feat: add Modbus support

lib/eModbus/src/ModbusServerRTU.h

@@ -0,0 +1,92 @@
+// =================================================================================================
+// eModbus: Copyright 2020 by Michael Harwerth, Bert Melis and the contributors to eModbus
+//               MIT license - see license.md for details
+// =================================================================================================
+#ifndef _MODBUS_SERVER_RTU_H
+#define _MODBUS_SERVER_RTU_H
+
+#include "options.h"
+
+#if HAS_FREERTOS
+
+#include <Arduino.h>
+#include "Stream.h"
+#include "ModbusServer.h"
+#include "RTUutils.h"
+
+extern "C" {
+#include <freertos/FreeRTOS.h>
+#include <freertos/task.h>
+}
+
+// Specal function signature for broadcast or sniffer listeners
+using MSRlistener = std::function<void(ModbusMessage msg)>;
+
+class ModbusServerRTU : public ModbusServer {
+public:
+  // Constructors
+  explicit ModbusServerRTU(uint32_t timeout, int rtsPin = -1);
+  ModbusServerRTU(uint32_t timeout, RTScallback rts);
+
+  // Destructor
+  ~ModbusServerRTU();
+
+  // begin: create task with RTU server to accept requests
+  void begin(Stream& serial, uint32_t baudRate, int coreID = -1);
+  void begin(HardwareSerial& serial, int coreID = -1);
+
+  // end: kill server task
+  void end();
+
+  // Toggle protocol to ModbusASCII
+  void useModbusASCII(unsigned long timeout = 1000);
+
+  // Toggle protocol to ModbusRTU
+  void useModbusRTU();
+
+  // Inquire protocol mode
+  bool isModbusASCII();
+
+  // Toggle skipping of leading 0x00 byte
+  void skipLeading0x00(bool onOff = true);
+
+  // Special case: worker to react on broadcast requests
+  void registerBroadcastWorker(MSRlistener worker);
+
+  // Even more special: register a sniffer worker
+  void registerSniffer(MSRlistener worker);
+
+protected:
+  // Prevent copy construction and assignment
+  ModbusServerRTU(ModbusServerRTU& m) = delete;
+  ModbusServerRTU& operator=(ModbusServerRTU& m) = delete;
+
+  inline void isInstance() { }           // Make class instantiable
+
+  // internal common begin function
+  void doBegin(uint32_t baudRate, int coreID);
+
+  static uint8_t instanceCounter;        // Number of RTU servers created (for task names)
+  TaskHandle_t serverTask;               // task of the started server
+  uint32_t serverTimeout;                // given timeout for receive. Does not really
+                                         // matter for a server, but is needed in 
+                                         // RTUutils. After timeout without any message
+                                         // the server will pause ~1ms and start 
+                                         // receive again.
+  Stream *MSRserial;                     // The serial interface to use
+  uint32_t MSRinterval;                  // Bus quiet time between messages
+  unsigned long MSRlastMicros;           // microsecond time stamp of last bus activity
+  int8_t MSRrtsPin;                      // GPIO number of the RS485 module's RE/DE line
+  RTScallback MRTSrts;                   // Callback to set the RTS line to HIGH/LOW
+  bool MSRuseASCII;                      // true=ModbusASCII, false=ModbusRTU
+  bool MSRskipLeadingZeroByte;           // true=first byte ignored if 0x00, false=all bytes accepted
+  MSRlistener listener;                  // Broadcast listener 
+  MSRlistener sniffer;                   // Sniffer listener 
+
+  // serve: loop function for server task
+  static void serve(ModbusServerRTU *myself);
+};
+
+#endif  // HAS_FREERTOS
+
+#endif // INCLUDE GUARD