RfidResearchGroup/proxmark3
1
1
Fork 0
mirror of https://github.com/RfidResearchGroup/proxmark3.git synced 2024-11-10 17:49:32 +08:00
Code Issues Projects Releases Packages Wiki Activity
proxmark3/common/lfdemod.c
marshmellow42 3bc66a96fe added PSK2 to lf simpsk 
testing still ongoing.
2015-02-21 22:54:52 -05:00

1654 lines
50 KiB
C
Raw Blame History

//-----------------------------------------------------------------------------
// Copyright (C) 2014
//
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Low frequency demod/decode commands
//-----------------------------------------------------------------------------
#include <stdlib.h>
#include <string.h>
#include "lfdemod.h"
uint8_t justNoise(uint8_t *BitStream, size_t size)
{
static const uint8_t THRESHOLD = 123;
//test samples are not just noise
uint8_t justNoise1 = 1;
for(size_t idx=0; idx < size && justNoise1 ;idx++){
justNoise1 = BitStream[idx] < THRESHOLD;
}
return justNoise1;
}
//by marshmellow
//get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
{
*high=0;
*low=255;
// get high and low thresholds
for (int i=0; i < size; i++){
if (BitStream[i] > *high) *high = BitStream[i];
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);
return 1;
}
// by marshmellow
// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
// returns 1 if passed
uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
{
uint8_t ans = 0;
for (uint8_t i = 0; i < bitLen; i++){
ans ^= ((bits >> i) & 1);
}
//PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
return (ans == pType);
}
//by marshmellow
//search for given preamble in given BitStream and return startIndex and length
uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
{
uint8_t foundCnt=0;
for (int idx=0; idx < *size - pLen; idx++){
if (memcmp(BitStream+idx, preamble, pLen) == 0){
//first index found
foundCnt++;
if (foundCnt == 1){
*startIdx = idx;
}
if (foundCnt == 2){
*size = idx - *startIdx;
return 1;
}
}
}
return 0;
}
//by marshmellow
//takes 1s and 0s and searches for EM410x format - output EM ID
uint64_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx)
{
//no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
// otherwise could be a void with no arguments
//set defaults
uint64_t lo=0;
uint32_t i = 0;
if (BitStream[1]>1){ //allow only 1s and 0s
// PrintAndLog("no data found");
return 0;
}
// 111111111 bit pattern represent start of frame
uint8_t preamble[] = {1,1,1,1,1,1,1,1,1};
uint32_t idx = 0;
uint32_t parityBits = 0;
uint8_t errChk = 0;
*startIdx = 0;
for (uint8_t extraBitChk=0; extraBitChk<5; extraBitChk++){
errChk = preambleSearch(BitStream+extraBitChk+*startIdx, preamble, sizeof(preamble), size, startIdx);
if (errChk == 0) return 0;
idx = *startIdx + 9;
for (i=0; i<10;i++){ //loop through 10 sets of 5 bits (50-10p = 40 bits)
parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
//check even parity
if (parityTest(parityBits, 5, 0) == 0){
//parity failed try next bit (in the case of 1111111111) but last 9 = preamble
startIdx++;
errChk = 0;
break;
}
//set uint64 with ID from BitStream
for (uint8_t ii=0; ii<4; ii++){
lo = (lo << 1LL) | (BitStream[(i*5)+ii+idx]);
}
}
if (errChk != 0) return lo;
//skip last 5 bit parity test for simplicity.
// *size = 64;
}
return 0;
}
//by marshmellow
//takes 3 arguments - clock, invert, maxErr as integers
//attempts to demodulate ask while decoding manchester
//prints binary found and saves in graphbuffer for further commands
int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr)
{
int i;
//int clk2=*clk;
int start = DetectASKClock(BinStream, *size, clk, 20); //clock default
if (*clk==0) return -3;
if (start < 0) return -3;
// if autodetected too low then adjust //MAY NEED ADJUSTMENT
//if (clk2==0 && *clk<8) *clk =64;
//if (clk2==0 && *clk<32) *clk=32;
if (*invert != 0 && *invert != 1) *invert=0;
uint32_t initLoopMax = 200;
if (initLoopMax > *size) initLoopMax=*size;
// Detect high and lows
// 25% fuzz in case highs and lows aren't clipped [marshmellow]
int high, low, ans;
ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
if (ans<1) return -2; //just noise
// PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
int lastBit = 0; //set first clock check
uint32_t bitnum = 0; //output counter
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
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
int iii = 0;
uint32_t gLen = *size;
if (gLen > 3000) gLen=3000;
uint8_t errCnt =0;
uint16_t MaxBits = 500;
uint32_t bestStart = *size;
int bestErrCnt = maxErr+1;
// PrintAndLog("DEBUG - lastbit - %d",lastBit);
// loop to find first wave that works
for (iii=0; iii < gLen; ++iii){
if ((BinStream[iii] >= high) || (BinStream[iii] <= low)){
lastBit=iii-*clk;
errCnt=0;
// loop through to see if this start location works
for (i = iii; i < *size; ++i) {
if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
lastBit+=*clk;
} else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
//low found and we are expecting a bar
lastBit+=*clk;
} else {
//mid value found or no bar supposed to be here
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)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
errCnt++;
lastBit+=*clk;//skip over until hit too many errors
if (errCnt>(maxErr)) break; //allow 1 error for every 1000 samples else start over
}
}
if ((i-iii) >(MaxBits * *clk)) break; //got plenty of 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;
}
}
}
}
if (bestErrCnt<=maxErr){
//best run is good enough set to best run and set overwrite BinStream
iii=bestStart;
lastBit = bestStart - *clk;
bitnum=0;
for (i = iii; i < *size; ++i) {
if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
lastBit += *clk;
BinStream[bitnum] = *invert;
bitnum++;
} else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
//low found and we are expecting a bar
lastBit+=*clk;
BinStream[bitnum] = 1-*invert;
bitnum++;
} else {
//mid value found or no bar supposed to be here
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)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
if (bitnum > 0){
BinStream[bitnum]=77;
bitnum++;
}
lastBit+=*clk;//skip over error
}
}
if (bitnum >=MaxBits) break;
}
*size=bitnum;
} else{
*invert=bestStart;
*clk=iii;
return -1;
}
return bestErrCnt;
}
//by marshmellow
//encode binary data into binary manchester
int ManchesterEncode(uint8_t *BitStream, size_t size)
{
size_t modIdx=20000, i=0;
if (size>modIdx) return -1;
for (size_t idx=0; idx < size; idx++){
BitStream[idx+modIdx++] = BitStream[idx];
BitStream[idx+modIdx++] = BitStream[idx]^1;
}
for (; i<(size*2); i++){
BitStream[i] = BitStream[i+20000];
}
return i;
}
//by marshmellow
//take 10 and 01 and manchester decode
//run through 2 times and take least errCnt
int manrawdecode(uint8_t * BitStream, size_t *size)
{
uint16_t bitnum=0;
uint16_t MaxBits = 500;
uint16_t errCnt = 0;
size_t i=1;
uint16_t bestErr = 1000;
uint16_t bestRun = 0;
size_t ii=1;
if (size == 0) return -1;
for (ii=1;ii<3;++ii){
i=1;
for (i=i+ii;i<*size-2;i+=2){
if(BitStream[i]==1 && (BitStream[i+1]==0)){
} else if((BitStream[i]==0)&& BitStream[i+1]==1){
} else {
errCnt++;
}
if(bitnum>MaxBits) break;
}
if (bestErr>errCnt){
bestErr=errCnt;
bestRun=ii;
}
errCnt=0;
}
errCnt=bestErr;
if (errCnt<20){
ii=bestRun;
i=1;
for (i=i+ii; 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;
//errCnt++;
}
if(bitnum>MaxBits) break;
}
*size=bitnum;
}
return errCnt;
}
//by marshmellow
//take 01 or 10 = 0 and 11 or 00 = 1
int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
{
uint16_t bitnum=0;
uint32_t errCnt =0;
uint32_t i;
uint16_t MaxBits=500;
i=offset;
if (size == 0) return -1;
for (;i<*size-2; i+=2){
if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
BitStream[bitnum++]=1^invert;
} else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
BitStream[bitnum++]=invert;
} else {
BitStream[bitnum++]=77;
errCnt++;
}
if(bitnum>MaxBits) break;
}
*size=bitnum;
return errCnt;
}
//by marshmellow
void askAmp(uint8_t *BitStream, size_t size)
{
int shift = 127;
int shiftedVal=0;
for(int i = 1; i<size; i++){
if (BitStream[i]-BitStream[i-1]>=30) //large jump up
shift=127;
else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
shift=-127;
shiftedVal=BitStream[i]+shift;
if (shiftedVal>255)
shiftedVal=255;
else if (shiftedVal<0)
shiftedVal=0;
BitStream[i-1] = shiftedVal;
}
return;
}
//by marshmellow
//takes 3 arguments - clock, invert and maxErr as integers
//attempts to demodulate ask only
//prints binary found and saves in graphbuffer for further commands
int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp)
{
uint32_t i;
if (*size==0) return -1;
int start = DetectASKClock(BinStream, *size, clk, 20); //clock default
if (*clk==0) return -1;
if (start<0) return -1;
if (*invert != 0 && *invert != 1) *invert =0;
uint32_t initLoopMax = 200;
if (initLoopMax > *size) initLoopMax=*size;
// Detect high and lows
//25% fuzz in case highs and lows aren't clipped [marshmellow]
int high, low, ans;
if (amp==1) askAmp(BinStream, *size);
ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
if (ans<1) return -1; //just noise
//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 = 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=0; //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 = *size;
if (gLen > 500) gLen=500;
uint8_t errCnt =0;
uint32_t bestStart = *size;
uint32_t bestErrCnt = maxErr; //(*size/1000);
uint8_t midBit=0;
uint16_t MaxBits=1000;
//PrintAndLog("DEBUG - lastbit - %d",lastBit);
//loop to find first wave that works
for (iii=start; iii < gLen; ++iii){
if ((BinStream[iii]>=high) || (BinStream[iii]<=low)){
lastBit=iii-*clk;
errCnt=0;
//loop through to see if this start location works
for (i = iii; i < *size; ++i) {
if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
lastBit+=*clk;
midBit=0;
} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
//low found and we are expecting a bar
lastBit+=*clk;
midBit=0;
} else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
//mid bar?
midBit=1;
} else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
//mid bar?
midBit=1;
} else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
//no mid bar found
midBit=1;
} else {
//mid value found or no bar supposed to be here
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)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
errCnt++;
lastBit+=*clk;//skip over until hit too many errors
if (errCnt > maxErr){
//errCnt=0;
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;
}
}
}
}
if (bestErrCnt<=maxErr){
//best run is good enough - set to best run and overwrite BinStream
iii = bestStart;
lastBit = bestStart - *clk;
bitnum=0;
for (i = iii; i < *size; ++i) {
if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
lastBit += *clk;
BinStream[bitnum] = *invert;
bitnum++;
midBit=0;
} else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
//low found and we are expecting a bar
lastBit+=*clk;
BinStream[bitnum] = 1 - *invert;
bitnum++;
midBit=0;
} else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
//mid bar?
midBit=1;
BinStream[bitnum] = 1 - *invert;
bitnum++;
} else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
//mid bar?
midBit=1;
BinStream[bitnum] = *invert;
bitnum++;
} else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
//no mid bar found
midBit=1;
if (bitnum!=0) BinStream[bitnum] = BinStream[bitnum-1];
bitnum++;
} else {
//mid value found or no bar supposed to be here
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)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
if (bitnum > 0){
BinStream[bitnum]=77;
bitnum++;
}
lastBit+=*clk;//skip over error
}
}
if (bitnum >= MaxBits) break;
}
*size=bitnum;
} else{
*invert=bestStart;
*clk=iii;
return -1;
}
return bestErrCnt;
}
//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
{
uint32_t last_transition = 0;
uint32_t idx = 1;
//uint32_t maxVal=0;
if (fchigh==0) fchigh=10;
if (fclow==0) fclow=8;
//set the threshold close to 0 (graph) or 128 std to avoid static
uint8_t threshold_value = 123;
// sync to first lo-hi transition, and threshold
// Need to threshold first sample
if(dest[0] < threshold_value) dest[0] = 0;
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 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));
} else {// 0->1 crossing
n=myround2((float)(n+1)/((float)(rfLen-1)/(float)fchigh)); //-1 for fudge factor
}
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)
{
if (justNoise(dest, *size)) return -1;
size_t numStart=0, size2=*size, startIdx=0;
// FSK demodulator
*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
if (*size < 96) return -2;
// 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
uint8_t preamble[] = {0,0,0,1,1,1,0,1};
// find bitstring in array
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -3; //preamble not found
numStart = startIdx + sizeof(preamble);
// final loop, go over previously decoded FSK data and manchester decode into usable tag ID
for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
if (dest[idx] == dest[idx+1]){
return -4; //not manchester data
}
*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)|1;
else // 0 1
*lo=(*lo<<1)|0;
}
return (int)startIdx;
}
// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
{
if (justNoise(dest, *size)) return -1;
size_t numStart=0, size2=*size, startIdx=0;
// FSK demodulator
*size = fskdemod(dest, size2,50,1,10,8); //fsk2a
if (*size < 96) return -2;
// 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
uint8_t preamble[] = {0,0,0,0,1,1,1,1};
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -3; //preamble not found
numStart = startIdx + sizeof(preamble);
// final loop, go over previously decoded FSK data and manchester decode into usable tag ID
for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
if (dest[idx] == dest[idx+1])
return -4; //not manchester data
*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)|1;
else // 0 1
*lo=(*lo<<1)|0;
}
return (int)startIdx;
}
uint32_t bytebits_to_byte(uint8_t* src, size_t 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)
{
if (justNoise(dest, size)) return -1;
//make sure buffer has data
if (size < 66*64) return -2;
// FSK demodulator
size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
if (size < 65) return -3; //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
size_t startIdx = 0;
uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
if (errChk == 0) return -4; //preamble not found
if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
//confirmed proper separator bits found
//return start position
return (int) startIdx;
}
return -5;
}
// by marshmellow
// takes a array of binary values, start position, length of bits per parity (includes parity bit),
// Parity Type (1 for odd 0 for even), and binary Length (length to run)
size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
{
uint32_t parityWd = 0;
size_t j = 0, bitCnt = 0;
for (int word = 0; word < (bLen); word+=pLen){
for (int bit=0; bit < pLen; bit++){
parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
BitStream[j++] = (BitStream[startIdx+word+bit]);
}
j--;
// if parity fails then return 0
if (parityTest(parityWd, pLen, pType) == 0) return -1;
bitCnt+=(pLen-1);
parityWd = 0;
}
// if we got here then all the parities passed
//return ID start index and size
return bitCnt;
}
// by marshmellow
// FSK Demod then try to locate an AWID ID
int AWIDdemodFSK(uint8_t *dest, size_t *size)
{
//make sure buffer has enough data
if (*size < 96*50) return -1;
if (justNoise(dest, *size)) return -2;
// FSK demodulator
*size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
if (*size < 96) return -3; //did we get a good demod?
uint8_t preamble[] = {0,0,0,0,0,0,0,1};
size_t startIdx = 0;
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -4; //preamble not found
if (*size != 96) return -5;
return (int)startIdx;
}
// by marshmellow
// FSK Demod then try to locate an Farpointe Data (pyramid) ID
int PyramiddemodFSK(uint8_t *dest, size_t *size)
{
//make sure buffer has data
if (*size < 128*50) return -5;
//test samples are not just noise
if (justNoise(dest, *size)) return -1;
// FSK demodulator
*size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
if (*size < 128) return -2; //did we get a good demod?
uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
size_t startIdx = 0;
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -4; //preamble not found
if (*size != 128) return -3;
return (int)startIdx;
}
uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, int high, int low)
{
uint8_t allPeaks=1;
uint16_t cntPeaks=0;
for (size_t i=20; i<255; i++){
if (dest[i]>low && dest[i]<high)
allPeaks=0;
else
cntPeaks++;
}
if (allPeaks==0){
if (cntPeaks>190) return 1;
}
return allPeaks;
}
// 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?
// 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)
{
int i=0;
int clk[]={8,16,32,40,50,64,100,128,256};
int loopCnt = 256; //don't need to loop through entire array...
if (size == 0) return -1;
if (size<loopCnt) loopCnt = size;
//if we already have a valid clock quit
for (;i<8;++i)
if (clk[i] == *clock) return 0;
//get high and low peak
int peak, low;
getHiLo(dest, loopCnt, &peak, &low, 75, 75);
//test for large clean peaks
if (DetectCleanAskWave(dest, size, peak, low)==1){
uint16_t fcTest=0;
uint8_t mostFC=0;
fcTest=countFC(dest, size, &mostFC);
uint8_t fc1 = fcTest >> 8;
uint8_t fc2 = fcTest & 0xFF;
for (i=0; i<8; i++){
if (clk[i] == fc1) {
*clock=fc1;
return 0;
}
if (clk[i] == fc2) {
*clock=fc2;
return 0;
}
}
}
int ii;
int clkCnt;
int tol = 0;
int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
int bestStart[]={0,0,0,0,0,0,0,0,0};
int errCnt=0;
//test each valid clock from smallest to greatest to see which lines up
for(clkCnt=0; clkCnt < 8; clkCnt++){
if (clk[clkCnt] == 32){
tol=1;
}else{
tol=0;
}
bestErr[clkCnt]=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=0;
// now that we have the first one lined up test rest of wave array
for (i=0; i<((int)((size-ii-tol)/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++;
}
}
//if we found no errors then we can stop here
// this is correct one - return this clock
//PrintAndLog("DEBUG: clk %d, err %d, ii %d, i %d",clk[clkCnt],errCnt,ii,i);
if(errCnt==0 && clkCnt<6) {
*clock = clk[clkCnt];
return ii;
}
//if we found errors see if it is lowest so far and save it as best run
if(errCnt<bestErr[clkCnt]){
bestErr[clkCnt]=errCnt;
bestStart[clkCnt]=ii;
}
}
}
}
uint8_t iii=0;
uint8_t best=0;
for (iii=0; iii<8; ++iii){
if (bestErr[iii]<bestErr[best]){
if (bestErr[iii]==0) bestErr[iii]=1;
// current best bit to error ratio vs new bit to error ratio
if (((size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii]) ){
best = iii;
}
}
}
if (bestErr[best]>maxErr) return -1;
*clock=clk[best];
return bestStart[best];
}
//by marshmellow
//detect psk clock by reading each phase shift
// a phase shift is determined by measuring the sample length of each wave
int DetectPSKClock(uint8_t dest[], size_t size, int clock)
{
uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
uint16_t loopCnt = 4096; //don't need to loop through entire array...
if (size == 0) return 0;
if (size<loopCnt) loopCnt = size;
//if we already have a valid clock quit
size_t i=1;
for (; i < 8; ++i)
if (clk[i] == clock) return clock;
size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
countFC(dest, size, &fc);
//PrintAndLog("DEBUG: FC: %d",fc);
//find first full wave
for (i=0; i<loopCnt; i++){
if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
if (waveStart == 0) {
waveStart = i+1;
//PrintAndLog("DEBUG: waveStart: %d",waveStart);
} else {
waveEnd = i+1;
//PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
waveLenCnt = waveEnd-waveStart;
if (waveLenCnt > fc){
firstFullWave = waveStart;
fullWaveLen=waveLenCnt;
break;
}
waveStart=0;
}
}
}
//PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
//test each valid clock from greatest to smallest to see which lines up
for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
lastClkBit = firstFullWave; //set end of wave as clock align
waveStart = 0;
errCnt=0;
peakcnt=0;
//PrintAndLog("DEBUG: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
//top edge of wave = start of new wave
if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
if (waveStart == 0) {
waveStart = i+1;
waveLenCnt=0;
} else { //waveEnd
waveEnd = i+1;
waveLenCnt = waveEnd-waveStart;
if (waveLenCnt > fc){
//if this wave is a phase shift
//PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, ii: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,ii+1,fc);
if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
peakcnt++;
lastClkBit+=clk[clkCnt];
} else if (i<lastClkBit+8){
//noise after a phase shift - ignore
} else { //phase shift before supposed to based on clock
errCnt++;
}
} else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
}
waveStart=i+1;
}
}
}
if (errCnt == 0){
return clk[clkCnt];
}
if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
}
//all tested with errors
//return the highest clk with the most peaks found
uint8_t best=7;
for (i=7; i>=1; i--){
if (peaksdet[i] > peaksdet[best]) {
best = i;
}
//PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
}
return clk[best];
}
//by marshmellow
//detect nrz clock by reading #peaks vs no peaks(or errors)
int DetectNRZClock(uint8_t dest[], size_t size, int clock)
{
int i=0;
int clk[]={8,16,32,40,50,64,100,128,256};
int loopCnt = 4096; //don't need to loop through entire array...
if (size == 0) return 0;
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
int peak, low;
getHiLo(dest, loopCnt, &peak, &low, 75, 75);
//PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
int ii;
uint8_t clkCnt;
uint8_t tol = 0;
int peakcnt=0;
int peaksdet[]={0,0,0,0,0,0,0,0};
int maxPeak=0;
//test for large clipped waves
for (i=0; i<loopCnt; i++){
if (dest[i] >= peak || dest[i] <= low){
peakcnt++;
} else {
if (peakcnt>0 && maxPeak < peakcnt){
maxPeak = peakcnt;
}
peakcnt=0;
}
}
peakcnt=0;
//test each valid clock from smallest to greatest to see which lines up
for(clkCnt=0; clkCnt < 8; ++clkCnt){
//ignore clocks smaller than largest peak
if (clk[clkCnt]<maxPeak) continue;
//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)){
peakcnt=0;
// now that we have the first one lined up test rest of wave array
for (i=0; i < ((int)((size-ii-tol)/clk[clkCnt])-1); ++i){
if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
peakcnt++;
}
}
if(peakcnt>peaksdet[clkCnt]) {
peaksdet[clkCnt]=peakcnt;
}
}
}
}
int iii=7;
int best=0;
for (iii=7; iii > 0; iii--){
if (peaksdet[iii] > peaksdet[best]){
best = iii;
}
//PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
}
return clk[best];
}
// by marshmellow
// convert psk1 demod to psk2 demod
// only transition waves are 1s
void psk1TOpsk2(uint8_t *BitStream, size_t size)
{
size_t i=1;
uint8_t lastBit=BitStream[0];
for (; i<size; i++){
if (lastBit!=BitStream[i]){
lastBit=BitStream[i];
BitStream[i]=1;
} else {
BitStream[i]=0;
}
}
return;
}
// by marshmellow
// convert psk2 demod to psk1 demod
// from only transition waves are 1s to phase shifts change bit
void psk2TOpsk1(uint8_t *BitStream, size_t size)
{
size_t i;
uint8_t phase=BitStream[0];
//uint8_t lastBit=BitStream[0];
for (i=1; i<size; i++){
if (phase!=BitStream[i]){
phase ^=1;
}
BitStream[i]=phase;
}
return;
}
// redesigned by marshmellow adjusted from existing decode functions
// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
{
//26 bit 40134 format (don't know other formats)
int i;
int long_wait=29;//29 leading zeros in format
int start;
int first = 0;
int first2 = 0;
int bitCnt = 0;
int ii;
// Finding the start of a UID
for (start = 0; start <= *size - 250; start++) {
first = bitStream[start];
for (i = start; i < start + long_wait; i++) {
if (bitStream[i] != first) {
break;
}
}
if (i == (start + long_wait)) {
break;
}
}
if (start == *size - 250 + 1) {
// did not find start sequence
return -1;
}
// Inverting signal if needed
if (first == 1) {
for (i = start; i < *size; i++) {
bitStream[i] = !bitStream[i];
}
*invert = 1;
}else *invert=0;
int iii;
//found start once now test length by finding next one
for (ii=start+29; ii <= *size - 250; ii++) {
first2 = bitStream[ii];
for (iii = ii; iii < ii + long_wait; iii++) {
if (bitStream[iii] != first2) {
break;
}
}
if (iii == (ii + long_wait)) {
break;
}
}
if (ii== *size - 250 + 1){
// did not find second start sequence
return -2;
}
bitCnt=ii-start;
// Dumping UID
i = start;
for (ii = 0; ii < bitCnt; ii++) {
bitStream[ii] = bitStream[i++];
}
*size=bitCnt;
return 1;
}
// by marshmellow - demodulate NRZ wave (both similar enough)
// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
// there probably is a much simpler way to do this....
int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int maxErr)
{
if (justNoise(dest, *size)) return -1;
*clk = DetectNRZClock(dest, *size, *clk);
if (*clk==0) return -2;
uint32_t i;
int high, low, ans;
ans = getHiLo(dest, 1260, &high, &low, 75, 75); //25% fuzz on high 25% fuzz on low
if (ans<1) return -2; //just noise
uint32_t gLen = 256;
if (gLen>*size) gLen = *size;
int lastBit = 0; //set first clock check
uint32_t bitnum = 0; //output counter
uint8_t tol = 1; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
uint32_t iii = 0;
uint16_t errCnt =0;
uint16_t MaxBits = 1000;
uint32_t bestErrCnt = maxErr+1;
uint32_t bestPeakCnt = 0;
uint32_t bestPeakStart=0;
uint8_t curBit=0;
uint8_t bitHigh=0;
uint8_t errBitHigh=0;
uint16_t peakCnt=0;
uint8_t ignoreWindow=4;
uint8_t ignoreCnt=ignoreWindow; //in case of noice near peak
//loop to find first wave that works - align to clock
for (iii=0; iii < gLen; ++iii){
if ((dest[iii]>=high) || (dest[iii]<=low)){
lastBit=iii-*clk;
peakCnt=0;
errCnt=0;
bitnum=0;
//loop through to see if this start location works
for (i = iii; i < *size; ++i) {
//if we found a high bar and we are at a clock bit
if ((dest[i]>=high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
bitHigh=1;
lastBit+=*clk;
bitnum++;
peakCnt++;
errBitHigh=0;
ignoreCnt=ignoreWindow;
//else if low bar found and we are at a clock point
}else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
bitHigh=1;
lastBit+=*clk;
bitnum++;
peakCnt++;
errBitHigh=0;
ignoreCnt=ignoreWindow;
//else if no bars found
}else if(dest[i] < high && dest[i] > low) {
if (ignoreCnt==0){
bitHigh=0;
if (errBitHigh==1){
errCnt++;
}
errBitHigh=0;
} else {
ignoreCnt--;
}
//if we are past a clock point
if (i >= lastBit+*clk+tol){ //clock val
lastBit+=*clk;
bitnum++;
}
//else if bar found but we are not at a clock bit and we did not just have a clock bit
}else if ((dest[i]>=high || dest[i]<=low) && (i<lastBit+*clk-tol || i>lastBit+*clk+tol) && (bitHigh==0)){
//error bar found no clock...
errBitHigh=1;
}
if (bitnum>=MaxBits) break;
}
//we got more than 64 good bits and not all errors
if (bitnum > (64) && (errCnt <= (maxErr))) {
//possible good read
if (errCnt == 0){
//bestStart = iii;
bestErrCnt = errCnt;
bestPeakCnt = peakCnt;
bestPeakStart = iii;
break; //great read - finish
}
if (errCnt < bestErrCnt){ //set this as new best run
bestErrCnt = errCnt;
//bestStart = iii;
}
if (peakCnt > bestPeakCnt){
bestPeakCnt=peakCnt;
bestPeakStart=iii;
}
}
}
}
//PrintAndLog("DEBUG: bestErrCnt: %d, maxErr: %d, bestStart: %d, bestPeakCnt: %d, bestPeakStart: %d",bestErrCnt,maxErr,bestStart,bestPeakCnt,bestPeakStart);
if (bestErrCnt <= maxErr){
//best run is good enough set to best run and set overwrite BinStream
iii=bestPeakStart;
lastBit=bestPeakStart-*clk;
bitnum=0;
for (i = iii; i < *size; ++i) {
//if we found a high bar and we are at a clock bit
if ((dest[i] >= high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
bitHigh=1;
lastBit+=*clk;
curBit=1-*invert;
dest[bitnum]=curBit;
bitnum++;
errBitHigh=0;
ignoreCnt=ignoreWindow;
//else if low bar found and we are at a clock point
}else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
bitHigh=1;
lastBit+=*clk;
curBit=*invert;
dest[bitnum]=curBit;
bitnum++;
errBitHigh=0;
ignoreCnt=ignoreWindow;
//else if no bars found
}else if(dest[i]<high && dest[i]>low) {
if (ignoreCnt==0){
bitHigh=0;
//if peak is done was it an error peak?
if (errBitHigh==1){
dest[bitnum]=77;
bitnum++;
errCnt++;
}
errBitHigh=0;
} else {
ignoreCnt--;
}
//if we are past a clock point
if (i>=lastBit+*clk+tol){ //clock val
lastBit+=*clk;
dest[bitnum]=curBit;
bitnum++;
}
//else if bar found but we are not at a clock bit and we did not just have a clock bit
}else if ((dest[i]>=high || dest[i]<=low) && ((i<lastBit+*clk-tol) || (i>lastBit+*clk+tol)) && (bitHigh==0)){
//error bar found no clock...
errBitHigh=1;
}
if (bitnum >= MaxBits) break;
}
*size=bitnum;
} else{
*size=bitnum;
return -1;
}
if (bitnum>16){
*size=bitnum;
} else return -1;
return errCnt;
}
//by marshmellow
//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)
{
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 lastFCcnt=0;
uint32_t fcCounter = 0;
uint16_t rfCounter = 0;
uint8_t firstBitFnd = 0;
size_t i;
if (size == 0) return 0;
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-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 peak
fcCounter++;
rfCounter++;
// 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<15; ii++){
if (rfLens[ii]==rfCounter){
rfCnts[ii]++;
rfCounter=0;
break;
}
}
if (rfCounter>0 && rfLensFnd<15){
//PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
rfCnts[rfLensFnd]++;
rfLens[rfLensFnd++]=rfCounter;
}
} else {
firstBitFnd++;
}
rfCounter=0;
lastFCcnt=fcCounter;
}
fcCounter=0;
} else {
// count sample
fcCounter++;
rfCounter++;
}
}
uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
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 (rfCnts[i]>rfCnts[rfHighest]){
rfHighest3=rfHighest2;
rfHighest2=rfHighest;
rfHighest=i;
} else if(rfCnts[i]>rfCnts[rfHighest2]){
rfHighest3=rfHighest2;
rfHighest2=i;
} else if(rfCnts[i]>rfCnts[rfHighest3]){
rfHighest3=i;
}
}
// 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
int ii=7;
for (; ii>=0; ii--){
if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
break;
}
}
}
}
if (ii<0) return 0; // oops we went too far
return clk[ii];
}
//by marshmellow
//countFC is to detect the field clock lengths.
//counts and returns the 2 most common wave lengths
//mainly used for FSK field clock detection
uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t *mostFC)
{
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;
if (size == 0) return 0;
// 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]){
fcH=fcLens[best1];
fcL=fcLens[best2];
} else{
fcH=fcLens[best2];
fcL=fcLens[best1];
}
*mostFC=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;
}
//by marshmellow
//countPSK_FC is to detect the psk carrier clock length.
//counts and returns the 1 most common wave length
uint8_t countPSK_FC(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;
uint32_t fcCounter = 0;
size_t i;
if (size == 0) return 0;
// 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++;
// 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;
uint16_t maxCnt1=0;
// go through fclens and find which ones are bigest
for (i=0; i<10; i++){
//PrintAndLog("DEBUG: FC %d, Cnt %d",fcLens[i],fcCnts[i]);
// get the best FC value
if (fcCnts[i]>maxCnt1) {
maxCnt1=fcCnts[i];
best1=i;
}
}
return fcLens[best1];
}
//by marshmellow - demodulate PSK1 wave
//uses wave lengths (# Samples)
int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
{
uint16_t loopCnt = 4096; //don't need to loop through entire array...
if (size == 0) return -1;
if (*size<loopCnt) loopCnt = *size;
uint8_t curPhase = *invert;
size_t i, waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
uint8_t fc=0, fullWaveLen=0, tol=1;
uint16_t errCnt=0, waveLenCnt=0;
fc = countPSK_FC(dest, *size);
if (fc!=2 && fc!=4 && fc!=8) return -1;
//PrintAndLog("DEBUG: FC: %d",fc);
*clock = DetectPSKClock(dest, *size, *clock);
if (*clock==0) return -1;
int avgWaveVal=0, lastAvgWaveVal=0;
//find first full wave
for (i=0; i<loopCnt; i++){
if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
if (waveStart == 0) {
waveStart = i+1;
avgWaveVal=dest[i+1];
//PrintAndLog("DEBUG: waveStart: %d",waveStart);
} else {
waveEnd = i+1;
//PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
waveLenCnt = waveEnd-waveStart;
lastAvgWaveVal = avgWaveVal/waveLenCnt;
if (waveLenCnt > fc){
firstFullWave = waveStart;
fullWaveLen=waveLenCnt;
//if average wave value is > graph 0 then it is an up wave or a 1
if (lastAvgWaveVal > 128) curPhase^=1;
break;
}
waveStart=0;
avgWaveVal=0;
}
}
avgWaveVal+=dest[i+1];
}
//PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
lastClkBit = firstFullWave; //set start of wave as clock align
waveStart = 0;
errCnt=0;
size_t numBits=0;
//PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
for (i = firstFullWave+fullWaveLen-1; i < *size-3; i++){
//top edge of wave = start of new wave
if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
if (waveStart == 0) {
waveStart = i+1;
waveLenCnt=0;
avgWaveVal = dest[i+1];
} else { //waveEnd
waveEnd = i+1;
waveLenCnt = waveEnd-waveStart;
lastAvgWaveVal = avgWaveVal/waveLenCnt;
if (waveLenCnt > fc){
//PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
//if this wave is a phase shift
//PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
curPhase^=1;
dest[numBits] = curPhase;
numBits++;
lastClkBit += *clock;
} else if (i<lastClkBit+10){
//noise after a phase shift - ignore
} else { //phase shift before supposed to based on clock
errCnt++;
dest[numBits] = 77;
numBits++;
}
} else if (i+1 > lastClkBit + *clock + tol + fc){
lastClkBit += *clock; //no phase shift but clock bit
dest[numBits] = curPhase;
numBits++;
}
avgWaveVal=0;
waveStart=i+1;
}
}
avgWaveVal+=dest[i+1];
}
*size = numBits;
return errCnt;
}
Reference in a new issue View git blame Copy permalink