     #define DGUS_SERIAL SerialUSB
-  #elif DGUS_SERIAL_PORT == 0
-    #define DGUS_SERIAL Serial1
-  #elif DGUS_SERIAL_PORT == 1
-    #define DGUS_SERIAL SerialUART1
-  #elif DGUS_SERIAL_PORT == 2
-    #define DGUS_SERIAL SerialUART2
-  #elif DGUS_SERIAL_PORT == 3
-    #define DGUS_SERIAL SerialUART3
-  #elif DGUS_SERIAL_PORT == 4
-    #define DGUS_SERIAL SerialUART4
-  #elif DGUS_SERIAL_PORT == 5
-    #define DGUS_SERIAL SerialUART5
-  #elif DGUS_SERIAL_PORT == 6
-    #define DGUS_SERIAL SerialUART6
+  #elif WITHIN(DGUS_SERIAL_PORT, 0, 6)
+    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
   #else
     #error "DGUS_SERIAL_PORT must be from -1 to 6. Please update your configuration."
   #endif
diff --git a/Marlin/src/HAL/TEENSY31_32/HAL.h b/Marlin/src/HAL/TEENSY31_32/HAL.h
index ad095cba83cc..31ceb8b87c9a 100644
--- a/Marlin/src/HAL/TEENSY31_32/HAL.h
+++ b/Marlin/src/HAL/TEENSY31_32/HAL.h
@@ -49,18 +49,14 @@
   #define IS_TEENSY32 1
 #endif
 
-#define NUM_SERIAL 1
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
 
 #if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #endif
 
 #define HAL_SERVO_LIB libServo
diff --git a/Marlin/src/HAL/TEENSY35_36/HAL.h b/Marlin/src/HAL/TEENSY35_36/HAL.h
index 96be08d7b7ca..11f0fb941e93 100644
--- a/Marlin/src/HAL/TEENSY35_36/HAL.h
+++ b/Marlin/src/HAL/TEENSY35_36/HAL.h
@@ -54,18 +54,14 @@
   #define IS_TEENSY36 1
 #endif
 
-#define NUM_SERIAL 1
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
 
 #if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
+#elif WITHIN(SERIAL_PORT, 0, 3)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #endif
 
 #define HAL_SERVO_LIB libServo
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index 0626d4ee9cda..77f7af295668 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -50,59 +50,26 @@
   #define IS_TEENSY41 1
 #endif
 
+#define _MSERIAL(X) Serial##X
+#define MSERIAL(X) _MSERIAL(X)
+#define Serial0 Serial
+
 #if SERIAL_PORT == -1
   #define MYSERIAL0 SerialUSB
-#elif SERIAL_PORT == 0
-  #define MYSERIAL0 Serial
-#elif SERIAL_PORT == 1
-  #define MYSERIAL0 Serial1
-#elif SERIAL_PORT == 2
-  #define MYSERIAL0 Serial2
-#elif SERIAL_PORT == 3
-  #define MYSERIAL0 Serial3
-#elif SERIAL_PORT == 4
-  #define MYSERIAL0 Serial4
-#elif SERIAL_PORT == 5
-  #define MYSERIAL0 Serial5
-#elif SERIAL_PORT == 6
-  #define MYSERIAL0 Serial6
-#elif SERIAL_PORT == 7
-  #define MYSERIAL0 Serial7
-#elif SERIAL_PORT == 8
-  #define MYSERIAL0 Serial8
+#elif WITHIN(SERIAL_PORT, 0, 8)
+  #define MYSERIAL0 MSERIAL(SERIAL_PORT)
 #else
   #error "The required SERIAL_PORT must be from -1 to 8. Please update your configuration."
 #endif
 
 #ifdef SERIAL_PORT_2
-  #if SERIAL_PORT_2 == SERIAL_PORT
-    #error "SERIAL_PORT_2 must be different from SERIAL_PORT. Please update your configuration."
-  #elif SERIAL_PORT_2 == -1
+  #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 usbSerial
-  #elif SERIAL_PORT_2 == 0
-    #define MYSERIAL1 Serial
-  #elif SERIAL_PORT_2 == 1
-    #define MYSERIAL1 Serial1
-  #elif SERIAL_PORT_2 == 2
-    #define MYSERIAL1 Serial2
-  #elif SERIAL_PORT_2 == 3
-    #define MYSERIAL1 Serial3
-  #elif SERIAL_PORT_2 == 4
-    #define MYSERIAL1 Serial4
-  #elif SERIAL_PORT_2 == 5
-    #define MYSERIAL1 Serial5
-  #elif SERIAL_PORT_2 == 6
-    #define MYSERIAL1 Serial6
-  #elif SERIAL_PORT_2 == 7
-    #define MYSERIAL1 Serial7
-  #elif SERIAL_PORT_2 == 8
-    #define MYSERIAL1 Serial8
+  #elif WITHIN(SERIAL_PORT_2, 0, 8)
+    #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
   #else
       #error "SERIAL_PORT_2 must be from -1 to 8. Please update your configuration."
   #endif
-  #define NUM_SERIAL 2
-#else
-  #define NUM_SERIAL 1
 #endif
 
 #define HAL_SERVO_LIB libServo
diff --git a/Marlin/src/MarlinCore.cpp b/Marlin/src/MarlinCore.cpp
index 22935c146073..e11439861bd4 100644
--- a/Marlin/src/MarlinCore.cpp
+++ b/Marlin/src/MarlinCore.cpp
@@ -912,17 +912,15 @@ void setup() {
     #endif
   #endif
 
-  #if NUM_SERIAL > 0
-    MYSERIAL0.begin(BAUDRATE);
-    uint32_t serial_connect_timeout = millis() + 1000UL;
-    while (!MYSERIAL0 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
-    #if HAS_MULTI_SERIAL
-      MYSERIAL1.begin(BAUDRATE);
-      serial_connect_timeout = millis() + 1000UL;
-      while (!MYSERIAL1 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
-    #endif
-    SERIAL_ECHO_MSG("start");
+  MYSERIAL0.begin(BAUDRATE);
+  uint32_t serial_connect_timeout = millis() + 1000UL;
+  while (!MYSERIAL0 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
+  #if HAS_MULTI_SERIAL
+    MYSERIAL1.begin(BAUDRATE);
+    serial_connect_timeout = millis() + 1000UL;
+    while (!MYSERIAL1 && PENDING(millis(), serial_connect_timeout)) { /*nada*/ }
   #endif
+  SERIAL_ECHO_MSG("start");
 
   #if BOTH(HAS_TFT_LVGL_UI, USE_WIFI_FUNCTION)
     mks_esp_wifi_init();
diff --git a/Marlin/src/gcode/config/M575.cpp b/Marlin/src/gcode/config/M575.cpp
index 3aa5844653c2..44723b7f2fe6 100644
--- a/Marlin/src/gcode/config/M575.cpp
+++ b/Marlin/src/gcode/config/M575.cpp
@@ -53,23 +53,10 @@ void GcodeSuite::M575() {
     case 115200: case 250000: case 500000: case 1000000: {
       const int8_t port = parser.intval('P', -99);
       const bool set0 = (port == -99 || port == 0);
-      if (set0) {
-        SERIAL_ECHO_START();
-        SERIAL_ECHOLNPAIR(" Serial "
-          #if HAS_MULTI_SERIAL
-            , '0',
-          #else
-            "0"
-          #endif
-          " baud rate set to ", baud
-        );
-      }
+      if (set0) SERIAL_ECHO_MSG(" Serial ", '0', " baud rate set to ", baud);
       #if HAS_MULTI_SERIAL
         const bool set1 = (port == -99 || port == 1);
-        if (set1) {
-          SERIAL_ECHO_START();
-          SERIAL_ECHOLNPAIR(" Serial ", '1', " baud rate set to ", baud);
-        }
+        if (set1) SERIAL_ECHO_MSG(" Serial ", '1', " baud rate set to ", baud);
       #endif
 
       SERIAL_FLUSH();
@@ -85,4 +72,4 @@ void GcodeSuite::M575() {
   }
 }
 
-#endif // NUM_SERIAL > 0 && BAUD_RATE_GCODE
+#endif // BAUD_RATE_GCODE
diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index 8d68b33ece20..4c0b68e8aec0 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -582,12 +582,10 @@
   #error "SERIAL_XON_XOFF and SERIAL_STATS_* features not supported on USB-native AVR devices."
 #endif
 
-#if SERIAL_PORT > 7
-  #error "Set SERIAL_PORT to the port on your board. Usually this is 0."
-#endif
-
-#if defined(SERIAL_PORT_2) && NUM_SERIAL < 2
-  #error "SERIAL_PORT_2 is not supported for your MOTHERBOARD. Disable it to continue."
+#ifndef SERIAL_PORT
+  #error "SERIAL_PORT must be defined in Configuration.h"
+#elif defined(SERIAL_PORT_2) && SERIAL_PORT_2 == SERIAL_PORT
+  #error "SERIAL_PORT_2 cannot be the same as SERIAL_PORT. Please update your configuration."
 #endif
 
 /**
@@ -2280,6 +2278,36 @@ static_assert(hbm[Z_AXIS] >= 0, "HOMING_BUMP_MM.Z must be greater than or equal
   #error "Please enable only one LCD_SCREEN_ROT_* option: 0, 90, 180, or 270."
 #endif
 
+/**
+ * Serial displays require a dedicated serial port
+ */
+#if HAS_DGUS_LCD
+  #ifndef DGUS_SERIAL_PORT
+    #error "The DGUS LCD requires DGUS_SERIAL_PORT to be defined in Configuration.h"
+  #elif DGUS_SERIAL_PORT == SERIAL_PORT
+    #error "DGUS_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
+    #error "DGUS_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
+  #endif
+#elif ENABLED(MALYAN_LCD)
+  #ifndef LCD_SERIAL_PORT
+    #error "MALYAN_LCD requires LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif LCD_SERIAL_PORT == SERIAL_PORT
+    #error "LCD_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && LCD_SERIAL_PORT == SERIAL_PORT_2
+    #error "LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
+  #endif
+#elif EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
+  #ifndef ANYCUBIC_LCD_SERIAL_PORT
+    #error "The ANYCUBIC LCD requires ANYCUBIC_LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT
+    #error "ANYCUBIC_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT_2
+    #error "ANYCUBIC_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
+  #endif
+  #define ANYCUBIC_LCD_SERIAL anycubicLcdSerial
+#endif
+
 /**
  * FYSETC Mini 12864 RGB backlighting required
  */
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index b5148065c7cc..986373f66c51 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -45,7 +45,7 @@
 
 #if ENABLED(MALYAN_LCD)
 
-#define DEBUG_MALYAN_LCD
+//#define DEBUG_MALYAN_LCD
 
 #include "ui_api.h"
 
diff --git a/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h b/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
index f018a40c3ef3..a3cb987fff0b 100644
--- a/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
+++ b/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
@@ -117,10 +117,10 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial
diff --git a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h
index b658f3d714b8..78751a6bac87 100644
--- a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h
+++ b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V1_0.h
@@ -30,8 +30,8 @@
  * Hardware serial communication ports.
  */
 #if HAS_TMC_UART
-  #define X_HARDWARE_SERIAL  Serial4
-  #define Y_HARDWARE_SERIAL  Serial4
-  #define Z_HARDWARE_SERIAL  Serial4
-  #define E0_HARDWARE_SERIAL Serial4
+  #define X_HARDWARE_SERIAL  MSerial4
+  #define Y_HARDWARE_SERIAL  MSerial4
+  #define Z_HARDWARE_SERIAL  MSerial4
+  #define E0_HARDWARE_SERIAL MSerial4
 #endif
diff --git a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h
index cb94f0bdcacd..0a0d857db3f4 100644
--- a/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h
+++ b/Marlin/src/pins/stm32f1/pins_BTT_SKR_MINI_E3_V2_0.h
@@ -52,8 +52,8 @@
  * Hardware serial communication ports.
  */
 #if HAS_TMC_UART
-  #define X_HARDWARE_SERIAL  Serial4
-  #define Y_HARDWARE_SERIAL  Serial4
-  #define Z_HARDWARE_SERIAL  Serial4
-  #define E0_HARDWARE_SERIAL Serial4
+  #define X_HARDWARE_SERIAL  MSerial4
+  #define Y_HARDWARE_SERIAL  MSerial4
+  #define Z_HARDWARE_SERIAL  MSerial4
+  #define E0_HARDWARE_SERIAL MSerial4
 #endif
diff --git a/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h b/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h
index b7db592e7809..a04d6d261f8c 100644
--- a/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h
+++ b/Marlin/src/pins/stm32f1/pins_FYSETC_AIO_II.h
@@ -93,10 +93,10 @@
   //
   // Hardware serial with switch
   //
-  #define X_HARDWARE_SERIAL  Serial1
-  #define Y_HARDWARE_SERIAL  Serial1
-  #define Z_HARDWARE_SERIAL  Serial1
-  #define E0_HARDWARE_SERIAL Serial1
+  #define X_HARDWARE_SERIAL  MSerial1
+  #define Y_HARDWARE_SERIAL  MSerial1
+  #define Z_HARDWARE_SERIAL  MSerial1
+  #define E0_HARDWARE_SERIAL MSerial1
 
   // The 4xTMC2209 module doesn't have a serial multiplexer and
   // needs to set *_SLAVE_ADDRESS in Configuration_adv.h for X,Y,Z,E0
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h
index e39c8f234285..48da17adc5a9 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN.h
@@ -188,17 +188,11 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define X2_HARDWARE_SERIAL Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Y2_HARDWARE_SERIAL Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define Z2_HARDWARE_SERIAL Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
-  //#define E1_HARDWARE_SERIAL Serial1
-  //#define E2_HARDWARE_SERIAL Serial1
-  //#define E3_HARDWARE_SERIAL Serial1
-  //#define E4_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
+  //#define E1_HARDWARE_SERIAL MSerial1
 
   // Unused servo pins may be repurposed with SoftwareSerialM
   //#define X_SERIAL_TX_PIN                 PF8   // SERVO3_PIN -- XS2 - 6
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h
index f6a3b555c399..bbacbf5585d3 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_E3_common.h
@@ -83,10 +83,10 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h
index ccb07b35f88c..be3b130c858f 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_NANO_V2.h
@@ -132,17 +132,11 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define X2_HARDWARE_SERIAL Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Y2_HARDWARE_SERIAL Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define Z2_HARDWARE_SERIAL Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
-  //#define E1_HARDWARE_SERIAL Serial1
-  //#define E2_HARDWARE_SERIAL Serial1
-  //#define E3_HARDWARE_SERIAL Serial1
-  //#define E4_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
+  //#define E1_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial
diff --git a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h
index 2e74b6b15f2b..e445b8169bb5 100644
--- a/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h
+++ b/Marlin/src/pins/stm32f1/pins_MKS_ROBIN_PRO.h
@@ -125,17 +125,12 @@
    * Hardware serial communication ports.
    * If undefined software serial is used according to the pins below
    */
-  //#define X_HARDWARE_SERIAL  Serial1
-  //#define X2_HARDWARE_SERIAL Serial1
-  //#define Y_HARDWARE_SERIAL  Serial1
-  //#define Y2_HARDWARE_SERIAL Serial1
-  //#define Z_HARDWARE_SERIAL  Serial1
-  //#define Z2_HARDWARE_SERIAL Serial1
-  //#define E0_HARDWARE_SERIAL Serial1
-  //#define E1_HARDWARE_SERIAL Serial1
-  //#define E2_HARDWARE_SERIAL Serial1
-  //#define E3_HARDWARE_SERIAL Serial1
-  //#define E4_HARDWARE_SERIAL Serial1
+  //#define X_HARDWARE_SERIAL  MSerial1
+  //#define Y_HARDWARE_SERIAL  MSerial1
+  //#define Z_HARDWARE_SERIAL  MSerial1
+  //#define E0_HARDWARE_SERIAL MSerial1
+  //#define E1_HARDWARE_SERIAL MSerial1
+  //#define E2_HARDWARE_SERIAL MSerial1
 
   //
   // Software serial

From 3732dd89c0466648dee44dbaebf7c577b75490f3 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 19:27:52 -0500
Subject: [PATCH 18/33] typo

---
 Marlin/src/HAL/STM32F1/HAL.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index 8d4b0dee2780..e5974ae3ddbe 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -114,7 +114,7 @@
 #if ENABLED(MALYAN_LCD_SERIAL_PORT)
   #if MALYAN_LCD_SERIAL_PORT == -1
     #define MALYAN_LCD_SERIAL UsbSerial
-  #if WITHIN(MALYAN_LCD_SERIAL_PORT, 1, NUM_UARTS)
+  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, NUM_UARTS)
     #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_LCD_SERIAL_PORT)
   #elif NUM_UARTS == 5
     #error "MALYAN_LCD_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."

From d974f7ac477d9759c76631cd9276ccc2145d8517 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 19:32:44 -0500
Subject: [PATCH 19/33] fix test

---
 Marlin/src/HAL/STM32F1/HAL.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index e5974ae3ddbe..428aa1d9aa27 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -111,7 +111,7 @@
   #endif
 #endif
 
-#if ENABLED(MALYAN_LCD_SERIAL_PORT)
+#ifdef MALYAN_LCD_SERIAL_PORT
   #if MALYAN_LCD_SERIAL_PORT == -1
     #define MALYAN_LCD_SERIAL UsbSerial
   #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, NUM_UARTS)

From e24ee2e6d5e8baa6cf004e9bf4997beba16e61cd Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 21:03:41 -0500
Subject: [PATCH 20/33] Consolidate LCD_SERIAL defines

---
 Marlin/Configuration.h                        |  4 +-
 Marlin/Configuration_adv.h                    | 10 +--
 Marlin/src/HAL/AVR/HAL.h                      | 17 ++---
 Marlin/src/HAL/AVR/MarlinSerial.cpp           | 66 +++++++------------
 Marlin/src/HAL/AVR/MarlinSerial.h             | 65 +++++++++---------
 Marlin/src/HAL/DUE/HAL.h                      | 12 ++--
 Marlin/src/HAL/LPC1768/HAL.h                  | 12 ++--
 Marlin/src/HAL/LPC1768/MarlinSerial.cpp       |  8 +--
 Marlin/src/HAL/LPC1768/inc/SanityCheck.h      |  8 +--
 Marlin/src/HAL/SAMD51/HAL.h                   | 12 ++--
 Marlin/src/HAL/STM32/HAL.h                    | 24 +++----
 Marlin/src/HAL/STM32/MarlinSerial.cpp         |  4 +-
 Marlin/src/HAL/STM32F1/HAL.h                  | 28 ++++----
 Marlin/src/HAL/STM32F1/MarlinSerial.cpp       | 12 ++--
 Marlin/src/HAL/STM32_F4_F7/HAL.h              | 16 ++---
 Marlin/src/inc/Conditionals_adv.h             | 34 ++++++++++
 Marlin/src/inc/SanityCheck.h                  | 43 +++++-------
 Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp  | 22 +++----
 .../anycubic_i3mega/anycubic_i3mega_lcd.cpp   | 20 +++---
 Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp | 44 ++++++-------
 Marlin/src/lcd/extui/malyan_lcd.cpp           | 10 +--
 buildroot/tests/malyan_M300-tests             |  2 +-
 22 files changed, 232 insertions(+), 241 deletions(-)

diff --git a/Marlin/Configuration.h b/Marlin/Configuration.h
index c1a9f248e500..93e2a0229a71 100644
--- a/Marlin/Configuration.h
+++ b/Marlin/Configuration.h
@@ -2166,7 +2166,7 @@
 //
 //#define MALYAN_LCD
 #if ENABLED(MALYAN_LCD)
-  #define MALYAN_LCD_SERIAL_PORT 1  // Default is 1 for Malyan M200
+  #define LCD_SERIAL_PORT 1  // Default is 1 for Malyan M200
 #endif
 
 //
@@ -2181,7 +2181,7 @@
 //#define ANYCUBIC_LCD_I3MEGA
 //#define ANYCUBIC_LCD_CHIRON
 #if EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
-  #define ANYCUBIC_LCD_SERIAL_PORT 3
+  #define LCD_SERIAL_PORT 3  // Default is 3 for Anycubic
   //#define ANYCUBIC_LCD_DEBUG
 #endif
 
diff --git a/Marlin/Configuration_adv.h b/Marlin/Configuration_adv.h
index 65cbd21a947b..a8c9205538ad 100644
--- a/Marlin/Configuration_adv.h
+++ b/Marlin/Configuration_adv.h
@@ -1404,8 +1404,8 @@
 // Additional options for DGUS / DWIN displays
 //
 #if HAS_DGUS_LCD
-  #define DGUS_SERIAL_PORT 3
-  #define DGUS_BAUDRATE 115200
+  #define LCD_SERIAL_PORT 3
+  #define LCD_BAUDRATE 115200
 
   #define DGUS_RX_BUFFER_SIZE 128
   #define DGUS_TX_BUFFER_SIZE 48
@@ -3419,10 +3419,10 @@
 #if ENABLED(PRUSA_MMU2)
 
   // Serial port used for communication with MMU2.
-  // For AVR enable the UART port used for the MMU. (e.g., internalSerial)
+  // For AVR enable the UART port used for the MMU. (e.g., mmuSerial)
   // For 32-bit boards check your HAL for available serial ports. (e.g., Serial2)
-  #define INTERNAL_SERIAL_PORT 2
-  #define MMU2_SERIAL internalSerial
+  #define MMU2_SERIAL_PORT 2
+  #define MMU2_SERIAL mmuSerial
 
   // Use hardware reset for MMU if a pin is defined for it
   //#define MMU2_RST_PIN 23
diff --git a/Marlin/src/HAL/AVR/HAL.h b/Marlin/src/HAL/AVR/HAL.h
index fcaaf75c4a9e..790ad872ac0b 100644
--- a/Marlin/src/HAL/AVR/HAL.h
+++ b/Marlin/src/HAL/AVR/HAL.h
@@ -97,19 +97,14 @@ typedef int8_t pin_t;
   #endif
 #endif
 
-#ifdef DGUS_SERIAL_PORT
-  #if !WITHIN(DGUS_SERIAL_PORT, -1, 3)
-    #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+#ifdef LCD_SERIAL_PORT
+  #if !WITHIN(LCD_SERIAL_PORT, -1, 3)
+    #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
-  #define DGUS_SERIAL internalDgusSerial
-  #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.get_tx_buffer_free
-#endif
-
-#ifdef ANYCUBIC_LCD_SERIAL_PORT
-  #if !WITHIN(ANYCUBIC_LCD_SERIAL_PORT, -1, 3)
-    #error "ANYCUBIC_LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+  #define LCD_SERIAL lcdSerial
+  #if HAS_DGUS_LCD
+    #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.get_tx_buffer_free()
   #endif
-  #define ANYCUBIC_LCD_SERIAL anycubicLcdSerial
 #endif
 
 // ------------------------
diff --git a/Marlin/src/HAL/AVR/MarlinSerial.cpp b/Marlin/src/HAL/AVR/MarlinSerial.cpp
index 838627001d14..4d654c0d8082 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.cpp
+++ b/Marlin/src/HAL/AVR/MarlinSerial.cpp
@@ -747,66 +747,50 @@
 
 #endif // !USBCON && (UBRRH || UBRR0H || UBRR1H || UBRR2H || UBRR3H)
 
-#ifdef INTERNAL_SERIAL_PORT
+#ifdef MMU2_SERIAL_PORT
 
-  ISR(SERIAL_REGNAME(USART, INTERNAL_SERIAL_PORT, _RX_vect)) {
-    MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>>::store_rxd_char();
+  ISR(SERIAL_REGNAME(USART, MMU2_SERIAL_PORT, _RX_vect)) {
+    MarlinSerial<MMU2SerialCfg<MMU2_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART, INTERNAL_SERIAL_PORT, _UDRE_vect)) {
-    MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>>::_tx_udr_empty_irq();
+  ISR(SERIAL_REGNAME(USART, MMU2_SERIAL_PORT, _UDRE_vect)) {
+    MarlinSerial<MMU2SerialCfg<MMU2_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
   // Preinstantiate
-  template class MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>>;
+  template class MarlinSerial<MMU2SerialCfg<MMU2_SERIAL_PORT>>;
 
   // Instantiate
-  MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>> internalSerial;
+  MarlinSerial<MMU2SerialCfg<MMU2_SERIAL_PORT>> mmuSerial;
 
 #endif
 
-#ifdef DGUS_SERIAL_PORT
+#ifdef LCD_SERIAL_PORT
 
-  template<typename Cfg>
-  typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::get_tx_buffer_free() {
-    const ring_buffer_pos_t t = tx_buffer.tail,  // next byte to send.
-                            h = tx_buffer.head;  // next pos for queue.
-    int ret = t - h - 1;
-    if (ret < 0) ret += Cfg::TX_SIZE + 1;
-    return ret;
-  }
-
-  ISR(SERIAL_REGNAME(USART, DGUS_SERIAL_PORT, _RX_vect)) {
-    MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>>::store_rxd_char();
-  }
-
-  ISR(SERIAL_REGNAME(USART, DGUS_SERIAL_PORT, _UDRE_vect)) {
-    MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>>::_tx_udr_empty_irq();
-  }
-
-  // Preinstantiate
-  template class MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>>;
-
-  // Instantiate
-  MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>> internalDgusSerial;
-
-#endif
-
-#ifdef ANYCUBIC_LCD_SERIAL_PORT
-
-  ISR(SERIAL_REGNAME(USART, ANYCUBIC_LCD_SERIAL_PORT, _RX_vect)) {
-    MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>>::store_rxd_char();
+  ISR(SERIAL_REGNAME(USART, LCD_SERIAL_PORT, _RX_vect)) {
+    MarlinSerial<LCDSerialCfg<LCD_SERIAL_PORT>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART, ANYCUBIC_LCD_SERIAL_PORT, _UDRE_vect)) {
-    MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>>::_tx_udr_empty_irq();
+  ISR(SERIAL_REGNAME(USART, LCD_SERIAL_PORT, _UDRE_vect)) {
+    MarlinSerial<LCDSerialCfg<LCD_SERIAL_PORT>>::_tx_udr_empty_irq();
   }
 
   // Preinstantiate
-  template class MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>>;
+  template class MarlinSerial<LCDSerialCfg<LCD_SERIAL_PORT>>;
 
   // Instantiate
-  MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>> anycubicLcdSerial;
+  MarlinSerial<LCDSerialCfg<LCD_SERIAL_PORT>> lcdSerial;
+
+  #if HAS_DGUS_LCD
+    template<typename Cfg>
+    typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::get_tx_buffer_free() {
+      const ring_buffer_pos_t t = tx_buffer.tail,  // next byte to send.
+                              h = tx_buffer.head;  // next pos for queue.
+      int ret = t - h - 1;
+      if (ret < 0) ret += Cfg::TX_SIZE + 1;
+      return ret;
+    }
+  #endif
 
 #endif
 
diff --git a/Marlin/src/HAL/AVR/MarlinSerial.h b/Marlin/src/HAL/AVR/MarlinSerial.h
index 8dbed4d85be4..3d581cac4bb9 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.h
+++ b/Marlin/src/HAL/AVR/MarlinSerial.h
@@ -217,7 +217,7 @@
       static ring_buffer_pos_t available();
       static void write(const uint8_t c);
       static void flushTX();
-      #ifdef DGUS_SERIAL_PORT
+      #ifdef LCD_SERIAL_PORT
         static ring_buffer_pos_t get_tx_buffer_free();
       #endif
 
@@ -278,55 +278,50 @@
 
 #endif // !USBCON
 
-#ifdef INTERNAL_SERIAL_PORT
+#ifdef MMU2_SERIAL_PORT
   template <uint8_t serial>
-  struct MarlinInternalSerialCfg {
+  struct MMU2SerialCfg {
     static constexpr int PORT               = serial;
-    static constexpr unsigned int RX_SIZE   = 32;
-    static constexpr unsigned int TX_SIZE   = 32;
     static constexpr bool XONOFF            = false;
     static constexpr bool EMERGENCYPARSER   = false;
     static constexpr bool DROPPED_RX        = false;
-    static constexpr bool RX_OVERRUNS       = false;
     static constexpr bool RX_FRAMING_ERRORS = false;
     static constexpr bool MAX_RX_QUEUED     = false;
+    static constexpr unsigned int RX_SIZE   = 32;
+    static constexpr unsigned int TX_SIZE   = 32;
+    static constexpr bool RX_OVERRUNS       = false;
   };
 
-  extern MarlinSerial<MarlinInternalSerialCfg<INTERNAL_SERIAL_PORT>> internalSerial;
+  extern MarlinSerial<MMU2SerialCfg<MMU2_SERIAL_PORT>> mmuSerial;
 #endif
 
-#ifdef DGUS_SERIAL_PORT
-  template <uint8_t serial>
-  struct MarlinInternalSerialCfg {
-    static constexpr int PORT               = serial;
-    static constexpr unsigned int RX_SIZE   = DGUS_RX_BUFFER_SIZE;
-    static constexpr unsigned int TX_SIZE   = DGUS_TX_BUFFER_SIZE;
-    static constexpr bool XONOFF            = false;
-    static constexpr bool EMERGENCYPARSER   = false;
-    static constexpr bool DROPPED_RX        = false;
-    static constexpr bool RX_OVERRUNS       = BOTH(HAS_DGUS_LCD, DGUS_SERIAL_STATS_RX_BUFFER_OVERRUNS);
-    static constexpr bool RX_FRAMING_ERRORS = false;
-    static constexpr bool MAX_RX_QUEUED     = false;
-  };
-
-  extern MarlinSerial<MarlinInternalSerialCfg<DGUS_SERIAL_PORT>> internalDgusSerial;
-#endif
+#ifdef LCD_SERIAL_PORT
 
-#ifdef ANYCUBIC_LCD_SERIAL_PORT
   template <uint8_t serial>
-  struct AnycubicLcdSerialCfg {
-    static constexpr int PORT               = serial;
-    static constexpr unsigned int RX_SIZE   = 64;
-    static constexpr unsigned int TX_SIZE   = 128;
-    static constexpr bool XONOFF            = false;
-    static constexpr bool EMERGENCYPARSER   = false;
-    static constexpr bool DROPPED_RX        = false;
-    static constexpr bool RX_OVERRUNS       = false;
-    static constexpr bool RX_FRAMING_ERRORS = false;
-    static constexpr bool MAX_RX_QUEUED     = false;
+  struct LCDSerialCfg {
+    static constexpr int PORT                 = serial;
+    static constexpr bool XONOFF              = false;
+    static constexpr bool EMERGENCYPARSER     = ENABLED(EMERGENCY_PARSER);
+    static constexpr bool DROPPED_RX          = false;
+    static constexpr bool RX_FRAMING_ERRORS   = false;
+    static constexpr bool MAX_RX_QUEUED       = false;
+    #if HAS_DGUS_LCD
+      static constexpr unsigned int RX_SIZE   = DGUS_RX_BUFFER_SIZE;
+      static constexpr unsigned int TX_SIZE   = DGUS_TX_BUFFER_SIZE;
+      static constexpr bool RX_OVERRUNS       = ENABLED(DGUS_SERIAL_STATS_RX_BUFFER_OVERRUNS);
+    #elif EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
+      static constexpr unsigned int RX_SIZE   = 64;
+      static constexpr unsigned int TX_SIZE   = 128;
+      static constexpr bool RX_OVERRUNS       = false;
+    #else
+      static constexpr unsigned int RX_SIZE   = 64;
+      static constexpr unsigned int TX_SIZE   = 128;
+      static constexpr bool RX_OVERRUNS       = false
+    #endif
   };
 
-  extern MarlinSerial<AnycubicLcdSerialCfg<ANYCUBIC_LCD_SERIAL_PORT>> anycubicLcdSerial;
+  extern MarlinSerial<LCDSerialCfg<LCD_SERIAL_PORT>> lcdSerial;
+
 #endif
 
 // Use the UART for Bluetooth in AT90USB configurations
diff --git a/Marlin/src/HAL/DUE/HAL.h b/Marlin/src/HAL/DUE/HAL.h
index 974f1ccc1649..7a057fdae4fc 100644
--- a/Marlin/src/HAL/DUE/HAL.h
+++ b/Marlin/src/HAL/DUE/HAL.h
@@ -61,13 +61,13 @@
   #endif
 #endif
 
-#ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == -1
-    #define DGUS_SERIAL internalDgusSerial
-  #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
-    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
+#ifdef LCD_SERIAL_PORT
+  #if LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL lcdSerial
+  #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
   #else
-    #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/LPC1768/HAL.h b/Marlin/src/HAL/LPC1768/HAL.h
index e9f05fcc617d..3118aed1b246 100644
--- a/Marlin/src/HAL/LPC1768/HAL.h
+++ b/Marlin/src/HAL/LPC1768/HAL.h
@@ -85,13 +85,13 @@ extern "C" volatile uint32_t _millis;
   #endif
 #endif
 
-#ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == -1
-    #define DGUS_SERIAL UsbSerial
-  #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
-    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
+#ifdef LCD_SERIAL_PORT
+  #if LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL UsbSerial
+  #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
   #else
-    #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
index c3fb3bd0e4d2..5374e005d3da 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.cpp
@@ -24,28 +24,28 @@
 #include "../../inc/MarlinConfigPre.h"
 #include "MarlinSerial.h"
 
-#if (defined(SERIAL_PORT) && SERIAL_PORT == 0) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == 0) || (defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT == 0)
+#if USING_SERIAL_0
   MarlinSerial MSerial(LPC_UART0);
   extern "C" void UART0_IRQHandler() {
     MSerial.IRQHandler();
   }
 #endif
 
-#if SERIAL_PORT == 1 || SERIAL_PORT_2 == 1 || DGUS_SERIAL_PORT == 1
+#if USING_SERIAL_1
   MarlinSerial MSerial1((LPC_UART_TypeDef *) LPC_UART1);
   extern "C" void UART1_IRQHandler() {
     MSerial1.IRQHandler();
   }
 #endif
 
-#if SERIAL_PORT == 2 || SERIAL_PORT_2 == 2 || DGUS_SERIAL_PORT == 2
+#if USING_SERIAL_2
   MarlinSerial MSerial2(LPC_UART2);
   extern "C" void UART2_IRQHandler() {
     MSerial2.IRQHandler();
   }
 #endif
 
-#if SERIAL_PORT == 3 || SERIAL_PORT_2 == 3 || DGUS_SERIAL_PORT == 3
+#if USING_SERIAL_3
   MarlinSerial MSerial3(LPC_UART3);
   extern "C" void UART3_IRQHandler() {
     MSerial3.IRQHandler();
diff --git a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
index 2ca8a29da4c6..b6491368cd2a 100644
--- a/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
+++ b/Marlin/src/HAL/LPC1768/inc/SanityCheck.h
@@ -92,7 +92,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
 #define ANY_TX(N,V...) DO(IS_TX##N,||,V)
 #define ANY_RX(N,V...) DO(IS_RX##N,||,V)
 
-#if (defined(SERIAL_PORT) && SERIAL_PORT == 0) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == 0) || (defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT == 0)
+#if USING_SERIAL_0
   #define IS_TX0(P) (P == P0_02)
   #define IS_RX0(P) (P == P0_03)
   #if IS_TX0(TMC_SW_MISO) || IS_RX0(TMC_SW_MOSI)
@@ -106,7 +106,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #undef IS_RX0
 #endif
 
-#if SERIAL_PORT == 1 || SERIAL_PORT_2 == 1 || DGUS_SERIAL_PORT == 1
+#if USING_SERIAL_1
   #define IS_TX1(P) (P == P0_15)
   #define IS_RX1(P) (P == P0_16)
   #define _IS_TX1_1 IS_TX1
@@ -127,7 +127,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #undef _IS_RX1_1
 #endif
 
-#if SERIAL_PORT == 2 || SERIAL_PORT_2 == 2 || DGUS_SERIAL_PORT == 2
+#if USING_SERIAL_2
   #define IS_TX2(P) (P == P0_10)
   #define IS_RX2(P) (P == P0_11)
   #define _IS_TX2_1 IS_TX2
@@ -161,7 +161,7 @@ static_assert(DISABLED(BAUD_RATE_GCODE), "BAUD_RATE_GCODE is not yet supported o
   #undef _IS_RX2_1
 #endif
 
-#if SERIAL_PORT == 3 || SERIAL_PORT_2 == 3 || DGUS_SERIAL_PORT == 3
+#if USING_SERIAL_3
   #define PIN_IS_TX3(P) (PIN_EXISTS(P) && P##_PIN == P0_00)
   #define PIN_IS_RX3(P) (P##_PIN == P0_01)
   #if PIN_IS_TX3(X_MIN) || PIN_IS_RX3(X_MAX)
diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index b516cb769fb3..7b532cd59816 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -56,13 +56,13 @@
     #endif
   #endif
 
-  #ifdef DGUS_SERIAL_PORT
-    #if DGUS_SERIAL_PORT == -1
-      #define DGUS_SERIAL Serial
-    #elif WITHIN(DGUS_SERIAL_PORT, 0, 3)
-      #define MYSERIAL0 MSERIAL(DGUS_SERIAL_PORT)
+  #ifdef LCD_SERIAL_PORT
+    #if LCD_SERIAL_PORT == -1
+      #define LCD_SERIAL Serial
+    #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
+      #define MYSERIAL0 MSERIAL(LCD_SERIAL_PORT)
     #else
-      #error "DGUS_SERIAL_PORT must be from -1 to 3. Please update your configuration."
+      #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
     #endif
   #endif
 
diff --git a/Marlin/src/HAL/STM32/HAL.h b/Marlin/src/HAL/STM32/HAL.h
index 38605684a1fc..60ab45374a56 100644
--- a/Marlin/src/HAL/STM32/HAL.h
+++ b/Marlin/src/HAL/STM32/HAL.h
@@ -64,24 +64,16 @@
   #endif
 #endif
 
-#if HAS_DGUS_LCD
-  #if DGUS_SERIAL_PORT == -1
-    #define DGUS_SERIAL SerialUSB
-  #elif WITHIN(DGUS_SERIAL_PORT, 1, 6)
-    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
+#ifdef LCD_SERIAL_PORT
+  #if LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL SerialUSB
+  #elif WITHIN(LCD_SERIAL_PORT, 1, 6)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
   #else
-    #error "DGUS_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
   #endif
-  #define DGUS_SERIAL_GET_TX_BUFFER_FREE DGUS_SERIAL.availableForWrite
-#endif
-
-#if ENABLED(MALYAN_LCD)
-  #if MALYAN_LCD_SERIAL_PORT == -1
-    #define MALYAN_LCD_SERIAL SerialUSB
-  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, 6)
-    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_LCD_SERIAL_PORT)
-  #else
-    #error "MALYAN_LCD_SERIAL_PORT must be -1 or from 1 to 6. Please update your configuration."
+  #if HAS_DGUS_LCD
+    #define SERIAL_GET_TX_BUFFER_FREE() LCD_SERIAL.availableForWrite()
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/STM32/MarlinSerial.cpp b/Marlin/src/HAL/STM32/MarlinSerial.cpp
index 2d799ea54db0..a146664366df 100644
--- a/Marlin/src/HAL/STM32/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32/MarlinSerial.cpp
@@ -49,8 +49,8 @@
   DECLARE_SERIAL_PORT_EXP(SERIAL_PORT_2)
 #endif
 
-#if defined(DGUS_SERIAL_PORT) && DGUS_SERIAL_PORT >= 0
-  DECLARE_SERIAL_PORT_EXP(DGUS_SERIAL_PORT)
+#if defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT >= 0
+  DECLARE_SERIAL_PORT_EXP(LCD_SERIAL_PORT)
 #endif
 
 void MarlinSerial::begin(unsigned long baud, uint8_t config) {
diff --git a/Marlin/src/HAL/STM32F1/HAL.h b/Marlin/src/HAL/STM32F1/HAL.h
index 428aa1d9aa27..45da0fe962d3 100644
--- a/Marlin/src/HAL/STM32F1/HAL.h
+++ b/Marlin/src/HAL/STM32F1/HAL.h
@@ -99,27 +99,27 @@
   #endif
 #endif
 
-#ifdef DGUS_SERIAL_PORT
-  #if DGUS_SERIAL_PORT == -1
-    #define DGUS_SERIAL UsbSerial
-  #elif WITHIN(DGUS_SERIAL_PORT, 1, NUM_UARTS)
-    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
+#ifdef LCD_SERIAL_PORT
+  #if LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL UsbSerial
+  #elif WITHIN(LCD_SERIAL_PORT, 1, NUM_UARTS)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
   #elif NUM_UARTS == 5
-    #error "DGUS_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
   #else
-    #error "DGUS_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
   #endif
 #endif
 
-#ifdef MALYAN_LCD_SERIAL_PORT
-  #if MALYAN_LCD_SERIAL_PORT == -1
-    #define MALYAN_LCD_SERIAL UsbSerial
-  #elif WITHIN(MALYAN_LCD_SERIAL_PORT, 1, NUM_UARTS)
-    #define MALYAN_LCD_SERIAL MSERIAL(MALYAN_LCD_SERIAL_PORT)
+#ifdef LCD_SERIAL_PORT
+  #if LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL UsbSerial
+  #elif WITHIN(LCD_SERIAL_PORT, 1, NUM_UARTS)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
   #elif NUM_UARTS == 5
-    #error "MALYAN_LCD_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be -1 or from 1 to 5. Please update your configuration."
   #else
-    #error "MALYAN_LCD_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be -1 or from 1 to 3. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
index 8328c4930fa0..9418403c7a6d 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
@@ -84,8 +84,8 @@ constexpr bool serial_handles_emergency(int port) {
     #ifdef SERIAL_PORT_2
       || (SERIAL_PORT_2) == port
     #endif
-    #ifdef DGUS_SERIAL_PORT
-      || (DGUS_SERIAL_PORT) == port
+    #ifdef LCD_SERIAL_PORT
+      || (LCD_SERIAL_PORT) == port
     #endif
   ;
 }
@@ -138,11 +138,11 @@ constexpr bool IsSerialClassAllowed(const HardwareSerial&) { return false; }
 #ifdef MYSERIAL1
   CHECK_CFG_SERIAL(MYSERIAL1);
 #endif
-#ifdef DGUS_SERIAL
-  CHECK_CFG_SERIAL(DGUS_SERIAL);
+#ifdef LCD_SERIAL
+  CHECK_CFG_SERIAL(LCD_SERIAL);
 #endif
-#ifdef MALYAN_LCD_SERIAL
-  CHECK_CFG_SERIAL(MALYAN_LCD_SERIAL);
+#ifdef LCD_SERIAL
+  CHECK_CFG_SERIAL(LCD_SERIAL);
 #endif
 #if AXIS_HAS_HW_SERIAL(X)
   CHECK_AXIS_SERIAL(X);
diff --git a/Marlin/src/HAL/STM32_F4_F7/HAL.h b/Marlin/src/HAL/STM32_F4_F7/HAL.h
index e132168205bb..88e48f0fa09d 100644
--- a/Marlin/src/HAL/STM32_F4_F7/HAL.h
+++ b/Marlin/src/HAL/STM32_F4_F7/HAL.h
@@ -72,15 +72,15 @@
   #endif
 #endif
 
-#ifdef DGUS_SERIAL_PORT
-  #if defined(STM32F4) && DGUS_SERIAL_PORT == 0
-    #error "DGUS_SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
-  #elif DGUS_SERIAL_PORT == -1
-    #define DGUS_SERIAL SerialUSB
-  #elif WITHIN(DGUS_SERIAL_PORT, 0, 6)
-    #define DGUS_SERIAL MSERIAL(DGUS_SERIAL_PORT)
+#ifdef LCD_SERIAL_PORT
+  #if defined(STM32F4) && LCD_SERIAL_PORT == 0
+    #error "LCD_SERIAL_PORT cannot be 0. (Port 0 does not exist.) Please update your configuration."
+  #elif LCD_SERIAL_PORT == -1
+    #define LCD_SERIAL SerialUSB
+  #elif WITHIN(LCD_SERIAL_PORT, 0, 6)
+    #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
   #else
-    #error "DGUS_SERIAL_PORT must be from -1 to 6. Please update your configuration."
+    #error "LCD_SERIAL_PORT must be from -1 to 6. Please update your configuration."
   #endif
 #endif
 
diff --git a/Marlin/src/inc/Conditionals_adv.h b/Marlin/src/inc/Conditionals_adv.h
index 73e034d05f2f..d3f608e0a476 100644
--- a/Marlin/src/inc/Conditionals_adv.h
+++ b/Marlin/src/inc/Conditionals_adv.h
@@ -422,3 +422,37 @@
 #if ANY(AUTO_BED_LEVELING_UBL, AUTO_BED_LEVELING_LINEAR, Z_STEPPER_ALIGN_KNOWN_STEPPER_POSITIONS)
   #define NEED_LSF 1
 #endif
+
+// Flag the indexed serial ports that are in use
+#define ANY_SERIAL_IS(N) (defined(SERIAL_PORT) && SERIAL_PORT == (N)) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == (N)) || (defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT == (N))
+#if ANY_SERIAL_IS(-1)
+  #define USING_SERIAL_DEFAULT
+#endif
+#if ANY_SERIAL_IS(0)
+  #define USING_SERIAL_0 1
+#endif
+#if ANY_SERIAL_IS(1)
+  #define USING_SERIAL_1 1
+#endif
+#if ANY_SERIAL_IS(2)
+  #define USING_SERIAL_2 1
+#endif
+#if ANY_SERIAL_IS(3)
+  #define USING_SERIAL_3 1
+#endif
+#if ANY_SERIAL_IS(4)
+  #define USING_SERIAL_4 1
+#endif
+#if ANY_SERIAL_IS(5)
+  #define USING_SERIAL_5 1
+#endif
+#if ANY_SERIAL_IS(6)
+  #define USING_SERIAL_6 1
+#endif
+#if ANY_SERIAL_IS(7)
+  #define USING_SERIAL_7 1
+#endif
+#if ANY_SERIAL_IS(8)
+  #define USING_SERIAL_8 1
+#endif
+#undef ANY_SERIAL_IS
diff --git a/Marlin/src/inc/SanityCheck.h b/Marlin/src/inc/SanityCheck.h
index c34fb3c951e8..27bafe00485e 100644
--- a/Marlin/src/inc/SanityCheck.h
+++ b/Marlin/src/inc/SanityCheck.h
@@ -477,6 +477,10 @@
   #error "HOME_USING_SPREADCYCLE is now obsolete. Please remove it from Configuration_adv.h."
 #elif defined(DGUS_LCD)
   #error "DGUS_LCD is now DGUS_LCD_UI_(ORIGIN|FYSETC|HIPRECY). Please update your configuration."
+#elif defined(DGUS_SERIAL_PORT)
+  #error "DGUS_SERIAL_PORT is now LCD_SERIAL_PORT. Please update your configuration."
+#elif defined(DGUS_BAUDRATE)
+  #error "DGUS_BAUDRATE is now LCD_BAUDRATE. Please update your configuration."
 #elif defined(X_DUAL_ENDSTOPS_ADJUSTMENT)
   #error "X_DUAL_ENDSTOPS_ADJUSTMENT is now X2_ENDSTOP_ADJUSTMENT. Please update Configuration_adv.h."
 #elif defined(Y_DUAL_ENDSTOPS_ADJUSTMENT)
@@ -2281,31 +2285,20 @@ static_assert(hbm[Z_AXIS] >= 0, "HOMING_BUMP_MM.Z must be greater than or equal
 /**
  * Serial displays require a dedicated serial port
  */
-#if HAS_DGUS_LCD
-  #ifndef DGUS_SERIAL_PORT
-    #error "The DGUS LCD requires DGUS_SERIAL_PORT to be defined in Configuration.h"
-  #elif DGUS_SERIAL_PORT == SERIAL_PORT
-    #error "DGUS_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && DGUS_SERIAL_PORT == SERIAL_PORT_2
-    #error "DGUS_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
-  #endif
-#elif ENABLED(MALYAN_LCD)
-  #ifndef MALYAN_LCD_SERIAL_PORT
-    #error "MALYAN_LCD requires MALYAN_LCD_SERIAL_PORT to be defined in Configuration.h"
-  #elif MALYAN_LCD_SERIAL_PORT == SERIAL_PORT
-    #error "MALYAN_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && MALYAN_LCD_SERIAL_PORT == SERIAL_PORT_2
-    #error "MALYAN_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
-  #endif
-#elif EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
-  #ifndef ANYCUBIC_LCD_SERIAL_PORT
-    #error "The ANYCUBIC LCD requires ANYCUBIC_LCD_SERIAL_PORT to be defined in Configuration.h"
-  #elif ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT
-    #error "ANYCUBIC_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
-  #elif defined(SERIAL_PORT_2) && ANYCUBIC_LCD_SERIAL_PORT == SERIAL_PORT_2
-    #error "ANYCUBIC_LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
-  #endif
-  #define ANYCUBIC_LCD_SERIAL anycubicLcdSerial
+#ifdef LCD_SERIAL_PORT
+  #if LCD_SERIAL_PORT == SERIAL_PORT
+    #error "LCD_SERIAL_PORT cannot be the same as SERIAL_PORT. Please update your configuration."
+  #elif defined(SERIAL_PORT_2) && LCD_SERIAL_PORT == SERIAL_PORT_2
+    #error "LCD_SERIAL_PORT cannot be the same as SERIAL_PORT_2. Please update your configuration."
+  #endif
+#else
+  #if HAS_DGUS_LCD
+    #error "The DGUS LCD requires LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif EITHER(ANYCUBIC_LCD_I3MEGA, ANYCUBIC_LCD_CHIRON)
+    #error "The ANYCUBIC LCD requires LCD_SERIAL_PORT to be defined in Configuration.h"
+  #elif ENABLED(MALYAN_LCD)
+    #error "MALYAN_LCD requires LCD_SERIAL_PORT to be defined in Configuration.h"
+  #endif
 #endif
 
 /**
diff --git a/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp b/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
index 889a25b85950..96856c9e0b47 100644
--- a/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
+++ b/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
@@ -53,12 +53,12 @@ static bool is_printing_from_sd = false;
 static bool is_out_of_filament = false;
 
 static void sendNewLine(void) {
-  ANYCUBIC_LCD_SERIAL.write('\r');
-  ANYCUBIC_LCD_SERIAL.write('\n');
+  LCD_SERIAL.write('\r');
+  LCD_SERIAL.write('\n');
 }
 
 static void send(const char *str) {
-  ANYCUBIC_LCD_SERIAL.print(str);
+  LCD_SERIAL.print(str);
 }
 
 static void sendLine(const char *str) {
@@ -68,7 +68,7 @@ static void sendLine(const char *str) {
 
 static void send_P(PGM_P str) {
   while (const char c = pgm_read_byte(str++))
-    ANYCUBIC_LCD_SERIAL.write(c);
+    LCD_SERIAL.write(c);
 }
 
 static void sendLine_P(PGM_P str) {
@@ -78,23 +78,23 @@ static void sendLine_P(PGM_P str) {
 
 static void sendValue_P(PGM_P prefix, int value) {
   send_P(prefix);
-  ANYCUBIC_LCD_SERIAL.print(value);
+  LCD_SERIAL.print(value);
 }
 
 static void sendValue_P(PGM_P prefix, float value) {
   send_P(prefix);
-  ANYCUBIC_LCD_SERIAL.print(value);
+  LCD_SERIAL.print(value);
 }
 
 static void sendValueLine_P(PGM_P prefix, int value) {
   send_P(prefix);
-  ANYCUBIC_LCD_SERIAL.print(value);
+  LCD_SERIAL.print(value);
   sendNewLine();
 }
 
 static void sendValueLine_P(PGM_P prefix, float value) {
   send_P(prefix);
-  ANYCUBIC_LCD_SERIAL.print(value);
+  LCD_SERIAL.print(value);
   sendNewLine();
 }
 
@@ -426,8 +426,8 @@ namespace ExtUI {
     static char rxBuffer[RX_LEN_MAX+1];
     static uint8_t rxLen = 0;
 
-    while (ANYCUBIC_LCD_SERIAL.available()) {
-      const char c = ANYCUBIC_LCD_SERIAL.read();
+    while (LCD_SERIAL.available()) {
+      const char c = LCD_SERIAL.read();
       switch (c) {
         case '\r': case '\n':
           if (rxLen > 0 && rxLen <= RX_LEN_MAX) {
@@ -466,7 +466,7 @@ namespace ExtUI {
   }
 
   void onStartup() {
-    ANYCUBIC_LCD_SERIAL.begin(115200);
+    LCD_SERIAL.begin(115200);
     sendNewLine();
     SENDLINE_PGM("J17"); // Reset
     delay_ms(10);
diff --git a/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp b/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp
index a7173b1ad2a7..6f0146fdfe61 100644
--- a/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp
+++ b/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp
@@ -59,12 +59,12 @@ char *itostr2(const uint8_t &x) {
 }
 
 static void sendNewLine(void) {
-  ANYCUBIC_LCD_SERIAL.write('\r');
-  ANYCUBIC_LCD_SERIAL.write('\n');
+  LCD_SERIAL.write('\r');
+  LCD_SERIAL.write('\n');
 }
 
 static void send(const char *str) {
-  ANYCUBIC_LCD_SERIAL.print(str);
+  LCD_SERIAL.print(str);
 }
 
 static void sendLine(const char *str) {
@@ -74,7 +74,7 @@ static void sendLine(const char *str) {
 
 static void send_P(PGM_P str) {
   while (const char c = pgm_read_byte(str++))
-    ANYCUBIC_LCD_SERIAL.write(c);
+    LCD_SERIAL.write(c);
 }
 
 static void sendLine_P(PGM_P str) {
@@ -113,7 +113,7 @@ static void sendLine_P(PGM_P str) {
 AnycubicTFTClass::AnycubicTFTClass() {}
 
 void AnycubicTFTClass::OnSetup() {
-  ANYCUBIC_LCD_SERIAL.begin(115200);
+  LCD_SERIAL.begin(115200);
   SENDLINE_DBG_PGM("J17", "TFT Serial Debug: Main board reset... J17"); // J17 Main board reset
   ExtUI::delay_ms(10);
 
@@ -574,8 +574,8 @@ void AnycubicTFTClass::OnPrintTimerStopped() {
 
 void AnycubicTFTClass::GetCommandFromTFT() {
   char *starpos = NULL;
-  while (ANYCUBIC_LCD_SERIAL.available() > 0  && TFTbuflen < TFTBUFSIZE) {
-    serial3_char = ANYCUBIC_LCD_SERIAL.read();
+  while (LCD_SERIAL.available() > 0  && TFTbuflen < TFTBUFSIZE) {
+    serial3_char = LCD_SERIAL.read();
     if (serial3_char == '\n' ||
         serial3_char == '\r' ||
         serial3_char == ':'  ||
@@ -637,11 +637,11 @@ void AnycubicTFTClass::GetCommandFromTFT() {
             float yPostition = ExtUI::getAxisPosition_mm(ExtUI::Y);
             float zPostition = ExtUI::getAxisPosition_mm(ExtUI::Z);
             SEND_PGM("A5V X: ");
-            ANYCUBIC_LCD_SERIAL.print(xPostition);
+            LCD_SERIAL.print(xPostition);
             SEND_PGM(" Y: ");
-            ANYCUBIC_LCD_SERIAL.print(yPostition);
+            LCD_SERIAL.print(yPostition);
             SEND_PGM(" Z: ");
-            ANYCUBIC_LCD_SERIAL.print(zPostition);
+            LCD_SERIAL.print(zPostition);
             SENDLINE_PGM("");
           }
           break;
diff --git a/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp b/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp
index b788587c9412..340cb3dd8201 100644
--- a/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp
+++ b/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp
@@ -59,10 +59,8 @@ constexpr uint8_t DGUS_CMD_READVAR = 0x83;
   bool dguslcd_local_debug; // = false;
 #endif
 
-#define dgusserial DGUS_SERIAL
-
 void DGUSDisplay::InitDisplay() {
-  dgusserial.begin(DGUS_BAUDRATE);
+  LCD_SERIAL.begin(DGUS_BAUDRATE);
 
   if (true
     #if ENABLED(POWER_LOSS_RECOVERY)
@@ -89,7 +87,7 @@ void DGUSDisplay::WriteVariable(uint16_t adr, const void* values, uint8_t values
       strend = true;
       x = ' ';
     }
-    dgusserial.write(x);
+    LCD_SERIAL.write(x);
   }
 }
 
@@ -133,41 +131,41 @@ void DGUSDisplay::WriteVariablePGM(uint16_t adr, const void* values, uint8_t val
       strend = true;
       x = ' ';
     }
-    dgusserial.write(x);
+    LCD_SERIAL.write(x);
   }
 }
 
 void DGUSDisplay::ProcessRx() {
 
   #if ENABLED(DGUS_SERIAL_STATS_RX_BUFFER_OVERRUNS)
-    if (!dgusserial.available() && dgusserial.buffer_overruns()) {
+    if (!LCD_SERIAL.available() && LCD_SERIAL.buffer_overruns()) {
       // Overrun, but reset the flag only when the buffer is empty
       // We want to extract as many as valid datagrams possible...
       DEBUG_ECHOPGM("OVFL");
       rx_datagram_state = DGUS_IDLE;
-      //dgusserial.reset_rx_overun();
-      dgusserial.flush();
+      //LCD_SERIAL.reset_rx_overun();
+      LCD_SERIAL.flush();
     }
   #endif
 
   uint8_t receivedbyte;
-  while (dgusserial.available()) {
+  while (LCD_SERIAL.available()) {
     switch (rx_datagram_state) {
 
       case DGUS_IDLE: // Waiting for the first header byte
-        receivedbyte = dgusserial.read();
+        receivedbyte = LCD_SERIAL.read();
         //DEBUG_ECHOPAIR("< ",x);
         if (DGUS_HEADER1 == receivedbyte) rx_datagram_state = DGUS_HEADER1_SEEN;
         break;
 
       case DGUS_HEADER1_SEEN: // Waiting for the second header byte
-        receivedbyte = dgusserial.read();
+        receivedbyte = LCD_SERIAL.read();
         //DEBUG_ECHOPAIR(" ",x);
         rx_datagram_state = (DGUS_HEADER2 == receivedbyte) ? DGUS_HEADER2_SEEN : DGUS_IDLE;
         break;
 
       case DGUS_HEADER2_SEEN: // Waiting for the length byte
-        rx_datagram_len = dgusserial.read();
+        rx_datagram_len = LCD_SERIAL.read();
         DEBUG_ECHOPAIR(" (", rx_datagram_len, ") ");
 
         // Telegram min len is 3 (command and one word of payload)
@@ -175,10 +173,10 @@ void DGUSDisplay::ProcessRx() {
         break;
 
       case DGUS_WAIT_TELEGRAM: // wait for complete datagram to arrive.
-        if (dgusserial.available() < rx_datagram_len) return;
+        if (LCD_SERIAL.available() < rx_datagram_len) return;
 
         Initialized = true; // We've talked to it, so we defined it as initialized.
-        uint8_t command = dgusserial.read();
+        uint8_t command = LCD_SERIAL.read();
 
         DEBUG_ECHOPAIR("# ", command);
 
@@ -186,7 +184,7 @@ void DGUSDisplay::ProcessRx() {
         unsigned char tmp[rx_datagram_len - 1];
         unsigned char *ptmp = tmp;
         while (readlen--) {
-          receivedbyte = dgusserial.read();
+          receivedbyte = LCD_SERIAL.read();
           DEBUG_ECHOPAIR(" ", receivedbyte);
           *ptmp++ = receivedbyte;
         }
@@ -229,19 +227,19 @@ void DGUSDisplay::ProcessRx() {
   }
 }
 
-size_t DGUSDisplay::GetFreeTxBuffer() { return DGUS_SERIAL_GET_TX_BUFFER_FREE(); }
+size_t DGUSDisplay::GetFreeTxBuffer() { return SERIAL_GET_TX_BUFFER_FREE(); }
 
 void DGUSDisplay::WriteHeader(uint16_t adr, uint8_t cmd, uint8_t payloadlen) {
-  dgusserial.write(DGUS_HEADER1);
-  dgusserial.write(DGUS_HEADER2);
-  dgusserial.write(payloadlen + 3);
-  dgusserial.write(cmd);
-  dgusserial.write(adr >> 8);
-  dgusserial.write(adr & 0xFF);
+  LCD_SERIAL.write(DGUS_HEADER1);
+  LCD_SERIAL.write(DGUS_HEADER2);
+  LCD_SERIAL.write(payloadlen + 3);
+  LCD_SERIAL.write(cmd);
+  LCD_SERIAL.write(adr >> 8);
+  LCD_SERIAL.write(adr & 0xFF);
 }
 
 void DGUSDisplay::WritePGM(const char str[], uint8_t len) {
-  while (len--) dgusserial.write(pgm_read_byte(str++));
+  while (len--) LCD_SERIAL.write(pgm_read_byte(str++));
 }
 
 void DGUSDisplay::loop() {
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index 01b9a9c3ce4f..ece1b142355c 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -80,7 +80,7 @@ void write_to_lcd_P(PGM_P const message) {
   LOOP_L_N(i, message_length)
     encoded_message[i] = pgm_read_byte(&message[i]) | 0x80;
 
-  MALYAN_LCD_SERIAL.Print::write(encoded_message, message_length);
+  LCD_SERIAL.Print::write(encoded_message, message_length);
 }
 
 void write_to_lcd(const char * const message) {
@@ -90,7 +90,7 @@ void write_to_lcd(const char * const message) {
   LOOP_L_N(i, message_length)
     encoded_message[i] = message[i] | 0x80;
 
-  MALYAN_LCD_SERIAL.Print::write(encoded_message, message_length);
+  LCD_SERIAL.Print::write(encoded_message, message_length);
 }
 
 // {E:<msg>} is for error states.
@@ -428,7 +428,7 @@ namespace ExtUI {
      * it and translate into ExtUI operations where possible.
      */
     inbound_count = 0;
-    MALYAN_LCD_SERIAL.begin(500000);
+    LCD_SERIAL.begin(500000);
 
     // Signal init
     write_to_lcd_P(PSTR("{SYS:STARTED}\r\n"));
@@ -451,8 +451,8 @@ namespace ExtUI {
     update_usb_status(false);
 
     // now drain commands...
-    while (MALYAN_LCD_SERIAL.available())
-      parse_lcd_byte((byte)MALYAN_LCD_SERIAL.read());
+    while (LCD_SERIAL.available())
+      parse_lcd_byte((byte)LCD_SERIAL.read());
 
     #if ENABLED(SDSUPPORT)
       // The way last printing status works is simple:
diff --git a/buildroot/tests/malyan_M300-tests b/buildroot/tests/malyan_M300-tests
index 8b41114470eb..1955accaa5f6 100755
--- a/buildroot/tests/malyan_M300-tests
+++ b/buildroot/tests/malyan_M300-tests
@@ -9,7 +9,7 @@ set -e
 restore_configs
 use_example_configs "delta/Malyan M300"
 opt_disable AUTO_BED_LEVELING_3POINT
-opt_set MALYAN_LCD_SERIAL_PORT 1
+opt_set LCD_SERIAL_PORT 1
 exec_test $1 $2 "Malyan M300 (delta)"
 
 # cleanup

From a2641dcb6b6831cb34c57f957c716e760dcab56e Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 21:21:54 -0500
Subject: [PATCH 21/33] lcd baudrate

---
 Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp  |  5 ++++-
 .../anycubic_i3mega/anycubic_i3mega_lcd.cpp   | 12 ++++++-----
 Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp | 20 ++++++-------------
 .../extui/lib/mks_ui/printer_operation.cpp    |  6 +++---
 Marlin/src/lcd/extui/malyan_lcd.cpp           |  6 +++++-
 5 files changed, 25 insertions(+), 24 deletions(-)

diff --git a/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp b/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
index 96856c9e0b47..4a8095b6e993 100644
--- a/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
+++ b/Marlin/src/lcd/extui/anycubic_chiron_lcd.cpp
@@ -466,7 +466,10 @@ namespace ExtUI {
   }
 
   void onStartup() {
-    LCD_SERIAL.begin(115200);
+    #ifndef LCD_BAUDRATE
+      #define LCD_BAUDRATE 115200
+    #endif
+    LCD_SERIAL.begin(LCD_BAUDRATE);
     sendNewLine();
     SENDLINE_PGM("J17"); // Reset
     delay_ms(10);
diff --git a/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp b/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp
index 6f0146fdfe61..c69fb8351a74 100644
--- a/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp
+++ b/Marlin/src/lcd/extui/lib/anycubic_i3mega/anycubic_i3mega_lcd.cpp
@@ -113,18 +113,20 @@ static void sendLine_P(PGM_P str) {
 AnycubicTFTClass::AnycubicTFTClass() {}
 
 void AnycubicTFTClass::OnSetup() {
-  LCD_SERIAL.begin(115200);
+  #ifndef LCD_BAUDRATE
+    #define LCD_BAUDRATE 115200
+  #endif
+  LCD_SERIAL.begin(LCD_BAUDRATE);
+
   SENDLINE_DBG_PGM("J17", "TFT Serial Debug: Main board reset... J17"); // J17 Main board reset
   ExtUI::delay_ms(10);
 
   // initialise the state of the key pins running on the tft
   #if ENABLED(SDSUPPORT) && PIN_EXISTS(SD_DETECT)
-    pinMode(SD_DETECT_PIN, INPUT);
-    WRITE(SD_DETECT_PIN, HIGH);
+    SET_INPUT_PULLUP(SD_DETECT_PIN);
   #endif
   #if ENABLED(FILAMENT_RUNOUT_SENSOR)
-    pinMode(FIL_RUNOUT_PIN, INPUT);
-    WRITE(FIL_RUNOUT_PIN, HIGH);
+    SET_INPUT_PULLUP(FIL_RUNOUT_PIN);
   #endif
 
   mediaPrintingState = AMPRINTSTATE_NOT_PRINTING;
diff --git a/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp b/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp
index 340cb3dd8201..5181ba7cc454 100644
--- a/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp
+++ b/Marlin/src/lcd/extui/lib/dgus/DGUSDisplay.cpp
@@ -60,20 +60,12 @@ constexpr uint8_t DGUS_CMD_READVAR = 0x83;
 #endif
 
 void DGUSDisplay::InitDisplay() {
-  LCD_SERIAL.begin(DGUS_BAUDRATE);
-
-  if (true
-    #if ENABLED(POWER_LOSS_RECOVERY)
-      && !recovery.valid()
-    #endif
-  )
-    RequestScreen(
-      #if ENABLED(SHOW_BOOTSCREEN)
-        DGUSLCD_SCREEN_BOOT
-      #else
-        DGUSLCD_SCREEN_MAIN
-      #endif
-    );
+  #ifndef LCD_BAUDRATE
+    #define LCD_BAUDRATE 115200
+  #endif
+  LCD_SERIAL.begin(LCD_BAUDRATE);
+  if (TERN1(POWER_LOSS_RECOVERY, !recovery.valid()))
+    RequestScreen(TERN(SHOW_BOOTSCREEN, DGUSLCD_SCREEN_BOOT, DGUSLCD_SCREEN_MAIN));
 }
 
 void DGUSDisplay::WriteVariable(uint16_t adr, const void* values, uint8_t valueslen, bool isstr) {
diff --git a/Marlin/src/lcd/extui/lib/mks_ui/printer_operation.cpp b/Marlin/src/lcd/extui/lib/mks_ui/printer_operation.cpp
index 0e4526734ca1..2b6f5f89f6ee 100644
--- a/Marlin/src/lcd/extui/lib/mks_ui/printer_operation.cpp
+++ b/Marlin/src/lcd/extui/lib/mks_ui/printer_operation.cpp
@@ -161,13 +161,13 @@ void printer_state_polling() {
 
 void filament_pin_setup() {
   #if PIN_EXISTS(MT_DET_1)
-    pinMode(MT_DET_1_PIN, INPUT_PULLUP);
+    SET_INPUT_PULLUP(MT_DET_1_PIN);
   #endif
   #if PIN_EXISTS(MT_DET_2)
-    pinMode(MT_DET_2_PIN, INPUT_PULLUP);
+    SET_INPUT_PULLUP(MT_DET_2_PIN);
   #endif
   #if PIN_EXISTS(MT_DET_3)
-    pinMode(MT_DET_3_PIN, INPUT_PULLUP);
+    SET_INPUT_PULLUP(MT_DET_3_PIN);
   #endif
 }
 
diff --git a/Marlin/src/lcd/extui/malyan_lcd.cpp b/Marlin/src/lcd/extui/malyan_lcd.cpp
index ece1b142355c..79a5fb961aa1 100644
--- a/Marlin/src/lcd/extui/malyan_lcd.cpp
+++ b/Marlin/src/lcd/extui/malyan_lcd.cpp
@@ -428,7 +428,11 @@ namespace ExtUI {
      * it and translate into ExtUI operations where possible.
      */
     inbound_count = 0;
-    LCD_SERIAL.begin(500000);
+
+    #ifndef LCD_BAUDRATE
+      #define LCD_BAUDRATE 500000
+    #endif
+    LCD_SERIAL.begin(LCD_BAUDRATE);
 
     // Signal init
     write_to_lcd_P(PSTR("{SYS:STARTED}\r\n"));

From 69c6c3d71535dad0ddd6f149c12a03ecabf80fdf Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 21:26:06 -0500
Subject: [PATCH 22/33] Serial fixes

---
 Marlin/src/HAL/AVR/HAL.h         | 1 -
 Marlin/src/HAL/SAMD51/HAL.h      | 4 ++--
 Marlin/src/HAL/TEENSY40_41/HAL.h | 2 +-
 3 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/Marlin/src/HAL/AVR/HAL.h b/Marlin/src/HAL/AVR/HAL.h
index 790ad872ac0b..41f1acd32f68 100644
--- a/Marlin/src/HAL/AVR/HAL.h
+++ b/Marlin/src/HAL/AVR/HAL.h
@@ -86,7 +86,6 @@ typedef int8_t pin_t;
   #if !WITHIN(SERIAL_PORT, -1, 3)
     #error "SERIAL_PORT must be from -1 to 3. Please update your configuration."
   #endif
-
   #define MYSERIAL0 customizedSerial1
 
   #ifdef SERIAL_PORT_2
diff --git a/Marlin/src/HAL/SAMD51/HAL.h b/Marlin/src/HAL/SAMD51/HAL.h
index 7b532cd59816..7fd826a1b6a4 100644
--- a/Marlin/src/HAL/SAMD51/HAL.h
+++ b/Marlin/src/HAL/SAMD51/HAL.h
@@ -50,7 +50,7 @@
     #if SERIAL_PORT_2 == -1
       #define MYSERIAL1 Serial
     #elif WITHIN(SERIAL_PORT_2, 0, 3)
-      #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
+      #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
     #else
       #error "SERIAL_PORT_2 must be from -1 to 3. Please update your configuration."
     #endif
@@ -60,7 +60,7 @@
     #if LCD_SERIAL_PORT == -1
       #define LCD_SERIAL Serial
     #elif WITHIN(LCD_SERIAL_PORT, 0, 3)
-      #define MYSERIAL0 MSERIAL(LCD_SERIAL_PORT)
+      #define LCD_SERIAL MSERIAL(LCD_SERIAL_PORT)
     #else
       #error "LCD_SERIAL_PORT must be from -1 to 3. Please update your configuration."
     #endif
diff --git a/Marlin/src/HAL/TEENSY40_41/HAL.h b/Marlin/src/HAL/TEENSY40_41/HAL.h
index 77f7af295668..b3b0144d134b 100644
--- a/Marlin/src/HAL/TEENSY40_41/HAL.h
+++ b/Marlin/src/HAL/TEENSY40_41/HAL.h
@@ -66,7 +66,7 @@
   #if SERIAL_PORT_2 == -1
     #define MYSERIAL1 usbSerial
   #elif WITHIN(SERIAL_PORT_2, 0, 8)
-    #define MYSERIAL0 MSERIAL(SERIAL_PORT_2)
+    #define MYSERIAL1 MSERIAL(SERIAL_PORT_2)
   #else
       #error "SERIAL_PORT_2 must be from -1 to 8. Please update your configuration."
   #endif

From 824d31ace52c595f08157e8ec8cfcca4dca8702c Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 21:39:11 -0500
Subject: [PATCH 23/33] better

---
 Marlin/src/HAL/AVR/MarlinSerial.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/src/HAL/AVR/MarlinSerial.h b/Marlin/src/HAL/AVR/MarlinSerial.h
index 3d581cac4bb9..6197308bb014 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.h
+++ b/Marlin/src/HAL/AVR/MarlinSerial.h
@@ -217,7 +217,7 @@
       static ring_buffer_pos_t available();
       static void write(const uint8_t c);
       static void flushTX();
-      #ifdef LCD_SERIAL_PORT
+      #if HAS_DGUS_LCD
         static ring_buffer_pos_t get_tx_buffer_free();
       #endif
 

From ab550c8b2f5836311c6e9a5dc3909ee378e40a00 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 21:52:20 -0500
Subject: [PATCH 24/33] Shift MarlinSerial left

---
 Marlin/src/HAL/AVR/MarlinSerial.cpp | 1172 +++++++++++++--------------
 1 file changed, 586 insertions(+), 586 deletions(-)

diff --git a/Marlin/src/HAL/AVR/MarlinSerial.cpp b/Marlin/src/HAL/AVR/MarlinSerial.cpp
index 4d654c0d8082..63599efd4132 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.cpp
+++ b/Marlin/src/HAL/AVR/MarlinSerial.cpp
@@ -40,407 +40,370 @@
 
 #if !defined(USBCON) && (defined(UBRRH) || defined(UBRR0H) || defined(UBRR1H) || defined(UBRR2H) || defined(UBRR3H))
 
-  #include "MarlinSerial.h"
-  #include "../../MarlinCore.h"
+#include "MarlinSerial.h"
+#include "../../MarlinCore.h"
+
+#if ENABLED(DIRECT_STEPPING)
+  #include "../../feature/direct_stepping.h"
+#endif
+
+template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_r MarlinSerial<Cfg>::rx_buffer = { 0, 0, { 0 } };
+template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_t MarlinSerial<Cfg>::tx_buffer = { 0 };
+template<typename Cfg> bool     MarlinSerial<Cfg>::_written = false;
+template<typename Cfg> uint8_t  MarlinSerial<Cfg>::xon_xoff_state = MarlinSerial<Cfg>::XON_XOFF_CHAR_SENT | MarlinSerial<Cfg>::XON_CHAR;
+template<typename Cfg> uint8_t  MarlinSerial<Cfg>::rx_dropped_bytes = 0;
+template<typename Cfg> uint8_t  MarlinSerial<Cfg>::rx_buffer_overruns = 0;
+template<typename Cfg> uint8_t  MarlinSerial<Cfg>::rx_framing_errors = 0;
+template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::rx_max_enqueued = 0;
+
+// A SW memory barrier, to ensure GCC does not overoptimize loops
+#define sw_barrier() asm volatile("": : :"memory");
+
+#include "../../feature/e_parser.h"
+
+// "Atomically" read the RX head index value without disabling interrupts:
+// This MUST be called with RX interrupts enabled, and CAN'T be called
+// from the RX ISR itself!
+template<typename Cfg>
+FORCE_INLINE typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::atomic_read_rx_head() {
+  if (Cfg::RX_SIZE > 256) {
+    // Keep reading until 2 consecutive reads return the same value,
+    // meaning there was no update in-between caused by an interrupt.
+    // This works because serial RX interrupts happen at a slower rate
+    // than successive reads of a variable, so 2 consecutive reads with
+    // the same value means no interrupt updated it.
+    ring_buffer_pos_t vold, vnew = rx_buffer.head;
+    sw_barrier();
+    do {
+      vold = vnew;
+      vnew = rx_buffer.head;
+      sw_barrier();
+    } while (vold != vnew);
+    return vnew;
+  }
+  else {
+    // With an 8bit index, reads are always atomic. No need for special handling
+    return rx_buffer.head;
+  }
+}
+
+template<typename Cfg>
+volatile bool MarlinSerial<Cfg>::rx_tail_value_not_stable = false;
+template<typename Cfg>
+volatile uint16_t MarlinSerial<Cfg>::rx_tail_value_backup = 0;
+
+// Set RX tail index, taking into account the RX ISR could interrupt
+//  the write to this variable in the middle - So a backup strategy
+//  is used to ensure reads of the correct values.
+//    -Must NOT be called from the RX ISR -
+template<typename Cfg>
+FORCE_INLINE void MarlinSerial<Cfg>::atomic_set_rx_tail(typename MarlinSerial<Cfg>::ring_buffer_pos_t value) {
+  if (Cfg::RX_SIZE > 256) {
+    // Store the new value in the backup
+    rx_tail_value_backup = value;
+    sw_barrier();
+    // Flag we are about to change the true value
+    rx_tail_value_not_stable = true;
+    sw_barrier();
+    // Store the new value
+    rx_buffer.tail = value;
+    sw_barrier();
+    // Signal the new value is completely stored into the value
+    rx_tail_value_not_stable = false;
+    sw_barrier();
+  }
+  else
+    rx_buffer.tail = value;
+}
+
+// Get the RX tail index, taking into account the read could be
+//  interrupting in the middle of the update of that index value
+//    -Called from the RX ISR -
+template<typename Cfg>
+FORCE_INLINE typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::atomic_read_rx_tail() {
+  if (Cfg::RX_SIZE > 256) {
+    // If the true index is being modified, return the backup value
+    if (rx_tail_value_not_stable) return rx_tail_value_backup;
+  }
+  // The true index is stable, return it
+  return rx_buffer.tail;
+}
+
+// (called with RX interrupts disabled)
+template<typename Cfg>
+FORCE_INLINE void MarlinSerial<Cfg>::store_rxd_char() {
+
+  static EmergencyParser::State emergency_state; // = EP_RESET
+
+  // This must read the R_UCSRA register before reading the received byte to detect error causes
+  if (Cfg::DROPPED_RX && B_DOR && !++rx_dropped_bytes) --rx_dropped_bytes;
+  if (Cfg::RX_OVERRUNS && B_DOR && !++rx_buffer_overruns) --rx_buffer_overruns;
+  if (Cfg::RX_FRAMING_ERRORS && B_FE && !++rx_framing_errors) --rx_framing_errors;
+
+  // Read the character from the USART
+  uint8_t c = R_UDR;
 
   #if ENABLED(DIRECT_STEPPING)
-    #include "../../feature/direct_stepping.h"
+    if (page_manager.maybe_store_rxd_char(c)) return;
   #endif
 
-  template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_r MarlinSerial<Cfg>::rx_buffer = { 0, 0, { 0 } };
-  template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_t MarlinSerial<Cfg>::tx_buffer = { 0 };
-  template<typename Cfg> bool     MarlinSerial<Cfg>::_written = false;
-  template<typename Cfg> uint8_t  MarlinSerial<Cfg>::xon_xoff_state = MarlinSerial<Cfg>::XON_XOFF_CHAR_SENT | MarlinSerial<Cfg>::XON_CHAR;
-  template<typename Cfg> uint8_t  MarlinSerial<Cfg>::rx_dropped_bytes = 0;
-  template<typename Cfg> uint8_t  MarlinSerial<Cfg>::rx_buffer_overruns = 0;
-  template<typename Cfg> uint8_t  MarlinSerial<Cfg>::rx_framing_errors = 0;
-  template<typename Cfg> typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::rx_max_enqueued = 0;
-
-  // A SW memory barrier, to ensure GCC does not overoptimize loops
-  #define sw_barrier() asm volatile("": : :"memory");
-
-  #include "../../feature/e_parser.h"
-
-  // "Atomically" read the RX head index value without disabling interrupts:
-  // This MUST be called with RX interrupts enabled, and CAN'T be called
-  // from the RX ISR itself!
-  template<typename Cfg>
-  FORCE_INLINE typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::atomic_read_rx_head() {
-    if (Cfg::RX_SIZE > 256) {
-      // Keep reading until 2 consecutive reads return the same value,
-      // meaning there was no update in-between caused by an interrupt.
-      // This works because serial RX interrupts happen at a slower rate
-      // than successive reads of a variable, so 2 consecutive reads with
-      // the same value means no interrupt updated it.
-      ring_buffer_pos_t vold, vnew = rx_buffer.head;
-      sw_barrier();
-      do {
-        vold = vnew;
-        vnew = rx_buffer.head;
-        sw_barrier();
-      } while (vold != vnew);
-      return vnew;
-    }
-    else {
-      // With an 8bit index, reads are always atomic. No need for special handling
-      return rx_buffer.head;
-    }
-  }
+  // Get the tail - Nothing can alter its value while this ISR is executing, but there's
+  // a chance that this ISR interrupted the main process while it was updating the index.
+  // The backup mechanism ensures the correct value is always returned.
+  const ring_buffer_pos_t t = atomic_read_rx_tail();
 
-  template<typename Cfg>
-  volatile bool MarlinSerial<Cfg>::rx_tail_value_not_stable = false;
-  template<typename Cfg>
-  volatile uint16_t MarlinSerial<Cfg>::rx_tail_value_backup = 0;
-
-  // Set RX tail index, taking into account the RX ISR could interrupt
-  //  the write to this variable in the middle - So a backup strategy
-  //  is used to ensure reads of the correct values.
-  //    -Must NOT be called from the RX ISR -
-  template<typename Cfg>
-  FORCE_INLINE void MarlinSerial<Cfg>::atomic_set_rx_tail(typename MarlinSerial<Cfg>::ring_buffer_pos_t value) {
-    if (Cfg::RX_SIZE > 256) {
-      // Store the new value in the backup
-      rx_tail_value_backup = value;
-      sw_barrier();
-      // Flag we are about to change the true value
-      rx_tail_value_not_stable = true;
-      sw_barrier();
-      // Store the new value
-      rx_buffer.tail = value;
-      sw_barrier();
-      // Signal the new value is completely stored into the value
-      rx_tail_value_not_stable = false;
-      sw_barrier();
-    }
-    else
-      rx_buffer.tail = value;
-  }
+  // Get the head pointer - This ISR is the only one that modifies its value, so it's safe to read here
+  ring_buffer_pos_t h = rx_buffer.head;
 
-  // Get the RX tail index, taking into account the read could be
-  //  interrupting in the middle of the update of that index value
-  //    -Called from the RX ISR -
-  template<typename Cfg>
-  FORCE_INLINE typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::atomic_read_rx_tail() {
-    if (Cfg::RX_SIZE > 256) {
-      // If the true index is being modified, return the backup value
-      if (rx_tail_value_not_stable) return rx_tail_value_backup;
-    }
-    // The true index is stable, return it
-    return rx_buffer.tail;
-  }
+  // Get the next element
+  ring_buffer_pos_t i = (ring_buffer_pos_t)(h + 1) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
 
-  // (called with RX interrupts disabled)
-  template<typename Cfg>
-  FORCE_INLINE void MarlinSerial<Cfg>::store_rxd_char() {
+  if (Cfg::EMERGENCYPARSER) emergency_parser.update(emergency_state, c);
 
-    static EmergencyParser::State emergency_state; // = EP_RESET
+  // If the character is to be stored at the index just before the tail
+  // (such that the head would advance to the current tail), the RX FIFO is
+  // full, so don't write the character or advance the head.
+  if (i != t) {
+    rx_buffer.buffer[h] = c;
+    h = i;
+  }
+  else if (Cfg::DROPPED_RX && !++rx_dropped_bytes)
+    --rx_dropped_bytes;
 
-    // This must read the R_UCSRA register before reading the received byte to detect error causes
-    if (Cfg::DROPPED_RX && B_DOR && !++rx_dropped_bytes) --rx_dropped_bytes;
-    if (Cfg::RX_OVERRUNS && B_DOR && !++rx_buffer_overruns) --rx_buffer_overruns;
-    if (Cfg::RX_FRAMING_ERRORS && B_FE && !++rx_framing_errors) --rx_framing_errors;
+  if (Cfg::MAX_RX_QUEUED) {
+    // Calculate count of bytes stored into the RX buffer
+    const ring_buffer_pos_t rx_count = (ring_buffer_pos_t)(h - t) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
 
-    // Read the character from the USART
-    uint8_t c = R_UDR;
+    // Keep track of the maximum count of enqueued bytes
+    NOLESS(rx_max_enqueued, rx_count);
+  }
 
-    #if ENABLED(DIRECT_STEPPING)
-      if (page_manager.maybe_store_rxd_char(c)) return;
-    #endif
+  if (Cfg::XONOFF) {
+    // If the last char that was sent was an XON
+    if ((xon_xoff_state & XON_XOFF_CHAR_MASK) == XON_CHAR) {
 
-    // Get the tail - Nothing can alter its value while this ISR is executing, but there's
-    // a chance that this ISR interrupted the main process while it was updating the index.
-    // The backup mechanism ensures the correct value is always returned.
-    const ring_buffer_pos_t t = atomic_read_rx_tail();
+      // Bytes stored into the RX buffer
+      const ring_buffer_pos_t rx_count = (ring_buffer_pos_t)(h - t) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
 
-    // Get the head pointer - This ISR is the only one that modifies its value, so it's safe to read here
-    ring_buffer_pos_t h = rx_buffer.head;
+      // If over 12.5% of RX buffer capacity, send XOFF before running out of
+      // RX buffer space .. 325 bytes @ 250kbits/s needed to let the host react
+      // and stop sending bytes. This translates to 13mS propagation time.
+      if (rx_count >= (Cfg::RX_SIZE) / 8) {
 
-    // Get the next element
-    ring_buffer_pos_t i = (ring_buffer_pos_t)(h + 1) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
+        // At this point, definitely no TX interrupt was executing, since the TX ISR can't be preempted.
+        // Don't enable the TX interrupt here as a means to trigger the XOFF char, because if it happens
+        // to be in the middle of trying to disable the RX interrupt in the main program, eventually the
+        // enabling of the TX interrupt could be undone. The ONLY reliable thing this can do to ensure
+        // the sending of the XOFF char is to send it HERE AND NOW.
 
-    if (Cfg::EMERGENCYPARSER) emergency_parser.update(emergency_state, c);
+        // About to send the XOFF char
+        xon_xoff_state = XOFF_CHAR | XON_XOFF_CHAR_SENT;
 
-    // If the character is to be stored at the index just before the tail
-    // (such that the head would advance to the current tail), the RX FIFO is
-    // full, so don't write the character or advance the head.
-    if (i != t) {
-      rx_buffer.buffer[h] = c;
-      h = i;
-    }
-    else if (Cfg::DROPPED_RX && !++rx_dropped_bytes)
-      --rx_dropped_bytes;
+        // Wait until the TX register becomes empty and send it - Here there could be a problem
+        // - While waiting for the TX register to empty, the RX register could receive a new
+        //   character. This must also handle that situation!
+        while (!B_UDRE) {
 
-    if (Cfg::MAX_RX_QUEUED) {
-      // Calculate count of bytes stored into the RX buffer
-      const ring_buffer_pos_t rx_count = (ring_buffer_pos_t)(h - t) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
+          if (B_RXC) {
+            // A char arrived while waiting for the TX buffer to be empty - Receive and process it!
 
-      // Keep track of the maximum count of enqueued bytes
-      NOLESS(rx_max_enqueued, rx_count);
-    }
+            i = (ring_buffer_pos_t)(h + 1) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
 
-    if (Cfg::XONOFF) {
-      // If the last char that was sent was an XON
-      if ((xon_xoff_state & XON_XOFF_CHAR_MASK) == XON_CHAR) {
-
-        // Bytes stored into the RX buffer
-        const ring_buffer_pos_t rx_count = (ring_buffer_pos_t)(h - t) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
-
-        // If over 12.5% of RX buffer capacity, send XOFF before running out of
-        // RX buffer space .. 325 bytes @ 250kbits/s needed to let the host react
-        // and stop sending bytes. This translates to 13mS propagation time.
-        if (rx_count >= (Cfg::RX_SIZE) / 8) {
-
-          // At this point, definitely no TX interrupt was executing, since the TX ISR can't be preempted.
-          // Don't enable the TX interrupt here as a means to trigger the XOFF char, because if it happens
-          // to be in the middle of trying to disable the RX interrupt in the main program, eventually the
-          // enabling of the TX interrupt could be undone. The ONLY reliable thing this can do to ensure
-          // the sending of the XOFF char is to send it HERE AND NOW.
-
-          // About to send the XOFF char
-          xon_xoff_state = XOFF_CHAR | XON_XOFF_CHAR_SENT;
-
-          // Wait until the TX register becomes empty and send it - Here there could be a problem
-          // - While waiting for the TX register to empty, the RX register could receive a new
-          //   character. This must also handle that situation!
-          while (!B_UDRE) {
-
-            if (B_RXC) {
-              // A char arrived while waiting for the TX buffer to be empty - Receive and process it!
-
-              i = (ring_buffer_pos_t)(h + 1) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
-
-              // Read the character from the USART
-              c = R_UDR;
-
-              if (Cfg::EMERGENCYPARSER) emergency_parser.update(emergency_state, c);
-
-              // If the character is to be stored at the index just before the tail
-              // (such that the head would advance to the current tail), the FIFO is
-              // full, so don't write the character or advance the head.
-              if (i != t) {
-                rx_buffer.buffer[h] = c;
-                h = i;
-              }
-              else if (Cfg::DROPPED_RX && !++rx_dropped_bytes)
-                --rx_dropped_bytes;
-            }
-            sw_barrier();
-          }
+            // Read the character from the USART
+            c = R_UDR;
+
+            if (Cfg::EMERGENCYPARSER) emergency_parser.update(emergency_state, c);
 
-          R_UDR = XOFF_CHAR;
-
-          // Clear the TXC bit -- "can be cleared by writing a one to its bit
-          // location". This makes sure flush() won't return until the bytes
-          // actually got written
-          B_TXC = 1;
-
-          // At this point there could be a race condition between the write() function
-          // and this sending of the XOFF char. This interrupt could happen between the
-          // wait to be empty TX buffer loop and the actual write of the character. Since
-          // the TX buffer is full because it's sending the XOFF char, the only way to be
-          // sure the write() function will succeed is to wait for the XOFF char to be
-          // completely sent. Since an extra character could be received during the wait
-          // it must also be handled!
-          while (!B_UDRE) {
-
-            if (B_RXC) {
-              // A char arrived while waiting for the TX buffer to be empty - Receive and process it!
-
-              i = (ring_buffer_pos_t)(h + 1) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
-
-              // Read the character from the USART
-              c = R_UDR;
-
-              if (Cfg::EMERGENCYPARSER)
-                emergency_parser.update(emergency_state, c);
-
-              // If the character is to be stored at the index just before the tail
-              // (such that the head would advance to the current tail), the FIFO is
-              // full, so don't write the character or advance the head.
-              if (i != t) {
-                rx_buffer.buffer[h] = c;
-                h = i;
-              }
-              else if (Cfg::DROPPED_RX && !++rx_dropped_bytes)
-                --rx_dropped_bytes;
+            // If the character is to be stored at the index just before the tail
+            // (such that the head would advance to the current tail), the FIFO is
+            // full, so don't write the character or advance the head.
+            if (i != t) {
+              rx_buffer.buffer[h] = c;
+              h = i;
             }
-            sw_barrier();
+            else if (Cfg::DROPPED_RX && !++rx_dropped_bytes)
+              --rx_dropped_bytes;
           }
-
-          // At this point everything is ready. The write() function won't
-          // have any issues writing to the UART TX register if it needs to!
+          sw_barrier();
         }
-      }
-    }
 
-    // Store the new head value - The main loop will retry until the value is stable
-    rx_buffer.head = h;
-  }
+        R_UDR = XOFF_CHAR;
 
-  // (called with TX irqs disabled)
-  template<typename Cfg>
-  FORCE_INLINE void MarlinSerial<Cfg>::_tx_udr_empty_irq() {
-    if (Cfg::TX_SIZE > 0) {
-      // Read positions
-      uint8_t t = tx_buffer.tail;
-      const uint8_t h = tx_buffer.head;
+        // Clear the TXC bit -- "can be cleared by writing a one to its bit
+        // location". This makes sure flush() won't return until the bytes
+        // actually got written
+        B_TXC = 1;
 
-      if (Cfg::XONOFF) {
-        // If an XON char is pending to be sent, do it now
-        if (xon_xoff_state == XON_CHAR) {
+        // At this point there could be a race condition between the write() function
+        // and this sending of the XOFF char. This interrupt could happen between the
+        // wait to be empty TX buffer loop and the actual write of the character. Since
+        // the TX buffer is full because it's sending the XOFF char, the only way to be
+        // sure the write() function will succeed is to wait for the XOFF char to be
+        // completely sent. Since an extra character could be received during the wait
+        // it must also be handled!
+        while (!B_UDRE) {
 
-          // Send the character
-          R_UDR = XON_CHAR;
+          if (B_RXC) {
+            // A char arrived while waiting for the TX buffer to be empty - Receive and process it!
 
-          // clear the TXC bit -- "can be cleared by writing a one to its bit
-          // location". This makes sure flush() won't return until the bytes
-          // actually got written
-          B_TXC = 1;
+            i = (ring_buffer_pos_t)(h + 1) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
 
-          // Remember we sent it.
-          xon_xoff_state = XON_CHAR | XON_XOFF_CHAR_SENT;
+            // Read the character from the USART
+            c = R_UDR;
 
-          // If nothing else to transmit, just disable TX interrupts.
-          if (h == t) B_UDRIE = 0; // (Non-atomic, could be reenabled by the main program, but eventually this will succeed)
+            if (Cfg::EMERGENCYPARSER)
+              emergency_parser.update(emergency_state, c);
 
-          return;
+            // If the character is to be stored at the index just before the tail
+            // (such that the head would advance to the current tail), the FIFO is
+            // full, so don't write the character or advance the head.
+            if (i != t) {
+              rx_buffer.buffer[h] = c;
+              h = i;
+            }
+            else if (Cfg::DROPPED_RX && !++rx_dropped_bytes)
+              --rx_dropped_bytes;
+          }
+          sw_barrier();
         }
-      }
 
-      // If nothing to transmit, just disable TX interrupts. This could
-      // happen as the result of the non atomicity of the disabling of RX
-      // interrupts that could end reenabling TX interrupts as a side effect.
-      if (h == t) {
-        B_UDRIE = 0; // (Non-atomic, could be reenabled by the main program, but eventually this will succeed)
-        return;
+        // At this point everything is ready. The write() function won't
+        // have any issues writing to the UART TX register if it needs to!
       }
-
-      // There is something to TX, Send the next byte
-      const uint8_t c = tx_buffer.buffer[t];
-      t = (t + 1) & (Cfg::TX_SIZE - 1);
-      R_UDR = c;
-      tx_buffer.tail = t;
-
-      // Clear the TXC bit (by writing a one to its bit location).
-      // Ensures flush() won't return until the bytes are actually written/
-      B_TXC = 1;
-
-      // Disable interrupts if there is nothing to transmit following this byte
-      if (h == t) B_UDRIE = 0; // (Non-atomic, could be reenabled by the main program, but eventually this will succeed)
     }
   }
 
-  // Public Methods
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::begin(const long baud) {
-    uint16_t baud_setting;
-    bool useU2X = true;
-
-    #if F_CPU == 16000000UL && SERIAL_PORT == 0
-      // Hard-coded exception for compatibility with the bootloader shipped
-      // with the Duemilanove and previous boards, and the firmware on the
-      // 8U2 on the Uno and Mega 2560.
-      if (baud == 57600) useU2X = false;
-    #endif
-
-    R_UCSRA = 0;
-    if (useU2X) {
-      B_U2X = 1;
-      baud_setting = (F_CPU / 4 / baud - 1) / 2;
-    }
-    else
-      baud_setting = (F_CPU / 8 / baud - 1) / 2;
-
-    // assign the baud_setting, a.k.a. ubbr (USART Baud Rate Register)
-    R_UBRRH = baud_setting >> 8;
-    R_UBRRL = baud_setting;
-
-    B_RXEN = 1;
-    B_TXEN = 1;
-    B_RXCIE = 1;
-    if (Cfg::TX_SIZE > 0) B_UDRIE = 0;
-    _written = false;
-  }
+  // Store the new head value - The main loop will retry until the value is stable
+  rx_buffer.head = h;
+}
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::end() {
-    B_RXEN = 0;
-    B_TXEN = 0;
-    B_RXCIE = 0;
-    B_UDRIE = 0;
-  }
+// (called with TX irqs disabled)
+template<typename Cfg>
+FORCE_INLINE void MarlinSerial<Cfg>::_tx_udr_empty_irq() {
+  if (Cfg::TX_SIZE > 0) {
+    // Read positions
+    uint8_t t = tx_buffer.tail;
+    const uint8_t h = tx_buffer.head;
 
-  template<typename Cfg>
-  int MarlinSerial<Cfg>::peek() {
-    const ring_buffer_pos_t h = atomic_read_rx_head(), t = rx_buffer.tail;
-    return h == t ? -1 : rx_buffer.buffer[t];
-  }
-
-  template<typename Cfg>
-  int MarlinSerial<Cfg>::read() {
-    const ring_buffer_pos_t h = atomic_read_rx_head();
+    if (Cfg::XONOFF) {
+      // If an XON char is pending to be sent, do it now
+      if (xon_xoff_state == XON_CHAR) {
 
-    // Read the tail. Main thread owns it, so it is safe to directly read it
-    ring_buffer_pos_t t = rx_buffer.tail;
+        // Send the character
+        R_UDR = XON_CHAR;
 
-    // If nothing to read, return now
-    if (h == t) return -1;
+        // clear the TXC bit -- "can be cleared by writing a one to its bit
+        // location". This makes sure flush() won't return until the bytes
+        // actually got written
+        B_TXC = 1;
 
-    // Get the next char
-    const int v = rx_buffer.buffer[t];
-    t = (ring_buffer_pos_t)(t + 1) & (Cfg::RX_SIZE - 1);
+        // Remember we sent it.
+        xon_xoff_state = XON_CHAR | XON_XOFF_CHAR_SENT;
 
-    // Advance tail - Making sure the RX ISR will always get an stable value, even
-    // if it interrupts the writing of the value of that variable in the middle.
-    atomic_set_rx_tail(t);
+        // If nothing else to transmit, just disable TX interrupts.
+        if (h == t) B_UDRIE = 0; // (Non-atomic, could be reenabled by the main program, but eventually this will succeed)
 
-    if (Cfg::XONOFF) {
-      // If the XOFF char was sent, or about to be sent...
-      if ((xon_xoff_state & XON_XOFF_CHAR_MASK) == XOFF_CHAR) {
-        // Get count of bytes in the RX buffer
-        const ring_buffer_pos_t rx_count = (ring_buffer_pos_t)(h - t) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
-        if (rx_count < (Cfg::RX_SIZE) / 10) {
-          if (Cfg::TX_SIZE > 0) {
-            // Signal we want an XON character to be sent.
-            xon_xoff_state = XON_CHAR;
-            // Enable TX ISR. Non atomic, but it will eventually enable them
-            B_UDRIE = 1;
-          }
-          else {
-            // If not using TX interrupts, we must send the XON char now
-            xon_xoff_state = XON_CHAR | XON_XOFF_CHAR_SENT;
-            while (!B_UDRE) sw_barrier();
-            R_UDR = XON_CHAR;
-          }
-        }
+        return;
       }
     }
 
-    return v;
-  }
+    // If nothing to transmit, just disable TX interrupts. This could
+    // happen as the result of the non atomicity of the disabling of RX
+    // interrupts that could end reenabling TX interrupts as a side effect.
+    if (h == t) {
+      B_UDRIE = 0; // (Non-atomic, could be reenabled by the main program, but eventually this will succeed)
+      return;
+    }
+
+    // There is something to TX, Send the next byte
+    const uint8_t c = tx_buffer.buffer[t];
+    t = (t + 1) & (Cfg::TX_SIZE - 1);
+    R_UDR = c;
+    tx_buffer.tail = t;
 
-  template<typename Cfg>
-  typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::available() {
-    const ring_buffer_pos_t h = atomic_read_rx_head(), t = rx_buffer.tail;
-    return (ring_buffer_pos_t)(Cfg::RX_SIZE + h - t) & (Cfg::RX_SIZE - 1);
+    // Clear the TXC bit (by writing a one to its bit location).
+    // Ensures flush() won't return until the bytes are actually written/
+    B_TXC = 1;
+
+    // Disable interrupts if there is nothing to transmit following this byte
+    if (h == t) B_UDRIE = 0; // (Non-atomic, could be reenabled by the main program, but eventually this will succeed)
   }
+}
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::flush() {
+// Public Methods
+template<typename Cfg>
+void MarlinSerial<Cfg>::begin(const long baud) {
+  uint16_t baud_setting;
+  bool useU2X = true;
 
-    // Set the tail to the head:
-    //  - Read the RX head index in a safe way. (See atomic_read_rx_head.)
-    //  - Set the tail, making sure the RX ISR will always get a stable value, even
-    //    if it interrupts the writing of the value of that variable in the middle.
-    atomic_set_rx_tail(atomic_read_rx_head());
+  #if F_CPU == 16000000UL && SERIAL_PORT == 0
+    // Hard-coded exception for compatibility with the bootloader shipped
+    // with the Duemilanove and previous boards, and the firmware on the
+    // 8U2 on the Uno and Mega 2560.
+    if (baud == 57600) useU2X = false;
+  #endif
 
-    if (Cfg::XONOFF) {
-      // If the XOFF char was sent, or about to be sent...
-      if ((xon_xoff_state & XON_XOFF_CHAR_MASK) == XOFF_CHAR) {
+  R_UCSRA = 0;
+  if (useU2X) {
+    B_U2X = 1;
+    baud_setting = (F_CPU / 4 / baud - 1) / 2;
+  }
+  else
+    baud_setting = (F_CPU / 8 / baud - 1) / 2;
+
+  // assign the baud_setting, a.k.a. ubbr (USART Baud Rate Register)
+  R_UBRRH = baud_setting >> 8;
+  R_UBRRL = baud_setting;
+
+  B_RXEN = 1;
+  B_TXEN = 1;
+  B_RXCIE = 1;
+  if (Cfg::TX_SIZE > 0) B_UDRIE = 0;
+  _written = false;
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::end() {
+  B_RXEN = 0;
+  B_TXEN = 0;
+  B_RXCIE = 0;
+  B_UDRIE = 0;
+}
+
+template<typename Cfg>
+int MarlinSerial<Cfg>::peek() {
+  const ring_buffer_pos_t h = atomic_read_rx_head(), t = rx_buffer.tail;
+  return h == t ? -1 : rx_buffer.buffer[t];
+}
+
+template<typename Cfg>
+int MarlinSerial<Cfg>::read() {
+  const ring_buffer_pos_t h = atomic_read_rx_head();
+
+  // Read the tail. Main thread owns it, so it is safe to directly read it
+  ring_buffer_pos_t t = rx_buffer.tail;
+
+  // If nothing to read, return now
+  if (h == t) return -1;
+
+  // Get the next char
+  const int v = rx_buffer.buffer[t];
+  t = (ring_buffer_pos_t)(t + 1) & (Cfg::RX_SIZE - 1);
+
+  // Advance tail - Making sure the RX ISR will always get an stable value, even
+  // if it interrupts the writing of the value of that variable in the middle.
+  atomic_set_rx_tail(t);
+
+  if (Cfg::XONOFF) {
+    // If the XOFF char was sent, or about to be sent...
+    if ((xon_xoff_state & XON_XOFF_CHAR_MASK) == XOFF_CHAR) {
+      // Get count of bytes in the RX buffer
+      const ring_buffer_pos_t rx_count = (ring_buffer_pos_t)(h - t) & (ring_buffer_pos_t)(Cfg::RX_SIZE - 1);
+      if (rx_count < (Cfg::RX_SIZE) / 10) {
         if (Cfg::TX_SIZE > 0) {
           // Signal we want an XON character to be sent.
           xon_xoff_state = XON_CHAR;
-          // Enable TX ISR. Non atomic, but it will eventually enable it.
+          // Enable TX ISR. Non atomic, but it will eventually enable them
           B_UDRIE = 1;
         }
         else {
@@ -453,299 +416,334 @@
     }
   }
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::write(const uint8_t c) {
-    if (Cfg::TX_SIZE == 0) {
-
-      _written = true;
-      while (!B_UDRE) sw_barrier();
-      R_UDR = c;
-
-    }
-    else {
-
-      _written = true;
-
-      // If the TX interrupts are disabled and the data register
-      // is empty, just write the byte to the data register and
-      // be done. This shortcut helps significantly improve the
-      // effective datarate at high (>500kbit/s) bitrates, where
-      // interrupt overhead becomes a slowdown.
-      // Yes, there is a race condition between the sending of the
-      // XOFF char at the RX ISR, but it is properly handled there
-      if (!B_UDRIE && B_UDRE) {
-        R_UDR = c;
-
-        // clear the TXC bit -- "can be cleared by writing a one to its bit
-        // location". This makes sure flush() won't return until the bytes
-        // actually got written
-        B_TXC = 1;
-        return;
-      }
-
-      const uint8_t i = (tx_buffer.head + 1) & (Cfg::TX_SIZE - 1);
-
-      // If global interrupts are disabled (as the result of being called from an ISR)...
-      if (!ISRS_ENABLED()) {
-
-        // Make room by polling if it is possible to transmit, and do so!
-        while (i == tx_buffer.tail) {
-
-          // If we can transmit another byte, do it.
-          if (B_UDRE) _tx_udr_empty_irq();
-
-          // Make sure compiler rereads tx_buffer.tail
-          sw_barrier();
-        }
+  return v;
+}
+
+template<typename Cfg>
+typename MarlinSerial<Cfg>::ring_buffer_pos_t MarlinSerial<Cfg>::available() {
+  const ring_buffer_pos_t h = atomic_read_rx_head(), t = rx_buffer.tail;
+  return (ring_buffer_pos_t)(Cfg::RX_SIZE + h - t) & (Cfg::RX_SIZE - 1);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::flush() {
+
+  // Set the tail to the head:
+  //  - Read the RX head index in a safe way. (See atomic_read_rx_head.)
+  //  - Set the tail, making sure the RX ISR will always get a stable value, even
+  //    if it interrupts the writing of the value of that variable in the middle.
+  atomic_set_rx_tail(atomic_read_rx_head());
+
+  if (Cfg::XONOFF) {
+    // If the XOFF char was sent, or about to be sent...
+    if ((xon_xoff_state & XON_XOFF_CHAR_MASK) == XOFF_CHAR) {
+      if (Cfg::TX_SIZE > 0) {
+        // Signal we want an XON character to be sent.
+        xon_xoff_state = XON_CHAR;
+        // Enable TX ISR. Non atomic, but it will eventually enable it.
+        B_UDRIE = 1;
       }
       else {
-        // Interrupts are enabled, just wait until there is space
-        while (i == tx_buffer.tail) sw_barrier();
+        // If not using TX interrupts, we must send the XON char now
+        xon_xoff_state = XON_CHAR | XON_XOFF_CHAR_SENT;
+        while (!B_UDRE) sw_barrier();
+        R_UDR = XON_CHAR;
       }
-
-      // Store new char. head is always safe to move
-      tx_buffer.buffer[tx_buffer.head] = c;
-      tx_buffer.head = i;
-
-      // Enable TX ISR - Non atomic, but it will eventually enable TX ISR
-      B_UDRIE = 1;
     }
   }
+}
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::flushTX() {
+template<typename Cfg>
+void MarlinSerial<Cfg>::write(const uint8_t c) {
+  if (Cfg::TX_SIZE == 0) {
 
-    if (Cfg::TX_SIZE == 0) {
-      // No bytes written, no need to flush. This special case is needed since there's
-      // no way to force the TXC (transmit complete) bit to 1 during initialization.
-      if (!_written) return;
+    _written = true;
+    while (!B_UDRE) sw_barrier();
+    R_UDR = c;
 
-      // Wait until everything was transmitted
-      while (!B_TXC) sw_barrier();
+  }
+  else {
 
-      // At this point nothing is queued anymore (DRIE is disabled) and
-      // the hardware finished transmission (TXC is set).
+    _written = true;
 
-    }
-    else {
+    // If the TX interrupts are disabled and the data register
+    // is empty, just write the byte to the data register and
+    // be done. This shortcut helps significantly improve the
+    // effective datarate at high (>500kbit/s) bitrates, where
+    // interrupt overhead becomes a slowdown.
+    // Yes, there is a race condition between the sending of the
+    // XOFF char at the RX ISR, but it is properly handled there
+    if (!B_UDRIE && B_UDRE) {
+      R_UDR = c;
 
-      // No bytes written, no need to flush. This special case is needed since there's
-      // no way to force the TXC (transmit complete) bit to 1 during initialization.
-      if (!_written) return;
+      // clear the TXC bit -- "can be cleared by writing a one to its bit
+      // location". This makes sure flush() won't return until the bytes
+      // actually got written
+      B_TXC = 1;
+      return;
+    }
 
-      // If global interrupts are disabled (as the result of being called from an ISR)...
-      if (!ISRS_ENABLED()) {
+    const uint8_t i = (tx_buffer.head + 1) & (Cfg::TX_SIZE - 1);
 
-        // Wait until everything was transmitted - We must do polling, as interrupts are disabled
-        while (tx_buffer.head != tx_buffer.tail || !B_TXC) {
+    // If global interrupts are disabled (as the result of being called from an ISR)...
+    if (!ISRS_ENABLED()) {
 
-          // If there is more space, send an extra character
-          if (B_UDRE) _tx_udr_empty_irq();
+      // Make room by polling if it is possible to transmit, and do so!
+      while (i == tx_buffer.tail) {
 
-          sw_barrier();
-        }
+        // If we can transmit another byte, do it.
+        if (B_UDRE) _tx_udr_empty_irq();
 
+        // Make sure compiler rereads tx_buffer.tail
+        sw_barrier();
       }
-      else {
-        // Wait until everything was transmitted
-        while (tx_buffer.head != tx_buffer.tail || !B_TXC) sw_barrier();
-      }
-
-      // At this point nothing is queued anymore (DRIE is disabled) and
-      // the hardware finished transmission (TXC is set).
     }
-  }
+    else {
+      // Interrupts are enabled, just wait until there is space
+      while (i == tx_buffer.tail) sw_barrier();
+    }
 
-  /**
-   * Imports from print.h
-   */
+    // Store new char. head is always safe to move
+    tx_buffer.buffer[tx_buffer.head] = c;
+    tx_buffer.head = i;
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::print(char c, int base) {
-    print((long)c, base);
+    // Enable TX ISR - Non atomic, but it will eventually enable TX ISR
+    B_UDRIE = 1;
   }
+}
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::print(unsigned char b, int base) {
-    print((unsigned long)b, base);
-  }
+template<typename Cfg>
+void MarlinSerial<Cfg>::flushTX() {
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::print(int n, int base) {
-    print((long)n, base);
-  }
+  if (Cfg::TX_SIZE == 0) {
+    // No bytes written, no need to flush. This special case is needed since there's
+    // no way to force the TXC (transmit complete) bit to 1 during initialization.
+    if (!_written) return;
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::print(unsigned int n, int base) {
-    print((unsigned long)n, base);
-  }
+    // Wait until everything was transmitted
+    while (!B_TXC) sw_barrier();
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::print(long n, int base) {
-    if (base == 0) write(n);
-    else if (base == 10) {
-      if (n < 0) { print('-'); n = -n; }
-      printNumber(n, 10);
-    }
-    else
-      printNumber(n, base);
-  }
+    // At this point nothing is queued anymore (DRIE is disabled) and
+    // the hardware finished transmission (TXC is set).
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::print(unsigned long n, int base) {
-    if (base == 0) write(n);
-    else printNumber(n, base);
   }
+  else {
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::print(double n, int digits) {
-    printFloat(n, digits);
-  }
+    // No bytes written, no need to flush. This special case is needed since there's
+    // no way to force the TXC (transmit complete) bit to 1 during initialization.
+    if (!_written) return;
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println() {
-    print('\r');
-    print('\n');
-  }
+    // If global interrupts are disabled (as the result of being called from an ISR)...
+    if (!ISRS_ENABLED()) {
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(const String& s) {
-    print(s);
-    println();
-  }
+      // Wait until everything was transmitted - We must do polling, as interrupts are disabled
+      while (tx_buffer.head != tx_buffer.tail || !B_TXC) {
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(const char c[]) {
-    print(c);
-    println();
-  }
+        // If there is more space, send an extra character
+        if (B_UDRE) _tx_udr_empty_irq();
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(char c, int base) {
-    print(c, base);
-    println();
-  }
-
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(unsigned char b, int base) {
-    print(b, base);
-    println();
-  }
+        sw_barrier();
+      }
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(int n, int base) {
-    print(n, base);
-    println();
-  }
+    }
+    else {
+      // Wait until everything was transmitted
+      while (tx_buffer.head != tx_buffer.tail || !B_TXC) sw_barrier();
+    }
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(unsigned int n, int base) {
-    print(n, base);
-    println();
+    // At this point nothing is queued anymore (DRIE is disabled) and
+    // the hardware finished transmission (TXC is set).
   }
+}
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(long n, int base) {
-    print(n, base);
-    println();
-  }
+/**
+ * Imports from print.h
+ */
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(unsigned long n, int base) {
-    print(n, base);
-    println();
+template<typename Cfg>
+void MarlinSerial<Cfg>::print(char c, int base) {
+  print((long)c, base);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::print(unsigned char b, int base) {
+  print((unsigned long)b, base);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::print(int n, int base) {
+  print((long)n, base);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::print(unsigned int n, int base) {
+  print((unsigned long)n, base);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::print(long n, int base) {
+  if (base == 0) write(n);
+  else if (base == 10) {
+    if (n < 0) { print('-'); n = -n; }
+    printNumber(n, 10);
+  }
+  else
+    printNumber(n, base);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::print(unsigned long n, int base) {
+  if (base == 0) write(n);
+  else printNumber(n, base);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::print(double n, int digits) {
+  printFloat(n, digits);
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println() {
+  print('\r');
+  print('\n');
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(const String& s) {
+  print(s);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(const char c[]) {
+  print(c);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(char c, int base) {
+  print(c, base);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(unsigned char b, int base) {
+  print(b, base);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(int n, int base) {
+  print(n, base);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(unsigned int n, int base) {
+  print(n, base);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(long n, int base) {
+  print(n, base);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(unsigned long n, int base) {
+  print(n, base);
+  println();
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::println(double n, int digits) {
+  print(n, digits);
+  println();
+}
+
+// Private Methods
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::printNumber(unsigned long n, uint8_t base) {
+  if (n) {
+    unsigned char buf[8 * sizeof(long)]; // Enough space for base 2
+    int8_t i = 0;
+    while (n) {
+      buf[i++] = n % base;
+      n /= base;
+    }
+    while (i--)
+      print((char)(buf[i] + (buf[i] < 10 ? '0' : 'A' - 10)));
+  }
+  else
+    print('0');
+}
+
+template<typename Cfg>
+void MarlinSerial<Cfg>::printFloat(double number, uint8_t digits) {
+  // Handle negative numbers
+  if (number < 0.0) {
+    print('-');
+    number = -number;
+  }
+
+  // Round correctly so that print(1.999, 2) prints as "2.00"
+  double rounding = 0.5;
+  LOOP_L_N(i, digits) rounding *= 0.1;
+  number += rounding;
+
+  // Extract the integer part of the number and print it
+  unsigned long int_part = (unsigned long)number;
+  double remainder = number - (double)int_part;
+  print(int_part);
+
+  // Print the decimal point, but only if there are digits beyond
+  if (digits) {
+    print('.');
+    // Extract digits from the remainder one at a time
+    while (digits--) {
+      remainder *= 10.0;
+      int toPrint = int(remainder);
+      print(toPrint);
+      remainder -= toPrint;
+    }
   }
+}
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::println(double n, int digits) {
-    print(n, digits);
-    println();
-  }
+// Hookup ISR handlers
+ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _RX_vect)) {
+  MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::store_rxd_char();
+}
 
-  // Private Methods
+ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _UDRE_vect)) {
+  MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::_tx_udr_empty_irq();
+}
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::printNumber(unsigned long n, uint8_t base) {
-    if (n) {
-      unsigned char buf[8 * sizeof(long)]; // Enough space for base 2
-      int8_t i = 0;
-      while (n) {
-        buf[i++] = n % base;
-        n /= base;
-      }
-      while (i--)
-        print((char)(buf[i] + (buf[i] < 10 ? '0' : 'A' - 10)));
-    }
-    else
-      print('0');
-  }
+// Preinstantiate
+template class MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>;
 
-  template<typename Cfg>
-  void MarlinSerial<Cfg>::printFloat(double number, uint8_t digits) {
-    // Handle negative numbers
-    if (number < 0.0) {
-      print('-');
-      number = -number;
-    }
+// Instantiate
+MarlinSerial<MarlinSerialCfg<SERIAL_PORT>> customizedSerial1;
 
-    // Round correctly so that print(1.999, 2) prints as "2.00"
-    double rounding = 0.5;
-    LOOP_L_N(i, digits) rounding *= 0.1;
-    number += rounding;
-
-    // Extract the integer part of the number and print it
-    unsigned long int_part = (unsigned long)number;
-    double remainder = number - (double)int_part;
-    print(int_part);
-
-    // Print the decimal point, but only if there are digits beyond
-    if (digits) {
-      print('.');
-      // Extract digits from the remainder one at a time
-      while (digits--) {
-        remainder *= 10.0;
-        int toPrint = int(remainder);
-        print(toPrint);
-        remainder -= toPrint;
-      }
-    }
-  }
+#ifdef SERIAL_PORT_2
 
   // Hookup ISR handlers
-  ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _RX_vect)) {
-    MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::store_rxd_char();
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _RX_vect)) {
+    MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::store_rxd_char();
   }
 
-  ISR(SERIAL_REGNAME(USART, SERIAL_PORT, _UDRE_vect)) {
-    MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>::_tx_udr_empty_irq();
+  ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _UDRE_vect)) {
+    MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::_tx_udr_empty_irq();
   }
 
   // Preinstantiate
-  template class MarlinSerial<MarlinSerialCfg<SERIAL_PORT>>;
+  template class MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>;
 
   // Instantiate
-  MarlinSerial<MarlinSerialCfg<SERIAL_PORT>> customizedSerial1;
-
-  #ifdef SERIAL_PORT_2
+  MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>> customizedSerial2;
 
-    // Hookup ISR handlers
-    ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _RX_vect)) {
-      MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::store_rxd_char();
-    }
-
-    ISR(SERIAL_REGNAME(USART, SERIAL_PORT_2, _UDRE_vect)) {
-      MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>::_tx_udr_empty_irq();
-    }
-
-    // Preinstantiate
-    template class MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>>;
-
-    // Instantiate
-    MarlinSerial<MarlinSerialCfg<SERIAL_PORT_2>> customizedSerial2;
-
-  #endif
-
-#endif // !USBCON && (UBRRH || UBRR0H || UBRR1H || UBRR2H || UBRR3H)
+#endif
 
 #ifdef MMU2_SERIAL_PORT
 
@@ -794,6 +792,8 @@
 
 #endif
 
+#endif // !USBCON && (UBRRH || UBRR0H || UBRR1H || UBRR2H || UBRR3H)
+
 // For AT90USB targets use the UART for BT interfacing
 #if defined(USBCON) && ENABLED(BLUETOOTH)
   HardwareSerial bluetoothSerial;

From 1bb005d969cb40ce1d3a4c3653aedb259ddfcd5a Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Wed, 23 Sep 2020 22:06:39 -0500
Subject: [PATCH 25/33] Ok to keep JTAG off?

---
 Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h b/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
index 188a3581e26a..a3cb987fff0b 100644
--- a/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
+++ b/Marlin/src/pins/stm32f1/pins_BTT_SKR_E3_DIP.h
@@ -28,7 +28,7 @@
 #define BOARD_INFO_NAME "BTT SKR E3 DIP V1.0"
 
 // Release PB3/PB4 (TMC_SW Pins) from JTAG pins
-// #define DISABLE_JTAG
+#define DISABLE_JTAG
 
 // Ignore temp readings during development.
 //#define BOGUS_TEMPERATURE_GRACE_PERIOD    2000

From d3d5f917960dcd0ae1b5a5510076670edd6268a2 Mon Sep 17 00:00:00 2001
From: Jason Smith <jason.inet@gmail.com>
Date: Thu, 24 Sep 2020 00:38:07 -0700
Subject: [PATCH 26/33] Remove duplicate LCD_SERIAL check

---
 Marlin/src/HAL/STM32F1/MarlinSerial.cpp | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
index 9418403c7a6d..3402f8b75826 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
@@ -141,9 +141,6 @@ constexpr bool IsSerialClassAllowed(const HardwareSerial&) { return false; }
 #ifdef LCD_SERIAL
   CHECK_CFG_SERIAL(LCD_SERIAL);
 #endif
-#ifdef LCD_SERIAL
-  CHECK_CFG_SERIAL(LCD_SERIAL);
-#endif
 #if AXIS_HAS_HW_SERIAL(X)
   CHECK_AXIS_SERIAL(X);
 #endif

From f49dc6b1c0a7db186d64c979c9e739468883ad42 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Thu, 24 Sep 2020 19:37:36 -0500
Subject: [PATCH 27/33] Add MSerial::emergency_parser_enabled

---
 Marlin/src/HAL/AVR/MarlinSerial.cpp     |  1 +
 Marlin/src/HAL/DUE/MarlinSerial.cpp     |  1 +
 Marlin/src/HAL/LINUX/include/serial.h   |  1 +
 Marlin/src/HAL/LPC1768/MarlinSerial.h   |  1 +
 Marlin/src/HAL/LPC1768/usb_serial.cpp   |  2 ++
 Marlin/src/HAL/STM32/MarlinSerial.h     |  4 ++++
 Marlin/src/HAL/STM32F1/MarlinSerial.cpp | 14 +++++++-------
 Marlin/src/HAL/STM32F1/MarlinSerial.h   | 15 ++++++++-------
 Marlin/src/HAL/STM32F1/msc_sd.h         |  1 +
 buildroot/tests/mks_robin_pro-tests     |  1 +
 10 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/Marlin/src/HAL/AVR/MarlinSerial.cpp b/Marlin/src/HAL/AVR/MarlinSerial.cpp
index 63599efd4132..a4980138774b 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.cpp
+++ b/Marlin/src/HAL/AVR/MarlinSerial.cpp
@@ -134,6 +134,7 @@ template<typename Cfg>
 FORCE_INLINE void MarlinSerial<Cfg>::store_rxd_char() {
 
   static EmergencyParser::State emergency_state; // = EP_RESET
+  static inline bool emergency_parser_enabled() { return Cfg::EMERGENCYPARSER; }
 
   // This must read the R_UCSRA register before reading the received byte to detect error causes
   if (Cfg::DROPPED_RX && B_DOR && !++rx_dropped_bytes) --rx_dropped_bytes;
diff --git a/Marlin/src/HAL/DUE/MarlinSerial.cpp b/Marlin/src/HAL/DUE/MarlinSerial.cpp
index c9a372eeb14f..2d53c623222d 100644
--- a/Marlin/src/HAL/DUE/MarlinSerial.cpp
+++ b/Marlin/src/HAL/DUE/MarlinSerial.cpp
@@ -52,6 +52,7 @@ template<typename Cfg>
 FORCE_INLINE void MarlinSerial<Cfg>::store_rxd_char() {
 
   static EmergencyParser::State emergency_state; // = EP_RESET
+  static inline bool emergency_parser_enabled() { return Cfg::EMERGENCYPARSER; }
 
   // Get the tail - Nothing can alter its value while we are at this ISR
   const ring_buffer_pos_t t = rx_buffer.tail;
diff --git a/Marlin/src/HAL/LINUX/include/serial.h b/Marlin/src/HAL/LINUX/include/serial.h
index 154e95aec262..94e0c758ee12 100644
--- a/Marlin/src/HAL/LINUX/include/serial.h
+++ b/Marlin/src/HAL/LINUX/include/serial.h
@@ -79,6 +79,7 @@ class HalSerial {
 
   #if ENABLED(EMERGENCY_PARSER)
     EmergencyParser::State emergency_state;
+    static inline bool emergency_parser_enabled() { return true; }
   #endif
 
   HalSerial() { host_connected = true; }
diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.h b/Marlin/src/HAL/LPC1768/MarlinSerial.h
index 98ce73d377a6..8d6b64378a0a 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.h
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.h
@@ -57,6 +57,7 @@ class MarlinSerial : public HardwareSerial<RX_BUFFER_SIZE, TX_BUFFER_SIZE> {
     }
 
     EmergencyParser::State emergency_state;
+    static inline bool emergency_parser_enabled() { return true; }
   #endif
 };
 
diff --git a/Marlin/src/HAL/LPC1768/usb_serial.cpp b/Marlin/src/HAL/LPC1768/usb_serial.cpp
index 63a570efdfa8..d225ce418860 100644
--- a/Marlin/src/HAL/LPC1768/usb_serial.cpp
+++ b/Marlin/src/HAL/LPC1768/usb_serial.cpp
@@ -26,7 +26,9 @@
 #if ENABLED(EMERGENCY_PARSER)
 
 #include "../../feature/e_parser.h"
+
 EmergencyParser::State emergency_state;
+
 bool CDC_RecvCallback(const char buffer) {
   emergency_parser.update(emergency_state, buffer);
   return true;
diff --git a/Marlin/src/HAL/STM32/MarlinSerial.h b/Marlin/src/HAL/STM32/MarlinSerial.h
index 5ab97ff3a993..3611cc78d7ce 100644
--- a/Marlin/src/HAL/STM32/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32/MarlinSerial.h
@@ -35,6 +35,10 @@ class MarlinSerial : public HardwareSerial {
       #endif
   { }
 
+  #if ENABLED(EMERGENCY_PARSER)
+    static inline bool emergency_parser_enabled() { return true; }
+  #endif
+
   void begin(unsigned long baud, uint8_t config);
   inline void begin(unsigned long baud) { begin(baud, SERIAL_8N1); }
 
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
index 3402f8b75826..ebf11cb429fa 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
@@ -53,7 +53,7 @@ static inline __always_inline void my_usart_irq(ring_buffer *rb, ring_buffer *wb
         rb_push_insert(rb, c);
       #endif
       #if ENABLED(EMERGENCY_PARSER)
-        if (serial.emergency_parser_enabled)
+        if (serial.emergency_parser_enabled())
           emergency_parser.update(serial.emergency_state, c);
       #endif
     }
@@ -90,12 +90,12 @@ constexpr bool serial_handles_emergency(int port) {
   ;
 }
 
-#define DEFINE_HWSERIAL_MARLIN(name, n)  \
-  MarlinSerial name(USART##n,            \
-            BOARD_USART##n##_TX_PIN,     \
-            BOARD_USART##n##_RX_PIN,     \
-            serial_handles_emergency(n));\
-  extern "C" void __irq_usart##n(void) { \
+#define DEFINE_HWSERIAL_MARLIN(name, n)   \
+  MarlinSerial name(USART##n,             \
+            BOARD_USART##n##_TX_PIN,      \
+            BOARD_USART##n##_RX_PIN,      \
+            serial_handles_emergency(n)); \
+  extern "C" void __irq_usart##n(void) {  \
     my_usart_irq(USART##n->rb, USART##n->wb, USART##n##_BASE, MSerial##n); \
   }
 
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index 5c226882f702..f347dd43a046 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -35,10 +35,16 @@
 
 class MarlinSerial : public HardwareSerial {
 public:
-  MarlinSerial(struct usart_dev *usart_device, uint8 tx_pin, uint8 rx_pin, bool TERN_(EMERGENCY_PARSER, emergency_parser)) :
+  #if ENABLED(EMERGENCY_PARSER)
+    const bool ep_enabled;
+    EmergencyParser::State emergency_state;
+    inline bool emergency_parser_enabled() { return ep_enabled; }
+  #endif
+
+  MarlinSerial(struct usart_dev *usart_device, uint8 tx_pin, uint8 rx_pin, bool TERN_(EMERGENCY_PARSER, ep_capable)) :
     HardwareSerial(usart_device, tx_pin, rx_pin)
     #if ENABLED(EMERGENCY_PARSER)
-      , emergency_parser_enabled(emergency_parser)
+      , ep_enabled(ep_capable)
       , emergency_state(EmergencyParser::State::EP_RESET)
     #endif
     { }
@@ -54,11 +60,6 @@ class MarlinSerial : public HardwareSerial {
       nvic_irq_set_priority(c_dev()->irq_num, UART_IRQ_PRIO);
     }
   #endif
-
-  #if ENABLED(EMERGENCY_PARSER)
-    bool emergency_parser_enabled;
-    EmergencyParser::State emergency_state;
-  #endif
 };
 
 extern MarlinSerial MSerial1;
diff --git a/Marlin/src/HAL/STM32F1/msc_sd.h b/Marlin/src/HAL/STM32F1/msc_sd.h
index d9cdbe6bb3d1..1e4e4c44b1b5 100644
--- a/Marlin/src/HAL/STM32F1/msc_sd.h
+++ b/Marlin/src/HAL/STM32F1/msc_sd.h
@@ -32,6 +32,7 @@ class MarlinUSBCompositeSerial : public USBCompositeSerial {
 
   #if ENABLED(EMERGENCY_PARSER)
     EmergencyParser::State emergency_state;
+    inline bool emergency_parser_enabled() { return true; }
   #endif
 };
 
diff --git a/buildroot/tests/mks_robin_pro-tests b/buildroot/tests/mks_robin_pro-tests
index cfd36832fdef..7ae4670fedac 100644
--- a/buildroot/tests/mks_robin_pro-tests
+++ b/buildroot/tests/mks_robin_pro-tests
@@ -7,6 +7,7 @@
 set -e
 
 use_example_configs Mks/Robin_Pro
+opt_enable EMERGENCY_PARSER
 opt_set SDCARD_CONNECTION LCD
 opt_set X_DRIVER_TYPE TMC2209
 opt_set Y_DRIVER_TYPE TMC2130

From 9428396943db923df55bd13d306b4080b45bf4c2 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Thu, 24 Sep 2020 19:44:38 -0500
Subject: [PATCH 28/33] Add a bunch of logic

---
 Marlin/src/HAL/STM32F1/MarlinSerial.cpp | 24 ++++++++++++++++--------
 Marlin/src/HAL/STM32F1/MarlinSerial.h   | 13 +++++++------
 2 files changed, 23 insertions(+), 14 deletions(-)

diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
index ebf11cb429fa..eaf29440c614 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
@@ -108,15 +108,23 @@ constexpr bool serial_handles_emergency(int port) {
     my_usart_irq(UART##n->rb, UART##n->wb, UART##n##_BASE, MSerial##n); \
   }
 
-// Instantiate all UARTs even if they are not needed
-// This avoids a bunch of logic to figure out every serial
-// port which may be in use on the system.
-DEFINE_HWSERIAL_MARLIN(MSerial1, 1);
-DEFINE_HWSERIAL_MARLIN(MSerial2, 2);
-DEFINE_HWSERIAL_MARLIN(MSerial3, 3);
+// Instantiate the required UARTs
+#if USING_SERIAL_1
+  DEFINE_HWSERIAL_MARLIN(MSerial1, 1);
+#endif
+#if USING_SERIAL_2
+  DEFINE_HWSERIAL_MARLIN(MSerial2, 2);
+#endif
+#if USING_SERIAL_3
+  DEFINE_HWSERIAL_MARLIN(MSerial3, 3);
+#endif
 #if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
-  DEFINE_HWSERIAL_UART_MARLIN(MSerial4, 4);
-  DEFINE_HWSERIAL_UART_MARLIN(MSerial5, 5);
+  #if USING_SERIAL_4
+    DEFINE_HWSERIAL_UART_MARLIN(MSerial4, 4);
+  #endif
+  #if USING_SERIAL_5
+    DEFINE_HWSERIAL_UART_MARLIN(MSerial5, 5);
+  #endif
 #endif
 
 // Check the type of each serial port by passing it to a template function.
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index f347dd43a046..504593fb6bab 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -50,7 +50,7 @@ class MarlinSerial : public HardwareSerial {
     { }
 
   #ifdef UART_IRQ_PRIO
-    // shadow the parent methods to set irq priority after the begin
+    // Shadow the parent methods to set IRQ priority after begin()
     void begin(uint32 baud) {
       MarlinSerial::begin(baud, SERIAL_8N1);
     }
@@ -62,10 +62,11 @@ class MarlinSerial : public HardwareSerial {
   #endif
 };
 
-extern MarlinSerial MSerial1;
-extern MarlinSerial MSerial2;
-extern MarlinSerial MSerial3;
+// Declare the required UARTs
+TERN_(USING_SERIAL_1, extern MarlinSerial MSerial1);
+TERN_(USING_SERIAL_2, extern MarlinSerial MSerial2);
+TERN_(USING_SERIAL_3, extern MarlinSerial MSerial3);
 #if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
-  extern MarlinSerial MSerial4;
-  extern MarlinSerial MSerial5;
+  TERN_(USING_SERIAL_4, extern MarlinSerial MSerial4);
+  TERN_(USING_SERIAL_5, extern MarlinSerial MSerial5);
 #endif

From d98d7d86daece80799bc815d74354bdfb2c037f6 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Thu, 24 Sep 2020 19:50:46 -0500
Subject: [PATCH 29/33] Apply to other HALs

---
 Marlin/src/HAL/LPC1768/MarlinSerial.h |  9 +++++----
 Marlin/src/HAL/STM32/MarlinSerial.h   | 23 ++++++++++++-----------
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.h b/Marlin/src/HAL/LPC1768/MarlinSerial.h
index 8d6b64378a0a..fc99ce35417e 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.h
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.h
@@ -61,7 +61,8 @@ class MarlinSerial : public HardwareSerial<RX_BUFFER_SIZE, TX_BUFFER_SIZE> {
   #endif
 };
 
-extern MarlinSerial MSerial;
-extern MarlinSerial MSerial1;
-extern MarlinSerial MSerial2;
-extern MarlinSerial MSerial3;
+// Declare the required UARTs
+TERN_(USING_SERIAL_0, extern MarlinSerial MSerial);
+TERN_(USING_SERIAL_1, extern MarlinSerial MSerial1);
+TERN_(USING_SERIAL_2, extern MarlinSerial MSerial2);
+TERN_(USING_SERIAL_3, extern MarlinSerial MSerial3);
diff --git a/Marlin/src/HAL/STM32/MarlinSerial.h b/Marlin/src/HAL/STM32/MarlinSerial.h
index 3611cc78d7ce..e28bb530db0f 100644
--- a/Marlin/src/HAL/STM32/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32/MarlinSerial.h
@@ -51,14 +51,15 @@ class MarlinSerial : public HardwareSerial {
   #endif
 };
 
-extern MarlinSerial MSerial1;
-extern MarlinSerial MSerial2;
-extern MarlinSerial MSerial3;
-extern MarlinSerial MSerial4;
-extern MarlinSerial MSerial5;
-extern MarlinSerial MSerial6;
-extern MarlinSerial MSerial7;
-extern MarlinSerial MSerial8;
-extern MarlinSerial MSerial9;
-extern MarlinSerial MSerial10;
-extern MarlinSerial MSerialLP1;
+// Declare the required UARTs
+TERN_(USING_SERIAL_1, extern MarlinSerial MSerial1);
+TERN_(USING_SERIAL_2, extern MarlinSerial MSerial2);
+TERN_(USING_SERIAL_3, extern MarlinSerial MSerial3);
+TERN_(USING_SERIAL_4, extern MarlinSerial MSerial4);
+TERN_(USING_SERIAL_5, extern MarlinSerial MSerial5);
+TERN_(USING_SERIAL_6, extern MarlinSerial MSerial6);
+TERN_(USING_SERIAL_7, extern MarlinSerial MSerial7);
+TERN_(USING_SERIAL_8, extern MarlinSerial MSerial8);
+TERN_(USING_SERIAL_9, extern MarlinSerial MSerial9);
+TERN_(USING_SERIAL_10, extern MarlinSerial MSerial10);
+TERN_(USING_SERIAL_LP1, extern MarlinSerial MSerialLP1); // LPUART

From f8d538dd12da6c0e0d1ef2f5fc6472da4490a9bf Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Thu, 24 Sep 2020 20:02:26 -0500
Subject: [PATCH 30/33] Fix ep-enabled

---
 Marlin/src/HAL/AVR/MarlinSerial.cpp | 1 -
 Marlin/src/HAL/AVR/MarlinSerial.h   | 2 ++
 Marlin/src/HAL/DUE/MarlinSerial.cpp | 1 -
 Marlin/src/HAL/DUE/MarlinSerial.h   | 2 ++
 4 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/HAL/AVR/MarlinSerial.cpp b/Marlin/src/HAL/AVR/MarlinSerial.cpp
index a4980138774b..63599efd4132 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.cpp
+++ b/Marlin/src/HAL/AVR/MarlinSerial.cpp
@@ -134,7 +134,6 @@ template<typename Cfg>
 FORCE_INLINE void MarlinSerial<Cfg>::store_rxd_char() {
 
   static EmergencyParser::State emergency_state; // = EP_RESET
-  static inline bool emergency_parser_enabled() { return Cfg::EMERGENCYPARSER; }
 
   // This must read the R_UCSRA register before reading the received byte to detect error causes
   if (Cfg::DROPPED_RX && B_DOR && !++rx_dropped_bytes) --rx_dropped_bytes;
diff --git a/Marlin/src/HAL/AVR/MarlinSerial.h b/Marlin/src/HAL/AVR/MarlinSerial.h
index 6197308bb014..cb906e2b6572 100644
--- a/Marlin/src/HAL/AVR/MarlinSerial.h
+++ b/Marlin/src/HAL/AVR/MarlinSerial.h
@@ -221,6 +221,8 @@
         static ring_buffer_pos_t get_tx_buffer_free();
       #endif
 
+      static inline bool emergency_parser_enabled() { return Cfg::EMERGENCYPARSER; }
+
       FORCE_INLINE static uint8_t dropped() { return Cfg::DROPPED_RX ? rx_dropped_bytes : 0; }
       FORCE_INLINE static uint8_t buffer_overruns() { return Cfg::RX_OVERRUNS ? rx_buffer_overruns : 0; }
       FORCE_INLINE static uint8_t framing_errors() { return Cfg::RX_FRAMING_ERRORS ? rx_framing_errors : 0; }
diff --git a/Marlin/src/HAL/DUE/MarlinSerial.cpp b/Marlin/src/HAL/DUE/MarlinSerial.cpp
index 2d53c623222d..c9a372eeb14f 100644
--- a/Marlin/src/HAL/DUE/MarlinSerial.cpp
+++ b/Marlin/src/HAL/DUE/MarlinSerial.cpp
@@ -52,7 +52,6 @@ template<typename Cfg>
 FORCE_INLINE void MarlinSerial<Cfg>::store_rxd_char() {
 
   static EmergencyParser::State emergency_state; // = EP_RESET
-  static inline bool emergency_parser_enabled() { return Cfg::EMERGENCYPARSER; }
 
   // Get the tail - Nothing can alter its value while we are at this ISR
   const ring_buffer_pos_t t = rx_buffer.tail;
diff --git a/Marlin/src/HAL/DUE/MarlinSerial.h b/Marlin/src/HAL/DUE/MarlinSerial.h
index dfafa1514159..a194eba2f386 100644
--- a/Marlin/src/HAL/DUE/MarlinSerial.h
+++ b/Marlin/src/HAL/DUE/MarlinSerial.h
@@ -122,6 +122,8 @@ class MarlinSerial {
   static void write(const uint8_t c);
   static void flushTX();
 
+  static inline bool emergency_parser_enabled() { return Cfg::EMERGENCYPARSER; }
+
   FORCE_INLINE static uint8_t dropped() { return Cfg::DROPPED_RX ? rx_dropped_bytes : 0; }
   FORCE_INLINE static uint8_t buffer_overruns() { return Cfg::RX_OVERRUNS ? rx_buffer_overruns : 0; }
   FORCE_INLINE static uint8_t framing_errors() { return Cfg::RX_FRAMING_ERRORS ? rx_framing_errors : 0; }

From 9bfdbee8268365e28cbf23640059aa4ab261ce02 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Thu, 24 Sep 2020 20:12:56 -0500
Subject: [PATCH 31/33] Evaluate macro arg

---
 Marlin/src/inc/Conditionals_adv.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Marlin/src/inc/Conditionals_adv.h b/Marlin/src/inc/Conditionals_adv.h
index d3f608e0a476..d8bb1f986b19 100644
--- a/Marlin/src/inc/Conditionals_adv.h
+++ b/Marlin/src/inc/Conditionals_adv.h
@@ -424,7 +424,8 @@
 #endif
 
 // Flag the indexed serial ports that are in use
-#define ANY_SERIAL_IS(N) (defined(SERIAL_PORT) && SERIAL_PORT == (N)) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == (N)) || (defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT == (N))
+#define _ANY_SERIAL_IS(N) (defined(SERIAL_PORT) && SERIAL_PORT == (N)) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == (N)) || (defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT == (N))
+#define  ANY_SERIAL_IS(N) _ANY_SERIAL_IS(N)
 #if ANY_SERIAL_IS(-1)
   #define USING_SERIAL_DEFAULT
 #endif
@@ -455,4 +456,5 @@
 #if ANY_SERIAL_IS(8)
   #define USING_SERIAL_8 1
 #endif
-#undef ANY_SERIAL_IS
+#undef _ANY_SERIAL_IS
+#undef  ANY_SERIAL_IS

From a830dbd4112e2e6f010b10777b981942c40712b2 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Thu, 24 Sep 2020 20:22:03 -0500
Subject: [PATCH 32/33] undo 1

---
 Marlin/src/inc/Conditionals_adv.h | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/Marlin/src/inc/Conditionals_adv.h b/Marlin/src/inc/Conditionals_adv.h
index d8bb1f986b19..d3f608e0a476 100644
--- a/Marlin/src/inc/Conditionals_adv.h
+++ b/Marlin/src/inc/Conditionals_adv.h
@@ -424,8 +424,7 @@
 #endif
 
 // Flag the indexed serial ports that are in use
-#define _ANY_SERIAL_IS(N) (defined(SERIAL_PORT) && SERIAL_PORT == (N)) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == (N)) || (defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT == (N))
-#define  ANY_SERIAL_IS(N) _ANY_SERIAL_IS(N)
+#define ANY_SERIAL_IS(N) (defined(SERIAL_PORT) && SERIAL_PORT == (N)) || (defined(SERIAL_PORT_2) && SERIAL_PORT_2 == (N)) || (defined(LCD_SERIAL_PORT) && LCD_SERIAL_PORT == (N))
 #if ANY_SERIAL_IS(-1)
   #define USING_SERIAL_DEFAULT
 #endif
@@ -456,5 +455,4 @@
 #if ANY_SERIAL_IS(8)
   #define USING_SERIAL_8 1
 #endif
-#undef _ANY_SERIAL_IS
-#undef  ANY_SERIAL_IS
+#undef ANY_SERIAL_IS

From 4c54163fe81a986d0ade68fcd14c159b8ef37553 Mon Sep 17 00:00:00 2001
From: Scott Lahteine <thinkyhead@users.noreply.github.com>
Date: Thu, 24 Sep 2020 20:22:39 -0500
Subject: [PATCH 33/33] Revert serial logic

---
 Marlin/src/HAL/LPC1768/MarlinSerial.h   |  9 ++++-----
 Marlin/src/HAL/STM32/MarlinSerial.h     | 23 +++++++++++------------
 Marlin/src/HAL/STM32F1/MarlinSerial.cpp | 24 ++++++++----------------
 Marlin/src/HAL/STM32F1/MarlinSerial.h   | 11 +++++------
 4 files changed, 28 insertions(+), 39 deletions(-)

diff --git a/Marlin/src/HAL/LPC1768/MarlinSerial.h b/Marlin/src/HAL/LPC1768/MarlinSerial.h
index fc99ce35417e..8d6b64378a0a 100644
--- a/Marlin/src/HAL/LPC1768/MarlinSerial.h
+++ b/Marlin/src/HAL/LPC1768/MarlinSerial.h
@@ -61,8 +61,7 @@ class MarlinSerial : public HardwareSerial<RX_BUFFER_SIZE, TX_BUFFER_SIZE> {
   #endif
 };
 
-// Declare the required UARTs
-TERN_(USING_SERIAL_0, extern MarlinSerial MSerial);
-TERN_(USING_SERIAL_1, extern MarlinSerial MSerial1);
-TERN_(USING_SERIAL_2, extern MarlinSerial MSerial2);
-TERN_(USING_SERIAL_3, extern MarlinSerial MSerial3);
+extern MarlinSerial MSerial;
+extern MarlinSerial MSerial1;
+extern MarlinSerial MSerial2;
+extern MarlinSerial MSerial3;
diff --git a/Marlin/src/HAL/STM32/MarlinSerial.h b/Marlin/src/HAL/STM32/MarlinSerial.h
index e28bb530db0f..3611cc78d7ce 100644
--- a/Marlin/src/HAL/STM32/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32/MarlinSerial.h
@@ -51,15 +51,14 @@ class MarlinSerial : public HardwareSerial {
   #endif
 };
 
-// Declare the required UARTs
-TERN_(USING_SERIAL_1, extern MarlinSerial MSerial1);
-TERN_(USING_SERIAL_2, extern MarlinSerial MSerial2);
-TERN_(USING_SERIAL_3, extern MarlinSerial MSerial3);
-TERN_(USING_SERIAL_4, extern MarlinSerial MSerial4);
-TERN_(USING_SERIAL_5, extern MarlinSerial MSerial5);
-TERN_(USING_SERIAL_6, extern MarlinSerial MSerial6);
-TERN_(USING_SERIAL_7, extern MarlinSerial MSerial7);
-TERN_(USING_SERIAL_8, extern MarlinSerial MSerial8);
-TERN_(USING_SERIAL_9, extern MarlinSerial MSerial9);
-TERN_(USING_SERIAL_10, extern MarlinSerial MSerial10);
-TERN_(USING_SERIAL_LP1, extern MarlinSerial MSerialLP1); // LPUART
+extern MarlinSerial MSerial1;
+extern MarlinSerial MSerial2;
+extern MarlinSerial MSerial3;
+extern MarlinSerial MSerial4;
+extern MarlinSerial MSerial5;
+extern MarlinSerial MSerial6;
+extern MarlinSerial MSerial7;
+extern MarlinSerial MSerial8;
+extern MarlinSerial MSerial9;
+extern MarlinSerial MSerial10;
+extern MarlinSerial MSerialLP1;
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
index eaf29440c614..ebf11cb429fa 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.cpp
@@ -108,23 +108,15 @@ constexpr bool serial_handles_emergency(int port) {
     my_usart_irq(UART##n->rb, UART##n->wb, UART##n##_BASE, MSerial##n); \
   }
 
-// Instantiate the required UARTs
-#if USING_SERIAL_1
-  DEFINE_HWSERIAL_MARLIN(MSerial1, 1);
-#endif
-#if USING_SERIAL_2
-  DEFINE_HWSERIAL_MARLIN(MSerial2, 2);
-#endif
-#if USING_SERIAL_3
-  DEFINE_HWSERIAL_MARLIN(MSerial3, 3);
-#endif
+// Instantiate all UARTs even if they are not needed
+// This avoids a bunch of logic to figure out every serial
+// port which may be in use on the system.
+DEFINE_HWSERIAL_MARLIN(MSerial1, 1);
+DEFINE_HWSERIAL_MARLIN(MSerial2, 2);
+DEFINE_HWSERIAL_MARLIN(MSerial3, 3);
 #if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
-  #if USING_SERIAL_4
-    DEFINE_HWSERIAL_UART_MARLIN(MSerial4, 4);
-  #endif
-  #if USING_SERIAL_5
-    DEFINE_HWSERIAL_UART_MARLIN(MSerial5, 5);
-  #endif
+  DEFINE_HWSERIAL_UART_MARLIN(MSerial4, 4);
+  DEFINE_HWSERIAL_UART_MARLIN(MSerial5, 5);
 #endif
 
 // Check the type of each serial port by passing it to a template function.
diff --git a/Marlin/src/HAL/STM32F1/MarlinSerial.h b/Marlin/src/HAL/STM32F1/MarlinSerial.h
index 504593fb6bab..6aa94b64fff7 100644
--- a/Marlin/src/HAL/STM32F1/MarlinSerial.h
+++ b/Marlin/src/HAL/STM32F1/MarlinSerial.h
@@ -62,11 +62,10 @@ class MarlinSerial : public HardwareSerial {
   #endif
 };
 
-// Declare the required UARTs
-TERN_(USING_SERIAL_1, extern MarlinSerial MSerial1);
-TERN_(USING_SERIAL_2, extern MarlinSerial MSerial2);
-TERN_(USING_SERIAL_3, extern MarlinSerial MSerial3);
+extern MarlinSerial MSerial1;
+extern MarlinSerial MSerial2;
+extern MarlinSerial MSerial3;
 #if EITHER(STM32_HIGH_DENSITY, STM32_XL_DENSITY)
-  TERN_(USING_SERIAL_4, extern MarlinSerial MSerial4);
-  TERN_(USING_SERIAL_5, extern MarlinSerial MSerial5);
+  extern MarlinSerial MSerial4;
+  extern MarlinSerial MSerial5;
 #endif