Explicitly specify pins for Serial1 too

buildroot/share/PlatformIO/variants/BIGTREE_SKR_PRO_1v1/variant.h

@@ -253,11 +253,13 @@ extern "C" {
 #define TIMER_SERVO             TIM6  //TODO: advanced-control timers don't work
 
 // UART Definitions
+//#define ENABLE_HWSERIAL1        done automatically by the #define SERIAL_UART_INSTANCE below
 #define ENABLE_HWSERIAL3
 #define ENABLE_HWSERIAL6
 
 // Define here Serial instance number to map on Serial generic name
-#define SERIAL_UART_INSTANCE    1 //ex: 2 for Serial2 (USART2)
+#define SERIAL_UART_INSTANCE    1 //1 for Serial = Serial1 (USART1)
+
 // DEBUG_UART could be redefined to print on another instance than 'Serial'
 //#define DEBUG_UART              ((USART_TypeDef *) U(S)ARTX) // ex: USART3
 // DEBUG_UART baudrate, default: 9600 if not defined
@@ -269,10 +271,13 @@ extern "C" {
 // Mandatory for Firmata
 #define PIN_SERIAL_RX           PA10
 #define PIN_SERIAL_TX           PA9
+
 // Optional PIN_SERIALn_RX and PIN_SERIALn_TX where 'n' is the U(S)ART number
 // Used when user instanciate a hardware Serial using its peripheral name.
 // Example: HardwareSerial mySerial(USART3);
 // will use PIN_SERIAL3_RX and PIN_SERIAL3_TX if defined.
+#define PIN_SERIAL1_RX          PA10
+#define PIN_SERIAL1_TX          PA9
 #define PIN_SERIAL3_RX          PD9
 #define PIN_SERIAL3_TX          PD8
 #define PIN_SERIAL6_RX          PC7