git.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 "proxmark3.h"
  10 #include "apps.h"
  11 #include "util.h"
  12 #include "string.h"
  13 #include "lfsampling.h"
  14 #include "usb_cdc.h"    // for usb_poll_validate_length
  15 #include "fpgaloader.h"
  16
  17 sample_config config = { 1, 8, 1, 95, 0, 0 } ;
  18
  19 void printConfig()
  20 {
  21         Dbprintf("LF Sampling config: ");
  22         Dbprintf("  [q] divisor:           %d ", config.divisor);
  23         Dbprintf("  [b] bps:               %d ", config.bits_per_sample);
  24         Dbprintf("  [d] decimation:        %d ", config.decimation);
  25         Dbprintf("  [a] averaging:         %d ", config.averaging);
  26         Dbprintf("  [t] trigger threshold: %d ", config.trigger_threshold);
  27         Dbprintf("  [s] samples to skip:   %d ", config.samples_to_skip);
  28 }
  29
  30
  31 /**
  32  * Called from the USB-handler to set the sampling configuration
  33  * The sampling config is used for std reading and snooping.
  34  *
  35  * Other functions may read samples and ignore the sampling config,
  36  * such as functions to read the UID from a prox tag or similar.
  37  *
  38  * Values set to '0' implies no change (except for averaging, threshold, samples_to_skip)
  39  * @brief setSamplingConfig
  40  * @param sc
  41  */
  42 void setSamplingConfig(sample_config *sc)
  43 {
  44         if(sc->divisor != 0) config.divisor = sc->divisor;
  45         if(sc->bits_per_sample!= 0) config.bits_per_sample= sc->bits_per_sample;
  46         if(sc->decimation!= 0) config.decimation= sc->decimation;
  47         if(sc->trigger_threshold != -1) config.trigger_threshold= sc->trigger_threshold;
  48         if(sc->samples_to_skip != -1) config.samples_to_skip = sc->samples_to_skip;
  49
  50         config.averaging= sc->averaging;
  51         if(config.bits_per_sample > 8)  config.bits_per_sample = 8;
  52         if(config.decimation < 1)       config.decimation = 1;
  53
  54         printConfig();
  55 }
  56
  57 sample_config* getSamplingConfig()
  58 {
  59         return &config;
  60 }
  61
  62 typedef struct {
  63         uint8_t * buffer;
  64         uint32_t numbits;
  65         uint32_t position;
  66 } BitstreamOut;
  67
  68 /**
  69  * @brief Pushes bit onto the stream
  70  * @param stream
  71  * @param bit
  72  */
  73 void pushBit( BitstreamOut* stream, uint8_t bit)
  74 {
  75         int bytepos = stream->position >> 3; // divide by 8
  76         int bitpos = stream->position & 7;
  77         *(stream->buffer+bytepos) |= (bit > 0) <<  (7 - bitpos);
  78         stream->position++;
  79         stream->numbits++;
  80 }
  81
  82 /**
  83 * Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
  84 * if not already loaded, sets divisor and starts up the antenna.
  85 * @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
  86 *                                  0 or 95 ==> 125 KHz
  87 *
  88 **/
  89 void LFSetupFPGAForADC(int divisor, bool lf_field)
  90 {
  91         FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
  92         if ( (divisor == 1) || (divisor < 0) || (divisor > 255) )
  93                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
  94         else if (divisor == 0)
  95                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
  96         else
  97                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
  98
  99         FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
 100
 101         // Connect the A/D to the peak-detected low-frequency path.
 102         SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
 103         // Give it a bit of time for the resonant antenna to settle.
 104         SpinDelay(50);
 105         // Now set up the SSC to get the ADC samples that are now streaming at us.
 106         FpgaSetupSsc(FPGA_MAJOR_MODE_LF_ADC);
 107 }
 108
 109 /**
 110  * Does the sample acquisition. If threshold is specified, the actual sampling
 111  * is not commenced until the threshold has been reached.
 112  * This method implements decimation and quantization in order to
 113  * be able to provide longer sample traces.
 114  * Uses the following global settings:
 115  * @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
 116  * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
 117  * @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
 118  * value that will be used is the average value of the three samples.
 119  * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
 120  * to -1 to ignore threshold.
 121  * @param silent - is true, now outputs are made. If false, dbprints the status
 122  * @return the number of bits occupied by the samples.
 123  */
 124 uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold, bool silent, int bufsize, int cancel_after, int samples_to_skip)
 125 {
 126         //.
 127         uint8_t *dest = BigBuf_get_addr();
 128         bufsize = (bufsize > 0 && bufsize < BigBuf_max_traceLen()) ? bufsize : BigBuf_max_traceLen();
 129
 130         //memset(dest, 0, bufsize); //creates issues with cmdread (marshmellow)
 131
 132         if(bits_per_sample < 1) bits_per_sample = 1;
 133         if(bits_per_sample > 8) bits_per_sample = 8;
 134
 135         if(decimation < 1) decimation = 1;
 136
 137         // Use a bit stream to handle the output
 138         BitstreamOut data = { dest , 0, 0};
 139         int sample_counter = 0;
 140         uint8_t sample = 0;
 141         //If we want to do averaging
 142         uint32_t sample_sum =0 ;
 143         uint32_t sample_total_numbers =0 ;
 144         uint32_t sample_total_saved =0 ;
 145         uint32_t cancel_counter = 0;
 146         uint32_t samples_skipped = 0;
 147
 148         while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
 149                 WDT_HIT();
 150                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
 151                         AT91C_BASE_SSC->SSC_THR = 0x43;
 152                         LED_D_ON();
 153                 }
 154                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 155                         sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 156                         LED_D_OFF();
 157                         // threshold either high or low values 128 = center 0.  if trigger = 178
 158                         if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-trigger_threshold))) { //
 159                                 if (cancel_after > 0) {
 160                                         cancel_counter++;
 161                                         if (cancel_after == cancel_counter) break;
 162                                 }
 163                                 continue;
 164                         }
 165                         trigger_threshold = 0;
 166                         if (samples_to_skip > samples_skipped) {
 167                                 samples_skipped++;
 168                                 continue;
 169                         }
 170                         sample_total_numbers++;
 171
 172                         if(averaging)
 173                         {
 174                                 sample_sum += sample;
 175                         }
 176                         //Check decimation
 177                         if(decimation > 1)
 178                         {
 179                                 sample_counter++;
 180                                 if(sample_counter < decimation) continue;
 181                                 sample_counter = 0;
 182                         }
 183                         //Averaging
 184                         if(averaging && decimation > 1) {
 185                                 sample = sample_sum / decimation;
 186                                 sample_sum =0;
 187                         }
 188                         //Store the sample
 189                         sample_total_saved ++;
 190                         if(bits_per_sample == 8){
 191                                 dest[sample_total_saved-1] = sample;
 192                                 data.numbits = sample_total_saved << 3;//Get the return value correct
 193                                 if(sample_total_saved >= bufsize) break;
 194                         }
 195                         else{
 196                                 pushBit(&data, sample & 0x80);
 197                                 if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
 198                                 if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
 199                                 if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
 200                                 if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
 201                                 if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
 202                                 if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
 203                                 //Not needed, 8bps is covered above
 204                                 //if(bits_per_sample > 7)       pushBit(&data, sample & 0x01);
 205                                 if((data.numbits >> 3) +1  >= bufsize) break;
 206                         }
 207                 }
 208         }
 209
 210         if(!silent)
 211         {
 212                 Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
 213                 Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
 214                                         dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
 215         }
 216         return data.numbits;
 217 }
 218 /**
 219  * @brief Does sample acquisition, ignoring the config values set in the sample_config.
 220  * This method is typically used by tag-specific readers who just wants to read the samples
 221  * the normal way
 222  * @param trigger_threshold
 223  * @param silent
 224  * @return number of bits sampled
 225  */
 226 uint32_t DoAcquisition_default(int trigger_threshold, bool silent)
 227 {
 228         return DoAcquisition(1,8,0,trigger_threshold,silent,0,0,0);
 229 }
 230 uint32_t DoAcquisition_config(bool silent, int sample_size)
 231 {
 232         return DoAcquisition(config.decimation
 233                                   ,config.bits_per_sample
 234                                   ,config.averaging
 235                                   ,config.trigger_threshold
 236                                   ,silent
 237                                   ,sample_size
 238                                   ,0
 239                                   ,config.samples_to_skip);
 240 }
 241
 242 uint32_t DoPartialAcquisition(int trigger_threshold, bool silent, int sample_size, int cancel_after) {
 243         return DoAcquisition(1,8,0,trigger_threshold,silent,sample_size,cancel_after,0);
 244 }
 245
 246 uint32_t ReadLF(bool activeField, bool silent, int sample_size)
 247 {
 248         if (!silent) printConfig();
 249         LFSetupFPGAForADC(config.divisor, activeField);
 250         // Now call the acquisition routine
 251         return DoAcquisition_config(silent, sample_size);
 252 }
 253
 254 /**
 255 * Initializes the FPGA for reader-mode (field on), and acquires the samples.
 256 * @return number of bits sampled
 257 **/
 258 uint32_t SampleLF(bool printCfg, int sample_size)
 259 {
 260         uint32_t ret = ReadLF(true, printCfg, sample_size);
 261         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 262         return ret;
 263 }
 264 /**
 265 * Initializes the FPGA for snoop-mode (field off), and acquires the samples.
 266 * @return number of bits sampled
 267 **/
 268
 269 uint32_t SnoopLF()
 270 {
 271         uint32_t ret = ReadLF(false, true, 0);
 272         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 273         return ret;
 274 }
 275
 276 /**
 277 * acquisition of Cotag LF signal. Similar to other LF,  since the Cotag has such long datarate RF/384
 278 * and is Manchester?,  we directly gather the manchester data into bigbuff
 279 **/
 280 #define COTAG_T1 384
 281 #define COTAG_T2 (COTAG_T1>>1)
 282 #define COTAG_ONE_THRESHOLD 128+30
 283 #define COTAG_ZERO_THRESHOLD 128-30
 284 #ifndef COTAG_BITS
 285 #define COTAG_BITS 264
 286 #endif
 287 void doCotagAcquisition(size_t sample_size) {
 288
 289         uint8_t *dest = BigBuf_get_addr();
 290         uint16_t bufsize = BigBuf_max_traceLen();
 291
 292         if ( bufsize > sample_size )
 293                 bufsize = sample_size;
 294
 295         dest[0] = 0;
 296         uint8_t sample = 0, firsthigh = 0, firstlow = 0;
 297         uint16_t i = 0;
 298
 299         while (!BUTTON_PRESS() && !usb_poll_validate_length() && (i < bufsize) ) {
 300                 WDT_HIT();
 301                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
 302                         AT91C_BASE_SSC->SSC_THR = 0x43;
 303                         LED_D_ON();
 304                 }
 305
 306                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 307                         sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 308                         LED_D_OFF();
 309
 310                         // find first peak
 311                         if ( !firsthigh ) {
 312                                 if (sample < COTAG_ONE_THRESHOLD)
 313                                         continue;
 314                                 firsthigh = 1;
 315                         }
 316                         if ( !firstlow ){
 317                                 if (sample > COTAG_ZERO_THRESHOLD )
 318                                         continue;
 319                                 firstlow = 1;
 320                         }
 321
 322                         ++i;
 323
 324                         if ( sample > COTAG_ONE_THRESHOLD)
 325                                 dest[i] = 255;
 326                         else if ( sample < COTAG_ZERO_THRESHOLD)
 327                                 dest[i] = 0;
 328                         else
 329                                 dest[i] = dest[i-1];
 330                 }
 331         }
 332 }
 333
 334 uint32_t doCotagAcquisitionManchester() {
 335
 336         uint8_t *dest = BigBuf_get_addr();
 337         uint16_t bufsize = BigBuf_max_traceLen();
 338
 339         if ( bufsize > COTAG_BITS )
 340                 bufsize = COTAG_BITS;
 341
 342         dest[0] = 0;
 343         uint8_t sample = 0, firsthigh = 0, firstlow = 0;
 344         uint16_t sample_counter = 0, period = 0;
 345         uint8_t curr = 0, prev = 0;
 346         uint16_t noise_counter = 0;
 347         while (!BUTTON_PRESS() && !usb_poll_validate_length() && (sample_counter < bufsize) && (noise_counter < (COTAG_T1<<1)) ) {
 348                 WDT_HIT();
 349                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
 350                         AT91C_BASE_SSC->SSC_THR = 0x43;
 351                         LED_D_ON();
 352                 }
 353
 354                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 355                         sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 356                         LED_D_OFF();
 357
 358                         // find first peak
 359                         if ( !firsthigh ) {
 360                                 if (sample < COTAG_ONE_THRESHOLD) {
 361                                         noise_counter++;
 362                                         continue;
 363                                 }
 364                                 noise_counter = 0;
 365                                 firsthigh = 1;
 366                         }
 367
 368                         if ( !firstlow ){
 369                                 if (sample > COTAG_ZERO_THRESHOLD ) {
 370                                         noise_counter++;
 371                                         continue;
 372                                 }
 373                                 noise_counter=0;
 374                                 firstlow = 1;
 375                         }
 376
 377                         // set sample 255, 0,  or previous
 378                         if ( sample > COTAG_ONE_THRESHOLD){
 379                                 prev = curr;
 380                                 curr = 1;
 381                         }
 382                         else if ( sample < COTAG_ZERO_THRESHOLD) {
 383                                 prev = curr;
 384                                 curr = 0;
 385                         }
 386                         else {
 387                                 curr = prev;
 388                         }
 389
 390                         // full T1 periods,
 391                         if ( period > 0 ) {
 392                                 --period;
 393                                 continue;
 394                         }
 395
 396                         dest[sample_counter] = curr;
 397                         ++sample_counter;
 398                         period = COTAG_T1;
 399                 }
 400         }
 401         return sample_counter;
 402 }