move new functions to utilities area
[proxmark3-svn] / common / lfdemod.c
CommitLineData
eb191de6 1//-----------------------------------------------------------------------------
ba1a299c 2// Copyright (C) 2014
eb191de6 3//
4// This code is licensed to you under the terms of the GNU GPL, version 2 or,
5// at your option, any later version. See the LICENSE.txt file for the text of
6// the license.
7//-----------------------------------------------------------------------------
bf74114d 8// Low frequency demod/decode commands - by marshmellow, holiman, iceman and
9// many others who came before
4d3c1796 10//
11// NOTES:
12// LF Demod functions are placed here to allow the flexability to use client or
13// device side. Most BUT NOT ALL of these functions are currenlty safe for
14// device side use currently. (DetectST for example...)
15//
16// There are likely many improvements to the code that could be made, please
17// make suggestions...
18//
bf74114d 19// we tried to include author comments so any questions could be directed to
20// the source.
21//
4d3c1796 22// There are 4 main sections of code below:
23// Utilities Section:
24// for general utilities used by multiple other functions
4d3c1796 25// Clock / Bitrate Detection Section:
26// for clock detection functions for each modulation
d5051b98 27// Modulation Demods &/or Decoding Section:
28// for main general modulation demodulating and encoding decoding code.
4d3c1796 29// Tag format detection section:
30// for detection of specific tag formats within demodulated data
31//
32// marshmellow
eb191de6 33//-----------------------------------------------------------------------------
34
d5051b98 35#include <string.h> // for memset, memcmp and size_t
36#include <stdint.h> // for uint_32+
37#include <stdbool.h> // for bool
6fe5c94b 38
d5051b98 39//**********************************************************************************************
40//---------------------------------Utilities Section--------------------------------------------
41//**********************************************************************************************
bf74114d 42
d1869c33 43//to allow debug print calls when used not on device
6fe5c94b 44void dummy(char *fmt, ...){}
6fe5c94b 45#ifndef ON_DEVICE
46#include "ui.h"
709665b5 47#include "cmdparser.h"
48#include "cmddata.h"
6fe5c94b 49#define prnt PrintAndLog
50#else
709665b5 51 uint8_t g_debugMode=0;
6fe5c94b 52#define prnt dummy
53#endif
6fe5c94b 54
bf74114d 55uint8_t justNoise(uint8_t *BitStream, size_t size) {
a1d17964 56 static const uint8_t THRESHOLD = 123;
57 //test samples are not just noise
58 uint8_t justNoise1 = 1;
59 for(size_t idx=0; idx < size && justNoise1 ;idx++){
60 justNoise1 = BitStream[idx] < THRESHOLD;
61 }
62 return justNoise1;
63}
64
1e090a61 65//by marshmellow
872e3d4d 66//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
bf74114d 67int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) {
1e090a61 68 *high=0;
69 *low=255;
70 // get high and low thresholds
2eec55c8 71 for (size_t i=0; i < size; i++){
1e090a61 72 if (BitStream[i] > *high) *high = BitStream[i];
73 if (BitStream[i] < *low) *low = BitStream[i];
74 }
75 if (*high < 123) return -1; // just noise
75cbbe9a 76 *high = ((*high-128)*fuzzHi + 12800)/100;
77 *low = ((*low-128)*fuzzLo + 12800)/100;
1e090a61 78 return 1;
79}
80
a1d17964 81// by marshmellow
82// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
83// returns 1 if passed
bf74114d 84uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
a1d17964 85 uint8_t ans = 0;
86 for (uint8_t i = 0; i < bitLen; i++){
87 ans ^= ((bits >> i) & 1);
88 }
e39a92bb 89 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
a1d17964 90 return (ans == pType);
91}
92
709665b5 93// by marshmellow
94// takes a array of binary values, start position, length of bits per parity (includes parity bit),
88e85bde 95// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
bf74114d 96size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) {
709665b5 97 uint32_t parityWd = 0;
98 size_t j = 0, bitCnt = 0;
e39a92bb 99 for (int word = 0; word < (bLen); word+=pLen) {
100 for (int bit=0; bit < pLen; bit++) {
709665b5 101 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
102 BitStream[j++] = (BitStream[startIdx+word+bit]);
103 }
e88096ba 104 if (word+pLen > bLen) break;
e39a92bb 105
709665b5 106 j--; // overwrite parity with next data
107 // if parity fails then return 0
88e85bde 108 switch (pType) {
29435274 109 case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
110 case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
111 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
709665b5 112 }
113 bitCnt+=(pLen-1);
114 parityWd = 0;
115 }
116 // if we got here then all the parities passed
117 //return ID start index and size
118 return bitCnt;
119}
120
121// by marshmellow
122// takes a array of binary values, length of bits per parity (includes parity bit),
88e85bde 123// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
124// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
bf74114d 125size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) {
709665b5 126 uint32_t parityWd = 0;
127 size_t j = 0, bitCnt = 0;
128 for (int word = 0; word < sourceLen; word+=pLen-1) {
129 for (int bit=0; bit < pLen-1; bit++){
130 parityWd = (parityWd << 1) | BitSource[word+bit];
131 dest[j++] = (BitSource[word+bit]);
132 }
133 // if parity fails then return 0
88e85bde 134 switch (pType) {
135 case 3: dest[j++]=0; break; // marker bit which should be a 0
136 case 2: dest[j++]=1; break; // marker bit which should be a 1
137 default:
138 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
139 break;
709665b5 140 }
141 bitCnt += pLen;
142 parityWd = 0;
143 }
144 // if we got here then all the parities passed
145 //return ID start index and size
146 return bitCnt;
147}
148
bf74114d 149uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) {
709665b5 150 uint32_t num = 0;
151 for(int i = 0 ; i < numbits ; i++)
152 {
153 num = (num << 1) | (*src);
154 src++;
155 }
156 return num;
157}
158
159//least significant bit first
bf74114d 160uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) {
709665b5 161 uint32_t num = 0;
162 for(int i = 0 ; i < numbits ; i++)
163 {
164 num = (num << 1) | *(src + (numbits-(i+1)));
165 }
166 return num;
167}
168
e88096ba 169// 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
170// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
171bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
59f726c9 172 // Sanity check. If preamble length is bigger than bitstream length.
e88096ba 173 if ( *size <= pLen ) return false;
59f726c9 174
e88096ba 175 uint8_t foundCnt = 0;
176 for (size_t idx = 0; idx < *size - pLen; idx++) {
177 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
e0165dcf 178 //first index found
179 foundCnt++;
e88096ba 180 if (foundCnt == 1) {
181 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
e0165dcf 182 *startIdx = idx;
e88096ba 183 if (findone) return true;
184 } else if (foundCnt == 2) {
e0165dcf 185 *size = idx - *startIdx;
e88096ba 186 return true;
e0165dcf 187 }
188 }
189 }
4c6ccc2b 190 return false;
191}
192
bf74114d 193//by marshmellow
194//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
195uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) {
196 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
197}
198
34ff8985 199// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
200size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
201 size_t i = 0;
202 size_t waveSizeCnt = 0;
203 uint8_t thresholdCnt = 0;
204 bool isAboveThreshold = dest[i++] >= threshold_value;
205 for (; i < size-20; i++ ) {
206 if(dest[i] < threshold_value && isAboveThreshold) {
207 thresholdCnt++;
208 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
209 isAboveThreshold = false;
210 waveSizeCnt = 0;
211 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
212 thresholdCnt++;
213 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
214 isAboveThreshold = true;
215 waveSizeCnt = 0;
216 } else {
217 waveSizeCnt++;
218 }
219 if (thresholdCnt > 10) break;
220 }
221 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
222 return i;
223}
224
d87bf156 225void getNextLow(uint8_t samples[], size_t size, int low, int *i) {
226 while ((samples[*i] > low) && (*i < size))
227 *i+=1;
228}
229
230void getNextHigh(uint8_t samples[], size_t size, int high, int *i) {
231 while ((samples[*i] < high) && (*i < size))
232 *i+=1;
233}
234
235// load wave counters
236bool loadWaveCounters(uint8_t samples[], size_t size, int lowToLowWaveLen[], int highToLowWaveLen[], int *waveCnt, int *skip, int *minClk, int *high, int *low) {
237 int i=0, start, waveStart;
238 size_t testsize = (size < 512) ? size : 512;
239
240 if ( getHiLo(samples, testsize, high, low, 80, 80) == -1 ) {
241 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
242 return false; //just noise
243 }
244
245 // get to first full low to prime loop and skip incomplete first pulse
246 getNextHigh(samples, size, *high, &i);
247 getNextLow(samples, size, *low, &i);
248 *skip = i;
249
250 // populate tmpbuff buffer with pulse lengths
251 while (i < size) {
252 // measure from low to low
253 getNextLow(samples, size, *low, &i);
254 start = i;
255
256 //find first high point for this wave
257 getNextHigh(samples, size, *high, &i);
258 waveStart = i;
259
260 getNextLow(samples, size, *low, &i);
261
262 if (*waveCnt >= (size/32))
263 break;
264
265 highToLowWaveLen[*waveCnt] = i - waveStart; //first high to first low
266 lowToLowWaveLen[*waveCnt] = i - start;
267 *waveCnt += 1;
268 if (i-start < *minClk && i < size) {
269 *minClk = i - start;
270 }
271 }
272 return true;
273}
274
2147c307 275//by marshmellow
4d3c1796 276//amplify based on ask edge detection - not accurate enough to use all the time
277void askAmp(uint8_t *BitStream, size_t size) {
16ea2b8c 278 uint8_t Last = 128;
fef74fdc 279 for(size_t i = 1; i<size; i++){
280 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
16ea2b8c 281 Last = 255;
282 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
283 Last = 0;
284
285 BitStream[i-1] = Last;
fef74fdc 286 }
287 return;
288}
f822a063 289
3606ac0a 290uint32_t manchesterEncode2Bytes(uint16_t datain) {
291 uint32_t output = 0;
292 uint8_t curBit = 0;
293 for (uint8_t i=0; i<16; i++) {
294 curBit = (datain >> (15-i) & 1);
295 output |= (1<<(((15-i)*2)+curBit));
296 }
297 return output;
298}
299
fef74fdc 300//by marshmellow
301//encode binary data into binary manchester
4d3c1796 302//NOTE: BitStream must have double the size available in memory to do the swap
303int ManchesterEncode(uint8_t *BitStream, size_t size) {
304 size_t modIdx=size, i=0;
fef74fdc 305 if (size>modIdx) return -1;
306 for (size_t idx=0; idx < size; idx++){
307 BitStream[idx+modIdx++] = BitStream[idx];
308 BitStream[idx+modIdx++] = BitStream[idx]^1;
309 }
310 for (; i<(size*2); i++){
4d3c1796 311 BitStream[i] = BitStream[i+size];
fef74fdc 312 }
313 return i;
314}
315
d5051b98 316// by marshmellow
317// to detect a wave that has heavily clipped (clean) samples
318uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) {
319 bool allArePeaks = true;
320 uint16_t cntPeaks=0;
321 size_t loopEnd = 512+160;
322 if (loopEnd > size) loopEnd = size;
323 for (size_t i=160; i<loopEnd; i++){
324 if (dest[i]>low && dest[i]<high)
325 allArePeaks = false;
326 else
327 cntPeaks++;
bf74114d 328 }
d5051b98 329 if (!allArePeaks){
330 if (cntPeaks > 300) return true;
331 }
332 return allArePeaks;
bf74114d 333}
4d3c1796 334
d5051b98 335//**********************************************************************************************
336//-------------------Clock / Bitrate Detection Section------------------------------------------
337//**********************************************************************************************
338
339// by marshmellow
340// to help detect clocks on heavily clipped samples
341// based on count of low to low
342int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock) {
343 uint8_t fndClk[] = {8,16,32,40,50,64,128};
344 size_t startwave;
345 size_t i = 100;
346 size_t minClk = 255;
347 int shortestWaveIdx = 0;
348 // get to first full low to prime loop and skip incomplete first pulse
349 while ((dest[i] < high) && (i < size))
4d3c1796 350 ++i;
d5051b98 351 while ((dest[i] > low) && (i < size))
4d3c1796 352 ++i;
4d3c1796 353
d5051b98 354 // loop through all samples
355 while (i < size) {
4d3c1796 356 // measure from low to low
d5051b98 357 while ((dest[i] > low) && (i < size))
4d3c1796 358 ++i;
d5051b98 359 startwave = i;
360 while ((dest[i] < high) && (i < size))
4d3c1796 361 ++i;
d5051b98 362 while ((dest[i] > low) && (i < size))
4d3c1796 363 ++i;
d5051b98 364 //get minimum measured distance
365 if (i-startwave < minClk && i < size) {
366 minClk = i - startwave;
367 shortestWaveIdx = startwave;
4d3c1796 368 }
369 }
d5051b98 370 // set clock
371 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
372 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
373 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) {
374 *clock = fndClk[clkCnt];
375 return shortestWaveIdx;
4d3c1796 376 }
4d3c1796 377 }
d5051b98 378 return 0;
379}
4d3c1796 380
d5051b98 381// by marshmellow
382// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
383// maybe somehow adjust peak trimming value based on samples to fix?
384// return start index of best starting position for that clock and return clock (by reference)
385int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) {
386 size_t i=1;
387 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
388 uint8_t clkEnd = 9;
389 uint8_t loopCnt = 255; //don't need to loop through entire array...
390 if (size <= loopCnt+60) return -1; //not enough samples
391 size -= 60; //sometimes there is a strange end wave - filter out this....
392 //if we already have a valid clock
393 uint8_t clockFnd=0;
394 for (;i<clkEnd;++i)
395 if (clk[i] == *clock) clockFnd = i;
396 //clock found but continue to find best startpos
397
398 //get high and low peak
399 int peak, low;
400 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
4d3c1796 401
d5051b98 402 //test for large clean peaks
403 if (!clockFnd){
404 if (DetectCleanAskWave(dest, size, peak, low)==1){
405 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
406 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
407 if (ans > 0) {
408 return ans; //return shortest wave start position
4d3c1796 409 }
4d3c1796 410 }
d5051b98 411 }
412 uint8_t ii;
413 uint8_t clkCnt, tol = 0;
414 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
415 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
416 size_t errCnt = 0;
417 size_t arrLoc, loopEnd;
4d3c1796 418
d5051b98 419 if (clockFnd>0) {
420 clkCnt = clockFnd;
421 clkEnd = clockFnd+1;
4d3c1796 422 }
d5051b98 423 else clkCnt=1;
4d3c1796 424
d5051b98 425 //test each valid clock from smallest to greatest to see which lines up
426 for(; clkCnt < clkEnd; clkCnt++){
427 if (clk[clkCnt] <= 32){
428 tol=1;
429 }else{
430 tol=0;
ba1a299c 431 }
d5051b98 432 //if no errors allowed - keep start within the first clock
433 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
434 bestErr[clkCnt]=1000;
435 //try lining up the peaks by moving starting point (try first few clocks)
436 for (ii=0; ii < loopCnt; ii++){
437 if (dest[ii] < peak && dest[ii] > low) continue;
11081e04 438
d5051b98 439 errCnt=0;
440 // now that we have the first one lined up test rest of wave array
441 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
442 for (i=0; i < loopEnd; ++i){
443 arrLoc = ii + (i * clk[clkCnt]);
444 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
445 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
446 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
447 }else{ //error no peak detected
448 errCnt++;
449 }
450 }
451 //if we found no errors then we can stop here and a low clock (common clocks)
452 // this is correct one - return this clock
453 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
454 if(errCnt==0 && clkCnt<7) {
455 if (!clockFnd) *clock = clk[clkCnt];
456 return ii;
457 }
458 //if we found errors see if it is lowest so far and save it as best run
459 if(errCnt<bestErr[clkCnt]){
460 bestErr[clkCnt]=errCnt;
461 bestStart[clkCnt]=ii;
462 }
4d3c1796 463 }
11081e04 464 }
d5051b98 465 uint8_t iii;
466 uint8_t best=0;
467 for (iii=1; iii<clkEnd; ++iii){
468 if (bestErr[iii] < bestErr[best]){
469 if (bestErr[iii] == 0) bestErr[iii]=1;
470 // current best bit to error ratio vs new bit to error ratio
471 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
472 best = iii;
473 }
4d3c1796 474 }
d5051b98 475 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]);
4d3c1796 476 }
d5051b98 477 if (!clockFnd) *clock = clk[best];
478 return bestStart[best];
11081e04 479}
480
d5051b98 481int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
482 //find shortest transition from high to low
483 size_t i = 0;
484 size_t transition1 = 0;
485 int lowestTransition = 255;
486 bool lastWasHigh = false;
487
488 //find first valid beginning of a high or low wave
489 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
490 ++i;
491 while ((dest[i] < peak && dest[i] > low) && (i < size))
492 ++i;
493 lastWasHigh = (dest[i] >= peak);
494
495 if (i==size) return 0;
496 transition1 = i;
497
498 for (;i < size; i++) {
499 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
500 lastWasHigh = (dest[i] >= peak);
501 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
502 transition1 = i;
503 }
4d3c1796 504 }
d5051b98 505 if (lowestTransition == 255) lowestTransition = 0;
506 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
507 return lowestTransition;
4d3c1796 508}
509
510//by marshmellow
d5051b98 511//detect nrz clock by reading #peaks vs no peaks(or errors)
512int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
513 size_t i=0;
514 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
515 size_t loopCnt = 4096; //don't need to loop through entire array...
516 if (size == 0) return 0;
517 if (size<loopCnt) loopCnt = size-20;
518 //if we already have a valid clock quit
519 for (; i < 8; ++i)
520 if (clk[i] == clock) return clock;
521
522 //get high and low peak
523 int peak, low;
524 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
525
526 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
527 size_t ii;
528 uint8_t clkCnt;
529 uint8_t tol = 0;
530 uint16_t smplCnt = 0;
531 int16_t peakcnt = 0;
532 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
533 uint16_t maxPeak = 255;
534 bool firstpeak = false;
535 //test for large clipped waves
536 for (i=0; i<loopCnt; i++){
537 if (dest[i] >= peak || dest[i] <= low){
538 if (!firstpeak) continue;
4d3c1796 539 smplCnt++;
d5051b98 540 } else {
541 firstpeak=true;
542 if (smplCnt > 6 ){
543 if (maxPeak > smplCnt){
544 maxPeak = smplCnt;
545 //prnt("maxPk: %d",maxPeak);
4d3c1796 546 }
d5051b98 547 peakcnt++;
548 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
549 smplCnt=0;
4d3c1796 550 }
551 }
552 }
d5051b98 553 bool errBitHigh = 0;
554 bool bitHigh = 0;
555 uint8_t ignoreCnt = 0;
556 uint8_t ignoreWindow = 4;
557 bool lastPeakHigh = 0;
558 int lastBit = 0;
559 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
560 peakcnt=0;
561 //test each valid clock from smallest to greatest to see which lines up
562 for(clkCnt=0; clkCnt < 8; ++clkCnt){
563 //ignore clocks smaller than smallest peak
564 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
565 //try lining up the peaks by moving starting point (try first 256)
566 for (ii=20; ii < loopCnt; ++ii){
567 if ((dest[ii] >= peak) || (dest[ii] <= low)){
568 peakcnt = 0;
569 bitHigh = false;
570 ignoreCnt = 0;
571 lastBit = ii-clk[clkCnt];
572 //loop through to see if this start location works
573 for (i = ii; i < size-20; ++i) {
574 //if we are at a clock bit
575 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
576 //test high/low
577 if (dest[i] >= peak || dest[i] <= low) {
578 //if same peak don't count it
579 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
580 peakcnt++;
581 }
582 lastPeakHigh = (dest[i] >= peak);
583 bitHigh = true;
584 errBitHigh = false;
585 ignoreCnt = ignoreWindow;
586 lastBit += clk[clkCnt];
587 } else if (i == lastBit + clk[clkCnt] + tol) {
588 lastBit += clk[clkCnt];
589 }
590 //else if not a clock bit and no peaks
591 } else if (dest[i] < peak && dest[i] > low){
592 if (ignoreCnt==0){
593 bitHigh=false;
594 if (errBitHigh==true) peakcnt--;
595 errBitHigh=false;
596 } else {
597 ignoreCnt--;
598 }
599 // else if not a clock bit but we have a peak
600 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
601 //error bar found no clock...
602 errBitHigh=true;
603 }
604 }
605 if(peakcnt>peaksdet[clkCnt]) {
606 bestStart[clkCnt]=ii;
607 peaksdet[clkCnt]=peakcnt;
608 }
4d3c1796 609 }
4d3c1796 610 }
4d3c1796 611 }
d5051b98 612 int iii=7;
613 uint8_t best=0;
614 for (iii=7; iii > 0; iii--){
615 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
616 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
617 best = iii;
4d3c1796 618 }
d5051b98 619 } else if (peaksdet[iii] > peaksdet[best]){
620 best = iii;
4d3c1796 621 }
d5051b98 622 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);
4d3c1796 623 }
d5051b98 624 *clockStartIdx = bestStart[best];
625 return clk[best];
4d3c1796 626}
d5051b98 627
628int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
629 size_t bestStart=0;
630 return DetectNRZClock_ext(dest, size, clock, &bestStart);
4d3c1796 631}
632
d5051b98 633//by marshmellow
634//countFC is to detect the field clock lengths.
635//counts and returns the 2 most common wave lengths
636//mainly used for FSK field clock detection
637uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) {
638 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
639 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
640 uint8_t fcLensFnd = 0;
641 uint8_t lastFCcnt = 0;
642 uint8_t fcCounter = 0;
643 size_t i;
644 if (size < 180) return 0;
c85858f5 645
d5051b98 646 // prime i to first up transition
647 for (i = 160; i < size-20; i++)
648 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
649 break;
ba1a299c 650
d5051b98 651 for (; i < size-20; i++){
652 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
653 // new up transition
654 fcCounter++;
655 if (fskAdj){
656 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
657 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
658 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
659 if ((fcCounter==9) || fcCounter==4) fcCounter++;
660 // save last field clock count (fc/xx)
661 lastFCcnt = fcCounter;
662 }
663 // find which fcLens to save it to:
664 for (int ii=0; ii<15; ii++){
665 if (fcLens[ii]==fcCounter){
666 fcCnts[ii]++;
667 fcCounter=0;
668 break;
f4eadf8a 669 }
ba1a299c 670 }
d5051b98 671 if (fcCounter>0 && fcLensFnd<15){
672 //add new fc length
673 fcCnts[fcLensFnd]++;
674 fcLens[fcLensFnd++]=fcCounter;
675 }
676 fcCounter=0;
677 } else {
678 // count sample
679 fcCounter++;
ba1a299c 680 }
681 }
d5051b98 682
683 uint8_t best1=14, best2=14, best3=14;
684 uint16_t maxCnt1=0;
685 // go through fclens and find which ones are bigest 2
686 for (i=0; i<15; i++){
687 // get the 3 best FC values
688 if (fcCnts[i]>maxCnt1) {
689 best3=best2;
690 best2=best1;
691 maxCnt1=fcCnts[i];
692 best1=i;
693 } else if(fcCnts[i]>fcCnts[best2]){
694 best3=best2;
695 best2=i;
696 } else if(fcCnts[i]>fcCnts[best3]){
697 best3=i;
698 }
699 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]);
700 }
701 if (fcLens[best1]==0) return 0;
702 uint8_t fcH=0, fcL=0;
703 if (fcLens[best1]>fcLens[best2]){
704 fcH=fcLens[best1];
705 fcL=fcLens[best2];
706 } else{
707 fcH=fcLens[best2];
708 fcL=fcLens[best1];
709 }
710 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
711 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]);
712 return 0; //lots of waves not psk or fsk
713 }
714 // TODO: take top 3 answers and compare to known Field clocks to get top 2
715
716 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
717 if (fskAdj) return fcs;
718 return fcLens[best1];
eb191de6 719}
720
d5051b98 721//by marshmellow
722//detect psk clock by reading each phase shift
723// a phase shift is determined by measuring the sample length of each wave
724int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
725 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
726 uint16_t loopCnt = 4096; //don't need to loop through entire array...
727 if (size == 0) return 0;
728 if (size<loopCnt) loopCnt = size-20;
729
730 //if we already have a valid clock quit
731 size_t i=1;
732 for (; i < 8; ++i)
733 if (clk[i] == clock) return clock;
734
735 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
736 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
737 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
738 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
739 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
740 fc = countFC(dest, size, 0);
741 if (fc!=2 && fc!=4 && fc!=8) return -1;
742 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
743
744 //find first full wave
745 for (i=160; i<loopCnt; i++){
746 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
747 if (waveStart == 0) {
748 waveStart = i+1;
749 //prnt("DEBUG: waveStart: %d",waveStart);
669959bc 750 } else {
d5051b98 751 waveEnd = i+1;
752 //prnt("DEBUG: waveEnd: %d",waveEnd);
753 waveLenCnt = waveEnd-waveStart;
754 if (waveLenCnt > fc){
755 firstFullWave = waveStart;
756 fullWaveLen=waveLenCnt;
757 break;
758 }
759 waveStart=0;
669959bc 760 }
761 }
d5051b98 762 }
763 *firstPhaseShift = firstFullWave;
764 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
765 //test each valid clock from greatest to smallest to see which lines up
766 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
767 lastClkBit = firstFullWave; //set end of wave as clock align
768 waveStart = 0;
769 errCnt=0;
770 peakcnt=0;
771 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
ba1a299c 772
d5051b98 773 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
774 //top edge of wave = start of new wave
775 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
776 if (waveStart == 0) {
777 waveStart = i+1;
778 waveLenCnt=0;
779 } else { //waveEnd
780 waveEnd = i+1;
781 waveLenCnt = waveEnd-waveStart;
782 if (waveLenCnt > fc){
783 //if this wave is a phase shift
784 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);
785 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
786 peakcnt++;
787 lastClkBit+=clk[clkCnt];
788 } else if (i<lastClkBit+8){
789 //noise after a phase shift - ignore
790 } else { //phase shift before supposed to based on clock
791 errCnt++;
792 }
793 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
794 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
795 }
796 waveStart=i+1;
797 }
798 }
13d77ef9 799 }
d5051b98 800 if (errCnt == 0){
801 return clk[clkCnt];
802 }
803 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
804 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
805 }
806 //all tested with errors
807 //return the highest clk with the most peaks found
808 uint8_t best=7;
809 for (i=7; i>=1; i--){
810 if (peaksdet[i] > peaksdet[best]) {
811 best = i;
812 }
813 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
13d77ef9 814 }
d5051b98 815 return clk[best];
eb191de6 816}
6fe5c94b 817
d5051b98 818int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
819 int firstPhaseShift = 0;
820 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
eb191de6 821}
a1d17964 822
d5051b98 823//by marshmellow
824//detects the bit clock for FSK given the high and low Field Clocks
825uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
826 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
827 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
828 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
829 uint8_t rfLensFnd = 0;
830 uint8_t lastFCcnt = 0;
831 uint16_t fcCounter = 0;
832 uint16_t rfCounter = 0;
833 uint8_t firstBitFnd = 0;
834 size_t i;
835 if (size == 0) return 0;
669959bc 836
d5051b98 837 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
838 rfLensFnd=0;
839 fcCounter=0;
840 rfCounter=0;
841 firstBitFnd=0;
842 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
843 // prime i to first peak / up transition
844 for (i = 160; i < size-20; i++)
845 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
846 break;
847
848 for (; i < size-20; i++){
849 fcCounter++;
850 rfCounter++;
851
852 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
853 continue;
854 // else new peak
855 // if we got less than the small fc + tolerance then set it to the small fc
856 // if it is inbetween set it to the last counter
857 if (fcCounter < fcHigh && fcCounter > fcLow)
858 fcCounter = lastFCcnt;
859 else if (fcCounter < fcLow+fcTol)
860 fcCounter = fcLow;
861 else //set it to the large fc
862 fcCounter = fcHigh;
863
864 //look for bit clock (rf/xx)
865 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
866 //not the same size as the last wave - start of new bit sequence
867 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
868 for (int ii=0; ii<15; ii++){
869 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
870 rfCnts[ii]++;
871 rfCounter = 0;
872 break;
873 }
874 }
875 if (rfCounter > 0 && rfLensFnd < 15){
876 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
877 rfCnts[rfLensFnd]++;
878 rfLens[rfLensFnd++] = rfCounter;
879 }
880 } else {
881 *firstClockEdge = i;
882 firstBitFnd++;
883 }
884 rfCounter=0;
885 lastFCcnt=fcCounter;
e0165dcf 886 }
d5051b98 887 fcCounter=0;
e0165dcf 888 }
d5051b98 889 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
890
891 for (i=0; i<15; i++){
892 //get highest 2 RF values (might need to get more values to compare or compare all?)
893 if (rfCnts[i]>rfCnts[rfHighest]){
894 rfHighest3=rfHighest2;
895 rfHighest2=rfHighest;
896 rfHighest=i;
897 } else if(rfCnts[i]>rfCnts[rfHighest2]){
898 rfHighest3=rfHighest2;
899 rfHighest2=i;
900 } else if(rfCnts[i]>rfCnts[rfHighest3]){
901 rfHighest3=i;
902 }
903 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
904 }
905 // set allowed clock remainder tolerance to be 1 large field clock length+1
906 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
907 uint8_t tol1 = fcHigh+1;
908
909 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
eb191de6 910
d5051b98 911 // loop to find the highest clock that has a remainder less than the tolerance
912 // compare samples counted divided by
913 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
914 int ii=7;
915 for (; ii>=2; ii--){
916 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
917 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
918 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
919 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
920 break;
921 }
922 }
4d3c1796 923 }
ec75f5c1 924 }
ec75f5c1 925
d5051b98 926 if (ii<2) return 0; // oops we went too far
eb191de6 927
d5051b98 928 return clk[ii];
929}
415274a7 930
d5051b98 931uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
932 int firstClockEdge = 0;
933 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
934}
415274a7 935
d5051b98 936//**********************************************************************************************
937//--------------------Modulation Demods &/or Decoding Section-----------------------------------
938//**********************************************************************************************
1e090a61 939
d5051b98 940// 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...
549daaf7 941bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, int *i) {
942 for (; *i < buffSize - 4; *i+=1) {
943 *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...
944 if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
945 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
946 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
947 if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
948 *stStopLoc = *i + 3;
d5051b98 949 return true;
4d3c1796 950 }
4d3c1796 951 }
4d3c1796 952 }
953 }
4d3c1796 954 }
d5051b98 955 return false;
6923d3f1 956}
d5051b98 957//by marshmellow
958//attempt to identify a Sequence Terminator in ASK modulated raw wave
959bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
960 size_t bufsize = *size;
961 //need to loop through all samples and identify our clock, look for the ST pattern
4d3c1796 962 uint8_t fndClk[] = {8,16,32,40,50,64,128};
d5051b98 963 int clk = 0;
964 int tol = 0;
c83d6dc6 965 int i=0, j, skip, start, end, low, high, minClk=255;
d5051b98 966 //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
967 int tmpbuff[bufsize / 32]; // 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
968 int waveLen[bufsize / 32]; // high to low wave count //if clock is larger then we waste memory in array size that is not needed...
c83d6dc6 969 //size_t testsize = (bufsize < 512) ? bufsize : 512;
d5051b98 970 int phaseoff = 0;
971 high = low = 128;
972 memset(tmpbuff, 0, sizeof(tmpbuff));
549daaf7 973 memset(waveLen, 0, sizeof(waveLen));
d5051b98 974
c83d6dc6 975 if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
d5051b98 976 // set clock - might be able to get this externally and remove this work...
977 if (!clk) {
978 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
979 tol = fndClk[clkCnt]/8;
980 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
981 clk=fndClk[clkCnt];
982 break;
e0165dcf 983 }
984 }
d5051b98 985 // clock not found - ERROR
986 if (!clk) {
987 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
988 return false;
989 }
990 } else tol = clk/8;
6e984446 991
d5051b98 992 *foundclock = clk;
549daaf7 993 if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
d5051b98 994 // first ST not found - ERROR
995 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
996 return false;
997 } else {
549daaf7 998 if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
cc15a118 999 }
d5051b98 1000 if (waveLen[i+2] > clk*1+tol)
1001 phaseoff = 0;
1002 else
1003 phaseoff = clk/2;
1004
1005 // skip over the remainder of ST
1006 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
2eec55c8 1007
d5051b98 1008 // now do it again to find the end
1009 int dummy1 = 0;
1010 end = skip;
549daaf7 1011 i+=3;
1012 if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
d5051b98 1013 //didn't find second ST - ERROR
1014 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1015 return false;
1016 }
1017 end -= phaseoff;
1018 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);
1019 //now begin to trim out ST so we can use normal demod cmds
1020 start = skip;
1021 size_t datalen = end - start;
1022 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1023 if ( clk - (datalen % clk) <= clk/8) {
1024 // padd the amount off - could be problematic... but shouldn't happen often
1025 datalen += clk - (datalen % clk);
1026 } else if ( (datalen % clk) <= clk/8 ) {
1027 // padd the amount off - could be problematic... but shouldn't happen often
1028 datalen -= datalen % clk;
1029 } else {
1030 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1031 return false;
1032 }
1033 // if datalen is less than one t55xx block - ERROR
1034 if (datalen/clk < 8*4) {
1035 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1036 return false;
1037 }
1038 size_t dataloc = start;
1039 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1040 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1041 for ( i=0; i <= (clk/8); ++i ) {
1042 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1043 dataloc -= i;
1044 break;
2eec55c8 1045 }
e0165dcf 1046 }
1047 }
d5051b98 1048
1049 size_t newloc = 0;
1050 i=0;
1051 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1052 bool firstrun = true;
1053 // warning - overwriting buffer given with raw wave data with ST removed...
1054 while ( dataloc < bufsize-(clk/2) ) {
1055 //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)
1056 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1057 for(i=0; i < clk/2-tol; ++i) {
1058 buffer[dataloc+i] = high+5;
1059 }
1060 } //test for single sample outlier (high between two lows) in the case of very strong waves
1061 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1062 buffer[dataloc] = buffer[dataloc+2];
1063 buffer[dataloc+1] = buffer[dataloc+2];
1064 }
1065 if (firstrun) {
1066 *stend = dataloc;
1067 *ststart = dataloc-(clk*4);
1068 firstrun=false;
1069 }
1070 for (i=0; i<datalen; ++i) {
1071 if (i+newloc < bufsize) {
1072 if (i+newloc < dataloc)
1073 buffer[i+newloc] = buffer[dataloc];
1074
1075 dataloc++;
e0165dcf 1076 }
1077 }
d5051b98 1078 newloc += i;
1079 //skip next ST - we just assume it will be there from now on...
1080 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1081 dataloc += clk*4;
e0165dcf 1082 }
d5051b98 1083 *size = newloc;
1084 return true;
1085}
1086bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1087 size_t ststart = 0, stend = 0;
1088 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
eb191de6 1089}
ba1a299c 1090
549daaf7 1091//by marshmellow
127f1490 1092//take 11 10 01 11 00 and make 01100 ... miller decoding
549daaf7 1093//check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
1094//decodes miller encoded binary
1095//NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
127f1490 1096int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
549daaf7 1097 if (*size < 16) return -1;
127f1490 1098 uint16_t MaxBits = 512, errCnt = 0;
1099 size_t i, bitCnt=0;
1100 uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
1101 uint8_t halfClkErr = 0;
549daaf7 1102 //find alignment, needs 4 1s or 0s to properly align
127f1490 1103 for (i=1; i < *size-1; i++) {
549daaf7 1104 alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
1105 curBit = BitStream[i];
1106 if (alignCnt == 4) break;
1107 }
1108 // for now error if alignment not found. later add option to run it with multiple offsets...
1109 if (alignCnt != 4) {
1110 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");
1111 return -1;
1112 }
127f1490 1113 alignedIdx = (i-1) % 2;
1114 for (i=alignedIdx; i < *size-3; i+=2) {
1115 halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
1116 if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
1117 errCnt++;
1118 BitStream[bitCnt++] = 7;
1119 continue;
1120 }
1121 BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
549daaf7 1122
127f1490 1123 if (bitCnt > MaxBits) break;
1124 }
1125 *size = bitCnt;
1126 return errCnt;
1127}
549daaf7 1128
d5051b98 1129//by marshmellow
1130//take 01 or 10 = 1 and 11 or 00 = 0
1131//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
1132//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1133int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) {
1134 uint16_t bitnum = 0;
1135 uint16_t errCnt = 0;
1136 size_t i = offset;
1137 uint16_t MaxBits=512;
1138 //if not enough samples - error
1139 if (*size < 51) return -1;
1140 //check for phase change faults - skip one sample if faulty
1141 uint8_t offsetA = 1, offsetB = 1;
1142 for (; i<48; i+=2){
1143 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
1144 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
1145 }
1146 if (!offsetA && offsetB) offset++;
1147 for (i=offset; i<*size-3; i+=2){
1148 //check for phase error
1149 if (BitStream[i+1]==BitStream[i+2]) {
1150 BitStream[bitnum++]=7;
1151 errCnt++;
1152 }
1153 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1154 BitStream[bitnum++]=1^invert;
1155 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1156 BitStream[bitnum++]=invert;
1157 } else {
1158 BitStream[bitnum++]=7;
1159 errCnt++;
db829602 1160 }
d5051b98 1161 if(bitnum>MaxBits) break;
db829602 1162 }
d5051b98 1163 *size=bitnum;
1164 return errCnt;
db829602 1165}
1166
6de43508 1167//by marshmellow
d5051b98 1168//take 10 and 01 and manchester decode
1169//run through 2 times and take least errCnt
1170int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) {
1171 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
1172 size_t i, ii;
1173 uint16_t bestErr = 1000, bestRun = 0;
1174 if (*size < 16) return -1;
1175 //find correct start position [alignment]
1176 for (ii=0;ii<2;++ii){
1177 for (i=ii; i<*size-3; i+=2)
1178 if (BitStream[i]==BitStream[i+1])
1179 errCnt++;
1180
1181 if (bestErr>errCnt){
1182 bestErr=errCnt;
1183 bestRun=ii;
1184 }
1185 errCnt=0;
1186 }
1187 *alignPos=bestRun;
1188 //decode
1189 for (i=bestRun; i < *size-3; i+=2){
1190 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
1191 BitStream[bitnum++]=invert;
1192 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
1193 BitStream[bitnum++]=invert^1;
e0165dcf 1194 } else {
d5051b98 1195 BitStream[bitnum++]=7;
e0165dcf 1196 }
d5051b98 1197 if(bitnum>MaxBits) break;
e0165dcf 1198 }
d5051b98 1199 *size=bitnum;
1200 return bestErr;
1201}
1202
1203//by marshmellow
1204//demodulates strong heavily clipped samples
1205int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
1206{
1207 *startIdx=0;
1208 size_t bitCnt=0, smplCnt=1, errCnt=0;
1209 bool waveHigh = (BinStream[0] >= high);
1210 for (size_t i=1; i < *size; i++){
1211 if (BinStream[i] >= high && waveHigh){
1212 smplCnt++;
1213 } else if (BinStream[i] <= low && !waveHigh){
1214 smplCnt++;
1215 } else { //transition
1216 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
1217 if (smplCnt > clk-(clk/4)-1) { //full clock
1218 if (smplCnt > clk + (clk/4)+1) { //too many samples
1219 errCnt++;
1220 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1221 BinStream[bitCnt++] = 7;
1222 } else if (waveHigh) {
1223 BinStream[bitCnt++] = invert;
1224 BinStream[bitCnt++] = invert;
1225 } else if (!waveHigh) {
1226 BinStream[bitCnt++] = invert ^ 1;
1227 BinStream[bitCnt++] = invert ^ 1;
e0165dcf 1228 }
d5051b98 1229 if (*startIdx==0) *startIdx = i-clk;
1230 waveHigh = !waveHigh;
1231 smplCnt = 0;
1232 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
1233 if (waveHigh) {
1234 BinStream[bitCnt++] = invert;
1235 } else if (!waveHigh) {
1236 BinStream[bitCnt++] = invert ^ 1;
1237 }
1238 if (*startIdx==0) *startIdx = i-(clk/2);
1239 waveHigh = !waveHigh;
1240 smplCnt = 0;
1241 } else {
1242 smplCnt++;
1243 //transition bit oops
e0165dcf 1244 }
d5051b98 1245 } else { //haven't hit new high or new low yet
1246 smplCnt++;
db829602 1247 }
e0165dcf 1248 }
e0165dcf 1249 }
d5051b98 1250 *size = bitCnt;
1251 return errCnt;
669959bc 1252}
1253
4d3c1796 1254//by marshmellow
d5051b98 1255//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
1256int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
1257 if (*size==0) return -1;
1258 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
1259 if (*clk==0 || start < 0) return -3;
1260 if (*invert != 1) *invert = 0;
1261 if (amp==1) askAmp(BinStream, *size);
1262 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
4d3c1796 1263
d5051b98 1264 //start pos from detect ask clock is 1/2 clock offset
1265 // NOTE: can be negative (demod assumes rest of wave was there)
1266 *startIdx = start - (*clk/2);
1267 uint8_t initLoopMax = 255;
1268 if (initLoopMax > *size) initLoopMax = *size;
1269 // Detect high and lows
1270 //25% clip in case highs and lows aren't clipped [marshmellow]
1271 int high, low;
1272 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
1273 return -2; //just noise
4d3c1796 1274
d5051b98 1275 size_t errCnt = 0;
1276 // if clean clipped waves detected run alternate demod
1277 if (DetectCleanAskWave(BinStream, *size, high, low)) {
1278 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
1279 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
1280 if (askType) { //askman
1281 uint8_t alignPos = 0;
1282 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
1283 *startIdx += *clk/2 * alignPos;
1284 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
1285 return errCnt;
1286 } else { //askraw
1287 return errCnt;
1288 }
1289 }
1290 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
1291 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
1292
1293 int lastBit; //set first clock check - can go negative
1294 size_t i, bitnum = 0; //output counter
1295 uint8_t midBit = 0;
1296 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
1297 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
1298 size_t MaxBits = 3072; //max bits to collect
1299 lastBit = start - *clk;
1300
1301 for (i = start; i < *size; ++i) {
1302 if (i-lastBit >= *clk-tol){
1303 if (BinStream[i] >= high) {
1304 BinStream[bitnum++] = *invert;
1305 } else if (BinStream[i] <= low) {
1306 BinStream[bitnum++] = *invert ^ 1;
1307 } else if (i-lastBit >= *clk+tol) {
1308 if (bitnum > 0) {
1309 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1310 BinStream[bitnum++]=7;
1311 errCnt++;
1312 }
1313 } else { //in tolerance - looking for peak
1314 continue;
4d3c1796 1315 }
d5051b98 1316 midBit = 0;
1317 lastBit += *clk;
1318 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
1319 if (BinStream[i] >= high) {
1320 BinStream[bitnum++] = *invert;
1321 } else if (BinStream[i] <= low) {
1322 BinStream[bitnum++] = *invert ^ 1;
1323 } else if (i-lastBit >= *clk/2+tol) {
1324 BinStream[bitnum] = BinStream[bitnum-1];
1325 bitnum++;
1326 } else { //in tolerance - looking for peak
1327 continue;
4d3c1796 1328 }
d5051b98 1329 midBit = 1;
04d2721b 1330 }
d5051b98 1331 if (bitnum >= MaxBits) break;
04d2721b 1332 }
d5051b98 1333 *size = bitnum;
1334 return errCnt;
1335}
1336
1337int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
1338 int start = 0;
1339 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
1340}
1341
1342// by marshmellow - demodulate NRZ wave - requires a read with strong signal
1343// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1344int nrzRawDemod_ext(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1345 if (justNoise(dest, *size)) return -1;
1346 *clk = DetectNRZClock(dest, *size, *clk);
1347 if (*clk==0) return -2;
1348 size_t i, gLen = 4096;
1349 if (gLen>*size) gLen = *size-20;
1350 int high, low;
1351 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
4d3c1796 1352
d5051b98 1353 uint8_t bit=0;
1354 //convert wave samples to 1's and 0's
1355 for(i=20; i < *size-20; i++){
1356 if (dest[i] >= high) bit = 1;
1357 if (dest[i] <= low) bit = 0;
1358 dest[i] = bit;
4d3c1796 1359 }
d5051b98 1360 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1361 size_t lastBit = 0;
1362 size_t numBits = 0;
1363 for(i=21; i < *size-20; i++) {
1364 //if transition detected or large number of same bits - store the passed bits
1365 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1366 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1367 numBits += (i - lastBit + (*clk/4)) / *clk;
1368 if (lastBit == 0) {
1369 *startIdx = i - (numBits * *clk);
1370 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1371 }
1372 lastBit = i-1;
1373 }
4d3c1796 1374 }
d5051b98 1375 *size = numBits;
1376 return 0;
1377}
1378int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) {
1379 int startIdx = 0;
1380 return nrzRawDemod_ext(dest, size, clk, invert, &startIdx);
3bc66a96 1381}
1382
d5051b98 1383//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
1384size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1385 size_t last_transition = 0;
1386 size_t idx = 1;
1387 if (fchigh==0) fchigh=10;
1388 if (fclow==0) fclow=8;
1389 //set the threshold close to 0 (graph) or 128 std to avoid static
1390 uint8_t threshold_value = 123;
1391 size_t preLastSample = 0;
1392 size_t LastSample = 0;
1393 size_t currSample = 0;
1394 if ( size < 1024 ) return 0; // not enough samples
ba1a299c 1395
d5051b98 1396 //find start of modulating data in trace
1397 idx = findModStart(dest, size, threshold_value, fchigh);
1398 // Need to threshold first sample
1399 if(dest[idx] < threshold_value) dest[0] = 0;
1400 else dest[0] = 1;
1401
1402 last_transition = idx;
1403 idx++;
1404 size_t numBits = 0;
1405 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
1406 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
1407 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
1408 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
1409 for(; idx < size; idx++) {
1410 // threshold current value
1411 if (dest[idx] < threshold_value) dest[idx] = 0;
1412 else dest[idx] = 1;
4d3c1796 1413
d5051b98 1414 // Check for 0->1 transition
1415 if (dest[idx-1] < dest[idx]) {
1416 preLastSample = LastSample;
1417 LastSample = currSample;
1418 currSample = idx-last_transition;
1419 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
1420 //do nothing with extra garbage
1421 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
1422 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
1423 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
1424 dest[numBits-1]=1;
1425 }
1426 dest[numBits++]=1;
1427 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1428 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
1429 //do nothing with beginning garbage and reset.. should be rare..
1430 numBits = 0;
1431 } 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)
1432 dest[numBits++]=1;
1433 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1434 } else { //9+ = 10 sample waves (or 6+ = 7)
1435 dest[numBits++]=0;
1436 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
4d3c1796 1437 }
d5051b98 1438 last_transition = idx;
4d3c1796 1439 }
e0165dcf 1440 }
d5051b98 1441 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
1442}
4d3c1796 1443
d5051b98 1444//translate 11111100000 to 10
1445//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
1446size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1447 uint8_t lastval=dest[0];
1448 size_t idx=0;
1449 size_t numBits=0;
1450 uint32_t n=1;
1451 for( idx=1; idx < size; idx++) {
1452 n++;
1453 if (dest[idx]==lastval) continue; //skip until we hit a transition
1454
1455 //find out how many bits (n) we collected (use 1/2 clk tolerance)
1456 //if lastval was 1, we have a 1->0 crossing
1457 if (dest[idx-1]==1) {
1458 n = (n * fclow + rfLen/2) / rfLen;
1459 } else {// 0->1 crossing
1460 n = (n * fchigh + rfLen/2) / rfLen;
e0165dcf 1461 }
d5051b98 1462 if (n == 0) n = 1;
1463
1464 //first transition - save startidx
1465 if (numBits == 0) {
1466 if (lastval == 1) { //high to low
1467 *startIdx += (fclow * idx) - (n*rfLen);
1468 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
1469 } else {
1470 *startIdx += (fchigh * idx) - (n*rfLen);
1471 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
1472 }
4d3c1796 1473 }
d5051b98 1474
1475 //add to our destination the bits we collected
1476 memset(dest+numBits, dest[idx-1]^invert , n);
1477 numBits += n;
1478 n=0;
1479 lastval=dest[idx];
1480 }//end for
1481 // if valid extra bits at the end were all the same frequency - add them in
1482 if (n > rfLen/fchigh) {
1483 if (dest[idx-2]==1) {
1484 n = (n * fclow + rfLen/2) / rfLen;
1485 } else {
1486 n = (n * fchigh + rfLen/2) / rfLen;
4d3c1796 1487 }
d5051b98 1488 memset(dest+numBits, dest[idx-1]^invert , n);
1489 numBits += n;
e0165dcf 1490 }
d5051b98 1491 return numBits;
ba1a299c 1492}
4d3c1796 1493
d5051b98 1494//by marshmellow (from holiman's base)
1495// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
1496int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1497 // FSK demodulator
1498 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
1499 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
1500 return size;
8b6abef5 1501}
1502
d5051b98 1503int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
1504 int startIdx=0;
1505 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
1506}
e0165dcf 1507
d5051b98 1508// by marshmellow
1509// convert psk1 demod to psk2 demod
1510// only transition waves are 1s
1511void psk1TOpsk2(uint8_t *BitStream, size_t size) {
1512 size_t i=1;
1513 uint8_t lastBit=BitStream[0];
1514 for (; i<size; i++){
1515 if (BitStream[i]==7){
1516 //ignore errors
1517 } else if (lastBit!=BitStream[i]){
1518 lastBit=BitStream[i];
1519 BitStream[i]=1;
1520 } else {
1521 BitStream[i]=0;
1522 }
1523 }
1524 return;
1525}
e0165dcf 1526
d5051b98 1527// by marshmellow
1528// convert psk2 demod to psk1 demod
1529// from only transition waves are 1s to phase shifts change bit
1530void psk2TOpsk1(uint8_t *BitStream, size_t size) {
1531 uint8_t phase=0;
1532 for (size_t i=0; i<size; i++){
1533 if (BitStream[i]==1){
1534 phase ^=1;
1535 }
1536 BitStream[i]=phase;
1537 }
1538 return;
1539}
2eec55c8 1540
d5051b98 1541//by marshmellow - demodulate PSK1 wave
1542//uses wave lengths (# Samples)
1543int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1544 if (size == 0) return -1;
1545 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1546 if (*size<loopCnt) loopCnt = *size;
2eec55c8 1547
d5051b98 1548 size_t numBits=0;
1549 uint8_t curPhase = *invert;
1550 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1551 uint16_t fc=0, fullWaveLen=0, tol=1;
1552 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1553 fc = countFC(dest, *size, 1);
1554 uint8_t fc2 = fc >> 8;
1555 if (fc2 == 10) return -1; //fsk found - quit
1556 fc = fc & 0xFF;
1557 if (fc!=2 && fc!=4 && fc!=8) return -1;
1558 //PrintAndLog("DEBUG: FC: %d",fc);
1559 *clock = DetectPSKClock(dest, *size, *clock);
1560 if (*clock == 0) return -1;
1561
1562 //find start of modulating data in trace
1563 uint8_t threshold_value = 123; //-5
1564 i = findModStart(dest, *size, threshold_value, fc);
1565
1566 //find first phase shift
1567 int avgWaveVal=0, lastAvgWaveVal=0;
1568 waveStart = i;
1569 for (; i<loopCnt; i++) {
1570 // find peak
1571 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1572 waveEnd = i+1;
1573 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1574 waveLenCnt = waveEnd-waveStart;
1575 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1576 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1577 firstFullWave = waveStart;
1578 fullWaveLen=waveLenCnt;
1579 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1580 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
1581 break;
e0165dcf 1582 }
e0165dcf 1583
d5051b98 1584 waveStart = i+1;
1585 avgWaveVal = 0;
e0165dcf 1586 }
d5051b98 1587 avgWaveVal += dest[i+2];
1588 }
1589 if (firstFullWave == 0) {
1590 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1591 // so skip a little to ensure we are past any Start Signal
1592 firstFullWave = 160;
1593 memset(dest, curPhase, firstFullWave / *clock);
1594 } else {
1595 memset(dest, curPhase^1, firstFullWave / *clock);
1596 }
1597 //advance bits
1598 numBits += (firstFullWave / *clock);
1599 *startIdx = firstFullWave - (*clock * numBits)+2;
1600 //set start of wave as clock align
1601 lastClkBit = firstFullWave;
1602 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1603 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1604 waveStart = 0;
1605 dest[numBits++] = curPhase; //set first read bit
1606 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1607 //top edge of wave = start of new wave
1608 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1609 if (waveStart == 0) {
1610 waveStart = i+1;
1611 waveLenCnt = 0;
1612 avgWaveVal = dest[i+1];
1613 } else { //waveEnd
1614 waveEnd = i+1;
1615 waveLenCnt = waveEnd-waveStart;
1616 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1617 if (waveLenCnt > fc){
1618 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1619 //this wave is a phase shift
1620 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1621 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1622 curPhase ^= 1;
1623 dest[numBits++] = curPhase;
1624 lastClkBit += *clock;
1625 } else if (i < lastClkBit+10+fc){
1626 //noise after a phase shift - ignore
1627 } else { //phase shift before supposed to based on clock
1628 errCnt++;
1629 dest[numBits++] = 7;
1630 }
1631 } else if (i+1 > lastClkBit + *clock + tol + fc){
1632 lastClkBit += *clock; //no phase shift but clock bit
1633 dest[numBits++] = curPhase;
1634 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1635 errCnt2++;
1636 if(errCnt2 > 101) return errCnt2;
e0165dcf 1637 }
d5051b98 1638 avgWaveVal = 0;
1639 waveStart = i+1;
e0165dcf 1640 }
1641 }
d5051b98 1642 avgWaveVal += dest[i+1];
e0165dcf 1643 }
d5051b98 1644 *size = numBits;
1645 return errCnt;
03e6bb4a 1646}
1e090a61 1647
d5051b98 1648int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1649 int startIdx = 0;
1650 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
669959bc 1651}
1652
d5051b98 1653//**********************************************************************************************
1654//-----------------Tag format detection section-------------------------------------------------
1655//**********************************************************************************************
4d3c1796 1656
1657// by marshmellow
1658// FSK Demod then try to locate an AWID ID
1659int AWIDdemodFSK(uint8_t *dest, size_t *size) {
1660 //make sure buffer has enough data
1661 if (*size < 96*50) return -1;
1662
1663 if (justNoise(dest, *size)) return -2;
1664
1665 // FSK demodulator
1666 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1667 if (*size < 96) return -3; //did we get a good demod?
1668
1669 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
1670 size_t startIdx = 0;
1671 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1672 if (errChk == 0) return -4; //preamble not found
1673 if (*size != 96) return -5;
1674 return (int)startIdx;
1675}
1676
03e6bb4a 1677//by marshmellow
4d3c1796 1678//takes 1s and 0s and searches for EM410x format - output EM ID
1679uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
03e6bb4a 1680{
4d3c1796 1681 //sanity checks
1682 if (*size < 64) return 0;
1683 if (BitStream[1]>1) return 0; //allow only 1s and 0s
e0165dcf 1684
4d3c1796 1685 // 111111111 bit pattern represent start of frame
1686 // include 0 in front to help get start pos
1687 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
1688 uint8_t errChk = 0;
1689 uint8_t FmtLen = 10; // sets of 4 bits = end data
1690 *startIdx = 0;
1691 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
1692 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
1693 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
e0165dcf 1694
4d3c1796 1695 //skip last 4bit parity row for simplicity
1696 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
1697 if (*size == 40) { // std em410x format
1698 *hi = 0;
1699 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
1700 } else if (*size == 88) { // long em format
1701 *hi = (bytebits_to_byte(BitStream, 24));
1702 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
1703 } else {
1704 return 0;
709665b5 1705 }
4d3c1796 1706 return 1;
6de43508 1707}
1708
4d3c1796 1709// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
1710// BitStream must contain previously askrawdemod and biphasedemoded data
1711int FDXBdemodBI(uint8_t *dest, size_t *size) {
1712 //make sure buffer has enough data
1713 if (*size < 128) return -1;
e0165dcf 1714
4d3c1796 1715 size_t startIdx = 0;
1716 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
6980d66b 1717
4d3c1796 1718 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1719 if (errChk == 0) return -2; //preamble not found
1720 return (int)startIdx;
1721}
6980d66b 1722
4d3c1796 1723// by marshmellow
1724// demod gProxIIDemod
1725// error returns as -x
1726// success returns start position in BitStream
1727// BitStream must contain previously askrawdemod and biphasedemoded data
1728int gProxII_Demod(uint8_t BitStream[], size_t *size) {
1729 size_t startIdx=0;
1730 uint8_t preamble[] = {1,1,1,1,1,0};
669959bc 1731
4d3c1796 1732 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
1733 if (errChk == 0) return -3; //preamble not found
1734 if (*size != 96) return -2; //should have found 96 bits
1735 //check first 6 spacer bits to verify format
1736 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
1737 //confirmed proper separator bits found
1738 //return start position
1739 return (int) startIdx;
e0165dcf 1740 }
4d3c1796 1741 return -5; //spacer bits not found - not a valid gproxII
ab812dfa 1742}
1743
4d3c1796 1744// loop to get raw HID waveform then FSK demodulate the TAG ID from it
1745int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1746 if (justNoise(dest, *size)) return -1;
d1869c33 1747
4d3c1796 1748 size_t numStart=0, size2=*size, startIdx=0;
1749 // FSK demodulator
1750 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1751 if (*size < 96*2) return -2;
1752 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1753 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
1754 // find bitstring in array
1755 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1756 if (errChk == 0) return -3; //preamble not found
d1869c33 1757
4d3c1796 1758 numStart = startIdx + sizeof(preamble);
1759 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1760 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1761 if (dest[idx] == dest[idx+1]){
1762 return -4; //not manchester data
d1869c33 1763 }
4d3c1796 1764 *hi2 = (*hi2<<1)|(*hi>>31);
1765 *hi = (*hi<<1)|(*lo>>31);
1766 //Then, shift in a 0 or one into low
1767 if (dest[idx] && !dest[idx+1]) // 1 0
1768 *lo=(*lo<<1)|1;
1769 else // 0 1
1770 *lo=(*lo<<1)|0;
d1869c33 1771 }
4d3c1796 1772 return (int)startIdx;
1773}
d1869c33 1774
4d3c1796 1775int IOdemodFSK(uint8_t *dest, size_t size) {
1776 if (justNoise(dest, size)) return -1;
1777 //make sure buffer has data
1778 if (size < 66*64) return -2;
1779 // FSK demodulator
1780 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
1781 if (size < 65) return -3; //did we get a good demod?
1782 //Index map
1783 //0 10 20 30 40 50 60
1784 //| | | | | | |
1785 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
1786 //-----------------------------------------------------------------------------
1787 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
1788 //
1789 //XSF(version)facility:codeone+codetwo
1790 //Handle the data
1791 size_t startIdx = 0;
1792 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
1793 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
1794 if (errChk == 0) return -4; //preamble not found
d1869c33 1795
4d3c1796 1796 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
1797 //confirmed proper separator bits found
1798 //return start position
1799 return (int) startIdx;
d1869c33 1800 }
4d3c1796 1801 return -5;
1802}
d1869c33 1803
4d3c1796 1804// redesigned by marshmellow adjusted from existing decode functions
1805// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1806int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1807 //26 bit 40134 format (don't know other formats)
1808 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};
1809 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};
1810 size_t startidx = 0;
1811 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1812 // if didn't find preamble try again inverting
1813 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1814 *invert ^= 1;
1815 }
1816 if (*size != 64 && *size != 224) return -2;
1817 if (*invert==1)
1818 for (size_t i = startidx; i < *size; i++)
1819 bitStream[i] ^= 1;
1820
1821 return (int) startidx;
1822}
1823
1824// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
1825int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1826 if (justNoise(dest, *size)) return -1;
01d0f8ae 1827
4d3c1796 1828 size_t numStart=0, size2=*size, startIdx=0;
1829 // FSK demodulator
1830 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1831 if (*size < 96) return -2;
d1869c33 1832
4d3c1796 1833 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1834 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
1835
1836 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1837 if (errChk == 0) return -3; //preamble not found
1838
1839 numStart = startIdx + sizeof(preamble);
1840 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1841 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1842 if (dest[idx] == dest[idx+1])
1843 return -4; //not manchester data
1844 *hi2 = (*hi2<<1)|(*hi>>31);
1845 *hi = (*hi<<1)|(*lo>>31);
1846 //Then, shift in a 0 or one into low
1847 if (dest[idx] && !dest[idx+1]) // 1 0
1848 *lo=(*lo<<1)|1;
1849 else // 0 1
1850 *lo=(*lo<<1)|0;
d1869c33 1851 }
4d3c1796 1852 return (int)startIdx;
d1869c33 1853}
8b6abef5 1854
4d3c1796 1855// find presco preamble 0x10D in already demoded data
1856int PrescoDemod(uint8_t *dest, size_t *size) {
1857 //make sure buffer has data
1858 if (*size < 64*2) return -2;
1859
1860 size_t startIdx = 0;
1861 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
1862 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1863 if (errChk == 0) return -4; //preamble not found
1864 //return start position
1865 return (int) startIdx;
669959bc 1866}
1867
4d3c1796 1868// by marshmellow
1869// FSK Demod then try to locate a Farpointe Data (pyramid) ID
1870int PyramiddemodFSK(uint8_t *dest, size_t *size) {
1871 //make sure buffer has data
1872 if (*size < 128*50) return -5;
1873
1874 //test samples are not just noise
1875 if (justNoise(dest, *size)) return -1;
1876
1877 // FSK demodulator
1878 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1879 if (*size < 128) return -2; //did we get a good demod?
1880
1881 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
1882 size_t startIdx = 0;
1883 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1884 if (errChk == 0) return -4; //preamble not found
1885 if (*size != 128) return -3;
1886 return (int)startIdx;
1887}
1888
1889// by marshmellow
1890// find viking preamble 0xF200 in already demoded data
1891int VikingDemod_AM(uint8_t *dest, size_t *size) {
1892 //make sure buffer has data
1893 if (*size < 64*2) return -2;
1894
1895 size_t startIdx = 0;
1896 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};
1897 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1898 if (errChk == 0) return -4; //preamble not found
1899 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
1900 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
1901 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
1902 if ( checkCalc != 0xA8 ) return -5;
1903 if (*size != 64) return -6;
1904 //return start position
1905 return (int) startIdx;
1906}
1907
8b6abef5 1908// by iceman
1909// find Visa2000 preamble in already demoded data
1910int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1911 if (*size < 96) return -1; //make sure buffer has data
1912 size_t startIdx = 0;
1913 uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0};
1914 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1915 return -2; //preamble not found
1916 if (*size != 96) return -3; //wrong demoded size
1917 //return start position
1918 return (int)startIdx;
1919}
Impressum, Datenschutz