Oskar Weigl / Kalman

Kalman filter for Eurobot

RFSRF05/RF12B.cpp@0:a0285293f6a6, 2012-03-20 (annotated)

Committer:
madcowswe
Date:
Tue Mar 20 12:43:16 2012 +0000
Revision:
0:a0285293f6a6
Algo done, vars not done

Who changed what in which revision?

UserRevisionLine numberNew contents of line
madcowswe 0:a0285293f6a6 1 #include "RF12B.h"
madcowswe 0:a0285293f6a6 2
madcowswe 0:a0285293f6a6 3 #include "RF_defs.h"
madcowswe 0:a0285293f6a6 4 #include <algorithm>
madcowswe 0:a0285293f6a6 5
madcowswe 0:a0285293f6a6 6
madcowswe 0:a0285293f6a6 7 RF12B::RF12B(PinName _SDI,
madcowswe 0:a0285293f6a6 8 PinName _SDO,
madcowswe 0:a0285293f6a6 9 PinName _SCK,
madcowswe 0:a0285293f6a6 10 PinName _NCS,
madcowswe 0:a0285293f6a6 11 PinName _NIRQ):spi(_SDI, _SDO, _SCK),
madcowswe 0:a0285293f6a6 12 NCS(_NCS), NIRQ(_NIRQ), NIRQ_in(_NIRQ), rfled(LED3) {
madcowswe 0:a0285293f6a6 13
madcowswe 0:a0285293f6a6 14 /* SPI frequency, word lenght, polarity and phase */
madcowswe 0:a0285293f6a6 15 spi.format(16,0);
madcowswe 0:a0285293f6a6 16 spi.frequency(2000000);
madcowswe 0:a0285293f6a6 17
madcowswe 0:a0285293f6a6 18 /* Set ~CS high */
madcowswe 0:a0285293f6a6 19 NCS = 1;
madcowswe 0:a0285293f6a6 20
madcowswe 0:a0285293f6a6 21 /* Initialise RF Module */
madcowswe 0:a0285293f6a6 22 init();
madcowswe 0:a0285293f6a6 23
madcowswe 0:a0285293f6a6 24 /* Setup interrupt to happen on falling edge of NIRQ */
madcowswe 0:a0285293f6a6 25 NIRQ.fall(this, &RF12B::rxISR);
madcowswe 0:a0285293f6a6 26 }
madcowswe 0:a0285293f6a6 27
madcowswe 0:a0285293f6a6 28 /* Returns the packet length if data is available in the receive buffer, 0 otherwise*/
madcowswe 0:a0285293f6a6 29 unsigned int RF12B::available() {
madcowswe 0:a0285293f6a6 30 return fifo.size();
madcowswe 0:a0285293f6a6 31 }
madcowswe 0:a0285293f6a6 32
madcowswe 0:a0285293f6a6 33 /* Reads a packet of data, with length "size" Returns false if read failed. TODO: make a metafifo to isolate packets*/
madcowswe 0:a0285293f6a6 34 bool RF12B::read(unsigned char* data, unsigned int size) {
madcowswe 0:a0285293f6a6 35 if (fifo.size() == 0) {
madcowswe 0:a0285293f6a6 36 return false;
madcowswe 0:a0285293f6a6 37 } else {
madcowswe 0:a0285293f6a6 38 unsigned int i = 0;
madcowswe 0:a0285293f6a6 39 while (fifo.size() > 0 && i < size) {
madcowswe 0:a0285293f6a6 40 data[i++] = fifo.front();
madcowswe 0:a0285293f6a6 41 fifo.pop();
madcowswe 0:a0285293f6a6 42 }
madcowswe 0:a0285293f6a6 43 return true;
madcowswe 0:a0285293f6a6 44 }
madcowswe 0:a0285293f6a6 45 }
madcowswe 0:a0285293f6a6 46
madcowswe 0:a0285293f6a6 47 /* Reads a byte of data from the receive buffer */
madcowswe 0:a0285293f6a6 48 unsigned char RF12B::read() {
madcowswe 0:a0285293f6a6 49 if (available()) {
madcowswe 0:a0285293f6a6 50 unsigned char data = fifo.front();
madcowswe 0:a0285293f6a6 51 fifo.pop();
madcowswe 0:a0285293f6a6 52 return data;
madcowswe 0:a0285293f6a6 53 } else {
madcowswe 0:a0285293f6a6 54 return 0xFF; // Error val although could also be data...
madcowswe 0:a0285293f6a6 55 }
madcowswe 0:a0285293f6a6 56 }
madcowswe 0:a0285293f6a6 57
madcowswe 0:a0285293f6a6 58 /* Sends a packet of data to the RF module for transmission TODO: Make asych*/
madcowswe 0:a0285293f6a6 59 void RF12B::write(unsigned char *data, unsigned char length) {
madcowswe 0:a0285293f6a6 60 unsigned char crc = 0;
madcowswe 0:a0285293f6a6 61
madcowswe 0:a0285293f6a6 62 /* Transmitter mode */
madcowswe 0:a0285293f6a6 63 changeMode(TX);
madcowswe 0:a0285293f6a6 64
madcowswe 0:a0285293f6a6 65 writeCmd(0x0000);
madcowswe 0:a0285293f6a6 66 send(0xAA); // PREAMBLE
madcowswe 0:a0285293f6a6 67 send(0xAA);
madcowswe 0:a0285293f6a6 68 send(0xAA);
madcowswe 0:a0285293f6a6 69 send(0x2D); // SYNC
madcowswe 0:a0285293f6a6 70 send(0xD4);
madcowswe 0:a0285293f6a6 71 /* Packet Length */
madcowswe 0:a0285293f6a6 72 send(length);
madcowswe 0:a0285293f6a6 73 crc = crc8(crc, length);
madcowswe 0:a0285293f6a6 74 send(crc);
madcowswe 0:a0285293f6a6 75 crc = crc8(crc, crc);
madcowswe 0:a0285293f6a6 76 /* Packet Data */
madcowswe 0:a0285293f6a6 77 for (unsigned char i=0; i<length; i++) {
madcowswe 0:a0285293f6a6 78 send(data[i]);
madcowswe 0:a0285293f6a6 79 crc = crc8(crc, data[i]);
madcowswe 0:a0285293f6a6 80 }
madcowswe 0:a0285293f6a6 81 send(crc);
madcowswe 0:a0285293f6a6 82 send(0xAA); // DUMMY BYTES
madcowswe 0:a0285293f6a6 83 send(0xAA);
madcowswe 0:a0285293f6a6 84 send(0xAA);
madcowswe 0:a0285293f6a6 85
madcowswe 0:a0285293f6a6 86 /* Back to receiver mode */
madcowswe 0:a0285293f6a6 87 changeMode(RX);
madcowswe 0:a0285293f6a6 88 status();
madcowswe 0:a0285293f6a6 89
madcowswe 0:a0285293f6a6 90
madcowswe 0:a0285293f6a6 91 }
madcowswe 0:a0285293f6a6 92
madcowswe 0:a0285293f6a6 93 /* Transmit a 1-byte data packet */
madcowswe 0:a0285293f6a6 94 void RF12B::write(unsigned char data) {
madcowswe 0:a0285293f6a6 95 write(&data, 1);
madcowswe 0:a0285293f6a6 96 }
madcowswe 0:a0285293f6a6 97
madcowswe 0:a0285293f6a6 98 void RF12B::write(queue<char> &data, int length) {
madcowswe 0:a0285293f6a6 99 char crc = 0;
madcowswe 0:a0285293f6a6 100 char length_byte = 0;
madcowswe 0:a0285293f6a6 101
madcowswe 0:a0285293f6a6 102 /* -1 means try to transmit everything in the queue */
madcowswe 0:a0285293f6a6 103 if(length == -1) {
madcowswe 0:a0285293f6a6 104 length = data.size();
madcowswe 0:a0285293f6a6 105 }
madcowswe 0:a0285293f6a6 106
madcowswe 0:a0285293f6a6 107 /* max length of packet is 255 */
madcowswe 0:a0285293f6a6 108 length_byte = min(length, 255);
madcowswe 0:a0285293f6a6 109
madcowswe 0:a0285293f6a6 110 /* Transmitter mode */
madcowswe 0:a0285293f6a6 111 changeMode(TX);
madcowswe 0:a0285293f6a6 112
madcowswe 0:a0285293f6a6 113 writeCmd(0x0000);
madcowswe 0:a0285293f6a6 114 send(0xAA); // PREAMBLE
madcowswe 0:a0285293f6a6 115 send(0xAA);
madcowswe 0:a0285293f6a6 116 send(0xAA);
madcowswe 0:a0285293f6a6 117 send(0x2D); // SYNC
madcowswe 0:a0285293f6a6 118 send(0xD4);
madcowswe 0:a0285293f6a6 119 /* Packet Length */
madcowswe 0:a0285293f6a6 120 send(length_byte);
madcowswe 0:a0285293f6a6 121 crc = crc8(crc, length_byte);
madcowswe 0:a0285293f6a6 122 send(crc);
madcowswe 0:a0285293f6a6 123 crc = crc8(crc, crc);
madcowswe 0:a0285293f6a6 124 /* Packet Data */
madcowswe 0:a0285293f6a6 125 for (char i=0; i<length_byte; i++) {
madcowswe 0:a0285293f6a6 126 send(data.front());
madcowswe 0:a0285293f6a6 127 crc = crc8(crc, data.front());
madcowswe 0:a0285293f6a6 128 data.pop();
madcowswe 0:a0285293f6a6 129 }
madcowswe 0:a0285293f6a6 130 send(crc);
madcowswe 0:a0285293f6a6 131 send(0xAA); // DUMMY BYTES
madcowswe 0:a0285293f6a6 132 send(0xAA);
madcowswe 0:a0285293f6a6 133 send(0xAA);
madcowswe 0:a0285293f6a6 134
madcowswe 0:a0285293f6a6 135 /* Back to receiver mode */
madcowswe 0:a0285293f6a6 136 changeMode(RX);
madcowswe 0:a0285293f6a6 137 status();
madcowswe 0:a0285293f6a6 138 }
madcowswe 0:a0285293f6a6 139
madcowswe 0:a0285293f6a6 140 /**********************************************************************
madcowswe 0:a0285293f6a6 141 * PRIVATE FUNCTIONS
madcowswe 0:a0285293f6a6 142 *********************************************************************/
madcowswe 0:a0285293f6a6 143
madcowswe 0:a0285293f6a6 144 /* Initialises the RF12B module */
madcowswe 0:a0285293f6a6 145 void RF12B::init() {
madcowswe 0:a0285293f6a6 146 /* writeCmd(0x80E7); //EL,EF,868band,12.0pF
madcowswe 0:a0285293f6a6 147 changeMode(RX);
madcowswe 0:a0285293f6a6 148 writeCmd(0xA640); //frequency select
madcowswe 0:a0285293f6a6 149 writeCmd(0xC647); //4.8kbps
madcowswe 0:a0285293f6a6 150 writeCmd(0x94A0); //VDI,FAST,134kHz,0dBm,-103dBm
madcowswe 0:a0285293f6a6 151 writeCmd(0xC2AC); //AL,!ml,DIG,DQD4
madcowswe 0:a0285293f6a6 152 writeCmd(0xCA81); //FIFO8,SYNC,!ff,DR
madcowswe 0:a0285293f6a6 153 writeCmd(0xCED4); //SYNC=2DD4
madcowswe 0:a0285293f6a6 154 writeCmd(0xC483); //@PWR,NO RSTRIC,!st,!fi,OE,EN
madcowswe 0:a0285293f6a6 155 writeCmd(0x9850); //!mp,90kHz,MAX OUT
madcowswe 0:a0285293f6a6 156 writeCmd(0xCC17); //OB1, COB0, LPX, Iddy, CDDIT&#65533;CBW0
madcowswe 0:a0285293f6a6 157 writeCmd(0xE000); //NOT USED
madcowswe 0:a0285293f6a6 158 writeCmd(0xC800); //NOT USED
madcowswe 0:a0285293f6a6 159 writeCmd(0xC040); //1.66MHz,2.2V */
madcowswe 0:a0285293f6a6 160
madcowswe 0:a0285293f6a6 161 writeCmd(
madcowswe 0:a0285293f6a6 162 RFM_CONFIG_EL |
madcowswe 0:a0285293f6a6 163 RFM_CONFIG_EF |
madcowswe 0:a0285293f6a6 164 RFM_CONFIG_BAND_433 //|
madcowswe 0:a0285293f6a6 165 //RFM_CONFIG_X_11_0pf // meh, using default
madcowswe 0:a0285293f6a6 166 );
madcowswe 0:a0285293f6a6 167
madcowswe 0:a0285293f6a6 168 // 2. Power Management Command
madcowswe 0:a0285293f6a6 169 // leave everything switched off for now
madcowswe 0:a0285293f6a6 170 /*
madcowswe 0:a0285293f6a6 171 writeCmd(
madcowswe 0:a0285293f6a6 172 RFM_POWER_MANAGEMENT // switch all off
madcowswe 0:a0285293f6a6 173 );
madcowswe 0:a0285293f6a6 174 */
madcowswe 0:a0285293f6a6 175
madcowswe 0:a0285293f6a6 176 // 3. Frequency Setting Command
madcowswe 0:a0285293f6a6 177 writeCmd(
madcowswe 0:a0285293f6a6 178 RFM_FREQUENCY |
madcowswe 0:a0285293f6a6 179 RFM_FREQ_433Band(435.7) //I totally made this value up... if someone knows where the sweetspots are in this band, tell me!
madcowswe 0:a0285293f6a6 180 );
madcowswe 0:a0285293f6a6 181
madcowswe 0:a0285293f6a6 182
madcowswe 0:a0285293f6a6 183 // 4. Data Rate Command
madcowswe 0:a0285293f6a6 184 writeCmd(RFM_DATA_RATE_9600);
madcowswe 0:a0285293f6a6 185
madcowswe 0:a0285293f6a6 186
madcowswe 0:a0285293f6a6 187 // 5. Receiver Control Command
madcowswe 0:a0285293f6a6 188 writeCmd(
madcowswe 0:a0285293f6a6 189 RFM_RX_CONTROL_P20_VDI |
madcowswe 0:a0285293f6a6 190 RFM_RX_CONTROL_VDI_FAST |
madcowswe 0:a0285293f6a6 191 //RFM_RX_CONTROL_BW(RFM_BAUD_RATE) |
madcowswe 0:a0285293f6a6 192 RFM_RX_CONTROL_BW_134 | // CHANGE THIS TO 67 TO IMPROVE RANGE! (though the bitrate must then be below 8kbaud, and fsk modulation changed)
madcowswe 0:a0285293f6a6 193 RFM_RX_CONTROL_GAIN_0 |
madcowswe 0:a0285293f6a6 194 RFM_RX_CONTROL_RSSI_103 // Might need adjustment. Datasheet says around 10^-5 bit error rate at this level and baudrate.
madcowswe 0:a0285293f6a6 195 );
madcowswe 0:a0285293f6a6 196
madcowswe 0:a0285293f6a6 197 // 6. Data Filter Command
madcowswe 0:a0285293f6a6 198 writeCmd(
madcowswe 0:a0285293f6a6 199 RFM_DATA_FILTER_AL |
madcowswe 0:a0285293f6a6 200 RFM_DATA_FILTER_ML |
madcowswe 0:a0285293f6a6 201 RFM_DATA_FILTER_DIG //|
madcowswe 0:a0285293f6a6 202 //RFM_DATA_FILTER_DQD(4)
madcowswe 0:a0285293f6a6 203 );
madcowswe 0:a0285293f6a6 204
madcowswe 0:a0285293f6a6 205 // 7. FIFO and Reset Mode Command
madcowswe 0:a0285293f6a6 206 writeCmd(
madcowswe 0:a0285293f6a6 207 RFM_FIFO_IT(8) |
madcowswe 0:a0285293f6a6 208 RFM_FIFO_DR |
madcowswe 0:a0285293f6a6 209 0x8 //turn on 16bit sync word
madcowswe 0:a0285293f6a6 210 );
madcowswe 0:a0285293f6a6 211
madcowswe 0:a0285293f6a6 212 // 8. FIFO Syncword
madcowswe 0:a0285293f6a6 213 // Leave as default: 0xD4
madcowswe 0:a0285293f6a6 214
madcowswe 0:a0285293f6a6 215 // 9. Receiver FIFO Read
madcowswe 0:a0285293f6a6 216 // when the interupt goes high, (and if we can assume that it was a fifo fill interrupt) we can read a byte using:
madcowswe 0:a0285293f6a6 217 // result = RFM_READ_FIFO();
madcowswe 0:a0285293f6a6 218
madcowswe 0:a0285293f6a6 219 // 10. AFC Command
madcowswe 0:a0285293f6a6 220 writeCmd(
madcowswe 0:a0285293f6a6 221 //RFM_AFC_AUTO_VDI | //Note this might be changed to improve range. Refer to datasheet.
madcowswe 0:a0285293f6a6 222 RFM_AFC_AUTO_INDEPENDENT |
madcowswe 0:a0285293f6a6 223 RFM_AFC_RANGE_LIMIT_7_8 |
madcowswe 0:a0285293f6a6 224 RFM_AFC_EN |
madcowswe 0:a0285293f6a6 225 RFM_AFC_OE |
madcowswe 0:a0285293f6a6 226 RFM_AFC_FI
madcowswe 0:a0285293f6a6 227 );
madcowswe 0:a0285293f6a6 228
madcowswe 0:a0285293f6a6 229 // 11. TX Configuration Control Command
madcowswe 0:a0285293f6a6 230 writeCmd(
madcowswe 0:a0285293f6a6 231 RFM_TX_CONTROL_MOD_60 |
madcowswe 0:a0285293f6a6 232 RFM_TX_CONTROL_POW_0
madcowswe 0:a0285293f6a6 233 );
madcowswe 0:a0285293f6a6 234
madcowswe 0:a0285293f6a6 235
madcowswe 0:a0285293f6a6 236 // 12. PLL Setting Command
madcowswe 0:a0285293f6a6 237 writeCmd(
madcowswe 0:a0285293f6a6 238 0xCC77 & ~0x01 // Setting the PLL bandwith, less noise, but max bitrate capped at 86.2
madcowswe 0:a0285293f6a6 239 // I think this will slow down the pll's reaction time. Not sure, check with someone!
madcowswe 0:a0285293f6a6 240 );
madcowswe 0:a0285293f6a6 241
madcowswe 0:a0285293f6a6 242 changeMode(RX);
madcowswe 0:a0285293f6a6 243 resetRX();
madcowswe 0:a0285293f6a6 244 status();
madcowswe 0:a0285293f6a6 245 }
madcowswe 0:a0285293f6a6 246
madcowswe 0:a0285293f6a6 247 /* Write a command to the RF Module */
madcowswe 0:a0285293f6a6 248 unsigned int RF12B::writeCmd(unsigned int cmd) {
madcowswe 0:a0285293f6a6 249 NCS = 0;
madcowswe 0:a0285293f6a6 250 unsigned int recv = spi.write(cmd);
madcowswe 0:a0285293f6a6 251 NCS = 1;
madcowswe 0:a0285293f6a6 252 return recv;
madcowswe 0:a0285293f6a6 253 }
madcowswe 0:a0285293f6a6 254
madcowswe 0:a0285293f6a6 255 /* Sends a byte of data across RF */
madcowswe 0:a0285293f6a6 256 void RF12B::send(unsigned char data) {
madcowswe 0:a0285293f6a6 257 while (NIRQ);
madcowswe 0:a0285293f6a6 258 writeCmd(0xB800 + data);
madcowswe 0:a0285293f6a6 259 }
madcowswe 0:a0285293f6a6 260
madcowswe 0:a0285293f6a6 261 /* Change the mode of the RF module to Transmitting or Receiving */
madcowswe 0:a0285293f6a6 262 void RF12B::changeMode(rfmode_t _mode) {
madcowswe 0:a0285293f6a6 263 mode = _mode;
madcowswe 0:a0285293f6a6 264 if (_mode == TX) {
madcowswe 0:a0285293f6a6 265 writeCmd(0x8239); //!er,!ebb,ET,ES,EX,!eb,!ew,DC
madcowswe 0:a0285293f6a6 266 } else { /* mode == RX */
madcowswe 0:a0285293f6a6 267 writeCmd(0x8299); //er,!ebb,ET,ES,EX,!eb,!ew,DC
madcowswe 0:a0285293f6a6 268 }
madcowswe 0:a0285293f6a6 269 }
madcowswe 0:a0285293f6a6 270
madcowswe 0:a0285293f6a6 271 /* Interrupt routine for data reception */
madcowswe 0:a0285293f6a6 272 void RF12B::rxISR() {
madcowswe 0:a0285293f6a6 273 unsigned int data = 0;
madcowswe 0:a0285293f6a6 274 static int i = -2;
madcowswe 0:a0285293f6a6 275 static unsigned char packet_length = 0;
madcowswe 0:a0285293f6a6 276 static unsigned char crc = 0;
madcowswe 0:a0285293f6a6 277 static queue<unsigned char> temp;
madcowswe 0:a0285293f6a6 278
madcowswe 0:a0285293f6a6 279 //Loop while interrupt is asserted
madcowswe 0:a0285293f6a6 280 while (!NIRQ_in && mode == RX) {
madcowswe 0:a0285293f6a6 281
madcowswe 0:a0285293f6a6 282 /* Grab the packet's length byte */
madcowswe 0:a0285293f6a6 283 if (i == -2) {
madcowswe 0:a0285293f6a6 284 data = writeCmd(0x0000);
madcowswe 0:a0285293f6a6 285 if ( (data&0x8000) ) {
madcowswe 0:a0285293f6a6 286 data = writeCmd(0xB000);
madcowswe 0:a0285293f6a6 287 packet_length = (data&0x00FF);
madcowswe 0:a0285293f6a6 288 crc = crc8(crc, packet_length);
madcowswe 0:a0285293f6a6 289 i++;
madcowswe 0:a0285293f6a6 290 }
madcowswe 0:a0285293f6a6 291 }
madcowswe 0:a0285293f6a6 292
madcowswe 0:a0285293f6a6 293 //If we exhaust the interrupt, exit
madcowswe 0:a0285293f6a6 294 if (NIRQ_in)
madcowswe 0:a0285293f6a6 295 break;
madcowswe 0:a0285293f6a6 296
madcowswe 0:a0285293f6a6 297 // Check that packet length was correct
madcowswe 0:a0285293f6a6 298 if (i == -1) {
madcowswe 0:a0285293f6a6 299 data = writeCmd(0x0000);
madcowswe 0:a0285293f6a6 300 if ( (data&0x8000) ) {
madcowswe 0:a0285293f6a6 301 data = writeCmd(0xB000);
madcowswe 0:a0285293f6a6 302 unsigned char crcofsize = (data&0x00FF);
madcowswe 0:a0285293f6a6 303 if (crcofsize != crc) {
madcowswe 0:a0285293f6a6 304 //It was wrong, start over
madcowswe 0:a0285293f6a6 305 i = -2;
madcowswe 0:a0285293f6a6 306 packet_length = 0;
madcowswe 0:a0285293f6a6 307 crc = 0;
madcowswe 0:a0285293f6a6 308 temp = queue<unsigned char>();
madcowswe 0:a0285293f6a6 309 resetRX();
madcowswe 0:a0285293f6a6 310 } else {
madcowswe 0:a0285293f6a6 311 crc = crc8(crc, crcofsize);
madcowswe 0:a0285293f6a6 312 i++;
madcowswe 0:a0285293f6a6 313 }
madcowswe 0:a0285293f6a6 314 }
madcowswe 0:a0285293f6a6 315 }
madcowswe 0:a0285293f6a6 316
madcowswe 0:a0285293f6a6 317 //If we exhaust the interrupt, exit
madcowswe 0:a0285293f6a6 318 if (NIRQ_in)
madcowswe 0:a0285293f6a6 319 break;
madcowswe 0:a0285293f6a6 320
madcowswe 0:a0285293f6a6 321 /* Grab the packet's data */
madcowswe 0:a0285293f6a6 322 if (i >= 0 && i < packet_length) {
madcowswe 0:a0285293f6a6 323 data = writeCmd(0x0000);
madcowswe 0:a0285293f6a6 324 if ( (data&0x8000) ) {
madcowswe 0:a0285293f6a6 325 data = writeCmd(0xB000);
madcowswe 0:a0285293f6a6 326 temp.push(data&0x00FF);
madcowswe 0:a0285293f6a6 327 crc = crc8(crc, (unsigned char)(data&0x00FF));
madcowswe 0:a0285293f6a6 328 i++;
madcowswe 0:a0285293f6a6 329 }
madcowswe 0:a0285293f6a6 330 }
madcowswe 0:a0285293f6a6 331
madcowswe 0:a0285293f6a6 332 //If we exhaust the interrupt, exit
madcowswe 0:a0285293f6a6 333 if (NIRQ_in)
madcowswe 0:a0285293f6a6 334 break;
madcowswe 0:a0285293f6a6 335
madcowswe 0:a0285293f6a6 336 if (i >= packet_length) {
madcowswe 0:a0285293f6a6 337 data = writeCmd(0x0000);
madcowswe 0:a0285293f6a6 338 if ( (data&0x8000) ) {
madcowswe 0:a0285293f6a6 339 data = writeCmd(0xB000);
madcowswe 0:a0285293f6a6 340 if ((unsigned char)(data & 0x00FF) == crc) {
madcowswe 0:a0285293f6a6 341 //If the checksum is correct, add our data to the end of the output buffer
madcowswe 0:a0285293f6a6 342 while (!temp.empty()) {
madcowswe 0:a0285293f6a6 343 fifo.push(temp.front());
madcowswe 0:a0285293f6a6 344 temp.pop();
madcowswe 0:a0285293f6a6 345 }
madcowswe 0:a0285293f6a6 346 }
madcowswe 0:a0285293f6a6 347
madcowswe 0:a0285293f6a6 348 /* Tell RF Module we are finished, and clean up */
madcowswe 0:a0285293f6a6 349 i = -2;
madcowswe 0:a0285293f6a6 350 packet_length = 0;
madcowswe 0:a0285293f6a6 351 crc = 0;
madcowswe 0:a0285293f6a6 352 temp = queue<unsigned char>();
madcowswe 0:a0285293f6a6 353 resetRX();
madcowswe 0:a0285293f6a6 354 }
madcowswe 0:a0285293f6a6 355 }
madcowswe 0:a0285293f6a6 356 }
madcowswe 0:a0285293f6a6 357 }
madcowswe 0:a0285293f6a6 358
madcowswe 0:a0285293f6a6 359 unsigned int RF12B::status() {
madcowswe 0:a0285293f6a6 360 return writeCmd(0x0000);
madcowswe 0:a0285293f6a6 361 }
madcowswe 0:a0285293f6a6 362
madcowswe 0:a0285293f6a6 363 /* Tell the RF Module this packet is received and wait for the next */
madcowswe 0:a0285293f6a6 364 void RF12B::resetRX() {
madcowswe 0:a0285293f6a6 365 writeCmd(0xCA81);
madcowswe 0:a0285293f6a6 366 writeCmd(0xCA83);
madcowswe 0:a0285293f6a6 367 };
madcowswe 0:a0285293f6a6 368
madcowswe 0:a0285293f6a6 369 /* Calculate CRC8 */
madcowswe 0:a0285293f6a6 370 unsigned char RF12B::crc8(unsigned char crc, unsigned char data) {
madcowswe 0:a0285293f6a6 371 crc = crc ^ data;
madcowswe 0:a0285293f6a6 372 for (int i = 0; i < 8; i++) {
madcowswe 0:a0285293f6a6 373 if (crc & 0x01) {
madcowswe 0:a0285293f6a6 374 crc = (crc >> 1) ^ 0x8C;
madcowswe 0:a0285293f6a6 375 } else {
madcowswe 0:a0285293f6a6 376 crc >>= 1;
madcowswe 0:a0285293f6a6 377 }
madcowswe 0:a0285293f6a6 378 }
madcowswe 0:a0285293f6a6 379 return crc;
madcowswe 0:a0285293f6a6 380 }