git.zerfleddert.de Git - proxmark3-svn/blobdiff

// at your option, any later version. See the LICENSE.txt file for the text of

// the license.

//-----------------------------------------------------------------------------

// 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, ...){}

//to allow debug print calls when used not on device

void dummy(char *fmt, ...){}

-

#ifndef ON_DEVICE

#include "ui.h"

#include "cmdparser.h"

#ifndef ON_DEVICE

#include "ui.h"

#include "cmdparser.h"

#define prnt dummy

#endif

#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++){

//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

}

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

*high=0;

*low=255;

// get high and low thresholds

if (BitStream[i] > *high) *high = BitStream[i];

if (BitStream[i] < *low) *low = BitStream[i];

}

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;

*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

// 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

}

// 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++) {

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) {

// 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

}

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

parityWd = 0;

}

// if we got here then all the parities passed

- //return ID start index and size

+ //return size

return bitCnt;

}

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

// 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) {

uint32_t parityWd = 0;

size_t j = 0, bitCnt = 0;

for (int word = 0; word < sourceLen; word+=pLen-1) {

return bitCnt;

}

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++)

{

uint32_t num = 0;

for(int i = 0 ; i < numbits ; i++)

{

}

//least significant bit first

}

//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++)

{

uint32_t num = 0;

for(int i = 0 ; i < numbits ; i++)

{

return num;

}

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)

-{

- return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;

-}

-

// 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) {

// 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) {

return false;

}

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;

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;

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;

thresholdCnt++;

if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;

isAboveThreshold = true;

return i;

}

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)

-{

- //sanity checks

- if (*size < 64) return 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};

- // 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

+ for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++)

+ if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1)

+ return fndClk[clkCnt];

- //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 {

- return 0;

- }

- return 1;

+ 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;

- } else if (!waveHigh) {

- 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

-//amplify based on ask edge detection

-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

}

//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) {

}

uint32_t manchesterEncode2Bytes(uint16_t datain) {

//by marshmellow

//encode binary data into binary manchester

//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 (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;

}

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;

+// 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++;

}

- *size=bitnum;

- return errCnt;

+ if (!allArePeaks){

+ if (cntPeaks > 300) return true;

+ }

+ return allArePeaks;

}

+//**********************************************************************************************

+//-------------------Clock / Bitrate Detection Section------------------------------------------

+//**********************************************************************************************

+

// 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};

+// 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);

- 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;

+ // loop through all samples

+ while (i < size) {

+ // measure from low to low

+ startwave = i;

+

+ getNextHigh(dest, size, high, &i);

+ getNextLow(dest, size, low, &i);

+ //get minimum measured distance

+ if (i-startwave < minClk && i < size) {

+ minClk = i - startwave;

+ shortestWaveIdx = startwave;

+ }

}

- return -5; //spacer bits not found - not a valid gproxII

+ // set clock

+ if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk);

+ *clock = getClosestClock(minClk);

+ if (*clock == 0)

+ return 0;

+

+ return shortestWaveIdx;

}

-//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

-

- //find start of modulating data in trace

- idx = findModStart(dest, size, threshold_value, fchigh);

+// 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

- // Need to threshold first sample

- if(dest[idx] < threshold_value) dest[0] = 0;

- else dest[0] = 1;

- idx++;

+ //get high and low peak

+ int peak, low;

+ if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;

- size_t numBits = 0;

- // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)

- // or 10 (fc/10) cycles but in practice due to noise etc we may end up with 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

+ //test for large clean peaks

+ if (!clockFnd){

+ if (DetectCleanAskWave(dest, size, peak, low)==1){

+ int ans = DetectStrongAskClock(dest, size, peak, low, clock);

+ if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);

+ if (ans > 0) {

+ return ans; //return shortest wave start position

+ }

+ uint8_t ii;

+ uint8_t clkCnt, tol = 0;

+ uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};

+ uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};

+ size_t errCnt = 0;

+ size_t arrLoc, loopEnd;

- if (dest[idx] < threshold_value) dest[idx] = 0;

- else dest[idx] = 1;

+ if (clockFnd>0) {

+ clkCnt = clockFnd;

+ clkEnd = clockFnd+1;

+ }

+ else clkCnt=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 (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){

- dest[numBits-1]=1;

- }

- dest[numBits++]=1;

+ //test each valid clock from smallest to greatest to see which lines up

+ for(; clkCnt < clkEnd; clkCnt++){

+ if (clk[clkCnt] <= 32){

+ tol=1;

+ }else{

+ tol=0;

+ }

+ //if no errors allowed - keep start within the first clock

+ if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;

+ bestErr[clkCnt]=1000;

+ //try lining up the peaks by moving starting point (try first few clocks)

+ for (ii=0; ii < loopCnt; ii++){

+ if (dest[ii] < peak && dest[ii] > low) continue;

- } 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;

+ 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;

}

- last_transition = idx;

}

- return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 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;

+ }

+ 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];

}

-//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 (n == 0) n = 1;

+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;

- //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;

+ //find first valid beginning of a high or low wave

+ while ((dest[i] >= peak || dest[i] <= low) && (i < size))

+ ++i;

+ while ((dest[i] < peak && dest[i] > low) && (i < size))

+ ++i;

+ lastWasHigh = (dest[i] >= peak);

+

+ if (i==size) return 0;

+ transition1 = i;

+

+ for (;i < size; i++) {

+ if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {

+ lastWasHigh = (dest[i] >= peak);

+ if (i-transition1 < lowestTransition) lowestTransition = i-transition1;

+ transition1 = i;

}

- memset(dest+numBits, dest[idx-1]^invert , n);

- numBits += n;

}

- return numBits;

+ if (lowestTransition == 255) lowestTransition = 0;

+ if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);

+ return lowestTransition;

}

-//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;

-}

-

-// 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;

+//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;

- 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

+ //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

+ 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;

+ }

}

- *hi2 = (*hi2<<1)|(*hi>>31);

- *hi = (*hi<<1)|(*lo>>31);

- //Then, shift in a 0 or one into low

- if (dest[idx] && !dest[idx+1]) // 1 0

- *lo=(*lo<<1)|1;

- else // 0 1

- *lo=(*lo<<1)|0;

}

- return (int)startIdx;

-}

-

-// loop to get raw paradox waveform then FSK demodulate the TAG ID from it

-int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)

-{

- if (justNoise(dest, *size)) return -1;

-

- size_t numStart=0, size2=*size, startIdx=0;

- // FSK demodulator

- *size = fskdemod(dest, size2,50,1,10,8); //fsk2a

- if (*size < 96) return -2;

-

- // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1

- uint8_t preamble[] = {0,0,0,0,1,1,1,1};

-

- uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

- if (errChk == 0) return -3; //preamble not found

-

- numStart = startIdx + sizeof(preamble);

- // final loop, go over previously decoded FSK data and manchester decode into usable tag ID

- for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){

- if (dest[idx] == dest[idx+1])

- return -4; //not manchester data

- *hi2 = (*hi2<<1)|(*hi>>31);

- *hi = (*hi<<1)|(*lo>>31);

- //Then, shift in a 0 or one into low

- if (dest[idx] && !dest[idx+1]) // 1 0

- *lo=(*lo<<1)|1;

- else // 0 1

- *lo=(*lo<<1)|0;

+ 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;

+ }

}

- return (int)startIdx;

-}

-

-int IOdemodFSK(uint8_t *dest, size_t size)

-{

- if (justNoise(dest, size)) return -1;

- //make sure buffer has data

- if (size < 66*64) return -2;

- // FSK demodulator

- size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64

- if (size < 65) return -3; //did we get a good demod?

- //Index map

- //0 10 20 30 40 50 60

- //| | | | | | |

- //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23

- //-----------------------------------------------------------------------------

- //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11

- //

- //XSF(version)facility:codeone+codetwo

- //Handle the data

- size_t startIdx = 0;

- uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};

- uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);

- if (errChk == 0) return -4; //preamble not found

-

- if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){

- //confirmed proper separator bits found

- //return start position

- return (int) startIdx;

+ 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);

}

- return -5;

-}

-

-// by marshmellow

-// find viking preamble 0xF200 in already demoded data

-int VikingDemod_AM(uint8_t *dest, size_t *size) {

- //make sure buffer has data

- if (*size < 64*2) return -2;

-

- size_t startIdx = 0;

- uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

- uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

- if (errChk == 0) return -4; //preamble not found

- uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)

- ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)

- ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);

- if ( checkCalc != 0xA8 ) return -5;

- if (*size != 64) return -6;

- //return start position

- return (int) startIdx;

+ *clockStartIdx = bestStart[best];

+ return clk[best];

}

-// find presco preamble 0x10D in already demoded data

-int PrescoDemod(uint8_t *dest, size_t *size) {

- //make sure buffer has data

- if (*size < 64*2) return -2;

-

- size_t startIdx = 0;

- uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};

- uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

- if (errChk == 0) return -4; //preamble not found

- //return start position

- return (int) startIdx;

-}

+//by marshmellow

+//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;

-// 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;

+ // 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;

- size_t startIdx = 0;

- uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};

+ 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++;

+ }

+

+ 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

- uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

- if (errChk == 0) return -2; //preamble not found

- return (int)startIdx;

+ uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;

+ if (fskAdj) return fcs;

+ return (uint16_t)fcLens[best2] << 8 | fcLens[best1];

}

-// 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;

+//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;

- if (justNoise(dest, *size)) return -2;

+ 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 -1;

+ if (*fc!=2 && *fc!=4 && *fc!=8) return -1;

- // FSK demodulator

- *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50

- if (*size < 96) return -3; //did we get a good demod?

+ //if we already have a valid clock quit

+ size_t i=1;

+ for (; i < 8; ++i)

+ if (clk[i] == clock) return clock;

- 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;

-}

+ size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;

-// 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;

+ 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};

- //test samples are not just noise

- if (justNoise(dest, *size)) return -1;

+ //find start of modulating data in trace

+ i = findModStart(dest, size, *fc);

- // FSK demodulator

- *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50

- if (*size < 128) return -2; //did we get a good demod?

+ 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;

+ }

- 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;

-}

+ *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);

-// 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;

+ 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 allArePeaks;

+ return clk[best];

}

-// 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, int *clock) {

- uint8_t fndClk[] = {8,16,32,40,50,64,128};

- 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

- while ((dest[i] < high) && (i < size))

- ++i;

- while ((dest[i] > low) && (i < size))

- ++i;

- // 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;

- shortestWaveIdx = startwave;

+//int DetectPSKClock(uint8_t dest[], size_t size, int clock) {

+// size_t firstPhaseShift = 0;

+// uint8_t curPhase = 0;

+// return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift, &curPhase);

+//}

+

+//by marshmellow

+//detects the bit clock for FSK given the high and low Field Clocks

+uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {

+ uint8_t clk[] = {8,16,32,40,50,64,100,128,0};

+ uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

+ uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

+ uint8_t rfLensFnd = 0;

+ uint8_t lastFCcnt = 0;

+ uint16_t fcCounter = 0;

+ uint16_t rfCounter = 0;

+ uint8_t firstBitFnd = 0;

+ size_t i;

+ if (size == 0) return 0;

+

+ uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);

+ rfLensFnd=0;

+ fcCounter=0;

+ rfCounter=0;

+ firstBitFnd=0;

+ //PrintAndLog("DEBUG: fcTol: %d",fcTol);

+ // prime i to first peak / up transition

+ for (i = 160; i < size-20; i++)

+ if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])

+ break;

+

+ for (; i < size-20; i++){

+ fcCounter++;

+ rfCounter++;

+

+ if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])

+ continue;

+ // else new peak

+ // if we got less than the small fc + tolerance then set it to the small fc

+ // if it is inbetween set it to the last counter

+ if (fcCounter < fcHigh && fcCounter > fcLow)

+ fcCounter = lastFCcnt;

+ else if (fcCounter < fcLow+fcTol)

+ fcCounter = fcLow;

+ else //set it to the large fc

+ fcCounter = fcHigh;

+

+ //look for bit clock (rf/xx)

+ if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){

+ //not the same size as the last wave - start of new bit sequence

+ if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit

+ for (int ii=0; ii<15; ii++){

+ if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){

+ rfCnts[ii]++;

+ rfCounter = 0;

+ break;

+ }

+ if (rfCounter > 0 && rfLensFnd < 15){

+ //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);

+ rfCnts[rfLensFnd]++;

+ rfLens[rfLensFnd++] = rfCounter;

+ }

+ } else {

+ *firstClockEdge = i;

+ firstBitFnd++;

+ }

+ rfCounter=0;

+ lastFCcnt=fcCounter;

}

+ fcCounter=0;

}

- // 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) {

- *clock = fndClk[clkCnt];

- return shortestWaveIdx;

+ 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;

+ }

}

- return 0;

-}

-// by marshmellow

-// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)

-// maybe somehow adjust peak trimming value based on samples to fix?

-// 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

+ if (ii<2) return 0; // oops we went too far

- //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

+ return clk[ii];

+}

+

+uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {

+ int firstClockEdge = 0;

+ return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);

+}

+

+//**********************************************************************************************

+//--------------------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;

+ }

}

- 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;

+ return false;

+}

+//by marshmellow

+//attempt to identify a Sequence Terminator in ASK modulated raw wave

+bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {

+ size_t bufsize = *size;

+ //need to loop through all samples and identify our clock, look for the ST pattern

+ int clk = 0;

+ int tol = 0;

+ int j=0, high, low, skip=0, start=0, end=0, minClk=255;

+ size_t i = 0;

+ //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]

+ int tmpbuff[bufsize / LOWEST_DEFAULT_CLOCK]; // low to low wave count //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured

+ int waveLen[bufsize / LOWEST_DEFAULT_CLOCK]; // high to low wave count //if clock is larger then we waste memory in array size that is not needed...

+ //size_t testsize = (bufsize < 512) ? bufsize : 512;

+ int phaseoff = 0;

+ high = low = 128;

+ memset(tmpbuff, 0, sizeof(tmpbuff));

+ memset(waveLen, 0, sizeof(waveLen));

- if (clockFnd>0) {

- clkCnt = clockFnd;

- clkEnd = clockFnd+1;

+ 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;

}

- else clkCnt=1;

+ *foundclock = clk;

- //test each valid clock from smallest to greatest to see which lines up

- for(; clkCnt < clkEnd; clkCnt++){

- if (clk[clkCnt] <= 32){

- tol=1;

- }else{

- tol=0;

- }

- //if no errors allowed - keep start within the first clock

- if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;

- bestErr[clkCnt]=1000;

- //try lining up the peaks by moving starting point (try first few clocks)

- for (ii=0; ii < loopCnt; ii++){

- if (dest[ii] < peak && dest[ii] > low) continue;

+ 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

- 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++;

- }

+ // 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;

}

- //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;

+ }

+

+ 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;

}

- //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;

+ } //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];

}

- }

- 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 (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++;

}

- 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]);

+ 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;

}

- if (!clockFnd) *clock = clk[best];

- return bestStart[best];

+ *size = newloc;

+ return true;

}

-

-int DetectPSKClock(uint8_t dest[], size_t size, int clock) {

- int firstPhaseShift = 0;

- return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);

+bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {

+ size_t ststart = 0, stend = 0;

+ return DetectST_ext(buffer, size, foundclock, &ststart, &stend);

}

//by marshmellow

}

//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_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {

- 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;

- }

+//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;

}

- *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--){

- 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);

+ *size = bitCnt;

+ return errCnt;

+}

- 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];

+//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 (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((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 (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);

+ if(bitnum>MaxBits) break;

}

- return clk[best];

+ *size=bitnum;

+ 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;

-

- //find first valid beginning of a high or low wave

- while ((dest[i] >= peak || dest[i] <= low) && (i < size))

- ++i;

- while ((dest[i] < peak && dest[i] > low) && (i < size))

- ++i;

- lastWasHigh = (dest[i] >= peak);

-

- if (i==size) return 0;

- transition1 = i;

+//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++;

- 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;

+ if (bestErr>errCnt){

+ bestErr=errCnt;

+ bestRun=ii;

}

+ errCnt=0;

}

- if (lowestTransition == 255) lowestTransition = 0;

- if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);

- return lowestTransition;

-}

-

-int DetectNRZClock(uint8_t dest[], size_t size, int clock) {

- size_t bestStart=0;

- return DetectNRZClock_ext(dest, size, clock, &bestStart);

+ *alignPos=bestRun;

+ //decode

+ for (i=bestRun; i < *size-3; i+=2){

+ if(BitStream[i] == 1 && (BitStream[i+1] == 0)){

+ BitStream[bitnum++]=invert;

+ } else if((BitStream[i] == 0) && BitStream[i+1] == 1){

+ BitStream[bitnum++]=invert^1;

+ } else {

+ BitStream[bitnum++]=7;

+ }

+ if(bitnum>MaxBits) break;

+ }

+ *size=bitnum;

+ return bestErr;

}

-

//by marshmellow

-//detect nrz clock by reading #peaks vs no peaks(or errors)

-int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {

- size_t i=0;

- uint8_t clk[]={8,16,32,40,50,64,100,128,255};

- size_t loopCnt = 4096; //don't need to loop through entire array...

- if (size == 0) return 0;

- if (size<loopCnt) loopCnt = size-20;

- //if we already have a valid clock quit

- for (; i < 8; ++i)

- if (clk[i] == clock) return clock;

-

- //get high and low peak

- int peak, low;

- if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 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 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;

+//demodulates strong heavily clipped samples

+int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)

+{

+ *startIdx=0;

+ size_t bitCnt=0, smplCnt=1, errCnt=0;

+ bool waveHigh = (BinStream[0] >= high);

+ for (size_t i=1; i < *size; i++){

+ if (BinStream[i] >= high && waveHigh){

smplCnt++;

- } else {

- 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;

- }

- 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] < 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;

+ } 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;

+ } else if (!waveHigh) {

+ BinStream[bitCnt++] = invert ^ 1;

}

+ if (*startIdx==0) *startIdx = i-clk;

+ waveHigh = !waveHigh;

+ smplCnt = 0;

+ } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock

+ if (waveHigh) {

+ BinStream[bitCnt++] = invert;

+ } else if (!waveHigh) {

+ BinStream[bitCnt++] = invert ^ 1;

+ }

+ if (*startIdx==0) *startIdx = i-(clk/2);

+ waveHigh = !waveHigh;

+ smplCnt = 0;

+ } else {

+ smplCnt++;

+ //transition bit oops

}

- 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 { //haven't hit new high or new low yet

+ smplCnt++;

}

- } 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);

}

- *clockStartIdx = bestStart[best];

- return clk[best];

+ *size = bitCnt;

+ return errCnt;

}

-// by marshmellow

-// convert psk1 demod to psk2 demod

-// only transition waves are 1s

-void psk1TOpsk2(uint8_t *BitStream, size_t size)

-{

- size_t i=1;

- uint8_t lastBit=BitStream[0];

- for (; i<size; i++){

- if (BitStream[i]==7){

- //ignore errors

- } else if (lastBit!=BitStream[i]){

- lastBit=BitStream[i];

- BitStream[i]=1;

- } else {

- BitStream[i]=0;

+//by marshmellow

+//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester

+int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {

+ if (*size==0) return -1;

+ int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default

+ if (*clk==0 || start < 0) return -3;

+ if (*invert != 1) *invert = 0;

+ if (amp==1) askAmp(BinStream, *size);

+ if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);

+

+ //start pos from detect ask clock is 1/2 clock offset

+ // NOTE: can be negative (demod assumes rest of wave was there)

+ *startIdx = start - (*clk/2);

+ uint8_t initLoopMax = 255;

+ if (initLoopMax > *size) initLoopMax = *size;

+ // Detect high and lows

+ //25% clip in case highs and lows aren't clipped [marshmellow]

+ int high, low;

+ if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)

+ return -2; //just noise

+

+ size_t errCnt = 0;

+ // if clean clipped waves detected run alternate demod

+ if (DetectCleanAskWave(BinStream, *size, high, low)) {

+ if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");

+ errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);

+ if (askType) { //askman

+ uint8_t alignPos = 0;

+ errCnt = manrawdecode(BinStream, size, 0, &alignPos);

+ *startIdx += *clk/2 * alignPos;

+ if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);

+ return errCnt;

+ } else { //askraw

+ return errCnt;

}

- return;

-}

+ if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);

+ if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");

-// by marshmellow

-// convert psk2 demod to psk1 demod

-// from only transition waves are 1s to phase shifts change bit

-void psk2TOpsk1(uint8_t *BitStream, size_t size)

-{

- uint8_t phase=0;

- for (size_t i=0; i<size; i++){

- if (BitStream[i]==1){

- phase ^=1;

+ 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;

}

- BitStream[i]=phase;

+ if (bitnum >= MaxBits) break;

}

- return;

+ *size = bitnum;

+ return errCnt;

}

-// 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;

+int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {

+ int start = 0;

+ return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);

}

// by marshmellow - demodulate NRZ wave - requires a read with strong signal

// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak

}

// 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 nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {

if (justNoise(dest, *size)) return -1;

- *clk = DetectNRZClock(dest, *size, *clk);

+ 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;

if (*clk==0) return -2;

size_t i, gLen = 4096;

if (gLen>*size) gLen = *size-20;

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 (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;

}

lastBit = i-1;

}

return 0;

}

return 0;

}

-uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {

- int firstClockEdge = 0;

- return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);

+//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])

+size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {

+ size_t last_transition = 0;

+ size_t idx = 1;

+ if (fchigh==0) fchigh=10;

+ if (fclow==0) fclow=8;

+ //set the threshold close to 0 (graph) or 128 std to avoid static

+ size_t preLastSample = 0;

+ size_t LastSample = 0;

+ size_t currSample = 0;

+ if ( size < 1024 ) return 0; // not enough samples

+

+ //find start of modulating data in trace

+ idx = findModStart(dest, size, fchigh);

+ // Need to threshold first sample

+ if(dest[idx] < FSK_PSK_THRESHOLD) dest[0] = 0;

+ else dest[0] = 1;

+

+ last_transition = idx;

+ idx++;

+ size_t numBits = 0;

+ // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)

+ // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere

+ // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10

+ // (could also be fc/5 && fc/7 for fsk1 = 4-9)

+ for(; idx < size; idx++) {

+ // threshold current value

+ if (dest[idx] < FSK_PSK_THRESHOLD) dest[idx] = 0;

+ else dest[idx] = 1;

+

+ // Check for 0->1 transition

+ if (dest[idx-1] < dest[idx]) {

+ preLastSample = LastSample;

+ LastSample = currSample;

+ currSample = idx-last_transition;

+ if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)

+ //do nothing with extra garbage

+ } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)

+ //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)

+ if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){

+ dest[numBits-1]=1;

+ }

+ dest[numBits++]=1;

+ if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;

+ } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage

+ //do nothing with beginning garbage and reset.. should be rare..

+ numBits = 0;

+ } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)

+ dest[numBits++]=1;

+ if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;

+ } else { //9+ = 10 sample waves (or 6+ = 7)

+ dest[numBits++]=0;

+ if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;

+ }

+ last_transition = idx;

+ }

+ return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0

}

-//by marshmellow

-//detects the bit clock for FSK given the high and low Field Clocks

-uint8_t detectFSKClk_ext(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;

+//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);

+ }

- 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;

+ //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;

+}

- for (; i < size-20; i++){

- fcCounter++;

- rfCounter++;

+//by marshmellow (from holiman's base)

+// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)

+int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {

+ // FSK demodulator

+ size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);

+ size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);

+ return size;

+}

- 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;

+int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {

+ int startIdx=0;

+ return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);

+}

- //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;

+// by marshmellow

+// convert psk1 demod to psk2 demod

+// only transition waves are 1s

+void psk1TOpsk2(uint8_t *BitStream, size_t size) {

+ size_t i=1;

+ uint8_t lastBit=BitStream[0];

+ for (; i<size; i++){

+ if (BitStream[i]==7){

+ //ignore errors

+ } else if (lastBit!=BitStream[i]){

+ lastBit=BitStream[i];

+ BitStream[i]=1;

+ } else {

+ BitStream[i]=0;

}

- fcCounter=0;

}

- uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;

+ return;

+}

- 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;

+// by marshmellow

+// convert psk2 demod to psk1 demod

+// from only transition waves are 1s to phase shifts change bit

+void psk2TOpsk1(uint8_t *BitStream, size_t size) {

+ uint8_t phase=0;

+ for (size_t i=0; i<size; i++){

+ if (BitStream[i]==1){

+ phase ^=1;

}

- 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]);

+ BitStream[i]=phase;

+ }

+ return;

+}

- // 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;

+//by marshmellow - demodulate PSK1 wave

+//uses wave lengths (# Samples)

+int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {

+ if (*size < 170) return -1;

+

+ uint8_t curPhase = *invert;

+ uint8_t fc=0;

+ size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;

+ uint16_t fullWaveLen=0, waveLenCnt=0, avgWaveVal;

+ uint16_t errCnt=0, errCnt2=0;

+

+ *clock = DetectPSKClock(dest, *size, *clock, &firstFullWave, &curPhase, &fc);

+ if (*clock == 0) return -1;

+ //if clock detect found firstfullwave...

+ uint16_t tol = fc/2;

+ if (firstFullWave == 0) {

+ //find start of modulating data in trace

+ i = findModStart(dest, *size, fc);

+ //find first phase shift

+ firstFullWave = pskFindFirstPhaseShift(dest, *size, &curPhase, i, fc, &fullWaveLen);

+ if (firstFullWave == 0) {

+ // no phase shift detected - could be all 1's or 0's - doesn't matter where we start

+ // so skip a little to ensure we are past any Start Signal

+ firstFullWave = 160;

+ memset(dest, curPhase, firstFullWave / *clock);

+ } else {

+ memset(dest, curPhase^1, firstFullWave / *clock);

+ }

+ } else {

+ memset(dest, curPhase^1, firstFullWave / *clock);

+ }

+ //advance bits

+ numBits += (firstFullWave / *clock);

+ *startIdx = firstFullWave - (*clock * numBits)+2;

+ //set start of wave as clock align

+ lastClkBit = firstFullWave;

+ if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);

+ if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);

+ waveStart = 0;

+ dest[numBits++] = curPhase; //set first read bit

+ for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++) {

+ //top edge of wave = start of new wave

+ if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]) {

+ if (waveStart == 0) {

+ waveStart = i+1;

+ waveLenCnt = 0;

+ avgWaveVal = dest[i+1];

+ } else { //waveEnd

+ waveEnd = i+1;

+ waveLenCnt = waveEnd-waveStart;

+ if (waveLenCnt > fc) {

+ //this wave is a phase shift

+ //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);

+ if (i+1 >= lastClkBit + *clock - tol) { //should be a clock bit

+ curPhase ^= 1;

+ dest[numBits++] = curPhase;

+ lastClkBit += *clock;

+ } else if (i < lastClkBit+10+fc) {

+ //noise after a phase shift - ignore

+ } else { //phase shift before supposed to based on clock

+ errCnt++;

+ dest[numBits++] = 7;

+ }

+ } else if (i+1 > lastClkBit + *clock + tol + fc) {

+ lastClkBit += *clock; //no phase shift but clock bit

+ dest[numBits++] = curPhase;

+ } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)

+ errCnt2++;

+ if(errCnt2 > 101) return errCnt2;

+ avgWaveVal += dest[i+1];

+ continue;

}

+ avgWaveVal = 0;

+ waveStart = i+1;

}

+ avgWaveVal += dest[i+1];

}

+ *size = numBits;

+ return errCnt;

+}

- if (ii<2) return 0; // oops we went too far

+int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {

+ int startIdx = 0;

+ return pskRawDemod_ext(dest, size, clock, invert, &startIdx);

+}

- return clk[ii];

+//**********************************************************************************************

+//-----------------Tag format detection section-------------------------------------------------

+//**********************************************************************************************

+

+// by marshmellow

+// FSK Demod then try to locate an AWID ID

+int AWIDdemodFSK(uint8_t *dest, size_t *size) {

+ //make sure buffer has enough data

+ if (*size < 96*50) return -1;

+

+ if (justNoise(dest, *size)) return -2;

+

+ // FSK demodulator

+ *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50

+ if (*size < 96) return -3; //did we get a good demod?

+

+ uint8_t preamble[] = {0,0,0,0,0,0,0,1};

+ size_t startIdx = 0;

+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

+ if (errChk == 0) return -4; //preamble not found

+ if (*size != 96) return -5;

+ return (int)startIdx;

}

//by marshmellow

}

//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

- 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++;

- }

+ //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;

}

-

- 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]);

+ return 1;

+}

+

+// Ask/Biphase Demod then try to locate an ISO 11784/85 ID

+// BitStream must contain previously askrawdemod and biphasedemoded data

+int FDXBdemodBI(uint8_t *dest, size_t *size) {

+ //make sure buffer has enough data

+ if (*size < 128) return -1;

+

+ size_t startIdx = 0;

+ uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};

+

+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

+ if (errChk == 0) return -2; //preamble not found

+ if (*size != 128) return -3; //wrong size for fdxb

+ //return start position

+ return (int)startIdx;

+}

+

+// by marshmellow

+// demod gProxIIDemod

+// error returns as -x

+// success returns start position in BitStream

+// BitStream must contain previously askrawdemod and biphasedemoded data

+int gProxII_Demod(uint8_t BitStream[], size_t *size) {

+ size_t startIdx=0;

+ uint8_t preamble[] = {1,1,1,1,1,0};

+

+ uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);

+ if (errChk == 0) return -3; //preamble not found

+ if (*size != 96) return -2; //should have found 96 bits

+ //check first 6 spacer bits to verify format

+ if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){

+ //confirmed proper separator bits found

+ //return start position

+ return (int) startIdx;

}

- 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];

+ 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) {

+ 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*2) return -2;

+ // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1

+ uint8_t preamble[] = {0,0,0,1,1,1,0,1};

+ // find bitstring in array

+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

+ if (errChk == 0) return -3; //preamble not found

+

+ numStart = startIdx + sizeof(preamble);

+ // final loop, go over previously decoded FSK data and manchester decode into usable tag ID

+ for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){

+ if (dest[idx] == dest[idx+1]){

+ return -4; //not manchester data

+ }

+ *hi2 = (*hi2<<1)|(*hi>>31);

+ *hi = (*hi<<1)|(*lo>>31);

+ //Then, shift in a 0 or one into low

+ if (dest[idx] && !dest[idx+1]) // 1 0

+ *lo=(*lo<<1)|1;

+ else // 0 1

+ *lo=(*lo<<1)|0;

}

- 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) {

+ if (justNoise(dest, size)) return -1;

+ //make sure buffer has data

+ if (size < 66*64) return -2;

+ // FSK demodulator

+ size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64

+ if (size < 65) return -3; //did we get a good demod?

+ //Index map

+ //0 10 20 30 40 50 60

+ //| | | | | | |

+ //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23

+ //-----------------------------------------------------------------------------

+ //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11

+ //

+ //XSF(version)facility:codeone+codetwo

+ //Handle the data

+ size_t startIdx = 0;

+ uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};

+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);

+ if (errChk == 0) return -4; //preamble not found

+

+ if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){

+ //confirmed proper separator bits found

+ //return start position

+ return (int) startIdx;

}

- // TODO: take top 3 answers and compare to known Field clocks to get top 2

+ return -5;

+}

+

+// 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;

- uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;

- if (fskAdj) return fcs;

- return fcLens[best1];

+ 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) {

+ 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;

- 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;

}

-bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {

- size_t ststart = 0, stend = 0;

- return DetectST_ext(buffer, size, foundclock, &ststart, &stend);

-}

+// 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

-//attempt to identify a Sequence Terminator in ASK modulated raw wave

-bool DetectST_ext(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

- 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));

+ 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;

+}

- 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;

+// 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;

- // 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;

+ //test samples are not just noise

+ if (justNoise(dest, *size)) return -1;

- *foundclock = clk;

+ // FSK demodulator

+ *size = fskdemod(dest, *size, 50, 1, 10, 8); // 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);

- 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+3]<high && buffer[dataloc+3]>low) {

- for(i=0; i < clk/2-tol; ++i) {

- buffer[dataloc+i] = high+5;

- }

- } //test for single sample outlier (high between two lows) in the case of very strong waves

- if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {

- buffer[dataloc] = buffer[dataloc+2];

- buffer[dataloc+1] = buffer[dataloc+2];

- }

- 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];

+// 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;

- 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;

+ size_t startIdx = 0;

+ uint8_t preamble[] = {1,1,1,1,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};

+ uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);

+ if (errChk == 0) return -4; //preamble not found

+ uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)

+ ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)

+ ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);

+ if ( checkCalc != 0xA8 ) return -5;

+ if (*size != 64) return -6;

+ //return start position

+ return (int) startIdx;

}

// by iceman

}

// by iceman