cvs.zerfleddert.de Git - proxmark3-svn/blob - armsrc/lfsampling.c

   1 //-----------------------------------------------------------------------------
   2 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
   3 // at your option, any later version. See the LICENSE.txt file for the text of
   4 // the license.
   5 //-----------------------------------------------------------------------------
   6 // Miscellaneous routines for low frequency sampling.
   7 //-----------------------------------------------------------------------------
   8
   9 #include "lfsampling.h"
  10
  11 /*
  12 Default LF config is set to:
  13         decimation = 1  (we keep 1 out of 1 samples)
  14         bits_per_sample = 8
  15         averaging = YES
  16         divisor = 95 (125khz)
  17         trigger_threshold = 0
  18         */
  19 sample_config config = { 1, 8, 1, 95, 0 } ;
  20
  21 void printConfig() {
  22         Dbprintf("LF Sampling config: ");
  23         Dbprintf("  [q] divisor:           %d ", config.divisor);
  24         Dbprintf("  [b] bps:               %d ", config.bits_per_sample);
  25         Dbprintf("  [d] decimation:        %d ", config.decimation);
  26         Dbprintf("  [a] averaging:         %s ", (config.averaging) ? "Yes" : "No");
  27         Dbprintf("  [t] trigger threshold: %d ", config.trigger_threshold);
  28 }
  29
  30 /**
  31  * Called from the USB-handler to set the sampling configuration
  32  * The sampling config is used for std reading and snooping.
  33  *
  34  * Other functions may read samples and ignore the sampling config,
  35  * such as functions to read the UID from a prox tag or similar.
  36  *
  37  * Values set to '0' implies no change (except for averaging)
  38  * @brief setSamplingConfig
  39  * @param sc
  40  */
  41 void setSamplingConfig(sample_config *sc) {
  42         if(sc->divisor != 0) config.divisor = sc->divisor;
  43         if(sc->bits_per_sample != 0) config.bits_per_sample = sc->bits_per_sample;
  44         if(sc->trigger_threshold != -1) config.trigger_threshold = sc->trigger_threshold;
  45
  46         config.decimation = (sc->decimation != 0) ? sc->decimation : 1;
  47         config.averaging = sc->averaging;
  48         if(config.bits_per_sample > 8)  config.bits_per_sample = 8;
  49
  50         printConfig();
  51 }
  52
  53 sample_config* getSamplingConfig() {
  54         return &config;
  55 }
  56
  57 struct BitstreamOut {
  58         uint8_t * buffer;
  59         uint32_t numbits;
  60         uint32_t position;
  61 };
  62
  63 /**
  64  * @brief Pushes bit onto the stream
  65  * @param stream
  66  * @param bit
  67  */
  68 void pushBit( BitstreamOut* stream, uint8_t bit) {
  69         int bytepos = stream->position >> 3; // divide by 8
  70         int bitpos = stream->position & 7;
  71         *(stream->buffer+bytepos) |= (bit > 0) <<  (7 - bitpos);
  72         stream->position++;
  73         stream->numbits++;
  74 }
  75
  76 /**
  77 * Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
  78 * if not already loaded, sets divisor and starts up the antenna.
  79 * @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
  80 *                                  0 or 95 ==> 125 KHz
  81 *
  82 **/
  83 void LFSetupFPGAForADC(int divisor, bool lf_field) {
  84         FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
  85         if ( (divisor == 1) || (divisor < 0) || (divisor > 255) )
  86                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
  87         else if (divisor == 0)
  88                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
  89         else
  90                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
  91
  92         FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
  93
  94         // Connect the A/D to the peak-detected low-frequency path.
  95         SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
  96         // 50ms for the resonant antenna to settle.
  97         SpinDelay(50);
  98         // Now set up the SSC to get the ADC samples that are now streaming at us.
  99         FpgaSetupSsc();
 100         // start a 1.5ticks is 1us
 101         StartTicks();
 102 }
 103
 104 /**
 105  * Does the sample acquisition. If threshold is specified, the actual sampling
 106  * is not commenced until the threshold has been reached.
 107  * This method implements decimation and quantization in order to
 108  * be able to provide longer sample traces.
 109  * Uses the following global settings:
 110  * @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
 111  * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
 112  * @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
 113  * value that will be used is the average value of the three samples.
 114  * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
 115  * to -1 to ignore threshold.
 116  * @param silent - is true, now outputs are made. If false, dbprints the status
 117  * @return the number of bits occupied by the samples.
 118  */
 119 uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold, bool silent) {
 120         //bigbuf, to hold the aquired raw data signal
 121         uint8_t *dest = BigBuf_get_addr();
 122     uint16_t bufsize = BigBuf_max_traceLen();
 123
 124         //BigBuf_Clear_ext(false);        //creates issues with cmdread (marshmellow)
 125
 126         if(bits_per_sample < 1) bits_per_sample = 1;
 127         if(bits_per_sample > 8) bits_per_sample = 8;
 128
 129         if(decimation < 1) decimation = 1;
 130
 131         // Use a bit stream to handle the output
 132         BitstreamOut data = { dest , 0, 0};
 133         int sample_counter = 0;
 134         uint8_t sample = 0;
 135         //If we want to do averaging
 136         uint32_t sample_sum =0 ;
 137         uint32_t sample_total_numbers =0 ;
 138         uint32_t sample_total_saved =0 ;
 139
 140         while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
 141                 WDT_HIT();
 142                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
 143                         AT91C_BASE_SSC->SSC_THR = 0x00; //0x43;
 144                         LED_D_ON();
 145                 }
 146                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 147                         sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 148                         LED_D_OFF();
 149                         // threshold either high or low values 128 = center 0.  if trigger = 178
 150                         if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-trigger_threshold))) //
 151                                 continue;
 152
 153                         trigger_threshold = 0;
 154                         sample_total_numbers++;
 155
 156                         if(averaging)
 157                         {
 158                                 sample_sum += sample;
 159                         }
 160                         //Check decimation
 161                         if(decimation > 1)
 162                         {
 163                                 sample_counter++;
 164                                 if(sample_counter < decimation) continue;
 165                                 sample_counter = 0;
 166                         }
 167                         //Averaging
 168                         if(averaging && decimation > 1) {
 169                                 sample = sample_sum / decimation;
 170                                 sample_sum =0;
 171                         }
 172                         //Store the sample
 173                         sample_total_saved ++;
 174                         if(bits_per_sample == 8){
 175                                 dest[sample_total_saved-1] = sample;
 176                                 data.numbits = sample_total_saved << 3;//Get the return value correct
 177                                 if(sample_total_saved >= bufsize) break;
 178                         }
 179                         else{
 180                                 pushBit(&data, sample & 0x80);
 181                                 if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
 182                                 if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
 183                                 if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
 184                                 if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
 185                                 if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
 186                                 if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
 187                                 //Not needed, 8bps is covered above
 188                                 //if(bits_per_sample > 7)       pushBit(&data, sample & 0x01);
 189                                 if((data.numbits >> 3) +1  >= bufsize) break;
 190                         }
 191                 }
 192         }
 193
 194         if(!silent)
 195         {
 196                 Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
 197                 Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
 198                                         dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
 199         }
 200         return data.numbits;
 201 }
 202 /**
 203  * @brief Does sample acquisition, ignoring the config values set in the sample_config.
 204  * This method is typically used by tag-specific readers who just wants to read the samples
 205  * the normal way
 206  * @param trigger_threshold
 207  * @param silent
 208  * @return number of bits sampled
 209  */
 210 uint32_t DoAcquisition_default(int trigger_threshold, bool silent) {
 211         return DoAcquisition(1,8,0,trigger_threshold,silent);
 212 }
 213 uint32_t DoAcquisition_config( bool silent) {
 214         return DoAcquisition(config.decimation
 215                                   ,config.bits_per_sample
 216                                   ,config.averaging
 217                                   ,config.trigger_threshold
 218                                   ,silent);
 219 }
 220
 221 uint32_t ReadLF(bool activeField, bool silent) {
 222         if (!silent)
 223                 printConfig();
 224         LFSetupFPGAForADC(config.divisor, activeField);
 225         return DoAcquisition_config(silent);
 226 }
 227
 228 /**
 229 * Initializes the FPGA for reader-mode (field on), and acquires the samples.
 230 * @return number of bits sampled
 231 **/
 232 uint32_t SampleLF(bool printCfg) {
 233         BigBuf_Clear_ext(false);
 234         uint32_t ret = ReadLF(true, printCfg);
 235         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 236         return ret;
 237 }
 238 /**
 239 * Initializes the FPGA for snoop-mode (field off), and acquires the samples.
 240 * @return number of bits sampled
 241 **/
 242 uint32_t SnoopLF() {
 243         BigBuf_Clear_ext(false);
 244         uint32_t ret = ReadLF(false, true);
 245         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 246         return ret;
 247 }
 248
 249 /**
 250 * acquisition of T55x7 LF signal. Similart to other LF, but adjusted with @marshmellows thresholds
 251 * the data is collected in BigBuf.
 252 **/
 253 void doT55x7Acquisition(size_t sample_size) {
 254
 255         #define T55xx_READ_UPPER_THRESHOLD 128+40  // 60 grph
 256         #define T55xx_READ_LOWER_THRESHOLD 128-40  // -60 grph
 257         #define T55xx_READ_TOL   2
 258
 259         uint8_t *dest = BigBuf_get_addr();
 260         uint16_t bufsize = BigBuf_max_traceLen();
 261
 262         if ( bufsize > sample_size )
 263                 bufsize = sample_size;
 264
 265         uint8_t curSample = 0, lastSample = 0;
 266         uint16_t i = 0, skipCnt = 0;
 267         bool startFound = false;
 268         bool highFound = false;
 269         bool lowFound = false;
 270
 271         while(!BUTTON_PRESS() && !usb_poll_validate_length() && skipCnt < 1000 && (i < bufsize) ) {
 272                 WDT_HIT();
 273                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
 274                         AT91C_BASE_SSC->SSC_THR = 0x43; //43
 275                         LED_D_ON();
 276                 }
 277                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 278                         curSample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 279                         LED_D_OFF();
 280
 281                         // skip until the first high sample above threshold
 282                         if (!startFound && curSample > T55xx_READ_UPPER_THRESHOLD) {
 283                                 //if (curSample > lastSample)
 284                                 //      lastSample = curSample;
 285                                 highFound = true;
 286                         } else if (!highFound) {
 287                                 skipCnt++;
 288                                 continue;
 289                         }
 290                         // skip until the first low sample below threshold
 291                         if (!startFound && curSample < T55xx_READ_LOWER_THRESHOLD) {
 292                                 //if (curSample > lastSample)
 293                                 lastSample = curSample;
 294                                 lowFound = true;
 295                         } else if (!lowFound) {
 296                                 skipCnt++;
 297                                 continue;
 298                         }
 299
 300                         // skip until first high samples begin to change
 301                         if (startFound || curSample > T55xx_READ_LOWER_THRESHOLD + T55xx_READ_TOL){
 302                                 // if just found start - recover last sample
 303                                 if (!startFound) {
 304                                         dest[i++] = lastSample;
 305                                         startFound = true;
 306                                 }
 307                                 // collect samples
 308                                 dest[i++] = curSample;
 309                         }
 310                 }
 311         }
 312 }
 313