mirror of
https://github.com/RfidResearchGroup/proxmark3.git
synced 2024-09-20 23:36:31 +08:00
702 lines
26 KiB
C
702 lines
26 KiB
C
//-----------------------------------------------------------------------------
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// Copyright (C) 2014
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//
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// This code is licensed to you under the terms of the GNU GPL, version 2 or,
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// at your option, any later version. See the LICENSE.txt file for the text of
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// the license.
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//-----------------------------------------------------------------------------
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// Low frequency commands
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//-----------------------------------------------------------------------------
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#include <stdlib.h>
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#include <string.h>
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#include "lfdemod.h"
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//by marshmellow
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//takes 1s and 0s and searches for EM410x format - output EM ID
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uint64_t Em410xDecode(uint8_t *BitStream,uint32_t BitLen)
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{
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//no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
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// otherwise could be a void with no arguments
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//set defaults
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int high=0, low=128;
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uint64_t lo=0; //hi=0,
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uint32_t i = 0;
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uint32_t initLoopMax = 65;
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if (initLoopMax>BitLen) initLoopMax=BitLen;
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for (;i < initLoopMax; ++i) //65 samples should be plenty to find high and low values
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{
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if (BitStream[i] > high)
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high = BitStream[i];
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else if (BitStream[i] < low)
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low = BitStream[i];
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}
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if (((high !=1)||(low !=0))){ //allow only 1s and 0s
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// PrintAndLog("no data found");
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return 0;
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}
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uint8_t parityTest=0;
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// 111111111 bit pattern represent start of frame
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uint8_t frame_marker_mask[] = {1,1,1,1,1,1,1,1,1};
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uint32_t idx = 0;
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uint32_t ii=0;
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uint8_t resetCnt = 0;
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while( (idx + 64) < BitLen) {
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restart:
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// search for a start of frame marker
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if ( memcmp(BitStream+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
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{ // frame marker found
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idx+=9;//sizeof(frame_marker_mask);
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for (i=0; i<10;i++){
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for(ii=0; ii<5; ++ii){
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parityTest += BitStream[(i*5)+ii+idx];
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}
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if (parityTest== ((parityTest>>1)<<1)){
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parityTest=0;
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for (ii=0; ii<4;++ii){
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//hi = (hi<<1)|(lo>>31);
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lo=(lo<<1LL)|(BitStream[(i*5)+ii+idx]);
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}
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//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);
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}else {//parity failed
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//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]);
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parityTest=0;
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idx-=8;
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if (resetCnt>5)return 0;
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resetCnt++;
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goto restart;//continue;
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}
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}
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//skip last 5 bit parity test for simplicity.
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return lo;
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}else{
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idx++;
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}
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}
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return 0;
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}
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//by marshmellow
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//takes 2 arguments - clock and invert both as integers
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//attempts to demodulate ask while decoding manchester
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//prints binary found and saves in graphbuffer for further commands
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int askmandemod(uint8_t * BinStream,uint32_t *BitLen,int *clk, int *invert)
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{
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int i;
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int high = 0, low = 128;
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*clk=DetectASKClock(BinStream,(size_t)*BitLen,*clk); //clock default
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if (*clk<8) *clk =64;
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if (*clk<32) *clk=32;
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if (*invert != 0 && *invert != 1) *invert=0;
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uint32_t initLoopMax = 200;
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if (initLoopMax>*BitLen) initLoopMax=*BitLen;
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// Detect high and lows
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for (i = 0; i < initLoopMax; ++i) //200 samples should be enough to find high and low values
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{
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if (BinStream[i] > high)
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high = BinStream[i];
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else if (BinStream[i] < low)
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low = BinStream[i];
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}
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if ((high < 158) ){ //throw away static
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//PrintAndLog("no data found");
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return -2;
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}
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//25% fuzz in case highs and lows aren't clipped [marshmellow]
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high=(int)((high-128)*.75)+128;
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low= (int)((low-128)*.75)+128;
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//PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
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int lastBit = 0; //set first clock check
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uint32_t bitnum = 0; //output counter
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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
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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
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int iii = 0;
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uint32_t gLen = *BitLen;
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if (gLen > 3000) gLen=3000;
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uint8_t errCnt =0;
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uint32_t bestStart = *BitLen;
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uint32_t bestErrCnt = (*BitLen/1000);
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uint32_t maxErr = (*BitLen/1000);
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//PrintAndLog("DEBUG - lastbit - %d",lastBit);
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//loop to find first wave that works
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for (iii=0; iii < gLen; ++iii){
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if ((BinStream[iii]>=high)||(BinStream[iii]<=low)){
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lastBit=iii-*clk;
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errCnt=0;
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//loop through to see if this start location works
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for (i = iii; i < *BitLen; ++i) {
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if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
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lastBit+=*clk;
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} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
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//low found and we are expecting a bar
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lastBit+=*clk;
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} else {
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//mid value found or no bar supposed to be here
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if ((i-lastBit)>(*clk+tol)){
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//should have hit a high or low based on clock!!
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//debug
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//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);
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errCnt++;
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lastBit+=*clk;//skip over until hit too many errors
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if (errCnt>(maxErr)) break; //allow 1 error for every 1000 samples else start over
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}
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}
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if ((i-iii) >(400 * *clk)) break; //got plenty of bits
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}
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//we got more than 64 good bits and not all errors
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if ((((i-iii)/ *clk) > (64+errCnt)) && (errCnt<maxErr)) {
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//possible good read
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if (errCnt==0){
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bestStart=iii;
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bestErrCnt=errCnt;
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break; //great read - finish
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}
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if (errCnt<bestErrCnt){ //set this as new best run
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bestErrCnt=errCnt;
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bestStart = iii;
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}
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}
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}
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}
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if (bestErrCnt<maxErr){
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//best run is good enough set to best run and set overwrite BinStream
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iii=bestStart;
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lastBit=bestStart-*clk;
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bitnum=0;
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for (i = iii; i < *BitLen; ++i) {
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if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
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lastBit+=*clk;
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BinStream[bitnum] = *invert;
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bitnum++;
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} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
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//low found and we are expecting a bar
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lastBit+=*clk;
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BinStream[bitnum] = 1-*invert;
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bitnum++;
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} else {
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//mid value found or no bar supposed to be here
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if ((i-lastBit)>(*clk+tol)){
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//should have hit a high or low based on clock!!
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//debug
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//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);
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if (bitnum > 0){
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BinStream[bitnum]=77;
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bitnum++;
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}
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lastBit+=*clk;//skip over error
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}
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}
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if (bitnum >=400) break;
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}
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*BitLen=bitnum;
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} else{
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*invert=bestStart;
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*clk=iii;
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return -1;
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}
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return bestErrCnt;
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}
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//by marshmellow
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//take 10 and 01 and manchester decode
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//run through 2 times and take least errCnt
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int manrawdecode(uint8_t * BitStream, int *bitLen)
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{
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int bitnum=0;
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int errCnt =0;
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int i=1;
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int bestErr = 1000;
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int bestRun = 0;
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int ii=1;
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for (ii=1;ii<3;++ii){
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i=1;
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for (i=i+ii;i<*bitLen-2;i+=2){
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if(BitStream[i]==1 && (BitStream[i+1]==0)){
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} else if((BitStream[i]==0)&& BitStream[i+1]==1){
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} else {
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errCnt++;
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}
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if(bitnum>300) break;
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}
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if (bestErr>errCnt){
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bestErr=errCnt;
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bestRun=ii;
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}
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errCnt=0;
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}
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errCnt=bestErr;
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if (errCnt<20){
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ii=bestRun;
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i=1;
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for (i=i+ii;i<*bitLen-2;i+=2){
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if(BitStream[i]==1 && (BitStream[i+1]==0)){
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BitStream[bitnum++]=0;
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} else if((BitStream[i]==0)&& BitStream[i+1]==1){
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BitStream[bitnum++]=1;
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} else {
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BitStream[bitnum++]=77;
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//errCnt++;
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}
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if(bitnum>300) break;
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}
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*bitLen=bitnum;
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}
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return errCnt;
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}
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//by marshmellow
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//take 01 or 10 = 0 and 11 or 00 = 1
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int BiphaseRawDecode(uint8_t * BitStream, int *bitLen, int offset)
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{
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uint8_t bitnum=0;
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uint32_t errCnt =0;
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uint32_t i=1;
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i=offset;
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for (;i<*bitLen-2;i+=2){
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if((BitStream[i]==1 && BitStream[i+1]==0)||(BitStream[i]==0 && BitStream[i+1]==1)){
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BitStream[bitnum++]=1;
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} else if((BitStream[i]==0 && BitStream[i+1]==0)||(BitStream[i]==1 && BitStream[i+1]==1)){
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BitStream[bitnum++]=0;
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} else {
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BitStream[bitnum++]=77;
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errCnt++;
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}
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if(bitnum>250) break;
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}
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*bitLen=bitnum;
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return errCnt;
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}
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//by marshmellow
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//takes 2 arguments - clock and invert both as integers
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//attempts to demodulate ask only
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//prints binary found and saves in graphbuffer for further commands
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int askrawdemod(uint8_t *BinStream, int *bitLen,int *clk, int *invert)
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{
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uint32_t i;
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// int invert=0; //invert default
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int high = 0, low = 128;
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*clk=DetectASKClock(BinStream,*bitLen,*clk); //clock default
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uint8_t BitStream[502] = {0};
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if (*clk<8) *clk =64;
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if (*clk<32) *clk=32;
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if (*invert != 0 && *invert != 1) *invert =0;
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uint32_t initLoopMax = 200;
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if (initLoopMax>*bitLen) initLoopMax=*bitLen;
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// Detect high and lows
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for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values
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{
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if (BinStream[i] > high)
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high = BinStream[i];
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else if (BinStream[i] < low)
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low = BinStream[i];
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}
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if ((high < 158)){ //throw away static
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// PrintAndLog("no data found");
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return -2;
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}
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//25% fuzz in case highs and lows aren't clipped [marshmellow]
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high=(int)((high-128)*.75)+128;
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low= (int)((low-128)*.75)+128;
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//PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
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int lastBit = 0; //set first clock check
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uint32_t bitnum = 0; //output counter
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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
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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
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uint32_t iii = 0;
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uint32_t gLen = *bitLen;
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if (gLen > 500) gLen=500;
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uint8_t errCnt =0;
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uint32_t bestStart = *bitLen;
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uint32_t bestErrCnt = (*bitLen/1000);
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uint8_t midBit=0;
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//PrintAndLog("DEBUG - lastbit - %d",lastBit);
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//loop to find first wave that works
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for (iii=0; iii < gLen; ++iii){
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if ((BinStream[iii]>=high)||(BinStream[iii]<=low)){
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lastBit=iii-*clk;
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//loop through to see if this start location works
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for (i = iii; i < *bitLen; ++i) {
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if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
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lastBit+=*clk;
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BitStream[bitnum] = *invert;
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bitnum++;
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midBit=0;
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} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
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//low found and we are expecting a bar
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lastBit+=*clk;
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BitStream[bitnum] = 1-*invert;
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bitnum++;
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midBit=0;
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} else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
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//mid bar?
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midBit=1;
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BitStream[bitnum]= 1-*invert;
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bitnum++;
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} else if ((BinStream[i]>=high)&&(midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
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//mid bar?
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midBit=1;
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BitStream[bitnum]= *invert;
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bitnum++;
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} else if ((i-lastBit)>((*clk/2)+tol)&&(midBit==0)){
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//no mid bar found
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midBit=1;
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BitStream[bitnum]= BitStream[bitnum-1];
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bitnum++;
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} else {
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//mid value found or no bar supposed to be here
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if ((i-lastBit)>(*clk+tol)){
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//should have hit a high or low based on clock!!
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//debug
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//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);
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if (bitnum > 0){
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BitStream[bitnum]=77;
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bitnum++;
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}
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errCnt++;
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lastBit+=*clk;//skip over until hit too many errors
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if (errCnt>((*bitLen/1000))){ //allow 1 error for every 1000 samples else start over
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errCnt=0;
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bitnum=0;//start over
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break;
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}
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}
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}
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if (bitnum>500) break;
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}
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//we got more than 64 good bits and not all errors
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if ((bitnum > (64+errCnt)) && (errCnt<(*bitLen/1000))) {
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//possible good read
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if (errCnt==0) break; //great read - finish
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if (bestStart == iii) break; //if current run == bestErrCnt run (after exhausted testing) then finish
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if (errCnt<bestErrCnt){ //set this as new best run
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bestErrCnt=errCnt;
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bestStart = iii;
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}
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}
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}
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if (iii>=gLen){ //exhausted test
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//if there was a ok test go back to that one and re-run the best run (then dump after that run)
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if (bestErrCnt < (*bitLen/1000)) iii=bestStart;
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}
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}
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if (bitnum>16){
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// PrintAndLog("Data start pos:%d, lastBit:%d, stop pos:%d, numBits:%d",iii,lastBit,i,bitnum);
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//move BitStream back to BinStream
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// ClearGraph(0);
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for (i=0; i < bitnum; ++i){
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BinStream[i]=BitStream[i];
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}
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*bitLen=bitnum;
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// RepaintGraphWindow();
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//output
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// if (errCnt>0){
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// PrintAndLog("# Errors during Demoding (shown as 77 in bit stream): %d",errCnt);
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// }
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// PrintAndLog("ASK decoded bitstream:");
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// Now output the bitstream to the scrollback by line of 16 bits
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// printBitStream2(BitStream,bitnum);
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//int errCnt=0;
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//errCnt=manrawdemod(BitStream,bitnum);
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// Em410xDecode(Cmd);
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} else return -1;
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return errCnt;
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}
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//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
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size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
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{
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uint32_t last_transition = 0;
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uint32_t idx = 1;
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uint32_t maxVal=0;
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if (fchigh==0) fchigh=10;
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if (fclow==0) fclow=8;
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// we do care about the actual theshold value as sometimes near the center of the
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// wave we may get static that changes direction of wave for one value
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// if our value is too low it might affect the read. and if our tag or
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// antenna is weak a setting too high might not see anything. [marshmellow]
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if (size<100) return 0;
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for(idx=1; idx<100; idx++){
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if(maxVal<dest[idx]) maxVal = dest[idx];
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}
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// set close to the top of the wave threshold with 25% margin for error
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// less likely to get a false transition up there.
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// (but have to be careful not to go too high and miss some short waves)
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uint8_t threshold_value = (uint8_t)(((maxVal-128)*.75)+128);
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// idx=1;
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//uint8_t threshold_value = 127;
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// sync to first lo-hi transition, and threshold
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// Need to threshold first sample
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if(dest[0] < threshold_value) dest[0] = 0;
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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);
|
|
}
|
|
|
|
//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,
|
|
{
|
|
uint8_t lastval=dest[0];
|
|
uint32_t idx=0;
|
|
size_t numBits=0;
|
|
uint32_t n=1;
|
|
|
|
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;
|
|
}
|
|
//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;
|
|
}
|
|
// 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)
|
|
{
|
|
|
|
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++;
|
|
}
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
uint32_t bytebits_to_byte(uint8_t* src, int numbits)
|
|
{
|
|
uint32_t num = 0;
|
|
for(int i = 0 ; i < numbits ; i++)
|
|
{
|
|
num = (num << 1) | (*src);
|
|
src++;
|
|
}
|
|
return num;
|
|
}
|
|
|
|
int IOdemodFSK(uint8_t *dest, size_t size)
|
|
{
|
|
uint32_t idx=0;
|
|
//make sure buffer has data
|
|
if (size < 66) return -1;
|
|
//test samples are not just noise
|
|
uint8_t testMax=0;
|
|
for(idx=0;idx<65;idx++){
|
|
if (testMax<dest[idx]) testMax=dest[idx];
|
|
}
|
|
idx=0;
|
|
//if not just noise
|
|
if (testMax>20){
|
|
// 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?
|
|
//Index map
|
|
//0 10 20 30 40 50 60
|
|
//| | | | | | |
|
|
//01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
|
|
//-----------------------------------------------------------------------------
|
|
//00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
|
|
//
|
|
//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;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
// 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 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];
|
|
}
|
|
}
|
|
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=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];
|
|
}
|
|
}
|
|
}
|
|
int iii=0;
|
|
int best=0;
|
|
for (iii=0; iii<6;++iii){
|
|
if (errCnt[iii]<errCnt[best]){
|
|
best = iii;
|
|
}
|
|
}
|
|
return clk[best];
|
|
}
|