]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - common/lfdemod.c
Merge pull request #56 from iceman1001/feature
[proxmark3-svn] / common / lfdemod.c
index 144783198e1684a8be432a5abdcc5f5d296c5147..88a250d87efd105fa85f70ef919c2fd89585a75d 100644 (file)
 //-----------------------------------------------------------------------------
-// Copyright (C) 2014 
+// Copyright (C) 2014
 //
 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
 // at your option, any later version. See the LICENSE.txt file for the text of
 // the license.
 //-----------------------------------------------------------------------------
-// Low frequency commands
+// Low frequency demod/decode commands
 //-----------------------------------------------------------------------------
 
 #include <stdlib.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
-//takes 1s and 0s and searches for EM410x format - output EM ID
-uint64_t Em410xDecode(uint8_t *BitStream,uint32_t BitLen)
+//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)
 {
-    //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
-    //  otherwise could be a void with no arguments
-    //set defaults
-    int high=0, low=128;
-    uint64_t lo=0; //hi=0,
-
-    uint32_t i = 0;
-    uint32_t initLoopMax = 65;
-    if (initLoopMax>BitLen) initLoopMax=BitLen;
-
-    for (;i < initLoopMax; ++i) //65 samples should be plenty to find high and low values
-    {
-        if (BitStream[i] > high)
-            high = BitStream[i];
-        else if (BitStream[i] < low)
-            low = BitStream[i];
-    }
-    if (((high !=1)||(low !=0))){  //allow only 1s and 0s
-        // PrintAndLog("no data found");
-        return 0;
-    }
-    uint8_t parityTest=0;
-    // 111111111 bit pattern represent start of frame
-    uint8_t frame_marker_mask[] = {1,1,1,1,1,1,1,1,1};
-    uint32_t idx = 0;
-    uint32_t ii=0;
-    uint8_t resetCnt = 0;
-    while( (idx + 64) < BitLen) {
-restart:
-        // search for a start of frame marker
-        if ( memcmp(BitStream+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
-        { // frame marker found
-            idx+=9;//sizeof(frame_marker_mask);
-            for (i=0; i<10;i++){
-                for(ii=0; ii<5; ++ii){
-                    parityTest += BitStream[(i*5)+ii+idx];
-                }
-                if (parityTest== ((parityTest>>1)<<1)){
-                    parityTest=0;
-                    for (ii=0; ii<4;++ii){
-                        //hi = (hi<<1)|(lo>>31);
-                        lo=(lo<<1LL)|(BitStream[(i*5)+ii+idx]);
-                    }
-                    //PrintAndLog("DEBUG: EM parity passed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d,lo: %d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1],lo);
-                }else {//parity failed
-                    //PrintAndLog("DEBUG: EM parity failed parity val: %d, i:%d, ii:%d,idx:%d, Buffer: %d%d%d%d%d",parityTest,i,ii,idx,BitStream[idx+ii+(i*5)-5],BitStream[idx+ii+(i*5)-4],BitStream[idx+ii+(i*5)-3],BitStream[idx+ii+(i*5)-2],BitStream[idx+ii+(i*5)-1]);
-                    parityTest=0;
-                    idx-=8;
-                    if (resetCnt>5)return 0;
-                    resetCnt++;
-                    goto restart;//continue;
-                }
-            }
-            //skip last 5 bit parity test for simplicity.
-            return lo;
-        }else{
-            idx++;
-        }
+       *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
+// 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
+uint64_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx)
+{
+  //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
+  //  otherwise could be a void with no arguments
+  //set defaults
+  uint64_t lo=0;
+  uint32_t i = 0;
+  if (BitStream[1]>1){  //allow only 1s and 0s
+    // PrintAndLog("no data found");
     return 0;
+  }
+  // 111111111 bit pattern represent start of frame
+  uint8_t preamble[] = {1,1,1,1,1,1,1,1,1};
+  uint32_t idx = 0;
+  uint32_t parityBits = 0;
+  uint8_t errChk = 0;
+  *startIdx = 0;
+  for (uint8_t extraBitChk=0; extraBitChk<5; extraBitChk++){
+    errChk = preambleSearch(BitStream+extraBitChk+*startIdx, preamble, sizeof(preamble), size, startIdx);
+    if (errChk == 0) return 0;
+    idx = *startIdx + 9;
+    for (i=0; i<10;i++){ //loop through 10 sets of 5 bits (50-10p = 40 bits)
+      parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
+      //check even parity
+      if (parityTest(parityBits, 5, 0) == 0){
+        //parity failed try next bit (in the case of 1111111111) but last 9 = preamble
+        startIdx++;
+        errChk = 0;
+        break;
+      }
+      for (uint8_t ii=0; ii<4; ii++){
+        lo = (lo << 1LL) | (BitStream[(i*5)+ii+idx]);
+      }
+    }
+    if (errChk != 0) return lo;
+    //skip last 5 bit parity test for simplicity.
+    // *size = 64;
+  }
+  return 0;
 }
 
 //by marshmellow
 //takes 2 arguments - clock and invert both as integers
-//attempts to demodulate ask while decoding manchester 
+//attempts to demodulate ask while decoding manchester
 //prints binary found and saves in graphbuffer for further commands
-int askmandemod(uint8_t * BinStream,uint32_t *BitLen,int *clk, int *invert)
+int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
 {
-    int i;
-    int high = 0, low = 128;
-    *clk=DetectASKClock(BinStream,(size_t)*BitLen,*clk); //clock default
-
-    if (*clk<8) *clk =64;
-    if (*clk<32) *clk=32;
-    if (*invert != 0 && *invert != 1) *invert=0;
-    uint32_t initLoopMax = 200;
-    if (initLoopMax>*BitLen) initLoopMax=*BitLen;
-    // Detect high and lows
-    for (i = 0; i < initLoopMax; ++i) //200 samples should be enough to find high and low values
-    {
-        if (BinStream[i] > high)
-            high = BinStream[i];
-        else if (BinStream[i] < low)
-            low = BinStream[i];
-    }
-    if ((high < 158) ){  //throw away static
-        //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;
-
-    //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
-    int lastBit = 0;  //set first clock check
-    uint32_t bitnum = 0;     //output counter
-    int tol = 0;  //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
-    if (*clk==32)tol=1;    //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
-    int iii = 0;
-    uint32_t gLen = *BitLen;
-    if (gLen > 3000) gLen=3000;
-    uint8_t errCnt =0;
-    uint32_t bestStart = *BitLen;
-    uint32_t bestErrCnt = (*BitLen/1000);
-    uint32_t maxErr = (*BitLen/1000);
-    //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
-            for (i = iii; i < *BitLen; ++i) {
-                if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
-                    lastBit+=*clk;
-                } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
-                    //low found and we are expecting a bar
-                    lastBit+=*clk;
-                } else {
-                    //mid value found or no bar supposed to be here
-                    if ((i-lastBit)>(*clk+tol)){
-                        //should have hit a high or low based on clock!!
-
-                        //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);
-
-                        errCnt++;
-                        lastBit+=*clk;//skip over until hit too many errors
-                        if (errCnt>(maxErr)) break;  //allow 1 error for every 1000 samples else start over
-                    }
-                }
-                if ((i-iii) >(400 * *clk)) break; //got plenty of bits
-            }
-            //we got more than 64 good bits and not all errors
-            if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<maxErr)) {
-                //possible good read
-                if (errCnt==0){
-                    bestStart=iii;
-                    bestErrCnt=errCnt;
-                    break;  //great read - finish
-                }
-                if (errCnt<bestErrCnt){  //set this as new best run
-                    bestErrCnt=errCnt;
-                    bestStart = iii;
-                }
-            }
-        }
-    }
-    if (bestErrCnt<maxErr){
-        //best run is good enough set to best run and set overwrite BinStream
-        iii=bestStart;
-        lastBit=bestStart-*clk;
-        bitnum=0;
-        for (i = iii; i < *BitLen; ++i) {
-            if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
-                lastBit+=*clk;
-                BinStream[bitnum] =  *invert;
-                bitnum++;
-            } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
-                //low found and we are expecting a bar
-                lastBit+=*clk;
-                BinStream[bitnum] = 1-*invert;
-                bitnum++;
-            } else {
-                //mid value found or no bar supposed to be here
-                if ((i-lastBit)>(*clk+tol)){
-                    //should have hit a high or low based on clock!!
-
-                    //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;
-        }
-        *BitLen=bitnum;
-    } else{
-        *invert=bestStart;
-        *clk=iii;
-        return -1;
-    }
-    return bestErrCnt;
+       int i;
+       int clk2=*clk;
+       *clk=DetectASKClock(BinStream, *size, *clk); //clock default
+
+       // if autodetected too low then adjust  //MAY NEED ADJUSTMENT
+       if (clk2==0 && *clk<8) *clk =64;
+       if (clk2==0 && *clk<32) *clk=32;
+       if (*invert != 0 && *invert != 1) *invert=0;
+       uint32_t initLoopMax = 200;
+       if (initLoopMax > *size) initLoopMax=*size;
+       // Detect high and lows
+       // 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);
+       int lastBit = 0;  //set first clock check
+       uint32_t bitnum = 0;     //output counter
+       int tol = 0;  //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
+       if (*clk<=32)tol=1;    //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
+       int iii = 0;
+       uint32_t gLen = *size;
+       if (gLen > 3000) gLen=3000;
+       uint8_t errCnt =0;
+       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
+       for (iii=0; iii < gLen; ++iii){
+               if ((BinStream[iii] >= high) || (BinStream[iii] <= low)){
+                       lastBit=iii-*clk;
+                       errCnt=0;
+                       // loop through to see if this start location works
+                       for (i = iii; i < *size; ++i) {
+                               if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
+                                       lastBit+=*clk;
+                               } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
+                                       //low found and we are expecting a bar
+                                       lastBit+=*clk;
+                               } else {
+                                       //mid value found or no bar supposed to be here
+                                       if ((i-lastBit)>(*clk+tol)){
+                                               //should have hit a high or low based on clock!!
+
+                                               //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);
+
+                                               errCnt++;
+                                               lastBit+=*clk;//skip over until hit too many errors
+                                               if (errCnt>(maxErr)) break;  //allow 1 error for every 1000 samples else start over
+                                       }
+                               }
+                               if ((i-iii) >(400 * *clk)) break; //got plenty of bits
+                       }
+                       //we got more than 64 good bits and not all errors
+                       if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<maxErr)) {
+                               //possible good read
+                               if (errCnt==0){
+                                       bestStart=iii;
+                                       bestErrCnt=errCnt;
+                                       break;  //great read - finish
+                               }
+                               if (errCnt<bestErrCnt){  //set this as new best run
+                                       bestErrCnt=errCnt;
+                                       bestStart = iii;
+                               }
+                       }
+               }
+       }
+       if (bestErrCnt<maxErr){
+               //best run is good enough set to best run and set overwrite BinStream
+               iii=bestStart;
+               lastBit = bestStart - *clk;
+               bitnum=0;
+               for (i = iii; i < *size; ++i) {
+                       if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
+                               lastBit += *clk;
+                               BinStream[bitnum] = *invert;
+                               bitnum++;
+                       } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
+                               //low found and we are expecting a bar
+                               lastBit+=*clk;
+                               BinStream[bitnum] = 1-*invert;
+                               bitnum++;
+                       } else {
+                               //mid value found or no bar supposed to be here
+                               if ((i-lastBit)>(*clk+tol)){
+                                       //should have hit a high or low based on clock!!
+
+                                       //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{
+               *invert=bestStart;
+               *clk=iii;
+               return -1;
+       }
+       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
-int manrawdecode(uint8_t * BitStream, int *bitLen)
+int manrawdecode(uint8_t * BitStream, size_t *size)
 {
-    int bitnum=0;
-    int errCnt =0;
-    int i=1;
-    int bestErr = 1000;
-    int bestRun = 0;
-    int ii=1;
-    for (ii=1;ii<3;++ii){
-        i=1;
-        for (i=i+ii;i<*bitLen-2;i+=2){
-            if(BitStream[i]==1 && (BitStream[i+1]==0)){
-            } else if((BitStream[i]==0)&& BitStream[i+1]==1){
-            } else {
-                errCnt++;
-            }
-            if(bitnum>300) break;
-        }
-        if (bestErr>errCnt){
-            bestErr=errCnt;
-            bestRun=ii;
-        }
-        errCnt=0;
-    }
-    errCnt=bestErr;
-    if (errCnt<20){
-        ii=bestRun;
-        i=1;
-        for (i=i+ii;i<*bitLen-2;i+=2){
-            if(BitStream[i]==1 && (BitStream[i+1]==0)){
-                BitStream[bitnum++]=0;
-            } else if((BitStream[i]==0)&& BitStream[i+1]==1){
-                BitStream[bitnum++]=1;
-            } else {
-                BitStream[bitnum++]=77;
-                //errCnt++;
-            }
-            if(bitnum>300) break;
-        }
-        *bitLen=bitnum;
-    }
-    return errCnt;
+       int bitnum=0;
+       int errCnt =0;
+       int i=1;
+       int bestErr = 1000;
+       int bestRun = 0;
+       int ii=1;
+       for (ii=1;ii<3;++ii){
+               i=1;
+               for (i=i+ii;i<*size-2;i+=2){
+                       if(BitStream[i]==1 && (BitStream[i+1]==0)){
+                       } else if((BitStream[i]==0)&& BitStream[i+1]==1){
+                       } else {
+                               errCnt++;
+                       }
+                       if(bitnum>300) break;
+               }
+               if (bestErr>errCnt){
+                       bestErr=errCnt;
+                       bestRun=ii;
+               }
+               errCnt=0;
+       }
+       errCnt=bestErr;
+       if (errCnt<20){
+               ii=bestRun;
+               i=1;
+               for (i=i+ii;i < *size-2;i+=2){
+                       if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
+                               BitStream[bitnum++]=0;
+                       } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
+                               BitStream[bitnum++]=1;
+                       } else {
+                               BitStream[bitnum++]=77;
+                               //errCnt++;
+                       }
+                       if(bitnum>300) break;
+               }
+               *size=bitnum;
+       }
+       return errCnt;
 }
 
-
 //by marshmellow
 //take 01 or 10 = 0 and 11 or 00 = 1
-int BiphaseRawDecode(uint8_t * BitStream, int *bitLen, 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;
-    i=offset;
-    for (;i<*bitLen-2;i+=2){
-        if((BitStream[i]==1 && BitStream[i+1]==0)||(BitStream[i]==0 && BitStream[i+1]==1)){
-            BitStream[bitnum++]=1;
-        } else if((BitStream[i]==0 && BitStream[i+1]==0)||(BitStream[i]==1 && BitStream[i+1]==1)){
-            BitStream[bitnum++]=0;
-        } else {
-            BitStream[bitnum++]=77;
-            errCnt++;
-        }
-        if(bitnum>250) break;
-    }
-    *bitLen=bitnum;
-    return errCnt;
+       uint8_t bitnum=0;
+       uint32_t errCnt =0;
+       uint32_t i;
+       i=offset;
+       for (;i<*size-2; i+=2){
+               if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
+                       BitStream[bitnum++]=1^invert;
+               } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
+                       BitStream[bitnum++]=invert;
+               } else {
+                       BitStream[bitnum++]=77;
+                       errCnt++;
+               }
+               if(bitnum>250) break;
+       }
+       *size=bitnum;
+       return errCnt;
 }
 
 //by marshmellow
 //takes 2 arguments - clock and invert both as integers
 //attempts to demodulate ask only
 //prints binary found and saves in graphbuffer for further commands
-int askrawdemod(uint8_t *BinStream, int *bitLen,int *clk, int *invert)
+int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert)
 {
-    uint32_t i;
-    // int invert=0;  //invert default
-    int high = 0, low = 128;
-    *clk=DetectASKClock(BinStream,*bitLen,*clk); //clock default
-    uint8_t BitStream[502] = {0};
-
-    if (*clk<8) *clk =64;
-    if (*clk<32) *clk=32;
-    if (*invert != 0 && *invert != 1) *invert =0;
-    uint32_t initLoopMax = 200;
-    if (initLoopMax>*bitLen) initLoopMax=*bitLen;
-    // Detect high and lows
-    for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values
-    {
-        if (BinStream[i] > high)
-            high = BinStream[i];
-        else if (BinStream[i] < low)
-            low = BinStream[i];
-    }
-    if ((high < 158)){  //throw away static
-        //   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;
-
-    //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
-    int lastBit = 0;  //set first clock check
-    uint32_t bitnum = 0;     //output counter
-    uint8_t tol = 0;  //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
-    if (*clk==32)tol=1;    //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
-    uint32_t iii = 0;
-    uint32_t gLen = *bitLen;
-    if (gLen > 500) gLen=500;
-    uint8_t errCnt =0;
-    uint32_t bestStart = *bitLen;
-    uint32_t bestErrCnt = (*bitLen/1000);
-    uint8_t midBit=0;
-    //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;
-            //loop through to see if this start location works
-            for (i = iii; i < *bitLen; ++i) {
-                if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
-                    lastBit+=*clk;
-                    BitStream[bitnum] =  *invert;
-                    bitnum++;
-                    midBit=0;
-                } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
-                    //low found and we are expecting a bar
-                    lastBit+=*clk;
-                    BitStream[bitnum] = 1-*invert;
-                    bitnum++;
-                    midBit=0;
-                } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
-                    //mid bar?
-                    midBit=1;
-                    BitStream[bitnum]= 1-*invert;
-                    bitnum++;
-                } else if ((BinStream[i]>=high)&&(midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
-                    //mid bar?
-                    midBit=1;
-                    BitStream[bitnum]= *invert;
-                    bitnum++;
-                } else if ((i-lastBit)>((*clk/2)+tol)&&(midBit==0)){
-                    //no mid bar found
-                    midBit=1;
-                    BitStream[bitnum]= BitStream[bitnum-1];
-                    bitnum++;
-                } else {
-                    //mid value found or no bar supposed to be here
-
-                    if ((i-lastBit)>(*clk+tol)){
-                        //should have hit a high or low based on clock!!
-                        //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>((*bitLen/1000))){  //allow 1 error for every 1000 samples else start over
-                            errCnt=0;
-                            bitnum=0;//start over
-                            break;
-                        }
-                    }
-                }
-                if (bitnum>500) break;
-            }
-            //we got more than 64 good bits and not all errors
-            if ((bitnum > (64+errCnt)) && (errCnt<(*bitLen/1000))) {
-                //possible good read
-                if (errCnt==0) break;  //great read - finish
-                if (bestStart == iii) break;  //if current run == bestErrCnt run (after exhausted testing) then finish
-                if (errCnt<bestErrCnt){  //set this as new best run
-                    bestErrCnt=errCnt;
-                    bestStart = iii;
-                }
-            }
-        }
-        if (iii>=gLen){ //exhausted test
-            //if there was a ok test go back to that one and re-run the best run (then dump after that run)
-            if (bestErrCnt < (*bitLen/1000)) iii=bestStart;
-        }
-    }
-    if (bitnum>16){
+       uint32_t i;
+       // int invert=0;  //invert default
+       int clk2 = *clk;
+       *clk=DetectASKClock(BinStream, *size, *clk); //clock default
+       //uint8_t BitStream[502] = {0};
 
-        // PrintAndLog("Data start pos:%d, lastBit:%d, stop pos:%d, numBits:%d",iii,lastBit,i,bitnum);
-        //move BitStream back to BinStream
-        // ClearGraph(0);
-        for (i=0; i < bitnum; ++i){
-            BinStream[i]=BitStream[i];
-        }
-        *bitLen=bitnum;
-        // RepaintGraphWindow();
-        //output
-        // if (errCnt>0){
-        //   PrintAndLog("# Errors during Demoding (shown as 77 in bit stream): %d",errCnt);
-        // }
-        // PrintAndLog("ASK decoded bitstream:");
-        // Now output the bitstream to the scrollback by line of 16 bits
-        // printBitStream2(BitStream,bitnum);
-        //int errCnt=0;
-        //errCnt=manrawdemod(BitStream,bitnum);
-
-        //   Em410xDecode(Cmd);
-    } else return -1;
-    return errCnt;
+       //HACK: if clock not detected correctly - default
+       if (clk2==0 && *clk<8) *clk =64;
+       if (clk2==0 && *clk<32 && clk2==0) *clk=32;
+       if (*invert != 0 && *invert != 1) *invert =0;
+       uint32_t initLoopMax = 200;
+       if (initLoopMax > *size) initLoopMax=*size;
+       // Detect high and lows
+       //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);
+       int lastBit = 0;  //set first clock check
+       uint32_t bitnum = 0;     //output counter
+       uint8_t tol = 0;  //clock tolerance adjust - waves will be accepted as within the clock
+                         //  if they fall + or - this value + clock from last valid wave
+       if (*clk == 32) tol=1;    //clock tolerance may not be needed anymore currently set to
+                                 //  + or - 1 but could be increased for poor waves or removed entirely
+       uint32_t iii = 0;
+       uint32_t gLen = *size;
+       if (gLen > 500) gLen=500;
+       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 (iii=0; iii < gLen; ++iii){
+               if ((BinStream[iii]>=high) || (BinStream[iii]<=low)){
+                       lastBit=iii-*clk;
+                       //loop through to see if this start location works
+                       for (i = iii; i < *size; ++i) {
+                               if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
+                                       lastBit+=*clk;
+                                       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) && (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;
+                               } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
+                                       //no mid bar found
+                                       midBit=1;
+                               } 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);
+
+                                               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;
+                                                       break;
+                                               }
+                                       }
+                               }
+                               if ((i-iii)>(500 * *clk)) break; //got enough bits
+                       }
+                       //we got more than 64 good bits and not all errors
+                       if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<(*size/1000))) {
+                               //possible good read
+                               if (errCnt==0){
+                                       bestStart=iii;
+                                       bestErrCnt=errCnt;
+                                       break;  //great read - finish
+                               } 
+                               if (errCnt<bestErrCnt){  //set this as new best run
+                                       bestErrCnt=errCnt;
+                                       bestStart = iii;
+                               }
+                       }
+               }
+       }
+       if (bestErrCnt<maxErr){
+               //best run is good enough - set to best run and 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{
+               *invert=bestStart;
+               *clk=iii;
+               return -1;
+       }
+       return bestErrCnt;
 }
-//translate wave to 11111100000 (1 for each short wave 0 for each long wave) 
+//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
 {
-    uint32_t last_transition = 0;
-    uint32_t idx = 1;
-    uint32_t maxVal=0;
-    if (fchigh==0) fchigh=10;
-    if (fclow==0) fclow=8;
-    // we do care about the actual theshold value as sometimes near the center of the
-    // wave we may get static that changes direction of wave for one value
-    // if our value is too low it might affect the read.  and if our tag or
-    // antenna is weak a setting too high might not see anything. [marshmellow]
-    if (size<100) return 0;
-    for(idx=1; idx<100; idx++){
-        if(maxVal<dest[idx]) maxVal = dest[idx];
-    }
-    // set close to the top of the wave threshold with 25% margin for error
-    // less likely to get a false transition up there.
-    // (but have to be careful not to go too high and miss some short waves)
-    uint8_t threshold_value = (uint8_t)(((maxVal-128)*.75)+128);
-    // idx=1;
-    //uint8_t threshold_value = 127;
-
-    // sync to first lo-hi transition, and threshold
-
-    // Need to threshold first sample
-
-    if(dest[0] < threshold_value) dest[0] = 0;
-    else dest[0] = 1;
-
-    size_t numBits = 0;
-    // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
-    // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
-    // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
-    for(idx = 1; idx < size; idx++) {
-        // threshold current value
-
-        if (dest[idx] < threshold_value) dest[idx] = 0;
-        else dest[idx] = 1;
-
-        // Check for 0->1 transition
-        if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
-            if ((idx-last_transition)<(fclow-2)){            //0-5 = garbage noise
-                //do nothing with extra garbage
-            } else if ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves
-                dest[numBits]=1;
-            } else {                                                   //9+ = 10 waves
-                dest[numBits]=0;
-            }
-            last_transition = idx;
-            numBits++;
-        }
-    }
-    return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
+       uint32_t last_transition = 0;
+       uint32_t idx = 1;
+       //uint32_t maxVal=0;
+       if (fchigh==0) fchigh=10;
+       if (fclow==0) fclow=8;
+       //set the threshold close to 0 (graph) or 128 std to avoid static
+       uint8_t threshold_value = 123; 
+
+       // sync to first lo-hi transition, and threshold
+
+       // Need to threshold first sample
+
+       if(dest[0] < threshold_value) dest[0] = 0;
+       else dest[0] = 1;
+
+       size_t numBits = 0;
+       // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
+       // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
+       // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
+       for(idx = 1; idx < size; idx++) {
+               // threshold current value
+
+               if (dest[idx] < threshold_value) dest[idx] = 0;
+               else dest[idx] = 1;
+
+               // Check for 0->1 transition
+               if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
+                       if ((idx-last_transition)<(fclow-2)){            //0-5 = garbage noise
+                               //do nothing with extra garbage
+                       } else if ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves
+                               dest[numBits]=1;
+                       } else {                                                        //9+ = 10 waves
+                               dest[numBits]=0;
+                       }
+                       last_transition = idx;
+                       numBits++;
+               }
+       }
+       return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
 }
 
 uint32_t myround2(float f)
 {
-    if (f >= 2000) return 2000;//something bad happened
-    return (uint32_t) (f + (float)0.5);
+       if (f >= 2000) return 2000;//something bad happened
+       return (uint32_t) (f + (float)0.5);
 }
 
-//translate 11111100000 to 10 
-size_t aggregate_bits(uint8_t *dest,size_t size,  uint8_t rfLen, uint8_t maxConsequtiveBits, uint8_t invert,uint8_t fchigh,uint8_t fclow )// uint8_t h2l_crossing_value,uint8_t l2h_crossing_value, 
+//translate 11111100000 to 10
+size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t maxConsequtiveBits,
+    uint8_t invert, uint8_t fchigh, uint8_t fclow)
 {
-    uint8_t lastval=dest[0];
-    uint32_t idx=0;
-    size_t numBits=0;
-    uint32_t n=1;
+       uint8_t lastval=dest[0];
+       uint32_t idx=0;
+       size_t numBits=0;
+       uint32_t n=1;
 
-    for( idx=1; idx < size; idx++) {
+       for( idx=1; idx < size; idx++) {
 
-        if (dest[idx]==lastval) {
-            n++;
-            continue;
-        }
-        //if lastval was 1, we have a 1->0 crossing
-        if ( dest[idx-1]==1 ) {
-            n=myround2((float)(n+1)/((float)(rfLen)/(float)fclow));
-            //n=(n+1) / h2l_crossing_value;
-        } else {// 0->1 crossing
-            n=myround2((float)(n+1)/((float)(rfLen-2)/(float)fchigh));  //-2 for fudge factor
-            //n=(n+1) / l2h_crossing_value;
-        }
-        if (n == 0) n = 1;
-
-        if(n < maxConsequtiveBits) //Consecutive
-        {
-            if(invert==0){ //invert bits
-                memset(dest+numBits, dest[idx-1] , n);
-            }else{
-                memset(dest+numBits, dest[idx-1]^1 , n);
-            }
-            numBits += n;
-        }
-        n=0;
-        lastval=dest[idx];
-    }//end for
-    return numBits;
+               if (dest[idx]==lastval) {
+                       n++;
+                       continue;
+               }
+               //if lastval was 1, we have a 1->0 crossing
+               if ( dest[idx-1]==1 ) {
+                       n=myround2((float)(n+1)/((float)(rfLen)/(float)fclow));
+               } else {// 0->1 crossing
+                       n=myround2((float)(n+1)/((float)(rfLen-1)/(float)fchigh));  //-1 for fudge factor
+               }
+               if (n == 0) n = 1;
+
+               if(n < maxConsequtiveBits) //Consecutive
+               {
+                       if(invert==0){ //invert bits
+                               memset(dest+numBits, dest[idx-1] , n);
+                       }else{
+                               memset(dest+numBits, dest[idx-1]^1 , n);
+                       }
+                       numBits += n;
+               }
+               n=0;
+               lastval=dest[idx];
+       }//end for
+       return numBits;
 }
 //by marshmellow  (from holiman's base)
 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
 {
-    // FSK demodulator
-    size = fsk_wave_demod(dest, size, fchigh, fclow);
-    size = aggregate_bits(dest, size,rfLen,192,invert,fchigh,fclow);
-    return size;
+       // FSK demodulator
+       size = fsk_wave_demod(dest, size, fchigh, fclow);
+       size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow);
+       return size;
 }
+
 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
-int HIDdemodFSK(uint8_t *dest, size_t size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
+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,
-    // 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_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
     }
-    return -1;
+    *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;
 }
 
-uint32_t bytebits_to_byte(uint8_t* src, int numbits)
+// 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)
 {
-    uint32_t num = 0;
-    for(int i = 0 ; i < numbits ; i++)
-    {
-        num = (num << 1) | (*src);
-        src++;
-    }
-    return num;
+       if (justNoise(dest, *size)) return -1;
+       
+       size_t numStart=0, size2=*size, startIdx=0;
+       // FSK demodulator
+       *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
+       if (*size < 96) return -2;
+
+       // 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 (int)startIdx;
 }
 
-int IOdemodFSK(uint8_t *dest, size_t size)
+uint32_t bytebits_to_byte(uint8_t* src, size_t numbits)
 {
-       static const uint8_t THRESHOLD = 140;
-    uint32_t idx=0;
-    //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;
+       uint32_t num = 0;
+       for(int i = 0 ; i < numbits ; i++)
+       {
+               num = (num << 1) | (*src);
+               src++;
        }
-       if(justNoise) return 0;
+       return num;
+}
 
+int IOdemodFSK(uint8_t *dest, size_t size)
+{
+       if (justNoise(dest, size)) return -1;
+       //make sure buffer has data
+       if (size < 66*64) return -2;
        // FSK demodulator
-       size = fskdemod(dest, size,64,1,10,8);  //  RF/64 and invert
-       if (size < 65) return -1;  //did we get a good demod?
+       size = fskdemod(dest, size, 64, 1, 10, 8);  // FSK2a RF/64 
+       if (size < 65) return -3;  //did we get a good demod?
        //Index map
        //0           10          20          30          40          50          60
        //|           |           |           |           |           |           |
@@ -615,18 +665,83 @@ int IOdemodFSK(uint8_t *dest, size_t size)
        //
        //XSF(version)facility:codeone+codetwo
        //Handle the data
-       uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1};
-       for( idx=0; idx < (size - 65); idx++) {
-               if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
-                       //frame marker found
-                       if (!dest[idx+8] && dest[idx+17]==1 && dest[idx+26]==1 && dest[idx+35]==1 && dest[idx+44]==1 && dest[idx+53]==1){
-                               //confirmed proper separator bits found
-                               //return start position
-                               return (int) idx;
-                       }
+       size_t startIdx = 0;
+       uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+
+       if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
+               //confirmed proper separator bits found
+               //return start position
+               return (int) startIdx;
+       }
+       return -5;
+}
+
+// by marshmellow
+// takes a array of binary values, start position, length of bits per parity (includes parity bit),
+//   Parity Type (1 for odd 0 for even), and binary Length (length to run) 
+size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
+{
+       uint32_t parityWd = 0;
+       size_t j = 0, bitCnt = 0;
+       for (int word = 0; word < (bLen); word+=pLen){
+               for (int bit=0; bit < pLen; bit++){
+                       parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
+      BitStream[j++] = (BitStream[startIdx+word+bit]);
                }
+               j--;
+               // if parity fails then return 0
+               if (parityTest(parityWd, pLen, pType) == 0) return -1;
+               bitCnt+=(pLen-1);
+               parityWd = 0;
        }
-    return 0;
+       // if we got here then all the parities passed
+       //return ID start index and size
+       return bitCnt;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an AWID ID
+int AWIDdemodFSK(uint8_t *dest, size_t *size)
+{
+       //make sure buffer has enough data
+       if (*size < 96*50) return -1;
+
+       if (justNoise(dest, *size)) return -2;
+
+       // FSK demodulator
+       *size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
+       if (*size < 96) return -3;  //did we get a good demod?
+
+       uint8_t preamble[] = {0,0,0,0,0,0,0,1};
+       size_t startIdx = 0;
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       if (*size != 96) return -5;
+       return (int)startIdx;
+}
+
+// by marshmellow
+// FSK Demod then try to locate an Farpointe Data (pyramid) ID
+int PyramiddemodFSK(uint8_t *dest, size_t *size)
+{
+  //make sure buffer has data
+  if (*size < 128*50) return -5;
+
+  //test samples are not just noise
+  if (justNoise(dest, *size)) return -1;
+
+  // FSK demodulator
+  *size = fskdemod(dest, *size, 50, 1, 10, 8);  // fsk2a RF/50 
+  if (*size < 128) return -2;  //did we get a good demod?
+
+  uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
+       size_t startIdx = 0;
+       uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+       if (errChk == 0) return -4; //preamble not found
+       if (*size != 128) return -3;
+       return (int)startIdx;
 }
 
 // by marshmellow
@@ -634,67 +749,582 @@ int IOdemodFSK(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)
 {
-    int i=0;
-    int peak=0;
-    int low=128;
-    int clk[]={16,32,40,50,64,100,128,256};
-    int loopCnt = 256;  //don't need to loop through entire array...
-    if (size<loopCnt) loopCnt = size;
-
-    //if we already have a valid clock quit
-    for (;i<8;++i)
-        if (clk[i]==clock) return clock;
-
-    //get high and low peak
-    for (i=0;i<loopCnt;++i){
-        if(dest[i]>peak){
-            peak = dest[i];
-        }
-        if(dest[i]<low){
-            low = dest[i];
-        }
+  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;
+
+  //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;
     }
-    peak=(int)((peak-128)*.75)+128;
-    low= (int)((low-128)*.75)+128;
-    int ii;
-    int clkCnt;
-    int tol = 0;
-    int bestErr=1000;
-    int errCnt[]={0,0,0,0,0,0,0,0};
-    //test each valid clock from smallest to greatest to see which lines up
-    for(clkCnt=0; clkCnt<6;++clkCnt){
-        if (clk[clkCnt]==32){
-            tol=1;
-        }else{
-            tol=0;
+    bestErr[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++;
+          }
         }
-        bestErr=1000;
-        //try lining up the peaks by moving starting point (try first 256)
-        for (ii=0; ii<loopCnt; ++ii){
-            if ((dest[ii]>=peak) || (dest[ii]<=low)){
-                errCnt[clkCnt]=0;
-                // now that we have the first one lined up test rest of wave array
-                for (i=0; i<((int)(size/clk[clkCnt])-1); ++i){
-                    if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
-                    }else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
-                    }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
-                    }else{  //error no peak detected
-                        errCnt[clkCnt]++;
-                    }
-                }
-                //if we found no errors this is correct one - return this clock
-                if(errCnt[clkCnt]==0) return clk[clkCnt];
-                //if we found errors see if it is lowest so far and save it as best run
-                if(errCnt[clkCnt]<bestErr) bestErr=errCnt[clkCnt];
+        //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
+//detect psk clock by reading #peaks vs no peaks(or errors)
+int DetectpskNRZClock(uint8_t dest[], size_t size, int clock)
+{
+       int i=0;
+       int clk[]={16,32,40,50,64,100,128,256};
+       int loopCnt = 2048;  //don't need to loop through entire array...
+       if (size<loopCnt) loopCnt = size;
+
+       //if we already have a valid clock quit
+       for (; i < 7; ++i)
+               if (clk[i] == clock) return clock;
+
+       //get high and low peak
+       int peak, low;
+       getHiLo(dest, loopCnt, &peak, &low, 75, 75);
+
+       //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
+       int ii;
+       uint8_t clkCnt;
+       uint8_t tol = 0;
+       int peakcnt=0;
+       int errCnt=0;
+       int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000};
+       int peaksdet[]={0,0,0,0,0,0,0,0};
+       //test each valid clock from smallest to greatest to see which lines up
+       for(clkCnt=0; clkCnt < 7; ++clkCnt){
+               if (clk[clkCnt] <= 32){
+                       tol=1;
+               }else{
+                       tol=0;
+               }
+               //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;
+                               peakcnt=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){
+                                               peakcnt++;
+                                       }else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
+                                               peakcnt++;
+                                       }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
+                                               peakcnt++;
+                                       }else{  //error no peak detected
+                                               errCnt++;
+                                       }
+                               }
+                               if(peakcnt>peaksdet[clkCnt]) {
+                                       peaksdet[clkCnt]=peakcnt;
+                                       bestErr[clkCnt]=errCnt;
+                               }
+                       }
+               }
+       }
+       int iii=0;
+       int best=0;
+       //int ratio2;  //debug
+       int ratio;
+       //int bits;
+       for (iii=0; iii < 7; ++iii){
+               ratio=1000;
+               //ratio2=1000;  //debug
+               //bits=size/clk[iii];  //debug
+               if (peaksdet[iii] > 0){
+                       ratio=bestErr[iii]/peaksdet[iii];
+                       if (((bestErr[best]/peaksdet[best]) > (ratio)+1)){
+                               best = iii;
+                       }
+                       //ratio2=bits/peaksdet[iii]; //debug
+               }
+               //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d, ratio: %d, bits: %d, peakbitr: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best],ratio, bits,ratio2);
+       }
+       return clk[best];
+}
+
+// by marshmellow (attempt to get rid of high immediately after a low)
+void pskCleanWave(uint8_t *BitStream, size_t size)
+{
+       int i;
+       int gap = 4;
+       int newLow=0;
+       int newHigh=0;
+       int high, low;
+       getHiLo(BitStream, size, &high, &low, 80, 90);
+       for (i=0; i < size; ++i){
+               if (newLow == 1){
+                       if (BitStream[i]>low){
+                               BitStream[i]=low+8;
+                               gap--;
+                       }
+                       if (gap == 0){
+                               newLow=0;
+                               gap=4;
+                       }
+               }else if (newHigh == 1){
+                       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;
+       }
+       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
+int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
+{
+       //26 bit 40134 format  (don't know other formats)
+       int i;
+       int long_wait=29;//29 leading zeros in format
+       int start;
+       int first = 0;
+       int first2 = 0;
+       int bitCnt = 0;
+       int ii;
+       // Finding the start of a UID
+       for (start = 0; start <= *size - 250; start++) {
+               first = bitStream[start];
+               for (i = start; i < start + long_wait; i++) {
+                       if (bitStream[i] != first) {
+                               break;
+                       }
+               }
+               if (i == (start + long_wait)) {
+                       break;
+               }
+       }
+       if (start == *size - 250 + 1) {
+               // did not find start sequence
+               return -1;
+       }
+       // Inverting signal if needed
+       if (first == 1) {
+               for (i = start; i < *size; i++) {
+                       bitStream[i] = !bitStream[i];
+               }
+               *invert = 1;
+       }else *invert=0;
+
+       int iii;
+       //found start once now test length by finding next one
+       for (ii=start+29; ii <= *size - 250; ii++) {
+               first2 = bitStream[ii];
+               for (iii = ii; iii < ii + long_wait; iii++) {
+                       if (bitStream[iii] != first2) {
+                               break;
+                       }
+               }
+               if (iii == (ii + long_wait)) {
+                       break;
+               }
+       }
+       if (ii== *size - 250 + 1){
+               // did not find second start sequence
+               return -2;
+       }
+       bitCnt=ii-start;
+
+       // Dumping UID
+       i = start;
+       for (ii = 0; ii < bitCnt; ii++) {
+               bitStream[ii] = bitStream[i++];
+       }
+       *size=bitCnt;
+       return 1;
+}
+
+// by marshmellow - demodulate PSK1 wave or NRZ wave (both similar enough)
+// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
+int pskNRZrawDemod(uint8_t *dest, size_t *size, int *clk, int *invert)
+{
+       if (justNoise(dest, *size)) return -1;
+       pskCleanWave(dest,*size);
+       int clk2 = DetectpskNRZClock(dest, *size, *clk);
+       *clk=clk2;
+       uint32_t i;
+       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;
+       //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 = 1;  //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
+       if (*clk==32) tol = 2;    //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
+       uint32_t iii = 0;
+       uint8_t errCnt =0;
+       uint32_t bestStart = *size;
+       uint32_t maxErr = (*size/1000);
+       uint32_t bestErrCnt = maxErr;
+       uint8_t curBit=0;
+       uint8_t bitHigh=0;
+       uint8_t ignorewin=*clk/8;
+       //PrintAndLog("DEBUG - lastbit - %d",lastBit);
+       //loop to find first wave that works - align to clock
+       for (iii=0; iii < gLen; ++iii){
+               if ((dest[iii]>=high) || (dest[iii]<=low)){
+                       lastBit=iii-*clk;
+                       //loop through to see if this start location works
+                       for (i = iii; i < *size; ++i) {
+                               //if we found a high bar and we are at a clock bit
+                               if ((dest[i]>=high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
+                                       bitHigh=1;
+                                       lastBit+=*clk;
+                                       ignorewin=*clk/8;
+                                       bitnum++;
+                               //else if low bar found and we are at a clock point
+                               }else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
+                                       bitHigh=1;
+                                       lastBit+=*clk;
+                                       ignorewin=*clk/8;
+                                       bitnum++;
+                               //else if no bars found
+                               }else if(dest[i] < high && dest[i] > low) {
+                                       if (ignorewin==0){
+                                               bitHigh=0;
+                                       }else ignorewin--;
+                                                                               //if we are past a clock point
+                                       if (i >= lastBit+*clk+tol){ //clock val
+                                               lastBit+=*clk;
+                                               bitnum++;
+                                       }
+                               //else if bar found but we are not at a clock bit and we did not just have a clock bit
+                               }else if ((dest[i]>=high || dest[i]<=low) && (i<lastBit+*clk-tol || i>lastBit+*clk+tol) && (bitHigh==0)){
+                                       //error bar found no clock...
+                                       errCnt++;
+                               }
+                               if (bitnum>=1000) break;
+                       }
+                       //we got more than 64 good bits and not all errors
+                       if ((bitnum > (64+errCnt)) && (errCnt < (maxErr))) {
+                               //possible good read
+                               if (errCnt == 0){
+                                       bestStart = iii;
+                                       bestErrCnt = errCnt;
+                                       break;  //great read - finish
+                               }
+                               if (errCnt < bestErrCnt){  //set this as new best run
+                                       bestErrCnt = errCnt;
+                                       bestStart = iii;
+                               }
+                       }
+               }
+       }
+       if (bestErrCnt < maxErr){
+               //best run is good enough set to best run and set overwrite BinStream
+               iii=bestStart;
+               lastBit=bestStart-*clk;
+               bitnum=0;
+               for (i = iii; i < *size; ++i) {
+                       //if we found a high bar and we are at a clock bit
+                       if ((dest[i] >= high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
+                               bitHigh=1;
+                               lastBit+=*clk;
+                               curBit=1-*invert;
+                               dest[bitnum]=curBit;
+                               ignorewin=*clk/8;
+                               bitnum++;
+                       //else if low bar found and we are at a clock point
+                       }else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
+                               bitHigh=1;
+                               lastBit+=*clk;
+                               curBit=*invert;
+                               dest[bitnum]=curBit;
+                               ignorewin=*clk/8;
+                               bitnum++;
+                       //else if no bars found
+                       }else if(dest[i]<high && dest[i]>low) {
+                               if (ignorewin==0){
+                                       bitHigh=0;
+                               }else ignorewin--;
+                               //if we are past a clock point
+                               if (i>=lastBit+*clk+tol){ //clock val
+                                       lastBit+=*clk;
+                                       dest[bitnum]=curBit;
+                                       bitnum++;
+                               }
+                       //else if bar found but we are not at a clock bit and we did not just have a clock bit
+                       }else if ((dest[i]>=high || dest[i]<=low) && ((i<lastBit+*clk-tol) || (i>lastBit+*clk+tol)) && (bitHigh==0)){
+                               //error bar found no clock...
+                               bitHigh=1;
+                               dest[bitnum]=77;
+                               bitnum++;
+                               errCnt++;
+                       }
+                       if (bitnum >=1000) break;
+               }
+               *size=bitnum;
+       } else{
+               *size=bitnum;
+               *clk=bestStart;
+               return -1;
+       }
+
+       if (bitnum>16){
+               *size=bitnum;
+       } else return -1;
+       return errCnt;
+}
+
+//by marshmellow
+//detects the bit clock for FSK given the high and low Field Clocks
+uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
+{
+  uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
+  uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+  uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+  uint8_t rfLensFnd = 0;
+  uint8_t lastFCcnt=0;
+  uint32_t fcCounter = 0;
+  uint16_t rfCounter = 0;
+  uint8_t firstBitFnd = 0;
+  size_t i;
+
+  uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
+  rfLensFnd=0;
+  fcCounter=0;
+  rfCounter=0;
+  firstBitFnd=0;
+  //PrintAndLog("DEBUG: fcTol: %d",fcTol);
+  // prime i to first up transition
+  for (i = 1; i < size-1; i++)
+    if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
+      break;
+
+  for (; i < size-1; i++){
+    if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]){
+      // new peak 
+      fcCounter++;
+      rfCounter++;
+      // if we got less than the small fc + tolerance then set it to the small fc
+      if (fcCounter < fcLow+fcTol) 
+        fcCounter = fcLow;
+      else //set it to the large fc
+        fcCounter = fcHigh;
+     
+      //look for bit clock  (rf/xx)
+      if ((fcCounter<lastFCcnt || fcCounter>lastFCcnt)){
+        //not the same size as the last wave - start of new bit sequence
+
+        if (firstBitFnd>1){ //skip first wave change - probably not a complete bit
+          for (int ii=0; ii<15; ii++){
+            if (rfLens[ii]==rfCounter){
+              rfCnts[ii]++;
+              rfCounter=0;
+              break;
             }
+          }
+          if (rfCounter>0 && rfLensFnd<15){
+            //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+            rfCnts[rfLensFnd]++;
+            rfLens[rfLensFnd++]=rfCounter;
+          }
+        } else {
+          firstBitFnd++;
         }
+        rfCounter=0;
+        lastFCcnt=fcCounter;
+      }
+      fcCounter=0;
+    } else {
+      // count sample
+      fcCounter++;
+      rfCounter++;
     }
-    int iii=0;
-    int best=0;
-    for (iii=0; iii<6;++iii){
-        if (errCnt[iii]<errCnt[best]){
-            best = iii;
+  }
+  uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
+
+  for (i=0; i<15; i++){
+    //PrintAndLog("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]);
+    //get highest 2 RF values  (might need to get more values to compare or compare all?)
+    if (rfCnts[i]>rfCnts[rfHighest]){
+      rfHighest3=rfHighest2;
+      rfHighest2=rfHighest;
+      rfHighest=i;
+    } else if(rfCnts[i]>rfCnts[rfHighest2]){
+      rfHighest3=rfHighest2;
+      rfHighest2=i;
+    } else if(rfCnts[i]>rfCnts[rfHighest3]){
+      rfHighest3=i;
+    }
+  }  
+  // set allowed clock remainder tolerance to be 1 large field clock length+1 
+  //   we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off  
+  uint8_t tol1 = fcHigh+1; 
+  
+  //PrintAndLog("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
+
+  // loop to find the highest clock that has a remainder less than the tolerance
+  //   compare samples counted divided by
+  int ii=7;
+  for (; ii>=0; ii--){
+    if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
+      if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
+        if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
+          break;
         }
+      }
     }
-    return clk[best];
+  }
+
+  if (ii<0) return 0; // oops we went too far
+
+  return clk[ii];
+}
+
+//by marshmellow
+//countFC is to detect the field clock lengths.
+//counts and returns the 2 most common wave lengths
+uint16_t countFC(uint8_t *BitStream, size_t size)
+{
+  uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0};
+  uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
+  uint8_t fcLensFnd = 0;
+  uint8_t lastFCcnt=0;
+  uint32_t fcCounter = 0;
+  size_t i;
+  
+  // prime i to first up transition
+  for (i = 1; i < size-1; i++)
+    if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
+      break;
+
+  for (; i < size-1; i++){
+    if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
+       // new up transition
+       fcCounter++;
+       
+      //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
+      if (lastFCcnt==5 && fcCounter==9) fcCounter--;
+      //if odd and not rc/5 add one (for when we get a fc 9 instead of 10)
+      if ((fcCounter==9 && fcCounter & 1) || fcCounter==4) fcCounter++;
+
+      // save last field clock count  (fc/xx)
+      // find which fcLens to save it to:
+      for (int ii=0; ii<10; ii++){
+        if (fcLens[ii]==fcCounter){
+          fcCnts[ii]++;
+          fcCounter=0;
+          break;
+        }
+      }
+      if (fcCounter>0 && fcLensFnd<10){
+        //add new fc length 
+        fcCnts[fcLensFnd]++;
+        fcLens[fcLensFnd++]=fcCounter;
+      }
+      fcCounter=0;
+    } else {
+      // count sample
+      fcCounter++;
+    }
+  }
+  
+  uint8_t best1=9, best2=9, best3=9;
+  uint16_t maxCnt1=0;
+  // go through fclens and find which ones are bigest 2  
+  for (i=0; i<10; i++){
+    // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d",fcLens[i],fcCnts[i],errCnt);    
+    // get the 3 best FC values
+    if (fcCnts[i]>maxCnt1) {
+      best3=best2;
+      best2=best1;
+      maxCnt1=fcCnts[i];
+      best1=i;
+    } else if(fcCnts[i]>fcCnts[best2]){
+      best3=best2;
+      best2=i;
+    } else if(fcCnts[i]>fcCnts[best3]){
+      best3=i;
+    }
+  }
+  uint8_t fcH=0, fcL=0;
+  if (fcLens[best1]>fcLens[best2]){
+    fcH=fcLens[best1];
+    fcL=fcLens[best2];
+  } else{
+    fcH=fcLens[best2];
+    fcL=fcLens[best1];
+  }
+  // TODO: take top 3 answers and compare to known Field clocks to get top 2
+
+  uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
+  // PrintAndLog("DEBUG: Best %d  best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]);
+  
+  return fcs;
 }
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