Prosper Van / com

xbee communication for UWB quadcopter project

Dependencies:   PwmIn

com.cpp@2:bd1621102cad, 2014-04-20 (annotated)

Committer:
oprospero
Date:
Sun Apr 20 02:27:39 2014 +0000
Revision:
2:bd1621102cad
Parent:
1:4f53de75bc96
Child:
3:f8e953201251
Child:
8:42e37cdab039
clean ups

Who changed what in which revision?

UserRevisionLine numberNew contents of line
oprospero 0:26a151d2c6db 1 /****************************** com.cpp **********************************/
oprospero 0:26a151d2c6db 2 /* Version: 1.0 */
oprospero 0:26a151d2c6db 3 /* Last Updated: June 1, 2013 */
oprospero 0:26a151d2c6db 4 /* */
oprospero 0:26a151d2c6db 5 /* The com class implements reliable data transfer between two nodes */
oprospero 0:26a151d2c6db 6 /*using a checksum and a sequence number for guaranteed message delivery */
oprospero 0:26a151d2c6db 7 /*over an xbee modem connected to the passed in tx and rx pins. Messages */
oprospero 0:26a151d2c6db 8 /*are received and placed in the rxBuffer to be read when convenient. */
oprospero 0:26a151d2c6db 9 /*Messages are encoded by sending a byte with the value of the command */
oprospero 0:26a151d2c6db 10 /*then and int of the command. */
oprospero 0:26a151d2c6db 11 /* */
oprospero 0:26a151d2c6db 12 /* Commands: 0 -> Ack, does not get placed in rxQueue. */
oprospero 0:26a151d2c6db 13 /* 1 -> Throttle */
oprospero 0:26a151d2c6db 14 /* 2 -> Pitch */
oprospero 0:26a151d2c6db 15 /* 3 -> Roll */
oprospero 0:26a151d2c6db 16 /* 4 -> Yaw */
oprospero 0:26a151d2c6db 17 /*************************************************************************/
oprospero 0:26a151d2c6db 18
oprospero 0:26a151d2c6db 19 #include "mbed.h"
oprospero 0:26a151d2c6db 20 #include "com.h"
oprospero 0:26a151d2c6db 21
oprospero 1:4f53de75bc96 22
oprospero 0:26a151d2c6db 23 /*********************** com( PinName, PinName ) *************************/
oprospero 0:26a151d2c6db 24 /* */
oprospero 0:26a151d2c6db 25 /*************************************************************************/
oprospero 0:26a151d2c6db 26
oprospero 2:bd1621102cad 27 com::com( PinName tx, PinName rx , PinName rssipin) : xbeeTx( tx, NC), xbeeRx( NC, rx), rssi(rssipin)
oprospero 0:26a151d2c6db 28 {
oprospero 0:26a151d2c6db 29 bLength = 0; // How many bytes are in the buffer.
oprospero 2:bd1621102cad 30 api_mode = false; // Xbee is in transparent mode.
oprospero 1:4f53de75bc96 31 xbeeTx.baud(BAUDRATE); // Setup the serial baud rate.
oprospero 0:26a151d2c6db 32 xbeeRx.baud(BAUDRATE); // Setup the serial baud rate.
oprospero 0:26a151d2c6db 33 rxBuffer = new queue(); // Point to the rxQueue.
oprospero 0:26a151d2c6db 34 signalStrength = 0;
oprospero 0:26a151d2c6db 35 xbeeRx.attach( this, &com::callback ); // Set callback as the interrupt handler.
oprospero 1:4f53de75bc96 36 #ifdef DEBUG
oprospero 0:26a151d2c6db 37 xbeeTx.printf("Communication.....Done\n\r");
oprospero 1:4f53de75bc96 38 #endif
oprospero 0:26a151d2c6db 39 }
oprospero 0:26a151d2c6db 40
oprospero 0:26a151d2c6db 41 /************************* bool isData() ********************************/
oprospero 0:26a151d2c6db 42 /* */
oprospero 0:26a151d2c6db 43 /*************************************************************************/
oprospero 0:26a151d2c6db 44
oprospero 0:26a151d2c6db 45 bool com::isData()
oprospero 0:26a151d2c6db 46 {
oprospero 2:bd1621102cad 47
oprospero 1:4f53de75bc96 48 return !rxBuffer->isEmpty();
oprospero 0:26a151d2c6db 49 }
oprospero 0:26a151d2c6db 50
oprospero 0:26a151d2c6db 51 /************************ void write( char ) *****************************/
oprospero 0:26a151d2c6db 52 /* Write a packet out the xbee com port. */
oprospero 0:26a151d2c6db 53 /* */
oprospero 0:26a151d2c6db 54 /* Data format byte[] */
oprospero 0:26a151d2c6db 55 /* byte[0] = command. */
oprospero 0:26a151d2c6db 56 /* byte[1] = upper 8 bits of value. */
oprospero 0:26a151d2c6db 57 /* byte[2] = lower 8 bits of value. */
oprospero 0:26a151d2c6db 58 /* byte[3] = Checksum byte[0] + byte[2]. */
oprospero 0:26a151d2c6db 59 /* byte[4] = Sequence Number. */
oprospero 0:26a151d2c6db 60 /* byte[5] = 255 End of message. */
oprospero 0:26a151d2c6db 61 /*************************************************************************/
oprospero 0:26a151d2c6db 62
oprospero 0:26a151d2c6db 63 void com::write( short command, short value )
oprospero 0:26a151d2c6db 64 {
oprospero 2:bd1621102cad 65 if (api_mode)
oprospero 2:bd1621102cad 66 {
oprospero 2:bd1621102cad 67 short hvalue = value / 128;
oprospero 2:bd1621102cad 68 short lvalue = (value % 128);
oprospero 2:bd1621102cad 69 short sum = (2*command + hvalue + 2*lvalue + value);
oprospero 2:bd1621102cad 70 short check = sum % 256;
oprospero 2:bd1621102cad 71 xbeeTx.putc( (char) 127); //Start Delimiter
oprospero 2:bd1621102cad 72
oprospero 2:bd1621102cad 73 xbeeTx.putc( (char) 0); //Frame Data Length MSB
oprospero 2:bd1621102cad 74 xbeeTx.putc( (char) 6); //Frame Data Length LSB
oprospero 2:bd1621102cad 75 //Frame Data
oprospero 2:bd1621102cad 76 xbeeTx.putc( (char) command); // Command
oprospero 2:bd1621102cad 77 xbeeTx.putc( (char) hvalue); // First 8 bits in array.
oprospero 2:bd1621102cad 78 xbeeTx.putc( (char) lvalue); // Second 8 bits in array.
oprospero 2:bd1621102cad 79 xbeeTx.putc( command + lvalue ); // Checksum array[0] + array[1].
oprospero 2:bd1621102cad 80 xbeeTx.putc( (char) value); // Sequence number.
oprospero 2:bd1621102cad 81 xbeeTx.putc( 255 ); // End of message.
oprospero 2:bd1621102cad 82
oprospero 2:bd1621102cad 83 xbeeTx.putc( (char) 255 - check); //Checksum
oprospero 2:bd1621102cad 84
oprospero 2:bd1621102cad 85 }
oprospero 2:bd1621102cad 86 else
oprospero 2:bd1621102cad 87 {
oprospero 2:bd1621102cad 88 short lvalue = (value % 128);
oprospero 2:bd1621102cad 89 xbeeTx.putc( (char)command ); // Command
oprospero 2:bd1621102cad 90 xbeeTx.putc( (char) value / 128 ); // First 8 bits in array.
oprospero 2:bd1621102cad 91 xbeeTx.putc( (char) lvalue); // Second 8 bits in array.
oprospero 2:bd1621102cad 92 xbeeTx.putc( command + lvalue ); // Checksum array[0] + array[1].
oprospero 2:bd1621102cad 93 xbeeTx.putc( (char)value ); // Sequence number.
oprospero 2:bd1621102cad 94 xbeeTx.putc( 255 ); // End of message.
oprospero 2:bd1621102cad 95 }
oprospero 0:26a151d2c6db 96 }
oprospero 0:26a151d2c6db 97
oprospero 0:26a151d2c6db 98 /*************************** char read() ********************************/
oprospero 0:26a151d2c6db 99 /* */
oprospero 0:26a151d2c6db 100 /*************************************************************************/
oprospero 0:26a151d2c6db 101
oprospero 0:26a151d2c6db 102 short * com::read()
oprospero 0:26a151d2c6db 103 {
oprospero 0:26a151d2c6db 104 if( !rxBuffer->isEmpty())
oprospero 0:26a151d2c6db 105 return rxBuffer->pop();
oprospero 0:26a151d2c6db 106
oprospero 0:26a151d2c6db 107 return NULL;
oprospero 0:26a151d2c6db 108 }
oprospero 0:26a151d2c6db 109
oprospero 0:26a151d2c6db 110 /************************ void callback() ********************************/
oprospero 0:26a151d2c6db 111 /* */
oprospero 0:26a151d2c6db 112 /*************************************************************************/
oprospero 0:26a151d2c6db 113
oprospero 0:26a151d2c6db 114 void com::callback()
oprospero 0:26a151d2c6db 115 {
oprospero 0:26a151d2c6db 116 while( xbeeRx.readable() )
oprospero 0:26a151d2c6db 117 {
oprospero 0:26a151d2c6db 118 char data = xbeeRx.getc();
oprospero 0:26a151d2c6db 119 // xbeeTx.printf("data: %d\n\r", data);
oprospero 2:bd1621102cad 120 // xbeeTx.printf("%d %d", data,(char) 255);
oprospero 2:bd1621102cad 121 // xbeeTx.putc( data );
oprospero 0:26a151d2c6db 122 if( bLength++ < BUFFERSIZE )
oprospero 0:26a151d2c6db 123 buffer[bLength] = data;
oprospero 0:26a151d2c6db 124
oprospero 0:26a151d2c6db 125 if( data == 255 )
oprospero 0:26a151d2c6db 126 packetBuilder();
oprospero 0:26a151d2c6db 127 }
oprospero 0:26a151d2c6db 128 }
oprospero 0:26a151d2c6db 129
oprospero 2:bd1621102cad 130 //void com::api_callback()
oprospero 2:bd1621102cad 131 //{
oprospero 2:bd1621102cad 132 // while( xbeeRx.readable() )
oprospero 2:bd1621102cad 133 // {
oprospero 2:bd1621102cad 134 // buffer[bLength++] = xbeeRx.getc();
oprospero 2:bd1621102cad 135 // }
oprospero 2:bd1621102cad 136 //}
oprospero 2:bd1621102cad 137
oprospero 2:bd1621102cad 138
oprospero 0:26a151d2c6db 139 /********************** void packetBuilder() *****************************/
oprospero 0:26a151d2c6db 140 /* Creates a packet from the buffered data and places it in the rxBuffer */
oprospero 0:26a151d2c6db 141 /* queue to be read whenever convenient. Max value of +/- 8063. */
oprospero 0:26a151d2c6db 142 /*************************************************************************/
oprospero 0:26a151d2c6db 143
oprospero 0:26a151d2c6db 144 void com::packetBuilder()
oprospero 0:26a151d2c6db 145 {
oprospero 0:26a151d2c6db 146 char * commandData = new char[bLength];
oprospero 0:26a151d2c6db 147 commandData[4] = buffer[--bLength]; // Sequence Number.
oprospero 0:26a151d2c6db 148 commandData[3] = buffer[--bLength]; // CheckSum value.
oprospero 0:26a151d2c6db 149 commandData[2] = buffer[--bLength]; // Second 7 bits.
oprospero 0:26a151d2c6db 150 commandData[1] = buffer[--bLength]; // Fisrt 7 bits.
oprospero 0:26a151d2c6db 151 commandData[0] = buffer[--bLength]; // Command.
oprospero 0:26a151d2c6db 152
oprospero 0:26a151d2c6db 153
oprospero 0:26a151d2c6db 154 if( commandData[0] + commandData[2] == commandData[3] ) // Validate checksum.
oprospero 0:26a151d2c6db 155 {
oprospero 0:26a151d2c6db 156 short * array = new short[2];
oprospero 0:26a151d2c6db 157
oprospero 0:26a151d2c6db 158 array[0] = (short)commandData[0];
oprospero 0:26a151d2c6db 159
oprospero 0:26a151d2c6db 160 short value = (short)(commandData[1] * 128 + commandData[2]);
oprospero 0:26a151d2c6db 161
oprospero 0:26a151d2c6db 162 if( value > 8062 )
oprospero 0:26a151d2c6db 163 value = (short)value + 57344;
oprospero 0:26a151d2c6db 164
oprospero 0:26a151d2c6db 165 array[1] = value;
oprospero 0:26a151d2c6db 166 // xbeeTx.printf("Cmd: %d,\tVal: %d\n\r,",array[0],array[1]);
oprospero 0:26a151d2c6db 167 rxBuffer->add( array ); // Add to read buffer.
oprospero 2:bd1621102cad 168 // xbeeTx.putc( 255 );
oprospero 2:bd1621102cad 169 // xbeeTx.putc( 255 );
oprospero 0:26a151d2c6db 170 write( (short)commandData[0], (short)commandData[4]); // Ack the packet with sequence nuber.
oprospero 0:26a151d2c6db 171 }
oprospero 0:26a151d2c6db 172 delete[] commandData;
oprospero 0:26a151d2c6db 173 bLength = 0; // Reset the buffer length.
oprospero 0:26a151d2c6db 174 }
oprospero 2:bd1621102cad 175 //
oprospero 2:bd1621102cad 176 //void com::api_packetBuilder()
oprospero 2:bd1621102cad 177 //{
oprospero 2:bd1621102cad 178 //
oprospero 2:bd1621102cad 179 //}
oprospero 0:26a151d2c6db 180
oprospero 0:26a151d2c6db 181
oprospero 0:26a151d2c6db 182 /********************** bool isSignalGood() ******************************/
oprospero 0:26a151d2c6db 183 /* For future use */
oprospero 0:26a151d2c6db 184 /*************************************************************************/
oprospero 0:26a151d2c6db 185 bool com::isSignalGood()
oprospero 0:26a151d2c6db 186 {
oprospero 0:26a151d2c6db 187 signalStrength = rssi.dutycycle();
oprospero 0:26a151d2c6db 188 if (signalStrength > RSSI_THRES) return true;
oprospero 0:26a151d2c6db 189 else return false;
oprospero 0:26a151d2c6db 190 }
oprospero 0:26a151d2c6db 191
oprospero 2:bd1621102cad 192 void com::setAPImode(bool mode)
oprospero 2:bd1621102cad 193 {
oprospero 2:bd1621102cad 194 api_mode = mode;
oprospero 2:bd1621102cad 195 }
oprospero 2:bd1621102cad 196