if (ledcontrol)
LED_A_OFF();
}
-void setup_for_125khz()
-{
- 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();
-
-}
-void get_samples(int ledcontrol, uint8_t* dest, int size)
-{
- int i = 0;
-
- memset(dest,128,size);
- for(;;) {
- if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
- AT91C_BASE_SSC->SSC_THR = 0x43;
- if (ledcontrol) LED_D_ON();
- }
- 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 (ledcontrol) LED_D_OFF();
- if(i >= size) {
- break;
- }
- }
- }
-}
-uint8_t fsk_demod(uint8_t * dest, int size)
+size_t fsk_demod(uint8_t * dest, size_t size)
{
- uint8_t last_transition = 0;
- uint8_t idx = 1;
+ uint32_t last_transition = 0;
+ uint32_t idx = 1;
// 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
uint8_t threshold_value = 127;
- WDT_HIT();
// sync to first lo-hi transition, and threshold
if(dest[0] < threshold_value) dest[0] = 0;
else dest[0] = 1;
- uint8_t numBits = 0;
+ size_t numBits = 0;
// 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(idx = 1; idx < size; idx++) {
-
// threshold current value
if (dest[idx] < threshold_value) dest[idx] = 0;
else dest[idx] = 1;
return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
}
-uint8_t aggregate_bits(uint8_t *dest,uint8_t size, uint8_t h2l_crossing_value,uint8_t l2h_crossing_value, uint8_t maxConsequtiveBits )
+
+size_t aggregate_bits(uint8_t *dest,size_t size, uint8_t h2l_crossing_value,uint8_t l2h_crossing_value, uint8_t maxConsequtiveBits )
{
uint8_t lastval=dest[0];
- uint8_t idx=0;
- uint8_t numBits=0;
- uint8_t n=1, i=0;
+ uint32_t idx=0;
+ size_t numBits=0;
+ uint32_t n=1;
for( idx=1; idx < size; idx++) {
continue;
}
//if lastval was 1, we have a 1->0 crossing
- if ( lastval ) {
- n=(n+1)/7;
+ if ( dest[idx-1] ) {
+ n=(n+1) / h2l_crossing_value;
} else {// 0->1 crossing
- n=(n+1)/6;
+ n=(n+1) / l2h_crossing_value;
}
- if(n < 13)
+ if (n == 0) n = 1;
+
+ if(n < maxConsequtiveBits)
{
- memset(dest+i, lastval ^ 1, n);
+ memset(dest+numBits, dest[idx-1] , n);
numBits += n;
}
n=0;
{
uint8_t *dest = (uint8_t *)BigBuf;
- int size=0, idx=0, found=0;
+ size_t size=0,idx=0; //, found=0;
uint32_t hi2=0, hi=0, lo=0;
- // Configure to go in 125Khz listen mode
- SetupToAcquireRawAdcSamples(0);
- for(;;) {
- WDT_HIT();
- if (ledcontrol)
- LED_A_ON();
- if(BUTTON_PRESS()) {
- DbpString("Stopped");
- if (ledcontrol)
- LED_A_OFF();
- return;
- }
+ while(!BUTTON_PRESS()) {
+ // Configure to go in 125Khz listen mode
+ SetupToAcquireRawAdcSamples(0);
+
+ WDT_HIT();
+ if (ledcontrol) LED_A_ON();
DoAcquisition125k_internal(true);
size = sizeof(BigBuf);
// FSK demodulator
size = fsk_demod(dest, size);
-
WDT_HIT();
// we now have a set of cycle counts, loop over previous results and aggregate data into bit patterns
-
// 1->0 : fc/8 in sets of 6
// 0->1 : fc/10 in sets of 5
size = aggregate_bits(dest,size, 6,5,5);
// 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
uint8_t frame_marker_mask[] = {1,1,1,0,0,0};
+ int numshifts = 0;
+ idx = 0;
+ while( idx + sizeof(frame_marker_mask) < size) {
+ // search for a start of frame marker
+ if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
+ { // frame marker found
+ idx+=sizeof(frame_marker_mask);
- for( idx=0; idx < size-sizeof(frame_marker_mask); idx++) {
-
- if (found) {
- if(dest[idx] == dest[idx+1])
- {// 1 1 or 00
- found=0;
- hi2=0;
- hi=0;
- lo=0;
- }else
- {
- //Shift in a bit. Start by shifting high registers
+ while(dest[idx] != dest[idx+1] && idx < size-2)
+ { // Keep going until next frame marker (or error)
+ // Shift in a bit. Start by shifting high registers
hi2 = (hi2<<1)|(hi>>31);
hi = (hi<<1)|(lo>>31);
//Then, shift in a 0 or one into low
if (dest[idx] && !dest[idx+1]) // 1 0
lo=(lo<<1)|0;
else // 0 1
- lo=(lo<<1)|1;
+ lo=(lo<<1)|
+ 1;
+ numshifts ++;
+ idx += 2;
}
- idx++;
- }
-
- // search for a start of frame marker
- if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
- { // Found start of frame marker
- found=1;
- idx+=sizeof(frame_marker_mask);
- if (found && (hi2|hi|lo)) {
+ //Dbprintf("Num shifts: %d ", numshifts);
+ // Hopefully, we read a tag and hit upon the next frame marker
+ if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
+ {
if (hi2 != 0){
Dbprintf("TAG ID: %x%08x%08x (%d)",
(unsigned int) hi2, (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
Dbprintf("TAG ID: %x%08x (%d)",
(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
}
- /* if we're only looking for one tag */
- if (findone)
- {
- *high = hi;
- *low = lo;
- return;
- }
- hi2=0;
- hi=0;
- lo=0;
- found=0;
}
+
+ // reset
+ hi2 = hi = lo = 0;
+ numshifts = 0;
+ }else
+ {
+ idx++;
}
}
WDT_HIT();
+
}
+ DbpString("Stopped");
+ if (ledcontrol) LED_A_OFF();
}
uint32_t bytebits_to_byte(uint8_t* src, int numbits)
void CmdIOdemodFSK(int findone, int *high, int *low, int ledcontrol)
{
uint8_t *dest = (uint8_t *)BigBuf;
- int size=0, idx=0;
+
+ size_t size=0, idx=0;
uint32_t code=0, code2=0;
- //uint32_t hi2=0, hi=0, lo=0;
- setup_for_125khz();
- for(;;) {
+ while(!BUTTON_PRESS()) {
+
+ // Configure to go in 125Khz listen mode
+ SetupToAcquireRawAdcSamples(0);
+
WDT_HIT();
- if (ledcontrol)
- LED_A_ON();
- if(BUTTON_PRESS()) {
- DbpString("Stopped");
- if (ledcontrol)
- LED_A_OFF();
- return;
- }
+ if (ledcontrol) LED_A_ON();
DoAcquisition125k_internal(true);
size = sizeof(BigBuf);
// FSK demodulator
size = fsk_demod(dest, size);
WDT_HIT();
+
// we now have a set of cycle counts, loop over previous results and aggregate data into bit patterns
// 1->0 : fc/8 in sets of 7
// 0->1 : fc/10 in sets of 6
WDT_HIT();
+ //Handle the data
uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1};
for( idx=0; idx < size - 64; idx++) {
return;
}
}
+ WDT_HIT();
}
- WDT_HIT();
+ DbpString("Stopped");
+ if (ledcontrol) LED_A_OFF();
}
/*------------------------------
projects / proxmark3-svn / commitdiff