Serial comunication protocol with arduino
A serial comunication example with a medium complex protocol:
I promise to expan it using crcs 
#define ledPin 13
#define waitForByte 200 //Time waiting for the next check of available data
#define maxItertionWaiting 20 //Maximun iteration before timeout
// Return values in checkResponse
#define errorTimeout -1
#define errorProtocol -2
#define responseOK 0
// first data to send
byte tSend1[]={0x15, 0x39, 0xF2, 0x78, 0x22, 0x11};
// first data to receive
byte tResp1[]={0x20, 0x1B, 0xF2, 0x79, 0x24, 0x11};
// second data to send
byte tSend2[]={0x25, 0x45, 0xF2, 0x7a, 0x09, 0x11};
// second data to receive
byte tResp2[]={0x30, 0xa0, 0xF2, 0x7b, 0x59, 0x11};
//buffer to put the response in
byte *LastResponse=NULL;
// Initialize everything
void setup()
{
Serial.begin(9600);
// wait a bit
delay(100);
// we will light on when the protocol finnalice ok
pinMode(ledPin, OUTPUT);
digitalWrite(ledPin, LOW);
}
// Read the response (in LastResponse
int checkResponse(byte response[],int iResponseSize)
{
int iReceivedCounter=0; // How many byte we have receive
int iReceivedValue=0;
int iIteration=0; // How many iterations we have wait for the last data
int iResult=responseOK;
if(LastResponse!=NULL) //Free memory
free(LastResponse);
LastResponse=(byte *)calloc(iResponseSize,1); //Alloc memory for new data
while(iReceivedCounter
{
if(Serial.available()>0)
{
iIteration=0;
iReceivedValue=Serial.read();
if(iReceivedValue!=response[iReceivedCounter]) // is it the waited byte?
{
iResult=errorProtocol;
break;
}
else
LastResponse[iReceivedCounter++]=(byte)iReceivedValue;
}
else
{
if(iIteration
{
delay(waitForByte); // One more try
iIteration++;
}
else
{
iResult=errorTimeout;
break;
}
}
}
return iResult;
}
void sendData(byte dataToSend[],int iSize)
{
for(int i=0;i
{
Serial.print(dataToSend[i],BYTE);
}
}
void loop()
{
int iImportantValue=0;
sendData(tSend1,6);
delay(200); // allow some time for the Serial data to be sent
if(checkResponse(tResp1,6)==responseOK)
{
sendData(tSend2,6);
delay(200); // allow some time for the Serial data to be sent
if(checkResponse(tResp2,6)==responseOK)
{
iImportantValue=LastResponse[3]*256+LastResponse[2];
digitalWrite(ledPin, HIGH);
}
}
}
I need my Arduino communicates with 25000000 inverters, but I’ve a problem with a special kind of CRC…could you tell me something about? is it possible to program an Arduino with the famous “onetopperchild”
))
Thanks for your coment cableman.
At the moment we can handle only 25 inverters more o less, but we are working very hard on it at this precise moment.
Ask to hexadeciman about the improvement in a near future.