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