+//-----------------------------------------------------------------------------
+// Copyright (C) 2014
+//
+// 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.
+//-----------------------------------------------------------------------------
+// Low frequency 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,uint32_t BitLen)
+{
+ //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; //hi=0,
+
+ uint32_t i = 0;
+ uint32_t initLoopMax = 65;
+ if (initLoopMax>BitLen) initLoopMax=BitLen;
+
+ 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];
+ }
+ if (((high !=1)||(low !=0))){ //allow only 1s and 0s
+ // PrintAndLog("no data found");
+ return 0;
+ }
+ 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) < BitLen) {
+ 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;//sizeof(frame_marker_mask);
+ 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){
+ //hi = (hi<<1)|(lo>>31);
+ 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++;
+ }
+ }
+ return 0;
+}
+
+//by marshmellow
+//takes 2 arguments - clock and invert both as integers
+//attempts to demodulate ask while decoding manchester
+//prints binary found and saves in graphbuffer for further commands
+int askmandemod(uint8_t * BinStream,uint32_t *BitLen,int *clk, int *invert)
+{
+ int i;
+ int high = 0, low = 128;
+ *clk=DetectASKClock(BinStream,(size_t)*BitLen,*clk); //clock default
+
+ if (*clk<8) *clk =64;
+ if (*clk<32) *clk=32;
+ if (*invert != 1) *invert=0;
+
+ uint32_t initLoopMax = 200;
+ if (initLoopMax>*BitLen) initLoopMax=*BitLen;
+
+ // 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
+ 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;
+
+ //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
+ int iii = 0;
+ uint32_t gLen = *BitLen;
+ if (gLen > 3000) gLen=3000;
+ uint8_t errCnt =0;
+ uint32_t bestStart = *BitLen;
+ uint32_t bestErrCnt = (*BitLen/1000);
+ uint32_t maxErr = (*BitLen/1000);
+
+ //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
+ for (i = iii; i < *BitLen; ++i) {
+ if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
+ lastBit+=*clk;
+ } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
+ //low found and we are expecting a bar
+ lastBit+=*clk;
+ } 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!!
+
+ errCnt++;
+ lastBit+=*clk;//skip over until hit too many errors
+ if (errCnt>(maxErr)) break; //allow 1 error for every 1000 samples else start over
+ }
+ }
+ if ((i-iii) >(400 * *clk)) break; //got plenty of bits
+ }
+ //we got more than 64 good bits and not all errors
+ if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<maxErr)) {
+ //possible good read
+ 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 (bestErrCnt<maxErr){
+ //best run is good enough set to best run and set overwrite BinStream
+ iii=bestStart;
+ lastBit=bestStart-*clk;
+ bitnum=0;
+ for (i = iii; i < *BitLen; ++i) {
+ if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
+ lastBit+=*clk;
+ BinStream[bitnum] = *invert;
+ bitnum++;
+ } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
+ //low found and we are expecting a bar
+ lastBit+=*clk;
+ BinStream[bitnum] = 1-*invert;
+ 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!!
+
+ if (bitnum > 0){
+ BinStream[bitnum]=77;
+ bitnum++;
+ }
+
+ lastBit+=*clk;//skip over error
+ }
+ }
+ if (bitnum >=400) break;
+ }
+ *BitLen=bitnum;
+ } else{
+ *invert=bestStart;
+ *clk=iii;
+ return -1;
+ }
+ return bestErrCnt;
+}
+
+//by marshmellow
+//take 10 and 01 and manchester decode
+//run through 2 times and take least errCnt
+int manrawdecode(uint8_t * BitStream, int *bitLen)
+{
+ int bitnum=0;
+ int errCnt =0;
+ int i=1;
+ int bestErr = 1000;
+ int bestRun = 0;
+ int ii=1;
+ for (ii=1;ii<3;++ii){
+ i=1;
+ for (i=i+ii;i<*bitLen-2;i+=2){
+ if(BitStream[i]==1 && (BitStream[i+1]==0)){
+ } else if((BitStream[i]==0)&& BitStream[i+1]==1){
+ } else {
+ errCnt++;
+ }
+ if(bitnum>300) break;
+ }
+ if (bestErr>errCnt){
+ bestErr=errCnt;
+ bestRun=ii;
+ }
+ errCnt=0;
+ }
+ errCnt=bestErr;
+ if (errCnt<20){
+ ii=bestRun;
+ i=1;
+ for (i=i+ii;i<*bitLen-2;i+=2){
+ if(BitStream[i]==1 && (BitStream[i+1]==0)){
+ BitStream[bitnum++]=0;
+ } else if((BitStream[i]==0)&& BitStream[i+1]==1){
+ BitStream[bitnum++]=1;
+ } else {
+ BitStream[bitnum++]=77;
+ //errCnt++;
+ }
+ if(bitnum>300) break;
+ }
+ *bitLen=bitnum;
+ }
+ return errCnt;
+}
+
+
+//by marshmellow
+//take 01 or 10 = 0 and 11 or 00 = 1
+int BiphaseRawDecode(uint8_t * BitStream, int *bitLen, int offset)
+{
+ uint8_t bitnum = 0;
+ uint32_t errCnt = 0;
+ uint32_t i = 1;
+ i=offset;
+ for (;i<*bitLen-2;i+=2){
+ if((BitStream[i]==1 && BitStream[i+1]==0)||(BitStream[i]==0 && BitStream[i+1]==1)){
+ BitStream[bitnum++]=1;
+ } else if((BitStream[i]==0 && BitStream[i+1]==0)||(BitStream[i]==1 && BitStream[i+1]==1)){
+ BitStream[bitnum++]=0;
+ } else {
+ BitStream[bitnum++]=77;
+ errCnt++;
+ }
+ if(bitnum>250) break;
+ }
+ *bitLen=bitnum;
+ return errCnt;
+}
+
+//by marshmellow
+//takes 2 arguments - clock and invert both as integers
+//attempts to demodulate ask only
+//prints binary found and saves in graphbuffer for further commands
+int askrawdemod(uint8_t *BinStream, int *bitLen,int *clk, int *invert)
+{
+ uint32_t i;
+ // int invert=0; //invert default
+ int high = 0, low = 128;
+ *clk=DetectASKClock(BinStream,*bitLen,*clk); //clock default
+ uint8_t BitStream[502] = {0};
+
+ if (*clk<8) *clk =64;
+ if (*clk<32) *clk=32;
+ if (*invert != 1) *invert = 0;
+
+ uint32_t initLoopMax = 200;
+ if (initLoopMax>*bitLen) initLoopMax=*bitLen;
+ // 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
+ 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 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=1; //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;
+ uint32_t gLen = *bitLen;
+ if (gLen > 500) gLen=500;
+ uint8_t errCnt =0;
+ uint32_t bestStart = *bitLen;
+ uint32_t bestErrCnt = (*bitLen/1000);
+ uint8_t midBit=0;
+
+ //loop to find first wave that works
+ for (iii=0; iii < gLen; ++iii){
+ if ((BinStream[iii]>=high)||(BinStream[iii]<=low)){
+ lastBit=iii-*clk;
+ //loop through to see if this start location works
+ for (i = iii; i < *bitLen; ++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
+
+ if ((i-lastBit)>(*clk+tol)){
+ //should have hit a high or low based on clock!!
+
+ if (bitnum > 0){
+ BitStream[bitnum]=77;
+ bitnum++;
+ }
+
+ errCnt++;
+ lastBit+=*clk;//skip over until hit too many errors
+ if (errCnt>((*bitLen/1000))){ //allow 1 error for every 1000 samples else start over
+ errCnt=0;
+ bitnum=0;//start over
+ break;
+ }
+ }
+ }
+ if (bitnum>500) break;
+ }
+ //we got more than 64 good bits and not all errors
+ if ((bitnum > (64+errCnt)) && (errCnt<(*bitLen/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<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 < (*bitLen/1000)) iii=bestStart;
+ }
+ }
+ if (bitnum>16){
+
+ for (i=0; i < bitnum; ++i){
+ BinStream[i]=BitStream[i];
+ }
+ *bitLen = bitnum;
+ } else {
+ return -1;
+ }
+ return errCnt;
+}
+//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;
+ 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);
+
+ // sync to first lo-hi transition, and threshold
+ // Need to threshold first sample
+
+ if(dest[0] < threshold_value) dest[0] = 0;
+ else dest[0] = 1;
+
+ 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;
+
+ // Check for 0->1 transition
+ if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
+ if ((idx-last_transition)<(fclow-2)){ //0-5 = garbage noise
+ //do nothing with extra garbage
+ } else if ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves
+ dest[numBits]=1;
+ } else { //9+ = 10 waves
+ dest[numBits]=0;
+ }
+ last_transition = idx;
+ numBits++;
+ }
+ }
+ return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
+}
+
+uint32_t myround2(float f)
+{
+ if (f >= 2000) return 2000;//something bad happened
+ return (uint32_t) (f + (float)0.5);
+}
+
+//translate 11111100000 to 10
+size_t aggregate_bits(uint8_t *dest,size_t size, uint8_t rfLen, uint8_t maxConsequtiveBits, uint8_t invert,uint8_t fchigh,uint8_t fclow )// uint8_t h2l_crossing_value,uint8_t l2h_crossing_value,
+{
+ uint8_t lastval=dest[0];
+ uint32_t idx=0;
+ size_t numBits=0;
+ uint32_t n=1;
+
+ for( idx=1; idx < size; idx++) {
+
+ if (dest[idx]==lastval) {
+ n++;
+ continue;
+ }
+ //if lastval was 1, we have a 1->0 crossing
+ if ( dest[idx-1]==1 ) {
+ n=myround2((float)(n+1)/((float)(rfLen)/(float)fclow));
+ //n=(n+1) / h2l_crossing_value;
+ } else {// 0->1 crossing
+ n=myround2((float)(n+1)/((float)(rfLen-2)/(float)fchigh)); //-2 for fudge factor
+ //n=(n+1) / l2h_crossing_value;
+ }
+ if (n == 0) n = 1;
+
+ if(n < maxConsequtiveBits) //Consecutive
+ {
+ if(invert==0){ //invert bits
+ memset(dest+numBits, dest[idx-1] , n);
+ }else{
+ memset(dest+numBits, dest[idx-1]^1 , n);
+ }
+ numBits += n;
+ }
+ n=0;
+ lastval=dest[idx];
+ }//end for
+ return numBits;
+}
+//by marshmellow (from holiman's base)
+// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
+int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
+{
+ // FSK demodulator
+ size = fsk_wave_demod(dest, size, fchigh, fclow);
+ 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)
+{
+
+ size_t idx=0; //, found=0; //size=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++;
+ }
+ }
+ return -1;
+}
+
+uint32_t bytebits_to_byte(uint8_t* src, int numbits)
+{
+ uint32_t num = 0;
+ for(int i = 0 ; i < numbits ; i++) {
+ num = (num << 1) | (*src);
+ src++;
+ }
+ return num;
+}
+
+int IOdemodFSK(uint8_t *dest, size_t size)
+{
+ uint32_t idx=0;
+ //make sure buffer has data
+ if (size < 66) return -1;
+ //test samples are not just noise
+ uint8_t testMax=0;
+ for(idx=0;idx<65;idx++){
+ if (testMax<dest[idx]) testMax=dest[idx];
+ }
+ idx=0;
+ //if not just noise
+ if (testMax>170){
+ // 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?
+ //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
+ 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;
+ }
+ }
+ }
+ }
+ return 0;
+}
+
+// by marshmellow
+// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
+// 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;
+
+ //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;
+ int errCnt[]={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=1;
+ }else{
+ tol=0;
+ }
+ bestErr=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[clkCnt]=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[clkCnt]++;
+ }
+ }
+ //if we found no errors this is correct one - return this clock
+ if(errCnt[clkCnt]==0) return clk[clkCnt];
+ //if we found errors see if it is lowest so far and save it as best run
+ if(errCnt[clkCnt]<bestErr) bestErr=errCnt[clkCnt];
+ }
+ }
+ }
+ int iii=0;
+ int best=0;
+ for (iii=0; iii<6;++iii){
+ if (errCnt[iii]<errCnt[best]){
+ best = iii;
+ }
+ }
+ return clk[best];
+}
projects / proxmark3-svn / commitdiff