Gustavo González / SimpleModbusSlave

SimpleModbusSlave allows you to communicate to any slave using the Modbus RTU protocol. The crc calculation is based on https://os.mbed.com/users/jpelletier/code/CRC/ The functions implemented are functions 3 and 16. read holding registers and preset multiple registers of the Modbus RTU Protocol. This implementation DOES NOT fully comply with the Modbus specifications.

Files at this revision

API Documentation at this revision

Revision 1:85e226914fb7, committed 2017-10-25

Comitter:
gugani
Date:
Wed Oct 25 10:38:11 2017 +0000
Parent:
0:7c5265097fd2
Commit message:
Initial commit

Changed in this revision

SimpleModbusSlave.cpp Show annotated file Show diff for this revision Revisions of this file
SimpleModbusSlave.h Show annotated file Show diff for this revision Revisions of this file 
diff -r 7c5265097fd2 -r 85e226914fb7 SimpleModbusSlave.cpp
--- a/SimpleModbusSlave.cpp	Tue Oct 10 12:22:31 2017 +0000
+++ b/SimpleModbusSlave.cpp	Wed Oct 25 10:38:11 2017 +0000
@@ -18,6 +18,8 @@
 unsigned int T1_5; // inter character time out
 unsigned int T3_5; // frame delay
 unsigned char buffer = 0;
+unsigned char datarec = 0;
+unsigned char datasent = 0;
 
 Timer intercharacter_timer;
 Timeout interframe_timeout;
@@ -33,10 +35,27 @@
 void sendPacket(unsigned char bufferSize);
 unsigned int reverse_CRC(unsigned int calculated_CRC);
 
+unsigned int newdatarec(){
+    if (datarec){
+        datarec = 0;
+        return 1;
+    }
+    else return 0;
+}
+
+unsigned int newdatasent(){
+    if (datasent){
+        datasent = 0;
+        return 1;
+    }
+    else return 0;
+}
+
 void end_of_transmission()
 {
     if (TxEnablePin > 1)
         dir = 0;
+    datasent = 1;
 }
 
 unsigned int modbus_update(unsigned int *holdingRegs)
@@ -85,6 +104,7 @@
                 unsigned int crc = ((frame[buffer - 2] << 8) | frame[buffer - 1]); // combine the crc Low & High bytes                
                 if (reverse_CRC(calculate_crc16_Modbus(frame, buffer - 2)) == crc) // if the calculated crc matches the recieved crc continue
                 {                    
+                    datarec = 1;
                     function = frame[1];
                     unsigned int startingAddress = ((frame[2] << 8) | frame[3]); // combine the starting address bytes
                     unsigned int no_of_registers = ((frame[4] << 8) | frame[5]); // combine the number of register bytes  

diff -r 7c5265097fd2 -r 85e226914fb7 SimpleModbusSlave.h
--- a/SimpleModbusSlave.h	Tue Oct 10 12:22:31 2017 +0000
+++ b/SimpleModbusSlave.h	Wed Oct 25 10:38:11 2017 +0000
@@ -84,6 +84,7 @@
 // function definitions
 void modbus_configure(long baud, char _slaveID, char _TxEnablePin, unsigned int _holdingRegsSize, unsigned char _lowLatency);
 unsigned int modbus_update(unsigned int *holdingRegs);
- 
+unsigned int newdatarec(void);
+unsigned int newdatasent(void);
 
 #endif