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