RfidResearchGroup/proxmark3
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minor askrawdemod adjustment if errors in demoding are found

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if it can't find a demod position with no errors it will find the one
with fewest errors and mark errors with 77.
This commit is contained in:
marshmellow42 2014-12-23 15:16:53 -05:00
parent 2fc2150ea8
commit cd48c19c31
1 changed files with 27 additions and 16 deletions
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43
client/cmddata.c
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@ -302,13 +302,14 @@ int Cmdaskrawdemod(const char *Cmd)
//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 = clk; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
//clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
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 = GraphTraceLen;
if (gLen > 500) gLen=500;
uint8_t errCnt =0;
uint32_t bestStart = GraphTraceLen;
uint32_t bestErrCnt = (GraphTraceLen/1000);
//PrintAndLog("DEBUG - lastbit - %d",lastBit);
//loop to find first wave that works
@ -317,32 +318,32 @@ int Cmdaskrawdemod(const char *Cmd)
lastBit=iii-clk;
//loop through to see if this start location works
for (i = iii; i < GraphTraceLen; ++i) {
if ((GraphBuffer[i] >= high) && ((i-lastBit)>(clk-((int)clk/tol)))) { // && GraphBuffer[i-1] < high
if ((GraphBuffer[i] >= high) && ((i-lastBit)>(clk-tol))){
lastBit+=clk;
BitStream[bitnum] = invert;
bitnum++;
} else if ((GraphBuffer[i] <= low) && ((i-lastBit)>(clk-((int)clk/tol)))){
} else if ((GraphBuffer[i] <= low) && ((i-lastBit)>(clk-tol))){
//low found and we are expecting a bar
lastBit+=clk;
BitStream[bitnum] = 1-invert;
bitnum++;
} else {
//mid value found or no bar supposed to be here
if ((i-lastBit)>(clk+((int)(clk/tol)))){
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)(clk/tol)))),(lastBit+(clk+((int)(clk/tol)))),lastBit);
//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>((GraphTraceLen/1000)*2)){ //allow 2 errors for every 1000 samples else start over
if (errCnt>((GraphTraceLen/1000))){ //allow 1 error for every 1000 samples else start over
errCnt=0;
bitnum=0;//start over
break;
@ -350,11 +351,21 @@ int Cmdaskrawdemod(const char *Cmd)
}
}
}
//debug
if ((bitnum>64) && (BitStream[bitnum-1]!=77)) break;
}
//we got more than 64 good bits and not all errors
if ((bitnum > (64+errCnt)) && (errCnt<(GraphTraceLen/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 < (GraphTraceLen/1000)) iii=bestStart;
}
}
if (bitnum>16){
PrintAndLog("Data start pos:%d, lastBit:%d, stop pos:%d, numBits:%d",iii,lastBit,i,bitnum);
@ -367,7 +378,7 @@ int Cmdaskrawdemod(const char *Cmd)
RepaintGraphWindow();
//output
if (errCnt>0){
PrintAndLog("# Errors during Demoding: %d",errCnt);
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