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