Call to GetClock had wrong number of inparameters

[proxmark3-svn] / common / lfdemod.c

diff --git a/common/lfdemod.c b/common/lfdemod.c
index 4a80a10c7b715341648d4014e746d11ca8fa6fbf..88a250d87efd105fa85f70ef919c2fd89585a75d 100644 (file)
--- a/common/lfdemod.c
+++ b/common/lfdemod.c
@@ -12,6 +12,18 @@
 #include <string.h>
 #include "lfdemod.h"
 
 #include <string.h>
 #include "lfdemod.h"
 

+
+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;
+       }
+       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)
 //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)


@@ -29,57 +41,82 @@ int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi
        return 1;
 }
 
        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);
+       }
+  //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
 //by marshmellow
 //takes 1s and 0s and searches for EM410x format - output EM ID

-uint64_t Em410xDecode(uint8_t *BitStream, size_t size)
+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[10]>1){  //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) < 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=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; //try 5 times
-                                       resetCnt++;
-                                       goto restart;//continue;
-                               }
-                       }
-                       //skip last 5 bit parity test for simplicity.
-                       return lo;
-               }else{
-                       idx++;
-               }
-       }
-       return 0;
+  //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
 }
 
 //by marshmellow


@@ -89,10 +126,12 @@ uint64_t Em410xDecode(uint8_t *BitStream, size_t size)
 int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
 {
        int i;
 int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
 {
        int i;

+       int clk2=*clk;

        *clk=DetectASKClock(BinStream, *size, *clk); //clock default
 
        *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;
        if (*invert != 0 && *invert != 1) *invert=0;
        uint32_t initLoopMax = 200;
        if (initLoopMax > *size) initLoopMax=*size;


@@ -106,7 +145,7 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
        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
        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;
        int iii = 0;
        uint32_t gLen = *size;
        if (gLen > 3000) gLen=3000;


@@ -198,6 +237,22 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
        return bestErrCnt;
 }
 
        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
 //by marshmellow
 //take 10 and 01 and manchester decode
 //run through 2 times and take least errCnt


@@ -245,7 +300,6 @@ int manrawdecode(uint8_t * BitStream, size_t *size)
        return 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 invert)
 //by marshmellow
 //take 01 or 10 = 0 and 11 or 00 = 1
 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)


@@ -282,8 +336,8 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
        //uint8_t BitStream[502] = {0};
 
        //HACK: if clock not detected correctly - default
        //uint8_t BitStream[502] = {0};
 
        //HACK: if clock not detected correctly - default

-       if (*clk<8) *clk =64;
-       if (*clk<32 && clk2==0) *clk=32;
+       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;
        if (*invert != 0 && *invert != 1) *invert =0;
        uint32_t initLoopMax = 200;
        if (initLoopMax > *size) initLoopMax=*size;


@@ -317,30 +371,20 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
                        for (i = iii; i < *size; ++i) {
                                if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
                                        lastBit+=*clk;
                        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;
                                        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;
                                        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;
                                } 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;
                                } 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
 
                                } else {
                                        //mid value found or no bar supposed to be here
 


@@ -348,16 +392,11 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
                                                //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);
                                                //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;
 
                                                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;
                                                }
                                        }
                                                        break;
                                                }
                                        }


@@ -533,56 +572,69 @@ int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t
        size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow);
        return size;
 }
        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
 // 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 idx=0; //, found=0; //size=0,
+  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
+
+  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
        // 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)
 }
 
 uint32_t bytebits_to_byte(uint8_t* src, size_t numbits)


@@ -598,20 +650,12 @@ uint32_t bytebits_to_byte(uint8_t* src, size_t numbits)
 
 int IOdemodFSK(uint8_t *dest, size_t size)
 {
 
 int IOdemodFSK(uint8_t *dest, size_t size)
 {

-       static const uint8_t THRESHOLD = 129;
-       uint32_t idx=0;
+       if (justNoise(dest, size)) return -1;

        //make sure buffer has data
        //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
        // 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
        //|           |           |           |           |           |           |
        //Index map
        //0           10          20          30          40          50          60
        //|           |           |           |           |           |           |


@@ -621,31 +665,17 @@ int IOdemodFSK(uint8_t *dest, size_t size)
        //
        //XSF(version)facility:codeone+codetwo
        //Handle the data
        //
        //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 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);
+       return -5;

 }
 
 // by marshmellow
 }
 
 // by marshmellow


@@ -673,65 +703,45 @@ size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t p
 
 // by marshmellow
 // FSK Demod then try to locate an AWID ID
 
 // by marshmellow
 // FSK Demod then try to locate an AWID ID

-int AWIDdemodFSK(uint8_t *dest, size_t size)
+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;
+       //make sure buffer has enough data
+       if (*size < 96*50) return -1;
+
+       if (justNoise(dest, *size)) return -2;

 
        // FSK demodulator
 
        // 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;
+       *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
 }
 
 // by marshmellow
 // FSK Demod then try to locate an Farpointe Data (pyramid) ID

-int PyramiddemodFSK(uint8_t *dest, size_t size)
+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
   //make sure buffer has data

-  if (size < 128*50) return -5;
+  if (*size < 128*50) return -5;
+

   //test samples are not just noise
   //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;
+  if (justNoise(dest, *size)) return -1;

 
   // FSK demodulator
 
   // 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;
+  *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
 }
 
 // by marshmellow


@@ -739,64 +749,67 @@ int PyramiddemodFSK(uint8_t *dest, size_t size)
 // maybe somehow adjust peak trimming value based on samples to fix?
 int DetectASKClock(uint8_t dest[], size_t size, int clock)
 {
 // 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 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;
+  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
-       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 < 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<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]) ){
-                               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
 }
 
 //by marshmellow


@@ -809,7 +822,7 @@ int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
        if (size<loopCnt) loopCnt = size;
 
        //if we already have a valid clock quit
        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
                if (clk[i] == clock) return clock;
 
        //get high and low peak


@@ -822,11 +835,11 @@ int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
        uint8_t tol = 0;
        int peakcnt=0;
        int errCnt=0;
        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
        //test each valid clock from smallest to greatest to see which lines up

-       for(clkCnt=0; clkCnt < 6; ++clkCnt){
-               if (clk[clkCnt] >= 32){
+       for(clkCnt=0; clkCnt < 7; ++clkCnt){
+               if (clk[clkCnt] <= 32){

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


@@ -837,7 +850,7 @@ int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
                                errCnt=0;
                                peakcnt=0;
                                // now that we have the first one lined up test rest of wave array
                                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){
                                        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){


@@ -876,7 +889,7 @@ int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
        return clk[best];
 }
 
        return clk[best];
 }
 

-//by marshmellow (attempt to get rid of high immediately after a low)
+// by marshmellow (attempt to get rid of high immediately after a low)

 void pskCleanWave(uint8_t *BitStream, size_t size)
 {
        int i;
 void pskCleanWave(uint8_t *BitStream, size_t size)
 {
        int i;


@@ -912,9 +925,26 @@ void pskCleanWave(uint8_t *BitStream, size_t size)
        return;
 }
 
        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 indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
 {
        //26 bit 40134 format  (don't know other formats)


@@ -977,11 +1007,11 @@ int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
        return 1;
 }
 
        return 1;
 }
 

-
-//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
+// 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)
 {
 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;
        pskCleanWave(dest,*size);
        int clk2 = DetectpskNRZClock(dest, *size, *clk);
        *clk=clk2;


@@ -1000,7 +1030,6 @@ int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
        uint32_t bestStart = *size;
        uint32_t maxErr = (*size/1000);
        uint32_t bestErrCnt = maxErr;
        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;
        uint8_t curBit=0;
        uint8_t bitHigh=0;
        uint8_t ignorewin=*clk/8;


@@ -1111,98 +1140,65 @@ int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
        return errCnt;
 }
 
        return errCnt;
 }
 

-

 //by marshmellow
 //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)
+//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)

 {
 {

-  // 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 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 rfLensFnd = 0;

-  uint8_t lastBit=0;
-  uint8_t curBit=0;

   uint8_t lastFCcnt=0;
   uint8_t lastFCcnt=0;

-  uint32_t errCnt=0;

   uint32_t fcCounter = 0;
   uint32_t fcCounter = 0;

-  uint32_t rfCounter = 0;
+  uint16_t rfCounter = 0;

   uint8_t firstBitFnd = 0;
   uint8_t firstBitFnd = 0;

-  int i;
-  
+  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
   // prime i to first up transition

-  for (i = 1; i < size; i++)
-    if (BitStream[i]>=zeroC && BitStream[i-1]<zeroC)
+  for (i = 1; i < size-1; i++)
+    if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])

       break;
 
       break;
 

-  for (; i < size; i++){
-    curBit = BitStream[i];
-    lastBit = BitStream[i-1];
-    if (lastBit<zeroC && curBit >= zeroC){
-      // new up transition
+  for (; i < size-1; i++){
+    if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]){
+      // new peak 

       fcCounter++;
       rfCounter++;
       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++;
+      // 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<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;
+      //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;

             }
             }

-          } 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 (rfCounter>0 && rfLensFnd<15){
+            //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+            rfCnts[rfLensFnd]++;
+            rfLens[rfLensFnd++]=rfCounter;

           }
           }

+        } else {
+          firstBitFnd++;

         }
         }

-        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++;
+        rfCounter=0;
+        lastFCcnt=fcCounter;

       }
       }

-      // reset counter

       fcCounter=0;
     } else {
       // count sample
       fcCounter=0;
     } else {
       // count sample


@@ -1210,46 +1206,30 @@ uint32_t countFC(uint8_t *BitStream, size_t size)
       rfCounter++;
     }
   }
       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;
+  uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;

 
 

-  // 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;
-    }
+  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?)
     //get highest 2 RF values  (might need to get more values to compare or compare all?)

-    if (rfLens[i]>rfLens[rfHighest]){
+    if (rfCnts[i]>rfCnts[rfHighest]){

       rfHighest3=rfHighest2;
       rfHighest2=rfHighest;
       rfHighest=i;
       rfHighest3=rfHighest2;
       rfHighest2=rfHighest;
       rfHighest=i;

-    } else if(rfLens[i]>rfLens[rfHighest2]){
+    } else if(rfCnts[i]>rfCnts[rfHighest2]){

       rfHighest3=rfHighest2;
       rfHighest2=i;
       rfHighest3=rfHighest2;
       rfHighest2=i;

-    } else if(rfLens[i]>rfLens[rfHighest3]){
+    } else if(rfCnts[i]>rfCnts[rfHighest3]){

       rfHighest3=i;
     }
       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]; 
+  }  
+  // 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
   // loop to find the highest clock that has a remainder less than the tolerance

-  //   compare samples counted divided by 
+  //   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){
   int ii=7;
   for (; ii>=0; ii--){
     if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){


@@ -1261,19 +1241,90 @@ uint32_t countFC(uint8_t *BitStream, size_t size)
     }
   }
 
     }
   }
 

-  if (ii<0) ii=7; // oops we went too far
+  if (ii<0) return 0; // oops we went too far

 
 

-  // TODO: take top 3 answers and compare to known Field clocks to get top 2
+  return clk[ii];
+}

 
 

-  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]);
-  //
+//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]){
   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]));    
+    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;
 }
   return fcs;
 }