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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 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 <stdint.h> // for uint_32+
37 #include <stdbool.h> // for bool
38
39 //**********************************************************************************************
40 //---------------------------------Utilities Section--------------------------------------------
41 //**********************************************************************************************
42 #define LOWEST_DEFAULT_CLOCK 32
43 //to allow debug print calls when used not on device
44 void dummy(char *fmt, ...){}
45 #ifndef ON_DEVICE
46 #include "ui.h"
47 #include "cmdparser.h"
48 #include "cmddata.h"
49 #define prnt PrintAndLog
50 #else
51 uint8_t g_debugMode=0;
52 #define prnt dummy
53 #endif
54
55 uint8_t justNoise(uint8_t *BitStream, size_t size) {
56 static const uint8_t THRESHOLD = 123;
57 //test samples are not just noise
58 uint8_t justNoise1 = 1;
59 for(size_t idx=0; idx < size && justNoise1 ;idx++){
60 justNoise1 = BitStream[idx] < THRESHOLD;
61 }
62 return justNoise1;
63 }
64
65 //by marshmellow
66 //get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
67 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) {
68 *high=0;
69 *low=255;
70 // get high and low thresholds
71 for (size_t i=0; i < size; i++){
72 if (BitStream[i] > *high) *high = BitStream[i];
73 if (BitStream[i] < *low) *low = BitStream[i];
74 }
75 if (*high < 123) return -1; // just noise
76 *high = ((*high-128)*fuzzHi + 12800)/100;
77 *low = ((*low-128)*fuzzLo + 12800)/100;
78 return 1;
79 }
80
81 // by marshmellow
82 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
83 // returns 1 if passed
84 uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
85 uint8_t ans = 0;
86 for (uint8_t i = 0; i < bitLen; i++){
87 ans ^= ((bits >> i) & 1);
88 }
89 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
90 return (ans == pType);
91 }
92
93 // by marshmellow
94 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
95 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
96 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) {
97 uint32_t parityWd = 0;
98 size_t j = 0, bitCnt = 0;
99 for (int word = 0; word < (bLen); word+=pLen) {
100 for (int bit=0; bit < pLen; bit++) {
101 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
102 BitStream[j++] = (BitStream[startIdx+word+bit]);
103 }
104 if (word+pLen > bLen) break;
105
106 j--; // overwrite parity with next data
107 // if parity fails then return 0
108 switch (pType) {
109 case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
110 case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
111 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
112 }
113 bitCnt+=(pLen-1);
114 parityWd = 0;
115 }
116 // if we got here then all the parities passed
117 //return ID start index and size
118 return bitCnt;
119 }
120
121 // by marshmellow
122 // takes a array of binary values, length of bits per parity (includes parity bit),
123 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
124 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
125 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) {
126 uint32_t parityWd = 0;
127 size_t j = 0, bitCnt = 0;
128 for (int word = 0; word < sourceLen; word+=pLen-1) {
129 for (int bit=0; bit < pLen-1; bit++){
130 parityWd = (parityWd << 1) | BitSource[word+bit];
131 dest[j++] = (BitSource[word+bit]);
132 }
133 // if parity fails then return 0
134 switch (pType) {
135 case 3: dest[j++]=0; break; // marker bit which should be a 0
136 case 2: dest[j++]=1; break; // marker bit which should be a 1
137 default:
138 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
139 break;
140 }
141 bitCnt += pLen;
142 parityWd = 0;
143 }
144 // if we got here then all the parities passed
145 //return ID start index and size
146 return bitCnt;
147 }
148
149 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) {
150 uint32_t num = 0;
151 for(int i = 0 ; i < numbits ; i++)
152 {
153 num = (num << 1) | (*src);
154 src++;
155 }
156 return num;
157 }
158
159 //least significant bit first
160 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) {
161 uint32_t num = 0;
162 for(int i = 0 ; i < numbits ; i++)
163 {
164 num = (num << 1) | *(src + (numbits-(i+1)));
165 }
166 return num;
167 }
168
169 // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
170 // fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
171 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
172 // Sanity check. If preamble length is bigger than bitstream length.
173 if ( *size <= pLen ) return false;
174
175 uint8_t foundCnt = 0;
176 for (size_t idx = 0; idx < *size - pLen; idx++) {
177 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
178 //first index found
179 foundCnt++;
180 if (foundCnt == 1) {
181 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
182 *startIdx = idx;
183 if (findone) return true;
184 } else if (foundCnt == 2) {
185 *size = idx - *startIdx;
186 return true;
187 }
188 }
189 }
190 return false;
191 }
192
193 //by marshmellow
194 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
195 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) {
196 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
197 }
198
199 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
200 size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
201 size_t i = 0;
202 size_t waveSizeCnt = 0;
203 uint8_t thresholdCnt = 0;
204 bool isAboveThreshold = dest[i++] >= threshold_value;
205 for (; i < size-20; i++ ) {
206 if(dest[i] < threshold_value && isAboveThreshold) {
207 thresholdCnt++;
208 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
209 isAboveThreshold = false;
210 waveSizeCnt = 0;
211 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
212 thresholdCnt++;
213 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
214 isAboveThreshold = true;
215 waveSizeCnt = 0;
216 } else {
217 waveSizeCnt++;
218 }
219 if (thresholdCnt > 10) break;
220 }
221 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
222 return i;
223 }
224
225 int getClosestClock(int testclk) {
226 uint8_t fndClk[] = {8,16,32,40,50,64,128};
227
228 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++)
229 if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1)
230 return fndClk[clkCnt];
231
232 return 0;
233 }
234
235 void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) {
236 while ((samples[*i] > low) && (*i < size))
237 *i+=1;
238 }
239
240 void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) {
241 while ((samples[*i] < high) && (*i < size))
242 *i+=1;
243 }
244
245 // load wave counters
246 bool loadWaveCounters(uint8_t samples[], size_t size, int lowToLowWaveLen[], int highToLowWaveLen[], int *waveCnt, int *skip, int *minClk, int *high, int *low) {
247 size_t i=0, firstLow, firstHigh;
248 size_t testsize = (size < 512) ? size : 512;
249
250 if ( getHiLo(samples, testsize, high, low, 80, 80) == -1 ) {
251 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
252 return false; //just noise
253 }
254
255 // get to first full low to prime loop and skip incomplete first pulse
256 getNextHigh(samples, size, *high, &i);
257 getNextLow(samples, size, *low, &i);
258 *skip = i;
259
260 // populate tmpbuff buffer with pulse lengths
261 while (i < size) {
262 // measure from low to low
263 firstLow = i;
264 //find first high point for this wave
265 getNextHigh(samples, size, *high, &i);
266 firstHigh = i;
267
268 getNextLow(samples, size, *low, &i);
269
270 if (*waveCnt >= (size/LOWEST_DEFAULT_CLOCK))
271 break;
272
273 highToLowWaveLen[*waveCnt] = i - firstHigh; //first high to first low
274 lowToLowWaveLen[*waveCnt] = i - firstLow;
275 *waveCnt += 1;
276 if (i-firstLow < *minClk && i < size) {
277 *minClk = i - firstLow;
278 }
279 }
280 return true;
281 }
282
283 //by marshmellow
284 //amplify based on ask edge detection - not accurate enough to use all the time
285 void askAmp(uint8_t *BitStream, size_t size) {
286 uint8_t Last = 128;
287 for(size_t i = 1; i<size; i++){
288 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
289 Last = 255;
290 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
291 Last = 0;
292
293 BitStream[i-1] = Last;
294 }
295 return;
296 }
297
298 uint32_t manchesterEncode2Bytes(uint16_t datain) {
299 uint32_t output = 0;
300 uint8_t curBit = 0;
301 for (uint8_t i=0; i<16; i++) {
302 curBit = (datain >> (15-i) & 1);
303 output |= (1<<(((15-i)*2)+curBit));
304 }
305 return output;
306 }
307
308 //by marshmellow
309 //encode binary data into binary manchester
310 //NOTE: BitStream must have double the size available in memory to do the swap
311 int ManchesterEncode(uint8_t *BitStream, size_t size) {
312 size_t modIdx=size, i=0;
313 if (size>modIdx) return -1;
314 for (size_t idx=0; idx < size; idx++){
315 BitStream[idx+modIdx++] = BitStream[idx];
316 BitStream[idx+modIdx++] = BitStream[idx]^1;
317 }
318 for (; i<(size*2); i++){
319 BitStream[i] = BitStream[i+size];
320 }
321 return i;
322 }
323
324 // by marshmellow
325 // to detect a wave that has heavily clipped (clean) samples
326 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) {
327 bool allArePeaks = true;
328 uint16_t cntPeaks=0;
329 size_t loopEnd = 512+160;
330 if (loopEnd > size) loopEnd = size;
331 for (size_t i=160; i<loopEnd; i++){
332 if (dest[i]>low && dest[i]<high)
333 allArePeaks = false;
334 else
335 cntPeaks++;
336 }
337 if (!allArePeaks){
338 if (cntPeaks > 300) return true;
339 }
340 return allArePeaks;
341 }
342
343 //**********************************************************************************************
344 //-------------------Clock / Bitrate Detection Section------------------------------------------
345 //**********************************************************************************************
346
347 // by marshmellow
348 // to help detect clocks on heavily clipped samples
349 // based on count of low to low
350 int DetectStrongAskClock(uint8_t dest[], size_t size, int high, int low, int *clock) {
351 size_t startwave;
352 size_t i = 100;
353 size_t minClk = 255;
354 int shortestWaveIdx = 0;
355 // get to first full low to prime loop and skip incomplete first pulse
356 getNextHigh(dest, size, high, &i);
357 getNextLow(dest, size, low, &i);
358
359 // loop through all samples
360 while (i < size) {
361 // measure from low to low
362 startwave = i;
363
364 getNextHigh(dest, size, high, &i);
365 getNextLow(dest, size, low, &i);
366 //get minimum measured distance
367 if (i-startwave < minClk && i < size) {
368 minClk = i - startwave;
369 shortestWaveIdx = startwave;
370 }
371 }
372 // set clock
373 if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk);
374 *clock = getClosestClock(minClk);
375 if (*clock == 0)
376 return 0;
377
378 return shortestWaveIdx;
379 }
380
381 // by marshmellow
382 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
383 // maybe somehow adjust peak trimming value based on samples to fix?
384 // return start index of best starting position for that clock and return clock (by reference)
385 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) {
386 size_t i=1;
387 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
388 uint8_t clkEnd = 9;
389 uint8_t loopCnt = 255; //don't need to loop through entire array...
390 if (size <= loopCnt+60) return -1; //not enough samples
391 size -= 60; //sometimes there is a strange end wave - filter out this....
392 //if we already have a valid clock
393 uint8_t clockFnd=0;
394 for (;i<clkEnd;++i)
395 if (clk[i] == *clock) clockFnd = i;
396 //clock found but continue to find best startpos
397
398 //get high and low peak
399 int peak, low;
400 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
401
402 //test for large clean peaks
403 if (!clockFnd){
404 if (DetectCleanAskWave(dest, size, peak, low)==1){
405 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
406 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
407 if (ans > 0) {
408 return ans; //return shortest wave start position
409 }
410 }
411 }
412 uint8_t ii;
413 uint8_t clkCnt, tol = 0;
414 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
415 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
416 size_t errCnt = 0;
417 size_t arrLoc, loopEnd;
418
419 if (clockFnd>0) {
420 clkCnt = clockFnd;
421 clkEnd = clockFnd+1;
422 }
423 else clkCnt=1;
424
425 //test each valid clock from smallest to greatest to see which lines up
426 for(; clkCnt < clkEnd; clkCnt++){
427 if (clk[clkCnt] <= 32){
428 tol=1;
429 }else{
430 tol=0;
431 }
432 //if no errors allowed - keep start within the first clock
433 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
434 bestErr[clkCnt]=1000;
435 //try lining up the peaks by moving starting point (try first few clocks)
436 for (ii=0; ii < loopCnt; ii++){
437 if (dest[ii] < peak && dest[ii] > low) continue;
438
439 errCnt=0;
440 // now that we have the first one lined up test rest of wave array
441 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
442 for (i=0; i < loopEnd; ++i){
443 arrLoc = ii + (i * clk[clkCnt]);
444 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
445 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
446 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
447 }else{ //error no peak detected
448 errCnt++;
449 }
450 }
451 //if we found no errors then we can stop here and a low clock (common clocks)
452 // this is correct one - return this clock
453 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
454 if(errCnt==0 && clkCnt<7) {
455 if (!clockFnd) *clock = clk[clkCnt];
456 return ii;
457 }
458 //if we found errors see if it is lowest so far and save it as best run
459 if(errCnt<bestErr[clkCnt]){
460 bestErr[clkCnt]=errCnt;
461 bestStart[clkCnt]=ii;
462 }
463 }
464 }
465 uint8_t iii;
466 uint8_t best=0;
467 for (iii=1; iii<clkEnd; ++iii){
468 if (bestErr[iii] < bestErr[best]){
469 if (bestErr[iii] == 0) bestErr[iii]=1;
470 // current best bit to error ratio vs new bit to error ratio
471 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
472 best = iii;
473 }
474 }
475 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d",clk[iii],bestErr[iii],clk[best],bestStart[best]);
476 }
477 if (!clockFnd) *clock = clk[best];
478 return bestStart[best];
479 }
480
481 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
482 //find shortest transition from high to low
483 size_t i = 0;
484 size_t transition1 = 0;
485 int lowestTransition = 255;
486 bool lastWasHigh = false;
487
488 //find first valid beginning of a high or low wave
489 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
490 ++i;
491 while ((dest[i] < peak && dest[i] > low) && (i < size))
492 ++i;
493 lastWasHigh = (dest[i] >= peak);
494
495 if (i==size) return 0;
496 transition1 = i;
497
498 for (;i < size; i++) {
499 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
500 lastWasHigh = (dest[i] >= peak);
501 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
502 transition1 = i;
503 }
504 }
505 if (lowestTransition == 255) lowestTransition = 0;
506 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
507 return lowestTransition;
508 }
509
510 //by marshmellow
511 //detect nrz clock by reading #peaks vs no peaks(or errors)
512 int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
513 size_t i=0;
514 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
515 size_t loopCnt = 4096; //don't need to loop through entire array...
516 if (size == 0) return 0;
517 if (size<loopCnt) loopCnt = size-20;
518 //if we already have a valid clock quit
519 for (; i < 8; ++i)
520 if (clk[i] == clock) return clock;
521
522 //get high and low peak
523 int peak, low;
524 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
525
526 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
527 size_t ii;
528 uint8_t clkCnt;
529 uint8_t tol = 0;
530 uint16_t smplCnt = 0;
531 int16_t peakcnt = 0;
532 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
533 uint16_t maxPeak = 255;
534 bool firstpeak = false;
535 //test for large clipped waves
536 for (i=0; i<loopCnt; i++){
537 if (dest[i] >= peak || dest[i] <= low){
538 if (!firstpeak) continue;
539 smplCnt++;
540 } else {
541 firstpeak=true;
542 if (smplCnt > 6 ){
543 if (maxPeak > smplCnt){
544 maxPeak = smplCnt;
545 //prnt("maxPk: %d",maxPeak);
546 }
547 peakcnt++;
548 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
549 smplCnt=0;
550 }
551 }
552 }
553 bool errBitHigh = 0;
554 bool bitHigh = 0;
555 uint8_t ignoreCnt = 0;
556 uint8_t ignoreWindow = 4;
557 bool lastPeakHigh = 0;
558 int lastBit = 0;
559 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
560 peakcnt=0;
561 //test each valid clock from smallest to greatest to see which lines up
562 for(clkCnt=0; clkCnt < 8; ++clkCnt){
563 //ignore clocks smaller than smallest peak
564 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
565 //try lining up the peaks by moving starting point (try first 256)
566 for (ii=20; ii < loopCnt; ++ii){
567 if ((dest[ii] >= peak) || (dest[ii] <= low)){
568 peakcnt = 0;
569 bitHigh = false;
570 ignoreCnt = 0;
571 lastBit = ii-clk[clkCnt];
572 //loop through to see if this start location works
573 for (i = ii; i < size-20; ++i) {
574 //if we are at a clock bit
575 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
576 //test high/low
577 if (dest[i] >= peak || dest[i] <= low) {
578 //if same peak don't count it
579 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
580 peakcnt++;
581 }
582 lastPeakHigh = (dest[i] >= peak);
583 bitHigh = true;
584 errBitHigh = false;
585 ignoreCnt = ignoreWindow;
586 lastBit += clk[clkCnt];
587 } else if (i == lastBit + clk[clkCnt] + tol) {
588 lastBit += clk[clkCnt];
589 }
590 //else if not a clock bit and no peaks
591 } else if (dest[i] < peak && dest[i] > low){
592 if (ignoreCnt==0){
593 bitHigh=false;
594 if (errBitHigh==true) peakcnt--;
595 errBitHigh=false;
596 } else {
597 ignoreCnt--;
598 }
599 // else if not a clock bit but we have a peak
600 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
601 //error bar found no clock...
602 errBitHigh=true;
603 }
604 }
605 if(peakcnt>peaksdet[clkCnt]) {
606 bestStart[clkCnt]=ii;
607 peaksdet[clkCnt]=peakcnt;
608 }
609 }
610 }
611 }
612 int iii=7;
613 uint8_t best=0;
614 for (iii=7; iii > 0; iii--){
615 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
616 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
617 best = iii;
618 }
619 } else if (peaksdet[iii] > peaksdet[best]){
620 best = iii;
621 }
622 if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition);
623 }
624 *clockStartIdx = bestStart[best];
625 return clk[best];
626 }
627
628 int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
629 size_t bestStart=0;
630 return DetectNRZClock_ext(dest, size, clock, &bestStart);
631 }
632
633 //by marshmellow
634 //countFC is to detect the field clock lengths.
635 //counts and returns the 2 most common wave lengths
636 //mainly used for FSK field clock detection
637 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) {
638 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
639 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
640 uint8_t fcLensFnd = 0;
641 uint8_t lastFCcnt = 0;
642 uint8_t fcCounter = 0;
643 size_t i;
644 if (size < 180) return 0;
645
646 // prime i to first up transition
647 for (i = 160; i < size-20; i++)
648 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
649 break;
650
651 for (; i < size-20; i++){
652 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
653 // new up transition
654 fcCounter++;
655 if (fskAdj){
656 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
657 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
658 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
659 if ((fcCounter==9) || fcCounter==4) fcCounter++;
660 // save last field clock count (fc/xx)
661 lastFCcnt = fcCounter;
662 }
663 // find which fcLens to save it to:
664 for (int ii=0; ii<15; ii++){
665 if (fcLens[ii]==fcCounter){
666 fcCnts[ii]++;
667 fcCounter=0;
668 break;
669 }
670 }
671 if (fcCounter>0 && fcLensFnd<15){
672 //add new fc length
673 fcCnts[fcLensFnd]++;
674 fcLens[fcLensFnd++]=fcCounter;
675 }
676 fcCounter=0;
677 } else {
678 // count sample
679 fcCounter++;
680 }
681 }
682
683 uint8_t best1=14, best2=14, best3=14;
684 uint16_t maxCnt1=0;
685 // go through fclens and find which ones are bigest 2
686 for (i=0; i<15; i++){
687 // get the 3 best FC values
688 if (fcCnts[i]>maxCnt1) {
689 best3=best2;
690 best2=best1;
691 maxCnt1=fcCnts[i];
692 best1=i;
693 } else if(fcCnts[i]>fcCnts[best2]){
694 best3=best2;
695 best2=i;
696 } else if(fcCnts[i]>fcCnts[best3]){
697 best3=i;
698 }
699 if (g_debugMode==2) prnt("DEBUG countfc: FC %u, Cnt %u, best fc: %u, best2 fc: %u",fcLens[i],fcCnts[i],fcLens[best1],fcLens[best2]);
700 }
701 if (fcLens[best1]==0) return 0;
702 uint8_t fcH=0, fcL=0;
703 if (fcLens[best1]>fcLens[best2]){
704 fcH=fcLens[best1];
705 fcL=fcLens[best2];
706 } else{
707 fcH=fcLens[best2];
708 fcL=fcLens[best1];
709 }
710 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
711 if (g_debugMode==2) prnt("DEBUG countfc: fc is too large: %u > %u. Not psk or fsk",(size-180)/fcH/3,fcCnts[best1]+fcCnts[best2]);
712 return 0; //lots of waves not psk or fsk
713 }
714 // TODO: take top 3 answers and compare to known Field clocks to get top 2
715
716 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
717 if (fskAdj) return fcs;
718 return fcLens[best1];
719 }
720
721 //by marshmellow
722 //detect psk clock by reading each phase shift
723 // a phase shift is determined by measuring the sample length of each wave
724 int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
725 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
726 uint16_t loopCnt = 4096; //don't need to loop through entire array...
727 if (size == 0) return 0;
728 if (size<loopCnt) loopCnt = size-20;
729
730 //if we already have a valid clock quit
731 size_t i=1;
732 for (; i < 8; ++i)
733 if (clk[i] == clock) return clock;
734
735 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
736 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
737 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
738 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
739 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
740 fc = countFC(dest, size, 0);
741 if (fc!=2 && fc!=4 && fc!=8) return -1;
742 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
743
744 //find first full wave
745 for (i=160; i<loopCnt; i++){
746 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
747 if (waveStart == 0) {
748 waveStart = i+1;
749 //prnt("DEBUG: waveStart: %d",waveStart);
750 } else {
751 waveEnd = i+1;
752 //prnt("DEBUG: waveEnd: %d",waveEnd);
753 waveLenCnt = waveEnd-waveStart;
754 if (waveLenCnt > fc){
755 firstFullWave = waveStart;
756 fullWaveLen=waveLenCnt;
757 break;
758 }
759 waveStart=0;
760 }
761 }
762 }
763 *firstPhaseShift = firstFullWave;
764 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
765 //test each valid clock from greatest to smallest to see which lines up
766 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
767 lastClkBit = firstFullWave; //set end of wave as clock align
768 waveStart = 0;
769 errCnt=0;
770 peakcnt=0;
771 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
772
773 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
774 //top edge of wave = start of new wave
775 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
776 if (waveStart == 0) {
777 waveStart = i+1;
778 waveLenCnt=0;
779 } else { //waveEnd
780 waveEnd = i+1;
781 waveLenCnt = waveEnd-waveStart;
782 if (waveLenCnt > fc){
783 //if this wave is a phase shift
784 if (g_debugMode == 2) prnt("DEBUG PSK: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,i+1,fc);
785 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
786 peakcnt++;
787 lastClkBit+=clk[clkCnt];
788 } else if (i<lastClkBit+8){
789 //noise after a phase shift - ignore
790 } else { //phase shift before supposed to based on clock
791 errCnt++;
792 }
793 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
794 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
795 }
796 waveStart=i+1;
797 }
798 }
799 }
800 if (errCnt == 0){
801 return clk[clkCnt];
802 }
803 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
804 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
805 }
806 //all tested with errors
807 //return the highest clk with the most peaks found
808 uint8_t best=7;
809 for (i=7; i>=1; i--){
810 if (peaksdet[i] > peaksdet[best]) {
811 best = i;
812 }
813 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
814 }
815 return clk[best];
816 }
817
818 int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
819 int firstPhaseShift = 0;
820 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
821 }
822
823 //by marshmellow
824 //detects the bit clock for FSK given the high and low Field Clocks
825 uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
826 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
827 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
828 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
829 uint8_t rfLensFnd = 0;
830 uint8_t lastFCcnt = 0;
831 uint16_t fcCounter = 0;
832 uint16_t rfCounter = 0;
833 uint8_t firstBitFnd = 0;
834 size_t i;
835 if (size == 0) return 0;
836
837 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
838 rfLensFnd=0;
839 fcCounter=0;
840 rfCounter=0;
841 firstBitFnd=0;
842 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
843 // prime i to first peak / up transition
844 for (i = 160; i < size-20; i++)
845 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
846 break;
847
848 for (; i < size-20; i++){
849 fcCounter++;
850 rfCounter++;
851
852 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
853 continue;
854 // else new peak
855 // if we got less than the small fc + tolerance then set it to the small fc
856 // if it is inbetween set it to the last counter
857 if (fcCounter < fcHigh && fcCounter > fcLow)
858 fcCounter = lastFCcnt;
859 else if (fcCounter < fcLow+fcTol)
860 fcCounter = fcLow;
861 else //set it to the large fc
862 fcCounter = fcHigh;
863
864 //look for bit clock (rf/xx)
865 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
866 //not the same size as the last wave - start of new bit sequence
867 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
868 for (int ii=0; ii<15; ii++){
869 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
870 rfCnts[ii]++;
871 rfCounter = 0;
872 break;
873 }
874 }
875 if (rfCounter > 0 && rfLensFnd < 15){
876 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
877 rfCnts[rfLensFnd]++;
878 rfLens[rfLensFnd++] = rfCounter;
879 }
880 } else {
881 *firstClockEdge = i;
882 firstBitFnd++;
883 }
884 rfCounter=0;
885 lastFCcnt=fcCounter;
886 }
887 fcCounter=0;
888 }
889 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
890
891 for (i=0; i<15; i++){
892 //get highest 2 RF values (might need to get more values to compare or compare all?)
893 if (rfCnts[i]>rfCnts[rfHighest]){
894 rfHighest3=rfHighest2;
895 rfHighest2=rfHighest;
896 rfHighest=i;
897 } else if(rfCnts[i]>rfCnts[rfHighest2]){
898 rfHighest3=rfHighest2;
899 rfHighest2=i;
900 } else if(rfCnts[i]>rfCnts[rfHighest3]){
901 rfHighest3=i;
902 }
903 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
904 }
905 // set allowed clock remainder tolerance to be 1 large field clock length+1
906 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
907 uint8_t tol1 = fcHigh+1;
908
909 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
910
911 // loop to find the highest clock that has a remainder less than the tolerance
912 // compare samples counted divided by
913 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
914 int ii=7;
915 for (; ii>=2; ii--){
916 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
917 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
918 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
919 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
920 break;
921 }
922 }
923 }
924 }
925
926 if (ii<2) return 0; // oops we went too far
927
928 return clk[ii];
929 }
930
931 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
932 int firstClockEdge = 0;
933 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
934 }
935
936 //**********************************************************************************************
937 //--------------------Modulation Demods &/or Decoding Section-----------------------------------
938 //**********************************************************************************************
939
940 // look for Sequence Terminator - should be pulses of clk*(1 or 2), clk*2, clk*(1.5 or 2), by idx we mean graph position index...
941 bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, size_t *i) {
942 for (; *i < buffSize - 4; *i+=1) {
943 *stStartIdx += lowToLowWaveLen[*i]; //caution part of this wave may be data and part may be ST.... to be accounted for in main function for now...
944 if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
945 if (lowToLowWaveLen[*i+1] >= clk*2-tol && lowToLowWaveLen[*i+1] <= clk*2+tol && highToLowWaveLen[*i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
946 if (lowToLowWaveLen[*i+2] >= (clk*3)/2-tol && lowToLowWaveLen[*i+2] <= clk*2+tol && highToLowWaveLen[*i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
947 if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
948 *stStopLoc = *i + 3;
949 return true;
950 }
951 }
952 }
953 }
954 }
955 return false;
956 }
957 //by marshmellow
958 //attempt to identify a Sequence Terminator in ASK modulated raw wave
959 bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
960 size_t bufsize = *size;
961 //need to loop through all samples and identify our clock, look for the ST pattern
962 int clk = 0;
963 int tol = 0;
964 int j, high, low, skip, start, end, minClk=255;
965 size_t i = 0;
966 //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
967 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
968 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...
969 //size_t testsize = (bufsize < 512) ? bufsize : 512;
970 int phaseoff = 0;
971 high = low = 128;
972 memset(tmpbuff, 0, sizeof(tmpbuff));
973 memset(waveLen, 0, sizeof(waveLen));
974
975 if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
976 // set clock - might be able to get this externally and remove this work...
977 clk = getClosestClock(minClk);
978 // clock not found - ERROR
979 if (clk == 0) {
980 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
981 return false;
982 }
983 *foundclock = clk;
984
985 tol = clk/8;
986 if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
987 // first ST not found - ERROR
988 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
989 return false;
990 } else {
991 if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
992 }
993 if (waveLen[i+2] > clk*1+tol)
994 phaseoff = 0;
995 else
996 phaseoff = clk/2;
997
998 // skip over the remainder of ST
999 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1000
1001 // now do it again to find the end
1002 int dummy1 = 0;
1003 end = skip;
1004 i+=3;
1005 if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
1006 //didn't find second ST - ERROR
1007 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1008 return false;
1009 }
1010 end -= phaseoff;
1011 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);
1012 //now begin to trim out ST so we can use normal demod cmds
1013 start = skip;
1014 size_t datalen = end - start;
1015 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1016 if ( clk - (datalen % clk) <= clk/8) {
1017 // padd the amount off - could be problematic... but shouldn't happen often
1018 datalen += clk - (datalen % clk);
1019 } else if ( (datalen % clk) <= clk/8 ) {
1020 // padd the amount off - could be problematic... but shouldn't happen often
1021 datalen -= datalen % clk;
1022 } else {
1023 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1024 return false;
1025 }
1026 // if datalen is less than one t55xx block - ERROR
1027 if (datalen/clk < 8*4) {
1028 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1029 return false;
1030 }
1031 size_t dataloc = start;
1032 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1033 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1034 for ( i=0; i <= (clk/8); ++i ) {
1035 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1036 dataloc -= i;
1037 break;
1038 }
1039 }
1040 }
1041
1042 size_t newloc = 0;
1043 i=0;
1044 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1045 bool firstrun = true;
1046 // warning - overwriting buffer given with raw wave data with ST removed...
1047 while ( dataloc < bufsize-(clk/2) ) {
1048 //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)
1049 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1050 for(i=0; i < clk/2-tol; ++i) {
1051 buffer[dataloc+i] = high+5;
1052 }
1053 } //test for single sample outlier (high between two lows) in the case of very strong waves
1054 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1055 buffer[dataloc] = buffer[dataloc+2];
1056 buffer[dataloc+1] = buffer[dataloc+2];
1057 }
1058 if (firstrun) {
1059 *stend = dataloc;
1060 *ststart = dataloc-(clk*4);
1061 firstrun=false;
1062 }
1063 for (i=0; i<datalen; ++i) {
1064 if (i+newloc < bufsize) {
1065 if (i+newloc < dataloc)
1066 buffer[i+newloc] = buffer[dataloc];
1067
1068 dataloc++;
1069 }
1070 }
1071 newloc += i;
1072 //skip next ST - we just assume it will be there from now on...
1073 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1074 dataloc += clk*4;
1075 }
1076 *size = newloc;
1077 return true;
1078 }
1079 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1080 size_t ststart = 0, stend = 0;
1081 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1082 }
1083
1084 //by marshmellow
1085 //take 11 10 01 11 00 and make 01100 ... miller decoding
1086 //check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
1087 //decodes miller encoded binary
1088 //NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
1089 int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
1090 if (*size < 16) return -1;
1091 uint16_t MaxBits = 512, errCnt = 0;
1092 size_t i, bitCnt=0;
1093 uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
1094 uint8_t halfClkErr = 0;
1095 //find alignment, needs 4 1s or 0s to properly align
1096 for (i=1; i < *size-1; i++) {
1097 alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
1098 curBit = BitStream[i];
1099 if (alignCnt == 4) break;
1100 }
1101 // for now error if alignment not found. later add option to run it with multiple offsets...
1102 if (alignCnt != 4) {
1103 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");
1104 return -1;
1105 }
1106 alignedIdx = (i-1) % 2;
1107 for (i=alignedIdx; i < *size-3; i+=2) {
1108 halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
1109 if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
1110 errCnt++;
1111 BitStream[bitCnt++] = 7;
1112 continue;
1113 }
1114 BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
1115
1116 if (bitCnt > MaxBits) break;
1117 }
1118 *size = bitCnt;
1119 return errCnt;
1120 }
1121
1122 //by marshmellow
1123 //take 01 or 10 = 1 and 11 or 00 = 0
1124 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
1125 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1126 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) {
1127 uint16_t bitnum = 0;
1128 uint16_t errCnt = 0;
1129 size_t i = offset;
1130 uint16_t MaxBits=512;
1131 //if not enough samples - error
1132 if (*size < 51) return -1;
1133 //check for phase change faults - skip one sample if faulty
1134 uint8_t offsetA = 1, offsetB = 1;
1135 for (; i<48; i+=2){
1136 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
1137 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
1138 }
1139 if (!offsetA && offsetB) offset++;
1140 for (i=offset; i<*size-3; i+=2){
1141 //check for phase error
1142 if (BitStream[i+1]==BitStream[i+2]) {
1143 BitStream[bitnum++]=7;
1144 errCnt++;
1145 }
1146 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1147 BitStream[bitnum++]=1^invert;
1148 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1149 BitStream[bitnum++]=invert;
1150 } else {
1151 BitStream[bitnum++]=7;
1152 errCnt++;
1153 }
1154 if(bitnum>MaxBits) break;
1155 }
1156 *size=bitnum;
1157 return errCnt;
1158 }
1159
1160 //by marshmellow
1161 //take 10 and 01 and manchester decode
1162 //run through 2 times and take least errCnt
1163 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) {
1164 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
1165 size_t i, ii;
1166 uint16_t bestErr = 1000, bestRun = 0;
1167 if (*size < 16) return -1;
1168 //find correct start position [alignment]
1169 for (ii=0;ii<2;++ii){
1170 for (i=ii; i<*size-3; i+=2)
1171 if (BitStream[i]==BitStream[i+1])
1172 errCnt++;
1173
1174 if (bestErr>errCnt){
1175 bestErr=errCnt;
1176 bestRun=ii;
1177 }
1178 errCnt=0;
1179 }
1180 *alignPos=bestRun;
1181 //decode
1182 for (i=bestRun; i < *size-3; i+=2){
1183 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
1184 BitStream[bitnum++]=invert;
1185 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
1186 BitStream[bitnum++]=invert^1;
1187 } else {
1188 BitStream[bitnum++]=7;
1189 }
1190 if(bitnum>MaxBits) break;
1191 }
1192 *size=bitnum;
1193 return bestErr;
1194 }
1195
1196 //by marshmellow
1197 //demodulates strong heavily clipped samples
1198 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
1199 {
1200 *startIdx=0;
1201 size_t bitCnt=0, smplCnt=1, errCnt=0;
1202 bool waveHigh = (BinStream[0] >= high);
1203 for (size_t i=1; i < *size; i++){
1204 if (BinStream[i] >= high && waveHigh){
1205 smplCnt++;
1206 } else if (BinStream[i] <= low && !waveHigh){
1207 smplCnt++;
1208 } else { //transition
1209 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
1210 if (smplCnt > clk-(clk/4)-1) { //full clock
1211 if (smplCnt > clk + (clk/4)+1) { //too many samples
1212 errCnt++;
1213 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1214 BinStream[bitCnt++] = 7;
1215 } else if (waveHigh) {
1216 BinStream[bitCnt++] = invert;
1217 BinStream[bitCnt++] = invert;
1218 } else if (!waveHigh) {
1219 BinStream[bitCnt++] = invert ^ 1;
1220 BinStream[bitCnt++] = invert ^ 1;
1221 }
1222 if (*startIdx==0) *startIdx = i-clk;
1223 waveHigh = !waveHigh;
1224 smplCnt = 0;
1225 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
1226 if (waveHigh) {
1227 BinStream[bitCnt++] = invert;
1228 } else if (!waveHigh) {
1229 BinStream[bitCnt++] = invert ^ 1;
1230 }
1231 if (*startIdx==0) *startIdx = i-(clk/2);
1232 waveHigh = !waveHigh;
1233 smplCnt = 0;
1234 } else {
1235 smplCnt++;
1236 //transition bit oops
1237 }
1238 } else { //haven't hit new high or new low yet
1239 smplCnt++;
1240 }
1241 }
1242 }
1243 *size = bitCnt;
1244 return errCnt;
1245 }
1246
1247 //by marshmellow
1248 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
1249 int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
1250 if (*size==0) return -1;
1251 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
1252 if (*clk==0 || start < 0) return -3;
1253 if (*invert != 1) *invert = 0;
1254 if (amp==1) askAmp(BinStream, *size);
1255 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
1256
1257 //start pos from detect ask clock is 1/2 clock offset
1258 // NOTE: can be negative (demod assumes rest of wave was there)
1259 *startIdx = start - (*clk/2);
1260 uint8_t initLoopMax = 255;
1261 if (initLoopMax > *size) initLoopMax = *size;
1262 // Detect high and lows
1263 //25% clip in case highs and lows aren't clipped [marshmellow]
1264 int high, low;
1265 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
1266 return -2; //just noise
1267
1268 size_t errCnt = 0;
1269 // if clean clipped waves detected run alternate demod
1270 if (DetectCleanAskWave(BinStream, *size, high, low)) {
1271 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
1272 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
1273 if (askType) { //askman
1274 uint8_t alignPos = 0;
1275 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
1276 *startIdx += *clk/2 * alignPos;
1277 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
1278 return errCnt;
1279 } else { //askraw
1280 return errCnt;
1281 }
1282 }
1283 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
1284 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
1285
1286 int lastBit; //set first clock check - can go negative
1287 size_t i, bitnum = 0; //output counter
1288 uint8_t midBit = 0;
1289 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
1290 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
1291 size_t MaxBits = 3072; //max bits to collect
1292 lastBit = start - *clk;
1293
1294 for (i = start; i < *size; ++i) {
1295 if (i-lastBit >= *clk-tol){
1296 if (BinStream[i] >= high) {
1297 BinStream[bitnum++] = *invert;
1298 } else if (BinStream[i] <= low) {
1299 BinStream[bitnum++] = *invert ^ 1;
1300 } else if (i-lastBit >= *clk+tol) {
1301 if (bitnum > 0) {
1302 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1303 BinStream[bitnum++]=7;
1304 errCnt++;
1305 }
1306 } else { //in tolerance - looking for peak
1307 continue;
1308 }
1309 midBit = 0;
1310 lastBit += *clk;
1311 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
1312 if (BinStream[i] >= high) {
1313 BinStream[bitnum++] = *invert;
1314 } else if (BinStream[i] <= low) {
1315 BinStream[bitnum++] = *invert ^ 1;
1316 } else if (i-lastBit >= *clk/2+tol) {
1317 BinStream[bitnum] = BinStream[bitnum-1];
1318 bitnum++;
1319 } else { //in tolerance - looking for peak
1320 continue;
1321 }
1322 midBit = 1;
1323 }
1324 if (bitnum >= MaxBits) break;
1325 }
1326 *size = bitnum;
1327 return errCnt;
1328 }
1329
1330 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
1331 int start = 0;
1332 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
1333 }
1334
1335 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1336 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1337 int nrzRawDemod_ext(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1338 if (justNoise(dest, *size)) return -1;
1339 *clk = DetectNRZClock(dest, *size, *clk);
1340 if (*clk==0) return -2;
1341 size_t i, gLen = 4096;
1342 if (gLen>*size) gLen = *size-20;
1343 int high, low;
1344 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1345
1346 uint8_t bit=0;
1347 //convert wave samples to 1's and 0's
1348 for(i=20; i < *size-20; i++){
1349 if (dest[i] >= high) bit = 1;
1350 if (dest[i] <= low) bit = 0;
1351 dest[i] = bit;
1352 }
1353 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1354 size_t lastBit = 0;
1355 size_t numBits = 0;
1356 for(i=21; i < *size-20; i++) {
1357 //if transition detected or large number of same bits - store the passed bits
1358 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1359 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1360 numBits += (i - lastBit + (*clk/4)) / *clk;
1361 if (lastBit == 0) {
1362 *startIdx = i - (numBits * *clk);
1363 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1364 }
1365 lastBit = i-1;
1366 }
1367 }
1368 *size = numBits;
1369 return 0;
1370 }
1371 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) {
1372 int startIdx = 0;
1373 return nrzRawDemod_ext(dest, size, clk, invert, &startIdx);
1374 }
1375
1376 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
1377 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1378 size_t last_transition = 0;
1379 size_t idx = 1;
1380 if (fchigh==0) fchigh=10;
1381 if (fclow==0) fclow=8;
1382 //set the threshold close to 0 (graph) or 128 std to avoid static
1383 uint8_t threshold_value = 123;
1384 size_t preLastSample = 0;
1385 size_t LastSample = 0;
1386 size_t currSample = 0;
1387 if ( size < 1024 ) return 0; // not enough samples
1388
1389 //find start of modulating data in trace
1390 idx = findModStart(dest, size, threshold_value, fchigh);
1391 // Need to threshold first sample
1392 if(dest[idx] < threshold_value) dest[0] = 0;
1393 else dest[0] = 1;
1394
1395 last_transition = idx;
1396 idx++;
1397 size_t numBits = 0;
1398 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
1399 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
1400 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
1401 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
1402 for(; idx < size; idx++) {
1403 // threshold current value
1404 if (dest[idx] < threshold_value) dest[idx] = 0;
1405 else dest[idx] = 1;
1406
1407 // Check for 0->1 transition
1408 if (dest[idx-1] < dest[idx]) {
1409 preLastSample = LastSample;
1410 LastSample = currSample;
1411 currSample = idx-last_transition;
1412 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
1413 //do nothing with extra garbage
1414 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
1415 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
1416 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
1417 dest[numBits-1]=1;
1418 }
1419 dest[numBits++]=1;
1420 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1421 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
1422 //do nothing with beginning garbage and reset.. should be rare..
1423 numBits = 0;
1424 } 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)
1425 dest[numBits++]=1;
1426 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1427 } else { //9+ = 10 sample waves (or 6+ = 7)
1428 dest[numBits++]=0;
1429 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
1430 }
1431 last_transition = idx;
1432 }
1433 }
1434 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
1435 }
1436
1437 //translate 11111100000 to 10
1438 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
1439 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1440 uint8_t lastval=dest[0];
1441 size_t idx=0;
1442 size_t numBits=0;
1443 uint32_t n=1;
1444 for( idx=1; idx < size; idx++) {
1445 n++;
1446 if (dest[idx]==lastval) continue; //skip until we hit a transition
1447
1448 //find out how many bits (n) we collected (use 1/2 clk tolerance)
1449 //if lastval was 1, we have a 1->0 crossing
1450 if (dest[idx-1]==1) {
1451 n = (n * fclow + rfLen/2) / rfLen;
1452 } else {// 0->1 crossing
1453 n = (n * fchigh + rfLen/2) / rfLen;
1454 }
1455 if (n == 0) n = 1;
1456
1457 //first transition - save startidx
1458 if (numBits == 0) {
1459 if (lastval == 1) { //high to low
1460 *startIdx += (fclow * idx) - (n*rfLen);
1461 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
1462 } else {
1463 *startIdx += (fchigh * idx) - (n*rfLen);
1464 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
1465 }
1466 }
1467
1468 //add to our destination the bits we collected
1469 memset(dest+numBits, dest[idx-1]^invert , n);
1470 numBits += n;
1471 n=0;
1472 lastval=dest[idx];
1473 }//end for
1474 // if valid extra bits at the end were all the same frequency - add them in
1475 if (n > rfLen/fchigh) {
1476 if (dest[idx-2]==1) {
1477 n = (n * fclow + rfLen/2) / rfLen;
1478 } else {
1479 n = (n * fchigh + rfLen/2) / rfLen;
1480 }
1481 memset(dest+numBits, dest[idx-1]^invert , n);
1482 numBits += n;
1483 }
1484 return numBits;
1485 }
1486
1487 //by marshmellow (from holiman's base)
1488 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
1489 int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1490 // FSK demodulator
1491 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
1492 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
1493 return size;
1494 }
1495
1496 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
1497 int startIdx=0;
1498 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
1499 }
1500
1501 // by marshmellow
1502 // convert psk1 demod to psk2 demod
1503 // only transition waves are 1s
1504 void psk1TOpsk2(uint8_t *BitStream, size_t size) {
1505 size_t i=1;
1506 uint8_t lastBit=BitStream[0];
1507 for (; i<size; i++){
1508 if (BitStream[i]==7){
1509 //ignore errors
1510 } else if (lastBit!=BitStream[i]){
1511 lastBit=BitStream[i];
1512 BitStream[i]=1;
1513 } else {
1514 BitStream[i]=0;
1515 }
1516 }
1517 return;
1518 }
1519
1520 // by marshmellow
1521 // convert psk2 demod to psk1 demod
1522 // from only transition waves are 1s to phase shifts change bit
1523 void psk2TOpsk1(uint8_t *BitStream, size_t size) {
1524 uint8_t phase=0;
1525 for (size_t i=0; i<size; i++){
1526 if (BitStream[i]==1){
1527 phase ^=1;
1528 }
1529 BitStream[i]=phase;
1530 }
1531 return;
1532 }
1533
1534 //by marshmellow - demodulate PSK1 wave
1535 //uses wave lengths (# Samples)
1536 int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1537 if (size == 0) return -1;
1538 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1539 if (*size<loopCnt) loopCnt = *size;
1540
1541 size_t numBits=0;
1542 uint8_t curPhase = *invert;
1543 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1544 uint16_t fc=0, fullWaveLen=0, tol=1;
1545 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1546 fc = countFC(dest, *size, 1);
1547 uint8_t fc2 = fc >> 8;
1548 if (fc2 == 10) return -1; //fsk found - quit
1549 fc = fc & 0xFF;
1550 if (fc!=2 && fc!=4 && fc!=8) return -1;
1551 //PrintAndLog("DEBUG: FC: %d",fc);
1552 *clock = DetectPSKClock(dest, *size, *clock);
1553 if (*clock == 0) return -1;
1554
1555 //find start of modulating data in trace
1556 uint8_t threshold_value = 123; //-5
1557 i = findModStart(dest, *size, threshold_value, fc);
1558
1559 //find first phase shift
1560 int avgWaveVal=0, lastAvgWaveVal=0;
1561 waveStart = i;
1562 for (; i<loopCnt; i++) {
1563 // find peak
1564 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1565 waveEnd = i+1;
1566 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1567 waveLenCnt = waveEnd-waveStart;
1568 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1569 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1570 firstFullWave = waveStart;
1571 fullWaveLen=waveLenCnt;
1572 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1573 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
1574 break;
1575 }
1576
1577 waveStart = i+1;
1578 avgWaveVal = 0;
1579 }
1580 avgWaveVal += dest[i+2];
1581 }
1582 if (firstFullWave == 0) {
1583 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1584 // so skip a little to ensure we are past any Start Signal
1585 firstFullWave = 160;
1586 memset(dest, curPhase, firstFullWave / *clock);
1587 } else {
1588 memset(dest, curPhase^1, firstFullWave / *clock);
1589 }
1590 //advance bits
1591 numBits += (firstFullWave / *clock);
1592 *startIdx = firstFullWave - (*clock * numBits)+2;
1593 //set start of wave as clock align
1594 lastClkBit = firstFullWave;
1595 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1596 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1597 waveStart = 0;
1598 dest[numBits++] = curPhase; //set first read bit
1599 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1600 //top edge of wave = start of new wave
1601 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1602 if (waveStart == 0) {
1603 waveStart = i+1;
1604 waveLenCnt = 0;
1605 avgWaveVal = dest[i+1];
1606 } else { //waveEnd
1607 waveEnd = i+1;
1608 waveLenCnt = waveEnd-waveStart;
1609 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1610 if (waveLenCnt > fc){
1611 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1612 //this wave is a phase shift
1613 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1614 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1615 curPhase ^= 1;
1616 dest[numBits++] = curPhase;
1617 lastClkBit += *clock;
1618 } else if (i < lastClkBit+10+fc){
1619 //noise after a phase shift - ignore
1620 } else { //phase shift before supposed to based on clock
1621 errCnt++;
1622 dest[numBits++] = 7;
1623 }
1624 } else if (i+1 > lastClkBit + *clock + tol + fc){
1625 lastClkBit += *clock; //no phase shift but clock bit
1626 dest[numBits++] = curPhase;
1627 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1628 errCnt2++;
1629 if(errCnt2 > 101) return errCnt2;
1630 }
1631 avgWaveVal = 0;
1632 waveStart = i+1;
1633 }
1634 }
1635 avgWaveVal += dest[i+1];
1636 }
1637 *size = numBits;
1638 return errCnt;
1639 }
1640
1641 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1642 int startIdx = 0;
1643 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
1644 }
1645
1646 //**********************************************************************************************
1647 //-----------------Tag format detection section-------------------------------------------------
1648 //**********************************************************************************************
1649
1650 // by marshmellow
1651 // FSK Demod then try to locate an AWID ID
1652 int AWIDdemodFSK(uint8_t *dest, size_t *size) {
1653 //make sure buffer has enough data
1654 if (*size < 96*50) return -1;
1655
1656 if (justNoise(dest, *size)) return -2;
1657
1658 // FSK demodulator
1659 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1660 if (*size < 96) return -3; //did we get a good demod?
1661
1662 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
1663 size_t startIdx = 0;
1664 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1665 if (errChk == 0) return -4; //preamble not found
1666 if (*size != 96) return -5;
1667 return (int)startIdx;
1668 }
1669
1670 //by marshmellow
1671 //takes 1s and 0s and searches for EM410x format - output EM ID
1672 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
1673 {
1674 //sanity checks
1675 if (*size < 64) return 0;
1676 if (BitStream[1]>1) return 0; //allow only 1s and 0s
1677
1678 // 111111111 bit pattern represent start of frame
1679 // include 0 in front to help get start pos
1680 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
1681 uint8_t errChk = 0;
1682 uint8_t FmtLen = 10; // sets of 4 bits = end data
1683 *startIdx = 0;
1684 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
1685 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
1686 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
1687
1688 //skip last 4bit parity row for simplicity
1689 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
1690 if (*size == 40) { // std em410x format
1691 *hi = 0;
1692 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
1693 } else if (*size == 88) { // long em format
1694 *hi = (bytebits_to_byte(BitStream, 24));
1695 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
1696 } else {
1697 return 0;
1698 }
1699 return 1;
1700 }
1701
1702 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
1703 // BitStream must contain previously askrawdemod and biphasedemoded data
1704 int FDXBdemodBI(uint8_t *dest, size_t *size) {
1705 //make sure buffer has enough data
1706 if (*size < 128) return -1;
1707
1708 size_t startIdx = 0;
1709 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
1710
1711 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1712 if (errChk == 0) return -2; //preamble not found
1713 return (int)startIdx;
1714 }
1715
1716 // by marshmellow
1717 // demod gProxIIDemod
1718 // error returns as -x
1719 // success returns start position in BitStream
1720 // BitStream must contain previously askrawdemod and biphasedemoded data
1721 int gProxII_Demod(uint8_t BitStream[], size_t *size) {
1722 size_t startIdx=0;
1723 uint8_t preamble[] = {1,1,1,1,1,0};
1724
1725 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
1726 if (errChk == 0) return -3; //preamble not found
1727 if (*size != 96) return -2; //should have found 96 bits
1728 //check first 6 spacer bits to verify format
1729 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
1730 //confirmed proper separator bits found
1731 //return start position
1732 return (int) startIdx;
1733 }
1734 return -5; //spacer bits not found - not a valid gproxII
1735 }
1736
1737 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
1738 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1739 if (justNoise(dest, *size)) return -1;
1740
1741 size_t numStart=0, size2=*size, startIdx=0;
1742 // FSK demodulator
1743 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1744 if (*size < 96*2) return -2;
1745 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1746 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
1747 // find bitstring in array
1748 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1749 if (errChk == 0) return -3; //preamble not found
1750
1751 numStart = startIdx + sizeof(preamble);
1752 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1753 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1754 if (dest[idx] == dest[idx+1]){
1755 return -4; //not manchester data
1756 }
1757 *hi2 = (*hi2<<1)|(*hi>>31);
1758 *hi = (*hi<<1)|(*lo>>31);
1759 //Then, shift in a 0 or one into low
1760 if (dest[idx] && !dest[idx+1]) // 1 0
1761 *lo=(*lo<<1)|1;
1762 else // 0 1
1763 *lo=(*lo<<1)|0;
1764 }
1765 return (int)startIdx;
1766 }
1767
1768 int IOdemodFSK(uint8_t *dest, size_t size) {
1769 if (justNoise(dest, size)) return -1;
1770 //make sure buffer has data
1771 if (size < 66*64) return -2;
1772 // FSK demodulator
1773 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
1774 if (size < 65) return -3; //did we get a good demod?
1775 //Index map
1776 //0 10 20 30 40 50 60
1777 //| | | | | | |
1778 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
1779 //-----------------------------------------------------------------------------
1780 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
1781 //
1782 //XSF(version)facility:codeone+codetwo
1783 //Handle the data
1784 size_t startIdx = 0;
1785 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
1786 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
1787 if (errChk == 0) return -4; //preamble not found
1788
1789 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
1790 //confirmed proper separator bits found
1791 //return start position
1792 return (int) startIdx;
1793 }
1794 return -5;
1795 }
1796
1797 // redesigned by marshmellow adjusted from existing decode functions
1798 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1799 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1800 //26 bit 40134 format (don't know other formats)
1801 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};
1802 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};
1803 size_t startidx = 0;
1804 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1805 // if didn't find preamble try again inverting
1806 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1807 *invert ^= 1;
1808 }
1809 if (*size != 64 && *size != 224) return -2;
1810 if (*invert==1)
1811 for (size_t i = startidx; i < *size; i++)
1812 bitStream[i] ^= 1;
1813
1814 return (int) startidx;
1815 }
1816
1817 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
1818 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1819 if (justNoise(dest, *size)) return -1;
1820
1821 size_t numStart=0, size2=*size, startIdx=0;
1822 // FSK demodulator
1823 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1824 if (*size < 96) return -2;
1825
1826 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1827 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
1828
1829 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1830 if (errChk == 0) return -3; //preamble not found
1831
1832 numStart = startIdx + sizeof(preamble);
1833 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1834 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1835 if (dest[idx] == dest[idx+1])
1836 return -4; //not manchester data
1837 *hi2 = (*hi2<<1)|(*hi>>31);
1838 *hi = (*hi<<1)|(*lo>>31);
1839 //Then, shift in a 0 or one into low
1840 if (dest[idx] && !dest[idx+1]) // 1 0
1841 *lo=(*lo<<1)|1;
1842 else // 0 1
1843 *lo=(*lo<<1)|0;
1844 }
1845 return (int)startIdx;
1846 }
1847
1848 // find presco preamble 0x10D in already demoded data
1849 int PrescoDemod(uint8_t *dest, size_t *size) {
1850 //make sure buffer has data
1851 if (*size < 64*2) return -2;
1852
1853 size_t startIdx = 0;
1854 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
1855 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1856 if (errChk == 0) return -4; //preamble not found
1857 //return start position
1858 return (int) startIdx;
1859 }
1860
1861 // by marshmellow
1862 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
1863 int PyramiddemodFSK(uint8_t *dest, size_t *size) {
1864 //make sure buffer has data
1865 if (*size < 128*50) return -5;
1866
1867 //test samples are not just noise
1868 if (justNoise(dest, *size)) return -1;
1869
1870 // FSK demodulator
1871 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1872 if (*size < 128) return -2; //did we get a good demod?
1873
1874 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
1875 size_t startIdx = 0;
1876 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1877 if (errChk == 0) return -4; //preamble not found
1878 if (*size != 128) return -3;
1879 return (int)startIdx;
1880 }
1881
1882 // by marshmellow
1883 // find viking preamble 0xF200 in already demoded data
1884 int VikingDemod_AM(uint8_t *dest, size_t *size) {
1885 //make sure buffer has data
1886 if (*size < 64*2) return -2;
1887
1888 size_t startIdx = 0;
1889 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};
1890 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1891 if (errChk == 0) return -4; //preamble not found
1892 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
1893 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
1894 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
1895 if ( checkCalc != 0xA8 ) return -5;
1896 if (*size != 64) return -6;
1897 //return start position
1898 return (int) startIdx;
1899 }
1900
1901 // by iceman
1902 // find Visa2000 preamble in already demoded data
1903 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1904 if (*size < 96) return -1; //make sure buffer has data
1905 size_t startIdx = 0;
1906 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};
1907 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1908 return -2; //preamble not found
1909 if (*size != 96) return -3; //wrong demoded size
1910 //return start position
1911 return (int)startIdx;
1912 }
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