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         // Give it a bit of time 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
  95         // start a 1.5ticks is 1us
  96         StartTicks();
  97 }
  98
  99 /**
 100  * Does the sample acquisition. If threshold is specified, the actual sampling
 101  * is not commenced until the threshold has been reached.
 102  * This method implements decimation and quantization in order to
 103  * be able to provide longer sample traces.
 104  * Uses the following global settings:
 105  * @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
 106  * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
 107  * @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
 108  * value that will be used is the average value of the three samples.
 109  * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
 110  * to -1 to ignore threshold.
 111  * @param silent - is true, now outputs are made. If false, dbprints the status
 112  * @return the number of bits occupied by the samples.
 113  */
 114 uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold,bool silent) {
 115         //bigbuf, to hold the aquired raw data signal
 116         uint8_t *dest = BigBuf_get_addr();
 117     uint16_t bufsize = BigBuf_max_traceLen();
 118
 119         //BigBuf_Clear_ext(false);        //creates issues with cmdread (marshmellow)
 120
 121         if(bits_per_sample < 1) bits_per_sample = 1;
 122         if(bits_per_sample > 8) bits_per_sample = 8;
 123
 124         if(decimation < 1) decimation = 1;
 125
 126         // Use a bit stream to handle the output
 127         BitstreamOut data = { dest , 0, 0};
 128         int sample_counter = 0;
 129         uint8_t sample = 0;
 130         //If we want to do averaging
 131         uint32_t sample_sum =0 ;
 132         uint32_t sample_total_numbers =0 ;
 133         uint32_t sample_total_saved =0 ;
 134
 135         while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
 136                 WDT_HIT();
 137                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
 138                         AT91C_BASE_SSC->SSC_THR = 0x43;
 139                         LED_D_ON();
 140                 }
 141                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 142                         sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 143                         LED_D_OFF();
 144                         // threshold either high or low values 128 = center 0.  if trigger = 178
 145                         if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-trigger_threshold))) //
 146                                 continue;
 147
 148                         trigger_threshold = 0;
 149                         sample_total_numbers++;
 150
 151                         if(averaging)
 152                         {
 153                                 sample_sum += sample;
 154                         }
 155                         //Check decimation
 156                         if(decimation > 1)
 157                         {
 158                                 sample_counter++;
 159                                 if(sample_counter < decimation) continue;
 160                                 sample_counter = 0;
 161                         }
 162                         //Averaging
 163                         if(averaging && decimation > 1) {
 164                                 sample = sample_sum / decimation;
 165                                 sample_sum =0;
 166                         }
 167                         //Store the sample
 168                         sample_total_saved ++;
 169                         if(bits_per_sample == 8){
 170                                 dest[sample_total_saved-1] = sample;
 171                                 data.numbits = sample_total_saved << 3;//Get the return value correct
 172                                 if(sample_total_saved >= bufsize) break;
 173                         }
 174                         else{
 175                                 pushBit(&data, sample & 0x80);
 176                                 if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
 177                                 if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
 178                                 if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
 179                                 if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
 180                                 if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
 181                                 if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
 182                                 //Not needed, 8bps is covered above
 183                                 //if(bits_per_sample > 7)       pushBit(&data, sample & 0x01);
 184                                 if((data.numbits >> 3) +1  >= bufsize) break;
 185                         }
 186                 }
 187         }
 188
 189         if(!silent)
 190         {
 191                 Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
 192                 Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
 193                                         dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
 194         }
 195         return data.numbits;
 196 }
 197 /**
 198  * @brief Does sample acquisition, ignoring the config values set in the sample_config.
 199  * This method is typically used by tag-specific readers who just wants to read the samples
 200  * the normal way
 201  * @param trigger_threshold
 202  * @param silent
 203  * @return number of bits sampled
 204  */
 205 uint32_t DoAcquisition_default(int trigger_threshold, bool silent) {
 206         return DoAcquisition(1,8,0,trigger_threshold,silent);
 207 }
 208 uint32_t DoAcquisition_config( bool silent) {
 209         return DoAcquisition(config.decimation
 210                                   ,config.bits_per_sample
 211                                   ,config.averaging
 212                                   ,config.trigger_threshold
 213                                   ,silent);
 214 }
 215
 216 uint32_t ReadLF(bool activeField, bool silent) {
 217         if (!silent)
 218                 printConfig();
 219         LFSetupFPGAForADC(config.divisor, activeField);
 220         return DoAcquisition_config(silent);
 221 }
 222
 223 /**
 224 * Initializes the FPGA for reader-mode (field on), and acquires the samples.
 225 * @return number of bits sampled
 226 **/
 227 uint32_t SampleLF(bool printCfg) {
 228         return ReadLF(true, printCfg);
 229 }
 230 /**
 231 * Initializes the FPGA for snoop-mode (field off), and acquires the samples.
 232 * @return number of bits sampled
 233 **/
 234 uint32_t SnoopLF() {
 235         return ReadLF(false, true);
 236 }
 237
 238 /**
 239 * acquisition of T55x7 LF signal. Similart to other LF, but adjusted with @marshmellows thresholds
 240 * the data is collected in BigBuf.
 241 **/
 242 void doT55x7Acquisition(size_t sample_size) {
 243
 244         #define T55xx_READ_UPPER_THRESHOLD 128+40  // 60 grph
 245         #define T55xx_READ_LOWER_THRESHOLD 128-40  // -60 grph
 246         #define T55xx_READ_TOL   2
 247
 248         uint8_t *dest = BigBuf_get_addr();
 249         uint16_t bufsize = BigBuf_max_traceLen();
 250
 251         if ( bufsize > sample_size )
 252                 bufsize = sample_size;
 253
 254         uint8_t curSample = 0, lastSample = 0;
 255         uint16_t i = 0, skipCnt = 0;
 256         bool startFound = false;
 257         bool highFound = false;
 258         bool lowFound = false;
 259
 260         while(!BUTTON_PRESS() && !usb_poll_validate_length() && skipCnt < 1000 && (i < bufsize) ) {
 261                 WDT_HIT();
 262                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
 263                         AT91C_BASE_SSC->SSC_THR = 0x43;
 264                         LED_D_ON();
 265                 }
 266                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 267                         curSample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 268                         LED_D_OFF();
 269
 270                         // skip until the first high sample above threshold
 271                         if (!startFound && curSample > T55xx_READ_UPPER_THRESHOLD) {
 272                                 //if (curSample > lastSample)
 273                                 //      lastSample = curSample;
 274                                 highFound = true;
 275                         } else if (!highFound) {
 276                                 skipCnt++;
 277                                 continue;
 278                         }
 279                         // skip until the first Low sample below threshold
 280                         if (!startFound && curSample < T55xx_READ_LOWER_THRESHOLD) {
 281                                 //if (curSample > lastSample)
 282                                 lastSample = curSample;
 283                                 lowFound = true;
 284                         } else if (!lowFound) {
 285                                 skipCnt++;
 286                                 continue;
 287                         }
 288
 289
 290                         // skip until first high samples begin to change
 291                         if (startFound || curSample > T55xx_READ_LOWER_THRESHOLD + T55xx_READ_TOL){
 292                                 // if just found start - recover last sample
 293                                 if (!startFound) {
 294                                         dest[i++] = lastSample;
 295                                         startFound = true;
 296                                 }
 297                                 // collect samples
 298                                 dest[i++] = curSample;
 299                         }
 300                 }
 301         }
 302 }
 303