DevelopmentCode/RS485.cpp at master · LPRD/DevelopmentCode · GitHub

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#include<RS485.h>
#include"Arduino.h"

SoftwareSerial rs485 (RX_PIN, TX_PIN);

voidfWrite (const byte what)
{
 rs485.write (what);
//Serial.print((int)what);
//Serial.print(' ');
}

intfAvailable ()
{
return rs485.available ();
}

intfRead ()
{
return rs485.read ();
}


byte crc8 (constchar *addr)
{
 byte len = 0;
while((byte)addr[len] != '\0')
 {
 len++;
 }

 byte crc = 0;
while (len--)
 {
 byte inbyte = *addr++;
for (byte i = 8; i; i--)
 {
 byte mix = (crc ^ inbyte) & 0x01;
 crc >>= 1;
if (mix)
 crc ^= 0x8C;
 inbyte >>= 1;
 } // end of for
 } // end of while
return crc;
} // end of crc8

voidEncodeMessage(char message[maxMsgLen+1], unsignedchar data[maxMsgLen+1+3])
{
int index=0;
int index2 = 0;

 data[index] = STX;

while(message[index2] != '\0')
 {
 index++;
 data[index] = (char)message[index2];
 index2++;
 }

 index++;
 data[index] = ETX;

 index++;
 data[index] = (char)crc8(message);

 index++;
 data[index] = '\0';
}

voidRS485_Begin(int baud)
{
pinMode(ENABLE_PIN, OUTPUT); // driver output enable
	rs485.begin(baud);
}


boolRS485_SendMessage(char message[maxMsgLen+1],WriteCallback fWrite,int EnablePin)
{
unsignedchar temp[maxMsgLen+1+2];

EncodeMessage(message,temp);

digitalWrite (EnablePin, HIGH); // enable sending
int counter =0;
while(temp[counter] != '\0')
 {
fWrite(temp[counter]);
	counter++;
 }

delay(1); // Delay abit or else the RS485 will switch off before the last byte has been sent.
digitalWrite (EnablePin, LOW); // disable sending
returntrue;
}

boolRS485_ReadMessage(AvailableCallback fAvailable, ReadCallback fRead, char data[maxMsgLen+3+1])
{
bool bSTX = false;
bool bETX = false;

 byte index = 0;
int input = -1;

 byte CRC=0;

if(fAvailable())
 {
while(fAvailable())
 {
 input = fRead();

switch(input)
 {
// Start of message
caseSTX :
 bSTX = true;
 index = 0;
break;

// End of message
caseETX :
 bETX = true;
break;

default:

if(!bSTX)
// Don't read if the message has not started
break;
else
 {

// While not the end of the message keep collection bytes
if(!bETX)
 {
 data[index] = input;
 index++;
if(index >= maxMsgLen+3+1)
 {
returnfalse;
 }
 data[index] = '\0';

 }
else
 {
CRC = input;
 }
 }
 }
delay(1); // Delay a bit or you will reach the end of the buffer before its even been filled.
 }

if(CRC != crc8(data))
 {
returnfalse;
 }
returntrue;
 }
returnfalse;
}

// For test the bytes comming in
boolRS485_ReadPlainMessage(AvailableCallback fAvailable, ReadCallback fRead, char message[maxMsgLen+3+1])
{
if(fAvailable())
 {
int input = -1;
int counter=0;
while(fAvailable())
 {
 input = fRead();
 message[counter] = input;
 counter++;
 message[counter] = '\0';
delay(1); // Delay a bit or you will reach the end of the buffer before its even been filled.
 }
returntrue;
 }
returnfalse;
}