-void SimulateTagLowFrequency(int period, int ledcontrol)
-{
- int i;
- BYTE *tab = (BYTE *)BigBuf;
-
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);
-
- PIO_ENABLE = (1 << GPIO_SSC_DOUT) | (1 << GPIO_SSC_CLK);
-
- PIO_OUTPUT_ENABLE = (1 << GPIO_SSC_DOUT);
- PIO_OUTPUT_DISABLE = (1 << GPIO_SSC_CLK);
-
-#define SHORT_COIL() LOW(GPIO_SSC_DOUT)
-#define OPEN_COIL() HIGH(GPIO_SSC_DOUT)
-
- i = 0;
- for(;;) {
- while(!(PIO_PIN_DATA_STATUS & (1<<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(PIO_PIN_DATA_STATUS & (1<<GPIO_SSC_CLK)) {
- if(BUTTON_PRESS()) {
- DbpString("Stopped");
- return;
- }
- WDT_HIT();
- }
-
- i++;
- if(i == period) i = 0;
- }
-}
-
-// compose fc/8 fc/10 waveform
-static void fc(int c, int *n) {
- BYTE *dest = (BYTE *)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
-static 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, ledcontrol);
-
- if (ledcontrol)
- LED_A_OFF();
-}
-
-// loop to capture raw HID waveform then FSK demodulate the TAG ID from it
-static void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
-{
- BYTE *dest = (BYTE *)BigBuf;
- int m=0, n=0, i=0, idx=0, found=0, lastval=0;
- DWORD hi=0, lo=0;
-
- FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
- FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-
- // Connect the A/D to the peak-detected low-frequency path.
- SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
-
- // Give it a bit of time for the resonant antenna to settle.
- SpinDelay(50);
-
- // Now set up the SSC to get the ADC samples that are now streaming at us.
- FpgaSetupSsc();
-
- for(;;) {
- WDT_HIT();
- if (ledcontrol)
- LED_A_ON();
- if(BUTTON_PRESS()) {
- DbpString("Stopped");
- if (ledcontrol)
- LED_A_OFF();
- return;
- }
-
- i = 0;
- m = sizeof(BigBuf);
- memset(dest,128,m);
- for(;;) {
- if(SSC_STATUS & (SSC_STATUS_TX_READY)) {
- SSC_TRANSMIT_HOLDING = 0x43;
- if (ledcontrol)
- LED_D_ON();
- }
- if(SSC_STATUS & (SSC_STATUS_RX_READY)) {
- dest[i] = (BYTE)SSC_RECEIVE_HOLDING;
- // 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 (ledcontrol)
- LED_D_OFF();
- if(i >= m) {
- break;
- }
- }
- }
-
- // FSK demodulator
-
- // sync to first lo-hi transition
- for( idx=1; idx<m; idx++) {
- if (dest[idx-1]<dest[idx])
- lastval=idx;
- break;
- }
- WDT_HIT();
-
- // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
- // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
- // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
- for( i=0; idx<m; idx++) {
- if (dest[idx-1]<dest[idx]) {
- dest[i]=idx-lastval;
- if (dest[i] <= 8) {
- dest[i]=1;
- } else {
- dest[i]=0;
- }
-
- lastval=idx;
- i++;
- }
- }
- m=i;
- WDT_HIT();
-
- // we now have a set of cycle counts, loop over previous results and aggregate data into bit patterns
- lastval=dest[0];
- idx=0;
- i=0;
- n=0;
- for( idx=0; idx<m; idx++) {
- if (dest[idx]==lastval) {
- n++;
- } else {
- // a bit time is five fc/10 or six fc/8 cycles so figure out how many bits a pattern width represents,
- // an extra fc/8 pattern preceeds every 4 bits (about 200 cycles) just to complicate things but it gets
- // swallowed up by rounding
- // expected results are 1 or 2 bits, any more and it's an invalid manchester encoding
- // special start of frame markers use invalid manchester states (no transitions) by using sequences
- // like 111000
- if (dest[idx-1]) {
- n=(n+1)/6; // fc/8 in sets of 6
- } else {
- n=(n+1)/5; // fc/10 in sets of 5
- }
- switch (n) { // stuff appropriate bits in buffer
- case 0:
- case 1: // one bit
- dest[i++]=dest[idx-1];
- break;
- case 2: // two bits
- dest[i++]=dest[idx-1];
- dest[i++]=dest[idx-1];
- break;
- case 3: // 3 bit start of frame markers
- dest[i++]=dest[idx-1];
- dest[i++]=dest[idx-1];
- dest[i++]=dest[idx-1];
- break;
- // When a logic 0 is immediately followed by the start of the next transmisson
- // (special pattern) a pattern of 4 bit duration lengths is created.
- case 4:
- dest[i++]=dest[idx-1];
- dest[i++]=dest[idx-1];
- dest[i++]=dest[idx-1];
- dest[i++]=dest[idx-1];
- break;
- default: // this shouldn't happen, don't stuff any bits
- break;
- }
- n=0;
- lastval=dest[idx];
- }
- }
- m=i;
- WDT_HIT();
-
- // 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
- for( idx=0; idx<m-6; idx++) {
- // search for a start of frame marker
- if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
- {
- found=1;
- idx+=6;
- if (found && (hi|lo)) {
- DbpString("TAG ID");
- DbpIntegers(hi, lo, (lo>>1)&0xffff);
- /* if we're only looking for one tag */
- if (findone)
- {
- *high = hi;
- *low = lo;
- return;
- }
- hi=0;
- lo=0;
- found=0;
- }
- }
- if (found) {
- if (dest[idx] && (!dest[idx+1]) ) {
- hi=(hi<<1)|(lo>>31);
- lo=(lo<<1)|0;
- } else if ( (!dest[idx]) && dest[idx+1]) {
- hi=(hi<<1)|(lo>>31);
- lo=(lo<<1)|1;
- } else {
- found=0;
- hi=0;
- lo=0;
- }
- idx++;
- }
- if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
- {
- found=1;
- idx+=6;
- if (found && (hi|lo)) {
- DbpString("TAG ID");
- DbpIntegers(hi, lo, (lo>>1)&0xffff);
- /* if we're only looking for one tag */
- if (findone)
- {
- *high = hi;
- *low = lo;
- return;
- }
- hi=0;
- lo=0;
- found=0;
- }
- }
- }
- WDT_HIT();
- }
-}
-
projects / proxmark3-svn / blobdiff