Prosper Van / xbeeCom

xbee communication for UWB quadcopter project Originally by Greg Abdo Forking to reduce impact of interrupt by moving packetbuilder out of the interrupt and letting be handled in the main loop

Fork of com by Prosper Van

com.cpp@3:42e37cdab039, 2014-04-20 (annotated)

Committer:
oprospero
Date:
Sun Apr 20 17:08:47 2014 +0000
Revision:
3:42e37cdab039
Parent:
2:bd1621102cad 
Changed commands to switch statements

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 3:42e37cdab039 116 __disable_irq();
oprospero 0:26a151d2c6db 117 while( xbeeRx.readable() )
oprospero 0:26a151d2c6db 118 {
oprospero 0:26a151d2c6db 119 char data = xbeeRx.getc();
oprospero 0:26a151d2c6db 120 // xbeeTx.printf("data: %d\n\r", data);
oprospero 2:bd1621102cad 121 // xbeeTx.printf("%d %d", data,(char) 255);
oprospero 2:bd1621102cad 122 // xbeeTx.putc( data );
oprospero 0:26a151d2c6db 123 if( bLength++ < BUFFERSIZE )
oprospero 0:26a151d2c6db 124 buffer[bLength] = data;
oprospero 0:26a151d2c6db 125
oprospero 0:26a151d2c6db 126 if( data == 255 )
oprospero 0:26a151d2c6db 127 packetBuilder();
oprospero 0:26a151d2c6db 128 }
oprospero 3:42e37cdab039 129 __enable_irq();
oprospero 0:26a151d2c6db 130 }
oprospero 0:26a151d2c6db 131
oprospero 2:bd1621102cad 132 //void com::api_callback()
oprospero 2:bd1621102cad 133 //{
oprospero 2:bd1621102cad 134 // while( xbeeRx.readable() )
oprospero 2:bd1621102cad 135 // {
oprospero 2:bd1621102cad 136 // buffer[bLength++] = xbeeRx.getc();
oprospero 2:bd1621102cad 137 // }
oprospero 2:bd1621102cad 138 //}
oprospero 2:bd1621102cad 139
oprospero 2:bd1621102cad 140
oprospero 0:26a151d2c6db 141 /********************** void packetBuilder() *****************************/
oprospero 0:26a151d2c6db 142 /* Creates a packet from the buffered data and places it in the rxBuffer */
oprospero 0:26a151d2c6db 143 /* queue to be read whenever convenient. Max value of +/- 8063. */
oprospero 0:26a151d2c6db 144 /*************************************************************************/
oprospero 0:26a151d2c6db 145
oprospero 0:26a151d2c6db 146 void com::packetBuilder()
oprospero 0:26a151d2c6db 147 {
oprospero 0:26a151d2c6db 148 char * commandData = new char[bLength];
oprospero 0:26a151d2c6db 149 commandData[4] = buffer[--bLength]; // Sequence Number.
oprospero 0:26a151d2c6db 150 commandData[3] = buffer[--bLength]; // CheckSum value.
oprospero 0:26a151d2c6db 151 commandData[2] = buffer[--bLength]; // Second 7 bits.
oprospero 0:26a151d2c6db 152 commandData[1] = buffer[--bLength]; // Fisrt 7 bits.
oprospero 0:26a151d2c6db 153 commandData[0] = buffer[--bLength]; // Command.
oprospero 0:26a151d2c6db 154
oprospero 0:26a151d2c6db 155
oprospero 0:26a151d2c6db 156 if( commandData[0] + commandData[2] == commandData[3] ) // Validate checksum.
oprospero 0:26a151d2c6db 157 {
oprospero 0:26a151d2c6db 158 short * array = new short[2];
oprospero 0:26a151d2c6db 159
oprospero 0:26a151d2c6db 160 array[0] = (short)commandData[0];
oprospero 0:26a151d2c6db 161
oprospero 0:26a151d2c6db 162 short value = (short)(commandData[1] * 128 + commandData[2]);
oprospero 0:26a151d2c6db 163
oprospero 0:26a151d2c6db 164 if( value > 8062 )
oprospero 0:26a151d2c6db 165 value = (short)value + 57344;
oprospero 0:26a151d2c6db 166
oprospero 0:26a151d2c6db 167 array[1] = value;
oprospero 0:26a151d2c6db 168 // xbeeTx.printf("Cmd: %d,\tVal: %d\n\r,",array[0],array[1]);
oprospero 0:26a151d2c6db 169 rxBuffer->add( array ); // Add to read buffer.
oprospero 2:bd1621102cad 170 // xbeeTx.putc( 255 );
oprospero 2:bd1621102cad 171 // xbeeTx.putc( 255 );
oprospero 0:26a151d2c6db 172 write( (short)commandData[0], (short)commandData[4]); // Ack the packet with sequence nuber.
oprospero 0:26a151d2c6db 173 }
oprospero 0:26a151d2c6db 174 delete[] commandData;
oprospero 0:26a151d2c6db 175 bLength = 0; // Reset the buffer length.
oprospero 0:26a151d2c6db 176 }
oprospero 2:bd1621102cad 177 //
oprospero 2:bd1621102cad 178 //void com::api_packetBuilder()
oprospero 2:bd1621102cad 179 //{
oprospero 2:bd1621102cad 180 //
oprospero 2:bd1621102cad 181 //}
oprospero 0:26a151d2c6db 182
oprospero 0:26a151d2c6db 183
oprospero 0:26a151d2c6db 184 /********************** bool isSignalGood() ******************************/
oprospero 0:26a151d2c6db 185 /* For future use */
oprospero 0:26a151d2c6db 186 /*************************************************************************/
oprospero 0:26a151d2c6db 187 bool com::isSignalGood()
oprospero 0:26a151d2c6db 188 {
oprospero 0:26a151d2c6db 189 signalStrength = rssi.dutycycle();
oprospero 0:26a151d2c6db 190 if (signalStrength > RSSI_THRES) return true;
oprospero 0:26a151d2c6db 191 else return false;
oprospero 0:26a151d2c6db 192 }
oprospero 0:26a151d2c6db 193
oprospero 2:bd1621102cad 194 void com::setAPImode(bool mode)
oprospero 2:bd1621102cad 195 {
oprospero 2:bd1621102cad 196 api_mode = mode;
oprospero 2:bd1621102cad 197 }
oprospero 2:bd1621102cad 198