File content as of revision 2:b4d1f5424448:

#include "communication_1.h"
#include "mbed.h"

#define READ_DEBUG 1

communication_1::communication_1(PinName tx, PinName rx, int baud_rate) 
: _SerialHalfDuplex(tx,rx) {
        
   _SerialHalfDuplex.baud(baud_rate);
}

int communication_1::read(int ID, int start, int bytes, char* data) {

    char PacketLength = 0x4;
    char TxBuf[16];
    char sum = 0;
    char Status[16];

    Status[4] = 0xFE; // return code

    TxBuf[0] = 0xff;
    TxBuf[1] = 0xff;

    // ID
    TxBuf[2] = ID;
    sum += TxBuf[2];

    // Packet Length
    TxBuf[3] = PacketLength;    // Length = 4 ; 2 + 1 (start) = 1 (bytes)
    sum += TxBuf[3];            // Accululate the packet sum

    // Instruction - Read
    TxBuf[4] = 0x2;
    sum += TxBuf[4];

    // Start Address
    TxBuf[5] = start;
    sum += TxBuf[5];
  
    // Bytes to read
    TxBuf[6] = bytes;
    sum += TxBuf[6];
   
    // Checksum
    TxBuf[7] = 0xFF - sum;

    // Transmit the packet in one burst with no pausing
    for (int i = 0; i<8 ; i++) {
       // printf("Inizio scrittura numero %d\n",i);
        _SerialHalfDuplex.putc(TxBuf[i]);
         //printf("Fine scrittura numero %d\n",i);
    }

    // Wait for the bytes to be transmitted
    wait (0.00002);

    // Skip if the read was to the broadcast address
    if (ID != 0xFE) {
        // Receive the Status packet 6+ number of bytes read
        for (int i=0; i<(6+bytes) ; i++) {
            Status[i] = _SerialHalfDuplex.getc();
        }

        // Copy the data from Status into data for return
        for (int i=0; i < Status[3]-2 ; i++) {
            data[i] = Status[5+i];
            }
            
        if (READ_DEBUG) {
                printf("\nStatus Packet\n");
                printf("  Header : 0x%x\n",Status[0]);
                printf("  Header : 0x%x\n",Status[1]);
                printf("  ID : 0x%x\n",Status[2]);
                printf("  Length : 0x%x\n",Status[3]);
                printf("  Error Code : 0x%x\n",Status[4]);
    
                for (int i=0; i < Status[3]-2 ; i++) {
                    printf("  Data : 0x%x\n",Status[5+i]);
                }    
                printf("  Checksum : 0x%x\n",Status[5+(Status[3]-2)]);
            }            
    } // if (ID!=0xFE)
    
    return(Status[4]);
}


int communication_1::write(int ID, int start, int bytes, char* data, int flag) {
// 0xff, 0xff, ID, Length, Intruction(write), Address, Param(s), Checksum

    char TxBuf[16];
    char sum = 0;
    char Status[6];

    TxBuf[0] = 0xff;
    TxBuf[1] = 0xff;

    // ID
    TxBuf[2] = ID;
    sum += TxBuf[2];

    // packet Length
    TxBuf[3] = 3+bytes;
    sum += TxBuf[3];

    // Instruction
    if (flag == 1) {
        TxBuf[4]=0x04;
        sum += TxBuf[4];
    } else {
        TxBuf[4]=0x03;
        sum += TxBuf[4];
    }

    // Start Address
    TxBuf[5] = start;
    sum += TxBuf[5];
    
    // data
    for (int i=0; i<bytes ; i++) {
        TxBuf[6+i] = data[i];
        sum += TxBuf[6+i];
    }

    // checksum
    TxBuf[6+bytes] = 0xFF - sum;

    // Transmit the packet in one burst with no pausing
    for (int i = 0; i < (7 + bytes) ; i++) {
        _SerialHalfDuplex.putc(TxBuf[i]);
    }

    // Wait for data to transmit
    wait (0.00002);

    // make sure we have a valid return
    Status[4]=0x00;

    // we'll only get a reply if it was not broadcast
    if (ID!=0xFE) {
        // response is always 6 bytes
        // 0xFF, 0xFF, ID, Length Error, Param(s) Checksum
        for (int i=0; i < 6 ; i++) {
            Status[i] = _SerialHalfDuplex.getc();
        }
        
 return(Status[4]); // return error code

}}