// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
-// Low frequency demod/decode commands
+// 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 currenlty safe for
+// device side use currently. (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 <stdlib.h>
+#include <string.h> // for memset, memcmp and size_t
#include "lfdemod.h"
-#include <string.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"
#define prnt dummy
#endif
-uint8_t justNoise(uint8_t *BitStream, size_t size)
-{
- static const uint8_t THRESHOLD = 123;
+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] < THRESHOLD;
+ 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)
-{
+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
if (BitStream[i] > *high) *high = BitStream[i];
if (BitStream[i] < *low) *low = BitStream[i];
}
- if (*high < 123) return -1; // just noise
+ 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
-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);
- }
- if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
- return (ans == pType);
+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),
-// 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)
-{
+// 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 j = 0, bitCnt = 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[j++] = (BitStream[startIdx+word+bit]);
+ BitStream[bitCnt++] = (BitStream[startIdx+word+bit]);
}
- if (word+pLen >= bLen) break;
+ if (word+pLen > bLen) break;
- j--; // overwrite parity with next data
+ bitCnt--; // overwrite parity with next data
// if parity fails then return 0
switch (pType) {
- case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
- case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
+ 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
}
- bitCnt+=(pLen-1);
parityWd = 0;
}
// if we got here then all the parities passed
- //return ID start index and size
+ //return size
return bitCnt;
}
// 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)
-{
+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) {
return bitCnt;
}
-uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
-{
+uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) {
uint32_t num = 0;
for(int i = 0 ; i < numbits ; i++)
{
}
//least significant bit first
-uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
-{
+uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) {
uint32_t num = 0;
for(int i = 0 ; i < numbits ; i++)
{
return num;
}
-//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)
-{
+// 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 0;
+ if ( *size <= pLen ) return false;
- uint8_t foundCnt=0;
- for (int idx=0; idx < *size - pLen; idx++){
- if (memcmp(BitStream+idx, preamble, pLen) == 0){
+ 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 (foundCnt == 1) {
+ if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
*startIdx = idx;
- }
- if (foundCnt == 2){
+ if (findone) return true;
+ } else if (foundCnt == 2) {
*size = idx - *startIdx;
- return 1;
+ return true;
}
}
}
- return 0;
+ return false;
}
-// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
-// does not look for a repeating preamble
-// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
-// leave it generic so it could be reused later...
-bool onePreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t size, size_t *startIdx) {
- // Sanity check. If preamble length is bigger than bitstream length.
- if ( size <= pLen ) return false;
- for (size_t idx = 0; idx < size - pLen; idx++) {
- if (memcmp(BitStream+idx, preamble, pLen) == 0) {
- if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
- *startIdx = idx;
- 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 threshold_value, uint8_t expWaveSize) {
+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++] >= threshold_value;
+ bool isAboveThreshold = dest[i++] >= FSK_PSK_THRESHOLD;
for (; i < size-20; i++ ) {
- if(dest[i] < threshold_value && isAboveThreshold) {
+ if(dest[i] < FSK_PSK_THRESHOLD && isAboveThreshold) {
thresholdCnt++;
if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
isAboveThreshold = false;
waveSizeCnt = 0;
- } else if (dest[i] >= threshold_value && !isAboveThreshold) {
+ } else if (dest[i] >= FSK_PSK_THRESHOLD && !isAboveThreshold) {
thresholdCnt++;
if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
isAboveThreshold = true;
return i;
}
-//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)
-{
- //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
- uint32_t i = 0;
- if (BitStream[1]>1) return 0; //allow only 1s and 0s
+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];
- // 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};
- uint32_t idx = 0;
- uint32_t parityBits = 0;
- uint8_t errChk = 0;
- uint8_t FmtLen = 10;
- *startIdx = 0;
- errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
- if (errChk == 0 || *size < 64) return 0;
- if (*size > 64) FmtLen = 22;
- *startIdx += 1; //get rid of 0 from preamble
- idx = *startIdx + 9;
- for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
- parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
- //check even parity - quit if failed
- if (parityTest(parityBits, 5, 0) == 0) return 0;
- //set uint64 with ID from BitStream
- for (uint8_t ii=0; ii<4; ii++){
- *hi = (*hi << 1) | (*lo >> 63);
- *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
- }
- }
- if (errChk != 0) return 1;
- //skip last 5 bit parity test for simplicity.
- // *size = 64 | 128;
return 0;
}
-//by marshmellow
-//demodulates strong heavily clipped samples
-int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
-{
- size_t bitCnt=0, smplCnt=0, errCnt=0;
- uint8_t waveHigh = 0;
- for (size_t i=0; 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;
- }
- waveHigh ^= 1;
- smplCnt = 0;
- } else if (smplCnt > (clk/2) - (clk/4)-1) {
- if (waveHigh) {
- BinStream[bitCnt++] = invert;
- } else if (!waveHigh) {
- BinStream[bitCnt++] = invert ^ 1;
- }
- waveHigh ^= 1;
- smplCnt = 0;
- } else if (!bitCnt) {
- //first bit
- waveHigh = (BinStream[i] >= high);
- smplCnt = 1;
- } else {
- smplCnt++;
- //transition bit oops
- }
- } else { //haven't hit new high or new low yet
- smplCnt++;
- }
- }
- }
- *size = bitCnt;
- return errCnt;
+void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) {
+ while ((samples[*i] > low) && (*i < size))
+ *i+=1;
}
-//by marshmellow
-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;
+void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) {
+ while ((samples[*i] < high) && (*i < size))
+ *i+=1;
+}
- BitStream[i-1] = Last;
+// 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
}
- return;
-}
-
-//by marshmellow
-//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
-int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
-{
- 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);
- 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
+ // 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;
- 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);
- if (askType) //askman
- return manrawdecode(BinStream, size, 0);
- else //askraw
- return errCnt;
+ // 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;
+ }
}
- if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
+ return true;
+}
- 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;
+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...
- 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;
+ 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;
}
- midBit = 1;
+ waveStart = i+1;
+ avgWaveVal = 0;
}
- if (bitnum >= MaxBits) break;
+ avgWaveVal += samples[i+2];
}
- *size = bitnum;
- return errCnt;
+ return 0;
}
//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)
-{
- 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++;
+//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;
- if (bestErr>errCnt){
- bestErr=errCnt;
- bestRun=ii;
- }
- errCnt=0;
- }
- //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;
+ BitStream[i-1] = Last;
}
- *size=bitnum;
- return bestErr;
+ return;
}
uint32_t manchesterEncode2Bytes(uint16_t datain) {
//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;
+//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<(size*2); i++){
- BitStream[i] = BitStream[i+20000];
+ for (i=0; i<(size*2); i++){
+ BitStream[i] = BitStream[i+size];
}
return i;
}
-//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++;
- 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
-// 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;
+// 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++;
}
- return -5; //spacer bits not found - not a valid gproxII
+ if (!allArePeaks){
+ if (cntPeaks > 300) return true;
+ }
+ return allArePeaks;
}
-//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)
-{
- 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
- uint8_t threshold_value = 123;
- size_t preLastSample = 0;
- size_t LastSample = 0;
- size_t currSample = 0;
- if ( size < 1024 ) return 0; // not enough samples
+//**********************************************************************************************
+//-------------------Clock / Bitrate Detection Section------------------------------------------
+//**********************************************************************************************
- //find start of modulating data in trace
- idx = findModStart(dest, size, threshold_value, fchigh);
+// 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);
- // Need to threshold first sample
- if(dest[idx] < threshold_value) dest[0] = 0;
- else dest[0] = 1;
- 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-20; idx++) {
- // threshold current value
+ // loop through all samples
+ while (i < size) {
+ // measure from low to low
+ startwave = i;
- if (dest[idx] < threshold_value) dest[idx] = 0;
- else dest[idx] = 1;
+ 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;
+}
- // 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 (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
- dest[numBits-1]=1;
- }
- dest[numBits++]=1;
+// 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
- } 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;
- } else { //9+ = 10 sample waves (or 6+ = 7)
- dest[numBits++]=0;
+ //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
}
- last_transition = idx;
}
}
- return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
-}
+ 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;
-//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)
-{
- 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
- //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 (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 (n == 0) n = 1;
+ //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;
- //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;
+ 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;
+ }
}
- memset(dest+numBits, dest[idx-1]^invert , n);
- numBits += n;
}
- return numBits;
+ 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];
}
-//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, invert, fchigh, fclow);
- return size;
-}
+int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
+ //find shortest transition from high to low
+ size_t i = 0;
+ size_t transition1 = 0;
+ int lowestTransition = 255;
+ bool lastWasHigh = false;
-// 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;
+ //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);
- size_t numStart=0, size2=*size, startIdx=0;
- // FSK demodulator
- *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
- 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
+ if (i==size) return 0;
+ transition1 = i;
- 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
+ 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;
}
- *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;
+ if (lowestTransition == 255) lowestTransition = 0;
+ if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
+ return lowestTransition;
}
-// 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};
+//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;
- uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
- if (errChk == 0) return -3; //preamble not found
+ //get high and low peak
+ int peak, low;
+ if (getHiLo(dest, loopCnt, &peak, &low, 90, 90) < 1) return 0;
- 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;
+ int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
+ 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;
+ }
+ }
}
- return (int)startIdx;
+ 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];
}
-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
+//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;
- 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;
-}
+ // 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;
-// 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;
+ 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
- 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;
+ uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
+ if (fskAdj) return fcs;
+ return (uint16_t)fcLens[best2] << 8 | fcLens[best1];
}
-// 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;
+//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;
- 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;
-}
+ 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;
-// 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;
+ //if we already have a valid clock quit
+ size_t i=1;
+ for (; i < 8; ++i)
+ if (clk[i] == clock) return clock;
- size_t startIdx = 0;
- uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
+ size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
- uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
- if (errChk == 0) return -2; //preamble not found
- return (int)startIdx;
-}
+ 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};
-// 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;
+ //find start of modulating data in trace
+ i = findModStart(dest, size, *fc);
- if (justNoise(dest, *size)) return -2;
+ 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;
+ }
- // FSK demodulator
- *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
- if (*size < 96) return -3; //did we get a good demod?
+ *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);
- 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;
+ 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
-// FSK Demod then try to locate a Farpointe Data (pyramid) ID
-int PyramiddemodFSK(uint8_t *dest, size_t *size)
-{
- //make sure buffer has data
- if (*size < 128*50) return -5;
+//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;
- //test samples are not just noise
- if (justNoise(dest, *size)) return -1;
+ 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;
- // FSK demodulator
- *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
- if (*size < 128) return -2; //did we get a good demod?
+ 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
- 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;
+ return clk[ii];
}
-// 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;
+//**********************************************************************************************
+//--------------------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 allArePeaks;
+ return false;
}
-// 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, uint8_t high, uint8_t low)
-{
- uint8_t fndClk[] = {8,16,32,40,50,64,128};
- size_t startwave;
- size_t i = 100;
- size_t minClk = 255;
- // get to first full low to prime loop and skip incomplete first pulse
- while ((dest[i] < high) && (i < size))
- ++i;
- while ((dest[i] > low) && (i < size))
- ++i;
+//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));
- // loop through all samples
- while (i < size) {
- // measure from low to low
- while ((dest[i] > low) && (i < size))
- ++i;
- startwave= i;
- while ((dest[i] < high) && (i < size))
- ++i;
- while ((dest[i] > low) && (i < size))
- ++i;
- //get minimum measured distance
- if (i-startwave < minClk && i < size)
- minClk = i - startwave;
- }
- // set clock
- if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
- for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
- if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
- return fndClk[clkCnt];
+ 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;
}
- return 0;
-}
+ *foundclock = clk;
-// 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
+ 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
- //get high and low peak
- int peak, low;
- if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
+ // 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;
+ }
+ }
+ }
- //test for large clean peaks
- if (!clockFnd){
- if (DetectCleanAskWave(dest, size, peak, low)==1){
- int ans = DetectStrongAskClock(dest, size, peak, low);
- if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
- for (i=clkEnd-1; i>0; i--){
- if (clk[i] == ans) {
- *clock = ans;
- //clockFnd = i;
- return 0; // for strong waves i don't use the 'best start position' yet...
- //break; //clock found but continue to find best startpos [not yet]
- }
+ 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;
}
- 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;
+ *size = newloc;
+ return true;
+}
- if (clockFnd>0) {
- clkCnt = clockFnd;
- clkEnd = clockFnd+1;
+//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;
}
- else clkCnt=1;
+ *size = bitCnt;
+ return errCnt;
+}
- //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;
+//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 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;
+ 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;
+}
- 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;
- }
+//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;
}
- 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;
- }
+ *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 (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(bitnum>MaxBits) break;
}
- if (!clockFnd) *clock = clk[best];
- return bestStart[best];
+ *size=bitnum;
+ return bestErr;
}
//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)
+//demodulates strong heavily clipped samples
+int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
{
- 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-20;
-
- //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};
- fc = countFC(dest, size, 0);
- if (fc!=2 && fc!=4 && fc!=8) return -1;
- if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
-
- //find first full wave
- for (i=160; i<loopCnt; i++){
- if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
- if (waveStart == 0) {
- waveStart = i+1;
- //prnt("DEBUG: waveStart: %d",waveStart);
- } else {
- waveEnd = i+1;
- //prnt("DEBUG: waveEnd: %d",waveEnd);
- waveLenCnt = waveEnd-waveStart;
- if (waveLenCnt > fc){
- firstFullWave = waveStart;
- fullWaveLen=waveLenCnt;
- break;
- }
- waveStart=0;
- }
- }
- }
- 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--){
- 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
+ *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;
}
- waveStart=i+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++;
}
}
- 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];
+ *size = bitCnt;
+ return errCnt;
}
-int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
- //find shortest transition from high to low
- size_t i = 0;
- size_t transition1 = 0;
- int lowestTransition = 255;
- bool lastWasHigh = false;
+//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);
- //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);
+ //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
- if (i==size) return 0;
- transition1 = i;
+ 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");
- 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;
+ 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;
}
- if (lowestTransition == 255) lowestTransition = 0;
- if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
- return lowestTransition;
+ *size = bitnum;
+ return errCnt;
}
-//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 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, 75, 75) < 1) return 0;
+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);
+}
- int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
- 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 maxPeak = 255;
- bool firstpeak = false;
- //test for large clipped waves
- for (i=0; i<loopCnt; i++){
- if (dest[i] >= peak || dest[i] <= low){
- if (!firstpeak) continue;
- smplCnt++;
- } else {
- firstpeak=true;
- if (smplCnt > 6 ){
- if (maxPeak > smplCnt){
- maxPeak = smplCnt;
- //prnt("maxPk: %d",maxPeak);
- }
- peakcnt++;
- //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
- smplCnt=0;
+// 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;
}
}
- bool errBitHigh = 0;
- bool bitHigh = 0;
- uint8_t ignoreCnt = 0;
- uint8_t ignoreWindow = 4;
- bool lastPeakHigh = 0;
- int lastBit = 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] < maxPeak - (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]) {
- peaksdet[clkCnt]=peakcnt;
+ *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;
}
}
- 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;
+ 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);
}
- } else if (peaksdet[iii] > peaksdet[best]){
- best = iii;
}
- if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition);
+
+ //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;
+}
- return clk[best];
+//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)
-{
+void psk1TOpsk2(uint8_t *BitStream, size_t size) {
size_t i=1;
uint8_t lastBit=BitStream[0];
for (; i<size; i++){
// 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)
-{
+void psk2TOpsk1(uint8_t *BitStream, size_t size) {
uint8_t phase=0;
for (size_t i=0; i<size; i++){
if (BitStream[i]==1){
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)
- uint8_t preamble[] = {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 preamble_i[] = {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;
- if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
- // if didn't find preamble try again inverting
- if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
- *invert ^= 1;
- }
- if (*size != 64 && *size != 224) return -2;
- if (*invert==1)
- for (size_t i = startidx; i < *size; i++)
- bitStream[i] ^= 1;
-
- return (int) startidx;
-}
+//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;
-// 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){
- if (justNoise(dest, *size)) return -1;
- *clk = DetectNRZClock(dest, *size, *clk);
- 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 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;
- 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;
- lastBit = i-1;
+ *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);
}
- *size = numBits;
- return 0;
-}
-
-//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;
- 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 (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;
+ //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;
}
- if (rfCounter > 0 && rfLensFnd < 15){
- //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
- rfCnts[rfLensFnd]++;
- rfLens[rfLensFnd++] = rfCounter;
- }
- } else {
- firstBitFnd++;
+ avgWaveVal = 0;
+ waveStart = i+1;
}
- rfCounter=0;
- lastFCcnt=fcCounter;
}
- fcCounter=0;
+ avgWaveVal += dest[i+1];
}
- uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
+ *size = numBits;
+ return errCnt;
+}
- 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]);
+int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
+ int startIdx = 0;
+ return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
+}
- // 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;
- }
- }
- }
- }
+//**********************************************************************************************
+//-----------------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;
- if (ii<0) return 0; // oops we went too far
+ // 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?
- return clk[ii];
+ 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
-//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)
+//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)
{
- 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;
+ //sanity checks
+ if (*size < 64) return 0;
+ if (BitStream[1]>1) return 0; //allow only 1s and 0s
- // 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;
+ // 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;
+}
- 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++;
- }
+// 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;
}
-
- 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;
+ 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
}
- 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[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];
+ *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;
}
- 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
+ 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;
}
- // TODO: take top 3 answers and compare to known Field clocks to get top 2
+ return -5;
+}
- uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
- if (fskAdj) return fcs;
- return fcLens[best1];
+// 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)
+ uint8_t preamble[] = {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 preamble_i[] = {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;
+ if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
+ // if didn't find preamble try again inverting
+ if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
+ *invert ^= 1;
+ }
+ if (*size != 64 && *size != 224) return -2;
+ if (*invert==1)
+ for (size_t i = startidx; i < *size + startidx; i++)
+ bitStream[i] ^= 1;
+
+ return (int) startidx;
}
-//by marshmellow - demodulate PSK1 wave
-//uses wave lengths (# Samples)
-int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
-{
- if (size == 0) return -1;
- uint16_t loopCnt = 4096; //don't need to loop through entire array...
- if (*size<loopCnt) loopCnt = *size;
+// 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;
- size_t numBits=0;
- uint8_t curPhase = *invert;
- size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
- uint16_t fc=0, fullWaveLen=0, tol=1;
- uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
- fc = countFC(dest, *size, 1);
- uint8_t fc2 = fc >> 8;
- if (fc2 == 10) return -1; //fsk found - quit
- fc = fc & 0xFF;
- if (fc!=2 && fc!=4 && fc!=8) return -1;
- //PrintAndLog("DEBUG: FC: %d",fc);
- *clock = DetectPSKClock(dest, *size, *clock);
- if (*clock == 0) return -1;
+ // 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};
- //find start of modulating data in trace
- uint8_t threshold_value = 123; //-5
- i = findModStart(dest, *size, threshold_value, fc);
+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
+ if (errChk == 0) return -3; //preamble not found
- //find first phase shift
- int avgWaveVal=0, lastAvgWaveVal=0;
- waveStart = i;
- for (; i<loopCnt; i++) {
- // find peak
- if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[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+3)){ //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 > threshold_value) curPhase ^= 1;
- break;
- }
- waveStart = i+1;
- avgWaveVal = 0;
- }
- avgWaveVal += dest[i+2];
- }
- 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);
- }
- //advance bits
- numBits += (firstFullWave / *clock);
- //set start of wave as clock align
- lastClkBit = firstFullWave;
- if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
- 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;
- lastAvgWaveVal = avgWaveVal/waveLenCnt;
- if (waveLenCnt > fc){
- //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
- //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 = 0;
- waveStart = i+1;
- }
- }
- avgWaveVal += dest[i+1];
+ 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;
}
- *size = numBits;
- return errCnt;
+ return (int)startIdx;
}
-//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 bufsize = *size;
- //need to loop through all samples and identify our clock, look for the ST pattern
- uint8_t fndClk[] = {8,16,32,40,50,64,128};
- int clk = 0;
- int tol = 0;
- int i, j, skip, start, end, low, high, minClk, waveStart;
- bool complete = false;
- int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
- int waveLen[bufsize / 32]; // 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));
+// 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;
- if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
- if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
- return false; //just noise
- }
- i = 0;
- j = 0;
- minClk = 255;
- // get to first full low to prime loop and skip incomplete first pulse
- while ((buffer[i] < high) && (i < bufsize))
- ++i;
- while ((buffer[i] > low) && (i < bufsize))
- ++i;
- skip = i;
+ 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;
+}
- // populate tmpbuff buffer with pulse lengths
- while (i < bufsize) {
- // measure from low to low
- while ((buffer[i] > low) && (i < bufsize))
- ++i;
- start= i;
- while ((buffer[i] < high) && (i < bufsize))
- ++i;
- //first high point for this wave
- waveStart = i;
- while ((buffer[i] > low) && (i < bufsize))
- ++i;
- if (j >= (bufsize/32)) {
- break;
- }
- waveLen[j] = i - waveStart; //first high to first low
- tmpbuff[j++] = i - start;
- if (i-start < minClk && i < bufsize) {
- minClk = i - start;
- }
- }
- // set clock - might be able to get this externally and remove this work...
- if (!clk) {
- for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
- tol = fndClk[clkCnt]/8;
- if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
- clk=fndClk[clkCnt];
- break;
- }
- }
- // clock not found - ERROR
- if (!clk) {
- if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
- return false;
- }
- } else tol = clk/8;
+// 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;
- *foundclock = clk;
+ // 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?
- // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
- start = -1;
- for (i = 0; i < j - 4; ++i) {
- skip += tmpbuff[i];
- if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
- if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
- if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
- if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
- start = i + 3;
- break;
- }
- }
- }
- }
- }
- // first ST not found - ERROR
- if (start < 0) {
- 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: %d, j=%d",start, 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
+ 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;
+}
- // now do it again to find the end
- end = skip;
- for (i += 3; i < j - 4; ++i) {
- end += tmpbuff[i];
- if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
- if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
- if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
- if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
- complete = true;
- break;
- }
- }
- }
- }
- }
- end -= phaseoff;
- //didn't find second ST - ERROR
- if (!complete) {
- if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
- return false;
- }
- 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/8)] <= 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/8); ++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);
+// 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;
- // 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+3]<high && buffer[dataloc+3]>low) {
- for(i=0; i < clk/2-tol; ++i) {
- buffer[dataloc+i] = high+5;
- }
- }
- for (i=0; i<datalen; ++i) {
- if (i+newloc < bufsize) {
- if (i+newloc < dataloc)
- buffer[i+newloc] = buffer[dataloc];
+ 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;
+}
- 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 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;
}
projects / proxmark3-svn / blobdiff