d6ef88a40280e57d3e241baffc772bfd70e1aeed
[proxmark3-svn] / common / lfdemod.c
1 //-----------------------------------------------------------------------------
2 // Copyright (C) 2014
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 //-----------------------------------------------------------------------------
8 // Low frequency demod/decode commands - by marshmellow, holiman, iceman and
9 // many others who came before
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 //
19 // we tried to include author comments so any questions could be directed to
20 // the source.
21 //
22 // There are 4 main sections of code below:
23 // Utilities Section:
24 // for general utilities used by multiple other functions
25 // Clock / Bitrate Detection Section:
26 // for clock detection functions for each modulation
27 // Modulation Demods &/or Decoding Section:
28 // for main general modulation demodulating and encoding decoding code.
29 // Tag format detection section:
30 // for detection of specific tag formats within demodulated data
31 //
32 // marshmellow
33 //-----------------------------------------------------------------------------
34
35 #include <string.h> // for memset, memcmp and size_t
36 #include "lfdemod.h"
37 #include <stdint.h> // for uint_32+
38 #include <stdbool.h> // for bool
39 #include "parity.h" // for parity test
40
41 //**********************************************************************************************
42 //---------------------------------Utilities Section--------------------------------------------
43 //**********************************************************************************************
44 #define LOWEST_DEFAULT_CLOCK 32
45 #define FSK_PSK_THRESHOLD 123
46
47 //to allow debug print calls when used not on device
48 void dummy(char *fmt, ...){}
49 #ifndef ON_DEVICE
50 #include "ui.h"
51 #include "cmdparser.h"
52 #include "cmddata.h"
53 #define prnt PrintAndLog
54 #else
55 uint8_t g_debugMode=0;
56 #define prnt dummy
57 #endif
58
59 uint8_t justNoise(uint8_t *BitStream, size_t size) {
60 //test samples are not just noise
61 uint8_t justNoise1 = 1;
62 for(size_t idx=0; idx < size && justNoise1 ;idx++){
63 justNoise1 = BitStream[idx] < FSK_PSK_THRESHOLD;
64 }
65 return justNoise1;
66 }
67
68 //by marshmellow
69 //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
70 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) {
71 *high=0;
72 *low=255;
73 // get high and low thresholds
74 for (size_t i=0; i < size; i++){
75 if (BitStream[i] > *high) *high = BitStream[i];
76 if (BitStream[i] < *low) *low = BitStream[i];
77 }
78 if (*high < FSK_PSK_THRESHOLD) return -1; // just noise
79 *high = ((*high-128)*fuzzHi + 12800)/100;
80 *low = ((*low-128)*fuzzLo + 12800)/100;
81 return 1;
82 }
83
84 // by marshmellow
85 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
86 // returns 1 if passed
87 bool parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
88 return oddparity32(bits) ^ pType;
89 }
90
91 // by marshmellow
92 // takes a array of binary values, start position, length of bits per parity (includes parity bit - MAX 32),
93 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
94 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) {
95 uint32_t parityWd = 0;
96 size_t bitCnt = 0;
97 for (int word = 0; word < (bLen); word+=pLen) {
98 for (int bit=0; bit < pLen; bit++) {
99 if (word+bit >= bLen) break;
100 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
101 BitStream[bitCnt++] = (BitStream[startIdx+word+bit]);
102 }
103 if (word+pLen > bLen) break;
104
105 bitCnt--; // overwrite parity with next data
106 // if parity fails then return 0
107 switch (pType) {
108 case 3: if (BitStream[bitCnt]==1) {return 0;} break; //should be 0 spacer bit
109 case 2: if (BitStream[bitCnt]==0) {return 0;} break; //should be 1 spacer bit
110 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
111 }
112 parityWd = 0;
113 }
114 // if we got here then all the parities passed
115 //return size
116 return bitCnt;
117 }
118
119 // by marshmellow
120 // takes a array of binary values, length of bits per parity (includes parity bit),
121 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
122 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
123 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) {
124 uint32_t parityWd = 0;
125 size_t j = 0, bitCnt = 0;
126 for (int word = 0; word < sourceLen; word+=pLen-1) {
127 for (int bit=0; bit < pLen-1; bit++){
128 parityWd = (parityWd << 1) | BitSource[word+bit];
129 dest[j++] = (BitSource[word+bit]);
130 }
131 // if parity fails then return 0
132 switch (pType) {
133 case 3: dest[j++]=0; break; // marker bit which should be a 0
134 case 2: dest[j++]=1; break; // marker bit which should be a 1
135 default:
136 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
137 break;
138 }
139 bitCnt += pLen;
140 parityWd = 0;
141 }
142 // if we got here then all the parities passed
143 //return ID start index and size
144 return bitCnt;
145 }
146
147 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) {
148 uint32_t num = 0;
149 for(int i = 0 ; i < numbits ; i++)
150 {
151 num = (num << 1) | (*src);
152 src++;
153 }
154 return num;
155 }
156
157 //least significant bit first
158 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) {
159 uint32_t num = 0;
160 for(int i = 0 ; i < numbits ; i++)
161 {
162 num = (num << 1) | *(src + (numbits-(i+1)));
163 }
164 return num;
165 }
166
167 // 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
168 // fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
169 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
170 // Sanity check. If preamble length is bigger than bitstream length.
171 if ( *size <= pLen ) return false;
172
173 uint8_t foundCnt = 0;
174 for (size_t idx = 0; idx < *size - pLen; idx++) {
175 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
176 //first index found
177 foundCnt++;
178 if (foundCnt == 1) {
179 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
180 *startIdx = idx;
181 if (findone) return true;
182 } else if (foundCnt == 2) {
183 *size = idx - *startIdx;
184 return true;
185 }
186 }
187 }
188 return false;
189 }
190
191 //by marshmellow
192 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
193 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) {
194 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
195 }
196
197 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
198 size_t findModStart(uint8_t dest[], size_t size, uint8_t expWaveSize) {
199 size_t i = 0;
200 size_t waveSizeCnt = 0;
201 uint8_t thresholdCnt = 0;
202 bool isAboveThreshold = dest[i++] >= FSK_PSK_THRESHOLD;
203 for (; i < size-20; i++ ) {
204 if(dest[i] < FSK_PSK_THRESHOLD && isAboveThreshold) {
205 thresholdCnt++;
206 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
207 isAboveThreshold = false;
208 waveSizeCnt = 0;
209 } else if (dest[i] >= FSK_PSK_THRESHOLD && !isAboveThreshold) {
210 thresholdCnt++;
211 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
212 isAboveThreshold = true;
213 waveSizeCnt = 0;
214 } else {
215 waveSizeCnt++;
216 }
217 if (thresholdCnt > 10) break;
218 }
219 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
220 return i;
221 }
222
223 int getClosestClock(int testclk) {
224 uint8_t fndClk[] = {8,16,32,40,50,64,128};
225
226 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++)
227 if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1)
228 return fndClk[clkCnt];
229
230 return 0;
231 }
232
233 void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) {
234 while ((samples[*i] > low) && (*i < size))
235 *i+=1;
236 }
237
238 void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) {
239 while ((samples[*i] < high) && (*i < size))
240 *i+=1;
241 }
242
243 // load wave counters
244 bool loadWaveCounters(uint8_t samples[], size_t size, int lowToLowWaveLen[], int highToLowWaveLen[], int *waveCnt, int *skip, int *minClk, int *high, int *low) {
245 size_t i=0, firstLow, firstHigh;
246 size_t testsize = (size < 512) ? size : 512;
247
248 if ( getHiLo(samples, testsize, high, low, 80, 80) == -1 ) {
249 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
250 return false; //just noise
251 }
252
253 // get to first full low to prime loop and skip incomplete first pulse
254 getNextHigh(samples, size, *high, &i);
255 getNextLow(samples, size, *low, &i);
256 *skip = i;
257
258 // populate tmpbuff buffer with pulse lengths
259 while (i < size) {
260 // measure from low to low
261 firstLow = i;
262 //find first high point for this wave
263 getNextHigh(samples, size, *high, &i);
264 firstHigh = i;
265
266 getNextLow(samples, size, *low, &i);
267
268 if (*waveCnt >= (size/LOWEST_DEFAULT_CLOCK))
269 break;
270
271 highToLowWaveLen[*waveCnt] = i - firstHigh; //first high to first low
272 lowToLowWaveLen[*waveCnt] = i - firstLow;
273 *waveCnt += 1;
274 if (i-firstLow < *minClk && i < size) {
275 *minClk = i - firstLow;
276 }
277 }
278 return true;
279 }
280
281 size_t pskFindFirstPhaseShift(uint8_t samples[], size_t size, uint8_t *curPhase, size_t waveStart, uint16_t fc, uint16_t *fullWaveLen) {
282 uint16_t loopCnt = (size+3 < 4096) ? size : 4096; //don't need to loop through entire array...
283
284 uint16_t avgWaveVal=0, lastAvgWaveVal=0;
285 size_t i = waveStart, waveEnd, waveLenCnt, firstFullWave;
286 for (; i<loopCnt; i++) {
287 // find peak // was "samples[i] + fc" but why? must have been used to weed out some wave error... removed..
288 if (samples[i] < samples[i+1] && samples[i+1] >= samples[i+2]){
289 waveEnd = i+1;
290 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u", waveEnd, waveStart);
291 waveLenCnt = waveEnd-waveStart;
292 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+8)){ //not first peak and is a large wave but not out of whack
293 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
294 firstFullWave = waveStart;
295 *fullWaveLen = waveLenCnt;
296 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
297 if (lastAvgWaveVal > FSK_PSK_THRESHOLD) *curPhase ^= 1;
298 return firstFullWave;
299 }
300 waveStart = i+1;
301 avgWaveVal = 0;
302 }
303 avgWaveVal += samples[i+2];
304 }
305 return 0;
306 }
307
308 //by marshmellow
309 //amplify based on ask edge detection - not accurate enough to use all the time
310 void askAmp(uint8_t *BitStream, size_t size) {
311 uint8_t Last = 128;
312 for(size_t i = 1; i<size; i++){
313 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
314 Last = 255;
315 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
316 Last = 0;
317
318 BitStream[i-1] = Last;
319 }
320 return;
321 }
322
323 uint32_t manchesterEncode2Bytes(uint16_t datain) {
324 uint32_t output = 0;
325 uint8_t curBit = 0;
326 for (uint8_t i=0; i<16; i++) {
327 curBit = (datain >> (15-i) & 1);
328 output |= (1<<(((15-i)*2)+curBit));
329 }
330 return output;
331 }
332
333 //by marshmellow
334 //encode binary data into binary manchester
335 //NOTE: BitStream must have triple the size of "size" available in memory to do the swap
336 int ManchesterEncode(uint8_t *BitStream, size_t size) {
337 //allow up to 4K out (means BitStream must be at least 2048+4096 to handle the swap)
338 size = (size>2048) ? 2048 : size;
339 size_t modIdx = size;
340 size_t i;
341 for (size_t idx=0; idx < size; idx++){
342 BitStream[idx+modIdx++] = BitStream[idx];
343 BitStream[idx+modIdx++] = BitStream[idx]^1;
344 }
345 for (i=0; i<(size*2); i++){
346 BitStream[i] = BitStream[i+size];
347 }
348 return i;
349 }
350
351 // by marshmellow
352 // to detect a wave that has heavily clipped (clean) samples
353 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) {
354 bool allArePeaks = true;
355 uint16_t cntPeaks=0;
356 size_t loopEnd = 512+160;
357 if (loopEnd > size) loopEnd = size;
358 for (size_t i=160; i<loopEnd; i++){
359 if (dest[i]>low && dest[i]<high)
360 allArePeaks = false;
361 else
362 cntPeaks++;
363 }
364 if (!allArePeaks){
365 if (cntPeaks > 300) return true;
366 }
367 return allArePeaks;
368 }
369
370 //**********************************************************************************************
371 //-------------------Clock / Bitrate Detection Section------------------------------------------
372 //**********************************************************************************************
373
374 // by marshmellow
375 // to help detect clocks on heavily clipped samples
376 // based on count of low to low
377 int DetectStrongAskClock(uint8_t dest[], size_t size, int high, int low, int *clock) {
378 size_t startwave;
379 size_t i = 100;
380 size_t minClk = 255;
381 int shortestWaveIdx = 0;
382 // get to first full low to prime loop and skip incomplete first pulse
383 getNextHigh(dest, size, high, &i);
384 getNextLow(dest, size, low, &i);
385
386 // loop through all samples
387 while (i < size) {
388 // measure from low to low
389 startwave = i;
390
391 getNextHigh(dest, size, high, &i);
392 getNextLow(dest, size, low, &i);
393 //get minimum measured distance
394 if (i-startwave < minClk && i < size) {
395 minClk = i - startwave;
396 shortestWaveIdx = startwave;
397 }
398 }
399 // set clock
400 if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk);
401 *clock = getClosestClock(minClk);
402 if (*clock == 0)
403 return 0;
404
405 return shortestWaveIdx;
406 }
407
408 // by marshmellow
409 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
410 // maybe somehow adjust peak trimming value based on samples to fix?
411 // return start index of best starting position for that clock and return clock (by reference)
412 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) {
413 size_t i=1;
414 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
415 uint8_t clkEnd = 9;
416 uint8_t loopCnt = 255; //don't need to loop through entire array...
417 if (size <= loopCnt+60) return -1; //not enough samples
418 size -= 60; //sometimes there is a strange end wave - filter out this....
419 //if we already have a valid clock
420 uint8_t clockFnd=0;
421 for (;i<clkEnd;++i)
422 if (clk[i] == *clock) clockFnd = i;
423 //clock found but continue to find best startpos
424
425 //get high and low peak
426 int peak, low;
427 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
428
429 //test for large clean peaks
430 if (!clockFnd){
431 if (DetectCleanAskWave(dest, size, peak, low)==1){
432 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
433 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
434 if (ans > 0) {
435 return ans; //return shortest wave start position
436 }
437 }
438 }
439 uint8_t ii;
440 uint8_t clkCnt, tol = 0;
441 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
442 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
443 size_t errCnt = 0;
444 size_t arrLoc, loopEnd;
445
446 if (clockFnd>0) {
447 clkCnt = clockFnd;
448 clkEnd = clockFnd+1;
449 }
450 else clkCnt=1;
451
452 //test each valid clock from smallest to greatest to see which lines up
453 for(; clkCnt < clkEnd; clkCnt++){
454 if (clk[clkCnt] <= 32){
455 tol=1;
456 }else{
457 tol=0;
458 }
459 //if no errors allowed - keep start within the first clock
460 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
461 bestErr[clkCnt]=1000;
462 //try lining up the peaks by moving starting point (try first few clocks)
463 for (ii=0; ii < loopCnt; ii++){
464 if (dest[ii] < peak && dest[ii] > low) continue;
465
466 errCnt=0;
467 // now that we have the first one lined up test rest of wave array
468 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
469 for (i=0; i < loopEnd; ++i){
470 arrLoc = ii + (i * clk[clkCnt]);
471 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
472 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
473 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
474 }else{ //error no peak detected
475 errCnt++;
476 }
477 }
478 //if we found no errors then we can stop here and a low clock (common clocks)
479 // this is correct one - return this clock
480 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
481 if(errCnt==0 && clkCnt<7) {
482 if (!clockFnd) *clock = clk[clkCnt];
483 return ii;
484 }
485 //if we found errors see if it is lowest so far and save it as best run
486 if(errCnt<bestErr[clkCnt]){
487 bestErr[clkCnt]=errCnt;
488 bestStart[clkCnt]=ii;
489 }
490 }
491 }
492 uint8_t iii;
493 uint8_t best=0;
494 for (iii=1; iii<clkEnd; ++iii){
495 if (bestErr[iii] < bestErr[best]){
496 if (bestErr[iii] == 0) bestErr[iii]=1;
497 // current best bit to error ratio vs new bit to error ratio
498 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
499 best = iii;
500 }
501 }
502 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]);
503 }
504 if (!clockFnd) *clock = clk[best];
505 return bestStart[best];
506 }
507
508 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
509 //find shortest transition from high to low
510 size_t i = 0;
511 size_t transition1 = 0;
512 int lowestTransition = 255;
513 bool lastWasHigh = false;
514
515 //find first valid beginning of a high or low wave
516 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
517 ++i;
518 while ((dest[i] < peak && dest[i] > low) && (i < size))
519 ++i;
520 lastWasHigh = (dest[i] >= peak);
521
522 if (i==size) return 0;
523 transition1 = i;
524
525 for (;i < size; i++) {
526 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
527 lastWasHigh = (dest[i] >= peak);
528 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
529 transition1 = i;
530 }
531 }
532 if (lowestTransition == 255) lowestTransition = 0;
533 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
534 return lowestTransition;
535 }
536
537 //by marshmellow
538 //detect nrz clock by reading #peaks vs no peaks(or errors)
539 int DetectNRZClock(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
540 size_t i=0;
541 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
542 size_t loopCnt = 4096; //don't need to loop through entire array...
543 if (size == 0) return 0;
544 if (size<loopCnt) loopCnt = size-20;
545 //if we already have a valid clock quit
546 for (; i < 8; ++i)
547 if (clk[i] == clock) return clock;
548
549 //get high and low peak
550 int peak, low;
551 if (getHiLo(dest, loopCnt, &peak, &low, 90, 90) < 1) return 0;
552
553 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
554 size_t ii;
555 uint8_t clkCnt;
556 uint8_t tol = 0;
557 uint16_t smplCnt = 0;
558 int16_t peakcnt = 0;
559 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
560 uint16_t minPeak = 255;
561 bool firstpeak = true;
562 //test for large clipped waves - ignore first peak
563 for (i=0; i<loopCnt; i++) {
564 if (dest[i] >= peak || dest[i] <= low) {
565 if (firstpeak) continue;
566 smplCnt++;
567 } else {
568 firstpeak = false;
569 if (smplCnt > 0) {
570 if (minPeak > smplCnt && smplCnt > 7) minPeak = smplCnt;
571 peakcnt++;
572 if (g_debugMode == 2) prnt("DEBUG NRZ: minPeak: %d, smplCnt: %d, peakcnt: %d",minPeak,smplCnt,peakcnt);
573 smplCnt = 0;
574 }
575 }
576 }
577 if (minPeak < 8) return 0;
578 bool errBitHigh = 0;
579 bool bitHigh = 0;
580 uint8_t ignoreCnt = 0;
581 uint8_t ignoreWindow = 4;
582 bool lastPeakHigh = 0;
583 int lastBit = 0;
584 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
585 peakcnt=0;
586 //test each valid clock from smallest to greatest to see which lines up
587 for(clkCnt=0; clkCnt < 8; ++clkCnt) {
588 //ignore clocks smaller than smallest peak
589 if (clk[clkCnt] < minPeak - (clk[clkCnt]/4)) continue;
590 //try lining up the peaks by moving starting point (try first 256)
591 for (ii=20; ii < loopCnt; ++ii) {
592 if ((dest[ii] >= peak) || (dest[ii] <= low)) {
593 peakcnt = 0;
594 bitHigh = false;
595 ignoreCnt = 0;
596 lastBit = ii-clk[clkCnt];
597 //loop through to see if this start location works
598 for (i = ii; i < size-20; ++i) {
599 //if we are at a clock bit
600 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
601 //test high/low
602 if (dest[i] >= peak || dest[i] <= low) {
603 //if same peak don't count it
604 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
605 peakcnt++;
606 }
607 lastPeakHigh = (dest[i] >= peak);
608 bitHigh = true;
609 errBitHigh = false;
610 ignoreCnt = ignoreWindow;
611 lastBit += clk[clkCnt];
612 } else if (i == lastBit + clk[clkCnt] + tol) {
613 lastBit += clk[clkCnt];
614 }
615 //else if not a clock bit and no peaks
616 } else if (dest[i] < peak && dest[i] > low) {
617 if (ignoreCnt==0) {
618 bitHigh=false;
619 if (errBitHigh==true) peakcnt--;
620 errBitHigh=false;
621 } else {
622 ignoreCnt--;
623 }
624 // else if not a clock bit but we have a peak
625 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
626 //error bar found no clock...
627 errBitHigh=true;
628 }
629 }
630 if(peakcnt>peaksdet[clkCnt]) {
631 bestStart[clkCnt]=ii;
632 peaksdet[clkCnt]=peakcnt;
633 }
634 }
635 }
636 }
637 int iii=7;
638 uint8_t best=0;
639 for (iii=7; iii > 0; iii--) {
640 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
641 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
642 best = iii;
643 }
644 } else if (peaksdet[iii] > peaksdet[best]) {
645 best = iii;
646 }
647 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);
648 }
649 *clockStartIdx = bestStart[best];
650 return clk[best];
651 }
652
653 //by marshmellow
654 //countFC is to detect the field clock lengths.
655 //counts and returns the 2 most common wave lengths
656 //mainly used for FSK field clock detection
657 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) {
658 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
659 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
660 uint8_t fcLensFnd = 0;
661 uint8_t lastFCcnt = 0;
662 uint8_t fcCounter = 0;
663 size_t i;
664 if (size < 180) return 0;
665
666 // prime i to first up transition
667 for (i = 160; i < size-20; i++)
668 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
669 break;
670
671 for (; i < size-20; i++){
672 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
673 // new up transition
674 fcCounter++;
675 if (fskAdj){
676 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
677 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
678 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
679 if ((fcCounter==9) || fcCounter==4) fcCounter++;
680 // save last field clock count (fc/xx)
681 lastFCcnt = fcCounter;
682 }
683 // find which fcLens to save it to:
684 for (int ii=0; ii<15; ii++){
685 if (fcLens[ii]==fcCounter){
686 fcCnts[ii]++;
687 fcCounter=0;
688 break;
689 }
690 }
691 if (fcCounter>0 && fcLensFnd<15){
692 //add new fc length
693 fcCnts[fcLensFnd]++;
694 fcLens[fcLensFnd++]=fcCounter;
695 }
696 fcCounter=0;
697 } else {
698 // count sample
699 fcCounter++;
700 }
701 }
702
703 uint8_t best1=14, best2=14, best3=14;
704 uint16_t maxCnt1=0;
705 // go through fclens and find which ones are bigest 2
706 for (i=0; i<15; i++){
707 // get the 3 best FC values
708 if (fcCnts[i]>maxCnt1) {
709 best3=best2;
710 best2=best1;
711 maxCnt1=fcCnts[i];
712 best1=i;
713 } else if(fcCnts[i]>fcCnts[best2]){
714 best3=best2;
715 best2=i;
716 } else if(fcCnts[i]>fcCnts[best3]){
717 best3=i;
718 }
719 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]);
720 if (fcLens[i]==0) break;
721 }
722 if (fcLens[best1]==0) return 0;
723 uint8_t fcH=0, fcL=0;
724 if (fcLens[best1]>fcLens[best2]){
725 fcH=fcLens[best1];
726 fcL=fcLens[best2];
727 } else{
728 fcH=fcLens[best2];
729 fcL=fcLens[best1];
730 }
731 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
732 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]);
733 return 0; //lots of waves not psk or fsk
734 }
735 // TODO: take top 3 answers and compare to known Field clocks to get top 2
736
737 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
738 if (fskAdj) return fcs;
739 return (uint16_t)fcLens[best2] << 8 | fcLens[best1];
740 }
741
742 //by marshmellow
743 //detect psk clock by reading each phase shift
744 // a phase shift is determined by measuring the sample length of each wave
745 int DetectPSKClock(uint8_t dest[], size_t size, int clock, size_t *firstPhaseShift, uint8_t *curPhase, uint8_t *fc) {
746 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
747 uint16_t loopCnt = 4096; //don't need to loop through entire array...
748 if (size == 0) return 0;
749 if (size+3<loopCnt) loopCnt = size-20;
750
751 uint16_t fcs = countFC(dest, size, 0);
752 *fc = fcs & 0xFF;
753 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d, FC2: %d",*fc, fcs>>8);
754 if ((fcs>>8) == 10 && *fc == 8) return 0;
755 if (*fc!=2 && *fc!=4 && *fc!=8) return 0;
756
757 //if we already have a valid clock quit
758 size_t i=1;
759 for (; i < 8; ++i)
760 if (clk[i] == clock) return clock;
761
762 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
763
764 uint8_t clkCnt, tol=1;
765 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0, fullWaveLen=0;
766 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
767 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
768
769 //find start of modulating data in trace
770 i = findModStart(dest, size, *fc);
771
772 firstFullWave = pskFindFirstPhaseShift(dest, size, curPhase, i, *fc, &fullWaveLen);
773 if (firstFullWave == 0) {
774 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
775 // so skip a little to ensure we are past any Start Signal
776 firstFullWave = 160;
777 fullWaveLen = 0;
778 }
779
780 *firstPhaseShift = firstFullWave;
781 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
782 //test each valid clock from greatest to smallest to see which lines up
783 for(clkCnt=7; clkCnt >= 1 ; clkCnt--) {
784 tol = *fc/2;
785 lastClkBit = firstFullWave; //set end of wave as clock align
786 waveStart = 0;
787 errCnt=0;
788 peakcnt=0;
789 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
790
791 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
792 //top edge of wave = start of new wave
793 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
794 if (waveStart == 0) {
795 waveStart = i+1;
796 waveLenCnt=0;
797 } else { //waveEnd
798 waveEnd = i+1;
799 waveLenCnt = waveEnd-waveStart;
800 if (waveLenCnt > *fc){
801 //if this wave is a phase shift
802 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);
803 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
804 peakcnt++;
805 lastClkBit+=clk[clkCnt];
806 } else if (i<lastClkBit+8){
807 //noise after a phase shift - ignore
808 } else { //phase shift before supposed to based on clock
809 errCnt++;
810 }
811 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + *fc){
812 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
813 }
814 waveStart=i+1;
815 }
816 }
817 }
818 if (errCnt == 0){
819 return clk[clkCnt];
820 }
821 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
822 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
823 }
824 //all tested with errors
825 //return the highest clk with the most peaks found
826 uint8_t best=7;
827 for (i=7; i>=1; i--){
828 if (peaksdet[i] > peaksdet[best]) {
829 best = i;
830 }
831 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
832 }
833 return clk[best];
834 }
835
836 //by marshmellow
837 //detects the bit clock for FSK given the high and low Field Clocks
838 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
839 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
840 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
841 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
842 uint8_t rfLensFnd = 0;
843 uint8_t lastFCcnt = 0;
844 uint16_t fcCounter = 0;
845 uint16_t rfCounter = 0;
846 uint8_t firstBitFnd = 0;
847 size_t i;
848 if (size == 0) return 0;
849
850 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
851 rfLensFnd=0;
852 fcCounter=0;
853 rfCounter=0;
854 firstBitFnd=0;
855 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
856 // prime i to first peak / up transition
857 for (i = 160; i < size-20; i++)
858 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
859 break;
860
861 for (; i < size-20; i++){
862 fcCounter++;
863 rfCounter++;
864
865 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
866 continue;
867 // else new peak
868 // if we got less than the small fc + tolerance then set it to the small fc
869 // if it is inbetween set it to the last counter
870 if (fcCounter < fcHigh && fcCounter > fcLow)
871 fcCounter = lastFCcnt;
872 else if (fcCounter < fcLow+fcTol)
873 fcCounter = fcLow;
874 else //set it to the large fc
875 fcCounter = fcHigh;
876
877 //look for bit clock (rf/xx)
878 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
879 //not the same size as the last wave - start of new bit sequence
880 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
881 for (int ii=0; ii<15; ii++){
882 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
883 rfCnts[ii]++;
884 rfCounter = 0;
885 break;
886 }
887 }
888 if (rfCounter > 0 && rfLensFnd < 15){
889 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
890 rfCnts[rfLensFnd]++;
891 rfLens[rfLensFnd++] = rfCounter;
892 }
893 } else {
894 *firstClockEdge = i;
895 firstBitFnd++;
896 }
897 rfCounter=0;
898 lastFCcnt=fcCounter;
899 }
900 fcCounter=0;
901 }
902 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
903
904 for (i=0; i<15; i++){
905 //get highest 2 RF values (might need to get more values to compare or compare all?)
906 if (rfCnts[i]>rfCnts[rfHighest]){
907 rfHighest3=rfHighest2;
908 rfHighest2=rfHighest;
909 rfHighest=i;
910 } else if(rfCnts[i]>rfCnts[rfHighest2]){
911 rfHighest3=rfHighest2;
912 rfHighest2=i;
913 } else if(rfCnts[i]>rfCnts[rfHighest3]){
914 rfHighest3=i;
915 }
916 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
917 }
918 // set allowed clock remainder tolerance to be 1 large field clock length+1
919 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
920 uint8_t tol1 = fcHigh+1;
921
922 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
923
924 // loop to find the highest clock that has a remainder less than the tolerance
925 // compare samples counted divided by
926 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
927 int ii=7;
928 for (; ii>=2; ii--){
929 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
930 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
931 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
932 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
933 break;
934 }
935 }
936 }
937 }
938
939 if (ii<2) return 0; // oops we went too far
940
941 return clk[ii];
942 }
943
944 //**********************************************************************************************
945 //--------------------Modulation Demods &/or Decoding Section-----------------------------------
946 //**********************************************************************************************
947
948 // 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...
949 bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, size_t *i) {
950 if (buffSize < *i+4) return false;
951
952 for (; *i < buffSize - 4; *i+=1) {
953 *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...
954 if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
955 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
956 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
957 if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
958 *stStopLoc = *i + 3;
959 return true;
960 }
961 }
962 }
963 }
964 }
965 return false;
966 }
967 //by marshmellow
968 //attempt to identify a Sequence Terminator in ASK modulated raw wave
969 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
970 size_t bufsize = *size;
971 //need to loop through all samples and identify our clock, look for the ST pattern
972 int clk = 0;
973 int tol = 0;
974 int j=0, high, low, skip=0, start=0, end=0, minClk=255;
975 size_t i = 0;
976 //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
977 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
978 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...
979 //size_t testsize = (bufsize < 512) ? bufsize : 512;
980 int phaseoff = 0;
981 high = low = 128;
982 memset(tmpbuff, 0, sizeof(tmpbuff));
983 memset(waveLen, 0, sizeof(waveLen));
984
985 if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
986 // set clock - might be able to get this externally and remove this work...
987 clk = getClosestClock(minClk);
988 // clock not found - ERROR
989 if (clk == 0) {
990 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
991 return false;
992 }
993 *foundclock = clk;
994
995 tol = clk/8;
996 if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
997 // first ST not found - ERROR
998 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
999 return false;
1000 } else {
1001 if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
1002 }
1003 if (waveLen[i+2] > clk*1+tol)
1004 phaseoff = 0;
1005 else
1006 phaseoff = clk/2;
1007
1008 // skip over the remainder of ST
1009 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1010
1011 // now do it again to find the end
1012 int dummy1 = 0;
1013 end = skip;
1014 i+=3;
1015 if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
1016 //didn't find second ST - ERROR
1017 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1018 return false;
1019 }
1020 end -= phaseoff;
1021 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);
1022 //now begin to trim out ST so we can use normal demod cmds
1023 start = skip;
1024 size_t datalen = end - start;
1025 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1026 if ( clk - (datalen % clk) <= clk/8) {
1027 // padd the amount off - could be problematic... but shouldn't happen often
1028 datalen += clk - (datalen % clk);
1029 } else if ( (datalen % clk) <= clk/8 ) {
1030 // padd the amount off - could be problematic... but shouldn't happen often
1031 datalen -= datalen % clk;
1032 } else {
1033 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1034 return false;
1035 }
1036 // if datalen is less than one t55xx block - ERROR
1037 if (datalen/clk < 8*4) {
1038 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1039 return false;
1040 }
1041 size_t dataloc = start;
1042 if (buffer[dataloc-(clk*4)-(clk/4)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1043 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1044 for ( i=0; i <= (clk/4); ++i ) {
1045 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1046 dataloc -= i;
1047 break;
1048 }
1049 }
1050 }
1051
1052 size_t newloc = 0;
1053 i=0;
1054 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1055 bool firstrun = true;
1056 // warning - overwriting buffer given with raw wave data with ST removed...
1057 while ( dataloc < bufsize-(clk/2) ) {
1058 //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)
1059 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+clk/4]<high && buffer[dataloc+clk/4]>low) {
1060 for(i=0; i < clk/2-tol; ++i) {
1061 buffer[dataloc+i] = high+5;
1062 }
1063 } //test for small spike outlier (high between two lows) in the case of very strong waves
1064 if (buffer[dataloc] > low && buffer[dataloc+clk/4] <= low) {
1065 for(i=0; i < clk/4; ++i) {
1066 buffer[dataloc+i] = buffer[dataloc+clk/4];
1067 }
1068 }
1069 if (firstrun) {
1070 *stend = dataloc;
1071 *ststart = dataloc-(clk*4);
1072 firstrun=false;
1073 }
1074 for (i=0; i<datalen; ++i) {
1075 if (i+newloc < bufsize) {
1076 if (i+newloc < dataloc)
1077 buffer[i+newloc] = buffer[dataloc];
1078
1079 dataloc++;
1080 }
1081 }
1082 newloc += i;
1083 //skip next ST - we just assume it will be there from now on...
1084 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1085 dataloc += clk*4;
1086 }
1087 *size = newloc;
1088 return true;
1089 }
1090
1091 //by marshmellow
1092 //take 11 10 01 11 00 and make 01100 ... miller decoding
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!
1096 int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
1097 if (*size < 16) return -1;
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;
1102 //find alignment, needs 4 1s or 0s to properly align
1103 for (i=1; i < *size-1; i++) {
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 }
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;
1122
1123 if (bitCnt > MaxBits) break;
1124 }
1125 *size = bitCnt;
1126 return errCnt;
1127 }
1128
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
1133 int 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++;
1160 }
1161 if(bitnum>MaxBits) break;
1162 }
1163 *size=bitnum;
1164 return errCnt;
1165 }
1166
1167 //by marshmellow
1168 //take 10 and 01 and manchester decode
1169 //run through 2 times and take least errCnt
1170 int 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;
1194 } else {
1195 BitStream[bitnum++]=7;
1196 }
1197 if(bitnum>MaxBits) break;
1198 }
1199 *size=bitnum;
1200 return bestErr;
1201 }
1202
1203 //by marshmellow
1204 //demodulates strong heavily clipped samples
1205 int 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;
1228 }
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
1244 }
1245 } else { //haven't hit new high or new low yet
1246 smplCnt++;
1247 }
1248 }
1249 }
1250 *size = bitCnt;
1251 return errCnt;
1252 }
1253
1254 //by marshmellow
1255 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
1256 int 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);
1263
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
1274
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;
1315 }
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;
1328 }
1329 midBit = 1;
1330 }
1331 if (bitnum >= MaxBits) break;
1332 }
1333 *size = bitnum;
1334 return errCnt;
1335 }
1336
1337 int 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
1344 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1345 if (justNoise(dest, *size)) return -1;
1346 size_t clkStartIdx = 0;
1347 *clk = DetectNRZClock(dest, *size, *clk, &clkStartIdx);
1348 if (*clk==0) return -2;
1349 size_t i, gLen = 4096;
1350 if (gLen>*size) gLen = *size-20;
1351 int high, low;
1352 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1353
1354 uint8_t bit=0;
1355 //convert wave samples to 1's and 0's
1356 for(i=20; i < *size-20; i++){
1357 if (dest[i] >= high) bit = 1;
1358 if (dest[i] <= low) bit = 0;
1359 dest[i] = bit;
1360 }
1361 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1362 size_t lastBit = 0;
1363 size_t numBits = 0;
1364 for(i=21; i < *size-20; i++) {
1365 //if transition detected or large number of same bits - store the passed bits
1366 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1367 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1368 numBits += (i - lastBit + (*clk/4)) / *clk;
1369 if (lastBit == 0) {
1370 *startIdx = i - (numBits * *clk);
1371 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1372 }
1373 lastBit = i-1;
1374 }
1375 }
1376 *size = numBits;
1377 return 0;
1378 }
1379
1380 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
1381 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1382 size_t last_transition = 0;
1383 size_t idx = 1;
1384 if (fchigh==0) fchigh=10;
1385 if (fclow==0) fclow=8;
1386 //set the threshold close to 0 (graph) or 128 std to avoid static
1387 size_t preLastSample = 0;
1388 size_t LastSample = 0;
1389 size_t currSample = 0;
1390 if ( size < 1024 ) return 0; // not enough samples
1391
1392 //find start of modulating data in trace
1393 idx = findModStart(dest, size, fchigh);
1394 // Need to threshold first sample
1395 if(dest[idx] < FSK_PSK_THRESHOLD) dest[0] = 0;
1396 else dest[0] = 1;
1397
1398 last_transition = idx;
1399 idx++;
1400 size_t numBits = 0;
1401 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
1402 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
1403 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
1404 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
1405 for(; idx < size; idx++) {
1406 // threshold current value
1407 if (dest[idx] < FSK_PSK_THRESHOLD) dest[idx] = 0;
1408 else dest[idx] = 1;
1409
1410 // Check for 0->1 transition
1411 if (dest[idx-1] < dest[idx]) {
1412 preLastSample = LastSample;
1413 LastSample = currSample;
1414 currSample = idx-last_transition;
1415 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
1416 //do nothing with extra garbage
1417 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
1418 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
1419 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
1420 dest[numBits-1]=1;
1421 }
1422 dest[numBits++]=1;
1423 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1424 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
1425 //do nothing with beginning garbage and reset.. should be rare..
1426 numBits = 0;
1427 } 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)
1428 dest[numBits++]=1;
1429 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1430 } else { //9+ = 10 sample waves (or 6+ = 7)
1431 dest[numBits++]=0;
1432 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
1433 }
1434 last_transition = idx;
1435 }
1436 }
1437 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
1438 }
1439
1440 //translate 11111100000 to 10
1441 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
1442 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1443 uint8_t lastval=dest[0];
1444 size_t idx=0;
1445 size_t numBits=0;
1446 uint32_t n=1;
1447 for( idx=1; idx < size; idx++) {
1448 n++;
1449 if (dest[idx]==lastval) continue; //skip until we hit a transition
1450
1451 //find out how many bits (n) we collected (use 1/2 clk tolerance)
1452 //if lastval was 1, we have a 1->0 crossing
1453 if (dest[idx-1]==1) {
1454 n = (n * fclow + rfLen/2) / rfLen;
1455 } else {// 0->1 crossing
1456 n = (n * fchigh + rfLen/2) / rfLen;
1457 }
1458 if (n == 0) n = 1;
1459
1460 //first transition - save startidx
1461 if (numBits == 0) {
1462 if (lastval == 1) { //high to low
1463 *startIdx += (fclow * idx) - (n*rfLen);
1464 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
1465 } else {
1466 *startIdx += (fchigh * idx) - (n*rfLen);
1467 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
1468 }
1469 }
1470
1471 //add to our destination the bits we collected
1472 memset(dest+numBits, dest[idx-1]^invert , n);
1473 numBits += n;
1474 n=0;
1475 lastval=dest[idx];
1476 }//end for
1477 // if valid extra bits at the end were all the same frequency - add them in
1478 if (n > rfLen/fchigh) {
1479 if (dest[idx-2]==1) {
1480 n = (n * fclow + rfLen/2) / rfLen;
1481 } else {
1482 n = (n * fchigh + rfLen/2) / rfLen;
1483 }
1484 memset(dest+numBits, dest[idx-1]^invert , n);
1485 numBits += n;
1486 }
1487 return numBits;
1488 }
1489
1490 //by marshmellow (from holiman's base)
1491 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
1492 int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1493 // FSK demodulator
1494 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
1495 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
1496 return size;
1497 }
1498
1499 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
1500 int startIdx=0;
1501 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
1502 }
1503
1504 // by marshmellow
1505 // convert psk1 demod to psk2 demod
1506 // only transition waves are 1s
1507 void psk1TOpsk2(uint8_t *BitStream, size_t size) {
1508 size_t i=1;
1509 uint8_t lastBit=BitStream[0];
1510 for (; i<size; i++){
1511 if (BitStream[i]==7){
1512 //ignore errors
1513 } else if (lastBit!=BitStream[i]){
1514 lastBit=BitStream[i];
1515 BitStream[i]=1;
1516 } else {
1517 BitStream[i]=0;
1518 }
1519 }
1520 return;
1521 }
1522
1523 // by marshmellow
1524 // convert psk2 demod to psk1 demod
1525 // from only transition waves are 1s to phase shifts change bit
1526 void psk2TOpsk1(uint8_t *BitStream, size_t size) {
1527 uint8_t phase=0;
1528 for (size_t i=0; i<size; i++){
1529 if (BitStream[i]==1){
1530 phase ^=1;
1531 }
1532 BitStream[i]=phase;
1533 }
1534 return;
1535 }
1536
1537 //by marshmellow - demodulate PSK1 wave
1538 //uses wave lengths (# Samples)
1539 int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1540 if (*size < 170) return -1;
1541
1542 uint8_t curPhase = *invert;
1543 uint8_t fc=0;
1544 size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1545 uint16_t fullWaveLen=0, waveLenCnt=0, avgWaveVal;
1546 uint16_t errCnt=0, errCnt2=0;
1547
1548 *clock = DetectPSKClock(dest, *size, *clock, &firstFullWave, &curPhase, &fc);
1549 if (*clock <= 0) return -1;
1550 //if clock detect found firstfullwave...
1551 uint16_t tol = fc/2;
1552 if (firstFullWave == 0) {
1553 //find start of modulating data in trace
1554 i = findModStart(dest, *size, fc);
1555 //find first phase shift
1556 firstFullWave = pskFindFirstPhaseShift(dest, *size, &curPhase, i, fc, &fullWaveLen);
1557 if (firstFullWave == 0) {
1558 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1559 // so skip a little to ensure we are past any Start Signal
1560 firstFullWave = 160;
1561 memset(dest, curPhase, firstFullWave / *clock);
1562 } else {
1563 memset(dest, curPhase^1, firstFullWave / *clock);
1564 }
1565 } else {
1566 memset(dest, curPhase^1, firstFullWave / *clock);
1567 }
1568 //advance bits
1569 numBits += (firstFullWave / *clock);
1570 *startIdx = firstFullWave - (*clock * numBits)+2;
1571 //set start of wave as clock align
1572 lastClkBit = firstFullWave;
1573 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1574 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1575 waveStart = 0;
1576 dest[numBits++] = curPhase; //set first read bit
1577 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++) {
1578 //top edge of wave = start of new wave
1579 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]) {
1580 if (waveStart == 0) {
1581 waveStart = i+1;
1582 waveLenCnt = 0;
1583 avgWaveVal = dest[i+1];
1584 } else { //waveEnd
1585 waveEnd = i+1;
1586 waveLenCnt = waveEnd-waveStart;
1587 if (waveLenCnt > fc) {
1588 //this wave is a phase shift
1589 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1590 if (i+1 >= lastClkBit + *clock - tol) { //should be a clock bit
1591 curPhase ^= 1;
1592 dest[numBits++] = curPhase;
1593 lastClkBit += *clock;
1594 } else if (i < lastClkBit+10+fc) {
1595 //noise after a phase shift - ignore
1596 } else { //phase shift before supposed to based on clock
1597 errCnt++;
1598 dest[numBits++] = 7;
1599 }
1600 } else if (i+1 > lastClkBit + *clock + tol + fc) {
1601 lastClkBit += *clock; //no phase shift but clock bit
1602 dest[numBits++] = curPhase;
1603 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1604 errCnt2++;
1605 if(errCnt2 > 101) return errCnt2;
1606 avgWaveVal += dest[i+1];
1607 continue;
1608 }
1609 avgWaveVal = 0;
1610 waveStart = i+1;
1611 }
1612 }
1613 avgWaveVal += dest[i+1];
1614 }
1615 *size = numBits;
1616 return errCnt;
1617 }
1618
1619 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1620 int startIdx = 0;
1621 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
1622 }
1623
1624 //**********************************************************************************************
1625 //-----------------Tag format detection section-------------------------------------------------
1626 //**********************************************************************************************
1627
1628 // by marshmellow
1629 // FSK Demod then try to locate an AWID ID
1630 int AWIDdemodFSK(uint8_t *dest, size_t *size) {
1631 //make sure buffer has enough data
1632 if (*size < 96*50) return -1;
1633
1634 if (justNoise(dest, *size)) return -2;
1635
1636 // FSK demodulator
1637 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1638 if (*size < 96) return -3; //did we get a good demod?
1639
1640 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
1641 size_t startIdx = 0;
1642 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1643 if (errChk == 0) return -4; //preamble not found
1644 if (*size != 96) return -5;
1645 return (int)startIdx;
1646 }
1647
1648 //by marshmellow
1649 //takes 1s and 0s and searches for EM410x format - output EM ID
1650 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
1651 {
1652 //sanity checks
1653 if (*size < 64) return 0;
1654 if (BitStream[1]>1) return 0; //allow only 1s and 0s
1655
1656 // 111111111 bit pattern represent start of frame
1657 // include 0 in front to help get start pos
1658 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
1659 uint8_t errChk = 0;
1660 uint8_t FmtLen = 10; // sets of 4 bits = end data
1661 *startIdx = 0;
1662 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
1663 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
1664 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
1665
1666 //skip last 4bit parity row for simplicity
1667 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
1668 if (*size == 40) { // std em410x format
1669 *hi = 0;
1670 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
1671 } else if (*size == 88) { // long em format
1672 *hi = (bytebits_to_byte(BitStream, 24));
1673 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
1674 } else {
1675 if (g_debugMode) prnt("Error removing parity: %u", *size);
1676 return 0;
1677 }
1678 return 1;
1679 }
1680
1681 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
1682 // BitStream must contain previously askrawdemod and biphasedemoded data
1683 int FDXBdemodBI(uint8_t *dest, size_t *size) {
1684 //make sure buffer has enough data
1685 if (*size < 128) return -1;
1686
1687 size_t startIdx = 0;
1688 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
1689
1690 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1691 if (errChk == 0) return -2; //preamble not found
1692 if (*size != 128) return -3; //wrong size for fdxb
1693 //return start position
1694 return (int)startIdx;
1695 }
1696
1697 // by marshmellow
1698 // demod gProxIIDemod
1699 // error returns as -x
1700 // success returns start position in BitStream
1701 // BitStream must contain previously askrawdemod and biphasedemoded data
1702 int gProxII_Demod(uint8_t BitStream[], size_t *size) {
1703 size_t startIdx=0;
1704 uint8_t preamble[] = {1,1,1,1,1,0};
1705
1706 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
1707 if (errChk == 0) return -3; //preamble not found
1708 if (*size != 96) return -2; //should have found 96 bits
1709 //check first 6 spacer bits to verify format
1710 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
1711 //confirmed proper separator bits found
1712 //return start position
1713 return (int) startIdx;
1714 }
1715 return -5; //spacer bits not found - not a valid gproxII
1716 }
1717
1718 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
1719 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1720 if (justNoise(dest, *size)) return -1;
1721
1722 size_t numStart=0, size2=*size, startIdx=0;
1723 // FSK demodulator
1724 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1725 if (*size < 96*2) return -2;
1726 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1727 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
1728 // find bitstring in array
1729 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1730 if (errChk == 0) return -3; //preamble not found
1731
1732 numStart = startIdx + sizeof(preamble);
1733 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1734 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1735 if (dest[idx] == dest[idx+1]){
1736 return -4; //not manchester data
1737 }
1738 *hi2 = (*hi2<<1)|(*hi>>31);
1739 *hi = (*hi<<1)|(*lo>>31);
1740 //Then, shift in a 0 or one into low
1741 if (dest[idx] && !dest[idx+1]) // 1 0
1742 *lo=(*lo<<1)|1;
1743 else // 0 1
1744 *lo=(*lo<<1)|0;
1745 }
1746 return (int)startIdx;
1747 }
1748
1749 int IOdemodFSK(uint8_t *dest, size_t size) {
1750 if (justNoise(dest, size)) return -1;
1751 //make sure buffer has data
1752 if (size < 66*64) return -2;
1753 // FSK demodulator
1754 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
1755 if (size < 65) return -3; //did we get a good demod?
1756 //Index map
1757 //0 10 20 30 40 50 60
1758 //| | | | | | |
1759 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
1760 //-----------------------------------------------------------------------------
1761 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
1762 //
1763 //XSF(version)facility:codeone+codetwo
1764 //Handle the data
1765 size_t startIdx = 0;
1766 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
1767 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
1768 if (errChk == 0) return -4; //preamble not found
1769
1770 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
1771 //confirmed proper separator bits found
1772 //return start position
1773 return (int) startIdx;
1774 }
1775 return -5;
1776 }
1777
1778 // redesigned by marshmellow adjusted from existing decode functions
1779 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1780 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1781 //26 bit 40134 format (don't know other formats)
1782 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};
1783 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};
1784 size_t startidx = 0;
1785 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1786 // if didn't find preamble try again inverting
1787 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1788 *invert ^= 1;
1789 }
1790 if (*size != 64 && *size != 224) return -2;
1791 if (*invert==1)
1792 for (size_t i = startidx; i < *size + startidx; i++)
1793 bitStream[i] ^= 1;
1794
1795 return (int) startidx;
1796 }
1797
1798 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
1799 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1800 if (justNoise(dest, *size)) return -1;
1801
1802 size_t numStart=0, size2=*size, startIdx=0;
1803 // FSK demodulator
1804 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1805 if (*size < 96) return -2;
1806
1807 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1808 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
1809
1810 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1811 if (errChk == 0) return -3; //preamble not found
1812
1813 numStart = startIdx + sizeof(preamble);
1814 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1815 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1816 if (dest[idx] == dest[idx+1])
1817 return -4; //not manchester data
1818 *hi2 = (*hi2<<1)|(*hi>>31);
1819 *hi = (*hi<<1)|(*lo>>31);
1820 //Then, shift in a 0 or one into low
1821 if (dest[idx] && !dest[idx+1]) // 1 0
1822 *lo=(*lo<<1)|1;
1823 else // 0 1
1824 *lo=(*lo<<1)|0;
1825 }
1826 return (int)startIdx;
1827 }
1828
1829 // find presco preamble 0x10D in already demoded data
1830 int PrescoDemod(uint8_t *dest, size_t *size) {
1831 //make sure buffer has data
1832 if (*size < 64*2) return -2;
1833
1834 size_t startIdx = 0;
1835 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
1836 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1837 if (errChk == 0) return -4; //preamble not found
1838 //return start position
1839 return (int) startIdx;
1840 }
1841
1842 // by marshmellow
1843 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
1844 int PyramiddemodFSK(uint8_t *dest, size_t *size) {
1845 //make sure buffer has data
1846 if (*size < 128*50) return -5;
1847
1848 //test samples are not just noise
1849 if (justNoise(dest, *size)) return -1;
1850
1851 // FSK demodulator
1852 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1853 if (*size < 128) return -2; //did we get a good demod?
1854
1855 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
1856 size_t startIdx = 0;
1857 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1858 if (errChk == 0) return -4; //preamble not found
1859 if (*size != 128) return -3;
1860 return (int)startIdx;
1861 }
1862
1863 // by marshmellow
1864 // find viking preamble 0xF200 in already demoded data
1865 int VikingDemod_AM(uint8_t *dest, size_t *size) {
1866 //make sure buffer has data
1867 if (*size < 64*2) return -2;
1868
1869 size_t startIdx = 0;
1870 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};
1871 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1872 if (errChk == 0) return -4; //preamble not found
1873 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
1874 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
1875 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
1876 if ( checkCalc != 0xA8 ) return -5;
1877 if (*size != 64) return -6;
1878 //return start position
1879 return (int) startIdx;
1880 }
1881
1882 // by iceman
1883 // find Visa2000 preamble in already demoded data
1884 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1885 if (*size < 96) return -1; //make sure buffer has data
1886 size_t startIdx = 0;
1887 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};
1888 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1889 return -2; //preamble not found
1890 if (*size != 96) return -3; //wrong demoded size
1891 //return start position
1892 return (int)startIdx;
1893 }
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