]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - armsrc/lfops.c
Fixed undecimation command
[proxmark3-svn] / armsrc / lfops.c
index f9aee43e0fb095d28acfbb1160dcb040b626f7cc..43af4eed4d39048359fbab6f8ab6a4631dc7a1a7 100644 (file)
-//-----------------------------------------------------------------------------\r
-// Miscellaneous routines for low frequency tag operations.\r
-// Tags supported here so far are Texas Instruments (TI), HID\r
-// Also routines for raw mode reading/simulating of LF waveform\r
-//\r
-//-----------------------------------------------------------------------------\r
-#include <proxmark3.h>\r
-#include "apps.h"\r
-#include "../common/crc16.c"\r
-\r
-void AcquireRawAdcSamples125k(BOOL at134khz)\r
-{\r
-       if(at134khz) {\r
-               FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz\r
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-       } else {\r
-               FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz\r
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-       }\r
-\r
-       // Connect the A/D to the peak-detected low-frequency path.\r
-       SetAdcMuxFor(GPIO_MUXSEL_LOPKD);\r
-\r
-       // Give it a bit of time for the resonant antenna to settle.\r
-       SpinDelay(50);\r
-\r
-       // Now set up the SSC to get the ADC samples that are now streaming at us.\r
-       FpgaSetupSsc();\r
-\r
-       // Now call the acquisition routine\r
-       DoAcquisition125k(at134khz);\r
-}\r
-\r
-// split into two routines so we can avoid timing issues after sending commands //\r
-void DoAcquisition125k(BOOL at134khz)\r
-{\r
-       BYTE *dest = (BYTE *)BigBuf;\r
-       int n = sizeof(BigBuf);\r
-       int i;\r
-\r
-       memset(dest,0,n);\r
-       i = 0;\r
-       for(;;) {\r
-               if(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-                       SSC_TRANSMIT_HOLDING = 0x43;\r
-                       LED_D_ON();\r
-               }\r
-               if(SSC_STATUS & (SSC_STATUS_RX_READY)) {\r
-                       dest[i] = (BYTE)SSC_RECEIVE_HOLDING;\r
-                       i++;\r
-                       LED_D_OFF();\r
-                       if(i >= n) {\r
-                               break;\r
-                       }\r
-               }\r
-       }\r
-       DbpIntegers(dest[0], dest[1], at134khz);\r
-}\r
-\r
-void ModThenAcquireRawAdcSamples125k(int delay_off,int period_0,int period_1,BYTE *command)\r
-{\r
-       BOOL at134khz;\r
-\r
-       // see if 'h' was specified\r
-       if(command[strlen((char *) command) - 1] == 'h')\r
-               at134khz= TRUE;\r
-       else\r
-               at134khz= FALSE;\r
-\r
-       if(at134khz) {\r
-               FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz\r
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-       } else {\r
-               FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz\r
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-       }\r
-\r
-       // Give it a bit of time for the resonant antenna to settle.\r
-       SpinDelay(50);\r
-\r
-       // Now set up the SSC to get the ADC samples that are now streaming at us.\r
-       FpgaSetupSsc();\r
-\r
-       // now modulate the reader field\r
-       while(*command != '\0' && *command != ' ')\r
-               {\r
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);\r
-               LED_D_OFF();\r
-               SpinDelayUs(delay_off);\r
-               if(at134khz) {\r
-                       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz\r
-                       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-               } else {\r
-                       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz\r
-                       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-               }\r
-               LED_D_ON();\r
-               if(*(command++) == '0')\r
-                       SpinDelayUs(period_0);\r
-               else\r
-                       SpinDelayUs(period_1);\r
-               }\r
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);\r
-       LED_D_OFF();\r
-       SpinDelayUs(delay_off);\r
-       if(at134khz) {\r
-               FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz\r
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-       } else {\r
-               FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz\r
-               FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-       }\r
-\r
-       // now do the read\r
-       DoAcquisition125k(at134khz);\r
-}\r
-\r
-/* blank r/w tag data stream\r
-...0000000000000000 01111111\r
-1010101010101010101010101010101010101010101010101010101010101010\r
-0011010010100001\r
-01111111\r
-101010101010101[0]000...\r
-\r
-[5555fe852c5555555555555555fe0000]\r
-*/\r
-void ReadTItag()\r
-{\r
-       // some hardcoded initial params\r
-       // when we read a TI tag we sample the zerocross line at 2Mhz\r
-       // TI tags modulate a 1 as 16 cycles of 123.2Khz\r
-       // TI tags modulate a 0 as 16 cycles of 134.2Khz\r
-       #define FSAMPLE 2000000\r
-       #define FREQLO 123200\r
-       #define FREQHI 134200\r
-\r
-       signed char *dest = (signed char *)BigBuf;\r
-       int n = sizeof(BigBuf);\r
-//     int *dest = GraphBuffer;\r
-//     int n = GraphTraceLen;\r
-\r
-       // 128 bit shift register [shift3:shift2:shift1:shift0]\r
-       DWORD shift3 = 0, shift2 = 0, shift1 = 0, shift0 = 0;\r
-\r
-       int i, cycles=0, samples=0;\r
-       // how many sample points fit in 16 cycles of each frequency\r
-       DWORD sampleslo = (FSAMPLE<<4)/FREQLO, sampleshi = (FSAMPLE<<4)/FREQHI;\r
-       // when to tell if we're close enough to one freq or another\r
-       DWORD threshold = (sampleslo - sampleshi + 1)>>1;\r
-\r
-       // TI tags charge at 134.2Khz\r
-       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz\r
-\r
-       // Place FPGA in passthrough mode, in this mode the CROSS_LO line\r
-       // connects to SSP_DIN and the SSP_DOUT logic level controls\r
-       // whether we're modulating the antenna (high)\r
-       // or listening to the antenna (low)\r
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);\r
-\r
-       // get TI tag data into the buffer\r
-       AcquireTiType();\r
-\r
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);\r
-\r
-       for (i=0; i<n-1; i++) {\r
-               // count cycles by looking for lo to hi zero crossings\r
-               if ( (dest[i]<0) && (dest[i+1]>0) ) {\r
-                       cycles++;\r
-                       // after 16 cycles, measure the frequency\r
-                       if (cycles>15) {\r
-                               cycles=0;\r
-                               samples=i-samples; // number of samples in these 16 cycles\r
-\r
-                               // TI bits are coming to us lsb first so shift them\r
-                               // right through our 128 bit right shift register\r
-                         shift0 = (shift0>>1) | (shift1 << 31);\r
-                         shift1 = (shift1>>1) | (shift2 << 31);\r
-                         shift2 = (shift2>>1) | (shift3 << 31);\r
-                         shift3 >>= 1;\r
-\r
-                               // check if the cycles fall close to the number\r
-                               // expected for either the low or high frequency\r
-                               if ( (samples>(sampleslo-threshold)) && (samples<(sampleslo+threshold)) ) {\r
-                                       // low frequency represents a 1\r
-                                       shift3 |= (1<<31);\r
-                               } else if ( (samples>(sampleshi-threshold)) && (samples<(sampleshi+threshold)) ) {\r
-                                       // high frequency represents a 0\r
-                               } else {\r
-                                       // probably detected a gay waveform or noise\r
-                                       // use this as gaydar or discard shift register and start again\r
-                                       shift3 = shift2 = shift1 = shift0 = 0;\r
-                               }\r
-                               samples = i;\r
-\r
-                               // for each bit we receive, test if we've detected a valid tag\r
-\r
-                               // if we see 17 zeroes followed by 6 ones, we might have a tag\r
-                               // remember the bits are backwards\r
-                               if ( ((shift0 & 0x7fffff) == 0x7e0000) ) {\r
-                                       // if start and end bytes match, we have a tag so break out of the loop\r
-                                       if ( ((shift0>>16)&0xff) == ((shift3>>8)&0xff) ) {\r
-                                               cycles = 0xF0B; //use this as a flag (ugly but whatever)\r
-                                               break;\r
-                                       }\r
-                               }\r
-                       }\r
-               }\r
-       }\r
-\r
-       // if flag is set we have a tag\r
-       if (cycles!=0xF0B) {\r
-               DbpString("Info: No valid tag detected.");\r
-       } else {\r
-         // put 64 bit data into shift1 and shift0\r
-         shift0 = (shift0>>24) | (shift1 << 8);\r
-         shift1 = (shift1>>24) | (shift2 << 8);\r
-\r
-               // align 16 bit crc into lower half of shift2\r
-         shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;\r
-\r
-               // if r/w tag, check ident match\r
-               if ( shift3&(1<<15) ) {\r
-                       DbpString("Info: TI tag is rewriteable");\r
-                       // only 15 bits compare, last bit of ident is not valid\r
-                       if ( ((shift3>>16)^shift0)&0x7fff ) {\r
-                               DbpString("Error: Ident mismatch!");\r
-                       } else {\r
-                               DbpString("Info: TI tag ident is valid");\r
-                       }\r
-               } else {\r
-                       DbpString("Info: TI tag is readonly");\r
-               }\r
-\r
-               // WARNING the order of the bytes in which we calc crc below needs checking\r
-               // i'm 99% sure the crc algorithm is correct, but it may need to eat the\r
-               // bytes in reverse or something\r
-               // calculate CRC\r
-               DWORD crc=0;\r
-\r
-               crc = update_crc16(crc, (shift0)&0xff);\r
-               crc = update_crc16(crc, (shift0>>8)&0xff);\r
-               crc = update_crc16(crc, (shift0>>16)&0xff);\r
-               crc = update_crc16(crc, (shift0>>24)&0xff);\r
-               crc = update_crc16(crc, (shift1)&0xff);\r
-               crc = update_crc16(crc, (shift1>>8)&0xff);\r
-               crc = update_crc16(crc, (shift1>>16)&0xff);\r
-               crc = update_crc16(crc, (shift1>>24)&0xff);\r
-\r
-               DbpString("Info: Tag data_hi, data_lo, crc = ");\r
-               DbpIntegers(shift1, shift0, shift2&0xffff);\r
-               if (crc != (shift2&0xffff)) {\r
-                       DbpString("Error: CRC mismatch, expected");\r
-                       DbpIntegers(0, 0, crc);\r
-               } else {\r
-                       DbpString("Info: CRC is good");\r
-               }\r
-       }\r
-}\r
-\r
-void WriteTIbyte(BYTE b)\r
-{\r
-       int i = 0;\r
-\r
-       // modulate 8 bits out to the antenna\r
-       for (i=0; i<8; i++)\r
-       {\r
-               if (b&(1<<i)) {\r
-                       // stop modulating antenna\r
-                       PIO_OUTPUT_DATA_CLEAR = (1<<GPIO_SSC_DOUT);\r
-                       SpinDelayUs(1000);\r
-                       // modulate antenna\r
-                       PIO_OUTPUT_DATA_SET = (1<<GPIO_SSC_DOUT);\r
-                       SpinDelayUs(1000);\r
-               } else {\r
-                       // stop modulating antenna\r
-                       PIO_OUTPUT_DATA_CLEAR = (1<<GPIO_SSC_DOUT);\r
-                       SpinDelayUs(300);\r
-                       // modulate antenna\r
-                       PIO_OUTPUT_DATA_SET = (1<<GPIO_SSC_DOUT);\r
-                       SpinDelayUs(1700);\r
-               }\r
-       }\r
-}\r
-\r
-void AcquireTiType(void)\r
-{\r
-       int i, j, n;\r
-       // tag transmission is <20ms, sampling at 2M gives us 40K samples max\r
-       // each sample is 1 bit stuffed into a DWORD so we need 1250 DWORDS\r
-       #define TIBUFLEN 1250\r
-\r
-       // clear buffer\r
-       memset(BigBuf,0,sizeof(BigBuf));\r
-\r
-       // Set up the synchronous serial port\r
-  PIO_DISABLE = (1<<GPIO_SSC_DIN);\r
-  PIO_PERIPHERAL_A_SEL = (1<<GPIO_SSC_DIN);\r
-\r
-       // steal this pin from the SSP and use it to control the modulation\r
-  PIO_ENABLE = (1<<GPIO_SSC_DOUT);\r
-       PIO_OUTPUT_ENABLE       = (1<<GPIO_SSC_DOUT);\r
-\r
-  SSC_CONTROL = SSC_CONTROL_RESET;\r
-  SSC_CONTROL = SSC_CONTROL_RX_ENABLE | SSC_CONTROL_TX_ENABLE;\r
-\r
-  // Sample at 2 Mbit/s, so TI tags are 16.2 vs. 14.9 clocks long\r
-  // 48/2 = 24 MHz clock must be divided by 12\r
-  SSC_CLOCK_DIVISOR = 12;\r
-\r
-  SSC_RECEIVE_CLOCK_MODE = SSC_CLOCK_MODE_SELECT(0);\r
-       SSC_RECEIVE_FRAME_MODE = SSC_FRAME_MODE_BITS_IN_WORD(32) | SSC_FRAME_MODE_MSB_FIRST;\r
-       SSC_TRANSMIT_CLOCK_MODE = 0;\r
-       SSC_TRANSMIT_FRAME_MODE = 0;\r
-\r
-       LED_D_ON();\r
-\r
-       // modulate antenna\r
-       PIO_OUTPUT_DATA_SET = (1<<GPIO_SSC_DOUT);\r
-\r
-       // Charge TI tag for 50ms.\r
-       SpinDelay(50);\r
-\r
-       // stop modulating antenna and listen\r
-       PIO_OUTPUT_DATA_CLEAR = (1<<GPIO_SSC_DOUT);\r
-\r
-       LED_D_OFF();\r
-\r
-       i = 0;\r
-       for(;;) {\r
-                       if(SSC_STATUS & SSC_STATUS_RX_READY) {\r
-                                       BigBuf[i] = SSC_RECEIVE_HOLDING;        // store 32 bit values in buffer\r
-                                       i++; if(i >= TIBUFLEN) break;\r
-                       }\r
-                       WDT_HIT();\r
-       }\r
-\r
-       // return stolen pin to SSP\r
-       PIO_DISABLE = (1<<GPIO_SSC_DOUT);\r
-       PIO_PERIPHERAL_A_SEL = (1<<GPIO_SSC_DIN) | (1<<GPIO_SSC_DOUT);\r
-\r
-       char *dest = (char *)BigBuf;\r
-       n = TIBUFLEN*32;\r
-       // unpack buffer\r
-       for (i=TIBUFLEN-1; i>=0; i--) {\r
-//             DbpIntegers(0, 0, BigBuf[i]);\r
-               for (j=0; j<32; j++) {\r
-                       if(BigBuf[i] & (1 << j)) {\r
-                               dest[--n] = 1;\r
-                       } else {\r
-                               dest[--n] = -1;\r
-                       }\r
-               }\r
-       }\r
-}\r
-\r
-// arguments: 64bit data split into 32bit idhi:idlo and optional 16bit crc\r
-// if crc provided, it will be written with the data verbatim (even if bogus)\r
-// if not provided a valid crc will be computed from the data and written.\r
-void WriteTItag(DWORD idhi, DWORD idlo, WORD crc)\r
-{\r
-\r
-       // WARNING the order of the bytes in which we calc crc below needs checking\r
-       // i'm 99% sure the crc algorithm is correct, but it may need to eat the\r
-       // bytes in reverse or something\r
-\r
-       if(crc == 0) {\r
-               crc = update_crc16(crc, (idlo)&0xff);\r
-               crc = update_crc16(crc, (idlo>>8)&0xff);\r
-               crc = update_crc16(crc, (idlo>>16)&0xff);\r
-               crc = update_crc16(crc, (idlo>>24)&0xff);\r
-               crc = update_crc16(crc, (idhi)&0xff);\r
-               crc = update_crc16(crc, (idhi>>8)&0xff);\r
-               crc = update_crc16(crc, (idhi>>16)&0xff);\r
-               crc = update_crc16(crc, (idhi>>24)&0xff);\r
-       }\r
-       DbpString("Writing the following data to tag:");\r
-       DbpIntegers(idhi, idlo, crc);\r
-\r
-       // TI tags charge at 134.2Khz\r
-       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz\r
-       // Place FPGA in passthrough mode, in this mode the CROSS_LO line\r
-       // connects to SSP_DIN and the SSP_DOUT logic level controls\r
-       // whether we're modulating the antenna (high)\r
-       // or listening to the antenna (low)\r
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);\r
-       LED_A_ON();\r
-\r
-       // steal this pin from the SSP and use it to control the modulation\r
-  PIO_ENABLE = (1<<GPIO_SSC_DOUT);\r
-       PIO_OUTPUT_ENABLE       = (1<<GPIO_SSC_DOUT);\r
-\r
-       // writing algorithm:\r
-       // a high bit consists of a field off for 1ms and field on for 1ms\r
-       // a low bit consists of a field off for 0.3ms and field on for 1.7ms\r
-       // initiate a charge time of 50ms (field on) then immediately start writing bits\r
-       // start by writing 0xBB (keyword) and 0xEB (password)\r
-       // then write 80 bits of data (or 64 bit data + 16 bit crc if you prefer)\r
-       // finally end with 0x0300 (write frame)\r
-       // all data is sent lsb firts\r
-       // finish with 15ms programming time\r
-\r
-       // modulate antenna\r
-       PIO_OUTPUT_DATA_SET = (1<<GPIO_SSC_DOUT);\r
-       SpinDelay(50);  // charge time\r
-\r
-       WriteTIbyte(0xbb); // keyword\r
-       WriteTIbyte(0xeb); // password\r
-       WriteTIbyte( (idlo    )&0xff );\r
-       WriteTIbyte( (idlo>>8 )&0xff );\r
-       WriteTIbyte( (idlo>>16)&0xff );\r
-       WriteTIbyte( (idlo>>24)&0xff );\r
-       WriteTIbyte( (idhi    )&0xff );\r
-       WriteTIbyte( (idhi>>8 )&0xff );\r
-       WriteTIbyte( (idhi>>16)&0xff );\r
-       WriteTIbyte( (idhi>>24)&0xff ); // data hi to lo\r
-       WriteTIbyte( (crc     )&0xff ); // crc lo\r
-       WriteTIbyte( (crc>>8  )&0xff ); // crc hi\r
-       WriteTIbyte(0x00); // write frame lo\r
-       WriteTIbyte(0x03); // write frame hi\r
-       PIO_OUTPUT_DATA_SET = (1<<GPIO_SSC_DOUT);\r
-       SpinDelay(50);  // programming time\r
-\r
-       LED_A_OFF();\r
-\r
-       // get TI tag data into the buffer\r
-       AcquireTiType();\r
-\r
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);\r
-       DbpString("Now use tiread to check");\r
-}\r
-\r
-void SimulateTagLowFrequency(int period, int ledcontrol)\r
-{\r
-       int i;\r
-       BYTE *tab = (BYTE *)BigBuf;\r
-\r
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);\r
-\r
-       PIO_ENABLE = (1 << GPIO_SSC_DOUT) | (1 << GPIO_SSC_CLK);\r
-\r
-       PIO_OUTPUT_ENABLE = (1 << GPIO_SSC_DOUT);\r
-       PIO_OUTPUT_DISABLE = (1 << GPIO_SSC_CLK);\r
-\r
-#define SHORT_COIL()   LOW(GPIO_SSC_DOUT)\r
-#define OPEN_COIL()    HIGH(GPIO_SSC_DOUT)\r
-\r
-       i = 0;\r
-       for(;;) {\r
-               while(!(PIO_PIN_DATA_STATUS & (1<<GPIO_SSC_CLK))) {\r
-                       if(BUTTON_PRESS()) {\r
-                               DbpString("Stopped");\r
-                               return;\r
-                       }\r
-                       WDT_HIT();\r
-               }\r
-\r
-               if (ledcontrol)\r
-                       LED_D_ON();\r
-\r
-               if(tab[i])\r
-                       OPEN_COIL();\r
-               else\r
-                       SHORT_COIL();\r
-\r
-               if (ledcontrol)\r
-                       LED_D_OFF();\r
-\r
-               while(PIO_PIN_DATA_STATUS & (1<<GPIO_SSC_CLK)) {\r
-                       if(BUTTON_PRESS()) {\r
-                               DbpString("Stopped");\r
-                               return;\r
-                       }\r
-                       WDT_HIT();\r
-               }\r
-\r
-               i++;\r
-               if(i == period) i = 0;\r
-       }\r
-}\r
-\r
-// compose fc/8 fc/10 waveform\r
-static void fc(int c, int *n) {\r
-       BYTE *dest = (BYTE *)BigBuf;\r
-       int idx;\r
-\r
-       // for when we want an fc8 pattern every 4 logical bits\r
-       if(c==0) {\r
-               dest[((*n)++)]=1;\r
-               dest[((*n)++)]=1;\r
-               dest[((*n)++)]=0;\r
-               dest[((*n)++)]=0;\r
-               dest[((*n)++)]=0;\r
-               dest[((*n)++)]=0;\r
-               dest[((*n)++)]=0;\r
-               dest[((*n)++)]=0;\r
-       }\r
-       //      an fc/8  encoded bit is a bit pattern of  11000000  x6 = 48 samples\r
-       if(c==8) {\r
-               for (idx=0; idx<6; idx++) {\r
-                       dest[((*n)++)]=1;\r
-                       dest[((*n)++)]=1;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-               }\r
-       }\r
-\r
-       //      an fc/10 encoded bit is a bit pattern of 1110000000 x5 = 50 samples\r
-       if(c==10) {\r
-               for (idx=0; idx<5; idx++) {\r
-                       dest[((*n)++)]=1;\r
-                       dest[((*n)++)]=1;\r
-                       dest[((*n)++)]=1;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-                       dest[((*n)++)]=0;\r
-               }\r
-       }\r
-}\r
-\r
-// prepare a waveform pattern in the buffer based on the ID given then\r
-// simulate a HID tag until the button is pressed\r
-void CmdHIDsimTAG(int hi, int lo, int ledcontrol)\r
-{\r
-       int n=0, i=0;\r
-       /*\r
-        HID tag bitstream format\r
-        The tag contains a 44bit unique code. This is sent out MSB first in sets of 4 bits\r
-        A 1 bit is represented as 6 fc8 and 5 fc10 patterns\r
-        A 0 bit is represented as 5 fc10 and 6 fc8 patterns\r
-        A fc8 is inserted before every 4 bits\r
-        A special start of frame pattern is used consisting a0b0 where a and b are neither 0\r
-        nor 1 bits, they are special patterns (a = set of 12 fc8 and b = set of 10 fc10)\r
-       */\r
-\r
-       if (hi>0xFFF) {\r
-               DbpString("Tags can only have 44 bits.");\r
-               return;\r
-       }\r
-       fc(0,&n);\r
-       // special start of frame marker containing invalid bit sequences\r
-       fc(8,  &n);     fc(8,  &n);     // invalid\r
-       fc(8,  &n);     fc(10, &n); // logical 0\r
-       fc(10, &n);     fc(10, &n); // invalid\r
-       fc(8,  &n);     fc(10, &n); // logical 0\r
-\r
-       WDT_HIT();\r
-       // manchester encode bits 43 to 32\r
-       for (i=11; i>=0; i--) {\r
-               if ((i%4)==3) fc(0,&n);\r
-               if ((hi>>i)&1) {\r
-                       fc(10, &n);     fc(8,  &n);             // low-high transition\r
-               } else {\r
-                       fc(8,  &n);     fc(10, &n);             // high-low transition\r
-               }\r
-       }\r
-\r
-       WDT_HIT();\r
-       // manchester encode bits 31 to 0\r
-       for (i=31; i>=0; i--) {\r
-               if ((i%4)==3) fc(0,&n);\r
-               if ((lo>>i)&1) {\r
-                       fc(10, &n);     fc(8,  &n);             // low-high transition\r
-               } else {\r
-                       fc(8,  &n);     fc(10, &n);             // high-low transition\r
-               }\r
-       }\r
-\r
-       if (ledcontrol)\r
-               LED_A_ON();\r
-       SimulateTagLowFrequency(n, ledcontrol);\r
-\r
-       if (ledcontrol)\r
-               LED_A_OFF();\r
-}\r
-\r
-\r
-// loop to capture raw HID waveform then FSK demodulate the TAG ID from it\r
-void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)\r
-{\r
-       BYTE *dest = (BYTE *)BigBuf;\r
-       int m=0, n=0, i=0, idx=0, found=0, lastval=0;\r
-       DWORD hi=0, lo=0;\r
-\r
-       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz\r
-       FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);\r
-\r
-       // Connect the A/D to the peak-detected low-frequency path.\r
-       SetAdcMuxFor(GPIO_MUXSEL_LOPKD);\r
-\r
-       // Give it a bit of time for the resonant antenna to settle.\r
-       SpinDelay(50);\r
-\r
-       // Now set up the SSC to get the ADC samples that are now streaming at us.\r
-       FpgaSetupSsc();\r
-\r
-       for(;;) {\r
-               WDT_HIT();\r
-               if (ledcontrol)\r
-                       LED_A_ON();\r
-               if(BUTTON_PRESS()) {\r
-                       DbpString("Stopped");\r
-                       if (ledcontrol)\r
-                               LED_A_OFF();\r
-                       return;\r
-               }\r
-\r
-               i = 0;\r
-               m = sizeof(BigBuf);\r
-               memset(dest,128,m);\r
-               for(;;) {\r
-                       if(SSC_STATUS & (SSC_STATUS_TX_READY)) {\r
-                               SSC_TRANSMIT_HOLDING = 0x43;\r
-                               if (ledcontrol)\r
-                                       LED_D_ON();\r
-                       }\r
-                       if(SSC_STATUS & (SSC_STATUS_RX_READY)) {\r
-                               dest[i] = (BYTE)SSC_RECEIVE_HOLDING;\r
-                               // we don't care about actual value, only if it's more or less than a\r
-                               // threshold essentially we capture zero crossings for later analysis\r
-                               if(dest[i] < 127) dest[i] = 0; else dest[i] = 1;\r
-                               i++;\r
-                               if (ledcontrol)\r
-                                       LED_D_OFF();\r
-                               if(i >= m) {\r
-                                       break;\r
-                               }\r
-                       }\r
-               }\r
-\r
-               // FSK demodulator\r
-\r
-               // sync to first lo-hi transition\r
-               for( idx=1; idx<m; idx++) {\r
-                       if (dest[idx-1]<dest[idx])\r
-                               lastval=idx;\r
-                               break;\r
-               }\r
-               WDT_HIT();\r
-\r
-               // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)\r
-               // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere\r
-               // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10\r
-               for( i=0; idx<m; idx++) {\r
-                       if (dest[idx-1]<dest[idx]) {\r
-                               dest[i]=idx-lastval;\r
-                               if (dest[i] <= 8) {\r
-                                               dest[i]=1;\r
-                               } else {\r
-                                               dest[i]=0;\r
-                               }\r
-\r
-                               lastval=idx;\r
-                               i++;\r
-                       }\r
-               }\r
-               m=i;\r
-               WDT_HIT();\r
-\r
-               // we now have a set of cycle counts, loop over previous results and aggregate data into bit patterns\r
-               lastval=dest[0];\r
-               idx=0;\r
-               i=0;\r
-               n=0;\r
-               for( idx=0; idx<m; idx++) {\r
-                       if (dest[idx]==lastval) {\r
-                               n++;\r
-                       } else {\r
-                               // a bit time is five fc/10 or six fc/8 cycles so figure out how many bits a pattern width represents,\r
-                               // an extra fc/8 pattern preceeds every 4 bits (about 200 cycles) just to complicate things but it gets\r
-                               // swallowed up by rounding\r
-                               // expected results are 1 or 2 bits, any more and it's an invalid manchester encoding\r
-                               // special start of frame markers use invalid manchester states (no transitions) by using sequences\r
-                               // like 111000\r
-                               if (dest[idx-1]) {\r
-                                       n=(n+1)/6;                      // fc/8 in sets of 6\r
-                               } else {\r
-                                       n=(n+1)/5;                      // fc/10 in sets of 5\r
-                               }\r
-                               switch (n) {                    // stuff appropriate bits in buffer\r
-                                       case 0:\r
-                                       case 1: // one bit\r
-                                               dest[i++]=dest[idx-1];\r
-                                               break;\r
-                                       case 2: // two bits\r
-                                               dest[i++]=dest[idx-1];\r
-                                               dest[i++]=dest[idx-1];\r
-                                               break;\r
-                                       case 3: // 3 bit start of frame markers\r
-                                               dest[i++]=dest[idx-1];\r
-                                               dest[i++]=dest[idx-1];\r
-                                               dest[i++]=dest[idx-1];\r
-                                               break;\r
-                                       // When a logic 0 is immediately followed by the start of the next transmisson\r
-                                       // (special pattern) a pattern of 4 bit duration lengths is created.\r
-                                       case 4:\r
-                                               dest[i++]=dest[idx-1];\r
-                                               dest[i++]=dest[idx-1];\r
-                                               dest[i++]=dest[idx-1];\r
-                                               dest[i++]=dest[idx-1];\r
-                                               break;\r
-                                       default:        // this shouldn't happen, don't stuff any bits\r
-                                               break;\r
-                               }\r
-                               n=0;\r
-                               lastval=dest[idx];\r
-                       }\r
-               }\r
-               m=i;\r
-               WDT_HIT();\r
-\r
-               // final loop, go over previously decoded manchester data and decode into usable tag ID\r
-               // 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0\r
-               for( idx=0; idx<m-6; idx++) {\r
-                       // search for a start of frame marker\r
-                       if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )\r
-                       {\r
-                               found=1;\r
-                               idx+=6;\r
-                               if (found && (hi|lo)) {\r
-                                       DbpString("TAG ID");\r
-                                       DbpIntegers(hi, lo, (lo>>1)&0xffff);\r
-                                       /* if we're only looking for one tag */\r
-                                       if (findone)\r
-                                       {\r
-                                               *high = hi;\r
-                                               *low = lo;\r
-                                               return;\r
-                                       }\r
-                                       hi=0;\r
-                                       lo=0;\r
-                                       found=0;\r
-                               }\r
-                       }\r
-                       if (found) {\r
-                               if (dest[idx] && (!dest[idx+1]) ) {\r
-                                       hi=(hi<<1)|(lo>>31);\r
-                                       lo=(lo<<1)|0;\r
-                               } else if ( (!dest[idx]) && dest[idx+1]) {\r
-                                       hi=(hi<<1)|(lo>>31);\r
-                                       lo=(lo<<1)|1;\r
-                               } else {\r
-                                       found=0;\r
-                                       hi=0;\r
-                                       lo=0;\r
-                               }\r
-                               idx++;\r
-                       }\r
-                       if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )\r
-                       {\r
-                               found=1;\r
-                               idx+=6;\r
-                               if (found && (hi|lo)) {\r
-                                       DbpString("TAG ID");\r
-                                       DbpIntegers(hi, lo, (lo>>1)&0xffff);\r
-                                       /* if we're only looking for one tag */\r
-                                       if (findone)\r
-                                       {\r
-                                               *high = hi;\r
-                                               *low = lo;\r
-                                               return;\r
-                                       }\r
-                                       hi=0;\r
-                                       lo=0;\r
-                                       found=0;\r
-                               }\r
-                       }\r
-               }\r
-               WDT_HIT();\r
-       }\r
-}\r
+//-----------------------------------------------------------------------------
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Miscellaneous routines for low frequency tag operations.
+// Tags supported here so far are Texas Instruments (TI), HID
+// Also routines for raw mode reading/simulating of LF waveform
+//-----------------------------------------------------------------------------
+
+#include "proxmark3.h"
+#include "apps.h"
+#include "util.h"
+#include "hitag2.h"
+#include "crc16.h"
+#include "string.h"
+#include "lfdemod.h"
+#include "lfsampling.h"
+
+
+/**
+ * Function to do a modulation and then get samples.
+ * @param delay_off
+ * @param period_0
+ * @param period_1
+ * @param command
+ */
+void ModThenAcquireRawAdcSamples125k(int delay_off, int period_0, int period_1, uint8_t *command)
+{
+
+    int divisor_used = 95; // 125 KHz
+    // see if 'h' was specified
+
+    if (command[strlen((char *) command) - 1] == 'h')
+        divisor_used = 88; // 134.8 KHz
+
+       sample_config sc = { 0,0,1, divisor_used, 0};
+       setSamplingConfig(&sc);
+
+       /* Make sure the tag is reset */
+       FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+       FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+       SpinDelay(2500);
+
+       LFSetupFPGAForADC(sc.divisor, 1);
+
+       // And a little more time for the tag to fully power up
+       SpinDelay(2000);
+
+    // now modulate the reader field
+    while(*command != '\0' && *command != ' ') {
+        FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+        LED_D_OFF();
+        SpinDelayUs(delay_off);
+               FpgaSendCommand(FPGA_CMD_SET_DIVISOR, sc.divisor);
+
+        FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+        LED_D_ON();
+        if(*(command++) == '0')
+            SpinDelayUs(period_0);
+        else
+            SpinDelayUs(period_1);
+    }
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    LED_D_OFF();
+    SpinDelayUs(delay_off);
+       FpgaSendCommand(FPGA_CMD_SET_DIVISOR, sc.divisor);
+
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+
+    // now do the read
+       DoAcquisition_config(false);
+}
+
+
+
+/* blank r/w tag data stream
+...0000000000000000 01111111
+1010101010101010101010101010101010101010101010101010101010101010
+0011010010100001
+01111111
+101010101010101[0]000...
+
+[5555fe852c5555555555555555fe0000]
+*/
+void ReadTItag(void)
+{
+    // some hardcoded initial params
+    // when we read a TI tag we sample the zerocross line at 2Mhz
+    // TI tags modulate a 1 as 16 cycles of 123.2Khz
+    // TI tags modulate a 0 as 16 cycles of 134.2Khz
+ #define FSAMPLE 2000000
+ #define FREQLO 123200
+ #define FREQHI 134200
+
+    signed char *dest = (signed char *)BigBuf;
+    int n = sizeof(BigBuf);
+    // 128 bit shift register [shift3:shift2:shift1:shift0]
+    uint32_t shift3 = 0, shift2 = 0, shift1 = 0, shift0 = 0;
+
+    int i, cycles=0, samples=0;
+    // how many sample points fit in 16 cycles of each frequency
+    uint32_t sampleslo = (FSAMPLE<<4)/FREQLO, sampleshi = (FSAMPLE<<4)/FREQHI;
+    // when to tell if we're close enough to one freq or another
+    uint32_t threshold = (sampleslo - sampleshi + 1)>>1;
+
+    // TI tags charge at 134.2Khz
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+
+    // Place FPGA in passthrough mode, in this mode the CROSS_LO line
+    // connects to SSP_DIN and the SSP_DOUT logic level controls
+    // whether we're modulating the antenna (high)
+    // or listening to the antenna (low)
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
+
+    // get TI tag data into the buffer
+    AcquireTiType();
+
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+
+    for (i=0; i<n-1; i++) {
+        // count cycles by looking for lo to hi zero crossings
+        if ( (dest[i]<0) && (dest[i+1]>0) ) {
+            cycles++;
+            // after 16 cycles, measure the frequency
+            if (cycles>15) {
+                cycles=0;
+                samples=i-samples; // number of samples in these 16 cycles
+
+                // TI bits are coming to us lsb first so shift them
+                // right through our 128 bit right shift register
+                shift0 = (shift0>>1) | (shift1 << 31);
+                shift1 = (shift1>>1) | (shift2 << 31);
+                shift2 = (shift2>>1) | (shift3 << 31);
+                shift3 >>= 1;
+
+                // check if the cycles fall close to the number
+                // expected for either the low or high frequency
+                if ( (samples>(sampleslo-threshold)) && (samples<(sampleslo+threshold)) ) {
+                    // low frequency represents a 1
+                    shift3 |= (1<<31);
+                } else if ( (samples>(sampleshi-threshold)) && (samples<(sampleshi+threshold)) ) {
+                    // high frequency represents a 0
+                } else {
+                    // probably detected a gay waveform or noise
+                    // use this as gaydar or discard shift register and start again
+                    shift3 = shift2 = shift1 = shift0 = 0;
+                }
+                samples = i;
+
+                // for each bit we receive, test if we've detected a valid tag
+
+                // if we see 17 zeroes followed by 6 ones, we might have a tag
+                // remember the bits are backwards
+                if ( ((shift0 & 0x7fffff) == 0x7e0000) ) {
+                    // if start and end bytes match, we have a tag so break out of the loop
+                    if ( ((shift0>>16)&0xff) == ((shift3>>8)&0xff) ) {
+                        cycles = 0xF0B; //use this as a flag (ugly but whatever)
+                        break;
+                    }
+                }
+            }
+        }
+    }
+
+    // if flag is set we have a tag
+    if (cycles!=0xF0B) {
+        DbpString("Info: No valid tag detected.");
+    } else {
+        // put 64 bit data into shift1 and shift0
+        shift0 = (shift0>>24) | (shift1 << 8);
+        shift1 = (shift1>>24) | (shift2 << 8);
+
+        // align 16 bit crc into lower half of shift2
+        shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;
+
+        // if r/w tag, check ident match
+               if (shift3 & (1<<15) ) {
+            DbpString("Info: TI tag is rewriteable");
+            // only 15 bits compare, last bit of ident is not valid
+                       if (((shift3 >> 16) ^ shift0) & 0x7fff ) {
+                DbpString("Error: Ident mismatch!");
+            } else {
+                DbpString("Info: TI tag ident is valid");
+            }
+        } else {
+            DbpString("Info: TI tag is readonly");
+        }
+
+        // WARNING the order of the bytes in which we calc crc below needs checking
+        // i'm 99% sure the crc algorithm is correct, but it may need to eat the
+        // bytes in reverse or something
+        // calculate CRC
+        uint32_t crc=0;
+
+        crc = update_crc16(crc, (shift0)&0xff);
+        crc = update_crc16(crc, (shift0>>8)&0xff);
+        crc = update_crc16(crc, (shift0>>16)&0xff);
+        crc = update_crc16(crc, (shift0>>24)&0xff);
+        crc = update_crc16(crc, (shift1)&0xff);
+        crc = update_crc16(crc, (shift1>>8)&0xff);
+        crc = update_crc16(crc, (shift1>>16)&0xff);
+        crc = update_crc16(crc, (shift1>>24)&0xff);
+
+        Dbprintf("Info: Tag data: %x%08x, crc=%x",
+                 (unsigned int)shift1, (unsigned int)shift0, (unsigned int)shift2 & 0xFFFF);
+        if (crc != (shift2&0xffff)) {
+            Dbprintf("Error: CRC mismatch, expected %x", (unsigned int)crc);
+        } else {
+            DbpString("Info: CRC is good");
+        }
+    }
+}
+
+void WriteTIbyte(uint8_t b)
+{
+    int i = 0;
+
+    // modulate 8 bits out to the antenna
+    for (i=0; i<8; i++)
+    {
+        if (b&(1<<i)) {
+            // stop modulating antenna
+            LOW(GPIO_SSC_DOUT);
+            SpinDelayUs(1000);
+            // modulate antenna
+            HIGH(GPIO_SSC_DOUT);
+            SpinDelayUs(1000);
+        } else {
+            // stop modulating antenna
+            LOW(GPIO_SSC_DOUT);
+            SpinDelayUs(300);
+            // modulate antenna
+            HIGH(GPIO_SSC_DOUT);
+            SpinDelayUs(1700);
+        }
+    }
+}
+
+void AcquireTiType(void)
+{
+    int i, j, n;
+    // tag transmission is <20ms, sampling at 2M gives us 40K samples max
+    // each sample is 1 bit stuffed into a uint32_t so we need 1250 uint32_t
+ #define TIBUFLEN 1250
+
+    // clear buffer
+    memset(BigBuf,0,sizeof(BigBuf));
+
+    // Set up the synchronous serial port
+    AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DIN;
+    AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN;
+
+    // steal this pin from the SSP and use it to control the modulation
+    AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+    AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+
+    AT91C_BASE_SSC->SSC_CR = AT91C_SSC_SWRST;
+    AT91C_BASE_SSC->SSC_CR = AT91C_SSC_RXEN | AT91C_SSC_TXEN;
+
+    // Sample at 2 Mbit/s, so TI tags are 16.2 vs. 14.9 clocks long
+    // 48/2 = 24 MHz clock must be divided by 12
+    AT91C_BASE_SSC->SSC_CMR = 12;
+
+    AT91C_BASE_SSC->SSC_RCMR = SSC_CLOCK_MODE_SELECT(0);
+    AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(32) | AT91C_SSC_MSBF;
+    AT91C_BASE_SSC->SSC_TCMR = 0;
+    AT91C_BASE_SSC->SSC_TFMR = 0;
+
+    LED_D_ON();
+
+    // modulate antenna
+    HIGH(GPIO_SSC_DOUT);
+
+    // Charge TI tag for 50ms.
+    SpinDelay(50);
+
+    // stop modulating antenna and listen
+    LOW(GPIO_SSC_DOUT);
+
+    LED_D_OFF();
+
+    i = 0;
+    for(;;) {
+        if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+            BigBuf[i] = AT91C_BASE_SSC->SSC_RHR;       // store 32 bit values in buffer
+            i++; if(i >= TIBUFLEN) break;
+        }
+        WDT_HIT();
+    }
+
+    // return stolen pin to SSP
+    AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DOUT;
+    AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN | GPIO_SSC_DOUT;
+
+    char *dest = (char *)BigBuf;
+    n = TIBUFLEN*32;
+    // unpack buffer
+    for (i=TIBUFLEN-1; i>=0; i--) {
+        for (j=0; j<32; j++) {
+            if(BigBuf[i] & (1 << j)) {
+                dest[--n] = 1;
+            } else {
+                dest[--n] = -1;
+            }
+        }
+    }
+}
+
+// arguments: 64bit data split into 32bit idhi:idlo and optional 16bit crc
+// if crc provided, it will be written with the data verbatim (even if bogus)
+// if not provided a valid crc will be computed from the data and written.
+void WriteTItag(uint32_t idhi, uint32_t idlo, uint16_t crc)
+{
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    if(crc == 0) {
+        crc = update_crc16(crc, (idlo)&0xff);
+        crc = update_crc16(crc, (idlo>>8)&0xff);
+        crc = update_crc16(crc, (idlo>>16)&0xff);
+        crc = update_crc16(crc, (idlo>>24)&0xff);
+        crc = update_crc16(crc, (idhi)&0xff);
+        crc = update_crc16(crc, (idhi>>8)&0xff);
+        crc = update_crc16(crc, (idhi>>16)&0xff);
+        crc = update_crc16(crc, (idhi>>24)&0xff);
+    }
+    Dbprintf("Writing to tag: %x%08x, crc=%x",
+             (unsigned int) idhi, (unsigned int) idlo, crc);
+
+    // TI tags charge at 134.2Khz
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+    // Place FPGA in passthrough mode, in this mode the CROSS_LO line
+    // connects to SSP_DIN and the SSP_DOUT logic level controls
+    // whether we're modulating the antenna (high)
+    // or listening to the antenna (low)
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
+    LED_A_ON();
+
+    // steal this pin from the SSP and use it to control the modulation
+    AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+    AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+
+    // writing algorithm:
+    // a high bit consists of a field off for 1ms and field on for 1ms
+    // a low bit consists of a field off for 0.3ms and field on for 1.7ms
+    // initiate a charge time of 50ms (field on) then immediately start writing bits
+    // start by writing 0xBB (keyword) and 0xEB (password)
+    // then write 80 bits of data (or 64 bit data + 16 bit crc if you prefer)
+    // finally end with 0x0300 (write frame)
+    // all data is sent lsb firts
+    // finish with 15ms programming time
+
+    // modulate antenna
+    HIGH(GPIO_SSC_DOUT);
+    SpinDelay(50);     // charge time
+
+    WriteTIbyte(0xbb); // keyword
+    WriteTIbyte(0xeb); // password
+    WriteTIbyte( (idlo    )&0xff );
+    WriteTIbyte( (idlo>>8 )&0xff );
+    WriteTIbyte( (idlo>>16)&0xff );
+    WriteTIbyte( (idlo>>24)&0xff );
+    WriteTIbyte( (idhi    )&0xff );
+    WriteTIbyte( (idhi>>8 )&0xff );
+    WriteTIbyte( (idhi>>16)&0xff );
+    WriteTIbyte( (idhi>>24)&0xff ); // data hi to lo
+    WriteTIbyte( (crc     )&0xff ); // crc lo
+    WriteTIbyte( (crc>>8  )&0xff ); // crc hi
+    WriteTIbyte(0x00); // write frame lo
+    WriteTIbyte(0x03); // write frame hi
+    HIGH(GPIO_SSC_DOUT);
+    SpinDelay(50);     // programming time
+
+    LED_A_OFF();
+
+    // get TI tag data into the buffer
+    AcquireTiType();
+
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    DbpString("Now use tiread to check");
+}
+
+void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
+{
+    int i;
+    uint8_t *tab = (uint8_t *)BigBuf;
+
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_EDGE_DETECT);
+
+    AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT | GPIO_SSC_CLK;
+
+    AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+    AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_CLK;
+
+#define SHORT_COIL()   LOW(GPIO_SSC_DOUT)
+#define OPEN_COIL()            HIGH(GPIO_SSC_DOUT)
+
+    i = 0;
+    for(;;) {
+        while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)) {
+            if(BUTTON_PRESS()) {
+                DbpString("Stopped");
+                return;
+            }
+            WDT_HIT();
+        }
+
+        if (ledcontrol)
+            LED_D_ON();
+
+        if(tab[i])
+            OPEN_COIL();
+        else
+            SHORT_COIL();
+
+        if (ledcontrol)
+            LED_D_OFF();
+
+        while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK) {
+            if(BUTTON_PRESS()) {
+                DbpString("Stopped");
+                return;
+            }
+            WDT_HIT();
+        }
+
+        i++;
+        if(i == period) {
+            i = 0;
+            if (gap) {
+                SHORT_COIL();
+                SpinDelayUs(gap);
+            }
+        }
+    }
+}
+
+#define DEBUG_FRAME_CONTENTS 1
+void SimulateTagLowFrequencyBidir(int divisor, int t0)
+{
+}
+
+// compose fc/8 fc/10 waveform
+static void fc(int c, int *n) {
+    uint8_t *dest = (uint8_t *)BigBuf;
+    int idx;
+
+    // for when we want an fc8 pattern every 4 logical bits
+    if(c==0) {
+        dest[((*n)++)]=1;
+        dest[((*n)++)]=1;
+        dest[((*n)++)]=0;
+        dest[((*n)++)]=0;
+        dest[((*n)++)]=0;
+        dest[((*n)++)]=0;
+        dest[((*n)++)]=0;
+        dest[((*n)++)]=0;
+    }
+    // an fc/8  encoded bit is a bit pattern of  11000000  x6 = 48 samples
+    if(c==8) {
+        for (idx=0; idx<6; idx++) {
+            dest[((*n)++)]=1;
+            dest[((*n)++)]=1;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+        }
+    }
+
+    // an fc/10 encoded bit is a bit pattern of 1110000000 x5 = 50 samples
+    if(c==10) {
+        for (idx=0; idx<5; idx++) {
+            dest[((*n)++)]=1;
+            dest[((*n)++)]=1;
+            dest[((*n)++)]=1;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+            dest[((*n)++)]=0;
+        }
+    }
+}
+
+// prepare a waveform pattern in the buffer based on the ID given then
+// simulate a HID tag until the button is pressed
+void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
+{
+    int n=0, i=0;
+    /*
+     HID tag bitstream format
+     The tag contains a 44bit unique code. This is sent out MSB first in sets of 4 bits
+     A 1 bit is represented as 6 fc8 and 5 fc10 patterns
+     A 0 bit is represented as 5 fc10 and 6 fc8 patterns
+     A fc8 is inserted before every 4 bits
+     A special start of frame pattern is used consisting a0b0 where a and b are neither 0
+     nor 1 bits, they are special patterns (a = set of 12 fc8 and b = set of 10 fc10)
+    */
+
+    if (hi>0xFFF) {
+        DbpString("Tags can only have 44 bits.");
+        return;
+    }
+    fc(0,&n);
+    // special start of frame marker containing invalid bit sequences
+    fc(8,  &n);        fc(8,  &n);     // invalid
+    fc(8,  &n);        fc(10, &n); // logical 0
+    fc(10, &n);        fc(10, &n); // invalid
+    fc(8,  &n);        fc(10, &n); // logical 0
+
+    WDT_HIT();
+    // manchester encode bits 43 to 32
+    for (i=11; i>=0; i--) {
+        if ((i%4)==3) fc(0,&n);
+        if ((hi>>i)&1) {
+            fc(10, &n);        fc(8,  &n);             // low-high transition
+        } else {
+            fc(8,  &n);        fc(10, &n);             // high-low transition
+        }
+    }
+
+    WDT_HIT();
+    // manchester encode bits 31 to 0
+    for (i=31; i>=0; i--) {
+        if ((i%4)==3) fc(0,&n);
+        if ((lo>>i)&1) {
+            fc(10, &n);        fc(8,  &n);             // low-high transition
+        } else {
+            fc(8,  &n);        fc(10, &n);             // high-low transition
+        }
+    }
+
+    if (ledcontrol)
+        LED_A_ON();
+    SimulateTagLowFrequency(n, 0, ledcontrol);
+
+    if (ledcontrol)
+        LED_A_OFF();
+}
+
+// loop to get raw HID waveform then FSK demodulate the TAG ID from it
+void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
+{
+    uint8_t *dest = (uint8_t *)BigBuf;
+
+    size_t size=0; //, found=0;
+    uint32_t hi2=0, hi=0, lo=0;
+
+    // Configure to go in 125Khz listen mode
+    LFSetupFPGAForADC(95, true);
+
+    while(!BUTTON_PRESS()) {
+
+        WDT_HIT();
+        if (ledcontrol) LED_A_ON();
+
+               DoAcquisition_default(-1,true);
+               // FSK demodulator
+               size = HIDdemodFSK(dest, sizeof(BigBuf), &hi2, &hi, &lo);
+
+        WDT_HIT();
+
+               if (size>0 && lo>0){
+            // final loop, go over previously decoded manchester data and decode into usable tag ID
+            // 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0
+            if (hi2 != 0){ //extra large HID tags
+                Dbprintf("TAG ID: %x%08x%08x (%d)",
+                         (unsigned int) hi2, (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
+            }else {  //standard HID tags <38 bits
+                //Dbprintf("TAG ID: %x%08x (%d)",(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF); //old print cmd
+                uint8_t bitlen = 0;
+                uint32_t fc = 0;
+                uint32_t cardnum = 0;
+                               if (((hi>>5)&1) == 1){//if bit 38 is set then < 37 bit format is used
+                    uint32_t lo2=0;
+                    lo2=(((hi & 31) << 12) | (lo>>20)); //get bits 21-37 to check for format len bit
+                    uint8_t idx3 = 1;
+                                       while(lo2 > 1){ //find last bit set to 1 (format len bit)
+                                               lo2=lo2 >> 1;
+                        idx3++;
+                    }
+                                       bitlen = idx3+19;
+                    fc =0;
+                    cardnum=0;
+                                       if(bitlen == 26){
+                        cardnum = (lo>>1)&0xFFFF;
+                        fc = (lo>>17)&0xFF;
+                    }
+                                       if(bitlen == 37){
+                        cardnum = (lo>>1)&0x7FFFF;
+                        fc = ((hi&0xF)<<12)|(lo>>20);
+                    }
+                                       if(bitlen == 34){
+                        cardnum = (lo>>1)&0xFFFF;
+                        fc= ((hi&1)<<15)|(lo>>17);
+                    }
+                                       if(bitlen == 35){
+                        cardnum = (lo>>1)&0xFFFFF;
+                        fc = ((hi&1)<<11)|(lo>>21);
+                    }
+                }
+                else { //if bit 38 is not set then 37 bit format is used
+                    bitlen= 37;
+                    fc =0;
+                    cardnum=0;
+                    if(bitlen==37){
+                        cardnum = (lo>>1)&0x7FFFF;
+                        fc = ((hi&0xF)<<12)|(lo>>20);
+                    }
+                }
+                //Dbprintf("TAG ID: %x%08x (%d)",
+                // (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
+                Dbprintf("TAG ID: %x%08x (%d) - Format Len: %dbit - FC: %d - Card: %d",
+                         (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF,
+                         (unsigned int) bitlen, (unsigned int) fc, (unsigned int) cardnum);
+            }
+            if (findone){
+                if (ledcontrol)        LED_A_OFF();
+                return;
+            }
+            // reset
+            hi2 = hi = lo = 0;
+        }
+        WDT_HIT();
+    }
+    DbpString("Stopped");
+    if (ledcontrol) LED_A_OFF();
+}
+
+void CmdEM410xdemod(int findone, int *high, int *low, int ledcontrol)
+{
+    uint8_t *dest = (uint8_t *)BigBuf;
+
+       size_t size=0;
+    int clk=0, invert=0, errCnt=0;
+    uint64_t lo=0;
+    // Configure to go in 125Khz listen mode
+    LFSetupFPGAForADC(95, true);
+
+    while(!BUTTON_PRESS()) {
+
+        WDT_HIT();
+        if (ledcontrol) LED_A_ON();
+
+               DoAcquisition_default(-1,true);
+               size  = sizeof(BigBuf);
+        //Dbprintf("DEBUG: Buffer got");
+               //askdemod and manchester decode
+               errCnt = askmandemod(dest, &size, &clk, &invert);
+        //Dbprintf("DEBUG: ASK Got");
+        WDT_HIT();
+
+        if (errCnt>=0){
+                       lo = Em410xDecode(dest,size);
+            //Dbprintf("DEBUG: EM GOT");
+            if (lo>0){
+                               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));
+            }
+            if (findone){
+                if (ledcontrol)        LED_A_OFF();
+                return;
+            }
+        } else{
+            //Dbprintf("DEBUG: No Tag");
+        }
+        WDT_HIT();
+        lo = 0;
+        clk=0;
+        invert=0;
+        errCnt=0;
+        size=0;
+    }
+    DbpString("Stopped");
+    if (ledcontrol) LED_A_OFF();
+}
+
+void CmdIOdemodFSK(int findone, int *high, int *low, int ledcontrol)
+{
+    uint8_t *dest = (uint8_t *)BigBuf;
+    int idx=0;
+    uint32_t code=0, code2=0;
+    uint8_t version=0;
+    uint8_t facilitycode=0;
+    uint16_t number=0;
+    // Configure to go in 125Khz listen mode
+    LFSetupFPGAForADC(95, true);
+
+    while(!BUTTON_PRESS()) {
+        WDT_HIT();
+        if (ledcontrol) LED_A_ON();
+               DoAcquisition_default(-1,true);
+               //fskdemod and get start index
+        WDT_HIT();
+        idx = IOdemodFSK(dest,sizeof(BigBuf));
+        if (idx>0){
+            //valid tag found
+
+            //Index map
+            //0           10          20          30          40          50          60
+            //|           |           |           |           |           |           |
+            //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
+            //-----------------------------------------------------------------------------
+            //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
+            //
+            //XSF(version)facility:codeone+codetwo
+            //Handle the data
+            if(findone){ //only print binary if we are doing one
+                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]);
+                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]);
+                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]);
+                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]);
+                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]);
+                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]);
+                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]);
+            }
+            code = bytebits_to_byte(dest+idx,32);
+            code2 = bytebits_to_byte(dest+idx+32,32);
+            version = bytebits_to_byte(dest+idx+27,8); //14,4
+            facilitycode = bytebits_to_byte(dest+idx+18,8) ;
+            number = (bytebits_to_byte(dest+idx+36,8)<<8)|(bytebits_to_byte(dest+idx+45,8)); //36,9
+
+            Dbprintf("XSF(%02d)%02x:%05d (%08x%08x)",version,facilitycode,number,code,code2);
+            // if we're only looking for one tag
+            if (findone){
+                if (ledcontrol)        LED_A_OFF();
+                //LED_A_OFF();
+                return;
+            }
+            code=code2=0;
+            version=facilitycode=0;
+            number=0;
+            idx=0;
+        }
+        WDT_HIT();
+    }
+    DbpString("Stopped");
+    if (ledcontrol) LED_A_OFF();
+}
+
+/*------------------------------
+ * T5555/T5557/T5567 routines
+ *------------------------------
+ */
+
+/* T55x7 configuration register definitions */
+#define T55x7_POR_DELAY                        0x00000001
+#define T55x7_ST_TERMINATOR            0x00000008
+#define T55x7_PWD                      0x00000010
+#define T55x7_MAXBLOCK_SHIFT           5
+#define T55x7_AOR                      0x00000200
+#define T55x7_PSKCF_RF_2               0
+#define T55x7_PSKCF_RF_4               0x00000400
+#define T55x7_PSKCF_RF_8               0x00000800
+#define T55x7_MODULATION_DIRECT                0
+#define T55x7_MODULATION_PSK1          0x00001000
+#define T55x7_MODULATION_PSK2          0x00002000
+#define T55x7_MODULATION_PSK3          0x00003000
+#define T55x7_MODULATION_FSK1          0x00004000
+#define T55x7_MODULATION_FSK2          0x00005000
+#define T55x7_MODULATION_FSK1a         0x00006000
+#define T55x7_MODULATION_FSK2a         0x00007000
+#define T55x7_MODULATION_MANCHESTER    0x00008000
+#define T55x7_MODULATION_BIPHASE       0x00010000
+#define T55x7_BITRATE_RF_8             0
+#define T55x7_BITRATE_RF_16            0x00040000
+#define T55x7_BITRATE_RF_32            0x00080000
+#define T55x7_BITRATE_RF_40            0x000C0000
+#define T55x7_BITRATE_RF_50            0x00100000
+#define T55x7_BITRATE_RF_64            0x00140000
+#define T55x7_BITRATE_RF_100           0x00180000
+#define T55x7_BITRATE_RF_128           0x001C0000
+
+/* T5555 (Q5) configuration register definitions */
+#define T5555_ST_TERMINATOR            0x00000001
+#define T5555_MAXBLOCK_SHIFT           0x00000001
+#define T5555_MODULATION_MANCHESTER    0
+#define T5555_MODULATION_PSK1          0x00000010
+#define T5555_MODULATION_PSK2          0x00000020
+#define T5555_MODULATION_PSK3          0x00000030
+#define T5555_MODULATION_FSK1          0x00000040
+#define T5555_MODULATION_FSK2          0x00000050
+#define T5555_MODULATION_BIPHASE       0x00000060
+#define T5555_MODULATION_DIRECT                0x00000070
+#define T5555_INVERT_OUTPUT            0x00000080
+#define T5555_PSK_RF_2                 0
+#define T5555_PSK_RF_4                 0x00000100
+#define T5555_PSK_RF_8                 0x00000200
+#define T5555_USE_PWD                  0x00000400
+#define T5555_USE_AOR                  0x00000800
+#define T5555_BITRATE_SHIFT            12
+#define T5555_FAST_WRITE               0x00004000
+#define T5555_PAGE_SELECT              0x00008000
+
+/*
+ * Relevant times in microsecond
+ * To compensate antenna falling times shorten the write times
+ * and enlarge the gap ones.
+ */
+#define START_GAP 250
+#define WRITE_GAP 160
+#define WRITE_0   144 // 192
+#define WRITE_1   400 // 432 for T55x7; 448 for E5550
+
+// Write one bit to card
+void T55xxWriteBit(int bit)
+{
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+    if (bit == 0)
+        SpinDelayUs(WRITE_0);
+    else
+        SpinDelayUs(WRITE_1);
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    SpinDelayUs(WRITE_GAP);
+}
+
+// Write one card block in page 0, no lock
+void T55xxWriteBlock(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t PwdMode)
+{
+    //unsigned int i;  //enio adjustment 12/10/14
+    uint32_t i;
+
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+
+    // Give it a bit of time for the resonant antenna to settle.
+    // And for the tag to fully power up
+    SpinDelay(150);
+
+    // Now start writting
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    SpinDelayUs(START_GAP);
+
+    // Opcode
+    T55xxWriteBit(1);
+    T55xxWriteBit(0); //Page 0
+    if (PwdMode == 1){
+        // Pwd
+        for (i = 0x80000000; i != 0; i >>= 1)
+            T55xxWriteBit(Pwd & i);
+    }
+    // Lock bit
+    T55xxWriteBit(0);
+
+    // Data
+    for (i = 0x80000000; i != 0; i >>= 1)
+        T55xxWriteBit(Data & i);
+
+    // Block
+    for (i = 0x04; i != 0; i >>= 1)
+        T55xxWriteBit(Block & i);
+
+    // Now perform write (nominal is 5.6 ms for T55x7 and 18ms for E5550,
+    // so wait a little more)
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+    SpinDelay(20);
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+}
+
+// Read one card block in page 0
+void T55xxReadBlock(uint32_t Block, uint32_t Pwd, uint8_t PwdMode)
+{
+    uint8_t *dest = (uint8_t *)BigBuf;
+    //int m=0, i=0; //enio adjustment 12/10/14
+    uint32_t m=0, i=0;
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    m = sizeof(BigBuf);
+    // Clear destination buffer before sending the command
+    memset(dest, 128, m);
+    // Connect the A/D to the peak-detected low-frequency path.
+    SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+    // Now set up the SSC to get the ADC samples that are now streaming at us.
+    FpgaSetupSsc();
+
+    LED_D_ON();
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+
+    // Give it a bit of time for the resonant antenna to settle.
+    // And for the tag to fully power up
+    SpinDelay(150);
+
+    // Now start writting
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    SpinDelayUs(START_GAP);
+
+    // Opcode
+    T55xxWriteBit(1);
+    T55xxWriteBit(0); //Page 0
+    if (PwdMode == 1){
+        // Pwd
+        for (i = 0x80000000; i != 0; i >>= 1)
+            T55xxWriteBit(Pwd & i);
+    }
+    // Lock bit
+    T55xxWriteBit(0);
+    // Block
+    for (i = 0x04; i != 0; i >>= 1)
+        T55xxWriteBit(Block & i);
+
+    // Turn field on to read the response
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+
+    // Now do the acquisition
+    i = 0;
+    for(;;) {
+        if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+            AT91C_BASE_SSC->SSC_THR = 0x43;
+        }
+        if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+            dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+            // we don't care about actual value, only if it's more or less than a
+            // threshold essentially we capture zero crossings for later analysis
+            //                 if(dest[i] < 127) dest[i] = 0; else dest[i] = 1;
+            i++;
+            if (i >= m) break;
+        }
+    }
+
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
+    LED_D_OFF();
+    DbpString("DONE!");
+}
+
+// Read card traceability data (page 1)
+void T55xxReadTrace(void){
+    uint8_t *dest = (uint8_t *)BigBuf;
+    int m=0, i=0;
+
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    m = sizeof(BigBuf);
+    // Clear destination buffer before sending the command
+    memset(dest, 128, m);
+    // Connect the A/D to the peak-detected low-frequency path.
+    SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+    // Now set up the SSC to get the ADC samples that are now streaming at us.
+    FpgaSetupSsc();
+
+    LED_D_ON();
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+
+    // Give it a bit of time for the resonant antenna to settle.
+    // And for the tag to fully power up
+    SpinDelay(150);
+
+    // Now start writting
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+    SpinDelayUs(START_GAP);
+
+    // Opcode
+    T55xxWriteBit(1);
+    T55xxWriteBit(1); //Page 1
+
+    // Turn field on to read the response
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+
+    // Now do the acquisition
+    i = 0;
+    for(;;) {
+        if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+            AT91C_BASE_SSC->SSC_THR = 0x43;
+        }
+        if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+            dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+            i++;
+            if (i >= m) break;
+        }
+    }
+
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
+    LED_D_OFF();
+    DbpString("DONE!");
+}
+
+/*-------------- Cloning routines -----------*/
+// Copy HID id to card and setup block 0 config
+void CopyHIDtoT55x7(uint32_t hi2, uint32_t hi, uint32_t lo, uint8_t longFMT)
+{
+    int data1=0, data2=0, data3=0, data4=0, data5=0, data6=0; //up to six blocks for long format
+    int last_block = 0;
+
+    if (longFMT){
+        // Ensure no more than 84 bits supplied
+        if (hi2>0xFFFFF) {
+            DbpString("Tags can only have 84 bits.");
+            return;
+        }
+        // Build the 6 data blocks for supplied 84bit ID
+        last_block = 6;
+        data1 = 0x1D96A900; // load preamble (1D) & long format identifier (9E manchester encoded)
+        for (int i=0;i<4;i++) {
+            if (hi2 & (1<<(19-i)))
+                data1 |= (1<<(((3-i)*2)+1)); // 1 -> 10
+            else
+                data1 |= (1<<((3-i)*2)); // 0 -> 01
+        }
+
+        data2 = 0;
+        for (int i=0;i<16;i++) {
+            if (hi2 & (1<<(15-i)))
+                data2 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+            else
+                data2 |= (1<<((15-i)*2)); // 0 -> 01
+        }
+
+        data3 = 0;
+        for (int i=0;i<16;i++) {
+            if (hi & (1<<(31-i)))
+                data3 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+            else
+                data3 |= (1<<((15-i)*2)); // 0 -> 01
+        }
+
+        data4 = 0;
+        for (int i=0;i<16;i++) {
+            if (hi & (1<<(15-i)))
+                data4 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+            else
+                data4 |= (1<<((15-i)*2)); // 0 -> 01
+        }
+
+        data5 = 0;
+        for (int i=0;i<16;i++) {
+            if (lo & (1<<(31-i)))
+                data5 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+            else
+                data5 |= (1<<((15-i)*2)); // 0 -> 01
+        }
+
+        data6 = 0;
+        for (int i=0;i<16;i++) {
+            if (lo & (1<<(15-i)))
+                data6 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+            else
+                data6 |= (1<<((15-i)*2)); // 0 -> 01
+        }
+    }
+    else {
+        // Ensure no more than 44 bits supplied
+        if (hi>0xFFF) {
+            DbpString("Tags can only have 44 bits.");
+            return;
+        }
+
+        // Build the 3 data blocks for supplied 44bit ID
+        last_block = 3;
+
+        data1 = 0x1D000000; // load preamble
+
+        for (int i=0;i<12;i++) {
+            if (hi & (1<<(11-i)))
+                data1 |= (1<<(((11-i)*2)+1)); // 1 -> 10
+            else
+                data1 |= (1<<((11-i)*2)); // 0 -> 01
+        }
+
+        data2 = 0;
+        for (int i=0;i<16;i++) {
+            if (lo & (1<<(31-i)))
+                data2 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+            else
+                data2 |= (1<<((15-i)*2)); // 0 -> 01
+        }
+
+        data3 = 0;
+        for (int i=0;i<16;i++) {
+            if (lo & (1<<(15-i)))
+                data3 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+            else
+                data3 |= (1<<((15-i)*2)); // 0 -> 01
+        }
+    }
+
+    LED_D_ON();
+    // Program the data blocks for supplied ID
+    // and the block 0 for HID format
+    T55xxWriteBlock(data1,1,0,0);
+    T55xxWriteBlock(data2,2,0,0);
+    T55xxWriteBlock(data3,3,0,0);
+
+    if (longFMT) { // if long format there are 6 blocks
+        T55xxWriteBlock(data4,4,0,0);
+        T55xxWriteBlock(data5,5,0,0);
+        T55xxWriteBlock(data6,6,0,0);
+    }
+
+    // Config for HID (RF/50, FSK2a, Maxblock=3 for short/6 for long)
+    T55xxWriteBlock(T55x7_BITRATE_RF_50    |
+                    T55x7_MODULATION_FSK2a |
+                    last_block << T55x7_MAXBLOCK_SHIFT,
+                    0,0,0);
+
+    LED_D_OFF();
+
+    DbpString("DONE!");
+}
+
+void CopyIOtoT55x7(uint32_t hi, uint32_t lo, uint8_t longFMT)
+{
+    int data1=0, data2=0; //up to six blocks for long format
+
+    data1 = hi;  // load preamble
+    data2 = lo;
+
+    LED_D_ON();
+    // Program the data blocks for supplied ID
+    // and the block 0 for HID format
+    T55xxWriteBlock(data1,1,0,0);
+    T55xxWriteBlock(data2,2,0,0);
+
+    //Config Block
+    T55xxWriteBlock(0x00147040,0,0,0);
+    LED_D_OFF();
+
+    DbpString("DONE!");
+}
+
+// Define 9bit header for EM410x tags
+#define EM410X_HEADER          0x1FF
+#define EM410X_ID_LENGTH       40
+
+void WriteEM410x(uint32_t card, uint32_t id_hi, uint32_t id_lo)
+{
+    int i, id_bit;
+    uint64_t id = EM410X_HEADER;
+    uint64_t rev_id = 0;       // reversed ID
+    int c_parity[4];   // column parity
+    int r_parity = 0;  // row parity
+    uint32_t clock = 0;
+
+    // Reverse ID bits given as parameter (for simpler operations)
+    for (i = 0; i < EM410X_ID_LENGTH; ++i) {
+        if (i < 32) {
+            rev_id = (rev_id << 1) | (id_lo & 1);
+            id_lo >>= 1;
+        } else {
+            rev_id = (rev_id << 1) | (id_hi & 1);
+            id_hi >>= 1;
+        }
+    }
+
+    for (i = 0; i < EM410X_ID_LENGTH; ++i) {
+        id_bit = rev_id & 1;
+
+        if (i % 4 == 0) {
+            // Don't write row parity bit at start of parsing
+            if (i)
+                id = (id << 1) | r_parity;
+            // Start counting parity for new row
+            r_parity = id_bit;
+        } else {
+            // Count row parity
+            r_parity ^= id_bit;
+        }
+
+        // First elements in column?
+        if (i < 4)
+            // Fill out first elements
+            c_parity[i] = id_bit;
+        else
+            // Count column parity
+            c_parity[i % 4] ^= id_bit;
+
+        // Insert ID bit
+        id = (id << 1) | id_bit;
+        rev_id >>= 1;
+    }
+
+    // Insert parity bit of last row
+    id = (id << 1) | r_parity;
+
+    // Fill out column parity at the end of tag
+    for (i = 0; i < 4; ++i)
+        id = (id << 1) | c_parity[i];
+
+    // Add stop bit
+    id <<= 1;
+
+    Dbprintf("Started writing %s tag ...", card ? "T55x7":"T5555");
+    LED_D_ON();
+
+    // Write EM410x ID
+    T55xxWriteBlock((uint32_t)(id >> 32), 1, 0, 0);
+    T55xxWriteBlock((uint32_t)id, 2, 0, 0);
+
+    // Config for EM410x (RF/64, Manchester, Maxblock=2)
+    if (card) {
+        // Clock rate is stored in bits 8-15 of the card value
+        clock = (card & 0xFF00) >> 8;
+        Dbprintf("Clock rate: %d", clock);
+        switch (clock)
+        {
+        case 32:
+            clock = T55x7_BITRATE_RF_32;
+            break;
+        case 16:
+            clock = T55x7_BITRATE_RF_16;
+            break;
+        case 0:
+            // A value of 0 is assumed to be 64 for backwards-compatibility
+            // Fall through...
+        case 64:
+            clock = T55x7_BITRATE_RF_64;
+            break;
+        default:
+            Dbprintf("Invalid clock rate: %d", clock);
+            return;
+        }
+
+        // Writing configuration for T55x7 tag
+        T55xxWriteBlock(clock      |
+                        T55x7_MODULATION_MANCHESTER |
+                        2 << T55x7_MAXBLOCK_SHIFT,
+                        0, 0, 0);
+    }
+    else
+        // Writing configuration for T5555(Q5) tag
+        T55xxWriteBlock(0x1F << T5555_BITRATE_SHIFT |
+                        T5555_MODULATION_MANCHESTER   |
+                        2 << T5555_MAXBLOCK_SHIFT,
+                        0, 0, 0);
+
+    LED_D_OFF();
+    Dbprintf("Tag %s written with 0x%08x%08x\n", card ? "T55x7":"T5555",
+             (uint32_t)(id >> 32), (uint32_t)id);
+}
+
+// Clone Indala 64-bit tag by UID to T55x7
+void CopyIndala64toT55x7(int hi, int lo)
+{
+
+    //Program the 2 data blocks for supplied 64bit UID
+    // and the block 0 for Indala64 format
+    T55xxWriteBlock(hi,1,0,0);
+    T55xxWriteBlock(lo,2,0,0);
+    //Config for Indala (RF/32;PSK1 with RF/2;Maxblock=2)
+    T55xxWriteBlock(T55x7_BITRATE_RF_32    |
+                    T55x7_MODULATION_PSK1 |
+                    2 << T55x7_MAXBLOCK_SHIFT,
+                    0, 0, 0);
+    //Alternative config for Indala (Extended mode;RF/32;PSK1 with RF/2;Maxblock=2;Inverse data)
+    // T5567WriteBlock(0x603E1042,0);
+
+    DbpString("DONE!");
+
+}
+
+void CopyIndala224toT55x7(int uid1, int uid2, int uid3, int uid4, int uid5, int uid6, int uid7)
+{
+
+    //Program the 7 data blocks for supplied 224bit UID
+    // and the block 0 for Indala224 format
+    T55xxWriteBlock(uid1,1,0,0);
+    T55xxWriteBlock(uid2,2,0,0);
+    T55xxWriteBlock(uid3,3,0,0);
+    T55xxWriteBlock(uid4,4,0,0);
+    T55xxWriteBlock(uid5,5,0,0);
+    T55xxWriteBlock(uid6,6,0,0);
+    T55xxWriteBlock(uid7,7,0,0);
+    //Config for Indala (RF/32;PSK1 with RF/2;Maxblock=7)
+    T55xxWriteBlock(T55x7_BITRATE_RF_32    |
+                    T55x7_MODULATION_PSK1 |
+                    7 << T55x7_MAXBLOCK_SHIFT,
+                    0,0,0);
+    //Alternative config for Indala (Extended mode;RF/32;PSK1 with RF/2;Maxblock=7;Inverse data)
+    // T5567WriteBlock(0x603E10E2,0);
+
+    DbpString("DONE!");
+
+}
+
+
+#define abs(x) ( ((x)<0) ? -(x) : (x) )
+#define max(x,y) ( x<y ? y:x)
+
+int DemodPCF7931(uint8_t **outBlocks) {
+    uint8_t BitStream[256];
+    uint8_t Blocks[8][16];
+    uint8_t *GraphBuffer = (uint8_t *)BigBuf;
+    int GraphTraceLen = sizeof(BigBuf);
+    int i, j, lastval, bitidx, half_switch;
+    int clock = 64;
+    int tolerance = clock / 8;
+    int pmc, block_done;
+    int lc, warnings = 0;
+    int num_blocks = 0;
+    int lmin=128, lmax=128;
+    uint8_t dir;
+
+       LFSetupFPGAForADC(95, true);
+       DoAcquisition_default(0, 0);
+
+
+    lmin = 64;
+    lmax = 192;
+
+    i = 2;
+
+    /* Find first local max/min */
+    if(GraphBuffer[1] > GraphBuffer[0]) {
+        while(i < GraphTraceLen) {
+            if( !(GraphBuffer[i] > GraphBuffer[i-1]) && GraphBuffer[i] > lmax)
+                break;
+            i++;
+        }
+        dir = 0;
+    }
+    else {
+        while(i < GraphTraceLen) {
+            if( !(GraphBuffer[i] < GraphBuffer[i-1]) && GraphBuffer[i] < lmin)
+                break;
+            i++;
+        }
+        dir = 1;
+    }
+
+    lastval = i++;
+    half_switch = 0;
+    pmc = 0;
+    block_done = 0;
+
+    for (bitidx = 0; i < GraphTraceLen; i++)
+    {
+        if ( (GraphBuffer[i-1] > GraphBuffer[i] && dir == 1 && GraphBuffer[i] > lmax) || (GraphBuffer[i-1] < GraphBuffer[i] && dir == 0 && GraphBuffer[i] < lmin))
+        {
+            lc = i - lastval;
+            lastval = i;
+
+            // Switch depending on lc length:
+            // Tolerance is 1/8 of clock rate (arbitrary)
+            if (abs(lc-clock/4) < tolerance) {
+                // 16T0
+                if((i - pmc) == lc) { /* 16T0 was previous one */
+                    /* It's a PMC ! */
+                    i += (128+127+16+32+33+16)-1;
+                    lastval = i;
+                    pmc = 0;
+                    block_done = 1;
+                }
+                else {
+                    pmc = i;
+                }
+            } else if (abs(lc-clock/2) < tolerance) {
+                // 32TO
+                if((i - pmc) == lc) { /* 16T0 was previous one */
+                    /* It's a PMC ! */
+                    i += (128+127+16+32+33)-1;
+                    lastval = i;
+                    pmc = 0;
+                    block_done = 1;
+                }
+                else if(half_switch == 1) {
+                    BitStream[bitidx++] = 0;
+                    half_switch = 0;
+                }
+                else
+                    half_switch++;
+            } else if (abs(lc-clock) < tolerance) {
+                // 64TO
+                BitStream[bitidx++] = 1;
+            } else {
+                // Error
+                warnings++;
+                if (warnings > 10)
+                {
+                    Dbprintf("Error: too many detection errors, aborting.");
+                    return 0;
+                }
+            }
+
+            if(block_done == 1) {
+                if(bitidx == 128) {
+                    for(j=0; j<16; j++) {
+                        Blocks[num_blocks][j] = 128*BitStream[j*8+7]+
+                                64*BitStream[j*8+6]+
+                                32*BitStream[j*8+5]+
+                                16*BitStream[j*8+4]+
+                                8*BitStream[j*8+3]+
+                                4*BitStream[j*8+2]+
+                                2*BitStream[j*8+1]+
+                                BitStream[j*8];
+                    }
+                    num_blocks++;
+                }
+                bitidx = 0;
+                block_done = 0;
+                half_switch = 0;
+            }
+            if(i < GraphTraceLen)
+            {
+                if (GraphBuffer[i-1] > GraphBuffer[i]) dir=0;
+                else dir = 1;
+            }
+        }
+        if(bitidx==255)
+            bitidx=0;
+        warnings = 0;
+        if(num_blocks == 4) break;
+    }
+    memcpy(outBlocks, Blocks, 16*num_blocks);
+    return num_blocks;
+}
+
+int IsBlock0PCF7931(uint8_t *Block) {
+    // Assume RFU means 0 :)
+    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
+        return 1;
+    if((memcmp(Block+9, "\x00\x00\x00\x00\x00\x00\x00", 7) == 0) && Block[7] == 0) // PAC disabled, can it *really* happen ?
+        return 1;
+    return 0;
+}
+
+int IsBlock1PCF7931(uint8_t *Block) {
+    // Assume RFU means 0 :)
+    if(Block[10] == 0 && Block[11] == 0 && Block[12] == 0 && Block[13] == 0)
+        if((Block[14] & 0x7f) <= 9 && Block[15] <= 9)
+            return 1;
+
+    return 0;
+}
+
+#define ALLOC 16
+
+void ReadPCF7931() {
+    uint8_t Blocks[8][17];
+    uint8_t tmpBlocks[4][16];
+    int i, j, ind, ind2, n;
+    int num_blocks = 0;
+    int max_blocks = 8;
+    int ident = 0;
+    int error = 0;
+    int tries = 0;
+
+    memset(Blocks, 0, 8*17*sizeof(uint8_t));
+
+    do {
+        memset(tmpBlocks, 0, 4*16*sizeof(uint8_t));
+        n = DemodPCF7931((uint8_t**)tmpBlocks);
+        if(!n)
+            error++;
+        if(error==10 && num_blocks == 0) {
+            Dbprintf("Error, no tag or bad tag");
+            return;
+        }
+        else if (tries==20 || error==10) {
+            Dbprintf("Error reading the tag");
+            Dbprintf("Here is the partial content");
+            goto end;
+        }
+
+        for(i=0; i<n; i++)
+            Dbprintf("(dbg) %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
+                     tmpBlocks[i][0], tmpBlocks[i][1], tmpBlocks[i][2], tmpBlocks[i][3], tmpBlocks[i][4], tmpBlocks[i][5], tmpBlocks[i][6], tmpBlocks[i][7],
+                    tmpBlocks[i][8], tmpBlocks[i][9], tmpBlocks[i][10], tmpBlocks[i][11], tmpBlocks[i][12], tmpBlocks[i][13], tmpBlocks[i][14], tmpBlocks[i][15]);
+        if(!ident) {
+            for(i=0; i<n; i++) {
+                if(IsBlock0PCF7931(tmpBlocks[i])) {
+                    // Found block 0 ?
+                    if(i < n-1 && IsBlock1PCF7931(tmpBlocks[i+1])) {
+                        // Found block 1!
+                        // \o/
+                        ident = 1;
+                        memcpy(Blocks[0], tmpBlocks[i], 16);
+                        Blocks[0][ALLOC] = 1;
+                        memcpy(Blocks[1], tmpBlocks[i+1], 16);
+                        Blocks[1][ALLOC] = 1;
+                        max_blocks = max((Blocks[1][14] & 0x7f), Blocks[1][15]) + 1;
+                        // Debug print
+                        Dbprintf("(dbg) Max blocks: %d", max_blocks);
+                        num_blocks = 2;
+                        // Handle following blocks
+                        for(j=i+2, ind2=2; j!=i; j++, ind2++, num_blocks++) {
+                            if(j==n) j=0;
+                            if(j==i) break;
+                            memcpy(Blocks[ind2], tmpBlocks[j], 16);
+                            Blocks[ind2][ALLOC] = 1;
+                        }
+                        break;
+                    }
+                }
+            }
+        }
+        else {
+            for(i=0; i<n; i++) { // Look for identical block in known blocks
+                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
+                    for(j=0; j<max_blocks; j++) {
+                        if(Blocks[j][ALLOC] == 1 && !memcmp(tmpBlocks[i], Blocks[j], 16)) {
+                            // Found an identical block
+                            for(ind=i-1,ind2=j-1; ind >= 0; ind--,ind2--) {
+                                if(ind2 < 0)
+                                    ind2 = max_blocks;
+                                if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
+                                    // Dbprintf("Tmp %d -> Block %d", ind, ind2);
+                                    memcpy(Blocks[ind2], tmpBlocks[ind], 16);
+                                    Blocks[ind2][ALLOC] = 1;
+                                    num_blocks++;
+                                    if(num_blocks == max_blocks) goto end;
+                                }
+                            }
+                            for(ind=i+1,ind2=j+1; ind < n; ind++,ind2++) {
+                                if(ind2 > max_blocks)
+                                    ind2 = 0;
+                                if(!Blocks[ind2][ALLOC]) { // Block ind2 not already found
+                                    // Dbprintf("Tmp %d -> Block %d", ind, ind2);
+                                    memcpy(Blocks[ind2], tmpBlocks[ind], 16);
+                                    Blocks[ind2][ALLOC] = 1;
+                                    num_blocks++;
+                                    if(num_blocks == max_blocks) goto end;
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        tries++;
+        if (BUTTON_PRESS()) return;
+    } while (num_blocks != max_blocks);
+end:
+    Dbprintf("-----------------------------------------");
+    Dbprintf("Memory content:");
+    Dbprintf("-----------------------------------------");
+    for(i=0; i<max_blocks; i++) {
+        if(Blocks[i][ALLOC]==1)
+            Dbprintf("%02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
+                     Blocks[i][0], Blocks[i][1], Blocks[i][2], Blocks[i][3], Blocks[i][4], Blocks[i][5], Blocks[i][6], Blocks[i][7],
+                    Blocks[i][8], Blocks[i][9], Blocks[i][10], Blocks[i][11], Blocks[i][12], Blocks[i][13], Blocks[i][14], Blocks[i][15]);
+        else
+            Dbprintf("<missing block %d>", i);
+    }
+    Dbprintf("-----------------------------------------");
+
+    return ;
+}
+
+
+//-----------------------------------
+// EM4469 / EM4305 routines
+//-----------------------------------
+#define FWD_CMD_LOGIN 0xC //including the even parity, binary mirrored
+#define FWD_CMD_WRITE 0xA
+#define FWD_CMD_READ 0x9
+#define FWD_CMD_DISABLE 0x5
+
+
+uint8_t forwardLink_data[64]; //array of forwarded bits
+uint8_t * forward_ptr; //ptr for forward message preparation
+uint8_t fwd_bit_sz; //forwardlink bit counter
+uint8_t * fwd_write_ptr; //forwardlink bit pointer
+
+//====================================================================
+// prepares command bits
+// see EM4469 spec
+//====================================================================
+//--------------------------------------------------------------------
+uint8_t Prepare_Cmd( uint8_t cmd ) {
+    //--------------------------------------------------------------------
+
+    *forward_ptr++ = 0; //start bit
+    *forward_ptr++ = 0; //second pause for 4050 code
+
+    *forward_ptr++ = cmd;
+    cmd >>= 1;
+    *forward_ptr++ = cmd;
+    cmd >>= 1;
+    *forward_ptr++ = cmd;
+    cmd >>= 1;
+    *forward_ptr++ = cmd;
+
+    return 6; //return number of emited bits
+}
+
+//====================================================================
+// prepares address bits
+// see EM4469 spec
+//====================================================================
+
+//--------------------------------------------------------------------
+uint8_t Prepare_Addr( uint8_t addr ) {
+    //--------------------------------------------------------------------
+
+    register uint8_t line_parity;
+
+    uint8_t i;
+    line_parity = 0;
+    for(i=0;i<6;i++) {
+        *forward_ptr++ = addr;
+        line_parity ^= addr;
+        addr >>= 1;
+    }
+
+    *forward_ptr++ = (line_parity & 1);
+
+    return 7; //return number of emited bits
+}
+
+//====================================================================
+// prepares data bits intreleaved with parity bits
+// see EM4469 spec
+//====================================================================
+
+//--------------------------------------------------------------------
+uint8_t Prepare_Data( uint16_t data_low, uint16_t data_hi) {
+    //--------------------------------------------------------------------
+
+    register uint8_t line_parity;
+    register uint8_t column_parity;
+    register uint8_t i, j;
+    register uint16_t data;
+
+    data = data_low;
+    column_parity = 0;
+
+    for(i=0; i<4; i++) {
+        line_parity = 0;
+        for(j=0; j<8; j++) {
+            line_parity ^= data;
+            column_parity ^= (data & 1) << j;
+            *forward_ptr++ = data;
+            data >>= 1;
+        }
+        *forward_ptr++ = line_parity;
+        if(i == 1)
+            data = data_hi;
+    }
+
+    for(j=0; j<8; j++) {
+        *forward_ptr++ = column_parity;
+        column_parity >>= 1;
+    }
+    *forward_ptr = 0;
+
+    return 45; //return number of emited bits
+}
+
+//====================================================================
+// Forward Link send function
+// Requires: forwarLink_data filled with valid bits (1 bit per byte)
+// fwd_bit_count set with number of bits to be sent
+//====================================================================
+void SendForward(uint8_t fwd_bit_count) {
+
+    fwd_write_ptr = forwardLink_data;
+    fwd_bit_sz = fwd_bit_count;
+
+    LED_D_ON();
+
+    //Field on
+    FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+
+    // Give it a bit of time for the resonant antenna to settle.
+    // And for the tag to fully power up
+    SpinDelay(150);
+
+    // force 1st mod pulse (start gap must be longer for 4305)
+    fwd_bit_sz--; //prepare next bit modulation
+    fwd_write_ptr++;
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
+    SpinDelayUs(55*8); //55 cycles off (8us each)for 4305
+    FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);//field on
+    SpinDelayUs(16*8); //16 cycles on (8us each)
+
+    // now start writting
+    while(fwd_bit_sz-- > 0) { //prepare next bit modulation
+        if(((*fwd_write_ptr++) & 1) == 1)
+            SpinDelayUs(32*8); //32 cycles at 125Khz (8us each)
+        else {
+            //These timings work for 4469/4269/4305 (with the 55*8 above)
+            FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
+            SpinDelayUs(23*8); //16-4 cycles off (8us each)
+            FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+            FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);//field on
+            SpinDelayUs(9*8); //16 cycles on (8us each)
+        }
+    }
+}
+
+void EM4xLogin(uint32_t Password) {
+
+    uint8_t fwd_bit_count;
+
+    forward_ptr = forwardLink_data;
+    fwd_bit_count = Prepare_Cmd( FWD_CMD_LOGIN );
+    fwd_bit_count += Prepare_Data( Password&0xFFFF, Password>>16 );
+
+    SendForward(fwd_bit_count);
+
+    //Wait for command to complete
+    SpinDelay(20);
+
+}
+
+void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
+
+    uint8_t fwd_bit_count;
+    uint8_t *dest = (uint8_t *)BigBuf;
+    int m=0, i=0;
+
+    //If password mode do login
+    if (PwdMode == 1) EM4xLogin(Pwd);
+
+    forward_ptr = forwardLink_data;
+    fwd_bit_count = Prepare_Cmd( FWD_CMD_READ );
+    fwd_bit_count += Prepare_Addr( Address );
+
+    m = sizeof(BigBuf);
+    // Clear destination buffer before sending the command
+    memset(dest, 128, m);
+    // Connect the A/D to the peak-detected low-frequency path.
+    SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+    // Now set up the SSC to get the ADC samples that are now streaming at us.
+    FpgaSetupSsc();
+
+    SendForward(fwd_bit_count);
+
+    // Now do the acquisition
+    i = 0;
+    for(;;) {
+        if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+            AT91C_BASE_SSC->SSC_THR = 0x43;
+        }
+        if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+            dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+            i++;
+            if (i >= m) break;
+        }
+    }
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
+    LED_D_OFF();
+}
+
+void EM4xWriteWord(uint32_t Data, uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
+
+    uint8_t fwd_bit_count;
+
+    //If password mode do login
+    if (PwdMode == 1) EM4xLogin(Pwd);
+
+    forward_ptr = forwardLink_data;
+    fwd_bit_count = Prepare_Cmd( FWD_CMD_WRITE );
+    fwd_bit_count += Prepare_Addr( Address );
+    fwd_bit_count += Prepare_Data( Data&0xFFFF, Data>>16 );
+
+    SendForward(fwd_bit_count);
+
+    //Wait for write to complete
+    SpinDelay(20);
+    FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
+    LED_D_OFF();
+}
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