File content as of revision 15:3f742edaa359:

/****************************** com.cpp **********************************/
/* Version: 1.0                                                          */
/* Last Updated: June 1, 2013                                            */
/*                                                                       */
/* The com class implements reliable data transfer between two nodes     */
/*using a checksum and a sequence number for guaranteed message delivery */
/*over an xbee modem connected to the passed in tx and rx pins. Messages */
/*are received and placed in the rxBuffer to be read when convenient.    */
/*Messages are encoded by sending a byte with the value of the command   */
/*then and int of the command.                                           */
/*                                                                       */
/* Commands:    0 -> Ack, does not get placed in rxQueue.                */
/*              1 -> Throttle                                            */
/*              2 -> Pitch                                               */
/*              3 -> Roll                                                */
/*              4 -> Yaw                                                 */
/*************************************************************************/

#include "com.h"
#ifdef DEBUG_COM
    Timer timerCom;
    #define NL "\n\r"
    #define PRINT(x) xbeeTx.printf(x)   //Serial.print(x)
    #define PRINTF(x, y) xbeeTx.printf( (x) ,(y) )   //Serial.print(x, y)
    #define PRINTLN(x) PRINT(x);PRINT(NL)
    #define PRINTLNF(x, y) PRINTF((x) ,(y));PRINT(NL)
    #define START timerCom.start(); 
    #define STOP timerCom.stop()
    #define RESET timerCom.reset()
    #define READ timerCom.read_us()
    #define GET(x) x = READ
#else
    #define PRINT(x)
    #define PRINTF(x, y)
    #define PRINTLN(x)
    #define PRINTLNF(x, y) 
    #define START 
    #define STOP  
    #define RESET 
    #define READ 
    #define GET(x)
#endif


/*********************** com( PinName, PinName ) *************************/
/*                                                                       */
/*************************************************************************/

com::com( PinName tx, PinName rx , PinName rssipin) : xbeeTx( tx, NC), xbeeRx( NC, rx), rssi(rssipin)
{
    index1 = 0;                             // How many bytes are in the buffer.
    index2 = 0;                             // How many bytes are in the buffer.
    pindex = 0;                             // How many bytes are in the buffer.
    rdy2build = false;                      // Xbee is in transparent mode.
    xbeeTx.baud(BAUDRATE);                  // Setup the serial baud rate.
    xbeeRx.baud(BAUDRATE);                  // Setup the serial baud rate.
    txBuffer = new queue();
    signalStrength = 0;
    xbeeRx.attach( this, &com::callback );    // Set callback as the interrupt handler. 
    #ifdef DEBUG_COM
    xbeeTx.printf("Communication.....Done\n\r");
    #endif
    START;
}

/************************* bool isData()  ********************************/
/*                                                                       */
/*************************************************************************/

//bool com::isData()
//{
//    return rdy2build;
//}

bool com::isData()
{
    static short packetIndex = 0;
    static short pack_cmd = 0;
    static short pack_value[2] = {0,0};
    static short pack_seq = 0;
    static short pack_checksum = 0;
    while ( !rxBuffer->isEmpty() )
    {
        short * data = rxBuffer->pop();
        switch (packetIndex)
        {
            case 0:
            {
                if ( *data == 255 )
                packetIndex++;
                break;
            }
            case 1:
            {
                if ( *data < 13 )
                {
                    pack_cmd = *data;
                    packetIndex++;
                }
                else
                    packetIndex = 0;
                break;
            }
            case 2:
            {
                pack_value[1] = *data;
                packetIndex++;
                break;
            }
            case 3:
            {
                pack_value[0] = *data;
                packetIndex++;
                break;
            }
            case 4:
            {
                pack_seq = *data;
                packetIndex++;
                break;   
            }
            case 5:
            {
                short temp = pack_value[0] + pack_cmd;
                pack_checksum = *data;
                if ( temp == pack_checksum )
                {
                    short * ackPacket = new short[2];
                    ackPacket[0] = pack_cmd;
                    ackPacket[1] = pack_seq;
                    txBuffer->add( ackPacket ); // Ack the packet with sequence nuber.
                    
                    short * array = new short[2];
                    array[0] = pack_cmd;
                    array[1] = pack_value[1] * 128 + pack_value[0];
                    cmdBuffer->add( array );
                }
                
                packetIndex = 0;
                break;   
            }
            default:
            packetIndex = 0;
            break;
        }
        
    }
    return !cmdBuffer->isEmpty();
}

/************************ void write( char ) *****************************/
/* Write a packet out the xbee com port.                                 */
/*                                                                       */
/* Data format byte[]                                                    */
/*                byte[0] = command.                                     */
/*                byte[1] = upper 8 bits of value.                       */
/*                byte[2] = lower 8 bits of value.                       */
/*                byte[3] = Checksum byte[0] + byte[2].                  */
/*                byte[4] = Sequence Number.                             */
/*                byte[5] = 255 End of message.                          */
/*************************************************************************/

void com::write( short command, short value  )
{  
    xbeeTx.putc( 255 );                     // End of message.
    xbeeTx.putc( (char)command );           // Command
    xbeeTx.putc( (char) value);            // Second 8 bits in array.
    xbeeTx.putc( command + value );        // Checksum array[0] + array[1].
}

/*************************** char ackCheck()  ********************************/
/*                                                                       */
/*************************************************************************/

void com::sendACK()
{
    if( !txBuffer->isEmpty())
    {
    __disable_irq();
        short * pkt = txBuffer->pop();
    __enable_irq();
        write(pkt[0],pkt[1]); //may need to disable interrupt
//        #ifdef DEBUG_COM
        if(pkt[1] % 5 == 0) 
        {
            PRINTLNF("len: %d",txBuffer->queueLength());
            xbeeTx.printf("len: %d\n\r",txBuffer->queueLength());
        }
//        #endif
        delete[] pkt;
    
    }
}

bool com::rdy2ack()
{
    return !txBuffer->isEmpty();
}



/************************ void callback() ********************************/
/*                                                                       */
/*************************************************************************/

//void com::callback()
//{   
//    __disable_irq();
//    while( xbeeRx.readable() )
//    {
//        char data = xbeeRx.getc(); 
////        xbeeRx.putc(data);
//        if (isA1)
//        {
//            if ( data == 255 && index1 > 4 )
//            {
//                rdy2build = true;
//                pindex = index1;
//                index1 = 0;
//                isA1 = false;
//            }
//            else if ( index1 < BUFFERSIZE )
//            {
//                
//                buffer1[index1++] = data;
//            }
//        }
//        else
//        {
//            if ( data == 255 && index2 > 4 )
//            {
//                rdy2build = true;
//                pindex = index2;
//                index2 = 0;
//                isA1 = true;
//            }
//            else if ( index2 < BUFFERSIZE )
//            {
//                buffer2[index2++] = data;
//            }
//        }
//    }
//    __enable_irq();
//}

void com::callback()
{   
    __disable_irq();
    while( xbeeRx.readable() )
    {
        short *data = new short;
        *data = xbeeRx.getc(); 
        
        rxBuffer->add( data );
    }
    __enable_irq();
}

/********************** void packetBuilder() *****************************/
/* Creates a packet from the buffered data and places it in the rxBuffer */
/* queue to be read whenever convenient. Max value of +/- 8063.          */
/*************************************************************************/

//short * com::read()
//{
//    if (rdy2build)
//    {
//        rdy2build = false;
//        char * commandData = new char[5];
//        if (!isA1)
//        {
//            commandData[4] = buffer1[--pindex];     // Sequence Number.
//            commandData[3] = buffer1[--pindex];     // CheckSum value.
//            commandData[2] = buffer1[--pindex];     // Second 7 bits.
//            commandData[1] = buffer1[--pindex];     // Fisrt 7 bits.
//            commandData[0] = buffer1[--pindex];     // Command.
//        }
//        else 
//        {
//            commandData[4] = buffer2[--pindex];     // Sequence Number.
//            commandData[3] = buffer2[--pindex];     // CheckSum value.
//            commandData[2] = buffer2[--pindex];     // Second 7 bits.
//            commandData[1] = buffer2[--pindex];     // Fisrt 7 bits.
//            commandData[0] = buffer2[--pindex];     // Command.
//        }
//        
////        xbeeTx.printf("Copied: %d %d %d %d %d\n\r",commandData[0],commandData[1],commandData[2],commandData[3],commandData[4]);
//          
//        if( commandData[0] + commandData[2] == commandData[3] ) // Validate checksum.
//        {
//            short * array = new short[2];
//            array[0] = (short)commandData[0];
//            
//            short value = (short)(commandData[1] * 128 + commandData[2]);
//            
//            if( value > 8062 )
//                value = (short)value + 57344;
//            
//            array[1] = value;
//            if ( commandData[0] != 0)
//            {
//                short * ackPacket = new short[2];
//                ackPacket[0] = commandData[0];
//                ackPacket[1] = commandData[4];
//                txBuffer->add( ackPacket ); // Ack the packet with sequence nuber.
//            }
//            
//            delete[] commandData;
//            return array;
//        } 
//        delete[] commandData; 
//    }        
//    return NULL;                                 
//}

short * com::read()
{
    if ( !cmdBuffer->isEmpty() )
        return cmdBuffer->pop();
    else
        return NULL;    
}


/********************** bool isSignalGood() ******************************/
/* For future use   */
/*************************************************************************/
bool com::isSignalGood()
{
    signalStrength = rssi.dutycycle();
    if (signalStrength > RSSI_THRES) return true;
    else return false;
}