//by marshmellow
-//countFC is to detect the field clock and bit clock rates.
-//for fsk or ask not psk or nrz
-uint32_t countFC(uint8_t *BitStream, size_t size)
+//detects the bit clock for FSK given the high and low Field Clocks
+uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
{
- // get high/low thresholds
- int high, low;
- getHiLo(BitStream,10, &high, &low, 100, 100);
- // get zero crossing
- uint8_t zeroC = (high-low)/2+low;
- uint8_t clk[]={8,16,32,40,50,64,100,128};
- uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0};
- uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
- uint8_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0};
- // uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0};
- uint8_t fcLensFnd = 0;
+ uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
+ uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+ uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint8_t rfLensFnd = 0;
- uint8_t lastBit=0;
- uint8_t curBit=0;
uint8_t lastFCcnt=0;
- uint32_t errCnt=0;
uint32_t fcCounter = 0;
- uint32_t rfCounter = 0;
+ uint16_t rfCounter = 0;
uint8_t firstBitFnd = 0;
- int i;
-
+ size_t i;
+
+ uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
+ rfLensFnd=0;
+ fcCounter=0;
+ rfCounter=0;
+ firstBitFnd=0;
+ //PrintAndLog("DEBUG: fcTol: %d",fcTol);
// prime i to first up transition
- for (i = 1; i < size; i++)
- if (BitStream[i]>=zeroC && BitStream[i-1]<zeroC)
+ for (i = 1; i < size-1; i++)
+ if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
break;
- for (; i < size; i++){
- curBit = BitStream[i];
- lastBit = BitStream[i-1];
- if (lastBit<zeroC && curBit >= zeroC){
- // new up transition
+ for (; i < size-1; i++){
+ if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]){
+ // new peak
fcCounter++;
rfCounter++;
- if (fcCounter > 3 && fcCounter < 256){
- //we've counted enough that it could be a valid field clock
-
- //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
- if (lastFCcnt==5 && fcCounter==9) fcCounter--;
- //if odd and not rc/5 add one (for when we get a fc 9 instead of 10)
- if ((fcCounter==9 && fcCounter & 1) || fcCounter==4) fcCounter++;
+ // if we got less than the small fc + tolerance then set it to the small fc
+ if (fcCounter < fcLow+fcTol)
+ fcCounter = fcLow;
+ else //set it to the large fc
+ fcCounter = fcHigh;
- //look for bit clock (rf/xx)
- if ((fcCounter<lastFCcnt || fcCounter>lastFCcnt)){
- //not the same size as the last wave - start of new bit sequence
-
- if (firstBitFnd>1){ //skip first wave change - probably not a complete bit
- for (int ii=0; ii<10; ii++){
- if (rfLens[ii]==rfCounter){
- //rfCnts[ii]++;
- rfCounter=0;
- break;
- }
+ //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<10){
- //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
- //rfCnts[rfLensFnd]++;
- rfLens[rfLensFnd++]=rfCounter;
- }
- } else {
- //PrintAndLog("DEBUG i: %d",i);
- firstBitFnd++;
}
- rfCounter=0;
- lastFCcnt=fcCounter;
- }
-
- // save last field clock count (fc/xx)
- // find which fcLens to save it to:
- for (int ii=0; ii<10; ii++){
- if (fcLens[ii]==fcCounter){
- fcCnts[ii]++;
- fcCounter=0;
- break;
+ if (rfCounter>0 && rfLensFnd<15){
+ //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
+ rfCnts[rfLensFnd]++;
+ rfLens[rfLensFnd++]=rfCounter;
}
+ } else {
+ firstBitFnd++;
}
- if (fcCounter>0 && fcLensFnd<10){
- //add new fc length
- //PrintAndLog("FCCntr %d",fcCounter);
- fcCnts[fcLensFnd]++;
- fcLens[fcLensFnd++]=fcCounter;
- }
- } else{
- // hmmm this should not happen often - count them
- errCnt++;
+ rfCounter=0;
+ lastFCcnt=fcCounter;
}
- // reset counter
fcCounter=0;
} else {
// count sample
rfCounter++;
}
}
- // if too many errors return errors as negative number (IS THIS NEEDED?)
- if (errCnt>100) return -1*errCnt;
-
- uint8_t maxCnt1=0, best1=9, best2=9, best3=9, rfHighest=10, rfHighest2=10, rfHighest3=10;
+ uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
- // go through fclens and find which ones are bigest 2
- for (i=0; i<10; i++){
- // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d, RF %d",fcLens[i],fcCnts[i],errCnt,rfLens[i]);
-
- // get the 3 best FC values
- if (fcCnts[i]>maxCnt1) {
- best3=best2;
- best2=best1;
- maxCnt1=fcCnts[i];
- best1=i;
- } else if(fcCnts[i]>fcCnts[best2]){
- best3=best2;
- best2=i;
- } else if(fcCnts[i]>fcCnts[best3]){
- best3=i;
- }
+ for (i=0; i<15; i++){
+ //PrintAndLog("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]);
//get highest 2 RF values (might need to get more values to compare or compare all?)
- if (rfLens[i]>rfLens[rfHighest]){
+ if (rfCnts[i]>rfCnts[rfHighest]){
rfHighest3=rfHighest2;
rfHighest2=rfHighest;
rfHighest=i;
- } else if(rfLens[i]>rfLens[rfHighest2]){
+ } else if(rfCnts[i]>rfCnts[rfHighest2]){
rfHighest3=rfHighest2;
rfHighest2=i;
- } else if(rfLens[i]>rfLens[rfHighest3]){
+ } else if(rfCnts[i]>rfCnts[rfHighest3]){
rfHighest3=i;
}
- }
-
- // set allowed clock remainder tolerance to be 1 large field clock length
- // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
- int tol1 = (fcLens[best1]>fcLens[best2]) ? fcLens[best1] : fcLens[best2];
+ }
+ // set allowed clock remainder tolerance to be 1 large field clock length+1
+ // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
+ uint8_t tol1 = fcHigh+1;
+ //PrintAndLog("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
+
// loop to find the highest clock that has a remainder less than the tolerance
- // compare samples counted divided by
+ // compare samples counted divided by
int ii=7;
for (; ii>=0; ii--){
if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
}
}
- if (ii<0) ii=7; // oops we went too far
+ if (ii<0) return 0; // oops we went too far
- // TODO: take top 3 answers and compare to known Field clocks to get top 2
+ return clk[ii];
+}
- uint32_t fcs=0;
- // PrintAndLog("DEBUG: Best %d best2 %d best3 %d, clk %d, clk2 %d",fcLens[best1],fcLens[best2],fcLens[best3],clk[i],clk[ii]);
- //
+//by marshmellow
+//countFC is to detect the field clock lengths.
+//counts and returns the 2 most common wave lengths
+uint16_t countFC(uint8_t *BitStream, size_t size)
+{
+ uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0};
+ uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
+ uint8_t fcLensFnd = 0;
+ uint8_t lastFCcnt=0;
+ uint32_t fcCounter = 0;
+ size_t i;
+
+ // prime i to first up transition
+ for (i = 1; i < size-1; i++)
+ if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
+ break;
+ for (; i < size-1; i++){
+ if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
+ // new up transition
+ fcCounter++;
+
+ //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
+ if (lastFCcnt==5 && fcCounter==9) fcCounter--;
+ //if odd and not rc/5 add one (for when we get a fc 9 instead of 10)
+ if ((fcCounter==9 && fcCounter & 1) || fcCounter==4) fcCounter++;
+
+ // save last field clock count (fc/xx)
+ // find which fcLens to save it to:
+ for (int ii=0; ii<10; ii++){
+ if (fcLens[ii]==fcCounter){
+ fcCnts[ii]++;
+ fcCounter=0;
+ break;
+ }
+ }
+ if (fcCounter>0 && fcLensFnd<10){
+ //add new fc length
+ fcCnts[fcLensFnd]++;
+ fcLens[fcLensFnd++]=fcCounter;
+ }
+ fcCounter=0;
+ } else {
+ // count sample
+ fcCounter++;
+ }
+ }
+
+ uint8_t best1=9, best2=9, best3=9;
+ uint16_t maxCnt1=0;
+ // go through fclens and find which ones are bigest 2
+ for (i=0; i<10; i++){
+ // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d",fcLens[i],fcCnts[i],errCnt);
+ // get the 3 best FC values
+ if (fcCnts[i]>maxCnt1) {
+ best3=best2;
+ best2=best1;
+ maxCnt1=fcCnts[i];
+ best1=i;
+ } else if(fcCnts[i]>fcCnts[best2]){
+ best3=best2;
+ best2=i;
+ } else if(fcCnts[i]>fcCnts[best3]){
+ best3=i;
+ }
+ }
+ uint8_t fcH=0, fcL=0;
if (fcLens[best1]>fcLens[best2]){
- fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best1])<<8) | ((fcLens[best2]));
- } else {
- fcs = (((uint32_t)clk[ii])<<16) | (((uint32_t)fcLens[best2])<<8) | ((fcLens[best1]));
+ fcH=fcLens[best1];
+ fcL=fcLens[best2];
+ } else{
+ fcH=fcLens[best2];
+ fcL=fcLens[best1];
}
+
+ // TODO: take top 3 answers and compare to known Field clocks to get top 2
+ uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
+ // PrintAndLog("DEBUG: Best %d best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]);
+
return fcs;
}
projects / proxmark3-svn / blobdiff