]> git.zerfleddert.de Git - proxmark3-svn/blobdiff - common/lfdemod.c
Merge remote-tracking branch 'upstream/master'
[proxmark3-svn] / common / lfdemod.c
index d3c2a01c96cc8d9c96bf9a5629487db4d5f0322b..c00222b3b69ca23a277f041a027c14a02d2e0feb 100644 (file)
@@ -34,8 +34,8 @@ int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi
                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);
+       *high = ((*high-128)*fuzzHi + 12800)/100;
+       *low = ((*low-128)*fuzzLo + 12800)/100;
        return 1;
 }
 
@@ -114,6 +114,57 @@ uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_
        return 0;
 }
 
+// demodulates strong heavily clipped samples
+int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
+{
+       size_t bitCnt=0, smplCnt=0, errCnt=0;
+       uint8_t waveHigh = 0;
+       //PrintAndLog("clk: %d", clk);
+       for (size_t i=0; i < *size; i++){
+               if (BinStream[i] >= high && waveHigh){
+                       smplCnt++;
+               } else if (BinStream[i] <= low && !waveHigh){
+                       smplCnt++;
+               } else { //transition
+                       if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
+                               if (smplCnt > clk-(clk/4)-1) { //full clock
+                                       if (smplCnt > clk + (clk/4)+1) { //too many samples
+                                               errCnt++;
+                                               BinStream[bitCnt++]=77;
+                                       } else if (waveHigh) {
+                                               BinStream[bitCnt++] = invert;
+                                               BinStream[bitCnt++] = invert;
+                                       } else if (!waveHigh) {
+                                               BinStream[bitCnt++] = invert ^ 1;
+                                               BinStream[bitCnt++] = invert ^ 1;
+                                       }
+                                       waveHigh ^= 1;  
+                                       smplCnt = 0;
+                               } else if (smplCnt > (clk/2) - (clk/4)-1) {
+                                       if (waveHigh) {
+                                               BinStream[bitCnt++] = invert;
+                                       } else if (!waveHigh) {
+                                               BinStream[bitCnt++] = invert ^ 1;
+                                       }
+                                       waveHigh ^= 1;  
+                                       smplCnt = 0;
+                               } else if (!bitCnt) {
+                                       //first bit
+                                       waveHigh = (BinStream[i] >= high);
+                                       smplCnt = 1;
+                               } else {
+                                       smplCnt++;
+                                       //transition bit oops
+                               }
+                       } else { //haven't hit new high or new low yet
+                               smplCnt++;
+                       }
+               }
+       }
+       *size = bitCnt;
+       return errCnt;
+}
+
 //by marshmellow
 //takes 3 arguments - clock, invert, maxErr as integers
 //attempts to demodulate ask while decoding manchester
@@ -121,7 +172,7 @@ uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_
 int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr)
 {
        size_t i;
-       int start = DetectASKClock(BinStream, *size, clk, 20); //clock default
+       int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
        if (*clk==0 || start < 0) return -3;
        if (*invert != 1) *invert=0;
        uint8_t initLoopMax = 255;
@@ -131,58 +182,20 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
        int high, low;
        if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) return -2; //just noise
 
+       // if clean clipped waves detected run alternate demod
+       if (DetectCleanAskWave(BinStream, *size, high, low)) {
+               cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
+               return manrawdecode(BinStream, size);   
+       }
+
        // PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
-       int lastBit = 0;  //set first clock check
+       int lastBit;  //set first clock check
        uint16_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
-       size_t iii = 0;
-       //if 0 errors allowed then only try first 2 clock cycles as we want a low tolerance
-       if (!maxErr) initLoopMax = *clk * 2; 
        uint16_t errCnt = 0, MaxBits = 512;
-       uint16_t bestStart = start;
-       uint16_t bestErrCnt = 0;
-       // PrintAndLog("DEBUG - lastbit - %d",lastBit);
-       // if best start position not already found by detect clock then
-       if (start <= 0 || start > initLoopMax){
-               bestErrCnt = maxErr+1;
-               // loop to find first wave that works
-               for (iii=0; iii < initLoopMax; ++iii){
-                       // if no peak skip
-                       if (BinStream[iii] < high && BinStream[iii] > low) continue;
-
-                       lastBit = iii - *clk;
-                       // loop through to see if this start location works
-                       for (i = iii; i < *size; ++i) {
-                               if ((i-lastBit) > (*clk-tol) && (BinStream[i] >= high || BinStream[i] <= low)) {
-                                               lastBit += *clk;
-                               } else if ((i-lastBit) > (*clk+tol)) {
-                                       errCnt++;
-                                       lastBit += *clk;
-                               }
-                               if ((i-iii) > (MaxBits * *clk) || errCnt > maxErr) break; //got plenty of bits or too many errors
-                       }
-                       //we got more than 64 good bits and not all errors
-                       if ((((i-iii)/ *clk) > (64)) && (errCnt<=maxErr)) {
-                               //possible good read
-                               if (!errCnt || errCnt < bestErrCnt){
-                                       bestStart = iii; //set this as new best run
-                                       bestErrCnt = errCnt;
-                                       if (!errCnt) break;  //great read - finish
-                               }
-                       }
-                       errCnt = 0;
-               }
-       }
-       if (bestErrCnt > maxErr){
-               *invert = bestStart;
-               *clk = iii;
-               return -1;
-       }               
-       //best run is good enough set to best run and set overwrite BinStream
-       lastBit = bestStart - *clk;
-       errCnt = 0;
-       for (i = bestStart; i < *size; ++i) {
+       lastBit = start - *clk;
+       for (i = start; i < *size; ++i) {
                if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
                        //high found and we are expecting a bar
                        lastBit += *clk;
@@ -203,7 +216,7 @@ int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
                if (bitnum >= MaxBits) break;
        }
        *size = bitnum;
-       return bestErrCnt;
+       return errCnt;
 }
 
 //by marshmellow
@@ -242,19 +255,17 @@ int manrawdecode(uint8_t * BitStream, size_t *size)
                }
                errCnt=0;
        }
-       if (bestErr<20){
-               for (i=bestRun; 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;
-                       }
-                       if(bitnum>MaxBits) break;
+       for (i=bestRun; 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;
                }
-               *size=bitnum;
+               if(bitnum>MaxBits) break;
        }
+       *size=bitnum;
        return bestErr;
 }
 
@@ -319,70 +330,19 @@ void askAmp(uint8_t *BitStream, size_t size)
        return;
 }
 
-// demodulates strong heavily clipped samples
-int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
-{
-       size_t bitCnt=0, smplCnt=0, errCnt=0;
-       uint8_t waveHigh = 0;
-       //PrintAndLog("clk: %d", clk);
-       for (size_t i=0; i < *size; i++){
-               if (BinStream[i] >= high && waveHigh){
-                       smplCnt++;
-               } else if (BinStream[i] <= low && !waveHigh){
-                       smplCnt++;
-               } else { //transition
-                       if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
-                               if (smplCnt > clk-(clk/4)-1) { //full clock
-                                       if (smplCnt > clk + (clk/4)+1) { //too many samples
-                                               errCnt++;
-                                               BinStream[bitCnt++]=77;
-                                       } else if (waveHigh) {
-                                               BinStream[bitCnt++] = invert;
-                                               BinStream[bitCnt++] = invert;
-                                       } else if (!waveHigh) {
-                                               BinStream[bitCnt++] = invert ^ 1;
-                                               BinStream[bitCnt++] = invert ^ 1;
-                                       }
-                                       waveHigh ^= 1;  
-                                       smplCnt = 0;
-                               } else if (smplCnt > (clk/2) - (clk/4)-1) {
-                                       if (waveHigh) {
-                                               BinStream[bitCnt++] = invert;
-                                       } else if (!waveHigh) {
-                                               BinStream[bitCnt++] = invert ^ 1;
-                                       }
-                                       waveHigh ^= 1;  
-                                       smplCnt = 0;
-                               } else if (!bitCnt) {
-                                       //first bit
-                                       waveHigh = (BinStream[i] >= high);
-                                       smplCnt = 1;
-                               } else {
-                                       smplCnt++;
-                                       //transition bit oops
-                               }
-                       } else { //haven't hit new high or new low yet
-                               smplCnt++;
-                       }
-               }
-       }
-       *size = bitCnt;
-       return errCnt;
-}
-
 //by marshmellow
 //takes 3 arguments - clock, invert and maxErr as integers
 //attempts to demodulate ask only
 int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp)
 {
        if (*size==0) return -1;
-       int start = DetectASKClock(BinStream, *size, clk, 20); //clock default
+       int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
        if (*clk==0 || start < 0) return -1;
        if (*invert != 1) *invert = 0;
        if (amp==1) askAmp(BinStream, *size);
 
        uint8_t initLoopMax = 255;
-       if (initLoopMax > *size) initLoopMax=*size;
+       if (initLoopMax > *size) initLoopMax = *size;
        // Detect high and lows
        //25% clip in case highs and lows aren't clipped [marshmellow]
        int high, low;
@@ -393,67 +353,13 @@ int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int max
        if (DetectCleanAskWave(BinStream, *size, high, low))
                return cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
 
-       int lastBit = 0;  //set first clock check - can go negative
-       size_t i, iii = 0;
-       size_t errCnt = 0, bitnum = 0;     //output counter
+       int lastBit;  //set first clock check - can go negative
+       size_t i, errCnt = 0, bitnum = 0;     //output counter
        uint8_t midBit = 0;
-       size_t bestStart = start, bestErrCnt = 0; //(*size/1000);
        size_t MaxBits = 1024;
+       lastBit = start - *clk;
 
-       //if 0 errors allowed then only try first 2 clock cycles as we want a low tolerance
-       if (!maxErr) initLoopMax = *clk * 2; 
-       //if best start not already found by detectclock
-       if (start <= 0 || start > initLoopMax){
-               bestErrCnt = maxErr+1;
-               //PrintAndLog("DEBUG - lastbit - %d",lastBit);
-               //loop to find first wave that works
-               for (iii=0; iii < initLoopMax; ++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 (i-lastBit > *clk && (BinStream[i] >= high || BinStream[i] <= low)){
-                                               lastBit += *clk;
-                                               midBit = 0;
-                                       } else if (i-lastBit > (*clk/2) && midBit == 0) {
-                                               midBit = 1;
-                                       } else if ((i-lastBit) > *clk) {
-                                               //should have hit a high or low based on clock!!
-                                               //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
-                                               errCnt++;
-                                               lastBit += *clk;//skip over until hit too many errors
-                                               if (errCnt > maxErr) 
-                                                       break;
-                                       }
-                                       if ((i-iii)>(MaxBits * *clk)) break; //got enough bits
-                               }
-                               //we got more than 64 good bits and not all errors
-                               if ((((i-iii)/ *clk) > 64) && (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;
-                                       }
-                               }
-                               errCnt=0;
-                       }
-               }
-       }
-       if (bestErrCnt > maxErr){
-               *invert = bestStart;
-               *clk = iii;
-               return -1;
-       }
-       //best run is good enough - set to best run and overwrite BinStream
-       lastBit = bestStart - *clk - 1;
-       errCnt = 0;
-
-       for (i = bestStart; i < *size; ++i) {
+       for (i = start; i < *size; ++i) {
                if (i - lastBit > *clk){
                        if (BinStream[i] >= high) {
                                BinStream[bitnum++] = *invert;
@@ -559,28 +465,26 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
        size_t idx=0;
        size_t numBits=0;
        uint32_t n=1;
-       uint16_t lowWaves = ((rfLen*100/fclow));  // (((float)(rfLen))/((float)fclow));
-       uint16_t highWaves = ((rfLen*100/fchigh)); // (((float)(rfLen))/((float)fchigh));
        for( idx=1; idx < size; idx++) {
                n++;
                if (dest[idx]==lastval) continue; 
                
                //if lastval was 1, we have a 1->0 crossing
                if (dest[idx-1]==1) {
-                       if (!numBits && n < lowWaves/100) {
+                       if (!numBits && n < rfLen/fclow) {
                                n=0;
                                lastval = dest[idx];
                                continue;
                        }
-                       n = (size_t)((((n*1000)/lowWaves)+5)/10);
+                       n = (n * fclow + rfLen/2) / rfLen;
                } else {// 0->1 crossing 
                        //test first bitsample too small
-                       if (!numBits && n < highWaves/100) {
+                       if (!numBits && n < rfLen/fchigh) {
                                n=0;
                                lastval = dest[idx];
                                continue;
                        }
-                       n = (((n*1000)/highWaves)+5)/10
+                       n = (n * fchigh + rfLen/2) / rfLen
                }
                if (n == 0) n = 1;
 
@@ -590,11 +494,11 @@ size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
                lastval=dest[idx];
        }//end for
        // if valid extra bits at the end were all the same frequency - add them in
-       if (n > highWaves/100) {
+       if (n > rfLen/fchigh) {
                if (dest[idx-2]==1) {
-                       n=(((n*1000)/lowWaves)+5)/10;
+                       n = (n * fclow + rfLen/2) / rfLen;
                } else {
-                       n=(((n*1000)/highWaves)+5)/10;
+                       n = (n * fchigh + rfLen/2) / rfLen;
                }
                memset(dest+numBits, dest[idx-1]^invert , n);
                numBits += n;
@@ -858,14 +762,17 @@ int DetectStrongAskClock(uint8_t dest[], size_t size)
 // return start index of best starting position for that clock and return clock (by reference)
 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
 {
-       size_t i=0;
-       uint8_t clk[]={8,16,32,40,50,64,100,128,255};
+       size_t i=1;
+       uint8_t clk[]={255,8,16,32,40,50,64,100,128,255};
        uint8_t loopCnt = 255;  //don't need to loop through entire array...
-       if (size <= loopCnt) return -1; //not enough samples
-       //if we already have a valid clock quit
-       
-       for (;i<8;++i)
-               if (clk[i] == *clock) return 0;
+       if (size==0) return -1;
+       if (size <= loopCnt) loopCnt = size-1; //not enough samples
+
+       //if we already have a valid clock
+       uint8_t clockFnd=0;
+       for (;i<9;++i)
+               if (clk[i] == *clock) clockFnd=i;
+               //clock found but continue to find best startpos
 
        //get high and low peak
        int peak, low;
@@ -874,10 +781,11 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
        //test for large clean peaks
        if (DetectCleanAskWave(dest, size, peak, low)==1){
                int ans = DetectStrongAskClock(dest, size);
-               for (i=7; i>0; i--){
+               for (i=8; i>1; i--){
                        if (clk[i] == ans) {
                                *clock = ans;
-                               return 0;
+                               clockFnd = i;
+                               break; //clock found but continue to find best startpos
                        }
                }
        }
@@ -888,16 +796,20 @@ int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
        size_t errCnt = 0;
        size_t arrLoc, loopEnd;
        //test each valid clock from smallest to greatest to see which lines up
-       for(clkCnt=0; clkCnt < 8; clkCnt++){
+       uint8_t clkEnd=9;
+       if (clockFnd>0) clkEnd=clockFnd+1;
+       else clockFnd=1;
+
+       for(clkCnt=clockFnd; clkCnt < clkEnd; clkCnt++){
                if (clk[clkCnt] == 32){
                        tol=1;
                }else{
                        tol=0;
                }
-               if (!maxErr) loopCnt=clk[clkCnt]*2;
+               if (!maxErr && loopCnt>clk[clkCnt]*3) loopCnt=clk[clkCnt]*3;
                bestErr[clkCnt]=1000;
-               //try lining up the peaks by moving starting point (try first 256)
-               for (ii=0; ii < loopCnt; ii++){
+               //try lining up the peaks by moving starting point (try first few clocks)
+               for (ii=0; ii < loopCnt-tol-clk[clkCnt]; ii++){
                        if (dest[ii] < peak && dest[ii] > low) continue;
 
                        errCnt=0;
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