+// by marshmellow
+// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
+// maybe somehow adjust peak trimming value based on samples to fix?
+int DetectClock(int peak)
+ {
+ int i=0;
+ int low=0;
+ int clk[]={16,32,40,50,64,100,128,256};
+ if (!peak){
+ for (i=0;i<GraphTraceLen;++i){
+ if(GraphBuffer[i]>peak){
+ peak = GraphBuffer[i];
+ }
+ if(GraphBuffer[i]<low){
+ low = GraphBuffer[i];
+ }
+ }
+ peak=(int)(peak*.75);
+ low= (int)(low*.75);
+ }
+ //int numbits;
+ int ii;
+ int loopCnt = 256;
+ if (GraphTraceLen<loopCnt) loopCnt = GraphTraceLen;
+ int clkCnt;
+ int tol = 0;
+ int bestErr=1000;
+ int errCnt[]={0,0,0,0,0,0,0,0};
+ // int good;
+ for(clkCnt=0; clkCnt<6;++clkCnt){
+ if (clk[clkCnt]==32){
+ tol=1;
+ }else{
+ tol=0;
+ }
+ bestErr=1000;
+ for (ii=0; ii<loopCnt; ++ii){
+ if ((GraphBuffer[ii]>=peak) || (GraphBuffer[ii]<=low)){
+ //numbits=0;
+ //good=1;
+ errCnt[clkCnt]=0;
+ for (i=0; i<((int)(GraphTraceLen/clk[clkCnt])-1); ++i){
+ if (GraphBuffer[ii+(i*clk[clkCnt])]>=peak || GraphBuffer[ii+(i*clk[clkCnt])]<=low){
+ //numbits++;
+ }else if(GraphBuffer[ii+(i*clk[clkCnt])-tol]>=peak || GraphBuffer[ii+(i*clk[clkCnt])-tol]<=low){
+ }else if(GraphBuffer[ii+(i*clk[clkCnt])+tol]>=peak || GraphBuffer[ii+(i*clk[clkCnt])+tol]<=low){
+ }else{ //error no peak detected
+ //numbits=0;
+ //good=0;
+ errCnt[clkCnt]++;
+ //break;
+ }
+ }
+ if(errCnt[clkCnt]==0) return clk[clkCnt];
+ if(errCnt[clkCnt]<bestErr) bestErr=errCnt[clkCnt];
+ }
+ }
+ errCnt[clkCnt]=bestErr;
+ }
+ int iii=0;
+ int best=0;
+ for (iii=0; iii<6;++iii){
+ if (errCnt[iii]<errCnt[best]){
+ best = iii;
+ }
+ }
+ PrintAndLog("clkCnt: %d, ii: %d, i: %d peak: %d, low: %d, errcnt: %d, errCnt64: %d",clkCnt,ii,i,peak,low,errCnt[best],errCnt[4]);
+ return clk[best];