Merge pull request #98 from marshmellow42/master

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index c00222b3b69ca23a277f041a027c14a02d2e0feb..7d40d22e5aa44551835ae4ada1f69947f132e488 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -81,10 +81,8 @@ uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_
        //  otherwise could be a void with no arguments
        //set defaults
        uint32_t i = 0;
        //  otherwise could be a void with no arguments
        //set defaults
        uint32_t i = 0;

-       if (BitStream[1]>1){  //allow only 1s and 0s
-               // PrintAndLog("no data found");
-               return 0;
-       }
+       if (BitStream[1]>1) return 0;  //allow only 1s and 0s
+

        // 111111111 bit pattern represent start of frame
        //  include 0 in front to help get start pos
        uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
        // 111111111 bit pattern represent start of frame
        //  include 0 in front to help get start pos
        uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};


@@ -114,12 +112,12 @@ uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_
        return 0;
 }
 
        return 0;
 }
 

-// demodulates strong heavily clipped samples
+//by marshmellow
+//demodulates strong heavily clipped samples

 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
 {
        size_t bitCnt=0, smplCnt=0, errCnt=0;
        uint8_t waveHigh = 0;
 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
 {
        size_t bitCnt=0, smplCnt=0, errCnt=0;
        uint8_t waveHigh = 0;

-       //PrintAndLog("clk: %d", clk);

        for (size_t i=0; i < *size; i++){
                if (BinStream[i] >= high && waveHigh){
                        smplCnt++;
        for (size_t i=0; i < *size; i++){
                if (BinStream[i] >= high && waveHigh){
                        smplCnt++;


@@ -130,7 +128,7 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int
                                if (smplCnt > clk-(clk/4)-1) { //full clock
                                        if (smplCnt > clk + (clk/4)+1) { //too many samples
                                                errCnt++;
                                if (smplCnt > clk-(clk/4)-1) { //full clock
                                        if (smplCnt > clk + (clk/4)+1) { //too many samples
                                                errCnt++;

-                                               BinStream[bitCnt++]=77;
+                                               BinStream[bitCnt++]=7;

                                        } else if (waveHigh) {
                                                BinStream[bitCnt++] = invert;
                                                BinStream[bitCnt++] = invert;
                                        } else if (waveHigh) {
                                                BinStream[bitCnt++] = invert;
                                                BinStream[bitCnt++] = invert;


@@ -166,52 +164,81 @@ int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int
 }
 
 //by marshmellow
 }
 
 //by marshmellow

-//takes 3 arguments - clock, invert, maxErr as integers
-//attempts to demodulate ask while decoding manchester
-//prints binary found and saves in graphbuffer for further commands
-int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr)
+void askAmp(uint8_t *BitStream, size_t size)

 {
 {

-       size_t i;
+       for(size_t i = 1; i<size; i++){
+               if (BitStream[i]-BitStream[i-1]>=30) //large jump up
+                       BitStream[i]=127;
+               else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
+                       BitStream[i]=-127;
+       }
+       return;
+}
+
+//by marshmellow
+//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
+int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
+{
+       if (*size==0) return -1;

        int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
        if (*clk==0 || start < 0) return -3;
        int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
        if (*clk==0 || start < 0) return -3;

-       if (*invert != 1) *invert=0;
+       if (*invert != 1) *invert = 0;
+       if (amp==1) askAmp(BinStream, *size);
+

        uint8_t initLoopMax = 255;
        if (initLoopMax > *size) initLoopMax = *size;
        // Detect high and lows
        uint8_t initLoopMax = 255;
        if (initLoopMax > *size) initLoopMax = *size;
        // Detect high and lows

-       // 25% fuzz in case highs and lows aren't clipped [marshmellow]
+       //25% clip in case highs and lows aren't clipped [marshmellow]

        int high, low;
        int high, low;

-       if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) return -2; //just noise
+       if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) 
+               return -2; //just noise

 
 

+       size_t errCnt = 0;

        // if clean clipped waves detected run alternate demod
        if (DetectCleanAskWave(BinStream, *size, high, low)) {
        // if clean clipped waves detected run alternate demod
        if (DetectCleanAskWave(BinStream, *size, high, low)) {

-               cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
-               return manrawdecode(BinStream, size);   
+               errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
+               if (askType) //askman
+                       return manrawdecode(BinStream, size, 0);        
+               else //askraw
+                       return errCnt;

        }
 
        }
 

-       // PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
-       int lastBit;  //set first clock check
-       uint16_t bitnum = 0;     //output counter
+       int lastBit;  //set first clock check - can go negative
+       size_t i, bitnum = 0;     //output counter
+       uint8_t midBit = 0;

        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 = 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
-       uint16_t errCnt = 0, MaxBits = 512;
+       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
+       size_t MaxBits = 1024;

        lastBit = start - *clk;
        lastBit = start - *clk;

+

        for (i = start; i < *size; ++i) {
        for (i = start; i < *size; ++i) {

-               if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
-                       //high found and we are expecting a bar
-                       lastBit += *clk;
-                       BinStream[bitnum++] = *invert;
-               } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
-                       //low found and we are expecting a bar
+               if (i-lastBit >= *clk-tol){
+                       if (BinStream[i] >= high) {
+                               BinStream[bitnum++] = *invert;
+                       } else if (BinStream[i] <= low) {
+                               BinStream[bitnum++] = *invert ^ 1;
+                       } else if (i-lastBit >= *clk+tol) {
+                               if (bitnum > 0) {
+                                       BinStream[bitnum++]=7;
+                                       errCnt++;                                               
+                               } 
+                       } else { //in tolerance - looking for peak
+                               continue;
+                       }
+                       midBit = 0;

                        lastBit += *clk;
                        lastBit += *clk;

-                       BinStream[bitnum++] = *invert ^ 1;
-               } else if ((i-lastBit)>(*clk+tol)){
-                       //should have hit a high or low based on clock!!
-                       //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;
-                               errCnt++;
-                       }               
-                       lastBit += *clk;//skip over error
+               } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
+                       if (BinStream[i] >= high) {
+                               BinStream[bitnum++] = *invert;
+                       } else if (BinStream[i] <= low) {
+                               BinStream[bitnum++] = *invert ^ 1;
+                       } else if (i-lastBit >= *clk/2+tol) {
+                               BinStream[bitnum] = BinStream[bitnum-1];
+                               bitnum++;
+                       } else { //in tolerance - looking for peak
+                               continue;
+                       }
+                       midBit = 1;

                }
                if (bitnum >= MaxBits) break;
        }
                }
                if (bitnum >= MaxBits) break;
        }


@@ -219,33 +246,18 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
        return errCnt;
 }
 
        return errCnt;
 }
 

-//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
 //by marshmellow
 //take 10 and 01 and manchester decode
 //run through 2 times and take least errCnt

-int manrawdecode(uint8_t * BitStream, size_t *size)
+int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)

 {
        uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
        size_t i, ii;
        uint16_t bestErr = 1000, bestRun = 0;
 {
        uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
        size_t i, ii;
        uint16_t bestErr = 1000, bestRun = 0;

-       if (size == 0) return -1;
+       if (*size < 16) return -1;
+       //find correct start position [alignment]

        for (ii=0;ii<2;++ii){
        for (ii=0;ii<2;++ii){

-               for (i=ii; i<*size-2; i+=2)
+               for (i=ii; i<*size-3; i+=2)

                        if (BitStream[i]==BitStream[i+1])
                                errCnt++;
 
                        if (BitStream[i]==BitStream[i+1])
                                errCnt++;
 


@@ -255,13 +267,14 @@ int manrawdecode(uint8_t * BitStream, size_t *size)
                }
                errCnt=0;
        }
                }
                errCnt=0;
        }

-       for (i=bestRun; i < *size-2; i+=2){
+       //decode
+       for (i=bestRun; i < *size-3; i+=2){

                if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
                if(BitStream[i] == 1 && (BitStream[i+1] == 0)){

-                       BitStream[bitnum++]=0;
+                       BitStream[bitnum++]=invert;

                } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
                } else if((BitStream[i] == 0) && BitStream[i+1] == 1){

-                       BitStream[bitnum++]=1;
+                       BitStream[bitnum++]=invert^1;

                } else {
                } else {

-                       BitStream[bitnum++]=77;
+                       BitStream[bitnum++]=7;

                }
                if(bitnum>MaxBits) break;
        }
                }
                if(bitnum>MaxBits) break;
        }


@@ -269,6 +282,22 @@ int manrawdecode(uint8_t * BitStream, size_t *size)
        return bestErr;
 }
 
        return bestErr;
 }
 

+//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 01 or 10 = 1 and 11 or 00 = 0
 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
 //by marshmellow
 //take 01 or 10 = 1 and 11 or 00 = 0
 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010


@@ -291,7 +320,7 @@ int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
        for (i=offset; i<*size-3; i+=2){
                //check for phase error
                if (BitStream[i+1]==BitStream[i+2]) {
        for (i=offset; i<*size-3; i+=2){
                //check for phase error
                if (BitStream[i+1]==BitStream[i+2]) {

-                       BitStream[bitnum++]=77;
+                       BitStream[bitnum++]=7;

                        errCnt++;
                }
                if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
                        errCnt++;
                }
                if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){


@@ -299,7 +328,7 @@ int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
                } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
                        BitStream[bitnum++]=invert;
                } else {
                } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
                        BitStream[bitnum++]=invert;
                } else {

-                       BitStream[bitnum++]=77;
+                       BitStream[bitnum++]=7;

                        errCnt++;
                }
                if(bitnum>MaxBits) break;
                        errCnt++;
                }
                if(bitnum>MaxBits) break;


@@ -308,89 +337,7 @@ int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
        return errCnt;
 }
 
        return errCnt;
 }
 

-//by marshmellow
-void askAmp(uint8_t *BitStream, size_t size)
-{
-       int shift = 127;
-       int shiftedVal=0;
-       for(size_t i = 1; i<size; i++){
-               if (BitStream[i]-BitStream[i-1]>=30) //large jump up
-                       shift=127;
-               else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
-                       shift=-127;
-
-               shiftedVal=BitStream[i]+shift;
-
-               if (shiftedVal>255) 
-                       shiftedVal=255;
-               else if (shiftedVal<0) 
-                       shiftedVal=0;
-               BitStream[i-1] = shiftedVal;
-       }
-       return;
-}
-
-//by marshmellow
-//takes 3 arguments - clock, invert and maxErr as integers
-//attempts to demodulate ask only
-int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp)
-{
-       if (*size==0) return -1;
-       int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
-       if (*clk==0 || start < 0) return -1;
-       if (*invert != 1) *invert = 0;
-       if (amp==1) askAmp(BinStream, *size);
-
-       uint8_t initLoopMax = 255;
-       if (initLoopMax > *size) initLoopMax = *size;
-       // Detect high and lows
-       //25% clip in case highs and lows aren't clipped [marshmellow]
-       int high, low;
-       if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) 
-               return -1; //just noise
-
-       // if clean clipped waves detected run alternate demod
-       if (DetectCleanAskWave(BinStream, *size, high, low))
-               return cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
-
-       int lastBit;  //set first clock check - can go negative
-       size_t i, errCnt = 0, bitnum = 0;     //output counter
-       uint8_t midBit = 0;
-       size_t MaxBits = 1024;
-       lastBit = start - *clk;
-
-       for (i = start; i < *size; ++i) {
-               if (i - lastBit > *clk){
-                       if (BinStream[i] >= high) {
-                               BinStream[bitnum++] = *invert;
-                       } else if (BinStream[i] <= low) {
-                               BinStream[bitnum++] = *invert ^ 1;
-                       } else {
-                               if (bitnum > 0) {
-                                       BinStream[bitnum++]=77;
-                                       errCnt++;                                               
-                               } 
-                       }
-                       midBit = 0;
-                       lastBit += *clk;
-               } else if (i-lastBit > (*clk/2) && midBit == 0){
-                       if (BinStream[i] >= high) {
-                               BinStream[bitnum++] = *invert;
-                       } else if (BinStream[i] <= low) {
-                               BinStream[bitnum++] = *invert ^ 1;
-                       } else {
-
-                               BinStream[bitnum] = BinStream[bitnum-1];
-                               bitnum++;
-                       }
-                       midBit = 1;
-               }
-               if (bitnum >= MaxBits) break;
-       }
-       *size = bitnum;
-       return errCnt;
-}
-
+// by marshmellow

 // demod gProxIIDemod 
 // error returns as -x 
 // success returns start position in BitStream
 // demod gProxIIDemod 
 // error returns as -x 
 // success returns start position in BitStream


@@ -686,12 +633,13 @@ int PyramiddemodFSK(uint8_t *dest, size_t *size)
        return (int)startIdx;
 }
 
        return (int)startIdx;
 }
 

-
-uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, int high, int low)
+// by marshmellow
+// to detect a wave that has heavily clipped (clean) samples
+uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)

 {
        uint16_t allPeaks=1;
        uint16_t cntPeaks=0;
 {
        uint16_t allPeaks=1;
        uint16_t cntPeaks=0;

-       size_t loopEnd = 572;
+       size_t loopEnd = 512+60;

        if (loopEnd > size) loopEnd = size;
        for (size_t i=60; i<loopEnd; i++){
                if (dest[i]>low && dest[i]<high) 
        if (loopEnd > size) loopEnd = size;
        for (size_t i=60; i<loopEnd; i++){
                if (dest[i]>low && dest[i]<high) 


@@ -707,53 +655,39 @@ uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, int high, int low)
 
 // by marshmellow
 // to help detect clocks on heavily clipped samples
 
 // by marshmellow
 // to help detect clocks on heavily clipped samples

-// based on counts between zero crossings
-int DetectStrongAskClock(uint8_t dest[], size_t size)
+// based on count of low to low
+int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)

 {
 {

-       int clk[]={0,8,16,32,40,50,64,100,128};
-       size_t idx = 40;
-       uint8_t high=0;
-       size_t cnt = 0;
-       size_t highCnt = 0;
-       size_t highCnt2 = 0;
-       for (;idx < size; idx++){
-               if (dest[idx]>128) {
-                       if (!high){
-                               high=1;
-                               if (cnt > highCnt){
-                                       if (highCnt != 0) highCnt2 = highCnt;
-                                       highCnt = cnt;
-                               } else if (cnt > highCnt2) {
-                                       highCnt2 = cnt;
-                               }
-                               cnt=1;
-                       } else {
-                               cnt++;
-                       }
-               } else if (dest[idx] <= 128){
-                       if (high) {
-                               high=0;
-                               if (cnt > highCnt) {
-                                       if (highCnt != 0) highCnt2 = highCnt;
-                                       highCnt = cnt;
-                               } else if (cnt > highCnt2) {
-                                       highCnt2 = cnt;
-                               }
-                               cnt=1;
-                       } else {
-                               cnt++;
-                       }
-               }
+       uint8_t fndClk[] = {8,16,32,40,50,64,128};
+       size_t startwave;
+       size_t i = 0;
+       size_t minClk = 255;
+               // get to first full low to prime loop and skip incomplete first pulse
+       while ((dest[i] < high) && (i < size))
+               ++i;
+       while ((dest[i] > low) && (i < size))
+               ++i;
+
+       // loop through all samples
+       while (i < size) {
+               // measure from low to low
+               while ((dest[i] > low) && (i < size))
+                       ++i;
+               startwave= i;
+               while ((dest[i] < high) && (i < size))
+                       ++i;
+               while ((dest[i] > low) && (i < size))
+                       ++i;
+               //get minimum measured distance
+               if (i-startwave < minClk && i < size)
+                       minClk = i - startwave;

        }
        }

-       uint8_t tol;
-       for (idx=8; idx>0; idx--){
-               tol = clk[idx]/8;
-               if (clk[idx] >= highCnt - tol && clk[idx] <= highCnt + tol)
-                       return clk[idx];
-               if (clk[idx] >= highCnt2 - tol && clk[idx] <= highCnt2 + tol)
-                       return clk[idx];
+       // set clock
+       for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
+               if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
+                       return fndClk[clkCnt];

        }
        }

-       return -1;
+       return 0;

 }
 
 // by marshmellow
 }
 
 // by marshmellow


@@ -763,15 +697,15 @@ int DetectStrongAskClock(uint8_t dest[], size_t size)
 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 {
        size_t i=1;
 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 {
        size_t i=1;

-       uint8_t clk[]={255,8,16,32,40,50,64,100,128,255};
+       uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
+       uint8_t clkEnd = 9;

        uint8_t loopCnt = 255;  //don't need to loop through entire array...
        uint8_t loopCnt = 255;  //don't need to loop through entire array...

-       if (size==0) return -1;
-       if (size <= loopCnt) loopCnt = size-1; //not enough samples
+       if (size <= loopCnt) return -1; //not enough samples

 
        //if we already have a valid clock
        uint8_t clockFnd=0;
 
        //if we already have a valid clock
        uint8_t clockFnd=0;

-       for (;i<9;++i)
-               if (clk[i] == *clock) clockFnd=i;
+       for (;i<clkEnd;++i)
+               if (clk[i] == *clock) clockFnd = i;

                //clock found but continue to find best startpos
 
        //get high and low peak
                //clock found but continue to find best startpos
 
        //get high and low peak


@@ -779,37 +713,45 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
        if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
        
        //test for large clean peaks
        if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
        
        //test for large clean peaks

-       if (DetectCleanAskWave(dest, size, peak, low)==1){
-               int ans = DetectStrongAskClock(dest, size);
-               for (i=8; i>1; i--){
-                       if (clk[i] == ans) {
-                               *clock = ans;
-                               clockFnd = i;
-                               break; //clock found but continue to find best startpos
+       if (!clockFnd){
+               if (DetectCleanAskWave(dest, size, peak, low)==1){
+                       int ans = DetectStrongAskClock(dest, size, peak, low);
+                       for (i=clkEnd-1; i>0; i--){
+                               if (clk[i] == ans) {
+                                       *clock = ans;
+                                       //clockFnd = i;
+                                       return 0;  // for strong waves i don't use the 'best start position' yet...
+                                       //break; //clock found but continue to find best startpos [not yet]
+                               }

                        }
                }
        }
                        }
                }
        }

+       

        uint8_t ii;
        uint8_t clkCnt, tol = 0;
        uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
        uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
        size_t errCnt = 0;
        size_t arrLoc, loopEnd;
        uint8_t ii;
        uint8_t clkCnt, tol = 0;
        uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
        uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
        size_t errCnt = 0;
        size_t arrLoc, loopEnd;

-       //test each valid clock from smallest to greatest to see which lines up
-       uint8_t clkEnd=9;
-       if (clockFnd>0) clkEnd=clockFnd+1;
-       else clockFnd=1;

 
 

-       for(clkCnt=clockFnd; clkCnt < clkEnd; clkCnt++){
-               if (clk[clkCnt] == 32){
+       if (clockFnd>0) {
+               clkCnt = clockFnd;
+               clkEnd = clockFnd+1;
+       }
+       else clkCnt=1;
+
+       //test each valid clock from smallest to greatest to see which lines up
+       for(; clkCnt < clkEnd; clkCnt++){
+               if (clk[clkCnt] <= 32){

                        tol=1;
                }else{
                        tol=0;
                }
                        tol=1;
                }else{
                        tol=0;
                }

-               if (!maxErr && loopCnt>clk[clkCnt]*3) loopCnt=clk[clkCnt]*3;
+               //if no errors allowed - keep start within the first clock
+               if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;

                bestErr[clkCnt]=1000;
                //try lining up the peaks by moving starting point (try first few clocks)
                bestErr[clkCnt]=1000;
                //try lining up the peaks by moving starting point (try first few clocks)

-               for (ii=0; ii < loopCnt-tol-clk[clkCnt]; ii++){
+               for (ii=0; ii < loopCnt; ii++){

                        if (dest[ii] < peak && dest[ii] > low) continue;
 
                        errCnt=0;
                        if (dest[ii] < peak && dest[ii] > low) continue;
 
                        errCnt=0;


@@ -824,11 +766,11 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
                                        errCnt++;
                                }
                        }
                                        errCnt++;
                                }
                        }

-                       //if we found no errors then we can stop here
+                       //if we found no errors then we can stop here and a low clock (common clocks)

                        //  this is correct one - return this clock
                                        //PrintAndLog("DEBUG: clk %d, err %d, ii %d, i %d",clk[clkCnt],errCnt,ii,i);
                        //  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) {
-                               *clock = clk[clkCnt];
+                       if(errCnt==0 && clkCnt<7) { 
+                               if (!clockFnd) *clock = clk[clkCnt];

                                return ii;
                        }
                        //if we found errors see if it is lowest so far and save it as best run
                                return ii;
                        }
                        //if we found errors see if it is lowest so far and save it as best run


@@ -838,9 +780,9 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
                        }
                }
        }
                        }
                }
        }

-       uint8_t iii=0;
+       uint8_t iii;

        uint8_t best=0;
        uint8_t best=0;

-       for (iii=0; iii<8; ++iii){
+       for (iii=1; iii<clkEnd; ++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 (bestErr[iii] < bestErr[best]){
                        if (bestErr[iii] == 0) bestErr[iii]=1;
                        // current best bit to error ratio     vs  new bit to error ratio


@@ -849,8 +791,8 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
                        }
                }
        }
                        }
                }
        }

-       if (bestErr[best] > maxErr) return -1;
-       *clock = clk[best];
+       //if (bestErr[best] > maxErr) return -1;
+       if (!clockFnd) *clock = clk[best];

        return bestStart[best];
 }
 
        return bestStart[best];
 }
 


@@ -1029,7 +971,7 @@ void psk1TOpsk2(uint8_t *BitStream, size_t size)
        size_t i=1;
        uint8_t lastBit=BitStream[0];
        for (; i<size; i++){
        size_t i=1;
        uint8_t lastBit=BitStream[0];
        for (; i<size; i++){

-               if (BitStream[i]==77){
+               if (BitStream[i]==7){

                        //ignore errors
                } else if (lastBit!=BitStream[i]){
                        lastBit=BitStream[i];
                        //ignore errors
                } else if (lastBit!=BitStream[i]){
                        lastBit=BitStream[i];


@@ -1222,7 +1164,7 @@ int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int maxErr)
                        if (ignoreCnt == 0){
                                bitHigh = 0;
                                if (errBitHigh == 1){
                        if (ignoreCnt == 0){
                                bitHigh = 0;
                                if (errBitHigh == 1){

-                                       dest[bitnum++] = 77;
+                                       dest[bitnum++] = 7;

                                        errCnt++;
                                }
                                errBitHigh=0;
                                        errCnt++;
                                }
                                errBitHigh=0;


@@ -1497,7 +1439,7 @@ int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
                                                //noise after a phase shift - ignore
                                        } else { //phase shift before supposed to based on clock
                                                errCnt++;
                                                //noise after a phase shift - ignore
                                        } else { //phase shift before supposed to based on clock
                                                errCnt++;

-                                               dest[numBits++] = 77;
+                                               dest[numBits++] = 7;

                                        }
                                } else if (i+1 > lastClkBit + *clock + tol + fc){
                                        lastClkBit += *clock; //no phase shift but clock bit
                                        }
                                } else if (i+1 > lastClkBit + *clock + tol + fc){
                                        lastClkBit += *clock; //no phase shift but clock bit