Fix #17 Pass Stream object to ModbusMaster

- BREAK: This is a breaking change to the interface. ModbusMaster now takes a serial object which has been initialized with the appropriate baud rate. Any Stream object may be used, including SoftwareSerial. - As a byproduct of these changes, the library should now be able to be used on other architectures besides AVR and SAM.
4-20ma · May 24, 2015 · 9e611e3 · 9e611e3
1 parent 799a8ef
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diff --git a/ModbusMaster.cpp b/ModbusMaster.cpp
@@ -33,120 +33,39 @@ Arduino library for communicating with Modbus slaves over RS232/485 (via RTU pro
 
 
 /* _____GLOBAL VARIABLES_____________________________________________________ */
-#if defined(ARDUINO_ARCH_AVR)
-  HardwareSerial* MBSerial = &Serial; ///< Pointer to Serial class object
-#elif defined(ARDUINO_ARCH_SAM)
-  UARTClass* MBSerial = &Serial; ///< Pointer to Serial class object
-#else
-  #error "This library only supports boards with an AVR or SAM processor. Please open an issue at https://github.com/4-20ma/ModbusMaster/issues and indicate which processor/platform you're using."
-#endif
 
 
 /* _____PUBLIC FUNCTIONS_____________________________________________________ */
 /**
 Constructor.
 
-Creates class object using default serial port 0, Modbus slave ID 1.
+Creates class object; initialize it using ModbusMaster::begin().
 
 @ingroup setup
 */
 ModbusMaster::ModbusMaster(void)
 {
-  _u8SerialPort = 0;
-  _u8MBSlave = 1;
-}
-
-
-/**
-Constructor.
-
-Creates class object using default serial port 0, specified Modbus slave ID.
-
-@overload void ModbusMaster::ModbusMaster(uint8_t u8MBSlave)
-@param u8MBSlave Modbus slave ID (1..255)
-@ingroup setup
-*/
-ModbusMaster::ModbusMaster(uint8_t u8MBSlave)
-{
-  _u8SerialPort = 0;
-  _u8MBSlave = u8MBSlave;
-}
-
-
-/**
-Constructor.
-
-Creates class object using specified serial port, Modbus slave ID.
-
-@overload void ModbusMaster::ModbusMaster(uint8_t u8SerialPort, uint8_t u8MBSlave)
-@param u8SerialPort serial port (Serial, Serial1..Serial3)
-@param u8MBSlave Modbus slave ID (1..255)
-@ingroup setup
-*/
-ModbusMaster::ModbusMaster(uint8_t u8SerialPort, uint8_t u8MBSlave)
-{
-  _u8SerialPort = (u8SerialPort > 3) ? 0 : u8SerialPort;
-  _u8MBSlave = u8MBSlave;
-}
-
-
-/**
-Initialize class object.
-
-Sets up the serial port using default 19200 baud rate.
-Call once class has been instantiated, typically within setup().
-
-@ingroup setup
-*/
-void ModbusMaster::begin(void)
-{
-  begin(19200);
 }
 
 
 /**
 Initialize class object.
 
-Sets up the serial port using specified baud rate.
+Assigns the Modbus slave ID and serial port.
 Call once class has been instantiated, typically within setup().
 
-@overload ModbusMaster::begin(uint16_t u16BaudRate)
-@param u16BaudRate baud rate, in standard increments (300..115200)
+@param slave Modbus slave ID (1..255)
+@param &serial reference to serial port object (Serial, Serial1, ... Serial3)
 @ingroup setup
 */
-void ModbusMaster::begin(uint16_t u16BaudRate)
+void ModbusMaster::begin(uint8_t slave, Stream &serial)
 {
 //  txBuffer = (uint16_t*) calloc(ku8MaxBufferSize, sizeof(uint16_t));
+  _u8MBSlave = slave;
+  _serial = &serial;
   _u8TransmitBufferIndex = 0;
   u16TransmitBufferLength = 0;
 
-  switch(_u8SerialPort)
-  {
-#if defined(UBRR1H)
-    case 1:
-      MBSerial = &Serial1;
-      break;
-#endif
-
-#if defined(UBRR2H)
-    case 2:
-      MBSerial = &Serial2;
-      break;
-#endif
-
-#if defined(UBRR3H)
-    case 3:
-      MBSerial = &Serial3;
-      break;
-#endif
-
-    case 0:
-    default:
-      MBSerial = &Serial;
-      break;
-  }
-
-  MBSerial->begin(u16BaudRate);
 #if __MODBUSMASTER_DEBUG__
   pinMode(4, OUTPUT);
   pinMode(5, OUTPUT);
@@ -750,31 +669,31 @@ uint8_t ModbusMaster::ModbusMasterTransaction(uint8_t u8MBFunction)
   u8ModbusADU[u8ModbusADUSize] = 0;
 
   // flush receive buffer before transmitting request
-  while (MBSerial->read() != -1);
+  while (_serial->read() != -1);
 
   // transmit request
   for (i = 0; i < u8ModbusADUSize; i++)
   {
 #if defined(ARDUINO) && ARDUINO >= 100
-    MBSerial->write(u8ModbusADU[i]);
+    _serial->write(u8ModbusADU[i]);
 #else
-    MBSerial->print(u8ModbusADU[i], BYTE);
+    _serial->print(u8ModbusADU[i], BYTE);
 #endif
   }
 
   u8ModbusADUSize = 0;
-  MBSerial->flush();    // flush transmit buffer
+  _serial->flush();    // flush transmit buffer
 
   // loop until we run out of time or bytes, or an error occurs
   u32StartTime = millis();
   while (u8BytesLeft && !u8MBStatus)
   {
-    if (MBSerial->available())
+    if (_serial->available())
     {
 #if __MODBUSMASTER_DEBUG__
       digitalWrite(4, true);
 #endif
-      u8ModbusADU[u8ModbusADUSize++] = MBSerial->read();
+      u8ModbusADU[u8ModbusADUSize++] = _serial->read();
       u8BytesLeft--;
 #if __MODBUSMASTER_DEBUG__
       digitalWrite(4, false);

diff --git a/ModbusMaster.h b/ModbusMaster.h
@@ -75,11 +75,8 @@ class ModbusMaster
 {
   public:
     ModbusMaster();
-    ModbusMaster(uint8_t);
-    ModbusMaster(uint8_t, uint8_t);
 
-    void begin();
-    void begin(uint16_t);
+    void begin(uint8_t, Stream &serial);
     void idle(void (*)());
 
     // Modbus exception codes
@@ -224,9 +221,8 @@ class ModbusMaster
     uint8_t  readWriteMultipleRegisters(uint16_t, uint16_t);
 
   private:
-    uint8_t  _u8SerialPort;                                      ///< serial port (0..3) initialized in constructor
-    uint8_t  _u8MBSlave;                                         ///< Modbus slave (1..255) initialized in constructor
-    uint16_t _u16BaudRate;                                       ///< baud rate (300..115200) initialized in begin()
+    Stream* _serial;                                             ///< reference to serial port object
+    uint8_t  _u8MBSlave;                                         ///< Modbus slave (1..255) initialized in begin()
     static const uint8_t ku8MaxBufferSize                = 64;   ///< size of response/transmit buffers    
     uint16_t _u16ReadAddress;                                    ///< slave register from which to read
     uint16_t _u16ReadQty;                                        ///< quantity of words to read

diff --git a/README.md b/README.md
@@ -88,22 +88,24 @@ The library contains a few sketches that demonstrate use of the ModbusMaster lib
   along with ModbusMaster.  If not, see <http://www.gnu.org/licenses/>.
 
   Written by Doc Walker (Rx)
-  Copyright © 2009-2013 Doc Walker <4-20ma at wvfans dot net>
+  Copyright © 2009-2015 Doc Walker <4-20ma at wvfans dot net>
 
 */
 
 #include <ModbusMaster.h>
 
 
-// instantiate ModbusMaster object as slave ID 2
-// defaults to serial port 0 since no port was specified
-ModbusMaster node(2);
+// instantiate ModbusMaster object
+ModbusMaster node;
 
 
 void setup()
 {
-  // initialize Modbus communication baud rate
-  node.begin(19200);
+  // use Serial (port 0); initialize Modbus communication baud rate
+  Serial.begin(19200);
+
+  // communicate with Modbus slave ID 2 over Serial (port 0)
+  node.begin(2, Serial);
 }
 
 

diff --git a/examples/Basic/Basic.pde b/examples/Basic/Basic.pde
@@ -18,22 +18,24 @@
   along with ModbusMaster.  If not, see <http://www.gnu.org/licenses/>.
   
   Written by Doc Walker (Rx)
-  Copyright © 2009-2013 Doc Walker <4-20ma at wvfans dot net>
+  Copyright © 2009-2015 Doc Walker <4-20ma at wvfans dot net>
   
 */
 
 #include <ModbusMaster.h>
 
 
-// instantiate ModbusMaster object as slave ID 2
-// defaults to serial port 0 since no port was specified
-ModbusMaster node(2);
+// instantiate ModbusMaster object
+ModbusMaster node;
 
 
 void setup()
 {
-  // initialize Modbus communication baud rate
-  node.begin(19200);
+  // use Serial (port 0); initialize Modbus communication baud rate
+  Serial.begin(19200);
+
+  // communicate with Modbus slave ID 2 over Serial (port 0)
+  node.begin(2, Serial);
 }
 
 
@@ -66,4 +68,3 @@ void loop()
     }
   }
 }
-
diff --git a/examples/PhoenixContact_nanoLC/PhoenixContact_nanoLC.pde b/examples/PhoenixContact_nanoLC/PhoenixContact_nanoLC.pde
@@ -19,7 +19,7 @@
   along with ModbusMaster.  If not, see <http://www.gnu.org/licenses/>.
   
   Written by Doc Walker (Rx)
-  Copyright © 2009-2013 Doc Walker <4-20ma at wvfans dot net>
+  Copyright © 2009-2015 Doc Walker <4-20ma at wvfans dot net>
   
 */
 
@@ -46,14 +46,17 @@
 #define NANO_AI(n)   (0x0000 + 2 * n) ///< returns nanoLC analog input address
 
 
-// instantiate ModbusMaster object, serial port 0, Modbus slave ID 1
-ModbusMaster nanoLC(0, 1);
+// instantiate ModbusMaster object
+ModbusMaster nanoLC;
 
 
 void setup()
 {
-  // initialize Modbus communication baud rate
-  nanoLC.begin(19200);
+  // use Serial (port 0); initialize Modbus communication baud rate
+  Serial.begin(19200);
+
+  // communicate with Modbus slave ID 1 over Serial (port 0)
+  nanoLC.begin(1, Serial);
 }
 
 

diff --git a/keywords.txt b/keywords.txt
@@ -7,7 +7,6 @@
 #######################################
 
 ModbusMaster	KEYWORD1
-MBSerial	KEYWORD1
 
 #######################################
 # Methods and Functions (KEYWORD2)

diff --git a/library.properties b/library.properties
@@ -6,4 +6,4 @@ sentence=Enlighten your Arduino to be a Modbus master.
 paragraph=Enables communication with Modbus slaves over RS232/485 (via RTU protocol). Requires an RS232/485 transceiver.
 category=Communication
 url=https://github.com/4-20ma/ModbusMaster
-architectures=avr,sam
+architectures=*