git.zerfleddert.de Git - proxmark3-svn/blob - armsrc/lfops.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 tag operations.
   7 // Tags supported here so far are Texas Instruments (TI), HID
   8 // Also routines for raw mode reading/simulating of LF waveform
   9 //-----------------------------------------------------------------------------
  10
  11 #include "proxmark3.h"
  12 #include "apps.h"
  13 #include "util.h"
  14 #include "hitag2.h"
  15 #include "crc16.h"
  16 #include "string.h"
  17 #include "lfdemod.h"
  18
  19
  20 /**
  21 * Does the sample acquisition. If threshold is specified, the actual sampling
  22 * is not commenced until the threshold has been reached.
  23 * @param trigger_threshold - the threshold
  24 * @param silent - is true, now outputs are made. If false, dbprints the status
  25 */
  26 void DoAcquisition125k_internal(int trigger_threshold,bool silent)
  27 {
  28     uint8_t *dest = (uint8_t *)BigBuf;
  29     int n = sizeof(BigBuf);
  30     int i;
  31
  32     memset(dest, 0, n);
  33     i = 0;
  34     for(;;) {
  35         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
  36             AT91C_BASE_SSC->SSC_THR = 0x43;
  37             LED_D_ON();
  38         }
  39         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
  40             dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
  41             LED_D_OFF();
  42             if (trigger_threshold != -1 && dest[i] < trigger_threshold)
  43                 continue;
  44             else
  45                 trigger_threshold = -1;
  46             if (++i >= n) break;
  47         }
  48     }
  49     if(!silent)
  50     {
  51         Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
  52                  dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
  53
  54     }
  55 }
  56 /**
  57 * Perform sample aquisition.
  58 */
  59 void DoAcquisition125k(int trigger_threshold)
  60 {
  61     DoAcquisition125k_internal(trigger_threshold, false);
  62 }
  63
  64 /**
  65 * Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
  66 * if not already loaded, sets divisor and starts up the antenna.
  67 * @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
  68 *                                  0 or 95 ==> 125 KHz
  69 *
  70 **/
  71 void LFSetupFPGAForADC(int divisor, bool lf_field)
  72 {
  73     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
  74     if ( (divisor == 1) || (divisor < 0) || (divisor > 255) )
  75         FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
  76     else if (divisor == 0)
  77         FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
  78     else
  79         FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
  80
  81     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
  82
  83     // Connect the A/D to the peak-detected low-frequency path.
  84     SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
  85     // Give it a bit of time for the resonant antenna to settle.
  86     SpinDelay(50);
  87     // Now set up the SSC to get the ADC samples that are now streaming at us.
  88     FpgaSetupSsc();
  89 }
  90 /**
  91 * Initializes the FPGA, and acquires the samples.
  92 **/
  93 void AcquireRawAdcSamples125k(int divisor)
  94 {
  95     LFSetupFPGAForADC(divisor, true);
  96     // Now call the acquisition routine
  97     DoAcquisition125k_internal(-1,false);
  98 }
  99 /**
 100 * Initializes the FPGA for snoop-mode, and acquires the samples.
 101 **/
 102
 103 void SnoopLFRawAdcSamples(int divisor, int trigger_threshold)
 104 {
 105     LFSetupFPGAForADC(divisor, false);
 106     DoAcquisition125k(trigger_threshold);
 107 }
 108
 109 void ModThenAcquireRawAdcSamples125k(int delay_off, int period_0, int period_1, uint8_t *command)
 110 {
 111
 112     /* Make sure the tag is reset */
 113     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 114     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 115     SpinDelay(2500);
 116
 117
 118     int divisor_used = 95; // 125 KHz
 119     // see if 'h' was specified
 120
 121     if (command[strlen((char *) command) - 1] == 'h')
 122         divisor_used = 88; // 134.8 KHz
 123
 124
 125     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor_used);
 126     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 127     // Give it a bit of time for the resonant antenna to settle.
 128     SpinDelay(50);
 129
 130     // And a little more time for the tag to fully power up
 131     SpinDelay(2000);
 132
 133     // Now set up the SSC to get the ADC samples that are now streaming at us.
 134     FpgaSetupSsc();
 135
 136     // now modulate the reader field
 137     while(*command != '\0' && *command != ' ') {
 138         FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 139         LED_D_OFF();
 140         SpinDelayUs(delay_off);
 141         FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor_used);
 142
 143         FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 144         LED_D_ON();
 145         if(*(command++) == '0')
 146             SpinDelayUs(period_0);
 147         else
 148             SpinDelayUs(period_1);
 149     }
 150     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 151     LED_D_OFF();
 152     SpinDelayUs(delay_off);
 153     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor_used);
 154
 155     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 156
 157     // now do the read
 158     DoAcquisition125k(-1);
 159 }
 160
 161 /* blank r/w tag data stream
 162 ...0000000000000000 01111111
 163 1010101010101010101010101010101010101010101010101010101010101010
 164 0011010010100001
 165 01111111
 166 101010101010101[0]000...
 167
 168 [5555fe852c5555555555555555fe0000]
 169 */
 170 void ReadTItag(void)
 171 {
 172     // some hardcoded initial params
 173     // when we read a TI tag we sample the zerocross line at 2Mhz
 174     // TI tags modulate a 1 as 16 cycles of 123.2Khz
 175     // TI tags modulate a 0 as 16 cycles of 134.2Khz
 176 #define FSAMPLE 2000000
 177 #define FREQLO 123200
 178 #define FREQHI 134200
 179
 180     signed char *dest = (signed char *)BigBuf;
 181     int n = sizeof(BigBuf);
 182
 183     // 128 bit shift register [shift3:shift2:shift1:shift0]
 184     uint32_t shift3 = 0, shift2 = 0, shift1 = 0, shift0 = 0;
 185
 186     int i, cycles=0, samples=0;
 187     // how many sample points fit in 16 cycles of each frequency
 188     uint32_t sampleslo = (FSAMPLE<<4)/FREQLO, sampleshi = (FSAMPLE<<4)/FREQHI;
 189     // when to tell if we're close enough to one freq or another
 190     uint32_t threshold = (sampleslo - sampleshi + 1)>>1;
 191
 192     // TI tags charge at 134.2Khz
 193     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 194     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
 195
 196     // Place FPGA in passthrough mode, in this mode the CROSS_LO line
 197     // connects to SSP_DIN and the SSP_DOUT logic level controls
 198     // whether we're modulating the antenna (high)
 199     // or listening to the antenna (low)
 200     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
 201
 202     // get TI tag data into the buffer
 203     AcquireTiType();
 204
 205     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 206
 207     for (i=0; i<n-1; i++) {
 208         // count cycles by looking for lo to hi zero crossings
 209         if ( (dest[i]<0) && (dest[i+1]>0) ) {
 210             cycles++;
 211             // after 16 cycles, measure the frequency
 212             if (cycles>15) {
 213                 cycles=0;
 214                 samples=i-samples; // number of samples in these 16 cycles
 215
 216                 // TI bits are coming to us lsb first so shift them
 217                 // right through our 128 bit right shift register
 218                 shift0 = (shift0>>1) | (shift1 << 31);
 219                 shift1 = (shift1>>1) | (shift2 << 31);
 220                 shift2 = (shift2>>1) | (shift3 << 31);
 221                 shift3 >>= 1;
 222
 223                 // check if the cycles fall close to the number
 224                 // expected for either the low or high frequency
 225                 if ( (samples>(sampleslo-threshold)) && (samples<(sampleslo+threshold)) ) {
 226                     // low frequency represents a 1
 227                     shift3 |= (1<<31);
 228                 } else if ( (samples>(sampleshi-threshold)) && (samples<(sampleshi+threshold)) ) {
 229                     // high frequency represents a 0
 230                 } else {
 231                     // probably detected a gay waveform or noise
 232                     // use this as gaydar or discard shift register and start again
 233                     shift3 = shift2 = shift1 = shift0 = 0;
 234                 }
 235                 samples = i;
 236
 237                 // for each bit we receive, test if we've detected a valid tag
 238
 239                 // if we see 17 zeroes followed by 6 ones, we might have a tag
 240                 // remember the bits are backwards
 241                 if ( ((shift0 & 0x7fffff) == 0x7e0000) ) {
 242                     // if start and end bytes match, we have a tag so break out of the loop
 243                     if ( ((shift0>>16)&0xff) == ((shift3>>8)&0xff) ) {
 244                         cycles = 0xF0B; //use this as a flag (ugly but whatever)
 245                         break;
 246                     }
 247                 }
 248             }
 249         }
 250     }
 251
 252     // if flag is set we have a tag
 253     if (cycles!=0xF0B) {
 254         DbpString("Info: No valid tag detected.");
 255     } else {
 256         // put 64 bit data into shift1 and shift0
 257         shift0 = (shift0>>24) | (shift1 << 8);
 258         shift1 = (shift1>>24) | (shift2 << 8);
 259
 260         // align 16 bit crc into lower half of shift2
 261         shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;
 262
 263         // if r/w tag, check ident match
 264         if ( shift3&(1<<15) ) {
 265             DbpString("Info: TI tag is rewriteable");
 266             // only 15 bits compare, last bit of ident is not valid
 267             if ( ((shift3>>16)^shift0)&0x7fff ) {
 268                 DbpString("Error: Ident mismatch!");
 269             } else {
 270                 DbpString("Info: TI tag ident is valid");
 271             }
 272         } else {
 273             DbpString("Info: TI tag is readonly");
 274         }
 275
 276         // WARNING the order of the bytes in which we calc crc below needs checking
 277         // i'm 99% sure the crc algorithm is correct, but it may need to eat the
 278         // bytes in reverse or something
 279         // calculate CRC
 280         uint32_t crc=0;
 281
 282         crc = update_crc16(crc, (shift0)&0xff);
 283         crc = update_crc16(crc, (shift0>>8)&0xff);
 284         crc = update_crc16(crc, (shift0>>16)&0xff);
 285         crc = update_crc16(crc, (shift0>>24)&0xff);
 286         crc = update_crc16(crc, (shift1)&0xff);
 287         crc = update_crc16(crc, (shift1>>8)&0xff);
 288         crc = update_crc16(crc, (shift1>>16)&0xff);
 289         crc = update_crc16(crc, (shift1>>24)&0xff);
 290
 291         Dbprintf("Info: Tag data: %x%08x, crc=%x",
 292                  (unsigned int)shift1, (unsigned int)shift0, (unsigned int)shift2 & 0xFFFF);
 293         if (crc != (shift2&0xffff)) {
 294             Dbprintf("Error: CRC mismatch, expected %x", (unsigned int)crc);
 295         } else {
 296             DbpString("Info: CRC is good");
 297         }
 298     }
 299 }
 300
 301 void WriteTIbyte(uint8_t b)
 302 {
 303     int i = 0;
 304
 305     // modulate 8 bits out to the antenna
 306     for (i=0; i<8; i++)
 307     {
 308         if (b&(1<<i)) {
 309             // stop modulating antenna
 310             LOW(GPIO_SSC_DOUT);
 311             SpinDelayUs(1000);
 312             // modulate antenna
 313             HIGH(GPIO_SSC_DOUT);
 314             SpinDelayUs(1000);
 315         } else {
 316             // stop modulating antenna
 317             LOW(GPIO_SSC_DOUT);
 318             SpinDelayUs(300);
 319             // modulate antenna
 320             HIGH(GPIO_SSC_DOUT);
 321             SpinDelayUs(1700);
 322         }
 323     }
 324 }
 325
 326 void AcquireTiType(void)
 327 {
 328     int i, j, n;
 329     // tag transmission is <20ms, sampling at 2M gives us 40K samples max
 330     // each sample is 1 bit stuffed into a uint32_t so we need 1250 uint32_t
 331 #define TIBUFLEN 1250
 332
 333     // clear buffer
 334     memset(BigBuf,0,sizeof(BigBuf));
 335
 336     // Set up the synchronous serial port
 337     AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DIN;
 338     AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN;
 339
 340     // steal this pin from the SSP and use it to control the modulation
 341     AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
 342     AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
 343
 344     AT91C_BASE_SSC->SSC_CR = AT91C_SSC_SWRST;
 345     AT91C_BASE_SSC->SSC_CR = AT91C_SSC_RXEN | AT91C_SSC_TXEN;
 346
 347     // Sample at 2 Mbit/s, so TI tags are 16.2 vs. 14.9 clocks long
 348     // 48/2 = 24 MHz clock must be divided by 12
 349     AT91C_BASE_SSC->SSC_CMR = 12;
 350
 351     AT91C_BASE_SSC->SSC_RCMR = SSC_CLOCK_MODE_SELECT(0);
 352     AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(32) | AT91C_SSC_MSBF;
 353     AT91C_BASE_SSC->SSC_TCMR = 0;
 354     AT91C_BASE_SSC->SSC_TFMR = 0;
 355
 356     LED_D_ON();
 357
 358     // modulate antenna
 359     HIGH(GPIO_SSC_DOUT);
 360
 361     // Charge TI tag for 50ms.
 362     SpinDelay(50);
 363
 364     // stop modulating antenna and listen
 365     LOW(GPIO_SSC_DOUT);
 366
 367     LED_D_OFF();
 368
 369     i = 0;
 370     for(;;) {
 371         if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
 372             BigBuf[i] = AT91C_BASE_SSC->SSC_RHR;        // store 32 bit values in buffer
 373             i++; if(i >= TIBUFLEN) break;
 374         }
 375         WDT_HIT();
 376     }
 377
 378     // return stolen pin to SSP
 379     AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DOUT;
 380     AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN | GPIO_SSC_DOUT;
 381
 382     char *dest = (char *)BigBuf;
 383     n = TIBUFLEN*32;
 384     // unpack buffer
 385     for (i=TIBUFLEN-1; i>=0; i--) {
 386         for (j=0; j<32; j++) {
 387             if(BigBuf[i] & (1 << j)) {
 388                 dest[--n] = 1;
 389             } else {
 390                 dest[--n] = -1;
 391             }
 392         }
 393     }
 394 }
 395
 396 // arguments: 64bit data split into 32bit idhi:idlo and optional 16bit crc
 397 // if crc provided, it will be written with the data verbatim (even if bogus)
 398 // if not provided a valid crc will be computed from the data and written.
 399 void WriteTItag(uint32_t idhi, uint32_t idlo, uint16_t crc)
 400 {
 401     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 402     if(crc == 0) {
 403         crc = update_crc16(crc, (idlo)&0xff);
 404         crc = update_crc16(crc, (idlo>>8)&0xff);
 405         crc = update_crc16(crc, (idlo>>16)&0xff);
 406         crc = update_crc16(crc, (idlo>>24)&0xff);
 407         crc = update_crc16(crc, (idhi)&0xff);
 408         crc = update_crc16(crc, (idhi>>8)&0xff);
 409         crc = update_crc16(crc, (idhi>>16)&0xff);
 410         crc = update_crc16(crc, (idhi>>24)&0xff);
 411     }
 412     Dbprintf("Writing to tag: %x%08x, crc=%x",
 413              (unsigned int) idhi, (unsigned int) idlo, crc);
 414
 415     // TI tags charge at 134.2Khz
 416     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
 417     // Place FPGA in passthrough mode, in this mode the CROSS_LO line
 418     // connects to SSP_DIN and the SSP_DOUT logic level controls
 419     // whether we're modulating the antenna (high)
 420     // or listening to the antenna (low)
 421     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
 422     LED_A_ON();
 423
 424     // steal this pin from the SSP and use it to control the modulation
 425     AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
 426     AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
 427
 428     // writing algorithm:
 429     // a high bit consists of a field off for 1ms and field on for 1ms
 430     // a low bit consists of a field off for 0.3ms and field on for 1.7ms
 431     // initiate a charge time of 50ms (field on) then immediately start writing bits
 432     // start by writing 0xBB (keyword) and 0xEB (password)
 433     // then write 80 bits of data (or 64 bit data + 16 bit crc if you prefer)
 434     // finally end with 0x0300 (write frame)
 435     // all data is sent lsb firts
 436     // finish with 15ms programming time
 437
 438     // modulate antenna
 439     HIGH(GPIO_SSC_DOUT);
 440     SpinDelay(50);      // charge time
 441
 442     WriteTIbyte(0xbb); // keyword
 443     WriteTIbyte(0xeb); // password
 444     WriteTIbyte( (idlo    )&0xff );
 445     WriteTIbyte( (idlo>>8 )&0xff );
 446     WriteTIbyte( (idlo>>16)&0xff );
 447     WriteTIbyte( (idlo>>24)&0xff );
 448     WriteTIbyte( (idhi    )&0xff );
 449     WriteTIbyte( (idhi>>8 )&0xff );
 450     WriteTIbyte( (idhi>>16)&0xff );
 451     WriteTIbyte( (idhi>>24)&0xff ); // data hi to lo
 452     WriteTIbyte( (crc     )&0xff ); // crc lo
 453     WriteTIbyte( (crc>>8  )&0xff ); // crc hi
 454     WriteTIbyte(0x00); // write frame lo
 455     WriteTIbyte(0x03); // write frame hi
 456     HIGH(GPIO_SSC_DOUT);
 457     SpinDelay(50);      // programming time
 458
 459     LED_A_OFF();
 460
 461     // get TI tag data into the buffer
 462     AcquireTiType();
 463
 464     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 465     DbpString("Now use tiread to check");
 466 }
 467
 468 void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
 469 {
 470     int i;
 471     uint8_t *tab = (uint8_t *)BigBuf;
 472
 473     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 474     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT);
 475
 476     AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT | GPIO_SSC_CLK;
 477
 478     AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
 479     AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_CLK;
 480
 481 #define SHORT_COIL()    LOW(GPIO_SSC_DOUT)
 482 #define OPEN_COIL()             HIGH(GPIO_SSC_DOUT)
 483
 484     i = 0;
 485     for(;;) {
 486         while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)) {
 487             if(BUTTON_PRESS()) {
 488                 DbpString("Stopped");
 489                 return;
 490             }
 491             WDT_HIT();
 492         }
 493
 494         if (ledcontrol)
 495             LED_D_ON();
 496
 497         if(tab[i])
 498             OPEN_COIL();
 499         else
 500             SHORT_COIL();
 501
 502         if (ledcontrol)
 503             LED_D_OFF();
 504
 505         while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK) {
 506             if(BUTTON_PRESS()) {
 507                 DbpString("Stopped");
 508                 return;
 509             }
 510             WDT_HIT();
 511         }
 512
 513         i++;
 514         if(i == period) {
 515             i = 0;
 516             if (gap) {
 517                 SHORT_COIL();
 518                 SpinDelayUs(gap);
 519             }
 520         }
 521     }
 522 }
 523
 524 #define DEBUG_FRAME_CONTENTS 1
 525 void SimulateTagLowFrequencyBidir(int divisor, int t0)
 526 {
 527 }
 528
 529 // compose fc/8 fc/10 waveform
 530 static void fc(int c, int *n) {
 531     uint8_t *dest = (uint8_t *)BigBuf;
 532     int idx;
 533
 534     // for when we want an fc8 pattern every 4 logical bits
 535     if(c==0) {
 536         dest[((*n)++)]=1;
 537         dest[((*n)++)]=1;
 538         dest[((*n)++)]=0;
 539         dest[((*n)++)]=0;
 540         dest[((*n)++)]=0;
 541         dest[((*n)++)]=0;
 542         dest[((*n)++)]=0;
 543         dest[((*n)++)]=0;
 544     }
 545     //  an fc/8  encoded bit is a bit pattern of  11000000  x6 = 48 samples
 546     if(c==8) {
 547         for (idx=0; idx<6; idx++) {
 548             dest[((*n)++)]=1;
 549             dest[((*n)++)]=1;
 550             dest[((*n)++)]=0;
 551             dest[((*n)++)]=0;
 552             dest[((*n)++)]=0;
 553             dest[((*n)++)]=0;
 554             dest[((*n)++)]=0;
 555             dest[((*n)++)]=0;
 556         }
 557     }
 558
 559     //  an fc/10 encoded bit is a bit pattern of 1110000000 x5 = 50 samples
 560     if(c==10) {
 561         for (idx=0; idx<5; idx++) {
 562             dest[((*n)++)]=1;
 563             dest[((*n)++)]=1;
 564             dest[((*n)++)]=1;
 565             dest[((*n)++)]=0;
 566             dest[((*n)++)]=0;
 567             dest[((*n)++)]=0;
 568             dest[((*n)++)]=0;
 569             dest[((*n)++)]=0;
 570             dest[((*n)++)]=0;
 571             dest[((*n)++)]=0;
 572         }
 573     }
 574 }
 575
 576 // prepare a waveform pattern in the buffer based on the ID given then
 577 // simulate a HID tag until the button is pressed
 578 void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
 579 {
 580     int n=0, i=0;
 581     /*
 582      HID tag bitstream format
 583      The tag contains a 44bit unique code. This is sent out MSB first in sets of 4 bits
 584      A 1 bit is represented as 6 fc8 and 5 fc10 patterns
 585      A 0 bit is represented as 5 fc10 and 6 fc8 patterns
 586      A fc8 is inserted before every 4 bits
 587      A special start of frame pattern is used consisting a0b0 where a and b are neither 0
 588      nor 1 bits, they are special patterns (a = set of 12 fc8 and b = set of 10 fc10)
 589     */
 590
 591     if (hi>0xFFF) {
 592         DbpString("Tags can only have 44 bits.");
 593         return;
 594     }
 595     fc(0,&n);
 596     // special start of frame marker containing invalid bit sequences
 597     fc(8,  &n); fc(8,  &n);     // invalid
 598     fc(8,  &n); fc(10, &n); // logical 0
 599     fc(10, &n); fc(10, &n); // invalid
 600     fc(8,  &n); fc(10, &n); // logical 0
 601
 602     WDT_HIT();
 603     // manchester encode bits 43 to 32
 604     for (i=11; i>=0; i--) {
 605         if ((i%4)==3) fc(0,&n);
 606         if ((hi>>i)&1) {
 607             fc(10, &n); fc(8,  &n);             // low-high transition
 608         } else {
 609             fc(8,  &n); fc(10, &n);             // high-low transition
 610         }
 611     }
 612
 613     WDT_HIT();
 614     // manchester encode bits 31 to 0
 615     for (i=31; i>=0; i--) {
 616         if ((i%4)==3) fc(0,&n);
 617         if ((lo>>i)&1) {
 618             fc(10, &n); fc(8,  &n);             // low-high transition
 619         } else {
 620             fc(8,  &n); fc(10, &n);             // high-low transition
 621         }
 622     }
 623
 624     if (ledcontrol)
 625         LED_A_ON();
 626
 627     SimulateTagLowFrequency(n, 0, ledcontrol);
 628
 629     if (ledcontrol)
 630         LED_A_OFF();
 631 }
 632
 633 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
 634 void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
 635 {
 636     uint8_t *dest = (uint8_t *)BigBuf;
 637
 638     size_t size=0; //, found=0;
 639     uint32_t hi2=0, hi=0, lo=0;
 640
 641     // Configure to go in 125Khz listen mode
 642     LFSetupFPGAForADC(95, true);
 643
 644     while(!BUTTON_PRESS()) {
 645
 646         WDT_HIT();
 647         if (ledcontrol) LED_A_ON();
 648
 649         DoAcquisition125k_internal(-1,true);
 650         size  = sizeof(BigBuf);
 651         if (size < 2000) continue;
 652         // FSK demodulator
 653
 654         int bitLen = HIDdemodFSK(dest,size,&hi2,&hi,&lo);
 655
 656         WDT_HIT();
 657
 658         if (bitLen>0 && lo>0){
 659             // final loop, go over previously decoded manchester data and decode into usable tag ID
 660             // 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0
 661             if (hi2 != 0){ //extra large HID tags
 662                 Dbprintf("TAG ID: %x%08x%08x (%d)",
 663                          (unsigned int) hi2, (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
 664             }else {  //standard HID tags <38 bits
 665                 //Dbprintf("TAG ID: %x%08x (%d)",(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF); //old print cmd
 666                 uint8_t bitlen = 0;
 667                 uint32_t fc = 0;
 668                 uint32_t cardnum = 0;
 669                 if (((hi>>5)&1)==1){//if bit 38 is set then < 37 bit format is used
 670                     uint32_t lo2=0;
 671                     lo2=(((hi & 31) << 12) | (lo>>20)); //get bits 21-37 to check for format len bit
 672                     uint8_t idx3 = 1;
 673                     while(lo2>1){ //find last bit set to 1 (format len bit)
 674                         lo2=lo2>>1;
 675                         idx3++;
 676                     }
 677                     bitlen =idx3+19;
 678                     fc =0;
 679                     cardnum=0;
 680                     if(bitlen==26){
 681                         cardnum = (lo>>1)&0xFFFF;
 682                         fc = (lo>>17)&0xFF;
 683                     }
 684                     if(bitlen==37){
 685                         cardnum = (lo>>1)&0x7FFFF;
 686                         fc = ((hi&0xF)<<12)|(lo>>20);
 687                     }
 688                     if(bitlen==34){
 689                         cardnum = (lo>>1)&0xFFFF;
 690                         fc= ((hi&1)<<15)|(lo>>17);
 691                     }
 692                     if(bitlen==35){
 693                         cardnum = (lo>>1)&0xFFFFF;
 694                         fc = ((hi&1)<<11)|(lo>>21);
 695                     }
 696                 }
 697                 else { //if bit 38 is not set then 37 bit format is used
 698                     bitlen= 37;
 699                     fc =0;
 700                     cardnum=0;
 701                     if(bitlen==37){
 702                         cardnum = (lo>>1)&0x7FFFF;
 703                         fc = ((hi&0xF)<<12)|(lo>>20);
 704                     }
 705                 }
 706                 //Dbprintf("TAG ID: %x%08x (%d)",
 707                 // (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
 708                 Dbprintf("TAG ID: %x%08x (%d) - Format Len: %dbit - FC: %d - Card: %d",
 709                          (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF,
 710                          (unsigned int) bitlen, (unsigned int) fc, (unsigned int) cardnum);
 711             }
 712             if (findone){
 713                 if (ledcontrol) LED_A_OFF();
 714                 return;
 715             }
 716             // reset
 717             hi2 = hi = lo = 0;
 718         }
 719         WDT_HIT();
 720     }
 721     DbpString("Stopped");
 722     if (ledcontrol) LED_A_OFF();
 723 }
 724
 725 void CmdEM410xdemod(int findone, int *high, int *low, int ledcontrol)
 726 {
 727     uint8_t *dest = (uint8_t *)BigBuf;
 728
 729     size_t size=0; //, found=0;
 730     uint32_t bitLen=0;
 731     int clk=0, invert=0, errCnt=0;
 732     uint64_t lo=0;
 733     // Configure to go in 125Khz listen mode
 734     LFSetupFPGAForADC(95, true);
 735
 736     while(!BUTTON_PRESS()) {
 737
 738         WDT_HIT();
 739         if (ledcontrol) LED_A_ON();
 740
 741         DoAcquisition125k_internal(-1,true);
 742         size  = sizeof(BigBuf);
 743         if (size < 2000) continue;
 744         // FSK demodulator
 745         //int askmandemod(uint8_t *BinStream,uint32_t *BitLen,int *clk, int *invert);
 746         bitLen=size;
 747         //Dbprintf("DEBUG: Buffer got");
 748         errCnt = askmandemod(dest,&bitLen,&clk,&invert); //HIDdemodFSK(dest,size,&hi2,&hi,&lo);
 749         //Dbprintf("DEBUG: ASK Got");
 750         WDT_HIT();
 751
 752         if (errCnt>=0){
 753             lo = Em410xDecode(dest,bitLen);
 754             //Dbprintf("DEBUG: EM GOT");
 755             //printEM410x(lo);
 756             if (lo>0){
 757                 Dbprintf("EM TAG ID: %02x%08x - (%05d_%03d_%08d)",(uint32_t)(lo>>32),(uint32_t)lo,(uint32_t)(lo&0xFFFF),(uint32_t)((lo>>16LL) & 0xFF),(uint32_t)(lo & 0xFFFFFF));
 758             }
 759             if (findone){
 760                 if (ledcontrol) LED_A_OFF();
 761                 return;
 762             }
 763         } else{
 764             //Dbprintf("DEBUG: No Tag");
 765         }
 766         WDT_HIT();
 767         lo = 0;
 768         clk=0;
 769         invert=0;
 770         errCnt=0;
 771         size=0;
 772         //SpinDelay(50);
 773     }
 774     DbpString("Stopped");
 775     if (ledcontrol) LED_A_OFF();
 776 }
 777
 778 void CmdIOdemodFSK(int findone, int *high, int *low, int ledcontrol)
 779 {
 780     uint8_t *dest = (uint8_t *)BigBuf;
 781     int idx=0;
 782     uint32_t code=0, code2=0;
 783     uint8_t version=0;
 784     uint8_t facilitycode=0;
 785     uint16_t number=0;
 786     // Configure to go in 125Khz listen mode
 787     LFSetupFPGAForADC(95, true);
 788
 789     while(!BUTTON_PRESS()) {
 790         WDT_HIT();
 791         if (ledcontrol) LED_A_ON();
 792         DoAcquisition125k_internal(-1,true);
 793         //fskdemod and get start index
 794         WDT_HIT();
 795         idx = IOdemodFSK(dest,sizeof(BigBuf));
 796         if (idx>0){
 797             //valid tag found
 798
 799             //Index map
 800             //0           10          20          30          40          50          60
 801             //|           |           |           |           |           |           |
 802             //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
 803             //-----------------------------------------------------------------------------
 804             //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
 805             //
 806             //XSF(version)facility:codeone+codetwo
 807             //Handle the data
 808             if(findone){ //only print binary if we are doing one
 809                 Dbprintf("%d%d%d%d%d%d%d%d %d",dest[idx],   dest[idx+1],   dest[idx+2],dest[idx+3],dest[idx+4],dest[idx+5],dest[idx+6],dest[idx+7],dest[idx+8]);
 810                 Dbprintf("%d%d%d%d%d%d%d%d %d",dest[idx+9], dest[idx+10],dest[idx+11],dest[idx+12],dest[idx+13],dest[idx+14],dest[idx+15],dest[idx+16],dest[idx+17]);
 811                 Dbprintf("%d%d%d%d%d%d%d%d %d",dest[idx+18],dest[idx+19],dest[idx+20],dest[idx+21],dest[idx+22],dest[idx+23],dest[idx+24],dest[idx+25],dest[idx+26]);
 812                 Dbprintf("%d%d%d%d%d%d%d%d %d",dest[idx+27],dest[idx+28],dest[idx+29],dest[idx+30],dest[idx+31],dest[idx+32],dest[idx+33],dest[idx+34],dest[idx+35]);
 813                 Dbprintf("%d%d%d%d%d%d%d%d %d",dest[idx+36],dest[idx+37],dest[idx+38],dest[idx+39],dest[idx+40],dest[idx+41],dest[idx+42],dest[idx+43],dest[idx+44]);
 814                 Dbprintf("%d%d%d%d%d%d%d%d %d",dest[idx+45],dest[idx+46],dest[idx+47],dest[idx+48],dest[idx+49],dest[idx+50],dest[idx+51],dest[idx+52],dest[idx+53]);
 815                 Dbprintf("%d%d%d%d%d%d%d%d %d%d",dest[idx+54],dest[idx+55],dest[idx+56],dest[idx+57],dest[idx+58],dest[idx+59],dest[idx+60],dest[idx+61],dest[idx+62],dest[idx+63]);
 816             }
 817             code = bytebits_to_byte(dest+idx,32);
 818             code2 = bytebits_to_byte(dest+idx+32,32);
 819             version = bytebits_to_byte(dest+idx+27,8); //14,4
 820             facilitycode = bytebits_to_byte(dest+idx+18,8) ;
 821             number = (bytebits_to_byte(dest+idx+36,8)<<8)|(bytebits_to_byte(dest+idx+45,8)); //36,9
 822
 823             Dbprintf("XSF(%02d)%02x:%05d (%08x%08x)",version,facilitycode,number,code,code2);
 824             // if we're only looking for one tag
 825             if (findone){
 826                 if (ledcontrol) LED_A_OFF();
 827                 //LED_A_OFF();
 828                 return;
 829             }
 830             code=code2=0;
 831             version=facilitycode=0;
 832             number=0;
 833             idx=0;
 834         }
 835         WDT_HIT();
 836     }
 837     DbpString("Stopped");
 838     if (ledcontrol) LED_A_OFF();
 839 }
 840
 841 /*------------------------------
 842  * T5555/T5557/T5567 routines
 843  *------------------------------
 844  */
 845
 846 /* T55x7 configuration register definitions */
 847 #define T55x7_POR_DELAY                 0x00000001
 848 #define T55x7_ST_TERMINATOR             0x00000008
 849 #define T55x7_PWD                       0x00000010
 850 #define T55x7_MAXBLOCK_SHIFT            5
 851 #define T55x7_AOR                       0x00000200
 852 #define T55x7_PSKCF_RF_2                0
 853 #define T55x7_PSKCF_RF_4                0x00000400
 854 #define T55x7_PSKCF_RF_8                0x00000800
 855 #define T55x7_MODULATION_DIRECT         0
 856 #define T55x7_MODULATION_PSK1           0x00001000
 857 #define T55x7_MODULATION_PSK2           0x00002000
 858 #define T55x7_MODULATION_PSK3           0x00003000
 859 #define T55x7_MODULATION_FSK1           0x00004000
 860 #define T55x7_MODULATION_FSK2           0x00005000
 861 #define T55x7_MODULATION_FSK1a          0x00006000
 862 #define T55x7_MODULATION_FSK2a          0x00007000
 863 #define T55x7_MODULATION_MANCHESTER     0x00008000
 864 #define T55x7_MODULATION_BIPHASE        0x00010000
 865 #define T55x7_BITRATE_RF_8              0
 866 #define T55x7_BITRATE_RF_16             0x00040000
 867 #define T55x7_BITRATE_RF_32             0x00080000
 868 #define T55x7_BITRATE_RF_40             0x000C0000
 869 #define T55x7_BITRATE_RF_50             0x00100000
 870 #define T55x7_BITRATE_RF_64             0x00140000
 871 #define T55x7_BITRATE_RF_100            0x00180000
 872 #define T55x7_BITRATE_RF_128            0x001C0000
 873
 874 /* T5555 (Q5) configuration register definitions */
 875 #define T5555_ST_TERMINATOR             0x00000001
 876 #define T5555_MAXBLOCK_SHIFT            0x00000001
 877 #define T5555_MODULATION_MANCHESTER     0
 878 #define T5555_MODULATION_PSK1           0x00000010
 879 #define T5555_MODULATION_PSK2           0x00000020
 880 #define T5555_MODULATION_PSK3           0x00000030
 881 #define T5555_MODULATION_FSK1           0x00000040
 882 #define T5555_MODULATION_FSK2           0x00000050
 883 #define T5555_MODULATION_BIPHASE        0x00000060
 884 #define T5555_MODULATION_DIRECT         0x00000070
 885 #define T5555_INVERT_OUTPUT             0x00000080
 886 #define T5555_PSK_RF_2                  0
 887 #define T5555_PSK_RF_4                  0x00000100
 888 #define T5555_PSK_RF_8                  0x00000200
 889 #define T5555_USE_PWD                   0x00000400
 890 #define T5555_USE_AOR                   0x00000800
 891 #define T5555_BITRATE_SHIFT             12
 892 #define T5555_FAST_WRITE                0x00004000
 893 #define T5555_PAGE_SELECT               0x00008000
 894
 895 /*
 896  * Relevant times in microsecond
 897  * To compensate antenna falling times shorten the write times
 898  * and enlarge the gap ones.
 899  */
 900 #define START_GAP 250
 901 #define WRITE_GAP 160
 902 #define WRITE_0   144 // 192
 903 #define WRITE_1   400 // 432 for T55x7; 448 for E5550
 904
 905 // Write one bit to card
 906 void T55xxWriteBit(int bit)
 907 {
 908     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 909     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
 910     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 911     if (bit == 0)
 912         SpinDelayUs(WRITE_0);
 913     else
 914         SpinDelayUs(WRITE_1);
 915     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 916     SpinDelayUs(WRITE_GAP);
 917 }
 918
 919 // Write one card block in page 0, no lock
 920 void T55xxWriteBlock(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t PwdMode)
 921 {
 922     //unsigned int i;  //enio adjustment 12/10/14
 923     uint32_t i;
 924
 925     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 926     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
 927     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 928
 929     // Give it a bit of time for the resonant antenna to settle.
 930     // And for the tag to fully power up
 931     SpinDelay(150);
 932
 933     // Now start writting
 934     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 935     SpinDelayUs(START_GAP);
 936
 937     // Opcode
 938     T55xxWriteBit(1);
 939     T55xxWriteBit(0); //Page 0
 940     if (PwdMode == 1){
 941         // Pwd
 942         for (i = 0x80000000; i != 0; i >>= 1)
 943             T55xxWriteBit(Pwd & i);
 944     }
 945     // Lock bit
 946     T55xxWriteBit(0);
 947
 948     // Data
 949     for (i = 0x80000000; i != 0; i >>= 1)
 950         T55xxWriteBit(Data & i);
 951
 952     // Block
 953     for (i = 0x04; i != 0; i >>= 1)
 954         T55xxWriteBit(Block & i);
 955
 956     // Now perform write (nominal is 5.6 ms for T55x7 and 18ms for E5550,
 957     // so wait a little more)
 958     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
 959     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 960     SpinDelay(20);
 961     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 962 }
 963
 964 // Read one card block in page 0
 965 void T55xxReadBlock(uint32_t Block, uint32_t Pwd, uint8_t PwdMode)
 966 {
 967     uint8_t *dest = (uint8_t *)BigBuf;
 968     //int m=0, i=0; //enio adjustment 12/10/14
 969     uint32_t m=0, i=0;
 970     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 971     m = sizeof(BigBuf);
 972     // Clear destination buffer before sending the command
 973     memset(dest, 128, m);
 974     // Connect the A/D to the peak-detected low-frequency path.
 975     SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
 976     // Now set up the SSC to get the ADC samples that are now streaming at us.
 977     FpgaSetupSsc();
 978
 979     LED_D_ON();
 980     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
 981     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 982
 983     // Give it a bit of time for the resonant antenna to settle.
 984     // And for the tag to fully power up
 985     SpinDelay(150);
 986
 987     // Now start writting
 988     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 989     SpinDelayUs(START_GAP);
 990
 991     // Opcode
 992     T55xxWriteBit(1);
 993     T55xxWriteBit(0); //Page 0
 994     if (PwdMode == 1){
 995         // Pwd
 996         for (i = 0x80000000; i != 0; i >>= 1)
 997             T55xxWriteBit(Pwd & i);
 998     }
 999     // Lock bit
1000     T55xxWriteBit(0);
1001     // Block
1002     for (i = 0x04; i != 0; i >>= 1)
1003         T55xxWriteBit(Block & i);
1004
1005     // Turn field on to read the response
1006     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1007     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
1008
1009     // Now do the acquisition
1010     i = 0;
1011     for(;;) {
1012         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
1013             AT91C_BASE_SSC->SSC_THR = 0x43;
1014         }
1015         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
1016             dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1017             // we don't care about actual value, only if it's more or less than a
1018             // threshold essentially we capture zero crossings for later analysis
1019             //                  if(dest[i] < 127) dest[i] = 0; else dest[i] = 1;
1020             i++;
1021             if (i >= m) break;
1022         }
1023     }
1024
1025     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
1026     LED_D_OFF();
1027     DbpString("DONE!");
1028 }
1029
1030 // Read card traceability data (page 1)
1031 void T55xxReadTrace(void){
1032     uint8_t *dest = (uint8_t *)BigBuf;
1033     int m=0, i=0;
1034
1035     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
1036     m = sizeof(BigBuf);
1037     // Clear destination buffer before sending the command
1038     memset(dest, 128, m);
1039     // Connect the A/D to the peak-detected low-frequency path.
1040     SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
1041     // Now set up the SSC to get the ADC samples that are now streaming at us.
1042     FpgaSetupSsc();
1043
1044     LED_D_ON();
1045     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1046     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
1047
1048     // Give it a bit of time for the resonant antenna to settle.
1049     // And for the tag to fully power up
1050     SpinDelay(150);
1051
1052     // Now start writting
1053     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
1054     SpinDelayUs(START_GAP);
1055
1056     // Opcode
1057     T55xxWriteBit(1);
1058     T55xxWriteBit(1); //Page 1
1059
1060     // Turn field on to read the response
1061     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1062     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
1063
1064     // Now do the acquisition
1065     i = 0;
1066     for(;;) {
1067         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
1068             AT91C_BASE_SSC->SSC_THR = 0x43;
1069         }
1070         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
1071             dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1072             i++;
1073             if (i >= m) break;
1074         }
1075     }
1076
1077     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
1078     LED_D_OFF();
1079     DbpString("DONE!");
1080 }
1081
1082 /*-------------- Cloning routines -----------*/
1083 // Copy HID id to card and setup block 0 config
1084 void CopyHIDtoT55x7(uint32_t hi2, uint32_t hi, uint32_t lo, uint8_t longFMT)
1085 {
1086     int data1=0, data2=0, data3=0, data4=0, data5=0, data6=0; //up to six blocks for long format
1087     int last_block = 0;
1088
1089     if (longFMT){
1090         // Ensure no more than 84 bits supplied
1091         if (hi2>0xFFFFF) {
1092             DbpString("Tags can only have 84 bits.");
1093             return;
1094         }
1095         // Build the 6 data blocks for supplied 84bit ID
1096         last_block = 6;
1097         data1 = 0x1D96A900; // load preamble (1D) & long format identifier (9E manchester encoded)
1098         for (int i=0;i<4;i++) {
1099             if (hi2 & (1<<(19-i)))
1100                 data1 |= (1<<(((3-i)*2)+1)); // 1 -> 10
1101             else
1102                 data1 |= (1<<((3-i)*2)); // 0 -> 01
1103         }
1104
1105         data2 = 0;
1106         for (int i=0;i<16;i++) {
1107             if (hi2 & (1<<(15-i)))
1108                 data2 |= (1<<(((15-i)*2)+1)); // 1 -> 10
1109             else
1110                 data2 |= (1<<((15-i)*2)); // 0 -> 01
1111         }
1112
1113         data3 = 0;
1114         for (int i=0;i<16;i++) {
1115             if (hi & (1<<(31-i)))
1116                 data3 |= (1<<(((15-i)*2)+1)); // 1 -> 10
1117             else
1118                 data3 |= (1<<((15-i)*2)); // 0 -> 01
1119         }
1120
1121         data4 = 0;
1122         for (int i=0;i<16;i++) {
1123             if (hi & (1<<(15-i)))
1124                 data4 |= (1<<(((15-i)*2)+1)); // 1 -> 10
1125             else
1126                 data4 |= (1<<((15-i)*2)); // 0 -> 01
1127         }
1128
1129         data5 = 0;
1130         for (int i=0;i<16;i++) {
1131             if (lo & (1<<(31-i)))
1132                 data5 |= (1<<(((15-i)*2)+1)); // 1 -> 10
1133             else
1134                 data5 |= (1<<((15-i)*2)); // 0 -> 01
1135         }
1136
1137         data6 = 0;
1138         for (int i=0;i<16;i++) {
1139             if (lo & (1<<(15-i)))
1140                 data6 |= (1<<(((15-i)*2)+1)); // 1 -> 10
1141             else
1142                 data6 |= (1<<((15-i)*2)); // 0 -> 01
1143         }
1144     }
1145     else {
1146         // Ensure no more than 44 bits supplied
1147         if (hi>0xFFF) {
1148             DbpString("Tags can only have 44 bits.");
1149             return;
1150         }
1151
1152         // Build the 3 data blocks for supplied 44bit ID
1153         last_block = 3;
1154
1155         data1 = 0x1D000000; // load preamble
1156
1157         for (int i=0;i<12;i++) {
1158             if (hi & (1<<(11-i)))
1159                 data1 |= (1<<(((11-i)*2)+1)); // 1 -> 10
1160             else
1161                 data1 |= (1<<((11-i)*2)); // 0 -> 01
1162         }
1163
1164         data2 = 0;
1165         for (int i=0;i<16;i++) {
1166             if (lo & (1<<(31-i)))
1167                 data2 |= (1<<(((15-i)*2)+1)); // 1 -> 10
1168             else
1169                 data2 |= (1<<((15-i)*2)); // 0 -> 01
1170         }
1171
1172         data3 = 0;
1173         for (int i=0;i<16;i++) {
1174             if (lo & (1<<(15-i)))
1175                 data3 |= (1<<(((15-i)*2)+1)); // 1 -> 10
1176             else
1177                 data3 |= (1<<((15-i)*2)); // 0 -> 01
1178         }
1179     }
1180
1181     LED_D_ON();
1182     // Program the data blocks for supplied ID
1183     // and the block 0 for HID format
1184     T55xxWriteBlock(data1,1,0,0);
1185     T55xxWriteBlock(data2,2,0,0);
1186     T55xxWriteBlock(data3,3,0,0);
1187
1188     if (longFMT) { // if long format there are 6 blocks
1189         T55xxWriteBlock(data4,4,0,0);
1190         T55xxWriteBlock(data5,5,0,0);
1191         T55xxWriteBlock(data6,6,0,0);
1192     }
1193
1194     // Config for HID (RF/50, FSK2a, Maxblock=3 for short/6 for long)
1195     T55xxWriteBlock(T55x7_BITRATE_RF_50    |
1196                     T55x7_MODULATION_FSK2a |
1197                     last_block << T55x7_MAXBLOCK_SHIFT,
1198                     0,0,0);
1199
1200     LED_D_OFF();
1201
1202     DbpString("DONE!");
1203 }
1204
1205 void CopyIOtoT55x7(uint32_t hi, uint32_t lo, uint8_t longFMT)
1206 {
1207     int data1=0, data2=0; //up to six blocks for long format
1208
1209     data1 = hi;  // load preamble
1210     data2 = lo;
1211
1212     LED_D_ON();
1213     // Program the data blocks for supplied ID
1214     // and the block 0 for HID format
1215     T55xxWriteBlock(data1,1,0,0);
1216     T55xxWriteBlock(data2,2,0,0);
1217
1218     //Config Block
1219     T55xxWriteBlock(0x00147040,0,0,0);
1220     LED_D_OFF();
1221
1222     DbpString("DONE!");
1223 }
1224
1225 // Define 9bit header for EM410x tags
1226 #define EM410X_HEADER           0x1FF
1227 #define EM410X_ID_LENGTH        40
1228
1229 void WriteEM410x(uint32_t card, uint32_t id_hi, uint32_t id_lo)
1230 {
1231     int i, id_bit;
1232     uint64_t id = EM410X_HEADER;
1233     uint64_t rev_id = 0;        // reversed ID
1234     int c_parity[4];    // column parity
1235     int r_parity = 0;   // row parity
1236     uint32_t clock = 0;
1237
1238     // Reverse ID bits given as parameter (for simpler operations)
1239     for (i = 0; i < EM410X_ID_LENGTH; ++i) {
1240         if (i < 32) {
1241             rev_id = (rev_id << 1) | (id_lo & 1);
1242             id_lo >>= 1;
1243         } else {
1244             rev_id = (rev_id << 1) | (id_hi & 1);
1245             id_hi >>= 1;
1246         }
1247     }
1248
1249     for (i = 0; i < EM410X_ID_LENGTH; ++i) {
1250         id_bit = rev_id & 1;
1251
1252         if (i % 4 == 0) {
1253             // Don't write row parity bit at start of parsing
1254             if (i)
1255                 id = (id << 1) | r_parity;
1256             // Start counting parity for new row
1257             r_parity = id_bit;
1258         } else {
1259             // Count row parity
1260             r_parity ^= id_bit;
1261         }
1262
1263         // First elements in column?
1264         if (i < 4)
1265             // Fill out first elements
1266             c_parity[i] = id_bit;
1267         else
1268             // Count column parity
1269             c_parity[i % 4] ^= id_bit;
1270
1271         // Insert ID bit
1272         id = (id << 1) | id_bit;
1273         rev_id >>= 1;
1274     }
1275
1276     // Insert parity bit of last row
1277     id = (id << 1) | r_parity;
1278
1279     // Fill out column parity at the end of tag
1280     for (i = 0; i < 4; ++i)
1281         id = (id << 1) | c_parity[i];
1282
1283     // Add stop bit
1284     id <<= 1;
1285
1286     Dbprintf("Started writing %s tag ...", card ? "T55x7":"T5555");
1287     LED_D_ON();
1288
1289     // Write EM410x ID
1290     T55xxWriteBlock((uint32_t)(id >> 32), 1, 0, 0);
1291     T55xxWriteBlock((uint32_t)id, 2, 0, 0);
1292
1293     // Config for EM410x (RF/64, Manchester, Maxblock=2)
1294     if (card) {
1295         // Clock rate is stored in bits 8-15 of the card value
1296         clock = (card & 0xFF00) >> 8;
1297         Dbprintf("Clock rate: %d", clock);
1298         switch (clock)
1299         {
1300         case 32:
1301             clock = T55x7_BITRATE_RF_32;
1302             break;
1303         case 16:
1304             clock = T55x7_BITRATE_RF_16;
1305             break;
1306         case 0:
1307             // A value of 0 is assumed to be 64 for backwards-compatibility
1308             // Fall through...
1309         case 64:
1310             clock = T55x7_BITRATE_RF_64;
1311             break;
1312         default:
1313             Dbprintf("Invalid clock rate: %d", clock);
1314             return;
1315         }
1316
1317         // Writing configuration for T55x7 tag
1318         T55xxWriteBlock(clock       |
1319                         T55x7_MODULATION_MANCHESTER |
1320                         2 << T55x7_MAXBLOCK_SHIFT,
1321                         0, 0, 0);
1322     }
1323     else
1324         // Writing configuration for T5555(Q5) tag
1325         T55xxWriteBlock(0x1F << T5555_BITRATE_SHIFT |
1326                         T5555_MODULATION_MANCHESTER   |
1327                         2 << T5555_MAXBLOCK_SHIFT,
1328                         0, 0, 0);
1329
1330     LED_D_OFF();
1331     Dbprintf("Tag %s written with 0x%08x%08x\n", card ? "T55x7":"T5555",
1332              (uint32_t)(id >> 32), (uint32_t)id);
1333 }
1334
1335 // Clone Indala 64-bit tag by UID to T55x7
1336 void CopyIndala64toT55x7(int hi, int lo)
1337 {
1338     //Program the 2 data blocks for supplied 64bit UID
1339     // and the block 0 for Indala64 format
1340     T55xxWriteBlock(hi,1,0,0);
1341     T55xxWriteBlock(lo,2,0,0);
1342     //Config for Indala (RF/32;PSK1 with RF/2;Maxblock=2)
1343     T55xxWriteBlock(T55x7_BITRATE_RF_32    |
1344                     T55x7_MODULATION_PSK1 |
1345                     2 << T55x7_MAXBLOCK_SHIFT,
1346                     0, 0, 0);
1347     //Alternative config for Indala (Extended mode;RF/32;PSK1 with RF/2;Maxblock=2;Inverse data)
1348     //  T5567WriteBlock(0x603E1042,0);
1349
1350     DbpString("DONE!");
1351 }
1352
1353 void CopyIndala224toT55x7(int uid1, int uid2, int uid3, int uid4, int uid5, int uid6, int uid7)
1354 {
1355     //Program the 7 data blocks for supplied 224bit UID
1356     // and the block 0 for Indala224 format
1357     T55xxWriteBlock(uid1,1,0,0);
1358     T55xxWriteBlock(uid2,2,0,0);
1359     T55xxWriteBlock(uid3,3,0,0);
1360     T55xxWriteBlock(uid4,4,0,0);
1361     T55xxWriteBlock(uid5,5,0,0);
1362     T55xxWriteBlock(uid6,6,0,0);
1363     T55xxWriteBlock(uid7,7,0,0);
1364     //Config for Indala (RF/32;PSK1 with RF/2;Maxblock=7)
1365     T55xxWriteBlock(T55x7_BITRATE_RF_32    |
1366                     T55x7_MODULATION_PSK1 |
1367                     7 << T55x7_MAXBLOCK_SHIFT,
1368                     0,0,0);
1369     //Alternative config for Indala (Extended mode;RF/32;PSK1 with RF/2;Maxblock=7;Inverse data)
1370     //  T5567WriteBlock(0x603E10E2,0);
1371
1372     DbpString("DONE!");
1373 }
1374
1375
1376 #define abs(x) ( ((x)<0) ? -(x) : (x) )
1377 #define max(x,y) ( x<y ? y:x)
1378
1379 int DemodPCF7931(uint8_t **outBlocks) {
1380     uint8_t BitStream[256];
1381     uint8_t Blocks[8][16];
1382     uint8_t *GraphBuffer = (uint8_t *)BigBuf;
1383     int GraphTraceLen = sizeof(BigBuf);
1384     int i, j, lastval, bitidx, half_switch;
1385     int clock = 64;
1386     int tolerance = clock / 8;
1387     int pmc, block_done;
1388     int lc, warnings = 0;
1389     int num_blocks = 0;
1390     int lmin=128, lmax=128;
1391     uint8_t dir;
1392
1393     AcquireRawAdcSamples125k(0);
1394
1395     lmin = 64;
1396     lmax = 192;
1397
1398     i = 2;
1399
1400     /* Find first local max/min */
1401     if(GraphBuffer[1] > GraphBuffer[0]) {
1402         while(i < GraphTraceLen) {
1403             if( !(GraphBuffer[i] > GraphBuffer[i-1]) && GraphBuffer[i] > lmax)
1404                 break;
1405             i++;
1406         }
1407         dir = 0;
1408     }
1409     else {
1410         while(i < GraphTraceLen) {
1411             if( !(GraphBuffer[i] < GraphBuffer[i-1]) && GraphBuffer[i] < lmin)
1412                 break;
1413             i++;
1414         }
1415         dir = 1;
1416     }
1417
1418     lastval = i++;
1419     half_switch = 0;
1420     pmc = 0;
1421     block_done = 0;
1422
1423     for (bitidx = 0; i < GraphTraceLen; i++)
1424     {
1425         if ( (GraphBuffer[i-1] > GraphBuffer[i] && dir == 1 && GraphBuffer[i] > lmax) || (GraphBuffer[i-1] < GraphBuffer[i] && dir == 0 && GraphBuffer[i] < lmin))
1426         {
1427             lc = i - lastval;
1428             lastval = i;
1429
1430             // Switch depending on lc length:
1431             // Tolerance is 1/8 of clock rate (arbitrary)
1432             if (abs(lc-clock/4) < tolerance) {
1433                 // 16T0
1434                 if((i - pmc) == lc) { /* 16T0 was previous one */
1435                     /* It's a PMC ! */
1436                     i += (128+127+16+32+33+16)-1;
1437                     lastval = i;
1438                     pmc = 0;
1439                     block_done = 1;
1440                 }
1441                 else {
1442                     pmc = i;
1443                 }
1444             } else if (abs(lc-clock/2) < tolerance) {
1445                 // 32TO
1446                 if((i - pmc) == lc) { /* 16T0 was previous one */
1447                     /* It's a PMC ! */
1448                     i += (128+127+16+32+33)-1;
1449                     lastval = i;
1450                     pmc = 0;
1451                     block_done = 1;
1452                 }
1453                 else if(half_switch == 1) {
1454                     BitStream[bitidx++] = 0;
1455                     half_switch = 0;
1456                 }
1457                 else
1458                     half_switch++;
1459             } else if (abs(lc-clock) < tolerance) {
1460                 // 64TO
1461                 BitStream[bitidx++] = 1;
1462             } else {
1463                 // Error
1464                 warnings++;
1465                 if (warnings > 10)
1466                 {
1467                     Dbprintf("Error: too many detection errors, aborting.");
1468                     return 0;
1469                 }
1470             }
1471
1472             if(block_done == 1) {
1473                 if(bitidx == 128) {
1474                     for(j=0; j<16; j++) {
1475                         Blocks[num_blocks][j] = 128*BitStream[j*8+7]+
1476                                 64*BitStream[j*8+6]+
1477                                 32*BitStream[j*8+5]+
1478                                 16*BitStream[j*8+4]+
1479                                 8*BitStream[j*8+3]+
1480                                 4*BitStream[j*8+2]+
1481                                 2*BitStream[j*8+1]+
1482                                 BitStream[j*8];
1483                     }
1484                     num_blocks++;
1485                 }
1486                 bitidx = 0;
1487                 block_done = 0;
1488                 half_switch = 0;
1489             }
1490             if(i < GraphTraceLen)
1491             {
1492                 if (GraphBuffer[i-1] > GraphBuffer[i]) dir=0;
1493                 else dir = 1;
1494             }
1495         }
1496         if(bitidx==255)
1497             bitidx=0;
1498         warnings = 0;
1499         if(num_blocks == 4) break;
1500     }
1501     memcpy(outBlocks, Blocks, 16*num_blocks);
1502     return num_blocks;
1503 }
1504
1505 int IsBlock0PCF7931(uint8_t *Block) {
1506     // Assume RFU means 0 :)
1507     if((memcmp(Block, "\x00\x00\x00\x00\x00\x00\x00\x01", 8) == 0) && memcmp(Block+9, "\x00\x00\x00\x00\x00\x00\x00", 7) == 0) // PAC enabled
1508         return 1;
1509     if((memcmp(Block+9, "\x00\x00\x00\x00\x00\x00\x00", 7) == 0) && Block[7] == 0) // PAC disabled, can it *really* happen ?
1510         return 1;
1511     return 0;
1512 }
1513
1514 int IsBlock1PCF7931(uint8_t *Block) {
1515     // Assume RFU means 0 :)
1516     if(Block[10] == 0 && Block[11] == 0 && Block[12] == 0 && Block[13] == 0)
1517         if((Block[14] & 0x7f) <= 9 && Block[15] <= 9)
1518             return 1;
1519
1520     return 0;
1521 }
1522 #define ALLOC 16
1523
1524 void ReadPCF7931() {
1525     uint8_t Blocks[8][17];
1526     uint8_t tmpBlocks[4][16];
1527     int i, j, ind, ind2, n;
1528     int num_blocks = 0;
1529     int max_blocks = 8;
1530     int ident = 0;
1531     int error = 0;
1532     int tries = 0;
1533
1534     memset(Blocks, 0, 8*17*sizeof(uint8_t));
1535
1536     do {
1537         memset(tmpBlocks, 0, 4*16*sizeof(uint8_t));
1538         n = DemodPCF7931((uint8_t**)tmpBlocks);
1539         if(!n)
1540             error++;
1541         if(error==10 && num_blocks == 0) {
1542             Dbprintf("Error, no tag or bad tag");
1543             return;
1544         }
1545         else if (tries==20 || error==10) {
1546             Dbprintf("Error reading the tag");
1547             Dbprintf("Here is the partial content");
1548             goto end;
1549         }
1550
1551         for(i=0; i<n; i++)
1552             Dbprintf("(dbg) %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
1553                      tmpBlocks[i][0], tmpBlocks[i][1], tmpBlocks[i][2], tmpBlocks[i][3], tmpBlocks[i][4], tmpBlocks[i][5], tmpBlocks[i][6], tmpBlocks[i][7],
1554                     tmpBlocks[i][8], tmpBlocks[i][9], tmpBlocks[i][10], tmpBlocks[i][11], tmpBlocks[i][12], tmpBlocks[i][13], tmpBlocks[i][14], tmpBlocks[i][15]);
1555         if(!ident) {
1556             for(i=0; i<n; i++) {
1557                 if(IsBlock0PCF7931(tmpBlocks[i])) {
1558                     // Found block 0 ?
1559                     if(i < n-1 && IsBlock1PCF7931(tmpBlocks[i+1])) {
1560                         // Found block 1!
1561                         // \o/
1562                         ident = 1;
1563                         memcpy(Blocks[0], tmpBlocks[i], 16);
1564                         Blocks[0][ALLOC] = 1;
1565                         memcpy(Blocks[1], tmpBlocks[i+1], 16);
1566                         Blocks[1][ALLOC] = 1;
1567                         max_blocks = max((Blocks[1][14] & 0x7f), Blocks[1][15]) + 1;
1568                         // Debug print
1569                         Dbprintf("(dbg) Max blocks: %d", max_blocks);
1570                         num_blocks = 2;
1571                         // Handle following blocks
1572                         for(j=i+2, ind2=2; j!=i; j++, ind2++, num_blocks++) {
1573                             if(j==n) j=0;
1574                             if(j==i) break;
1575                             memcpy(Blocks[ind2], tmpBlocks[j], 16);
1576                             Blocks[ind2][ALLOC] = 1;
1577                         }
1578                         break;
1579                     }
1580                 }
1581             }
1582         }
1583         else {
1584             for(i=0; i<n; i++) { // Look for identical block in known blocks
1585                 if(memcmp(tmpBlocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) { // Block is not full of 00
1586                     for(j=0; j<max_blocks; j++) {
1587                         if(Blocks[j][ALLOC] == 1 && !memcmp(tmpBlocks[i], Blocks[j], 16)) {
1588                             // Found an identical block
1589                             for(ind=i-1,ind2=j-1; ind >= 0; ind--,ind2--) {
1590                                 if(ind2 < 0)
1591                                     ind2 = max_blocks;
1592                                 if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
1593                                     // Dbprintf("Tmp %d -> Block %d", ind, ind2);
1594                                     memcpy(Blocks[ind2], tmpBlocks[ind], 16);
1595                                     Blocks[ind2][ALLOC] = 1;
1596                                     num_blocks++;
1597                                     if(num_blocks == max_blocks) goto end;
1598                                 }
1599                             }
1600                             for(ind=i+1,ind2=j+1; ind < n; ind++,ind2++) {
1601                                 if(ind2 > max_blocks)
1602                                     ind2 = 0;
1603                                 if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
1604                                     // Dbprintf("Tmp %d -> Block %d", ind, ind2);
1605                                     memcpy(Blocks[ind2], tmpBlocks[ind], 16);
1606                                     Blocks[ind2][ALLOC] = 1;
1607                                     num_blocks++;
1608                                     if(num_blocks == max_blocks) goto end;
1609                                 }
1610                             }
1611                         }
1612                     }
1613                 }
1614             }
1615         }
1616         tries++;
1617         if (BUTTON_PRESS()) return;
1618     } while (num_blocks != max_blocks);
1619 end:
1620     Dbprintf("-----------------------------------------");
1621     Dbprintf("Memory content:");
1622     Dbprintf("-----------------------------------------");
1623     for(i=0; i<max_blocks; i++) {
1624         if(Blocks[i][ALLOC]==1)
1625             Dbprintf("%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
1626                      Blocks[i][0], Blocks[i][1], Blocks[i][2], Blocks[i][3], Blocks[i][4], Blocks[i][5], Blocks[i][6], Blocks[i][7],
1627                     Blocks[i][8], Blocks[i][9], Blocks[i][10], Blocks[i][11], Blocks[i][12], Blocks[i][13], Blocks[i][14], Blocks[i][15]);
1628         else
1629             Dbprintf("<missing block %d>", i);
1630     }
1631     Dbprintf("-----------------------------------------");
1632
1633     return ;
1634 }
1635
1636
1637 //-----------------------------------
1638 // EM4469 / EM4305 routines
1639 //-----------------------------------
1640 #define FWD_CMD_LOGIN 0xC //including the even parity, binary mirrored
1641 #define FWD_CMD_WRITE 0xA
1642 #define FWD_CMD_READ 0x9
1643 #define FWD_CMD_DISABLE 0x5
1644
1645
1646 uint8_t forwardLink_data[64]; //array of forwarded bits
1647 uint8_t * forward_ptr; //ptr for forward message preparation
1648 uint8_t fwd_bit_sz; //forwardlink bit counter
1649 uint8_t * fwd_write_ptr; //forwardlink bit pointer
1650
1651 //====================================================================
1652 // prepares command bits
1653 // see EM4469 spec
1654 //====================================================================
1655 //--------------------------------------------------------------------
1656 uint8_t Prepare_Cmd( uint8_t cmd ) {
1657     //--------------------------------------------------------------------
1658
1659     *forward_ptr++ = 0; //start bit
1660     *forward_ptr++ = 0; //second pause for 4050 code
1661
1662     *forward_ptr++ = cmd;
1663     cmd >>= 1;
1664     *forward_ptr++ = cmd;
1665     cmd >>= 1;
1666     *forward_ptr++ = cmd;
1667     cmd >>= 1;
1668     *forward_ptr++ = cmd;
1669
1670     return 6; //return number of emited bits
1671 }
1672
1673 //====================================================================
1674 // prepares address bits
1675 // see EM4469 spec
1676 //====================================================================
1677
1678 //--------------------------------------------------------------------
1679 uint8_t Prepare_Addr( uint8_t addr ) {
1680     //--------------------------------------------------------------------
1681
1682     register uint8_t line_parity;
1683
1684     uint8_t i;
1685     line_parity = 0;
1686     for(i=0;i<6;i++) {
1687         *forward_ptr++ = addr;
1688         line_parity ^= addr;
1689         addr >>= 1;
1690     }
1691
1692     *forward_ptr++ = (line_parity & 1);
1693
1694     return 7; //return number of emited bits
1695 }
1696
1697 //====================================================================
1698 // prepares data bits intreleaved with parity bits
1699 // see EM4469 spec
1700 //====================================================================
1701
1702 //--------------------------------------------------------------------
1703 uint8_t Prepare_Data( uint16_t data_low, uint16_t data_hi) {
1704     //--------------------------------------------------------------------
1705
1706     register uint8_t line_parity;
1707     register uint8_t column_parity;
1708     register uint8_t i, j;
1709     register uint16_t data;
1710
1711     data = data_low;
1712     column_parity = 0;
1713
1714     for(i=0; i<4; i++) {
1715         line_parity = 0;
1716         for(j=0; j<8; j++) {
1717             line_parity ^= data;
1718             column_parity ^= (data & 1) << j;
1719             *forward_ptr++ = data;
1720             data >>= 1;
1721         }
1722         *forward_ptr++ = line_parity;
1723         if(i == 1)
1724             data = data_hi;
1725     }
1726
1727     for(j=0; j<8; j++) {
1728         *forward_ptr++ = column_parity;
1729         column_parity >>= 1;
1730     }
1731     *forward_ptr = 0;
1732
1733     return 45; //return number of emited bits
1734 }
1735
1736 //====================================================================
1737 // Forward Link send function
1738 // Requires: forwarLink_data filled with valid bits (1 bit per byte)
1739 // fwd_bit_count set with number of bits to be sent
1740 //====================================================================
1741 void SendForward(uint8_t fwd_bit_count) {
1742
1743     fwd_write_ptr = forwardLink_data;
1744     fwd_bit_sz = fwd_bit_count;
1745
1746     LED_D_ON();
1747
1748     //Field on
1749     FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
1750     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1751     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
1752
1753     // Give it a bit of time for the resonant antenna to settle.
1754     // And for the tag to fully power up
1755     SpinDelay(150);
1756
1757     // force 1st mod pulse (start gap must be longer for 4305)
1758     fwd_bit_sz--; //prepare next bit modulation
1759     fwd_write_ptr++;
1760     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
1761     SpinDelayUs(55*8); //55 cycles off (8us each)for 4305
1762     FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1763     FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);//field on
1764     SpinDelayUs(16*8); //16 cycles on (8us each)
1765
1766     // now start writting
1767     while(fwd_bit_sz-- > 0) { //prepare next bit modulation
1768         if(((*fwd_write_ptr++) & 1) == 1)
1769             SpinDelayUs(32*8); //32 cycles at 125Khz (8us each)
1770         else {
1771             //These timings work for 4469/4269/4305 (with the 55*8 above)
1772             FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
1773             SpinDelayUs(23*8); //16-4 cycles off (8us each)
1774             FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
1775             FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);//field on
1776             SpinDelayUs(9*8); //16 cycles on (8us each)
1777         }
1778     }
1779 }
1780
1781
1782 void EM4xLogin(uint32_t Password) {
1783
1784     uint8_t fwd_bit_count;
1785
1786     forward_ptr = forwardLink_data;
1787     fwd_bit_count = Prepare_Cmd( FWD_CMD_LOGIN );
1788     fwd_bit_count += Prepare_Data( Password&0xFFFF, Password>>16 );
1789
1790     SendForward(fwd_bit_count);
1791
1792     //Wait for command to complete
1793     SpinDelay(20);
1794
1795 }
1796
1797 void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
1798
1799     uint8_t fwd_bit_count;
1800     uint8_t *dest = (uint8_t *)BigBuf;
1801     int m=0, i=0;
1802
1803     //If password mode do login
1804     if (PwdMode == 1) EM4xLogin(Pwd);
1805
1806     forward_ptr = forwardLink_data;
1807     fwd_bit_count = Prepare_Cmd( FWD_CMD_READ );
1808     fwd_bit_count += Prepare_Addr( Address );
1809
1810     m = sizeof(BigBuf);
1811     // Clear destination buffer before sending the command
1812     memset(dest, 128, m);
1813     // Connect the A/D to the peak-detected low-frequency path.
1814     SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
1815     // Now set up the SSC to get the ADC samples that are now streaming at us.
1816     FpgaSetupSsc();
1817
1818     SendForward(fwd_bit_count);
1819
1820     // Now do the acquisition
1821     i = 0;
1822     for(;;) {
1823         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
1824             AT91C_BASE_SSC->SSC_THR = 0x43;
1825         }
1826         if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
1827             dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
1828             i++;
1829             if (i >= m) break;
1830         }
1831     }
1832     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
1833     LED_D_OFF();
1834 }
1835
1836 void EM4xWriteWord(uint32_t Data, uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
1837
1838     uint8_t fwd_bit_count;
1839
1840     //If password mode do login
1841     if (PwdMode == 1) EM4xLogin(Pwd);
1842
1843     forward_ptr = forwardLink_data;
1844     fwd_bit_count = Prepare_Cmd( FWD_CMD_WRITE );
1845     fwd_bit_count += Prepare_Addr( Address );
1846     fwd_bit_count += Prepare_Data( Data&0xFFFF, Data>>16 );
1847
1848     SendForward(fwd_bit_count);
1849
1850     //Wait for write to complete
1851     SpinDelay(20);
1852     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
1853     LED_D_OFF();
1854 }