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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 currently safe for
14 // device side use. (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, bool *strong) {
509 //find shortest transition from high to low
510 *strong = false;
511 size_t i = 0;
512 size_t transition1 = 0;
513 int lowestTransition = 255;
514 bool lastWasHigh = false;
515 size_t transitionSampleCount = 0;
516 //find first valid beginning of a high or low wave
517 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
518 ++i;
519 while ((dest[i] < peak && dest[i] > low) && (i < size))
520 ++i;
521 lastWasHigh = (dest[i] >= peak);
522
523 if (i==size) return 0;
524 transition1 = i;
525
526 for (;i < size; i++) {
527 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
528 lastWasHigh = (dest[i] >= peak);
529 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
530 transition1 = i;
531 } else if (dest[i] < peak && dest[i] > low) {
532 transitionSampleCount++;
533 }
534 }
535 if (lowestTransition == 255) lowestTransition = 0;
536 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
537 // if less than 10% of the samples were not peaks (or 90% were peaks) then we have a strong wave
538 if (transitionSampleCount / size < 10) {
539 *strong = true;
540 lowestTransition = getClosestClock(lowestTransition);
541 }
542 return lowestTransition;
543 }
544
545 //by marshmellow
546 //detect nrz clock by reading #peaks vs no peaks(or errors)
547 int DetectNRZClock(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
548 size_t i=0;
549 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
550 size_t loopCnt = 4096; //don't need to loop through entire array...
551 if (size == 0) return 0;
552 if (size<loopCnt) loopCnt = size-20;
553 //if we already have a valid clock quit
554 for (; i < 8; ++i)
555 if (clk[i] == clock) return clock;
556
557 //get high and low peak
558 int peak, low;
559 if (getHiLo(dest, loopCnt, &peak, &low, 90, 90) < 1) return 0;
560
561 bool strong = false;
562 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low, &strong);
563 if (strong) return lowestTransition;
564 size_t ii;
565 uint8_t clkCnt;
566 uint8_t tol = 0;
567 uint16_t smplCnt = 0;
568 int16_t peakcnt = 0;
569 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
570 uint16_t minPeak = 255;
571 bool firstpeak = true;
572 //test for large clipped waves - ignore first peak
573 for (i=0; i<loopCnt; i++) {
574 if (dest[i] >= peak || dest[i] <= low) {
575 if (firstpeak) continue;
576 smplCnt++;
577 } else {
578 firstpeak = false;
579 if (smplCnt > 0) {
580 if (minPeak > smplCnt && smplCnt > 7) minPeak = smplCnt;
581 peakcnt++;
582 if (g_debugMode == 2) prnt("DEBUG NRZ: minPeak: %d, smplCnt: %d, peakcnt: %d",minPeak,smplCnt,peakcnt);
583 smplCnt = 0;
584 }
585 }
586 }
587 if (minPeak < 8) return 0;
588 bool errBitHigh = 0;
589 bool bitHigh = 0;
590 uint8_t ignoreCnt = 0;
591 uint8_t ignoreWindow = 4;
592 bool lastPeakHigh = 0;
593 int lastBit = 0;
594 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
595 peakcnt=0;
596 //test each valid clock from smallest to greatest to see which lines up
597 for(clkCnt=0; clkCnt < 8; ++clkCnt) {
598 //ignore clocks smaller than smallest peak
599 if (clk[clkCnt] < minPeak - (clk[clkCnt]/4)) continue;
600 //try lining up the peaks by moving starting point (try first 256)
601 for (ii=20; ii < loopCnt; ++ii) {
602 if ((dest[ii] >= peak) || (dest[ii] <= low)) {
603 peakcnt = 0;
604 bitHigh = false;
605 ignoreCnt = 0;
606 lastBit = ii-clk[clkCnt];
607 //loop through to see if this start location works
608 for (i = ii; i < size-20; ++i) {
609 //if we are at a clock bit
610 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
611 //test high/low
612 if (dest[i] >= peak || dest[i] <= low) {
613 //if same peak don't count it
614 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
615 peakcnt++;
616 }
617 lastPeakHigh = (dest[i] >= peak);
618 bitHigh = true;
619 errBitHigh = false;
620 ignoreCnt = ignoreWindow;
621 lastBit += clk[clkCnt];
622 } else if (i == lastBit + clk[clkCnt] + tol) {
623 lastBit += clk[clkCnt];
624 }
625 //else if not a clock bit and no peaks
626 } else if (dest[i] < peak && dest[i] > low) {
627 if (ignoreCnt==0) {
628 bitHigh=false;
629 if (errBitHigh==true) peakcnt--;
630 errBitHigh=false;
631 } else {
632 ignoreCnt--;
633 }
634 // else if not a clock bit but we have a peak
635 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
636 //error bar found no clock...
637 errBitHigh=true;
638 }
639 }
640 if(peakcnt>peaksdet[clkCnt]) {
641 bestStart[clkCnt]=ii;
642 peaksdet[clkCnt]=peakcnt;
643 }
644 }
645 }
646 }
647 int iii=7;
648 uint8_t best=0;
649 for (iii=7; iii > 0; iii--) {
650 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
651 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
652 best = iii;
653 }
654 } else if (peaksdet[iii] > peaksdet[best]) {
655 best = iii;
656 }
657 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);
658 }
659 *clockStartIdx = bestStart[best];
660 return clk[best];
661 }
662
663 //by marshmellow
664 //countFC is to detect the field clock lengths.
665 //counts and returns the 2 most common wave lengths
666 //mainly used for FSK field clock detection
667 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) {
668 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
669 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
670 uint8_t fcLensFnd = 0;
671 uint8_t lastFCcnt = 0;
672 uint8_t fcCounter = 0;
673 size_t i;
674 if (size < 180) return 0;
675
676 // prime i to first up transition
677 for (i = 160; i < size-20; i++)
678 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
679 break;
680
681 for (; i < size-20; i++){
682 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
683 // new up transition
684 fcCounter++;
685 if (fskAdj){
686 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
687 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
688 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
689 if ((fcCounter==9) || fcCounter==4) fcCounter++;
690 // save last field clock count (fc/xx)
691 lastFCcnt = fcCounter;
692 }
693 // find which fcLens to save it to:
694 for (int ii=0; ii<15; ii++){
695 if (fcLens[ii]==fcCounter){
696 fcCnts[ii]++;
697 fcCounter=0;
698 break;
699 }
700 }
701 if (fcCounter>0 && fcLensFnd<15){
702 //add new fc length
703 fcCnts[fcLensFnd]++;
704 fcLens[fcLensFnd++]=fcCounter;
705 }
706 fcCounter=0;
707 } else {
708 // count sample
709 fcCounter++;
710 }
711 }
712
713 uint8_t best1=14, best2=14, best3=14;
714 uint16_t maxCnt1=0;
715 // go through fclens and find which ones are bigest 2
716 for (i=0; i<15; i++){
717 // get the 3 best FC values
718 if (fcCnts[i]>maxCnt1) {
719 best3=best2;
720 best2=best1;
721 maxCnt1=fcCnts[i];
722 best1=i;
723 } else if(fcCnts[i]>fcCnts[best2]){
724 best3=best2;
725 best2=i;
726 } else if(fcCnts[i]>fcCnts[best3]){
727 best3=i;
728 }
729 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]);
730 if (fcLens[i]==0) break;
731 }
732 if (fcLens[best1]==0) return 0;
733 uint8_t fcH=0, fcL=0;
734 if (fcLens[best1]>fcLens[best2]){
735 fcH=fcLens[best1];
736 fcL=fcLens[best2];
737 } else{
738 fcH=fcLens[best2];
739 fcL=fcLens[best1];
740 }
741 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
742 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]);
743 return 0; //lots of waves not psk or fsk
744 }
745 // TODO: take top 3 answers and compare to known Field clocks to get top 2
746
747 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
748 if (fskAdj) return fcs;
749 return (uint16_t)fcLens[best2] << 8 | fcLens[best1];
750 }
751
752 //by marshmellow
753 //detect psk clock by reading each phase shift
754 // a phase shift is determined by measuring the sample length of each wave
755 int DetectPSKClock(uint8_t dest[], size_t size, int clock, size_t *firstPhaseShift, uint8_t *curPhase, uint8_t *fc) {
756 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
757 uint16_t loopCnt = 4096; //don't need to loop through entire array...
758 if (size == 0) return 0;
759 if (size+3<loopCnt) loopCnt = size-20;
760
761 uint16_t fcs = countFC(dest, size, 0);
762 *fc = fcs & 0xFF;
763 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d, FC2: %d",*fc, fcs>>8);
764 if ((fcs>>8) == 10 && *fc == 8) return 0;
765 if (*fc!=2 && *fc!=4 && *fc!=8) return 0;
766
767 //if we already have a valid clock quit
768 size_t i=1;
769 for (; i < 8; ++i)
770 if (clk[i] == clock) return clock;
771
772 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
773
774 uint8_t clkCnt, tol=1;
775 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0, fullWaveLen=0;
776 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
777 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
778
779 //find start of modulating data in trace
780 i = findModStart(dest, size, *fc);
781
782 firstFullWave = pskFindFirstPhaseShift(dest, size, curPhase, i, *fc, &fullWaveLen);
783 if (firstFullWave == 0) {
784 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
785 // so skip a little to ensure we are past any Start Signal
786 firstFullWave = 160;
787 fullWaveLen = 0;
788 }
789
790 *firstPhaseShift = firstFullWave;
791 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
792 //test each valid clock from greatest to smallest to see which lines up
793 for(clkCnt=7; clkCnt >= 1 ; clkCnt--) {
794 tol = *fc/2;
795 lastClkBit = firstFullWave; //set end of wave as clock align
796 waveStart = 0;
797 errCnt=0;
798 peakcnt=0;
799 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
800
801 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
802 //top edge of wave = start of new wave
803 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
804 if (waveStart == 0) {
805 waveStart = i+1;
806 waveLenCnt=0;
807 } else { //waveEnd
808 waveEnd = i+1;
809 waveLenCnt = waveEnd-waveStart;
810 if (waveLenCnt > *fc){
811 //if this wave is a phase shift
812 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);
813 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
814 peakcnt++;
815 lastClkBit+=clk[clkCnt];
816 } else if (i<lastClkBit+8){
817 //noise after a phase shift - ignore
818 } else { //phase shift before supposed to based on clock
819 errCnt++;
820 }
821 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + *fc){
822 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
823 }
824 waveStart=i+1;
825 }
826 }
827 }
828 if (errCnt == 0){
829 return clk[clkCnt];
830 }
831 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
832 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
833 }
834 //all tested with errors
835 //return the highest clk with the most peaks found
836 uint8_t best=7;
837 for (i=7; i>=1; i--){
838 if (peaksdet[i] > peaksdet[best]) {
839 best = i;
840 }
841 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
842 }
843 return clk[best];
844 }
845
846 //by marshmellow
847 //detects the bit clock for FSK given the high and low Field Clocks
848 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
849 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
850 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
851 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
852 uint8_t rfLensFnd = 0;
853 uint8_t lastFCcnt = 0;
854 uint16_t fcCounter = 0;
855 uint16_t rfCounter = 0;
856 uint8_t firstBitFnd = 0;
857 size_t i;
858 if (size == 0) return 0;
859
860 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
861 rfLensFnd=0;
862 fcCounter=0;
863 rfCounter=0;
864 firstBitFnd=0;
865 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
866 // prime i to first peak / up transition
867 for (i = 160; i < size-20; i++)
868 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
869 break;
870
871 for (; i < size-20; i++){
872 fcCounter++;
873 rfCounter++;
874
875 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
876 continue;
877 // else new peak
878 // if we got less than the small fc + tolerance then set it to the small fc
879 // if it is inbetween set it to the last counter
880 if (fcCounter < fcHigh && fcCounter > fcLow)
881 fcCounter = lastFCcnt;
882 else if (fcCounter < fcLow+fcTol)
883 fcCounter = fcLow;
884 else //set it to the large fc
885 fcCounter = fcHigh;
886
887 //look for bit clock (rf/xx)
888 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
889 //not the same size as the last wave - start of new bit sequence
890 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
891 for (int ii=0; ii<15; ii++){
892 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
893 rfCnts[ii]++;
894 rfCounter = 0;
895 break;
896 }
897 }
898 if (rfCounter > 0 && rfLensFnd < 15){
899 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
900 rfCnts[rfLensFnd]++;
901 rfLens[rfLensFnd++] = rfCounter;
902 }
903 } else {
904 *firstClockEdge = i;
905 firstBitFnd++;
906 }
907 rfCounter=0;
908 lastFCcnt=fcCounter;
909 }
910 fcCounter=0;
911 }
912 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
913
914 for (i=0; i<15; i++){
915 //get highest 2 RF values (might need to get more values to compare or compare all?)
916 if (rfCnts[i]>rfCnts[rfHighest]){
917 rfHighest3=rfHighest2;
918 rfHighest2=rfHighest;
919 rfHighest=i;
920 } else if(rfCnts[i]>rfCnts[rfHighest2]){
921 rfHighest3=rfHighest2;
922 rfHighest2=i;
923 } else if(rfCnts[i]>rfCnts[rfHighest3]){
924 rfHighest3=i;
925 }
926 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
927 }
928 // set allowed clock remainder tolerance to be 1 large field clock length+1
929 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
930 uint8_t tol1 = fcHigh+1;
931
932 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
933
934 // loop to find the highest clock that has a remainder less than the tolerance
935 // compare samples counted divided by
936 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
937 int ii=7;
938 for (; ii>=2; ii--){
939 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
940 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
941 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
942 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
943 break;
944 }
945 }
946 }
947 }
948
949 if (ii<2) return 0; // oops we went too far
950
951 return clk[ii];
952 }
953
954 //**********************************************************************************************
955 //--------------------Modulation Demods &/or Decoding Section-----------------------------------
956 //**********************************************************************************************
957
958 // 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...
959 bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, size_t *i) {
960 if (buffSize < *i+4) return false;
961
962 for (; *i < buffSize - 4; *i+=1) {
963 *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...
964 if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
965 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
966 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
967 if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
968 *stStopLoc = *i + 3;
969 return true;
970 }
971 }
972 }
973 }
974 }
975 return false;
976 }
977 //by marshmellow
978 //attempt to identify a Sequence Terminator in ASK modulated raw wave
979 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
980 size_t bufsize = *size;
981 //need to loop through all samples and identify our clock, look for the ST pattern
982 int clk = 0;
983 int tol = 0;
984 int j=0, high, low, skip=0, start=0, end=0, minClk=255;
985 size_t i = 0;
986 //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
987 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
988 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...
989 //size_t testsize = (bufsize < 512) ? bufsize : 512;
990 int phaseoff = 0;
991 high = low = 128;
992 memset(tmpbuff, 0, sizeof(tmpbuff));
993 memset(waveLen, 0, sizeof(waveLen));
994
995 if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
996 // set clock - might be able to get this externally and remove this work...
997 clk = getClosestClock(minClk);
998 // clock not found - ERROR
999 if (clk == 0) {
1000 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1001 return false;
1002 }
1003 *foundclock = clk;
1004
1005 tol = clk/8;
1006 if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
1007 // first ST not found - ERROR
1008 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1009 return false;
1010 } else {
1011 if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
1012 }
1013 if (waveLen[i+2] > clk*1+tol)
1014 phaseoff = 0;
1015 else
1016 phaseoff = clk/2;
1017
1018 // skip over the remainder of ST
1019 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1020
1021 // now do it again to find the end
1022 int dummy1 = 0;
1023 end = skip;
1024 i+=3;
1025 if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
1026 //didn't find second ST - ERROR
1027 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1028 return false;
1029 }
1030 end -= phaseoff;
1031 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);
1032 //now begin to trim out ST so we can use normal demod cmds
1033 start = skip;
1034 size_t datalen = end - start;
1035 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1036 if ( clk - (datalen % clk) <= clk/8) {
1037 // padd the amount off - could be problematic... but shouldn't happen often
1038 datalen += clk - (datalen % clk);
1039 } else if ( (datalen % clk) <= clk/8 ) {
1040 // padd the amount off - could be problematic... but shouldn't happen often
1041 datalen -= datalen % clk;
1042 } else {
1043 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1044 return false;
1045 }
1046 // if datalen is less than one t55xx block - ERROR
1047 if (datalen/clk < 8*4) {
1048 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1049 return false;
1050 }
1051 size_t dataloc = start;
1052 if (buffer[dataloc-(clk*4)-(clk/4)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1053 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1054 for ( i=0; i <= (clk/4); ++i ) {
1055 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1056 dataloc -= i;
1057 break;
1058 }
1059 }
1060 }
1061
1062 size_t newloc = 0;
1063 i=0;
1064 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1065 bool firstrun = true;
1066 // warning - overwriting buffer given with raw wave data with ST removed...
1067 while ( dataloc < bufsize-(clk/2) ) {
1068 //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)
1069 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+clk/4]<high && buffer[dataloc+clk/4]>low) {
1070 for(i=0; i < clk/2-tol; ++i) {
1071 buffer[dataloc+i] = high+5;
1072 }
1073 } //test for small spike outlier (high between two lows) in the case of very strong waves
1074 if (buffer[dataloc] > low && buffer[dataloc+clk/4] <= low) {
1075 for(i=0; i < clk/4; ++i) {
1076 buffer[dataloc+i] = buffer[dataloc+clk/4];
1077 }
1078 }
1079 if (firstrun) {
1080 *stend = dataloc;
1081 *ststart = dataloc-(clk*4);
1082 firstrun=false;
1083 }
1084 for (i=0; i<datalen; ++i) {
1085 if (i+newloc < bufsize) {
1086 if (i+newloc < dataloc)
1087 buffer[i+newloc] = buffer[dataloc];
1088
1089 dataloc++;
1090 }
1091 }
1092 newloc += i;
1093 //skip next ST - we just assume it will be there from now on...
1094 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1095 dataloc += clk*4;
1096 }
1097 *size = newloc;
1098 return true;
1099 }
1100
1101 //by marshmellow
1102 //take 11 10 01 11 00 and make 01100 ... miller decoding
1103 //check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
1104 //decodes miller encoded binary
1105 //NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
1106 int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
1107 if (*size < 16) return -1;
1108 uint16_t MaxBits = 512, errCnt = 0;
1109 size_t i, bitCnt=0;
1110 uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
1111 uint8_t halfClkErr = 0;
1112 //find alignment, needs 4 1s or 0s to properly align
1113 for (i=1; i < *size-1; i++) {
1114 alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
1115 curBit = BitStream[i];
1116 if (alignCnt == 4) break;
1117 }
1118 // for now error if alignment not found. later add option to run it with multiple offsets...
1119 if (alignCnt != 4) {
1120 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");
1121 return -1;
1122 }
1123 alignedIdx = (i-1) % 2;
1124 for (i=alignedIdx; i < *size-3; i+=2) {
1125 halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
1126 if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
1127 errCnt++;
1128 BitStream[bitCnt++] = 7;
1129 continue;
1130 }
1131 BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
1132
1133 if (bitCnt > MaxBits) break;
1134 }
1135 *size = bitCnt;
1136 return errCnt;
1137 }
1138
1139 //by marshmellow
1140 //take 01 or 10 = 1 and 11 or 00 = 0
1141 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
1142 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1143 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int *offset, int invert) {
1144 uint16_t bitnum = 0;
1145 uint16_t errCnt = 0;
1146 size_t i = *offset;
1147 uint16_t MaxBits=512;
1148 //if not enough samples - error
1149 if (*size < 51) return -1;
1150 //check for phase change faults - skip one sample if faulty
1151 uint8_t offsetA = 1, offsetB = 1;
1152 for (; i<48; i+=2){
1153 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
1154 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
1155 }
1156 if (!offsetA && offsetB) *offset+=1;
1157 for (i=*offset; i<*size-3; i+=2){
1158 //check for phase error
1159 if (BitStream[i+1]==BitStream[i+2]) {
1160 BitStream[bitnum++]=7;
1161 errCnt++;
1162 }
1163 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1164 BitStream[bitnum++]=1^invert;
1165 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1166 BitStream[bitnum++]=invert;
1167 } else {
1168 BitStream[bitnum++]=7;
1169 errCnt++;
1170 }
1171 if(bitnum>MaxBits) break;
1172 }
1173 *size=bitnum;
1174 return errCnt;
1175 }
1176
1177 //by marshmellow
1178 //take 10 and 01 and manchester decode
1179 //run through 2 times and take least errCnt
1180 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) {
1181 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
1182 size_t i, ii;
1183 uint16_t bestErr = 1000, bestRun = 0;
1184 if (*size < 16) return -1;
1185 //find correct start position [alignment]
1186 for (ii=0;ii<2;++ii){
1187 for (i=ii; i<*size-3; i+=2)
1188 if (BitStream[i]==BitStream[i+1])
1189 errCnt++;
1190
1191 if (bestErr>errCnt){
1192 bestErr=errCnt;
1193 bestRun=ii;
1194 }
1195 errCnt=0;
1196 }
1197 *alignPos=bestRun;
1198 //decode
1199 for (i=bestRun; i < *size-3; i+=2){
1200 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
1201 BitStream[bitnum++]=invert;
1202 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
1203 BitStream[bitnum++]=invert^1;
1204 } else {
1205 BitStream[bitnum++]=7;
1206 }
1207 if(bitnum>MaxBits) break;
1208 }
1209 *size=bitnum;
1210 return bestErr;
1211 }
1212
1213 //by marshmellow
1214 //demodulates strong heavily clipped samples
1215 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
1216 {
1217 *startIdx=0;
1218 size_t bitCnt=0, smplCnt=1, errCnt=0;
1219 bool waveHigh = (BinStream[0] >= high);
1220 for (size_t i=1; i < *size; i++){
1221 if (BinStream[i] >= high && waveHigh){
1222 smplCnt++;
1223 } else if (BinStream[i] <= low && !waveHigh){
1224 smplCnt++;
1225 } else { //transition
1226 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
1227 if (smplCnt > clk-(clk/4)-1) { //full clock
1228 if (smplCnt > clk + (clk/4)+1) { //too many samples
1229 errCnt++;
1230 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1231 BinStream[bitCnt++] = 7;
1232 } else if (waveHigh) {
1233 BinStream[bitCnt++] = invert;
1234 BinStream[bitCnt++] = invert;
1235 } else if (!waveHigh) {
1236 BinStream[bitCnt++] = invert ^ 1;
1237 BinStream[bitCnt++] = invert ^ 1;
1238 }
1239 if (*startIdx==0) *startIdx = i-clk;
1240 waveHigh = !waveHigh;
1241 smplCnt = 0;
1242 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
1243 if (waveHigh) {
1244 BinStream[bitCnt++] = invert;
1245 } else if (!waveHigh) {
1246 BinStream[bitCnt++] = invert ^ 1;
1247 }
1248 if (*startIdx==0) *startIdx = i-(clk/2);
1249 waveHigh = !waveHigh;
1250 smplCnt = 0;
1251 } else {
1252 smplCnt++;
1253 //transition bit oops
1254 }
1255 } else { //haven't hit new high or new low yet
1256 smplCnt++;
1257 }
1258 }
1259 }
1260 *size = bitCnt;
1261 return errCnt;
1262 }
1263
1264 //by marshmellow
1265 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
1266 int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
1267 if (*size==0) return -1;
1268 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
1269 if (*clk==0 || start < 0) return -3;
1270 if (*invert != 1) *invert = 0;
1271 if (amp==1) askAmp(BinStream, *size);
1272 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
1273
1274 //start pos from detect ask clock is 1/2 clock offset
1275 // NOTE: can be negative (demod assumes rest of wave was there)
1276 *startIdx = start - (*clk/2);
1277 uint8_t initLoopMax = 255;
1278 if (initLoopMax > *size) initLoopMax = *size;
1279 // Detect high and lows
1280 //25% clip in case highs and lows aren't clipped [marshmellow]
1281 int high, low;
1282 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
1283 return -2; //just noise
1284
1285 size_t errCnt = 0;
1286 // if clean clipped waves detected run alternate demod
1287 if (DetectCleanAskWave(BinStream, *size, high, low)) {
1288 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
1289 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
1290 if (askType) { //askman
1291 uint8_t alignPos = 0;
1292 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
1293 *startIdx += *clk/2 * alignPos;
1294 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
1295 return errCnt;
1296 } else { //askraw
1297 return errCnt;
1298 }
1299 }
1300 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
1301 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
1302
1303 int lastBit; //set first clock check - can go negative
1304 size_t i, bitnum = 0; //output counter
1305 uint8_t midBit = 0;
1306 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
1307 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
1308 size_t MaxBits = 3072; //max bits to collect
1309 lastBit = start - *clk;
1310
1311 for (i = start; i < *size; ++i) {
1312 if (i-lastBit >= *clk-tol){
1313 if (BinStream[i] >= high) {
1314 BinStream[bitnum++] = *invert;
1315 } else if (BinStream[i] <= low) {
1316 BinStream[bitnum++] = *invert ^ 1;
1317 } else if (i-lastBit >= *clk+tol) {
1318 if (bitnum > 0) {
1319 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1320 BinStream[bitnum++]=7;
1321 errCnt++;
1322 }
1323 } else { //in tolerance - looking for peak
1324 continue;
1325 }
1326 midBit = 0;
1327 lastBit += *clk;
1328 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
1329 if (BinStream[i] >= high) {
1330 BinStream[bitnum++] = *invert;
1331 } else if (BinStream[i] <= low) {
1332 BinStream[bitnum++] = *invert ^ 1;
1333 } else if (i-lastBit >= *clk/2+tol) {
1334 BinStream[bitnum] = BinStream[bitnum-1];
1335 bitnum++;
1336 } else { //in tolerance - looking for peak
1337 continue;
1338 }
1339 midBit = 1;
1340 }
1341 if (bitnum >= MaxBits) break;
1342 }
1343 *size = bitnum;
1344 return errCnt;
1345 }
1346
1347 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
1348 int start = 0;
1349 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
1350 }
1351
1352 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1353 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1354 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1355 if (justNoise(dest, *size)) return -1;
1356 size_t clkStartIdx = 0;
1357 *clk = DetectNRZClock(dest, *size, *clk, &clkStartIdx);
1358 if (*clk==0) return -2;
1359 size_t i, gLen = 4096;
1360 if (gLen>*size) gLen = *size-20;
1361 int high, low;
1362 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1363
1364 uint8_t bit=0;
1365 //convert wave samples to 1's and 0's
1366 for(i=20; i < *size-20; i++){
1367 if (dest[i] >= high) bit = 1;
1368 if (dest[i] <= low) bit = 0;
1369 dest[i] = bit;
1370 }
1371 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1372 size_t lastBit = 0;
1373 size_t numBits = 0;
1374 for(i=21; i < *size-20; i++) {
1375 //if transition detected or large number of same bits - store the passed bits
1376 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1377 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1378 numBits += (i - lastBit + (*clk/4)) / *clk;
1379 if (lastBit == 0) {
1380 *startIdx = i - (numBits * *clk);
1381 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1382 }
1383 lastBit = i-1;
1384 }
1385 }
1386 *size = numBits;
1387 return 0;
1388 }
1389
1390 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
1391 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1392 size_t last_transition = 0;
1393 size_t idx = 1;
1394 if (fchigh==0) fchigh=10;
1395 if (fclow==0) fclow=8;
1396 //set the threshold close to 0 (graph) or 128 std to avoid static
1397 size_t preLastSample = 0;
1398 size_t LastSample = 0;
1399 size_t currSample = 0;
1400 if ( size < 1024 ) return 0; // not enough samples
1401
1402 //find start of modulating data in trace
1403 idx = findModStart(dest, size, fchigh);
1404 // Need to threshold first sample
1405 if(dest[idx] < FSK_PSK_THRESHOLD) dest[0] = 0;
1406 else dest[0] = 1;
1407
1408 last_transition = idx;
1409 idx++;
1410 size_t numBits = 0;
1411 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
1412 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
1413 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
1414 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
1415 for(; idx < size; idx++) {
1416 // threshold current value
1417 if (dest[idx] < FSK_PSK_THRESHOLD) dest[idx] = 0;
1418 else dest[idx] = 1;
1419
1420 // Check for 0->1 transition
1421 if (dest[idx-1] < dest[idx]) {
1422 preLastSample = LastSample;
1423 LastSample = currSample;
1424 currSample = idx-last_transition;
1425 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
1426 //do nothing with extra garbage
1427 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
1428 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
1429 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
1430 dest[numBits-1]=1;
1431 }
1432 dest[numBits++]=1;
1433 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1434 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
1435 //do nothing with beginning garbage and reset.. should be rare..
1436 numBits = 0;
1437 } 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)
1438 dest[numBits++]=1;
1439 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1440 } else { //9+ = 10 sample waves (or 6+ = 7)
1441 dest[numBits++]=0;
1442 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
1443 }
1444 last_transition = idx;
1445 }
1446 }
1447 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
1448 }
1449
1450 //translate 11111100000 to 10
1451 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
1452 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1453 uint8_t lastval=dest[0];
1454 size_t idx=0;
1455 size_t numBits=0;
1456 uint32_t n=1;
1457 for( idx=1; idx < size; idx++) {
1458 n++;
1459 if (dest[idx]==lastval) continue; //skip until we hit a transition
1460
1461 //find out how many bits (n) we collected (use 1/2 clk tolerance)
1462 //if lastval was 1, we have a 1->0 crossing
1463 if (dest[idx-1]==1) {
1464 n = (n * fclow + rfLen/2) / rfLen;
1465 } else {// 0->1 crossing
1466 n = (n * fchigh + rfLen/2) / rfLen;
1467 }
1468 if (n == 0) n = 1;
1469
1470 //first transition - save startidx
1471 if (numBits == 0) {
1472 if (lastval == 1) { //high to low
1473 *startIdx += (fclow * idx) - (n*rfLen);
1474 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
1475 } else {
1476 *startIdx += (fchigh * idx) - (n*rfLen);
1477 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
1478 }
1479 }
1480
1481 //add to our destination the bits we collected
1482 memset(dest+numBits, dest[idx-1]^invert , n);
1483 numBits += n;
1484 n=0;
1485 lastval=dest[idx];
1486 }//end for
1487 // if valid extra bits at the end were all the same frequency - add them in
1488 if (n > rfLen/fchigh) {
1489 if (dest[idx-2]==1) {
1490 n = (n * fclow + rfLen/2) / rfLen;
1491 } else {
1492 n = (n * fchigh + rfLen/2) / rfLen;
1493 }
1494 memset(dest+numBits, dest[idx-1]^invert , n);
1495 numBits += n;
1496 }
1497 return numBits;
1498 }
1499
1500 //by marshmellow (from holiman's base)
1501 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
1502 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1503 if (justNoise(dest, size)) return 0;
1504 // FSK demodulator
1505 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
1506 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
1507 return size;
1508 }
1509
1510 // by marshmellow
1511 // convert psk1 demod to psk2 demod
1512 // only transition waves are 1s
1513 void psk1TOpsk2(uint8_t *BitStream, size_t size) {
1514 size_t i=1;
1515 uint8_t lastBit=BitStream[0];
1516 for (; i<size; i++){
1517 if (BitStream[i]==7){
1518 //ignore errors
1519 } else if (lastBit!=BitStream[i]){
1520 lastBit=BitStream[i];
1521 BitStream[i]=1;
1522 } else {
1523 BitStream[i]=0;
1524 }
1525 }
1526 return;
1527 }
1528
1529 // by marshmellow
1530 // convert psk2 demod to psk1 demod
1531 // from only transition waves are 1s to phase shifts change bit
1532 void psk2TOpsk1(uint8_t *BitStream, size_t size) {
1533 uint8_t phase=0;
1534 for (size_t i=0; i<size; i++){
1535 if (BitStream[i]==1){
1536 phase ^=1;
1537 }
1538 BitStream[i]=phase;
1539 }
1540 return;
1541 }
1542
1543 //by marshmellow - demodulate PSK1 wave
1544 //uses wave lengths (# Samples)
1545 int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1546 if (*size < 170) return -1;
1547
1548 uint8_t curPhase = *invert;
1549 uint8_t fc=0;
1550 size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1551 uint16_t fullWaveLen=0, waveLenCnt=0, avgWaveVal;
1552 uint16_t errCnt=0, errCnt2=0;
1553
1554 *clock = DetectPSKClock(dest, *size, *clock, &firstFullWave, &curPhase, &fc);
1555 if (*clock <= 0) return -1;
1556 //if clock detect found firstfullwave...
1557 uint16_t tol = fc/2;
1558 if (firstFullWave == 0) {
1559 //find start of modulating data in trace
1560 i = findModStart(dest, *size, fc);
1561 //find first phase shift
1562 firstFullWave = pskFindFirstPhaseShift(dest, *size, &curPhase, i, fc, &fullWaveLen);
1563 if (firstFullWave == 0) {
1564 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1565 // so skip a little to ensure we are past any Start Signal
1566 firstFullWave = 160;
1567 memset(dest, curPhase, firstFullWave / *clock);
1568 } else {
1569 memset(dest, curPhase^1, firstFullWave / *clock);
1570 }
1571 } else {
1572 memset(dest, curPhase^1, firstFullWave / *clock);
1573 }
1574 //advance bits
1575 numBits += (firstFullWave / *clock);
1576 *startIdx = firstFullWave - (*clock * numBits)+2;
1577 //set start of wave as clock align
1578 lastClkBit = firstFullWave;
1579 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1580 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1581 waveStart = 0;
1582 dest[numBits++] = curPhase; //set first read bit
1583 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++) {
1584 //top edge of wave = start of new wave
1585 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]) {
1586 if (waveStart == 0) {
1587 waveStart = i+1;
1588 waveLenCnt = 0;
1589 avgWaveVal = dest[i+1];
1590 } else { //waveEnd
1591 waveEnd = i+1;
1592 waveLenCnt = waveEnd-waveStart;
1593 if (waveLenCnt > fc) {
1594 //this wave is a phase shift
1595 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1596 if (i+1 >= lastClkBit + *clock - tol) { //should be a clock bit
1597 curPhase ^= 1;
1598 dest[numBits++] = curPhase;
1599 lastClkBit += *clock;
1600 } else if (i < lastClkBit+10+fc) {
1601 //noise after a phase shift - ignore
1602 } else { //phase shift before supposed to based on clock
1603 errCnt++;
1604 dest[numBits++] = 7;
1605 }
1606 } else if (i+1 > lastClkBit + *clock + tol + fc) {
1607 lastClkBit += *clock; //no phase shift but clock bit
1608 dest[numBits++] = curPhase;
1609 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1610 errCnt2++;
1611 if(errCnt2 > 101) return errCnt2;
1612 avgWaveVal += dest[i+1];
1613 continue;
1614 }
1615 avgWaveVal = 0;
1616 waveStart = i+1;
1617 }
1618 }
1619 avgWaveVal += dest[i+1];
1620 }
1621 *size = numBits;
1622 return errCnt;
1623 }
1624
1625 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1626 int startIdx = 0;
1627 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
1628 }
1629
1630 //**********************************************************************************************
1631 //-----------------Tag format detection section-------------------------------------------------
1632 //**********************************************************************************************
1633
1634 // by marshmellow
1635 // FSK Demod then try to locate an AWID ID
1636 int AWIDdemodFSK(uint8_t *dest, size_t *size, int *waveStartIdx) {
1637 //make sure buffer has enough data
1638 if (*size < 96*50) return -1;
1639
1640 // FSK demodulator
1641 *size = fskdemod(dest, *size, 50, 1, 10, 8, waveStartIdx); // fsk2a RF/50
1642 if (*size < 96) return -3; //did we get a good demod?
1643
1644 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
1645 size_t startIdx = 0;
1646 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1647 if (errChk == 0) return -4; //preamble not found
1648 if (*size != 96) return -5;
1649 return (int)startIdx;
1650 }
1651
1652 //by marshmellow
1653 //takes 1s and 0s and searches for EM410x format - output EM ID
1654 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
1655 {
1656 //sanity checks
1657 if (*size < 64) return 0;
1658 if (BitStream[1]>1) return 0; //allow only 1s and 0s
1659
1660 // 111111111 bit pattern represent start of frame
1661 // include 0 in front to help get start pos
1662 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
1663 uint8_t errChk = 0;
1664 uint8_t FmtLen = 10; // sets of 4 bits = end data
1665 *startIdx = 0;
1666 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
1667 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
1668 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
1669
1670 //skip last 4bit parity row for simplicity
1671 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
1672 if (*size == 40) { // std em410x format
1673 *hi = 0;
1674 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
1675 } else if (*size == 88) { // long em format
1676 *hi = (bytebits_to_byte(BitStream, 24));
1677 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
1678 } else {
1679 if (g_debugMode) prnt("Error removing parity: %u", *size);
1680 return 0;
1681 }
1682 return 1;
1683 }
1684
1685 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
1686 // BitStream must contain previously askrawdemod and biphasedemoded data
1687 int FDXBdemodBI(uint8_t *dest, size_t *size) {
1688 //make sure buffer has enough data
1689 if (*size < 128) return -1;
1690
1691 size_t startIdx = 0;
1692 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
1693
1694 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1695 if (errChk == 0) return -2; //preamble not found
1696 if (*size != 128) return -3; //wrong size for fdxb
1697 //return start position
1698 return (int)startIdx;
1699 }
1700
1701 // by marshmellow
1702 // demod gProxIIDemod
1703 // error returns as -x
1704 // success returns start position in BitStream
1705 // BitStream must contain previously askrawdemod and biphasedemoded data
1706 int gProxII_Demod(uint8_t BitStream[], size_t *size) {
1707 size_t startIdx=0;
1708 uint8_t preamble[] = {1,1,1,1,1,0};
1709
1710 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
1711 if (errChk == 0) return -3; //preamble not found
1712 if (*size != 96) return -2; //should have found 96 bits
1713 //check first 6 spacer bits to verify format
1714 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
1715 //confirmed proper separator bits found
1716 //return start position
1717 return (int) startIdx;
1718 }
1719 return -5; //spacer bits not found - not a valid gproxII
1720 }
1721
1722 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
1723 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo, int *waveStartIdx) {
1724 size_t numStart=0, size2=*size, startIdx=0;
1725 // FSK demodulator fsk2a so invert and fc/10/8
1726 *size = fskdemod(dest, size2, 50, 1, 10, 8, waveStartIdx);
1727 if (*size < 96*2) return -2;
1728 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1729 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
1730 // find bitstring in array
1731 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1732 if (errChk == 0) return -3; //preamble not found
1733
1734 numStart = startIdx + sizeof(preamble);
1735 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1736 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1737 if (dest[idx] == dest[idx+1]){
1738 return -4; //not manchester data
1739 }
1740 *hi2 = (*hi2<<1)|(*hi>>31);
1741 *hi = (*hi<<1)|(*lo>>31);
1742 //Then, shift in a 0 or one into low
1743 if (dest[idx] && !dest[idx+1]) // 1 0
1744 *lo=(*lo<<1)|1;
1745 else // 0 1
1746 *lo=(*lo<<1)|0;
1747 }
1748 return (int)startIdx;
1749 }
1750
1751 int IOdemodFSK(uint8_t *dest, size_t size, int *waveStartIdx) {
1752 //make sure buffer has data
1753 if (size < 66*64) return -2;
1754 // FSK demodulator RF/64, fsk2a so invert, and fc/10/8
1755 size = fskdemod(dest, size, 64, 1, 10, 8, waveStartIdx);
1756 if (size < 65) return -3; //did we get a good demod?
1757 //Index map
1758 //0 10 20 30 40 50 60
1759 //| | | | | | |
1760 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
1761 //-----------------------------------------------------------------------------
1762 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
1763 //
1764 //XSF(version)facility:codeone+codetwo
1765 //Handle the data
1766 size_t startIdx = 0;
1767 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
1768 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
1769 if (errChk == 0) return -4; //preamble not found
1770
1771 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
1772 //confirmed proper separator bits found
1773 //return start position
1774 return (int) startIdx;
1775 }
1776 return -5;
1777 }
1778
1779 // redesigned by marshmellow adjusted from existing decode functions
1780 // indala id decoding
1781 int indala64decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1782 //standard 64 bit indala formats including 26 bit 40134 format
1783 uint8_t preamble64[] = {1,0,1,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 1};
1784 uint8_t preamble64_i[] = {0,1,0,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 0};
1785 size_t startidx = 0;
1786 size_t found_size = *size;
1787 bool found = preambleSearch(bitStream, preamble64, sizeof(preamble64), &found_size, &startidx);
1788 if (!found) {
1789 found = preambleSearch(bitStream, preamble64_i, sizeof(preamble64_i), &found_size, &startidx);
1790 if (!found) return -1;
1791 *invert ^= 1;
1792 }
1793 if (found_size != 64) return -2;
1794 if (*invert==1)
1795 for (size_t i = startidx; i < found_size + startidx; i++)
1796 bitStream[i] ^= 1;
1797
1798 // note: don't change *size until we are sure we got it...
1799 *size = found_size;
1800 return (int) startidx;
1801 }
1802
1803 int indala224decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1804 //large 224 bit indala formats (different preamble too...)
1805 uint8_t preamble224[] = {1,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,0, 0,0,0,1};
1806 uint8_t preamble224_i[] = {0,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,1, 1,1,1,0};
1807 size_t startidx = 0;
1808 size_t found_size = *size;
1809 bool found = preambleSearch(bitStream, preamble224, sizeof(preamble224), &found_size, &startidx);
1810 if (!found) {
1811 found = preambleSearch(bitStream, preamble224_i, sizeof(preamble224_i), &found_size, &startidx);
1812 if (!found) return -1;
1813 *invert ^= 1;
1814 }
1815 if (found_size != 224) return -2;
1816 if (*invert==1 && startidx > 0)
1817 for (size_t i = startidx-1; i < found_size + startidx + 2; i++)
1818 bitStream[i] ^= 1;
1819
1820 // 224 formats are typically PSK2 (afaik 2017 Marshmellow)
1821 // note loses 1 bit at beginning of transformation...
1822 // don't need to verify array is big enough as to get here there has to be a full preamble after all of our data
1823 psk1TOpsk2(bitStream + (startidx-1), found_size+2);
1824 startidx++;
1825
1826 *size = found_size;
1827 return (int) startidx;
1828 }
1829
1830 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
1831 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo, int *waveStartIdx) {
1832 size_t numStart=0, size2=*size, startIdx=0;
1833 // FSK demodulator
1834 *size = fskdemod(dest, size2,50,1,10,8,waveStartIdx); //fsk2a
1835 if (*size < 96) return -2;
1836
1837 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1838 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
1839
1840 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1841 if (errChk == 0) return -3; //preamble not found
1842
1843 numStart = startIdx + sizeof(preamble);
1844 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1845 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1846 if (dest[idx] == dest[idx+1])
1847 return -4; //not manchester data
1848 *hi2 = (*hi2<<1)|(*hi>>31);
1849 *hi = (*hi<<1)|(*lo>>31);
1850 //Then, shift in a 0 or one into low
1851 if (dest[idx] && !dest[idx+1]) // 1 0
1852 *lo=(*lo<<1)|1;
1853 else // 0 1
1854 *lo=(*lo<<1)|0;
1855 }
1856 return (int)startIdx;
1857 }
1858
1859 // find presco preamble 0x10D in already demoded data
1860 int PrescoDemod(uint8_t *dest, size_t *size) {
1861 //make sure buffer has data
1862 if (*size < 64*2) return -2;
1863
1864 size_t startIdx = 0;
1865 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
1866 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1867 if (errChk == 0) return -4; //preamble not found
1868 //return start position
1869 return (int) startIdx;
1870 }
1871
1872 // by marshmellow
1873 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
1874 int PyramiddemodFSK(uint8_t *dest, size_t *size, int *waveStartIdx) {
1875 //make sure buffer has data
1876 if (*size < 128*50) return -5;
1877
1878 // FSK demodulator
1879 *size = fskdemod(dest, *size, 50, 1, 10, 8, waveStartIdx); // fsk2a RF/50
1880 if (*size < 128) return -2; //did we get a good demod?
1881
1882 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
1883 size_t startIdx = 0;
1884 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1885 if (errChk == 0) return -4; //preamble not found
1886 if (*size != 128) return -3;
1887 return (int)startIdx;
1888 }
1889
1890 // by marshmellow
1891 // find viking preamble 0xF200 in already demoded data
1892 int VikingDemod_AM(uint8_t *dest, size_t *size) {
1893 //make sure buffer has data
1894 if (*size < 64*2) return -2;
1895
1896 size_t startIdx = 0;
1897 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};
1898 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1899 if (errChk == 0) return -4; //preamble not found
1900 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
1901 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
1902 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
1903 if ( checkCalc != 0xA8 ) return -5;
1904 if (*size != 64) return -6;
1905 //return start position
1906 return (int) startIdx;
1907 }
1908
1909 // by iceman
1910 // find Visa2000 preamble in already demoded data
1911 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1912 if (*size < 96) return -1; //make sure buffer has data
1913 size_t startIdx = 0;
1914 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};
1915 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1916 return -2; //preamble not found
1917 if (*size != 96) return -3; //wrong demoded size
1918 //return start position
1919 return (int)startIdx;
1920 }
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