// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
-// Low frequency commands
+// Low frequency demod/decode commands
//-----------------------------------------------------------------------------
#include <stdlib.h>
#include <string.h>
#include "lfdemod.h"
-//by marshmellow
-//takes 1s and 0s and searches for EM410x format - output EM ID
-uint64_t Em410xDecode(uint8_t *BitStream, size_t size)
-{
- //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
- // otherwise could be a void with no arguments
- //set defaults
- int high=0, low=128;
- uint64_t lo=0;
-
- uint32_t i = 0;
- uint32_t initLoopMax = 65;
- if (initLoopMax>size) initLoopMax=size;
- for (;i < initLoopMax; ++i) //65 samples should be plenty to find high and low values
- {
- if (BitStream[i] > high)
- high = BitStream[i];
- else if (BitStream[i] < low)
- low = BitStream[i];
+uint8_t justNoise(uint8_t *BitStream, size_t size)
+{
+ static const uint8_t THRESHOLD = 123;
+ //test samples are not just noise
+ uint8_t justNoise1 = 1;
+ for(size_t idx=0; idx < size && justNoise1 ;idx++){
+ justNoise1 = BitStream[idx] < THRESHOLD;
}
- if (((high !=1)||(low !=0))){ //allow only 1s and 0s
- // PrintAndLog("no data found");
- return 0;
+ return justNoise1;
+}
+
+//by marshmellow
+//get high and low with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
+int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
+{
+ *high=0;
+ *low=255;
+ // get high and low thresholds
+ for (int i=0; i < size; i++){
+ if (BitStream[i] > *high) *high = BitStream[i];
+ if (BitStream[i] < *low) *low = BitStream[i];
}
- uint8_t parityTest=0;
- // 111111111 bit pattern represent start of frame
- uint8_t frame_marker_mask[] = {1,1,1,1,1,1,1,1,1};
- uint32_t idx = 0;
- uint32_t ii=0;
- uint8_t resetCnt = 0;
- while( (idx + 64) < size) {
- restart:
- // search for a start of frame marker
- if ( memcmp(BitStream+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
- { // frame marker found
- idx+=9;
- for (i=0; i<10;i++){
- for(ii=0; ii<5; ++ii){
- parityTest += BitStream[(i*5)+ii+idx];
- }
- if (parityTest== ((parityTest>>1)<<1)){
- parityTest=0;
- for (ii=0; ii<4;++ii){
- lo=(lo<<1LL)|(BitStream[(i*5)+ii+idx]);
- }
- //PrintAndLog("DEBUG: EM parity passed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d,lo: %d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1],lo);
- }else {//parity failed
- //PrintAndLog("DEBUG: EM parity failed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1]);
- parityTest=0;
- idx-=8;
- if (resetCnt>5)return 0;
- resetCnt++;
- goto restart;//continue;
- }
- }
- //skip last 5 bit parity test for simplicity.
- return lo;
- }else{
- idx++;
- }
+ if (*high < 123) return -1; // just noise
+ *high = (int)(((*high-128)*(((float)fuzzHi)/100))+128);
+ *low = (int)(((*low-128)*(((float)fuzzLo)/100))+128);
+ return 1;
+}
+
+// by marshmellow
+// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
+// returns 1 if passed
+uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
+{
+ uint8_t ans = 0;
+ for (uint8_t i = 0; i < bitLen; i++){
+ ans ^= ((bits >> i) & 1);
}
- return 0;
+ //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
+ return (ans == pType);
+}
+
+//by marshmellow
+//search for given preamble in given BitStream and return startIndex and length
+uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
+{
+ uint8_t foundCnt=0;
+ for (int idx=0; idx < *size - pLen; idx++){
+ if (memcmp(BitStream+idx, preamble, pLen) == 0){
+ //first index found
+ foundCnt++;
+ if (foundCnt == 1){
+ *startIdx = idx;
+ }
+ if (foundCnt == 2){
+ *size = idx - *startIdx;
+ return 1;
+ }
+ }
+ }
+ return 0;
+}
+
+
+//by marshmellow
+//takes 1s and 0s and searches for EM410x format - output EM ID
+uint64_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx)
+{
+ //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
+ // otherwise could be a void with no arguments
+ //set defaults
+ uint64_t lo=0;
+ uint32_t i = 0;
+ if (BitStream[1]>1){ //allow only 1s and 0s
+ // PrintAndLog("no data found");
+ return 0;
+ }
+ // 111111111 bit pattern represent start of frame
+ uint8_t preamble[] = {1,1,1,1,1,1,1,1,1};
+ uint32_t idx = 0;
+ uint32_t parityBits = 0;
+ uint8_t errChk = 0;
+ *startIdx = 0;
+ for (uint8_t extraBitChk=0; extraBitChk<5; extraBitChk++){
+ errChk = preambleSearch(BitStream+extraBitChk+*startIdx, preamble, sizeof(preamble), size, startIdx);
+ if (errChk == 0) return 0;
+ idx = *startIdx + 9;
+ for (i=0; i<10;i++){ //loop through 10 sets of 5 bits (50-10p = 40 bits)
+ parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
+ //check even parity
+ if (parityTest(parityBits, 5, 0) == 0){
+ //parity failed try next bit (in the case of 1111111111) but last 9 = preamble
+ startIdx++;
+ errChk = 0;
+ break;
+ }
+ for (uint8_t ii=0; ii<4; ii++){
+ lo = (lo << 1LL) | (BitStream[(i*5)+ii+idx]);
+ }
+ }
+ if (errChk != 0) return lo;
+ //skip last 5 bit parity test for simplicity.
+ // *size = 64;
+ }
+ return 0;
}
//by marshmellow
int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
{
int i;
- int high = 0, low = 128;
+ int clk2=*clk;
*clk=DetectASKClock(BinStream, *size, *clk); //clock default
- if (*clk<8) *clk =64;
- if (*clk<32) *clk=32;
+ // if autodetected too low then adjust //MAY NEED ADJUSTMENT
+ if (clk2==0 && *clk<8) *clk =64;
+ if (clk2==0 && *clk<32) *clk=32;
if (*invert != 0 && *invert != 1) *invert=0;
uint32_t initLoopMax = 200;
if (initLoopMax > *size) initLoopMax=*size;
// Detect high and lows
- for (i = 0; i < initLoopMax; ++i) //200 samples should be enough to find high and low values
- {
- if (BinStream[i] > high)
- high = BinStream[i];
- else if (BinStream[i] < low)
- low = BinStream[i];
- }
- if ((high < 158) ){ //throw away static
- //PrintAndLog("no data found");
- return -2;
- }
- //25% fuzz in case highs and lows aren't clipped [marshmellow]
- high=(int)(((high-128)*.75)+128);
- low= (int)(((low-128)*.75)+128);
+ // 25% fuzz in case highs and lows aren't clipped [marshmellow]
+ int high, low, ans;
+ ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
+ if (ans<1) return -2; //just noise
- //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
+ // PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
int lastBit = 0; //set first clock check
uint32_t bitnum = 0; //output counter
int tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
- if (*clk==32)tol=1; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
+ if (*clk<=32)tol=1; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
int iii = 0;
uint32_t gLen = *size;
if (gLen > 3000) gLen=3000;
uint32_t bestStart = *size;
uint32_t bestErrCnt = (*size/1000);
uint32_t maxErr = (*size/1000);
- //PrintAndLog("DEBUG - lastbit - %d",lastBit);
- //loop to find first wave that works
+ // PrintAndLog("DEBUG - lastbit - %d",lastBit);
+ // loop to find first wave that works
for (iii=0; iii < gLen; ++iii){
if ((BinStream[iii] >= high) || (BinStream[iii] <= low)){
lastBit=iii-*clk;
errCnt=0;
- //loop through to see if this start location works
+ // loop through to see if this start location works
for (i = iii; i < *size; ++i) {
if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
lastBit+=*clk;
return bestErrCnt;
}
+//by marshmellow
+//encode binary data into binary manchester
+int ManchesterEncode(uint8_t *BitStream, size_t size)
+{
+ size_t modIdx=20000, i=0;
+ if (size>modIdx) return -1;
+ for (size_t idx=0; idx < size; idx++){
+ BitStream[idx+modIdx++] = BitStream[idx];
+ BitStream[idx+modIdx++] = BitStream[idx]^1;
+ }
+ for (; i<(size*2); i++){
+ BitStream[i] = BitStream[i+20000];
+ }
+ return i;
+}
+
//by marshmellow
//take 10 and 01 and manchester decode
//run through 2 times and take least errCnt
return errCnt;
}
-
//by marshmellow
//take 01 or 10 = 0 and 11 or 00 = 1
-int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset)
+int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
{
uint8_t bitnum=0;
uint32_t errCnt =0;
- uint32_t i=1;
+ uint32_t i;
i=offset;
- for (;i<*size-2;i+=2){
+ for (;i<*size-2; i+=2){
if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
- BitStream[bitnum++]=1;
+ BitStream[bitnum++]=1^invert;
} else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
- BitStream[bitnum++]=0;
+ BitStream[bitnum++]=invert;
} else {
BitStream[bitnum++]=77;
errCnt++;
{
uint32_t i;
// int invert=0; //invert default
- int high = 0, low = 128;
+ int clk2 = *clk;
*clk=DetectASKClock(BinStream, *size, *clk); //clock default
- uint8_t BitStream[502] = {0};
+ //uint8_t BitStream[502] = {0};
- if (*clk<8) *clk =64;
- if (*clk<32) *clk=32;
+ //HACK: if clock not detected correctly - default
+ if (clk2==0 && *clk<8) *clk =64;
+ if (clk2==0 && *clk<32 && clk2==0) *clk=32;
if (*invert != 0 && *invert != 1) *invert =0;
uint32_t initLoopMax = 200;
if (initLoopMax > *size) initLoopMax=*size;
// Detect high and lows
- for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values
- {
- if (BinStream[i] > high)
- high = BinStream[i];
- else if (BinStream[i] < low)
- low = BinStream[i];
- }
- if ((high < 158)){ //throw away static
- // PrintAndLog("no data found");
- return -2;
- }
//25% fuzz in case highs and lows aren't clipped [marshmellow]
- high=(int)(((high-128)*.75)+128);
- low= (int)(((low-128)*.75)+128);
+ int high, low, ans;
+ ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
+ if (ans<1) return -2; //just noise
//PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
int lastBit = 0; //set first clock check
uint8_t errCnt =0;
uint32_t bestStart = *size;
uint32_t bestErrCnt = (*size/1000);
+ uint32_t maxErr = bestErrCnt;
uint8_t midBit=0;
//PrintAndLog("DEBUG - lastbit - %d",lastBit);
//loop to find first wave that works
for (i = iii; i < *size; ++i) {
if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
lastBit+=*clk;
- BitStream[bitnum] = *invert;
- bitnum++;
midBit=0;
} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
//low found and we are expecting a bar
lastBit+=*clk;
- BitStream[bitnum] = 1- *invert;
- bitnum++;
midBit=0;
} else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
//mid bar?
midBit=1;
- BitStream[bitnum]= 1- *invert;
- bitnum++;
} else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
//mid bar?
midBit=1;
- BitStream[bitnum]= *invert;
- bitnum++;
} else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
//no mid bar found
midBit=1;
- BitStream[bitnum]= BitStream[bitnum-1];
- bitnum++;
} else {
//mid value found or no bar supposed to be here
//should have hit a high or low based on clock!!
//debug
//PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
- if (bitnum > 0){
- BitStream[bitnum]=77;
- bitnum++;
- }
errCnt++;
lastBit+=*clk;//skip over until hit too many errors
if (errCnt > ((*size/1000))){ //allow 1 error for every 1000 samples else start over
errCnt=0;
- bitnum=0;//start over
break;
}
}
}
- if (bitnum>500) break;
+ if ((i-iii)>(500 * *clk)) break; //got enough bits
}
//we got more than 64 good bits and not all errors
- if ((bitnum > (64+errCnt)) && (errCnt<(*size/1000))) {
+ if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<(*size/1000))) {
//possible good read
- if (errCnt==0) break; //great read - finish
- if (bestStart == iii) break; //if current run == bestErrCnt run (after exhausted testing) then finish
+ if (errCnt==0){
+ bestStart=iii;
+ bestErrCnt=errCnt;
+ break; //great read - finish
+ }
if (errCnt<bestErrCnt){ //set this as new best run
bestErrCnt=errCnt;
bestStart = iii;
}
}
}
- if (iii>=gLen){ //exhausted test
- //if there was a ok test go back to that one and re-run the best run (then dump after that run)
- if (bestErrCnt < (*size/1000)) iii=bestStart;
- }
}
- if (bitnum>16){
- for (i=0; i < bitnum; ++i){
- BinStream[i]=BitStream[i];
+ if (bestErrCnt<maxErr){
+ //best run is good enough - set to best run and overwrite BinStream
+ iii=bestStart;
+ lastBit = bestStart - *clk;
+ bitnum=0;
+ for (i = iii; i < *size; ++i) {
+ if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
+ lastBit += *clk;
+ BinStream[bitnum] = *invert;
+ bitnum++;
+ midBit=0;
+ } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
+ //low found and we are expecting a bar
+ lastBit+=*clk;
+ BinStream[bitnum] = 1-*invert;
+ bitnum++;
+ midBit=0;
+ } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
+ //mid bar?
+ midBit=1;
+ BinStream[bitnum] = 1 - *invert;
+ bitnum++;
+ } else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
+ //mid bar?
+ midBit=1;
+ BinStream[bitnum] = *invert;
+ bitnum++;
+ } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
+ //no mid bar found
+ midBit=1;
+ if (bitnum!=0) BinStream[bitnum] = BinStream[bitnum-1];
+ bitnum++;
+
+ } else {
+ //mid value found or no bar supposed to be here
+ if ((i-lastBit)>(*clk+tol)){
+ //should have hit a high or low based on clock!!
+
+ //debug
+ //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
+ if (bitnum > 0){
+ BinStream[bitnum]=77;
+ bitnum++;
+ }
+
+ lastBit+=*clk;//skip over error
+ }
+ }
+ if (bitnum >=400) break;
}
*size=bitnum;
- } else return -1;
- return errCnt;
+ } else{
+ *invert=bestStart;
+ *clk=iii;
+ return -1;
+ }
+ return bestErrCnt;
}
//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
{
uint32_t last_transition = 0;
uint32_t idx = 1;
- uint32_t maxVal=0;
+ //uint32_t maxVal=0;
if (fchigh==0) fchigh=10;
if (fclow==0) fclow=8;
- // we do care about the actual theshold value as sometimes near the center of the
- // wave we may get static that changes direction of wave for one value
- // if our value is too low it might affect the read. and if our tag or
- // antenna is weak a setting too high might not see anything. [marshmellow]
- if (size<100) return 0;
- for(idx=1; idx<100; idx++){
- if(maxVal<dest[idx]) maxVal = dest[idx];
- }
- // set close to the top of the wave threshold with 25% margin for error
- // less likely to get a false transition up there.
- // (but have to be careful not to go too high and miss some short waves)
- uint8_t threshold_value = (uint8_t)(((maxVal-128)*.75)+128);
+ //set the threshold close to 0 (graph) or 128 std to avoid static
+ uint8_t threshold_value = 123;
// sync to first lo-hi transition, and threshold
if ( dest[idx-1]==1 ) {
n=myround2((float)(n+1)/((float)(rfLen)/(float)fclow));
} else {// 0->1 crossing
- n=myround2((float)(n+1)/((float)(rfLen-2)/(float)fchigh)); //-2 for fudge factor
+ n=myround2((float)(n+1)/((float)(rfLen-1)/(float)fchigh)); //-1 for fudge factor
}
if (n == 0) n = 1;
size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow);
return size;
}
+
// loop to get raw HID waveform then FSK demodulate the TAG ID from it
-int HIDdemodFSK(uint8_t *dest, size_t size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
+int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
{
+ if (justNoise(dest, *size)) return -1;
+
+ size_t numStart=0, size2=*size, startIdx=0;
+ // FSK demodulator
+ *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
+ if (*size < 96) return -2;
+ // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
+ uint8_t preamble[] = {0,0,0,1,1,1,0,1};
+ // find bitstring in array
+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+ if (errChk == 0) return -3; //preamble not found
- size_t idx=0; //, found=0; //size=0,
+ numStart = startIdx + sizeof(preamble);
+ // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
+ for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
+ if (dest[idx] == dest[idx+1]){
+ return -4; //not manchester data
+ }
+ *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)|1;
+ else // 0 1
+ *lo=(*lo<<1)|0;
+ }
+ return (int)startIdx;
+}
+
+// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
+int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
+{
+ if (justNoise(dest, *size)) return -1;
+
+ size_t numStart=0, size2=*size, startIdx=0;
// FSK demodulator
- size = fskdemod(dest, size,50,0,10,8);
-
- // 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;
- //one scan
- 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);
- 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;
- numshifts++;
- idx += 2;
- }
- // Hopefully, we read a tag and hit upon the next frame marker
- if(idx + sizeof(frame_marker_mask) < size)
- {
- if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
- {
- //good return
- return idx;
- }
- }
- // reset
- *hi2 = *hi = *lo = 0;
- numshifts = 0;
- }else {
- idx++;
- }
+ *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
+ if (*size < 96) return -2;
+
+ // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
+ uint8_t preamble[] = {0,0,0,0,1,1,1,1};
+
+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+ if (errChk == 0) return -3; //preamble not found
+
+ numStart = startIdx + sizeof(preamble);
+ // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
+ for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
+ if (dest[idx] == dest[idx+1])
+ return -4; //not manchester data
+ *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)|1;
+ else // 0 1
+ *lo=(*lo<<1)|0;
}
- return -1;
+ return (int)startIdx;
}
uint32_t bytebits_to_byte(uint8_t* src, size_t numbits)
int IOdemodFSK(uint8_t *dest, size_t size)
{
- static const uint8_t THRESHOLD = 140;
- uint32_t idx=0;
+ if (justNoise(dest, size)) return -1;
//make sure buffer has data
- if (size < 66) return -1;
- //test samples are not just noise
- uint8_t justNoise = 1;
- for(idx=0;idx< size && justNoise ;idx++){
- justNoise = dest[idx] < THRESHOLD;
- }
- if(justNoise) return 0;
-
+ if (size < 66*64) return -2;
// FSK demodulator
- size = fskdemod(dest, size, 64, 1, 10, 8); // RF/64 and invert
- if (size < 65) return -1; //did we get a good demod?
+ size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
+ if (size < 65) return -3; //did we get a good demod?
//Index map
//0 10 20 30 40 50 60
//| | | | | | |
//
//XSF(version)facility:codeone+codetwo
//Handle the data
- uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1};
- for( idx=0; idx < (size - 65); idx++) {
- if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
- //frame marker found
- if (!dest[idx+8] && dest[idx+17]==1 && dest[idx+26]==1 && dest[idx+35]==1 && dest[idx+44]==1 && dest[idx+53]==1){
- //confirmed proper separator bits found
- //return start position
- return (int) idx;
- }
+ size_t startIdx = 0;
+ uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
+ if (errChk == 0) return -4; //preamble not found
+
+ if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
+ //confirmed proper separator bits found
+ //return start position
+ return (int) startIdx;
+ }
+ return -5;
+}
+
+// by marshmellow
+// takes a array of binary values, start position, length of bits per parity (includes parity bit),
+// Parity Type (1 for odd 0 for even), and binary Length (length to run)
+size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
+{
+ uint32_t parityWd = 0;
+ size_t j = 0, bitCnt = 0;
+ for (int word = 0; word < (bLen); word+=pLen){
+ for (int bit=0; bit < pLen; bit++){
+ parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
+ BitStream[j++] = (BitStream[startIdx+word+bit]);
}
+ j--;
+ // if parity fails then return 0
+ if (parityTest(parityWd, pLen, pType) == 0) return -1;
+ bitCnt+=(pLen-1);
+ parityWd = 0;
}
- return 0;
+ // if we got here then all the parities passed
+ //return ID start index and size
+ return bitCnt;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an AWID ID
+int AWIDdemodFSK(uint8_t *dest, size_t *size)
+{
+ //make sure buffer has enough data
+ if (*size < 96*50) return -1;
+
+ if (justNoise(dest, *size)) return -2;
+
+ // FSK demodulator
+ *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
+ if (*size < 96) return -3; //did we get a good demod?
+
+ uint8_t preamble[] = {0,0,0,0,0,0,0,1};
+ size_t startIdx = 0;
+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+ if (errChk == 0) return -4; //preamble not found
+ if (*size != 96) return -5;
+ return (int)startIdx;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an Farpointe Data (pyramid) ID
+int PyramiddemodFSK(uint8_t *dest, size_t *size)
+{
+ //make sure buffer has data
+ if (*size < 128*50) return -5;
+
+ //test samples are not just noise
+ if (justNoise(dest, *size)) return -1;
+
+ // FSK demodulator
+ *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
+ if (*size < 128) return -2; //did we get a good demod?
+
+ uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+ size_t startIdx = 0;
+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+ if (errChk == 0) return -4; //preamble not found
+ if (*size != 128) return -3;
+ return (int)startIdx;
}
// by marshmellow
// maybe somehow adjust peak trimming value based on samples to fix?
int DetectASKClock(uint8_t dest[], size_t size, int clock)
{
- int i=0;
- int peak=0;
- int low=128;
- int clk[]={16,32,40,50,64,100,128,256};
- int loopCnt = 256; //don't need to loop through entire array...
- if (size<loopCnt) loopCnt = size;
+ int i=0;
+ int clk[]={8,16,32,40,50,64,100,128,256};
+ int loopCnt = 256; //don't need to loop through entire array...
+ if (size<loopCnt) loopCnt = size;
- //if we already have a valid clock quit
- for (;i<8;++i)
- if (clk[i] == clock) return clock;
+ //if we already have a valid clock quit
+
+ for (;i<8;++i)
+ if (clk[i] == clock) return clock;
- //get high and low peak
- for (i=0; i < loopCnt; ++i){
- if(dest[i] > peak){
- peak = dest[i];
- }
- if(dest[i] < low){
- low = dest[i];
- }
- }
- peak=(int)(((peak-128)*.75)+128);
- low= (int)(((low-128)*.75)+128);
- int ii;
- int clkCnt;
- int tol = 0;
- int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000};
- int errCnt=0;
- //test each valid clock from smallest to greatest to see which lines up
- for(clkCnt=0; clkCnt < 6; ++clkCnt){
- if (clk[clkCnt] == 32){
- tol=1;
- }else{
- tol=0;
- }
- bestErr[clkCnt]=1000;
- //try lining up the peaks by moving starting point (try first 256)
- for (ii=0; ii< loopCnt; ++ii){
- if ((dest[ii] >= peak) || (dest[ii] <= low)){
- errCnt=0;
- // now that we have the first one lined up test rest of wave array
- for (i=0; i<((int)(size/clk[clkCnt])-1); ++i){
- if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
- }else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
- }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
- }else{ //error no peak detected
- errCnt++;
- }
- }
- //if we found no errors this is correct one - return this clock
- if(errCnt==0) return clk[clkCnt];
- //if we found errors see if it is lowest so far and save it as best run
- if(errCnt<bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
- }
- }
- }
- int iii=0;
- int best=0;
- for (iii=0; iii<7;++iii){
- if (bestErr[iii]<bestErr[best]){
- // current best bit to error ratio vs new bit to error ratio
- if (((size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii]) ){
- best = iii;
- }
- }
- }
- return clk[best];
+ //get high and low peak
+ int peak, low;
+ getHiLo(dest, loopCnt, &peak, &low, 75, 75);
+
+ int ii;
+ int clkCnt;
+ int tol = 0;
+ int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
+ int errCnt=0;
+ //test each valid clock from smallest to greatest to see which lines up
+ for(clkCnt=0; clkCnt < 8; ++clkCnt){
+ if (clk[clkCnt] == 32){
+ tol=1;
+ }else{
+ tol=0;
+ }
+ bestErr[clkCnt]=1000;
+ //try lining up the peaks by moving starting point (try first 256)
+ for (ii=0; ii < loopCnt; ++ii){
+ if ((dest[ii] >= peak) || (dest[ii] <= low)){
+ errCnt=0;
+ // now that we have the first one lined up test rest of wave array
+ for (i=0; i<((int)((size-ii-tol)/clk[clkCnt])-1); ++i){
+ if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
+ }else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
+ }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
+ }else{ //error no peak detected
+ errCnt++;
+ }
+ }
+ //if we found no errors then we can stop here
+ // this is correct one - return this clock
+ //PrintAndLog("DEBUG: clk %d, err %d, ii %d, i %d",clk[clkCnt],errCnt,ii,i);
+ if(errCnt==0 && clkCnt<6) return clk[clkCnt];
+ //if we found errors see if it is lowest so far and save it as best run
+ if(errCnt<bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
+ }
+ }
+ }
+ uint8_t iii=0;
+ uint8_t best=0;
+ for (iii=0; iii<8; ++iii){
+ if (bestErr[iii]<bestErr[best]){
+ if (bestErr[iii]==0) bestErr[iii]=1;
+ // current best bit to error ratio vs new bit to error ratio
+ if (((size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii]) ){
+ best = iii;
+ }
+ }
+ }
+ return clk[best];
}
//by marshmellow
int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
{
int i=0;
- int peak=0;
- int low=128;
int clk[]={16,32,40,50,64,100,128,256};
int loopCnt = 2048; //don't need to loop through entire array...
if (size<loopCnt) loopCnt = size;
//if we already have a valid clock quit
- for (; i < 8; ++i)
+ for (; i < 7; ++i)
if (clk[i] == clock) return clock;
//get high and low peak
- for (i=0; i < loopCnt; ++i){
- if(dest[i] > peak){
- peak = dest[i];
- }
- if(dest[i] < low){
- low = dest[i];
- }
- }
- peak=(int)(((peak-128)*.90)+128);
- low= (int)(((low-128)*.90)+128);
+ int peak, low;
+ getHiLo(dest, loopCnt, &peak, &low, 75, 75);
+
//PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
int ii;
uint8_t clkCnt;
uint8_t tol = 0;
int peakcnt=0;
int errCnt=0;
- int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
- int peaksdet[]={0,0,0,0,0,0,0,0,0};
+ int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000};
+ int peaksdet[]={0,0,0,0,0,0,0,0};
//test each valid clock from smallest to greatest to see which lines up
- for(clkCnt=0; clkCnt < 6; ++clkCnt){
- if (clk[clkCnt] == 32){
- tol=0;
+ for(clkCnt=0; clkCnt < 7; ++clkCnt){
+ if (clk[clkCnt] <= 32){
+ tol=1;
}else{
tol=0;
}
errCnt=0;
peakcnt=0;
// now that we have the first one lined up test rest of wave array
- for (i=0; i < ((int)(size/clk[clkCnt])-1); ++i){
+ for (i=0; i < ((int)((size-ii-tol)/clk[clkCnt])-1); ++i){
if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
peakcnt++;
}else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
return clk[best];
}
-//by marshmellow (attempt to get rid of high immediately after a low)
-void pskCleanWave(uint8_t *bitStream, size_t size)
+// by marshmellow (attempt to get rid of high immediately after a low)
+void pskCleanWave(uint8_t *BitStream, size_t size)
{
int i;
- int low=128;
- int high=0;
int gap = 4;
- // int loopMax = 2048;
- int newLow=0;
+ int newLow=0;
int newHigh=0;
- for (i=0; i < size; ++i){
- if (bitStream[i] < low) low=bitStream[i];
- if (bitStream[i] > high) high=bitStream[i];
- }
- high = (int)(((high-128)*.80)+128);
- low = (int)(((low-128)*.90)+128);
- //low = (uint8_t)(((int)(low)-128)*.80)+128;
- for (i=0; i < size; ++i){
+ int high, low;
+ getHiLo(BitStream, size, &high, &low, 80, 90);
+
+ for (i=0; i < size; ++i){
if (newLow == 1){
- bitStream[i]=low+8;
- gap--;
+ if (BitStream[i]>low){
+ BitStream[i]=low+8;
+ gap--;
+ }
if (gap == 0){
newLow=0;
gap=4;
}
}else if (newHigh == 1){
- bitStream[i]=high-8;
- gap--;
+ if (BitStream[i]<high){
+ BitStream[i]=high-8;
+ gap--;
+ }
if (gap == 0){
newHigh=0;
gap=4;
}
}
- if (bitStream[i] <= low) newLow=1;
- if (bitStream[i] >= high) newHigh=1;
+ if (BitStream[i] <= low) newLow=1;
+ if (BitStream[i] >= high) newHigh=1;
}
return;
}
+// by marshmellow
+// convert psk1 demod to psk2 demod
+// only transition waves are 1s
+void psk1TOpsk2(uint8_t *BitStream, size_t size)
+{
+ size_t i=1;
+ uint8_t lastBit=BitStream[0];
+ for (; i<size; i++){
+ if (lastBit!=BitStream[i]){
+ lastBit=BitStream[i];
+ BitStream[i]=1;
+ } else {
+ BitStream[i]=0;
+ }
+ }
+ return;
+}
-//redesigned by marshmellow adjusted from existing decode functions
-//indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
+// redesigned by marshmellow adjusted from existing decode functions
+// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
{
//26 bit 40134 format (don't know other formats)
int i;
- int long_wait;
- long_wait = 29;//29 leading zeros in format
+ int long_wait=29;//29 leading zeros in format
int start;
int first = 0;
int first2 = 0;
// did not find start sequence
return -1;
}
- //found start once now test length by finding next one
// Inverting signal if needed
if (first == 1) {
for (i = start; i < *size; i++) {
}else *invert=0;
int iii;
+ //found start once now test length by finding next one
for (ii=start+29; ii <= *size - 250; ii++) {
first2 = bitStream[ii];
for (iii = ii; iii < ii + long_wait; iii++) {
return 1;
}
-
-//by marshmellow - demodulate PSK wave or NRZ wave (both similar enough)
-//peaks switch bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
+// by marshmellow - demodulate PSK1 wave or NRZ wave (both similar enough)
+// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
{
+ if (justNoise(dest, *size)) return -1;
pskCleanWave(dest,*size);
int clk2 = DetectpskNRZClock(dest, *size, *clk);
*clk=clk2;
uint32_t i;
- uint8_t high=0, low=128;
+ int high, low, ans;
+ ans = getHiLo(dest, 1260, &high, &low, 75, 80); //25% fuzz on high 20% fuzz on low
+ if (ans<1) return -2; //just noise
uint32_t gLen = *size;
- if (gLen > 1280) gLen=1280;
- // get high
- for (i=0; i < gLen; ++i){
- if (dest[i] > high) high = dest[i];
- if (dest[i] < low) low = dest[i];
- }
- //fudge high/low bars by 25%
- high = (uint8_t)((((int)(high)-128)*.75)+128);
- low = (uint8_t)((((int)(low)-128)*.80)+128);
-
//PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
int lastBit = 0; //set first clock check
uint32_t bitnum = 0; //output counter
- uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
- if (*clk==32)tol=2; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
+ uint8_t tol = 1; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
+ if (*clk==32) tol = 2; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
uint32_t iii = 0;
uint8_t errCnt =0;
uint32_t bestStart = *size;
uint32_t maxErr = (*size/1000);
uint32_t bestErrCnt = maxErr;
- //uint8_t midBit=0;
uint8_t curBit=0;
uint8_t bitHigh=0;
uint8_t ignorewin=*clk/8;
bestErrCnt = errCnt;
break; //great read - finish
}
- if (bestStart == iii) break; //if current run == bestErrCnt run (after exhausted testing) then finish
if (errCnt < bestErrCnt){ //set this as new best run
bestErrCnt = errCnt;
bestStart = iii;
return errCnt;
}
+//by marshmellow
+//detects the bit clock for FSK given the high and low Field Clocks
+uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
+{
+ uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
+ uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+ uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+ uint8_t rfLensFnd = 0;
+ uint8_t lastFCcnt=0;
+ uint32_t fcCounter = 0;
+ uint16_t rfCounter = 0;
+ uint8_t firstBitFnd = 0;
+ size_t i;
+
+ uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
+ rfLensFnd=0;
+ fcCounter=0;
+ rfCounter=0;
+ firstBitFnd=0;
+ //PrintAndLog("DEBUG: fcTol: %d",fcTol);
+ // prime i to first up transition
+ for (i = 1; i < size-1; i++)
+ if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
+ break;
+
+ for (; i < size-1; i++){
+ if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]){
+ // new peak
+ fcCounter++;
+ rfCounter++;
+ // if we got less than the small fc + tolerance then set it to the small fc
+ if (fcCounter < fcLow+fcTol)
+ fcCounter = fcLow;
+ else //set it to the large fc
+ fcCounter = fcHigh;
+
+ //look for bit clock (rf/xx)
+ if ((fcCounter<lastFCcnt || fcCounter>lastFCcnt)){
+ //not the same size as the last wave - start of new bit sequence
+
+ if (firstBitFnd>1){ //skip first wave change - probably not a complete bit
+ for (int ii=0; ii<15; ii++){
+ if (rfLens[ii]==rfCounter){
+ rfCnts[ii]++;
+ rfCounter=0;
+ break;
+ }
+ }
+ if (rfCounter>0 && rfLensFnd<15){
+ //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+ rfCnts[rfLensFnd]++;
+ rfLens[rfLensFnd++]=rfCounter;
+ }
+ } else {
+ firstBitFnd++;
+ }
+ rfCounter=0;
+ lastFCcnt=fcCounter;
+ }
+ fcCounter=0;
+ } else {
+ // count sample
+ fcCounter++;
+ rfCounter++;
+ }
+ }
+ uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
+
+ for (i=0; i<15; i++){
+ //PrintAndLog("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]);
+ //get highest 2 RF values (might need to get more values to compare or compare all?)
+ if (rfCnts[i]>rfCnts[rfHighest]){
+ rfHighest3=rfHighest2;
+ rfHighest2=rfHighest;
+ rfHighest=i;
+ } else if(rfCnts[i]>rfCnts[rfHighest2]){
+ rfHighest3=rfHighest2;
+ rfHighest2=i;
+ } else if(rfCnts[i]>rfCnts[rfHighest3]){
+ rfHighest3=i;
+ }
+ }
+ // set allowed clock remainder tolerance to be 1 large field clock length+1
+ // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
+ uint8_t tol1 = fcHigh+1;
+
+ //PrintAndLog("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
+
+ // loop to find the highest clock that has a remainder less than the tolerance
+ // compare samples counted divided by
+ int ii=7;
+ for (; ii>=0; ii--){
+ if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
+ if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
+ if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
+ break;
+ }
+ }
+ }
+ }
+
+ if (ii<0) return 0; // oops we went too far
+
+ return clk[ii];
+}
+
+//by marshmellow
+//countFC is to detect the field clock lengths.
+//counts and returns the 2 most common wave lengths
+uint16_t countFC(uint8_t *BitStream, size_t size)
+{
+ uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0};
+ uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
+ uint8_t fcLensFnd = 0;
+ uint8_t lastFCcnt=0;
+ uint32_t fcCounter = 0;
+ size_t i;
+
+ // prime i to first up transition
+ for (i = 1; i < size-1; i++)
+ if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
+ break;
+
+ for (; i < size-1; i++){
+ if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
+ // new up transition
+ fcCounter++;
+
+ //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
+ if (lastFCcnt==5 && fcCounter==9) fcCounter--;
+ //if odd and not rc/5 add one (for when we get a fc 9 instead of 10)
+ if ((fcCounter==9 && fcCounter & 1) || fcCounter==4) fcCounter++;
+
+ // save last field clock count (fc/xx)
+ // find which fcLens to save it to:
+ for (int ii=0; ii<10; ii++){
+ if (fcLens[ii]==fcCounter){
+ fcCnts[ii]++;
+ fcCounter=0;
+ break;
+ }
+ }
+ if (fcCounter>0 && fcLensFnd<10){
+ //add new fc length
+ fcCnts[fcLensFnd]++;
+ fcLens[fcLensFnd++]=fcCounter;
+ }
+ fcCounter=0;
+ } else {
+ // count sample
+ fcCounter++;
+ }
+ }
+
+ uint8_t best1=9, best2=9, best3=9;
+ uint16_t maxCnt1=0;
+ // go through fclens and find which ones are bigest 2
+ for (i=0; i<10; i++){
+ // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d",fcLens[i],fcCnts[i],errCnt);
+ // get the 3 best FC values
+ if (fcCnts[i]>maxCnt1) {
+ best3=best2;
+ best2=best1;
+ maxCnt1=fcCnts[i];
+ best1=i;
+ } else if(fcCnts[i]>fcCnts[best2]){
+ best3=best2;
+ best2=i;
+ } else if(fcCnts[i]>fcCnts[best3]){
+ best3=i;
+ }
+ }
+ uint8_t fcH=0, fcL=0;
+ if (fcLens[best1]>fcLens[best2]){
+ fcH=fcLens[best1];
+ fcL=fcLens[best2];
+ } else{
+ fcH=fcLens[best2];
+ fcL=fcLens[best1];
+ }
+
+ // TODO: take top 3 answers and compare to known Field clocks to get top 2
+
+ uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
+ // PrintAndLog("DEBUG: Best %d best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]);
+
+ return fcs;
+}
projects / proxmark3-svn / blobdiff