// 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
+//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];
+ }
+ 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
//takes 1s and 0s and searches for EM410x format - output EM ID
uint64_t Em410xDecode(uint8_t *BitStream, size_t size)
int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
{
int i;
- int high = 0, low = 255;
*clk=DetectASKClock(BinStream, *size, *clk); //clock default
if (*clk<8) *clk =64;
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 < 129) ){ //throw away static (anything < 1 graph)
- //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
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;
//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 = 255;
+ int clk2 = *clk;
*clk=DetectASKClock(BinStream, *size, *clk); //clock default
- uint8_t BitStream[502] = {0};
+ //uint8_t BitStream[502] = {0};
+ //HACK: if clock not detected correctly - default
if (*clk<8) *clk =64;
- if (*clk<32) *clk=32;
+ if (*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 < 129)){ //throw away static high has to be more than 0 on graph.
- //noise <= -10 here
- // 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++;
+ //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++;
+ //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++;
+ //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++;
+ //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++;
+ //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++;
- }
+ //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
+ // 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)
return 0;
}
+// 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
+int parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
+{
+ uint8_t ans = 0;
+ for (int i = 0; i < bitLen; i++){
+ ans ^= ((bits >> i) & 1);
+ }
+ //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
+ return (ans == pType);
+}
+
+// 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;
+ }
+ // 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)
+{
+ static const uint8_t THRESHOLD = 123;
+ uint32_t idx=0;
+ //make sure buffer has data
+ if (size < 96*50) 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 -2;
+
+ // FSK demodulator
+ size = fskdemod(dest, size, 50, 1, 10, 8); // RF/64 and invert
+ if (size < 96) return -3; //did we get a good demod?
+
+ uint8_t mask[] = {0,0,0,0,0,0,0,1};
+ for( idx=0; idx < (size - 96); idx++) {
+ if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
+ // frame marker found
+ //return ID start index and size
+ return idx;
+ //size should always be 96
+ }
+ }
+ //never found mask
+ return -4;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an Farpointe Data (pyramid) ID
+int PyramiddemodFSK(uint8_t *dest, size_t size)
+{
+ static const uint8_t THRESHOLD = 123;
+ uint32_t idx=0;
+ // size_t size2 = size;
+ //make sure buffer has data
+ if (size < 128*50) return -5;
+ //test samples are not just noise
+ uint8_t justNoise = 1;
+ for(idx=0; idx < size && justNoise ;idx++){
+ justNoise = dest[idx] < THRESHOLD;
+ }
+ if(justNoise) return -1;
+
+ // FSK demodulator
+ size = fskdemod(dest, size, 50, 1, 10, 8); // RF/64 and invert
+ if (size < 128) return -2; //did we get a good demod?
+
+ uint8_t mask[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+ for( idx=0; idx < (size - 128); idx++) {
+ if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
+ // frame marker found
+ return idx;
+ }
+ }
+ //never found mask
+ return -4;
+}
+
// 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=255;
- int clk[]={16,32,40,50,64,100,128,256};
+ 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;
//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 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};
+ 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 < 6; ++clkCnt){
}
int iii=0;
int best=0;
- for (iii=0; iii<7;++iii){
+ for (iii=0; iii<8;++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]) ){
int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
{
int i=0;
- int peak=0;
- int low=255;
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 (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 peak, low;
+ getHiLo(dest, loopCnt, &peak, &low, 75, 75);
+
//PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
int ii;
uint8_t clkCnt;
int peaksdet[]={0,0,0,0,0,0,0,0,0};
//test each valid clock from smallest to greatest to see which lines up
for(clkCnt=0; clkCnt < 6; ++clkCnt){
- if (clk[clkCnt] == 32){
+ if (clk[clkCnt] >= 32){
tol=1;
}else{
tol=0;
}
//by marshmellow (attempt to get rid of high immediately after a low)
-void pskCleanWave(uint8_t *bitStream, size_t size)
+void pskCleanWave(uint8_t *BitStream, size_t size)
{
int i;
- int low=255;
- 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 - demodulate PSK wave or NRZ wave (both similar enough)
+//by marshmellow - demodulate PSK1 wave or NRZ wave (both similar enough)
//peaks switch 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)
{
int clk2 = DetectpskNRZClock(dest, *size, *clk);
*clk=clk2;
uint32_t i;
- uint8_t high=0, low=255;
+ 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
+ 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;
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
+//countFC is to detect the field clock and bit clock rates.
+//for fsk or ask not psk or nrz
+uint32_t countFC(uint8_t *BitStream, size_t size)
+{
+ // get high/low thresholds
+ int high, low;
+ getHiLo(BitStream,10, &high, &low, 100, 100);
+ // get zero crossing
+ uint8_t zeroC = (high-low)/2+low;
+ uint8_t clk[]={8,16,32,40,50,64,100,128};
+ 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 rfLens[] = {0,0,0,0,0,0,0,0,0,0,0};
+ // uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0};
+ uint8_t fcLensFnd = 0;
+ uint8_t rfLensFnd = 0;
+ uint8_t lastBit=0;
+ uint8_t curBit=0;
+ uint8_t lastFCcnt=0;
+ uint32_t errCnt=0;
+ uint32_t fcCounter = 0;
+ uint32_t rfCounter = 0;
+ uint8_t firstBitFnd = 0;
+ int i;
+
+ // prime i to first up transition
+ for (i = 1; i < size; i++)
+ if (BitStream[i]>=zeroC && BitStream[i-1]<zeroC)
+ break;
+
+ for (; i < size; i++){
+ curBit = BitStream[i];
+ lastBit = BitStream[i-1];
+ if (lastBit<zeroC && curBit >= zeroC){
+ // new up transition
+ fcCounter++;
+ rfCounter++;
+ if (fcCounter > 3 && fcCounter < 256){
+ //we've counted enough that it could be a valid field clock
+
+ //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++;
+
+ //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<10; ii++){
+ if (rfLens[ii]==rfCounter){
+ //rfCnts[ii]++;
+ rfCounter=0;
+ break;
+ }
+ }
+ if (rfCounter>0 && rfLensFnd<10){
+ //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+ //rfCnts[rfLensFnd]++;
+ rfLens[rfLensFnd++]=rfCounter;
+ }
+ } else {
+ //PrintAndLog("DEBUG i: %d",i);
+ firstBitFnd++;
+ }
+ rfCounter=0;
+ lastFCcnt=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
+ //PrintAndLog("FCCntr %d",fcCounter);
+ fcCnts[fcLensFnd]++;
+ fcLens[fcLensFnd++]=fcCounter;
+ }
+ } else{
+ // hmmm this should not happen often - count them
+ errCnt++;
+ }
+ // reset counter
+ fcCounter=0;
+ } else {
+ // count sample
+ fcCounter++;
+ rfCounter++;
+ }
+ }
+ // if too many errors return errors as negative number (IS THIS NEEDED?)
+ if (errCnt>100) return -1*errCnt;
+
+ uint8_t maxCnt1=0, best1=9, best2=9, best3=9, rfHighest=10, rfHighest2=10, rfHighest3=10;
+
+ // go through fclens and find which ones are bigest 2
+ for (i=0; i<10; i++){
+ // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d, RF %d",fcLens[i],fcCnts[i],errCnt,rfLens[i]);
+
+ // 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;
+ }
+ //get highest 2 RF values (might need to get more values to compare or compare all?)
+ if (rfLens[i]>rfLens[rfHighest]){
+ rfHighest3=rfHighest2;
+ rfHighest2=rfHighest;
+ rfHighest=i;
+ } else if(rfLens[i]>rfLens[rfHighest2]){
+ rfHighest3=rfHighest2;
+ rfHighest2=i;
+ } else if(rfLens[i]>rfLens[rfHighest3]){
+ rfHighest3=i;
+ }
+ }
+
+ // set allowed clock remainder tolerance to be 1 large field clock length
+ // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
+ int tol1 = (fcLens[best1]>fcLens[best2]) ? fcLens[best1] : fcLens[best2];
+
+ // 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) ii=7; // oops we went too far
+
+ // TODO: take top 3 answers and compare to known Field clocks to get top 2
+
+ uint32_t fcs=0;
+ // PrintAndLog("DEBUG: Best %d best2 %d best3 %d, clk %d, clk2 %d",fcLens[best1],fcLens[best2],fcLens[best3],clk[i],clk[ii]);
+ //
+
+ if (fcLens[best1]>fcLens[best2]){
+ fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best1])<<8) | ((fcLens[best2]));
+ } else {
+ fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best2])<<8) | ((fcLens[best1]));
+ }
+
+ return fcs;
+}
projects / proxmark3-svn / blobdiff