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refactor pskdemod - remove nrz.._ext
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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 #define FSK_PSK_THRESHOLD 123
44 //to allow debug print calls when used not on device
45 void dummy(char *fmt, ...){}
46 #ifndef ON_DEVICE
47 #include "ui.h"
48 #include "cmdparser.h"
49 #include "cmddata.h"
50 #define prnt PrintAndLog
51 #else
52 uint8_t g_debugMode=0;
53 #define prnt dummy
54 #endif
55
56 uint8_t justNoise(uint8_t *BitStream, size_t size) {
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] < FSK_PSK_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 < FSK_PSK_THRESHOLD) 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 expWaveSize) {
201 size_t i = 0;
202 size_t waveSizeCnt = 0;
203 uint8_t thresholdCnt = 0;
204 bool isAboveThreshold = dest[i++] >= FSK_PSK_THRESHOLD;
205 for (; i < size-20; i++ ) {
206 if(dest[i] < FSK_PSK_THRESHOLD && isAboveThreshold) {
207 thresholdCnt++;
208 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
209 isAboveThreshold = false;
210 waveSizeCnt = 0;
211 } else if (dest[i] >= FSK_PSK_THRESHOLD && !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(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 //by marshmellow
629 //countFC is to detect the field clock lengths.
630 //counts and returns the 2 most common wave lengths
631 //mainly used for FSK field clock detection
632 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) {
633 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
634 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
635 uint8_t fcLensFnd = 0;
636 uint8_t lastFCcnt = 0;
637 uint8_t fcCounter = 0;
638 size_t i;
639 if (size < 180) return 0;
640
641 // prime i to first up transition
642 for (i = 160; i < size-20; i++)
643 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
644 break;
645
646 for (; i < size-20; i++){
647 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
648 // new up transition
649 fcCounter++;
650 if (fskAdj){
651 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
652 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
653 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
654 if ((fcCounter==9) || fcCounter==4) fcCounter++;
655 // save last field clock count (fc/xx)
656 lastFCcnt = fcCounter;
657 }
658 // find which fcLens to save it to:
659 for (int ii=0; ii<15; ii++){
660 if (fcLens[ii]==fcCounter){
661 fcCnts[ii]++;
662 fcCounter=0;
663 break;
664 }
665 }
666 if (fcCounter>0 && fcLensFnd<15){
667 //add new fc length
668 fcCnts[fcLensFnd]++;
669 fcLens[fcLensFnd++]=fcCounter;
670 }
671 fcCounter=0;
672 } else {
673 // count sample
674 fcCounter++;
675 }
676 }
677
678 uint8_t best1=14, best2=14, best3=14;
679 uint16_t maxCnt1=0;
680 // go through fclens and find which ones are bigest 2
681 for (i=0; i<15; i++){
682 // get the 3 best FC values
683 if (fcCnts[i]>maxCnt1) {
684 best3=best2;
685 best2=best1;
686 maxCnt1=fcCnts[i];
687 best1=i;
688 } else if(fcCnts[i]>fcCnts[best2]){
689 best3=best2;
690 best2=i;
691 } else if(fcCnts[i]>fcCnts[best3]){
692 best3=i;
693 }
694 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]);
695 }
696 if (fcLens[best1]==0) return 0;
697 uint8_t fcH=0, fcL=0;
698 if (fcLens[best1]>fcLens[best2]){
699 fcH=fcLens[best1];
700 fcL=fcLens[best2];
701 } else{
702 fcH=fcLens[best2];
703 fcL=fcLens[best1];
704 }
705 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
706 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]);
707 return 0; //lots of waves not psk or fsk
708 }
709 // TODO: take top 3 answers and compare to known Field clocks to get top 2
710
711 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
712 if (fskAdj) return fcs;
713 return fcLens[best1];
714 }
715
716 //by marshmellow
717 //detect psk clock by reading each phase shift
718 // a phase shift is determined by measuring the sample length of each wave
719 int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
720 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
721 uint16_t loopCnt = 4096; //don't need to loop through entire array...
722 if (size == 0) return 0;
723 if (size<loopCnt) loopCnt = size-20;
724
725 //if we already have a valid clock quit
726 size_t i=1;
727 for (; i < 8; ++i)
728 if (clk[i] == clock) return clock;
729
730 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
731 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
732 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
733 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
734 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
735 fc = countFC(dest, size, 0);
736 if (fc!=2 && fc!=4 && fc!=8) return -1;
737 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
738
739 //find first full wave
740 for (i=160; i<loopCnt; i++){
741 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
742 if (waveStart == 0) {
743 waveStart = i+1;
744 //prnt("DEBUG: waveStart: %d",waveStart);
745 } else {
746 waveEnd = i+1;
747 //prnt("DEBUG: waveEnd: %d",waveEnd);
748 waveLenCnt = waveEnd-waveStart;
749 if (waveLenCnt > fc){
750 firstFullWave = waveStart;
751 fullWaveLen=waveLenCnt;
752 break;
753 }
754 waveStart=0;
755 }
756 }
757 }
758 *firstPhaseShift = firstFullWave;
759 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
760 //test each valid clock from greatest to smallest to see which lines up
761 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
762 lastClkBit = firstFullWave; //set end of wave as clock align
763 waveStart = 0;
764 errCnt=0;
765 peakcnt=0;
766 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
767
768 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
769 //top edge of wave = start of new wave
770 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
771 if (waveStart == 0) {
772 waveStart = i+1;
773 waveLenCnt=0;
774 } else { //waveEnd
775 waveEnd = i+1;
776 waveLenCnt = waveEnd-waveStart;
777 if (waveLenCnt > fc){
778 //if this wave is a phase shift
779 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);
780 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
781 peakcnt++;
782 lastClkBit+=clk[clkCnt];
783 } else if (i<lastClkBit+8){
784 //noise after a phase shift - ignore
785 } else { //phase shift before supposed to based on clock
786 errCnt++;
787 }
788 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
789 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
790 }
791 waveStart=i+1;
792 }
793 }
794 }
795 if (errCnt == 0){
796 return clk[clkCnt];
797 }
798 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
799 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
800 }
801 //all tested with errors
802 //return the highest clk with the most peaks found
803 uint8_t best=7;
804 for (i=7; i>=1; i--){
805 if (peaksdet[i] > peaksdet[best]) {
806 best = i;
807 }
808 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
809 }
810 return clk[best];
811 }
812
813 int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
814 int firstPhaseShift = 0;
815 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
816 }
817
818 //by marshmellow
819 //detects the bit clock for FSK given the high and low Field Clocks
820 uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
821 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
822 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
823 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
824 uint8_t rfLensFnd = 0;
825 uint8_t lastFCcnt = 0;
826 uint16_t fcCounter = 0;
827 uint16_t rfCounter = 0;
828 uint8_t firstBitFnd = 0;
829 size_t i;
830 if (size == 0) return 0;
831
832 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
833 rfLensFnd=0;
834 fcCounter=0;
835 rfCounter=0;
836 firstBitFnd=0;
837 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
838 // prime i to first peak / up transition
839 for (i = 160; i < size-20; i++)
840 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
841 break;
842
843 for (; i < size-20; i++){
844 fcCounter++;
845 rfCounter++;
846
847 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
848 continue;
849 // else new peak
850 // if we got less than the small fc + tolerance then set it to the small fc
851 // if it is inbetween set it to the last counter
852 if (fcCounter < fcHigh && fcCounter > fcLow)
853 fcCounter = lastFCcnt;
854 else if (fcCounter < fcLow+fcTol)
855 fcCounter = fcLow;
856 else //set it to the large fc
857 fcCounter = fcHigh;
858
859 //look for bit clock (rf/xx)
860 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
861 //not the same size as the last wave - start of new bit sequence
862 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
863 for (int ii=0; ii<15; ii++){
864 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
865 rfCnts[ii]++;
866 rfCounter = 0;
867 break;
868 }
869 }
870 if (rfCounter > 0 && rfLensFnd < 15){
871 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
872 rfCnts[rfLensFnd]++;
873 rfLens[rfLensFnd++] = rfCounter;
874 }
875 } else {
876 *firstClockEdge = i;
877 firstBitFnd++;
878 }
879 rfCounter=0;
880 lastFCcnt=fcCounter;
881 }
882 fcCounter=0;
883 }
884 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
885
886 for (i=0; i<15; i++){
887 //get highest 2 RF values (might need to get more values to compare or compare all?)
888 if (rfCnts[i]>rfCnts[rfHighest]){
889 rfHighest3=rfHighest2;
890 rfHighest2=rfHighest;
891 rfHighest=i;
892 } else if(rfCnts[i]>rfCnts[rfHighest2]){
893 rfHighest3=rfHighest2;
894 rfHighest2=i;
895 } else if(rfCnts[i]>rfCnts[rfHighest3]){
896 rfHighest3=i;
897 }
898 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
899 }
900 // set allowed clock remainder tolerance to be 1 large field clock length+1
901 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
902 uint8_t tol1 = fcHigh+1;
903
904 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
905
906 // loop to find the highest clock that has a remainder less than the tolerance
907 // compare samples counted divided by
908 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
909 int ii=7;
910 for (; ii>=2; ii--){
911 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
912 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
913 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
914 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
915 break;
916 }
917 }
918 }
919 }
920
921 if (ii<2) return 0; // oops we went too far
922
923 return clk[ii];
924 }
925
926 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
927 int firstClockEdge = 0;
928 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
929 }
930
931 //**********************************************************************************************
932 //--------------------Modulation Demods &/or Decoding Section-----------------------------------
933 //**********************************************************************************************
934
935 // 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...
936 bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, size_t *i) {
937 for (; *i < buffSize - 4; *i+=1) {
938 *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...
939 if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
940 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
941 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
942 if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
943 *stStopLoc = *i + 3;
944 return true;
945 }
946 }
947 }
948 }
949 }
950 return false;
951 }
952 //by marshmellow
953 //attempt to identify a Sequence Terminator in ASK modulated raw wave
954 bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
955 size_t bufsize = *size;
956 //need to loop through all samples and identify our clock, look for the ST pattern
957 int clk = 0;
958 int tol = 0;
959 int j, high, low, skip, start, end, minClk=255;
960 size_t i = 0;
961 //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
962 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
963 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...
964 //size_t testsize = (bufsize < 512) ? bufsize : 512;
965 int phaseoff = 0;
966 high = low = 128;
967 memset(tmpbuff, 0, sizeof(tmpbuff));
968 memset(waveLen, 0, sizeof(waveLen));
969
970 if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
971 // set clock - might be able to get this externally and remove this work...
972 clk = getClosestClock(minClk);
973 // clock not found - ERROR
974 if (clk == 0) {
975 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
976 return false;
977 }
978 *foundclock = clk;
979
980 tol = clk/8;
981 if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
982 // first ST not found - ERROR
983 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
984 return false;
985 } else {
986 if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
987 }
988 if (waveLen[i+2] > clk*1+tol)
989 phaseoff = 0;
990 else
991 phaseoff = clk/2;
992
993 // skip over the remainder of ST
994 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
995
996 // now do it again to find the end
997 int dummy1 = 0;
998 end = skip;
999 i+=3;
1000 if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
1001 //didn't find second ST - ERROR
1002 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1003 return false;
1004 }
1005 end -= phaseoff;
1006 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);
1007 //now begin to trim out ST so we can use normal demod cmds
1008 start = skip;
1009 size_t datalen = end - start;
1010 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1011 if ( clk - (datalen % clk) <= clk/8) {
1012 // padd the amount off - could be problematic... but shouldn't happen often
1013 datalen += clk - (datalen % clk);
1014 } else if ( (datalen % clk) <= clk/8 ) {
1015 // padd the amount off - could be problematic... but shouldn't happen often
1016 datalen -= datalen % clk;
1017 } else {
1018 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1019 return false;
1020 }
1021 // if datalen is less than one t55xx block - ERROR
1022 if (datalen/clk < 8*4) {
1023 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1024 return false;
1025 }
1026 size_t dataloc = start;
1027 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1028 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1029 for ( i=0; i <= (clk/8); ++i ) {
1030 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1031 dataloc -= i;
1032 break;
1033 }
1034 }
1035 }
1036
1037 size_t newloc = 0;
1038 i=0;
1039 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1040 bool firstrun = true;
1041 // warning - overwriting buffer given with raw wave data with ST removed...
1042 while ( dataloc < bufsize-(clk/2) ) {
1043 //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)
1044 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1045 for(i=0; i < clk/2-tol; ++i) {
1046 buffer[dataloc+i] = high+5;
1047 }
1048 } //test for single sample outlier (high between two lows) in the case of very strong waves
1049 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1050 buffer[dataloc] = buffer[dataloc+2];
1051 buffer[dataloc+1] = buffer[dataloc+2];
1052 }
1053 if (firstrun) {
1054 *stend = dataloc;
1055 *ststart = dataloc-(clk*4);
1056 firstrun=false;
1057 }
1058 for (i=0; i<datalen; ++i) {
1059 if (i+newloc < bufsize) {
1060 if (i+newloc < dataloc)
1061 buffer[i+newloc] = buffer[dataloc];
1062
1063 dataloc++;
1064 }
1065 }
1066 newloc += i;
1067 //skip next ST - we just assume it will be there from now on...
1068 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1069 dataloc += clk*4;
1070 }
1071 *size = newloc;
1072 return true;
1073 }
1074 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1075 size_t ststart = 0, stend = 0;
1076 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1077 }
1078
1079 //by marshmellow
1080 //take 11 10 01 11 00 and make 01100 ... miller decoding
1081 //check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
1082 //decodes miller encoded binary
1083 //NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
1084 int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
1085 if (*size < 16) return -1;
1086 uint16_t MaxBits = 512, errCnt = 0;
1087 size_t i, bitCnt=0;
1088 uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
1089 uint8_t halfClkErr = 0;
1090 //find alignment, needs 4 1s or 0s to properly align
1091 for (i=1; i < *size-1; i++) {
1092 alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
1093 curBit = BitStream[i];
1094 if (alignCnt == 4) break;
1095 }
1096 // for now error if alignment not found. later add option to run it with multiple offsets...
1097 if (alignCnt != 4) {
1098 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");
1099 return -1;
1100 }
1101 alignedIdx = (i-1) % 2;
1102 for (i=alignedIdx; i < *size-3; i+=2) {
1103 halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
1104 if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
1105 errCnt++;
1106 BitStream[bitCnt++] = 7;
1107 continue;
1108 }
1109 BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
1110
1111 if (bitCnt > MaxBits) break;
1112 }
1113 *size = bitCnt;
1114 return errCnt;
1115 }
1116
1117 //by marshmellow
1118 //take 01 or 10 = 1 and 11 or 00 = 0
1119 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
1120 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1121 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) {
1122 uint16_t bitnum = 0;
1123 uint16_t errCnt = 0;
1124 size_t i = offset;
1125 uint16_t MaxBits=512;
1126 //if not enough samples - error
1127 if (*size < 51) return -1;
1128 //check for phase change faults - skip one sample if faulty
1129 uint8_t offsetA = 1, offsetB = 1;
1130 for (; i<48; i+=2){
1131 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
1132 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
1133 }
1134 if (!offsetA && offsetB) offset++;
1135 for (i=offset; i<*size-3; i+=2){
1136 //check for phase error
1137 if (BitStream[i+1]==BitStream[i+2]) {
1138 BitStream[bitnum++]=7;
1139 errCnt++;
1140 }
1141 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1142 BitStream[bitnum++]=1^invert;
1143 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1144 BitStream[bitnum++]=invert;
1145 } else {
1146 BitStream[bitnum++]=7;
1147 errCnt++;
1148 }
1149 if(bitnum>MaxBits) break;
1150 }
1151 *size=bitnum;
1152 return errCnt;
1153 }
1154
1155 //by marshmellow
1156 //take 10 and 01 and manchester decode
1157 //run through 2 times and take least errCnt
1158 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) {
1159 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
1160 size_t i, ii;
1161 uint16_t bestErr = 1000, bestRun = 0;
1162 if (*size < 16) return -1;
1163 //find correct start position [alignment]
1164 for (ii=0;ii<2;++ii){
1165 for (i=ii; i<*size-3; i+=2)
1166 if (BitStream[i]==BitStream[i+1])
1167 errCnt++;
1168
1169 if (bestErr>errCnt){
1170 bestErr=errCnt;
1171 bestRun=ii;
1172 }
1173 errCnt=0;
1174 }
1175 *alignPos=bestRun;
1176 //decode
1177 for (i=bestRun; i < *size-3; i+=2){
1178 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
1179 BitStream[bitnum++]=invert;
1180 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
1181 BitStream[bitnum++]=invert^1;
1182 } else {
1183 BitStream[bitnum++]=7;
1184 }
1185 if(bitnum>MaxBits) break;
1186 }
1187 *size=bitnum;
1188 return bestErr;
1189 }
1190
1191 //by marshmellow
1192 //demodulates strong heavily clipped samples
1193 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
1194 {
1195 *startIdx=0;
1196 size_t bitCnt=0, smplCnt=1, errCnt=0;
1197 bool waveHigh = (BinStream[0] >= high);
1198 for (size_t i=1; i < *size; i++){
1199 if (BinStream[i] >= high && waveHigh){
1200 smplCnt++;
1201 } else if (BinStream[i] <= low && !waveHigh){
1202 smplCnt++;
1203 } else { //transition
1204 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
1205 if (smplCnt > clk-(clk/4)-1) { //full clock
1206 if (smplCnt > clk + (clk/4)+1) { //too many samples
1207 errCnt++;
1208 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1209 BinStream[bitCnt++] = 7;
1210 } else if (waveHigh) {
1211 BinStream[bitCnt++] = invert;
1212 BinStream[bitCnt++] = invert;
1213 } else if (!waveHigh) {
1214 BinStream[bitCnt++] = invert ^ 1;
1215 BinStream[bitCnt++] = invert ^ 1;
1216 }
1217 if (*startIdx==0) *startIdx = i-clk;
1218 waveHigh = !waveHigh;
1219 smplCnt = 0;
1220 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
1221 if (waveHigh) {
1222 BinStream[bitCnt++] = invert;
1223 } else if (!waveHigh) {
1224 BinStream[bitCnt++] = invert ^ 1;
1225 }
1226 if (*startIdx==0) *startIdx = i-(clk/2);
1227 waveHigh = !waveHigh;
1228 smplCnt = 0;
1229 } else {
1230 smplCnt++;
1231 //transition bit oops
1232 }
1233 } else { //haven't hit new high or new low yet
1234 smplCnt++;
1235 }
1236 }
1237 }
1238 *size = bitCnt;
1239 return errCnt;
1240 }
1241
1242 //by marshmellow
1243 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
1244 int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
1245 if (*size==0) return -1;
1246 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
1247 if (*clk==0 || start < 0) return -3;
1248 if (*invert != 1) *invert = 0;
1249 if (amp==1) askAmp(BinStream, *size);
1250 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
1251
1252 //start pos from detect ask clock is 1/2 clock offset
1253 // NOTE: can be negative (demod assumes rest of wave was there)
1254 *startIdx = start - (*clk/2);
1255 uint8_t initLoopMax = 255;
1256 if (initLoopMax > *size) initLoopMax = *size;
1257 // Detect high and lows
1258 //25% clip in case highs and lows aren't clipped [marshmellow]
1259 int high, low;
1260 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
1261 return -2; //just noise
1262
1263 size_t errCnt = 0;
1264 // if clean clipped waves detected run alternate demod
1265 if (DetectCleanAskWave(BinStream, *size, high, low)) {
1266 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
1267 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
1268 if (askType) { //askman
1269 uint8_t alignPos = 0;
1270 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
1271 *startIdx += *clk/2 * alignPos;
1272 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
1273 return errCnt;
1274 } else { //askraw
1275 return errCnt;
1276 }
1277 }
1278 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
1279 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
1280
1281 int lastBit; //set first clock check - can go negative
1282 size_t i, bitnum = 0; //output counter
1283 uint8_t midBit = 0;
1284 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
1285 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
1286 size_t MaxBits = 3072; //max bits to collect
1287 lastBit = start - *clk;
1288
1289 for (i = start; i < *size; ++i) {
1290 if (i-lastBit >= *clk-tol){
1291 if (BinStream[i] >= high) {
1292 BinStream[bitnum++] = *invert;
1293 } else if (BinStream[i] <= low) {
1294 BinStream[bitnum++] = *invert ^ 1;
1295 } else if (i-lastBit >= *clk+tol) {
1296 if (bitnum > 0) {
1297 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1298 BinStream[bitnum++]=7;
1299 errCnt++;
1300 }
1301 } else { //in tolerance - looking for peak
1302 continue;
1303 }
1304 midBit = 0;
1305 lastBit += *clk;
1306 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
1307 if (BinStream[i] >= high) {
1308 BinStream[bitnum++] = *invert;
1309 } else if (BinStream[i] <= low) {
1310 BinStream[bitnum++] = *invert ^ 1;
1311 } else if (i-lastBit >= *clk/2+tol) {
1312 BinStream[bitnum] = BinStream[bitnum-1];
1313 bitnum++;
1314 } else { //in tolerance - looking for peak
1315 continue;
1316 }
1317 midBit = 1;
1318 }
1319 if (bitnum >= MaxBits) break;
1320 }
1321 *size = bitnum;
1322 return errCnt;
1323 }
1324
1325 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
1326 int start = 0;
1327 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
1328 }
1329
1330 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1331 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1332 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1333 if (justNoise(dest, *size)) return -1;
1334 size_t clkStartIdx = 0;
1335 *clk = DetectNRZClock(dest, *size, *clk, &clkStartIdx);
1336 if (*clk==0) return -2;
1337 size_t i, gLen = 4096;
1338 if (gLen>*size) gLen = *size-20;
1339 int high, low;
1340 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1341
1342 uint8_t bit=0;
1343 //convert wave samples to 1's and 0's
1344 for(i=20; i < *size-20; i++){
1345 if (dest[i] >= high) bit = 1;
1346 if (dest[i] <= low) bit = 0;
1347 dest[i] = bit;
1348 }
1349 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1350 size_t lastBit = 0;
1351 size_t numBits = 0;
1352 for(i=21; i < *size-20; i++) {
1353 //if transition detected or large number of same bits - store the passed bits
1354 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1355 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1356 numBits += (i - lastBit + (*clk/4)) / *clk;
1357 if (lastBit == 0) {
1358 *startIdx = i - (numBits * *clk);
1359 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1360 }
1361 lastBit = i-1;
1362 }
1363 }
1364 *size = numBits;
1365 return 0;
1366 }
1367
1368 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
1369 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1370 size_t last_transition = 0;
1371 size_t idx = 1;
1372 if (fchigh==0) fchigh=10;
1373 if (fclow==0) fclow=8;
1374 //set the threshold close to 0 (graph) or 128 std to avoid static
1375 size_t preLastSample = 0;
1376 size_t LastSample = 0;
1377 size_t currSample = 0;
1378 if ( size < 1024 ) return 0; // not enough samples
1379
1380 //find start of modulating data in trace
1381 idx = findModStart(dest, size, fchigh);
1382 // Need to threshold first sample
1383 if(dest[idx] < FSK_PSK_THRESHOLD) dest[0] = 0;
1384 else dest[0] = 1;
1385
1386 last_transition = idx;
1387 idx++;
1388 size_t numBits = 0;
1389 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
1390 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
1391 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
1392 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
1393 for(; idx < size; idx++) {
1394 // threshold current value
1395 if (dest[idx] < FSK_PSK_THRESHOLD) dest[idx] = 0;
1396 else dest[idx] = 1;
1397
1398 // Check for 0->1 transition
1399 if (dest[idx-1] < dest[idx]) {
1400 preLastSample = LastSample;
1401 LastSample = currSample;
1402 currSample = idx-last_transition;
1403 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
1404 //do nothing with extra garbage
1405 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
1406 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
1407 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
1408 dest[numBits-1]=1;
1409 }
1410 dest[numBits++]=1;
1411 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1412 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
1413 //do nothing with beginning garbage and reset.. should be rare..
1414 numBits = 0;
1415 } 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)
1416 dest[numBits++]=1;
1417 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1418 } else { //9+ = 10 sample waves (or 6+ = 7)
1419 dest[numBits++]=0;
1420 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
1421 }
1422 last_transition = idx;
1423 }
1424 }
1425 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
1426 }
1427
1428 //translate 11111100000 to 10
1429 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
1430 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1431 uint8_t lastval=dest[0];
1432 size_t idx=0;
1433 size_t numBits=0;
1434 uint32_t n=1;
1435 for( idx=1; idx < size; idx++) {
1436 n++;
1437 if (dest[idx]==lastval) continue; //skip until we hit a transition
1438
1439 //find out how many bits (n) we collected (use 1/2 clk tolerance)
1440 //if lastval was 1, we have a 1->0 crossing
1441 if (dest[idx-1]==1) {
1442 n = (n * fclow + rfLen/2) / rfLen;
1443 } else {// 0->1 crossing
1444 n = (n * fchigh + rfLen/2) / rfLen;
1445 }
1446 if (n == 0) n = 1;
1447
1448 //first transition - save startidx
1449 if (numBits == 0) {
1450 if (lastval == 1) { //high to low
1451 *startIdx += (fclow * idx) - (n*rfLen);
1452 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
1453 } else {
1454 *startIdx += (fchigh * idx) - (n*rfLen);
1455 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
1456 }
1457 }
1458
1459 //add to our destination the bits we collected
1460 memset(dest+numBits, dest[idx-1]^invert , n);
1461 numBits += n;
1462 n=0;
1463 lastval=dest[idx];
1464 }//end for
1465 // if valid extra bits at the end were all the same frequency - add them in
1466 if (n > rfLen/fchigh) {
1467 if (dest[idx-2]==1) {
1468 n = (n * fclow + rfLen/2) / rfLen;
1469 } else {
1470 n = (n * fchigh + rfLen/2) / rfLen;
1471 }
1472 memset(dest+numBits, dest[idx-1]^invert , n);
1473 numBits += n;
1474 }
1475 return numBits;
1476 }
1477
1478 //by marshmellow (from holiman's base)
1479 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
1480 int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1481 // FSK demodulator
1482 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
1483 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
1484 return size;
1485 }
1486
1487 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
1488 int startIdx=0;
1489 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
1490 }
1491
1492 // by marshmellow
1493 // convert psk1 demod to psk2 demod
1494 // only transition waves are 1s
1495 void psk1TOpsk2(uint8_t *BitStream, size_t size) {
1496 size_t i=1;
1497 uint8_t lastBit=BitStream[0];
1498 for (; i<size; i++){
1499 if (BitStream[i]==7){
1500 //ignore errors
1501 } else if (lastBit!=BitStream[i]){
1502 lastBit=BitStream[i];
1503 BitStream[i]=1;
1504 } else {
1505 BitStream[i]=0;
1506 }
1507 }
1508 return;
1509 }
1510
1511 // by marshmellow
1512 // convert psk2 demod to psk1 demod
1513 // from only transition waves are 1s to phase shifts change bit
1514 void psk2TOpsk1(uint8_t *BitStream, size_t size) {
1515 uint8_t phase=0;
1516 for (size_t i=0; i<size; i++){
1517 if (BitStream[i]==1){
1518 phase ^=1;
1519 }
1520 BitStream[i]=phase;
1521 }
1522 return;
1523 }
1524
1525 size_t pskFindFirstPhaseShift(uint8_t samples[], size_t size, uint8_t *curPhase, size_t waveStart, uint16_t fc, uint16_t *fullWaveLen) {
1526 uint16_t loopCnt = (size+3 < 4096) ? size : 4096; //don't need to loop through entire array...
1527
1528 uint16_t avgWaveVal=0, lastAvgWaveVal=0;
1529 size_t i = waveStart, waveEnd, waveLenCnt, firstFullWave;
1530 for (; i<loopCnt; i++) {
1531 // find peak
1532 if (samples[i]+fc < samples[i+1] && samples[i+1] >= samples[i+2]){
1533 waveEnd = i+1;
1534 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u", waveEnd, waveStart);
1535 waveLenCnt = waveEnd-waveStart;
1536 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+8)){ //not first peak and is a large wave but not out of whack
1537 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1538 firstFullWave = waveStart;
1539 *fullWaveLen = waveLenCnt;
1540 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1541 if (lastAvgWaveVal > FSK_PSK_THRESHOLD) *curPhase ^= 1;
1542 return firstFullWave;
1543 }
1544 waveStart = i+1;
1545 avgWaveVal = 0;
1546 }
1547 avgWaveVal += samples[i+2];
1548 }
1549 return 0;
1550 }
1551
1552 //by marshmellow - demodulate PSK1 wave
1553 //uses wave lengths (# Samples)
1554 int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1555 if (*size < 170) return -1;
1556
1557 uint8_t curPhase = *invert;
1558 size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1559 uint16_t fc=0, fullWaveLen=0, waveLenCnt=0, avgWaveVal, tol=1;
1560 uint16_t errCnt=0, errCnt2=0;
1561
1562 fc = countFC(dest, *size, 1);
1563 if ((fc >> 8) == 10) return -1; //fsk found - quit
1564 fc = fc & 0xFF;
1565 if (fc!=2 && fc!=4 && fc!=8) return -1;
1566 *clock = DetectPSKClock(dest, *size, *clock);
1567 if (*clock == 0) return -1;
1568
1569 //find start of modulating data in trace
1570 i = findModStart(dest, *size, fc);
1571
1572 //find first phase shift
1573 firstFullWave = pskFindFirstPhaseShift(dest, *size, &curPhase, i, fc, &fullWaveLen);
1574 if (firstFullWave == 0) {
1575 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1576 // so skip a little to ensure we are past any Start Signal
1577 firstFullWave = 160;
1578 memset(dest, curPhase, firstFullWave / *clock);
1579 } else {
1580 memset(dest, curPhase^1, firstFullWave / *clock);
1581 }
1582 //advance bits
1583 numBits += (firstFullWave / *clock);
1584 *startIdx = firstFullWave - (*clock * numBits)+2;
1585 //set start of wave as clock align
1586 lastClkBit = firstFullWave;
1587 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1588 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1589 waveStart = 0;
1590 dest[numBits++] = curPhase; //set first read bit
1591 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1592 //top edge of wave = start of new wave
1593 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1594 if (waveStart == 0) {
1595 waveStart = i+1;
1596 waveLenCnt = 0;
1597 avgWaveVal = dest[i+1];
1598 } else { //waveEnd
1599 waveEnd = i+1;
1600 waveLenCnt = waveEnd-waveStart;
1601 if (waveLenCnt > fc){
1602 //this wave is a phase shift
1603 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1604 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1605 curPhase ^= 1;
1606 dest[numBits++] = curPhase;
1607 lastClkBit += *clock;
1608 } else if (i < lastClkBit+10+fc){
1609 //noise after a phase shift - ignore
1610 } else { //phase shift before supposed to based on clock
1611 errCnt++;
1612 dest[numBits++] = 7;
1613 }
1614 } else if (i+1 > lastClkBit + *clock + tol + fc){
1615 lastClkBit += *clock; //no phase shift but clock bit
1616 dest[numBits++] = curPhase;
1617 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1618 errCnt2++;
1619 if(errCnt2 > 101) return errCnt2;
1620 }
1621 avgWaveVal = 0;
1622 waveStart = i+1;
1623 }
1624 }
1625 avgWaveVal += dest[i+1];
1626 }
1627 *size = numBits;
1628 return errCnt;
1629 }
1630
1631 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1632 int startIdx = 0;
1633 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
1634 }
1635
1636 //**********************************************************************************************
1637 //-----------------Tag format detection section-------------------------------------------------
1638 //**********************************************************************************************
1639
1640 // by marshmellow
1641 // FSK Demod then try to locate an AWID ID
1642 int AWIDdemodFSK(uint8_t *dest, size_t *size) {
1643 //make sure buffer has enough data
1644 if (*size < 96*50) return -1;
1645
1646 if (justNoise(dest, *size)) return -2;
1647
1648 // FSK demodulator
1649 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1650 if (*size < 96) return -3; //did we get a good demod?
1651
1652 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
1653 size_t startIdx = 0;
1654 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1655 if (errChk == 0) return -4; //preamble not found
1656 if (*size != 96) return -5;
1657 return (int)startIdx;
1658 }
1659
1660 //by marshmellow
1661 //takes 1s and 0s and searches for EM410x format - output EM ID
1662 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
1663 {
1664 //sanity checks
1665 if (*size < 64) return 0;
1666 if (BitStream[1]>1) return 0; //allow only 1s and 0s
1667
1668 // 111111111 bit pattern represent start of frame
1669 // include 0 in front to help get start pos
1670 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
1671 uint8_t errChk = 0;
1672 uint8_t FmtLen = 10; // sets of 4 bits = end data
1673 *startIdx = 0;
1674 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
1675 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
1676 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
1677
1678 //skip last 4bit parity row for simplicity
1679 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
1680 if (*size == 40) { // std em410x format
1681 *hi = 0;
1682 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
1683 } else if (*size == 88) { // long em format
1684 *hi = (bytebits_to_byte(BitStream, 24));
1685 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
1686 } else {
1687 return 0;
1688 }
1689 return 1;
1690 }
1691
1692 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
1693 // BitStream must contain previously askrawdemod and biphasedemoded data
1694 int FDXBdemodBI(uint8_t *dest, size_t *size) {
1695 //make sure buffer has enough data
1696 if (*size < 128) return -1;
1697
1698 size_t startIdx = 0;
1699 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
1700
1701 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1702 if (errChk == 0) return -2; //preamble not found
1703 return (int)startIdx;
1704 }
1705
1706 // by marshmellow
1707 // demod gProxIIDemod
1708 // error returns as -x
1709 // success returns start position in BitStream
1710 // BitStream must contain previously askrawdemod and biphasedemoded data
1711 int gProxII_Demod(uint8_t BitStream[], size_t *size) {
1712 size_t startIdx=0;
1713 uint8_t preamble[] = {1,1,1,1,1,0};
1714
1715 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
1716 if (errChk == 0) return -3; //preamble not found
1717 if (*size != 96) return -2; //should have found 96 bits
1718 //check first 6 spacer bits to verify format
1719 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
1720 //confirmed proper separator bits found
1721 //return start position
1722 return (int) startIdx;
1723 }
1724 return -5; //spacer bits not found - not a valid gproxII
1725 }
1726
1727 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
1728 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1729 if (justNoise(dest, *size)) return -1;
1730
1731 size_t numStart=0, size2=*size, startIdx=0;
1732 // FSK demodulator
1733 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1734 if (*size < 96*2) return -2;
1735 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1736 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
1737 // find bitstring in array
1738 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1739 if (errChk == 0) return -3; //preamble not found
1740
1741 numStart = startIdx + sizeof(preamble);
1742 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1743 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1744 if (dest[idx] == dest[idx+1]){
1745 return -4; //not manchester data
1746 }
1747 *hi2 = (*hi2<<1)|(*hi>>31);
1748 *hi = (*hi<<1)|(*lo>>31);
1749 //Then, shift in a 0 or one into low
1750 if (dest[idx] && !dest[idx+1]) // 1 0
1751 *lo=(*lo<<1)|1;
1752 else // 0 1
1753 *lo=(*lo<<1)|0;
1754 }
1755 return (int)startIdx;
1756 }
1757
1758 int IOdemodFSK(uint8_t *dest, size_t size) {
1759 if (justNoise(dest, size)) return -1;
1760 //make sure buffer has data
1761 if (size < 66*64) return -2;
1762 // FSK demodulator
1763 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
1764 if (size < 65) return -3; //did we get a good demod?
1765 //Index map
1766 //0 10 20 30 40 50 60
1767 //| | | | | | |
1768 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
1769 //-----------------------------------------------------------------------------
1770 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
1771 //
1772 //XSF(version)facility:codeone+codetwo
1773 //Handle the data
1774 size_t startIdx = 0;
1775 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
1776 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
1777 if (errChk == 0) return -4; //preamble not found
1778
1779 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
1780 //confirmed proper separator bits found
1781 //return start position
1782 return (int) startIdx;
1783 }
1784 return -5;
1785 }
1786
1787 // redesigned by marshmellow adjusted from existing decode functions
1788 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1789 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1790 //26 bit 40134 format (don't know other formats)
1791 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};
1792 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};
1793 size_t startidx = 0;
1794 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1795 // if didn't find preamble try again inverting
1796 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1797 *invert ^= 1;
1798 }
1799 if (*size != 64 && *size != 224) return -2;
1800 if (*invert==1)
1801 for (size_t i = startidx; i < *size; i++)
1802 bitStream[i] ^= 1;
1803
1804 return (int) startidx;
1805 }
1806
1807 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
1808 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1809 if (justNoise(dest, *size)) return -1;
1810
1811 size_t numStart=0, size2=*size, startIdx=0;
1812 // FSK demodulator
1813 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1814 if (*size < 96) return -2;
1815
1816 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1817 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
1818
1819 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1820 if (errChk == 0) return -3; //preamble not found
1821
1822 numStart = startIdx + sizeof(preamble);
1823 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1824 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1825 if (dest[idx] == dest[idx+1])
1826 return -4; //not manchester data
1827 *hi2 = (*hi2<<1)|(*hi>>31);
1828 *hi = (*hi<<1)|(*lo>>31);
1829 //Then, shift in a 0 or one into low
1830 if (dest[idx] && !dest[idx+1]) // 1 0
1831 *lo=(*lo<<1)|1;
1832 else // 0 1
1833 *lo=(*lo<<1)|0;
1834 }
1835 return (int)startIdx;
1836 }
1837
1838 // find presco preamble 0x10D in already demoded data
1839 int PrescoDemod(uint8_t *dest, size_t *size) {
1840 //make sure buffer has data
1841 if (*size < 64*2) return -2;
1842
1843 size_t startIdx = 0;
1844 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
1845 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1846 if (errChk == 0) return -4; //preamble not found
1847 //return start position
1848 return (int) startIdx;
1849 }
1850
1851 // by marshmellow
1852 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
1853 int PyramiddemodFSK(uint8_t *dest, size_t *size) {
1854 //make sure buffer has data
1855 if (*size < 128*50) return -5;
1856
1857 //test samples are not just noise
1858 if (justNoise(dest, *size)) return -1;
1859
1860 // FSK demodulator
1861 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1862 if (*size < 128) return -2; //did we get a good demod?
1863
1864 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
1865 size_t startIdx = 0;
1866 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1867 if (errChk == 0) return -4; //preamble not found
1868 if (*size != 128) return -3;
1869 return (int)startIdx;
1870 }
1871
1872 // by marshmellow
1873 // find viking preamble 0xF200 in already demoded data
1874 int VikingDemod_AM(uint8_t *dest, size_t *size) {
1875 //make sure buffer has data
1876 if (*size < 64*2) return -2;
1877
1878 size_t startIdx = 0;
1879 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};
1880 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1881 if (errChk == 0) return -4; //preamble not found
1882 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
1883 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
1884 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
1885 if ( checkCalc != 0xA8 ) return -5;
1886 if (*size != 64) return -6;
1887 //return start position
1888 return (int) startIdx;
1889 }
1890
1891 // by iceman
1892 // find Visa2000 preamble in already demoded data
1893 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1894 if (*size < 96) return -1; //make sure buffer has data
1895 size_t startIdx = 0;
1896 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};
1897 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1898 return -2; //preamble not found
1899 if (*size != 96) return -3; //wrong demoded size
1900 //return start position
1901 return (int)startIdx;
1902 }
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