Prosper Van / com

xbee communication for UWB quadcopter project

Dependencies:   PwmIn

com.cpp@11:d1f488302d06, 2014-04-25 (annotated)

Committer:
oprospero
Date:
Fri Apr 25 06:21:19 2014 +0000
Revision:
11:d1f488302d06
Parent:
10:ec36e1b59a39 
small updates;

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 4:7cdf299ea7a4 34 txBuffer = new queue();
oprospero 0:26a151d2c6db 35 signalStrength = 0;
oprospero 0:26a151d2c6db 36 xbeeRx.attach( this, &com::callback ); // Set callback as the interrupt handler.
oprospero 1:4f53de75bc96 37 #ifdef DEBUG
oprospero 0:26a151d2c6db 38 xbeeTx.printf("Communication.....Done\n\r");
oprospero 1:4f53de75bc96 39 #endif
oprospero 0:26a151d2c6db 40 }
oprospero 0:26a151d2c6db 41
oprospero 0:26a151d2c6db 42 /************************* bool isData() ********************************/
oprospero 0:26a151d2c6db 43 /* */
oprospero 0:26a151d2c6db 44 /*************************************************************************/
oprospero 0:26a151d2c6db 45
oprospero 0:26a151d2c6db 46 bool com::isData()
oprospero 0:26a151d2c6db 47 {
oprospero 2:bd1621102cad 48
oprospero 1:4f53de75bc96 49 return !rxBuffer->isEmpty();
oprospero 0:26a151d2c6db 50 }
oprospero 0:26a151d2c6db 51
oprospero 0:26a151d2c6db 52 /************************ void write( char ) *****************************/
oprospero 0:26a151d2c6db 53 /* Write a packet out the xbee com port. */
oprospero 0:26a151d2c6db 54 /* */
oprospero 0:26a151d2c6db 55 /* Data format byte[] */
oprospero 0:26a151d2c6db 56 /* byte[0] = command. */
oprospero 0:26a151d2c6db 57 /* byte[1] = upper 8 bits of value. */
oprospero 0:26a151d2c6db 58 /* byte[2] = lower 8 bits of value. */
oprospero 0:26a151d2c6db 59 /* byte[3] = Checksum byte[0] + byte[2]. */
oprospero 0:26a151d2c6db 60 /* byte[4] = Sequence Number. */
oprospero 0:26a151d2c6db 61 /* byte[5] = 255 End of message. */
oprospero 0:26a151d2c6db 62 /*************************************************************************/
oprospero 0:26a151d2c6db 63
oprospero 0:26a151d2c6db 64 void com::write( short command, short value )
oprospero 0:26a151d2c6db 65 {
oprospero 2:bd1621102cad 66 if (api_mode)
oprospero 2:bd1621102cad 67 {
oprospero 2:bd1621102cad 68 short hvalue = value / 128;
oprospero 2:bd1621102cad 69 short lvalue = (value % 128);
oprospero 2:bd1621102cad 70 short sum = (2*command + hvalue + 2*lvalue + value);
oprospero 2:bd1621102cad 71 short check = sum % 256;
oprospero 2:bd1621102cad 72 xbeeTx.putc( (char) 127); //Start Delimiter
oprospero 2:bd1621102cad 73
oprospero 2:bd1621102cad 74 xbeeTx.putc( (char) 0); //Frame Data Length MSB
oprospero 2:bd1621102cad 75 xbeeTx.putc( (char) 6); //Frame Data Length LSB
oprospero 2:bd1621102cad 76 //Frame Data
oprospero 2:bd1621102cad 77 xbeeTx.putc( (char) command); // Command
oprospero 2:bd1621102cad 78 xbeeTx.putc( (char) hvalue); // First 8 bits in array.
oprospero 2:bd1621102cad 79 xbeeTx.putc( (char) lvalue); // Second 8 bits in array.
oprospero 2:bd1621102cad 80 xbeeTx.putc( command + lvalue ); // Checksum array[0] + array[1].
oprospero 2:bd1621102cad 81 xbeeTx.putc( (char) value); // Sequence number.
oprospero 2:bd1621102cad 82 xbeeTx.putc( 255 ); // End of message.
oprospero 2:bd1621102cad 83
oprospero 2:bd1621102cad 84 xbeeTx.putc( (char) 255 - check); //Checksum
oprospero 2:bd1621102cad 85
oprospero 2:bd1621102cad 86 }
oprospero 2:bd1621102cad 87 else
oprospero 2:bd1621102cad 88 {
oprospero 2:bd1621102cad 89 short lvalue = (value % 128);
oprospero 2:bd1621102cad 90 xbeeTx.putc( (char)command ); // Command
oprospero 2:bd1621102cad 91 xbeeTx.putc( (char) value / 128 ); // First 8 bits in array.
oprospero 2:bd1621102cad 92 xbeeTx.putc( (char) lvalue); // Second 8 bits in array.
oprospero 2:bd1621102cad 93 xbeeTx.putc( command + lvalue ); // Checksum array[0] + array[1].
oprospero 2:bd1621102cad 94 xbeeTx.putc( (char)value ); // Sequence number.
oprospero 2:bd1621102cad 95 xbeeTx.putc( 255 ); // End of message.
oprospero 2:bd1621102cad 96 }
oprospero 0:26a151d2c6db 97 }
oprospero 0:26a151d2c6db 98
oprospero 4:7cdf299ea7a4 99 /*************************** char ackCheck() ********************************/
oprospero 0:26a151d2c6db 100 /* */
oprospero 0:26a151d2c6db 101 /*************************************************************************/
oprospero 0:26a151d2c6db 102
oprospero 3:f8e953201251 103 void com::ackCheck()
oprospero 3:f8e953201251 104 {
oprospero 4:7cdf299ea7a4 105 if( !txBuffer->isEmpty() && xbeeTx.writeable())
oprospero 3:f8e953201251 106 {
oprospero 11:d1f488302d06 107 __disable_irq();
oprospero 4:7cdf299ea7a4 108 short * pkt = txBuffer->pop();
oprospero 4:7cdf299ea7a4 109 write(pkt[0],pkt[1]); //may need to disable interrupt
oprospero 4:7cdf299ea7a4 110 delete[] pkt;
oprospero 11:d1f488302d06 111 __enable_irq();
oprospero 3:f8e953201251 112 }
oprospero 3:f8e953201251 113 }
oprospero 3:f8e953201251 114
oprospero 4:7cdf299ea7a4 115 bool com::rdy2ack()
oprospero 4:7cdf299ea7a4 116 {
oprospero 4:7cdf299ea7a4 117 return !txBuffer->isEmpty();
oprospero 4:7cdf299ea7a4 118 }
oprospero 3:f8e953201251 119
oprospero 3:f8e953201251 120 /*************************** char read() ********************************/
oprospero 3:f8e953201251 121 /* */
oprospero 3:f8e953201251 122 /*************************************************************************/
oprospero 3:f8e953201251 123
oprospero 0:26a151d2c6db 124 short * com::read()
oprospero 0:26a151d2c6db 125 {
oprospero 0:26a151d2c6db 126 if( !rxBuffer->isEmpty())
oprospero 0:26a151d2c6db 127 return rxBuffer->pop();
oprospero 0:26a151d2c6db 128
oprospero 0:26a151d2c6db 129 return NULL;
oprospero 0:26a151d2c6db 130 }
oprospero 0:26a151d2c6db 131
oprospero 0:26a151d2c6db 132 /************************ void callback() ********************************/
oprospero 0:26a151d2c6db 133 /* */
oprospero 0:26a151d2c6db 134 /*************************************************************************/
oprospero 0:26a151d2c6db 135
oprospero 0:26a151d2c6db 136 void com::callback()
oprospero 0:26a151d2c6db 137 {
oprospero 3:f8e953201251 138 __disable_irq();
oprospero 0:26a151d2c6db 139 while( xbeeRx.readable() )
oprospero 0:26a151d2c6db 140 {
oprospero 0:26a151d2c6db 141 char data = xbeeRx.getc();
oprospero 0:26a151d2c6db 142 // xbeeTx.printf("data: %d\n\r", data);
oprospero 2:bd1621102cad 143 // xbeeTx.printf("%d %d", data,(char) 255);
oprospero 2:bd1621102cad 144 // xbeeTx.putc( data );
oprospero 0:26a151d2c6db 145 if( bLength++ < BUFFERSIZE )
oprospero 0:26a151d2c6db 146 buffer[bLength] = data;
oprospero 3:f8e953201251 147 //
oprospero 3:f8e953201251 148 // xbeeTx.putc( bLength );
oprospero 3:f8e953201251 149 // xbeeTx.putc( bLength );
oprospero 3:f8e953201251 150 // xbeeTx.putc( 255 );
oprospero 10:ec36e1b59a39 151 //2nd condition ensure that we have a full size packet before building
oprospero 10:ec36e1b59a39 152 if( data == 255 && bLength > 5)
oprospero 0:26a151d2c6db 153 packetBuilder();
oprospero 0:26a151d2c6db 154 }
oprospero 3:f8e953201251 155 __enable_irq();
oprospero 0:26a151d2c6db 156 }
oprospero 0:26a151d2c6db 157
oprospero 2:bd1621102cad 158 //void com::api_callback()
oprospero 2:bd1621102cad 159 //{
oprospero 2:bd1621102cad 160 // while( xbeeRx.readable() )
oprospero 2:bd1621102cad 161 // {
oprospero 2:bd1621102cad 162 // buffer[bLength++] = xbeeRx.getc();
oprospero 2:bd1621102cad 163 // }
oprospero 2:bd1621102cad 164 //}
oprospero 2:bd1621102cad 165
oprospero 2:bd1621102cad 166
oprospero 0:26a151d2c6db 167 /********************** void packetBuilder() *****************************/
oprospero 0:26a151d2c6db 168 /* Creates a packet from the buffered data and places it in the rxBuffer */
oprospero 0:26a151d2c6db 169 /* queue to be read whenever convenient. Max value of +/- 8063. */
oprospero 0:26a151d2c6db 170 /*************************************************************************/
oprospero 0:26a151d2c6db 171
oprospero 0:26a151d2c6db 172 void com::packetBuilder()
oprospero 0:26a151d2c6db 173 {
oprospero 0:26a151d2c6db 174 char * commandData = new char[bLength];
oprospero 0:26a151d2c6db 175 commandData[4] = buffer[--bLength]; // Sequence Number.
oprospero 0:26a151d2c6db 176 commandData[3] = buffer[--bLength]; // CheckSum value.
oprospero 0:26a151d2c6db 177 commandData[2] = buffer[--bLength]; // Second 7 bits.
oprospero 0:26a151d2c6db 178 commandData[1] = buffer[--bLength]; // Fisrt 7 bits.
oprospero 0:26a151d2c6db 179 commandData[0] = buffer[--bLength]; // Command.
oprospero 0:26a151d2c6db 180
oprospero 0:26a151d2c6db 181
oprospero 0:26a151d2c6db 182 if( commandData[0] + commandData[2] == commandData[3] ) // Validate checksum.
oprospero 0:26a151d2c6db 183 {
oprospero 0:26a151d2c6db 184 short * array = new short[2];
oprospero 0:26a151d2c6db 185
oprospero 0:26a151d2c6db 186 array[0] = (short)commandData[0];
oprospero 0:26a151d2c6db 187
oprospero 0:26a151d2c6db 188 short value = (short)(commandData[1] * 128 + commandData[2]);
oprospero 0:26a151d2c6db 189
oprospero 0:26a151d2c6db 190 if( value > 8062 )
oprospero 0:26a151d2c6db 191 value = (short)value + 57344;
oprospero 0:26a151d2c6db 192
oprospero 0:26a151d2c6db 193 array[1] = value;
oprospero 0:26a151d2c6db 194 // xbeeTx.printf("Cmd: %d,\tVal: %d\n\r,",array[0],array[1]);
oprospero 0:26a151d2c6db 195 rxBuffer->add( array ); // Add to read buffer.
oprospero 2:bd1621102cad 196 // xbeeTx.putc( 255 );
oprospero 2:bd1621102cad 197 // xbeeTx.putc( 255 );
oprospero 5:4d96c8776442 198 if ( commandData[0] != 0)
oprospero 3:f8e953201251 199 {
oprospero 3:f8e953201251 200 short * ackPacket = new short[2];
oprospero 5:4d96c8776442 201 ackPacket[0] = commandData[0];
oprospero 3:f8e953201251 202 ackPacket[1] = commandData[4];
oprospero 3:f8e953201251 203 txBuffer->add( ackPacket ); // Ack the packet with sequence nuber.
oprospero 3:f8e953201251 204 }
oprospero 0:26a151d2c6db 205 }
oprospero 0:26a151d2c6db 206 delete[] commandData;
oprospero 0:26a151d2c6db 207 bLength = 0; // Reset the buffer length.
oprospero 0:26a151d2c6db 208 }
oprospero 2:bd1621102cad 209 //
oprospero 2:bd1621102cad 210 //void com::api_packetBuilder()
oprospero 2:bd1621102cad 211 //{
oprospero 2:bd1621102cad 212 //
oprospero 2:bd1621102cad 213 //}
oprospero 0:26a151d2c6db 214
oprospero 0:26a151d2c6db 215
oprospero 0:26a151d2c6db 216 /********************** bool isSignalGood() ******************************/
oprospero 0:26a151d2c6db 217 /* For future use */
oprospero 0:26a151d2c6db 218 /*************************************************************************/
oprospero 0:26a151d2c6db 219 bool com::isSignalGood()
oprospero 0:26a151d2c6db 220 {
oprospero 0:26a151d2c6db 221 signalStrength = rssi.dutycycle();
oprospero 0:26a151d2c6db 222 if (signalStrength > RSSI_THRES) return true;
oprospero 0:26a151d2c6db 223 else return false;
oprospero 0:26a151d2c6db 224 }
oprospero 0:26a151d2c6db 225
oprospero 2:bd1621102cad 226 void com::setAPImode(bool mode)
oprospero 2:bd1621102cad 227 {
oprospero 2:bd1621102cad 228 api_mode = mode;
oprospero 2:bd1621102cad 229 }
oprospero 2:bd1621102cad 230