proxmark3/common/lfdemod.c
marshmellow42 43591e6464 Add Smartcard functions (RDV4.0) (#646)
* allow common makefile options-defines

* remove non-existing file references

* Uncomment lcd option (still) not enabled by default

use Makefile_Enabled_Options.common
to enable lcd if desired.

* Add Smartcard Functions

* add smartcard to menu + make get atr work

sc is now functioning as far as my limited knowledge takes me

* sc cleanup - add init to all sc commands...

because cmds won't work until the first init happens.  (multiple inits
don't appear to affect it negatively)

* default options to exclude Smartcard

for main repo

* update changelog
2018-08-21 05:08:49 +02:00

1921 lines
67 KiB
C

//-----------------------------------------------------------------------------
// 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 - by marshmellow, holiman, iceman and
// many others who came before
//
// NOTES:
// LF Demod functions are placed here to allow the flexability to use client or
// device side. Most BUT NOT ALL of these functions are currently safe for
// device side use. (DetectST for example...)
//
// There are likely many improvements to the code that could be made, please
// make suggestions...
//
// we tried to include author comments so any questions could be directed to
// the source.
//
// There are 4 main sections of code below:
// Utilities Section:
// for general utilities used by multiple other functions
// Clock / Bitrate Detection Section:
// for clock detection functions for each modulation
// Modulation Demods &/or Decoding Section:
// for main general modulation demodulating and encoding decoding code.
// Tag format detection section:
// for detection of specific tag formats within demodulated data
//
// marshmellow
//-----------------------------------------------------------------------------
#include <string.h> // for memset, memcmp and size_t
#include "lfdemod.h"
#include <stdint.h> // for uint_32+
#include <stdbool.h> // for bool
#include "parity.h" // for parity test
//**********************************************************************************************
//---------------------------------Utilities Section--------------------------------------------
//**********************************************************************************************
#define LOWEST_DEFAULT_CLOCK 32
#define FSK_PSK_THRESHOLD 123
//to allow debug print calls when used not on device
void dummy(char *fmt, ...){}
#ifndef ON_DEVICE
#include "ui.h"
#include "cmdparser.h"
#include "cmddata.h"
#define prnt PrintAndLog
#else
uint8_t g_debugMode=0;
#define prnt dummy
#endif
uint8_t justNoise(uint8_t *BitStream, size_t size) {
//test samples are not just noise
uint8_t justNoise1 = 1;
for(size_t idx=0; idx < size && justNoise1 ;idx++){
justNoise1 = BitStream[idx] < FSK_PSK_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 (size_t i=0; i < size; i++){
if (BitStream[i] > *high) *high = BitStream[i];
if (BitStream[i] < *low) *low = BitStream[i];
}
if (*high < FSK_PSK_THRESHOLD) return -1; // just noise
*high = ((*high-128)*fuzzHi + 12800)/100;
*low = ((*low-128)*fuzzLo + 12800)/100;
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
bool parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
return oddparity32(bits) ^ pType;
}
// by marshmellow
// takes a array of binary values, start position, length of bits per parity (includes parity bit - MAX 32),
// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), 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 bitCnt = 0;
for (int word = 0; word < (bLen); word+=pLen) {
for (int bit=0; bit < pLen; bit++) {
if (word+bit >= bLen) break;
parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
BitStream[bitCnt++] = (BitStream[startIdx+word+bit]);
}
if (word+pLen > bLen) break;
bitCnt--; // overwrite parity with next data
// if parity fails then return 0
switch (pType) {
case 3: if (BitStream[bitCnt]==1) {return 0;} break; //should be 0 spacer bit
case 2: if (BitStream[bitCnt]==0) {return 0;} break; //should be 1 spacer bit
default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
}
parityWd = 0;
}
// if we got here then all the parities passed
//return size
return bitCnt;
}
// by marshmellow
// takes a array of binary values, length of bits per parity (includes parity bit),
// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) {
uint32_t parityWd = 0;
size_t j = 0, bitCnt = 0;
for (int word = 0; word < sourceLen; word+=pLen-1) {
for (int bit=0; bit < pLen-1; bit++){
parityWd = (parityWd << 1) | BitSource[word+bit];
dest[j++] = (BitSource[word+bit]);
}
// if parity fails then return 0
switch (pType) {
case 3: dest[j++]=0; break; // marker bit which should be a 0
case 2: dest[j++]=1; break; // marker bit which should be a 1
default:
dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
break;
}
bitCnt += pLen;
parityWd = 0;
}
// if we got here then all the parities passed
//return ID start index and size
return bitCnt;
}
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;
}
//least significant bit first
uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) {
uint32_t num = 0;
for(int i = 0 ; i < numbits ; i++)
{
num = (num << 1) | *(src + (numbits-(i+1)));
}
return num;
}
// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
// Sanity check. If preamble length is bigger than bitstream length.
if ( *size <= pLen ) return false;
uint8_t foundCnt = 0;
for (size_t idx = 0; idx < *size - pLen; idx++) {
if (memcmp(BitStream+idx, preamble, pLen) == 0) {
//first index found
foundCnt++;
if (foundCnt == 1) {
if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
*startIdx = idx;
if (findone) return true;
} else if (foundCnt == 2) {
*size = idx - *startIdx;
return true;
}
}
}
return false;
}
//by marshmellow
//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) {
return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
}
// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
size_t findModStart(uint8_t dest[], size_t size, uint8_t expWaveSize) {
size_t i = 0;
size_t waveSizeCnt = 0;
uint8_t thresholdCnt = 0;
bool isAboveThreshold = dest[i++] >= FSK_PSK_THRESHOLD;
for (; i < size-20; i++ ) {
if(dest[i] < FSK_PSK_THRESHOLD && isAboveThreshold) {
thresholdCnt++;
if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
isAboveThreshold = false;
waveSizeCnt = 0;
} else if (dest[i] >= FSK_PSK_THRESHOLD && !isAboveThreshold) {
thresholdCnt++;
if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
isAboveThreshold = true;
waveSizeCnt = 0;
} else {
waveSizeCnt++;
}
if (thresholdCnt > 10) break;
}
if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
return i;
}
int getClosestClock(int testclk) {
uint8_t fndClk[] = {8,16,32,40,50,64,128};
for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++)
if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1)
return fndClk[clkCnt];
return 0;
}
void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) {
while ((samples[*i] > low) && (*i < size))
*i+=1;
}
void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) {
while ((samples[*i] < high) && (*i < size))
*i+=1;
}
// load wave counters
bool loadWaveCounters(uint8_t samples[], size_t size, int lowToLowWaveLen[], int highToLowWaveLen[], int *waveCnt, int *skip, int *minClk, int *high, int *low) {
size_t i=0, firstLow, firstHigh;
size_t testsize = (size < 512) ? size : 512;
if ( getHiLo(samples, testsize, high, low, 80, 80) == -1 ) {
if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
return false; //just noise
}
// get to first full low to prime loop and skip incomplete first pulse
getNextHigh(samples, size, *high, &i);
getNextLow(samples, size, *low, &i);
*skip = i;
// populate tmpbuff buffer with pulse lengths
while (i < size) {
// measure from low to low
firstLow = i;
//find first high point for this wave
getNextHigh(samples, size, *high, &i);
firstHigh = i;
getNextLow(samples, size, *low, &i);
if (*waveCnt >= (size/LOWEST_DEFAULT_CLOCK))
break;
highToLowWaveLen[*waveCnt] = i - firstHigh; //first high to first low
lowToLowWaveLen[*waveCnt] = i - firstLow;
*waveCnt += 1;
if (i-firstLow < *minClk && i < size) {
*minClk = i - firstLow;
}
}
return true;
}
size_t pskFindFirstPhaseShift(uint8_t samples[], size_t size, uint8_t *curPhase, size_t waveStart, uint16_t fc, uint16_t *fullWaveLen) {
uint16_t loopCnt = (size+3 < 4096) ? size : 4096; //don't need to loop through entire array...
uint16_t avgWaveVal=0, lastAvgWaveVal=0;
size_t i = waveStart, waveEnd, waveLenCnt, firstFullWave;
for (; i<loopCnt; i++) {
// find peak // was "samples[i] + fc" but why? must have been used to weed out some wave error... removed..
if (samples[i] < samples[i+1] && samples[i+1] >= samples[i+2]){
waveEnd = i+1;
if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u", waveEnd, waveStart);
waveLenCnt = waveEnd-waveStart;
if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+8)){ //not first peak and is a large wave but not out of whack
lastAvgWaveVal = avgWaveVal/(waveLenCnt);
firstFullWave = waveStart;
*fullWaveLen = waveLenCnt;
//if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
if (lastAvgWaveVal > FSK_PSK_THRESHOLD) *curPhase ^= 1;
return firstFullWave;
}
waveStart = i+1;
avgWaveVal = 0;
}
avgWaveVal += samples[i+2];
}
return 0;
}
//by marshmellow
//amplify based on ask edge detection - not accurate enough to use all the time
void askAmp(uint8_t *BitStream, size_t size) {
uint8_t Last = 128;
for(size_t i = 1; i<size; i++){
if (BitStream[i]-BitStream[i-1]>=30) //large jump up
Last = 255;
else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
Last = 0;
BitStream[i-1] = Last;
}
return;
}
uint32_t manchesterEncode2Bytes(uint16_t datain) {
uint32_t output = 0;
uint8_t curBit = 0;
for (uint8_t i=0; i<16; i++) {
curBit = (datain >> (15-i) & 1);
output |= (1<<(((15-i)*2)+curBit));
}
return output;
}
//by marshmellow
//encode binary data into binary manchester
//NOTE: BitStream must have triple the size of "size" available in memory to do the swap
int ManchesterEncode(uint8_t *BitStream, size_t size) {
//allow up to 4K out (means BitStream must be at least 2048+4096 to handle the swap)
size = (size>2048) ? 2048 : size;
size_t modIdx = size;
size_t i;
for (size_t idx=0; idx < size; idx++){
BitStream[idx+modIdx++] = BitStream[idx];
BitStream[idx+modIdx++] = BitStream[idx]^1;
}
for (i=0; i<(size*2); i++){
BitStream[i] = BitStream[i+size];
}
return i;
}
// by marshmellow
// to detect a wave that has heavily clipped (clean) samples
uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) {
bool allArePeaks = true;
uint16_t cntPeaks=0;
size_t loopEnd = 512+160;
if (loopEnd > size) loopEnd = size;
for (size_t i=160; i<loopEnd; i++){
if (dest[i]>low && dest[i]<high)
allArePeaks = false;
else
cntPeaks++;
}
if (!allArePeaks){
if (cntPeaks > 300) return true;
}
return allArePeaks;
}
//**********************************************************************************************
//-------------------Clock / Bitrate Detection Section------------------------------------------
//**********************************************************************************************
// by marshmellow
// to help detect clocks on heavily clipped samples
// based on count of low to low
int DetectStrongAskClock(uint8_t dest[], size_t size, int high, int low, int *clock) {
size_t startwave;
size_t i = 100;
size_t minClk = 255;
int shortestWaveIdx = 0;
// get to first full low to prime loop and skip incomplete first pulse
getNextHigh(dest, size, high, &i);
getNextLow(dest, size, low, &i);
// loop through all samples
while (i < size) {
// measure from low to low
startwave = i;
getNextHigh(dest, size, high, &i);
getNextLow(dest, size, low, &i);
//get minimum measured distance
if (i-startwave < minClk && i < size) {
minClk = i - startwave;
shortestWaveIdx = startwave;
}
}
// set clock
if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk);
*clock = getClosestClock(minClk);
if (*clock == 0)
return 0;
return shortestWaveIdx;
}
// 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) {
size_t i=1;
uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
uint8_t clkEnd = 9;
uint8_t loopCnt = 255; //don't need to loop through entire array...
if (size <= loopCnt+60) return -1; //not enough samples
size -= 60; //sometimes there is a strange end wave - filter out this....
//if we already have a valid clock
uint8_t clockFnd=0;
for (;i<clkEnd;++i)
if (clk[i] == *clock) clockFnd = i;
//clock found but continue to find best startpos
//get high and low peak
int peak, low;
if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
//test for large clean peaks
if (!clockFnd){
if (DetectCleanAskWave(dest, size, peak, low)==1){
int ans = DetectStrongAskClock(dest, size, peak, low, clock);
if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
if (ans > 0) {
return ans; //return shortest wave start position
}
}
}
uint8_t ii;
uint8_t clkCnt, tol = 0;
uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
size_t errCnt = 0;
size_t arrLoc, loopEnd;
if (clockFnd>0) {
clkCnt = clockFnd;
clkEnd = clockFnd+1;
}
else clkCnt=1;
//test each valid clock from smallest to greatest to see which lines up
for(; clkCnt < clkEnd; clkCnt++){
if (clk[clkCnt] <= 32){
tol=1;
}else{
tol=0;
}
//if no errors allowed - keep start within the first clock
if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
bestErr[clkCnt]=1000;
//try lining up the peaks by moving starting point (try first few clocks)
for (ii=0; ii < loopCnt; ii++){
if (dest[ii] < peak && dest[ii] > low) continue;
errCnt=0;
// now that we have the first one lined up test rest of wave array
loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
for (i=0; i < loopEnd; ++i){
arrLoc = ii + (i * clk[clkCnt]);
if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
}else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
}else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
}else{ //error no peak detected
errCnt++;
}
}
//if we found no errors then we can stop here and a low clock (common clocks)
// this is correct one - return this clock
if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
if(errCnt==0 && clkCnt<7) {
if (!clockFnd) *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;
uint8_t best=0;
for (iii=1; iii<clkEnd; ++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 (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d",clk[iii],bestErr[iii],clk[best],bestStart[best]);
}
if (!clockFnd) *clock = clk[best];
return bestStart[best];
}
int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low, bool *strong) {
//find shortest transition from high to low
*strong = false;
size_t i = 0;
size_t transition1 = 0;
int lowestTransition = 255;
bool lastWasHigh = false;
size_t transitionSampleCount = 0;
//find first valid beginning of a high or low wave
while ((dest[i] >= peak || dest[i] <= low) && (i < size))
++i;
while ((dest[i] < peak && dest[i] > low) && (i < size))
++i;
lastWasHigh = (dest[i] >= peak);
if (i==size) return 0;
transition1 = i;
for (;i < size; i++) {
if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
lastWasHigh = (dest[i] >= peak);
if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
transition1 = i;
} else if (dest[i] < peak && dest[i] > low) {
transitionSampleCount++;
}
}
if (lowestTransition == 255) lowestTransition = 0;
if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
// if less than 10% of the samples were not peaks (or 90% were peaks) then we have a strong wave
if (transitionSampleCount / size < 10) {
*strong = true;
lowestTransition = getClosestClock(lowestTransition);
}
return lowestTransition;
}
//by marshmellow
//detect nrz clock by reading #peaks vs no peaks(or errors)
int DetectNRZClock(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
size_t i=0;
uint8_t clk[]={8,16,32,40,50,64,100,128,255};
size_t loopCnt = 4096; //don't need to loop through entire array...
if (size == 0) return 0;
if (size<loopCnt) loopCnt = size-20;
//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;
if (getHiLo(dest, loopCnt, &peak, &low, 90, 90) < 1) return 0;
bool strong = false;
int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low, &strong);
if (strong) return lowestTransition;
size_t ii;
uint8_t clkCnt;
uint8_t tol = 0;
uint16_t smplCnt = 0;
int16_t peakcnt = 0;
int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
uint16_t minPeak = 255;
bool firstpeak = true;
//test for large clipped waves - ignore first peak
for (i=0; i<loopCnt; i++) {
if (dest[i] >= peak || dest[i] <= low) {
if (firstpeak) continue;
smplCnt++;
} else {
firstpeak = false;
if (smplCnt > 0) {
if (minPeak > smplCnt && smplCnt > 7) minPeak = smplCnt;
peakcnt++;
if (g_debugMode == 2) prnt("DEBUG NRZ: minPeak: %d, smplCnt: %d, peakcnt: %d",minPeak,smplCnt,peakcnt);
smplCnt = 0;
}
}
}
if (minPeak < 8) return 0;
bool errBitHigh = 0;
bool bitHigh = 0;
uint8_t ignoreCnt = 0;
uint8_t ignoreWindow = 4;
bool lastPeakHigh = 0;
int lastBit = 0;
size_t bestStart[]={0,0,0,0,0,0,0,0,0};
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 smallest peak
if (clk[clkCnt] < minPeak - (clk[clkCnt]/4)) continue;
//try lining up the peaks by moving starting point (try first 256)
for (ii=20; ii < loopCnt; ++ii) {
if ((dest[ii] >= peak) || (dest[ii] <= low)) {
peakcnt = 0;
bitHigh = false;
ignoreCnt = 0;
lastBit = ii-clk[clkCnt];
//loop through to see if this start location works
for (i = ii; i < size-20; ++i) {
//if we are at a clock bit
if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
//test high/low
if (dest[i] >= peak || dest[i] <= low) {
//if same peak don't count it
if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
peakcnt++;
}
lastPeakHigh = (dest[i] >= peak);
bitHigh = true;
errBitHigh = false;
ignoreCnt = ignoreWindow;
lastBit += clk[clkCnt];
} else if (i == lastBit + clk[clkCnt] + tol) {
lastBit += clk[clkCnt];
}
//else if not a clock bit and no peaks
} else if (dest[i] < peak && dest[i] > low) {
if (ignoreCnt==0) {
bitHigh=false;
if (errBitHigh==true) peakcnt--;
errBitHigh=false;
} else {
ignoreCnt--;
}
// else if not a clock bit but we have a peak
} else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
//error bar found no clock...
errBitHigh=true;
}
}
if(peakcnt>peaksdet[clkCnt]) {
bestStart[clkCnt]=ii;
peaksdet[clkCnt]=peakcnt;
}
}
}
}
int iii=7;
uint8_t best=0;
for (iii=7; iii > 0; iii--) {
if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
best = iii;
}
} else if (peaksdet[iii] > peaksdet[best]) {
best = iii;
}
if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, minPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],minPeak, clk[best], lowestTransition);
}
*clockStartIdx = bestStart[best];
return clk[best];
}
//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 fskAdj) {
uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint8_t fcLensFnd = 0;
uint8_t lastFCcnt = 0;
uint8_t fcCounter = 0;
size_t i;
if (size < 180) return 0;
// prime i to first up transition
for (i = 160; i < size-20; i++)
if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
break;
for (; i < size-20; i++){
if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
// new up transition
fcCounter++;
if (fskAdj){
//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 fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
if ((fcCounter==9) || fcCounter==4) fcCounter++;
// save last field clock count (fc/xx)
lastFCcnt = fcCounter;
}
// find which fcLens to save it to:
for (int ii=0; ii<15; ii++){
if (fcLens[ii]==fcCounter){
fcCnts[ii]++;
fcCounter=0;
break;
}
}
if (fcCounter>0 && fcLensFnd<15){
//add new fc length
fcCnts[fcLensFnd]++;
fcLens[fcLensFnd++]=fcCounter;
}
fcCounter=0;
} else {
// count sample
fcCounter++;
}
}
uint8_t best1=14, best2=14, best3=14;
uint16_t maxCnt1=0;
// go through fclens and find which ones are bigest 2
for (i=0; i<15; 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;
}
if (g_debugMode==2) prnt("DEBUG countfc: FC %u, Cnt %u, best fc: %u, best2 fc: %u",fcLens[i],fcCnts[i],fcLens[best1],fcLens[best2]);
if (fcLens[i]==0) break;
}
if (fcLens[best1]==0) return 0;
uint8_t fcH=0, fcL=0;
if (fcLens[best1]>fcLens[best2]){
fcH=fcLens[best1];
fcL=fcLens[best2];
} else{
fcH=fcLens[best2];
fcL=fcLens[best1];
}
if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
if (g_debugMode==2) prnt("DEBUG countfc: fc is too large: %u > %u. Not psk or fsk",(size-180)/fcH/3,fcCnts[best1]+fcCnts[best2]);
return 0; //lots of waves not psk or fsk
}
// TODO: take top 3 answers and compare to known Field clocks to get top 2
uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
if (fskAdj) return fcs;
return (uint16_t)fcLens[best2] << 8 | fcLens[best1];
}
//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, size_t *firstPhaseShift, uint8_t *curPhase, uint8_t *fc) {
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+3<loopCnt) loopCnt = size-20;
uint16_t fcs = countFC(dest, size, 0);
*fc = fcs & 0xFF;
if (g_debugMode==2) prnt("DEBUG PSK: FC: %d, FC2: %d",*fc, fcs>>8);
if ((fcs>>8) == 10 && *fc == 8) return 0;
if (*fc!=2 && *fc!=4 && *fc!=8) return 0;
//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, tol=1;
uint16_t peakcnt=0, errCnt=0, waveLenCnt=0, fullWaveLen=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};
//find start of modulating data in trace
i = findModStart(dest, size, *fc);
firstFullWave = pskFindFirstPhaseShift(dest, size, curPhase, i, *fc, &fullWaveLen);
if (firstFullWave == 0) {
// no phase shift detected - could be all 1's or 0's - doesn't matter where we start
// so skip a little to ensure we are past any Start Signal
firstFullWave = 160;
fullWaveLen = 0;
}
*firstPhaseShift = firstFullWave;
if (g_debugMode ==2) prnt("DEBUG PSK: 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--) {
tol = *fc/2;
lastClkBit = firstFullWave; //set end of wave as clock align
waveStart = 0;
errCnt=0;
peakcnt=0;
if (g_debugMode == 2) prnt("DEBUG PSK: 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
if (g_debugMode == 2) prnt("DEBUG PSK: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,i+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;
}
if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
}
return clk[best];
}
//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, int *firstClockEdge) {
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;
uint16_t fcCounter = 0;
uint16_t rfCounter = 0;
uint8_t firstBitFnd = 0;
size_t i;
if (size == 0) return 0;
uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(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 peak / up transition
for (i = 160; i < size-20; i++)
if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
break;
for (; i < size-20; i++){
fcCounter++;
rfCounter++;
if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
continue;
// else new peak
// if we got less than the small fc + tolerance then set it to the small fc
// if it is inbetween set it to the last counter
if (fcCounter < fcHigh && fcCounter > fcLow)
fcCounter = lastFCcnt;
else 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-4) && rfLens[ii] <= (rfCounter+4)){
rfCnts[ii]++;
rfCounter = 0;
break;
}
}
if (rfCounter > 0 && rfLensFnd < 15){
//PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
rfCnts[rfLensFnd]++;
rfLens[rfLensFnd++] = rfCounter;
}
} else {
*firstClockEdge = i;
firstBitFnd++;
}
rfCounter=0;
lastFCcnt=fcCounter;
}
fcCounter=0;
}
uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
for (i=0; i<15; 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;
}
if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[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;
if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 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
// test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
int ii=7;
for (; ii>=2; 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){
if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
break;
}
}
}
}
if (ii<2) return 0; // oops we went too far
return clk[ii];
}
//**********************************************************************************************
//--------------------Modulation Demods &/or Decoding Section-----------------------------------
//**********************************************************************************************
// look for Sequence Terminator - should be pulses of clk*(1 or 2), clk*2, clk*(1.5 or 2), by idx we mean graph position index...
bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, size_t *i) {
if (buffSize < *i+4) return false;
for (; *i < buffSize - 4; *i+=1) {
*stStartIdx += lowToLowWaveLen[*i]; //caution part of this wave may be data and part may be ST.... to be accounted for in main function for now...
if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
if (lowToLowWaveLen[*i+1] >= clk*2-tol && lowToLowWaveLen[*i+1] <= clk*2+tol && highToLowWaveLen[*i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
if (lowToLowWaveLen[*i+2] >= (clk*3)/2-tol && lowToLowWaveLen[*i+2] <= clk*2+tol && highToLowWaveLen[*i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
*stStopLoc = *i + 3;
return true;
}
}
}
}
}
return false;
}
//by marshmellow
//attempt to identify a Sequence Terminator in ASK modulated raw wave
bool DetectST(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
size_t bufsize = *size;
//need to loop through all samples and identify our clock, look for the ST pattern
int clk = 0;
int tol = 0;
int j=0, high, low, skip=0, start=0, end=0, minClk=255;
size_t i = 0;
//probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
int tmpbuff[bufsize / LOWEST_DEFAULT_CLOCK]; // low to low wave count //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
int waveLen[bufsize / LOWEST_DEFAULT_CLOCK]; // high to low wave count //if clock is larger then we waste memory in array size that is not needed...
//size_t testsize = (bufsize < 512) ? bufsize : 512;
int phaseoff = 0;
high = low = 128;
memset(tmpbuff, 0, sizeof(tmpbuff));
memset(waveLen, 0, sizeof(waveLen));
if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
// set clock - might be able to get this externally and remove this work...
clk = getClosestClock(minClk);
// clock not found - ERROR
if (clk == 0) {
if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
return false;
}
*foundclock = clk;
tol = clk/8;
if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
// first ST not found - ERROR
if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
return false;
} else {
if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
}
if (waveLen[i+2] > clk*1+tol)
phaseoff = 0;
else
phaseoff = clk/2;
// skip over the remainder of ST
skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
// now do it again to find the end
int dummy1 = 0;
end = skip;
i+=3;
if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
//didn't find second ST - ERROR
if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
return false;
}
end -= phaseoff;
if (g_debugMode==2) prnt("DEBUG STT: start of data: %d end of data: %d, datalen: %d, clk: %d, bits: %d, phaseoff: %d", skip, end, end-skip, clk, (end-skip)/clk, phaseoff);
//now begin to trim out ST so we can use normal demod cmds
start = skip;
size_t datalen = end - start;
// check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
if ( clk - (datalen % clk) <= clk/8) {
// padd the amount off - could be problematic... but shouldn't happen often
datalen += clk - (datalen % clk);
} else if ( (datalen % clk) <= clk/8 ) {
// padd the amount off - could be problematic... but shouldn't happen often
datalen -= datalen % clk;
} else {
if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
return false;
}
// if datalen is less than one t55xx block - ERROR
if (datalen/clk < 8*4) {
if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
return false;
}
size_t dataloc = start;
if (buffer[dataloc-(clk*4)-(clk/4)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
//we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
for ( i=0; i <= (clk/4); ++i ) {
if ( buffer[dataloc - (clk*4) - i] <= low ) {
dataloc -= i;
break;
}
}
}
size_t newloc = 0;
i=0;
if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
bool firstrun = true;
// warning - overwriting buffer given with raw wave data with ST removed...
while ( dataloc < bufsize-(clk/2) ) {
//compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+clk/4]<high && buffer[dataloc+clk/4]>low) {
for(i=0; i < clk/2-tol; ++i) {
buffer[dataloc+i] = high+5;
}
} //test for small spike outlier (high between two lows) in the case of very strong waves
if (buffer[dataloc] > low && buffer[dataloc+clk/4] <= low) {
for(i=0; i < clk/4; ++i) {
buffer[dataloc+i] = buffer[dataloc+clk/4];
}
}
if (firstrun) {
*stend = dataloc;
*ststart = dataloc-(clk*4);
firstrun=false;
}
for (i=0; i<datalen; ++i) {
if (i+newloc < bufsize) {
if (i+newloc < dataloc)
buffer[i+newloc] = buffer[dataloc];
dataloc++;
}
}
newloc += i;
//skip next ST - we just assume it will be there from now on...
if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
dataloc += clk*4;
}
*size = newloc;
return true;
}
//by marshmellow
//take 11 10 01 11 00 and make 01100 ... miller decoding
//check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
//decodes miller encoded binary
//NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
if (*size < 16) return -1;
uint16_t MaxBits = 512, errCnt = 0;
size_t i, bitCnt=0;
uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
uint8_t halfClkErr = 0;
//find alignment, needs 4 1s or 0s to properly align
for (i=1; i < *size-1; i++) {
alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
curBit = BitStream[i];
if (alignCnt == 4) break;
}
// for now error if alignment not found. later add option to run it with multiple offsets...
if (alignCnt != 4) {
if (g_debugMode) prnt("ERROR MillerDecode: alignment not found so either your bitstream is not miller or your data does not have a 101 in it");
return -1;
}
alignedIdx = (i-1) % 2;
for (i=alignedIdx; i < *size-3; i+=2) {
halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
errCnt++;
BitStream[bitCnt++] = 7;
continue;
}
BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
if (bitCnt > MaxBits) break;
}
*size = bitCnt;
return errCnt;
}
//by marshmellow
//take 01 or 10 = 1 and 11 or 00 = 0
//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int *offset, int invert) {
uint16_t bitnum = 0;
uint16_t errCnt = 0;
size_t i = *offset;
uint16_t MaxBits=512;
//if not enough samples - error
if (*size < 51) return -1;
//check for phase change faults - skip one sample if faulty
uint8_t offsetA = 1, offsetB = 1;
for (; i<48; i+=2){
if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
}
if (!offsetA && offsetB) *offset+=1;
for (i=*offset; i<*size-3; i+=2){
//check for phase error
if (BitStream[i+1]==BitStream[i+2]) {
BitStream[bitnum++]=7;
errCnt++;
}
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++]=7;
errCnt++;
}
if(bitnum>MaxBits) break;
}
*size=bitnum;
return errCnt;
}
//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, uint8_t invert, uint8_t *alignPos) {
uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
size_t i, ii;
uint16_t bestErr = 1000, bestRun = 0;
if (*size < 16) return -1;
//find correct start position [alignment]
for (ii=0;ii<2;++ii){
for (i=ii; i<*size-3; i+=2)
if (BitStream[i]==BitStream[i+1])
errCnt++;
if (bestErr>errCnt){
bestErr=errCnt;
bestRun=ii;
}
errCnt=0;
}
*alignPos=bestRun;
//decode
for (i=bestRun; i < *size-3; i+=2){
if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
BitStream[bitnum++]=invert;
} else if((BitStream[i] == 0) && BitStream[i+1] == 1){
BitStream[bitnum++]=invert^1;
} else {
BitStream[bitnum++]=7;
}
if(bitnum>MaxBits) break;
}
*size=bitnum;
return bestErr;
}
//by marshmellow
//demodulates strong heavily clipped samples
int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
{
*startIdx=0;
size_t bitCnt=0, smplCnt=1, errCnt=0;
bool waveHigh = (BinStream[0] >= high);
for (size_t i=1; i < *size; i++){
if (BinStream[i] >= high && waveHigh){
smplCnt++;
} else if (BinStream[i] <= low && !waveHigh){
smplCnt++;
} else { //transition
if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
if (smplCnt > clk-(clk/4)-1) { //full clock
if (smplCnt > clk + (clk/4)+1) { //too many samples
errCnt++;
if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
BinStream[bitCnt++] = 7;
} else if (waveHigh) {
BinStream[bitCnt++] = invert;
BinStream[bitCnt++] = invert;
} else if (!waveHigh) {
BinStream[bitCnt++] = invert ^ 1;
BinStream[bitCnt++] = invert ^ 1;
}
if (*startIdx==0) *startIdx = i-clk;
waveHigh = !waveHigh;
smplCnt = 0;
} else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
if (waveHigh) {
BinStream[bitCnt++] = invert;
} else if (!waveHigh) {
BinStream[bitCnt++] = invert ^ 1;
}
if (*startIdx==0) *startIdx = i-(clk/2);
waveHigh = !waveHigh;
smplCnt = 0;
} else {
smplCnt++;
//transition bit oops
}
} else { //haven't hit new high or new low yet
smplCnt++;
}
}
}
*size = bitCnt;
return errCnt;
}
//by marshmellow
//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
if (*size==0) return -1;
int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
if (*clk==0 || start < 0) return -3;
if (*invert != 1) *invert = 0;
if (amp==1) askAmp(BinStream, *size);
if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
//start pos from detect ask clock is 1/2 clock offset
// NOTE: can be negative (demod assumes rest of wave was there)
*startIdx = start - (*clk/2);
uint8_t initLoopMax = 255;
if (initLoopMax > *size) initLoopMax = *size;
// Detect high and lows
//25% clip in case highs and lows aren't clipped [marshmellow]
int high, low;
if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
return -2; //just noise
size_t errCnt = 0;
// if clean clipped waves detected run alternate demod
if (DetectCleanAskWave(BinStream, *size, high, low)) {
if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
if (askType) { //askman
uint8_t alignPos = 0;
errCnt = manrawdecode(BinStream, size, 0, &alignPos);
*startIdx += *clk/2 * alignPos;
if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
return errCnt;
} else { //askraw
return errCnt;
}
}
if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
int lastBit; //set first clock check - can go negative
size_t i, bitnum = 0; //output counter
uint8_t midBit = 0;
uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
if (*clk <= 32) tol = 1; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
size_t MaxBits = 3072; //max bits to collect
lastBit = start - *clk;
for (i = start; i < *size; ++i) {
if (i-lastBit >= *clk-tol){
if (BinStream[i] >= high) {
BinStream[bitnum++] = *invert;
} else if (BinStream[i] <= low) {
BinStream[bitnum++] = *invert ^ 1;
} else if (i-lastBit >= *clk+tol) {
if (bitnum > 0) {
if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
BinStream[bitnum++]=7;
errCnt++;
}
} else { //in tolerance - looking for peak
continue;
}
midBit = 0;
lastBit += *clk;
} else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
if (BinStream[i] >= high) {
BinStream[bitnum++] = *invert;
} else if (BinStream[i] <= low) {
BinStream[bitnum++] = *invert ^ 1;
} else if (i-lastBit >= *clk/2+tol) {
BinStream[bitnum] = BinStream[bitnum-1];
bitnum++;
} else { //in tolerance - looking for peak
continue;
}
midBit = 1;
}
if (bitnum >= MaxBits) break;
}
*size = bitnum;
return errCnt;
}
int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
int start = 0;
return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
}
// by marshmellow - demodulate NRZ wave - requires a read with strong signal
// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
if (justNoise(dest, *size)) return -1;
size_t clkStartIdx = 0;
*clk = DetectNRZClock(dest, *size, *clk, &clkStartIdx);
if (*clk==0) return -2;
size_t i, gLen = 4096;
if (gLen>*size) gLen = *size-20;
int high, low;
if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
uint8_t bit=0;
//convert wave samples to 1's and 0's
for(i=20; i < *size-20; i++){
if (dest[i] >= high) bit = 1;
if (dest[i] <= low) bit = 0;
dest[i] = bit;
}
//now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
size_t lastBit = 0;
size_t numBits = 0;
for(i=21; i < *size-20; i++) {
//if transition detected or large number of same bits - store the passed bits
if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
numBits += (i - lastBit + (*clk/4)) / *clk;
if (lastBit == 0) {
*startIdx = i - (numBits * *clk);
if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
}
lastBit = i-1;
}
}
*size = numBits;
return 0;
}
//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
size_t last_transition = 0;
size_t idx = 1;
if (fchigh==0) fchigh=10;
if (fclow==0) fclow=8;
//set the threshold close to 0 (graph) or 128 std to avoid static
size_t preLastSample = 0;
size_t LastSample = 0;
size_t currSample = 0;
if ( size < 1024 ) return 0; // not enough samples
//find start of modulating data in trace
idx = findModStart(dest, size, fchigh);
// Need to threshold first sample
if(dest[idx] < FSK_PSK_THRESHOLD) dest[0] = 0;
else dest[0] = 1;
last_transition = idx;
idx++;
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 anywhere
// between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
// (could also be fc/5 && fc/7 for fsk1 = 4-9)
for(; idx < size; idx++) {
// threshold current value
if (dest[idx] < FSK_PSK_THRESHOLD) dest[idx] = 0;
else dest[idx] = 1;
// Check for 0->1 transition
if (dest[idx-1] < dest[idx]) {
preLastSample = LastSample;
LastSample = currSample;
currSample = idx-last_transition;
if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
//do nothing with extra garbage
} else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
//correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
dest[numBits-1]=1;
}
dest[numBits++]=1;
if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
} else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
//do nothing with beginning garbage and reset.. should be rare..
numBits = 0;
} else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
dest[numBits++]=1;
if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
} else { //9+ = 10 sample waves (or 6+ = 7)
dest[numBits++]=0;
if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
}
last_transition = idx;
}
}
return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
}
//translate 11111100000 to 10
//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
uint8_t lastval=dest[0];
size_t idx=0;
size_t numBits=0;
uint32_t n=1;
for( idx=1; idx < size; idx++) {
n++;
if (dest[idx]==lastval) continue; //skip until we hit a transition
//find out how many bits (n) we collected (use 1/2 clk tolerance)
//if lastval was 1, we have a 1->0 crossing
if (dest[idx-1]==1) {
n = (n * fclow + rfLen/2) / rfLen;
} else {// 0->1 crossing
n = (n * fchigh + rfLen/2) / rfLen;
}
if (n == 0) n = 1;
//first transition - save startidx
if (numBits == 0) {
if (lastval == 1) { //high to low
*startIdx += (fclow * idx) - (n*rfLen);
if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
} else {
*startIdx += (fchigh * idx) - (n*rfLen);
if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
}
}
//add to our destination the bits we collected
memset(dest+numBits, dest[idx-1]^invert , n);
numBits += n;
n=0;
lastval=dest[idx];
}//end for
// if valid extra bits at the end were all the same frequency - add them in
if (n > rfLen/fchigh) {
if (dest[idx-2]==1) {
n = (n * fclow + rfLen/2) / rfLen;
} else {
n = (n * fchigh + rfLen/2) / rfLen;
}
memset(dest+numBits, dest[idx-1]^invert , n);
numBits += n;
}
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, int *startIdx) {
if (justNoise(dest, size)) return 0;
// FSK demodulator
size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
return size;
}
// 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 (BitStream[i]==7){
//ignore errors
} else 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) {
uint8_t phase=0;
for (size_t i=0; i<size; i++){
if (BitStream[i]==1){
phase ^=1;
}
BitStream[i]=phase;
}
return;
}
//by marshmellow - demodulate PSK1 wave
//uses wave lengths (# Samples)
int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
if (*size < 170) return -1;
uint8_t curPhase = *invert;
uint8_t fc=0;
size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
uint16_t fullWaveLen=0, waveLenCnt=0, avgWaveVal;
uint16_t errCnt=0, errCnt2=0;
*clock = DetectPSKClock(dest, *size, *clock, &firstFullWave, &curPhase, &fc);
if (*clock <= 0) return -1;
//if clock detect found firstfullwave...
uint16_t tol = fc/2;
if (firstFullWave == 0) {
//find start of modulating data in trace
i = findModStart(dest, *size, fc);
//find first phase shift
firstFullWave = pskFindFirstPhaseShift(dest, *size, &curPhase, i, fc, &fullWaveLen);
if (firstFullWave == 0) {
// no phase shift detected - could be all 1's or 0's - doesn't matter where we start
// so skip a little to ensure we are past any Start Signal
firstFullWave = 160;
memset(dest, curPhase, firstFullWave / *clock);
} else {
memset(dest, curPhase^1, firstFullWave / *clock);
}
} else {
memset(dest, curPhase^1, firstFullWave / *clock);
}
//advance bits
numBits += (firstFullWave / *clock);
*startIdx = firstFullWave - (*clock * numBits)+2;
//set start of wave as clock align
lastClkBit = firstFullWave;
if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
waveStart = 0;
dest[numBits++] = curPhase; //set first read bit
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;
if (waveLenCnt > fc) {
//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;
lastClkBit += *clock;
} else if (i < lastClkBit+10+fc) {
//noise after a phase shift - ignore
} else { //phase shift before supposed to based on clock
errCnt++;
dest[numBits++] = 7;
}
} else if (i+1 > lastClkBit + *clock + tol + fc) {
lastClkBit += *clock; //no phase shift but clock bit
dest[numBits++] = curPhase;
} else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
errCnt2++;
if(errCnt2 > 101) return errCnt2;
avgWaveVal += dest[i+1];
continue;
}
avgWaveVal = 0;
waveStart = i+1;
}
}
avgWaveVal += dest[i+1];
}
*size = numBits;
return errCnt;
}
int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
int startIdx = 0;
return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
}
//**********************************************************************************************
//-----------------Tag format detection section-------------------------------------------------
//**********************************************************************************************
// by marshmellow
// FSK Demod then try to locate an AWID ID
int AWIDdemodFSK(uint8_t *dest, size_t *size, int *waveStartIdx) {
//make sure buffer has enough data
if (*size < 96*50) return -1;
// FSK demodulator
*size = fskdemod(dest, *size, 50, 1, 10, 8, waveStartIdx); // 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
//takes 1s and 0s and searches for EM410x format - output EM ID
uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
{
//sanity checks
if (*size < 64) return 0;
if (BitStream[1]>1) return 0; //allow only 1s and 0s
// 111111111 bit pattern represent start of frame
// include 0 in front to help get start pos
uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
uint8_t errChk = 0;
uint8_t FmtLen = 10; // sets of 4 bits = end data
*startIdx = 0;
errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
//skip last 4bit parity row for simplicity
*size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
if (*size == 40) { // std em410x format
*hi = 0;
*lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
} else if (*size == 88) { // long em format
*hi = (bytebits_to_byte(BitStream, 24));
*lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
} else {
if (g_debugMode) prnt("Error removing parity: %u", *size);
return 0;
}
return 1;
}
// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
// BitStream must contain previously askrawdemod and biphasedemoded data
int FDXBdemodBI(uint8_t *dest, size_t *size) {
//make sure buffer has enough data
if (*size < 128) return -1;
size_t startIdx = 0;
uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -2; //preamble not found
if (*size != 128) return -3; //wrong size for fdxb
//return start position
return (int)startIdx;
}
// by marshmellow
// demod gProxIIDemod
// error returns as -x
// success returns start position in BitStream
// BitStream must contain previously askrawdemod and biphasedemoded data
int gProxII_Demod(uint8_t BitStream[], size_t *size) {
size_t startIdx=0;
uint8_t preamble[] = {1,1,1,1,1,0};
uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -3; //preamble not found
if (*size != 96) return -2; //should have found 96 bits
//check first 6 spacer bits to verify format
if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
//confirmed proper separator bits found
//return start position
return (int) startIdx;
}
return -5; //spacer bits not found - not a valid gproxII
}
// 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, int *waveStartIdx) {
size_t numStart=0, size2=*size, startIdx=0;
// FSK demodulator fsk2a so invert and fc/10/8
*size = fskdemod(dest, size2, 50, 1, 10, 8, waveStartIdx);
if (*size < 96*2) 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;
}
int IOdemodFSK(uint8_t *dest, size_t size, int *waveStartIdx) {
//make sure buffer has data
if (size < 66*64) return -2;
// FSK demodulator RF/64, fsk2a so invert, and fc/10/8
size = fskdemod(dest, size, 64, 1, 10, 8, waveStartIdx);
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;
}
// redesigned by marshmellow adjusted from existing decode functions
// indala id decoding
int indala64decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
//standard 64 bit indala formats including 26 bit 40134 format
uint8_t preamble64[] = {1,0,1,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 1};
uint8_t preamble64_i[] = {0,1,0,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 0};
size_t startidx = 0;
size_t found_size = *size;
bool found = preambleSearch(bitStream, preamble64, sizeof(preamble64), &found_size, &startidx);
if (!found) {
found = preambleSearch(bitStream, preamble64_i, sizeof(preamble64_i), &found_size, &startidx);
if (!found) return -1;
*invert ^= 1;
}
if (found_size != 64) return -2;
if (*invert==1)
for (size_t i = startidx; i < found_size + startidx; i++)
bitStream[i] ^= 1;
// note: don't change *size until we are sure we got it...
*size = found_size;
return (int) startidx;
}
int indala224decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
//large 224 bit indala formats (different preamble too...)
uint8_t preamble224[] = {1,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,1};
uint8_t preamble224_i[] = {0,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,0};
size_t startidx = 0;
size_t found_size = *size;
bool found = preambleSearch(bitStream, preamble224, sizeof(preamble224), &found_size, &startidx);
if (!found) {
found = preambleSearch(bitStream, preamble224_i, sizeof(preamble224_i), &found_size, &startidx);
if (!found) return -1;
*invert ^= 1;
}
if (found_size != 224) return -2;
if (*invert==1 && startidx > 0)
for (size_t i = startidx-1; i < found_size + startidx + 2; i++)
bitStream[i] ^= 1;
// 224 formats are typically PSK2 (afaik 2017 Marshmellow)
// note loses 1 bit at beginning of transformation...
// don't need to verify array is big enough as to get here there has to be a full preamble after all of our data
psk1TOpsk2(bitStream + (startidx-1), found_size+2);
startidx++;
*size = found_size;
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, int *waveStartIdx) {
size_t numStart=0, size2=*size, startIdx=0;
// FSK demodulator
*size = fskdemod(dest, size2,50,1,10,8,waveStartIdx); //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;
}
// find presco preamble 0x10D in already demoded data
int PrescoDemod(uint8_t *dest, size_t *size) {
//make sure buffer has data
if (*size < 64*2) return -2;
size_t startIdx = 0;
uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -4; //preamble not found
//return start position
return (int) startIdx;
}
// by marshmellow
// FSK Demod then try to locate a Farpointe Data (pyramid) ID
int PyramiddemodFSK(uint8_t *dest, size_t *size, int *waveStartIdx) {
//make sure buffer has data
if (*size < 128*50) return -5;
// FSK demodulator
*size = fskdemod(dest, *size, 50, 1, 10, 8, waveStartIdx); // 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;
}
// by marshmellow
// find viking preamble 0xF200 in already demoded data
int VikingDemod_AM(uint8_t *dest, size_t *size) {
//make sure buffer has data
if (*size < 64*2) return -2;
size_t startIdx = 0;
uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
if (errChk == 0) return -4; //preamble not found
uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
if ( checkCalc != 0xA8 ) return -5;
if (*size != 64) return -6;
//return start position
return (int) startIdx;
}
// by iceman
// find Visa2000 preamble in already demoded data
int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
if (*size < 96) return -1; //make sure buffer has data
size_t startIdx = 0;
uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0};
if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
return -2; //preamble not found
if (*size != 96) return -3; //wrong demoded size
//return start position
return (int)startIdx;
}