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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
9 //-----------------------------------------------------------------------------
10 #include "lfdemod.h"
11
12 //un_comment to allow debug print calls when used not on device
13 void dummy(char *fmt, ...){}
14 void dummy_sgc (int clock, int startidx) {}
15
16 #ifndef ON_DEVICE
17 # include "ui.h" // plotclock, plotclockstartindex
18 # include "cmdparser.h"
19 # include "cmddata.h"
20 # define prnt PrintAndLog
21 # define sgc SetGraphClock
22 void SetGraphClock(int clock, int startidx){
23 PlotClock = clock;
24 PlockClockStartIndex = startidx;
25 }
26 #else
27 uint8_t g_debugMode = 0;
28 # define prnt dummy
29 # define sgc dummy_sgc
30 #endif
31
32 //test samples are not just noise
33 uint8_t justNoise(uint8_t *bits, size_t size) {
34 #define THRESHOLD 123
35 uint8_t val = 1;
36 for(size_t idx = 0; idx < size && val; idx++)
37 val = bits[idx] < THRESHOLD;
38 return val;
39 }
40
41 //by marshmellow
42 //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
43 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
44 {
45 *high=0;
46 *low=255;
47 // get high and low thresholds
48 for (size_t i=0; i < size; i++){
49 if (BitStream[i] > *high) *high = BitStream[i];
50 if (BitStream[i] < *low) *low = BitStream[i];
51 }
52 if (*high < 123) return -1; // just noise
53 *high = ((*high-128)*fuzzHi + 12800)/100;
54 *low = ((*low-128)*fuzzLo + 12800)/100;
55 return 1;
56 }
57
58 // by marshmellow
59 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
60 // returns 1 if passed
61 uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
62 {
63 uint8_t ans = 0;
64 for (uint8_t i = 0; i < bitLen; i++){
65 ans ^= ((bits >> i) & 1);
66 }
67 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
68 return (ans == pType);
69 }
70
71 //by marshmellow
72 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
73 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
74 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
75 {
76 uint32_t parityWd = 0;
77 size_t j = 0, bitCnt = 0;
78 for (int word = 0; word < (bLen); word += pLen){
79 for (int bit=0; bit < pLen; bit++){
80 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
81 BitStream[j++] = (BitStream[startIdx+word+bit]);
82 }
83 if (word+pLen > bLen) break;
84
85 j--; // overwrite parity with next data
86 // if parity fails then return 0
87 switch (pType) {
88 case 3: if (BitStream[j]==1) { return 0; } break; //should be 0 spacer bit
89 case 2: if (BitStream[j]==0) { return 0; } break; //should be 1 spacer bit
90 default: if (parityTest(parityWd, pLen, pType) == 0) { return 0; } break; //test parity
91 }
92 bitCnt += (pLen-1);
93 parityWd = 0;
94 }
95 // if we got here then all the parities passed
96 //return ID start index and size
97 return bitCnt;
98 }
99
100 // by marshmellow
101 // takes a array of binary values, length of bits per parity (includes parity bit),
102 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
103 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
104 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
105 {
106 uint32_t parityWd = 0;
107 size_t j = 0, bitCnt = 0;
108 for (int word = 0; word < sourceLen; word+=pLen-1) {
109 for (int bit=0; bit < pLen-1; bit++){
110 parityWd = (parityWd << 1) | BitSource[word+bit];
111 dest[j++] = (BitSource[word+bit]);
112 }
113
114 // if parity fails then return 0
115 switch (pType) {
116 case 3: dest[j++]=0; break; // marker bit which should be a 0
117 case 2: dest[j++]=1; break; // marker bit which should be a 1
118 default:
119 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
120 break;
121 }
122 bitCnt += pLen;
123 parityWd = 0;
124 }
125 // if we got here then all the parities passed
126 //return ID start index and size
127 return bitCnt;
128 }
129
130 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
131 {
132 uint32_t num = 0;
133 for(int i = 0 ; i < numbits ; i++) {
134 num = (num << 1) | (*src);
135 src++;
136 }
137 return num;
138 }
139
140 //least significant bit first
141 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
142 {
143 uint32_t num = 0;
144 for(int i = 0 ; i < numbits ; i++) {
145 num = (num << 1) | *(src + (numbits-(i+1)));
146 }
147 return num;
148 }
149
150 //by marshmellow
151 // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
152 bool preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx){
153 return preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false);
154 }
155 //by marshmellow
156 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
157 // param @findone: look for a repeating preamble or only the first.
158 // em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
159 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone)
160 {
161 // Sanity check. If preamble length is bigger than bitstream length.
162 if ( *size <= pLen ) return false;
163
164 uint8_t foundCnt = 0;
165 for (int idx = 0; idx < *size - pLen; idx++){
166 if (memcmp(BitStream+idx, preamble, pLen) == 0){
167 if (g_debugMode) prnt("DEBUG: preamble found at %i", idx);
168 //first index found
169 foundCnt++;
170 if (foundCnt == 1){
171 *startIdx = idx;
172 if (findone) return true;
173 }
174 if (foundCnt == 2){
175 *size = idx - *startIdx;
176 return true;
177 }
178 }
179 }
180 return false;
181 }
182
183 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
184 size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
185 size_t i = 0;
186 size_t waveSizeCnt = 0;
187 uint8_t thresholdCnt = 0;
188 bool isAboveThreshold = dest[i++] >= threshold_value;
189 for (; i < size-20; i++ ) {
190 if(dest[i] < threshold_value && isAboveThreshold) {
191 thresholdCnt++;
192 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
193 isAboveThreshold = false;
194 waveSizeCnt = 0;
195 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
196 thresholdCnt++;
197 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
198 isAboveThreshold = true;
199 waveSizeCnt = 0;
200 } else {
201 waveSizeCnt++;
202 }
203 if (thresholdCnt > 10) break;
204 }
205 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
206 return i;
207 }
208
209 //by marshmellow
210 //takes 1s and 0s and searches for EM410x format - output EM ID
211 // actually, no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
212 int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
213 {
214 // sanity check
215 if (*size < 64) return -3;
216 if (BitStream[1] > 1) return -1;
217
218 uint8_t fmtlen;
219 *startIdx = 0;
220
221 // preamble 0111111111
222 // include 0 in front to help get start pos
223 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
224 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
225 return -2;
226
227 //XL and normal size.
228 if (*size != 64 && *size != 128) return -3;
229
230 fmtlen = (*size == 128) ? 22 : 10;
231
232 //skip last 4bit parity row for simplicity
233 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);
234
235 switch (*size) {
236 case 40: {
237 // std em410x format
238 *hi = 0;
239 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
240 break;
241 }
242 case 88: {
243 // long em format
244 *hi = (bytebits_to_byte(BitStream, 24));
245 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
246 break;
247 }
248 default: return -4;
249 }
250 return 1;
251 }
252
253 //by marshmellow
254 //demodulates strong heavily clipped samples
255 //RETURN: num of errors. if 0, is ok.
256 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
257 {
258 size_t bitCnt=0, smplCnt=0, errCnt=0;
259 uint8_t waveHigh = 0;
260 for (size_t i=0; i < *size; i++){
261 if (BinStream[i] >= high && waveHigh){
262 smplCnt++;
263 } else if (BinStream[i] <= low && !waveHigh){
264 smplCnt++;
265 } else { //transition
266 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
267
268 if (smplCnt > clk-(clk/4)-1) { //full clock
269 if (smplCnt > clk + (clk/4)+1) { //too many samples
270 errCnt++;
271 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
272 BinStream[bitCnt++] = 7;
273 } else if (waveHigh) {
274 BinStream[bitCnt++] = invert;
275 BinStream[bitCnt++] = invert;
276 } else if (!waveHigh) {
277 BinStream[bitCnt++] = invert ^ 1;
278 BinStream[bitCnt++] = invert ^ 1;
279 }
280 waveHigh ^= 1;
281 smplCnt = 0;
282 } else if (smplCnt > (clk/2) - (clk/4)-1) {
283 if (waveHigh) {
284 BinStream[bitCnt++] = invert;
285 } else if (!waveHigh) {
286 BinStream[bitCnt++] = invert ^ 1;
287 }
288 waveHigh ^= 1;
289 smplCnt = 0;
290 } else if (!bitCnt) {
291 //first bit
292 waveHigh = (BinStream[i] >= high);
293 smplCnt = 1;
294 } else {
295 smplCnt++;
296 //transition bit oops
297 }
298 } else { //haven't hit new high or new low yet
299 smplCnt++;
300 }
301 }
302 }
303 *size = bitCnt;
304 return errCnt;
305 }
306
307 //by marshmellow
308 void askAmp(uint8_t *BitStream, size_t size)
309 {
310 uint8_t last = 128;
311 for(size_t i = 1; i < size; ++i){
312 if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
313 last = 255;
314 else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
315 last = 0;
316
317 BitStream[i] = last;
318 }
319 }
320
321 //by marshmellow
322 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
323 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
324 {
325 if (*size==0) return -1;
326 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
327 if (*clk==0 || start < 0) return -3;
328 if (*invert != 1) *invert = 0;
329 if (amp==1) askAmp(BinStream, *size);
330 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
331
332 sgc(*clk, start);
333
334 uint8_t initLoopMax = 255;
335 if (initLoopMax > *size) initLoopMax = *size;
336 // Detect high and lows
337 //25% clip in case highs and lows aren't clipped [marshmellow]
338 int high, low;
339 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
340 return -2; //just noise
341
342 size_t errCnt = 0;
343 // if clean clipped waves detected run alternate demod
344 if (DetectCleanAskWave(BinStream, *size, high, low)) {
345 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
346 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
347 if (askType) //askman
348 return manrawdecode(BinStream, size, 0);
349 //askraw
350 return errCnt;
351 }
352 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
353
354 int lastBit; //set first clock check - can go negative
355 size_t i, bitnum = 0; //output counter
356 uint8_t midBit = 0;
357 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
358 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
359 size_t MaxBits = 3072; //max bits to collect
360 lastBit = start - *clk;
361
362 for (i = start; i < *size; ++i) {
363 if (i-lastBit >= *clk-tol){
364 if (BinStream[i] >= high) {
365 BinStream[bitnum++] = *invert;
366 } else if (BinStream[i] <= low) {
367 BinStream[bitnum++] = *invert ^ 1;
368 } else if (i-lastBit >= *clk+tol) {
369 if (bitnum > 0) {
370 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
371 BinStream[bitnum++]=7;
372 errCnt++;
373 }
374 } else { //in tolerance - looking for peak
375 continue;
376 }
377 midBit = 0;
378 lastBit += *clk;
379 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
380 if (BinStream[i] >= high) {
381 BinStream[bitnum++] = *invert;
382 } else if (BinStream[i] <= low) {
383 BinStream[bitnum++] = *invert ^ 1;
384 } else if (i-lastBit >= *clk/2+tol) {
385 BinStream[bitnum] = BinStream[bitnum-1];
386 bitnum++;
387 } else { //in tolerance - looking for peak
388 continue;
389 }
390 midBit = 1;
391 }
392 if (bitnum >= MaxBits) break;
393 }
394 *size = bitnum;
395 return errCnt;
396 }
397 //by marshmellow
398 //take 10 and 01 and manchester decode
399 //run through 2 times and take least errCnt
400 int manrawdecode(uint8_t *BitStream, size_t *size, uint8_t invert){
401
402 // sanity check
403 if (*size < 16) return -1;
404
405 int errCnt = 0, bestErr = 1000;
406 uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;
407 size_t i, k;
408
409 //find correct start position [alignment]
410 for (k = 0; k < 2; ++k){
411 for (i = k; i < *size-3; i += 2) {
412 if (BitStream[i] == BitStream[i+1])
413 errCnt++;
414 }
415 if (bestErr > errCnt){
416 bestErr = errCnt;
417 bestRun = k;
418 }
419 errCnt = 0;
420 }
421
422 //decode
423 for (i = bestRun; i < *size-3; i += 2){
424 if (BitStream[i] == 1 && (BitStream[i+1] == 0)){
425 BitStream[bitnum++] = invert;
426 } else if ((BitStream[i] == 0) && BitStream[i+1] == 1){
427 BitStream[bitnum++] = invert^1;
428 } else {
429 BitStream[bitnum++] = 7;
430 }
431 if (bitnum > MaxBits) break;
432 }
433 *size = bitnum;
434 return bestErr;
435 }
436
437 uint32_t manchesterEncode2Bytes(uint16_t datain) {
438 uint32_t output = 0;
439 uint8_t curBit = 0;
440 for (uint8_t i=0; i<16; i++) {
441 curBit = (datain >> (15-i) & 1);
442 output |= (1<<(((15-i)*2)+curBit));
443 }
444 return output;
445 }
446
447 //by marshmellow
448 //encode binary data into binary manchester
449 int ManchesterEncode(uint8_t *BitStream, size_t size)
450 {
451 size_t modIdx=20000, i=0;
452 if (size>modIdx) return -1;
453 for (size_t idx=0; idx < size; idx++){
454 BitStream[idx+modIdx++] = BitStream[idx];
455 BitStream[idx+modIdx++] = BitStream[idx]^1;
456 }
457 for (; i<(size*2); i++){
458 BitStream[i] = BitStream[i+20000];
459 }
460 return i;
461 }
462
463 //by marshmellow
464 //take 01 or 10 = 1 and 11 or 00 = 0
465 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
466 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
467 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
468 {
469 uint16_t bitnum = 0;
470 uint16_t errCnt = 0;
471 size_t i = offset;
472 uint16_t MaxBits=512;
473 //if not enough samples - error
474 if (*size < 51) return -1;
475 //check for phase change faults - skip one sample if faulty
476 uint8_t offsetA = 1, offsetB = 1;
477 for (; i<48; i+=2){
478 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
479 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
480 }
481 if (!offsetA && offsetB) offset++;
482 for (i=offset; i<*size-3; i+=2){
483 //check for phase error
484 if (BitStream[i+1]==BitStream[i+2]) {
485 BitStream[bitnum++]=7;
486 errCnt++;
487 }
488 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
489 BitStream[bitnum++]=1^invert;
490 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
491 BitStream[bitnum++]=invert;
492 } else {
493 BitStream[bitnum++]=7;
494 errCnt++;
495 }
496 if(bitnum>MaxBits) break;
497 }
498 *size=bitnum;
499 return errCnt;
500 }
501
502 // by marshmellow
503 // demod gProxIIDemod
504 // error returns as -x
505 // success returns start position in BitStream
506 // BitStream must contain previously askrawdemod and biphasedemoded data
507 int gProxII_Demod(uint8_t BitStream[], size_t *size)
508 {
509 size_t startIdx=0;
510 uint8_t preamble[] = {1,1,1,1,1,0};
511
512 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx))
513 return -3; //preamble not found
514
515 if (*size != 96) return -2; //should have found 96 bits
516
517 //check first 6 spacer bits to verify format
518 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
519 //confirmed proper separator bits found
520 //return start position
521 return (int) startIdx;
522 }
523 return -5; //spacer bits not found - not a valid gproxII
524 }
525
526 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
527 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
528 {
529 size_t last_transition = 0;
530 size_t idx = 1;
531 if (fchigh==0) fchigh=10;
532 if (fclow==0) fclow=8;
533 //set the threshold close to 0 (graph) or 128 std to avoid static
534 uint8_t threshold_value = 123;
535 size_t preLastSample = 0;
536 size_t LastSample = 0;
537 size_t currSample = 0;
538 if ( size < 1024 ) return 0; // not enough samples
539
540 //find start of modulating data in trace
541 idx = findModStart(dest, size, threshold_value, fchigh);
542
543 // Need to threshold first sample
544 if(dest[idx] < threshold_value) dest[0] = 0;
545 else dest[0] = 1;
546 idx++;
547
548 size_t numBits = 0;
549 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
550 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
551 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
552 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
553 for(; idx < size-20; idx++) {
554 // threshold current value
555
556 if (dest[idx] < threshold_value) dest[idx] = 0;
557 else dest[idx] = 1;
558
559 // Check for 0->1 transition
560 if (dest[idx-1] < dest[idx]) {
561 preLastSample = LastSample;
562 LastSample = currSample;
563 currSample = idx-last_transition;
564 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
565 //do nothing with extra garbage
566 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
567 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
568 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
569 dest[numBits-1]=1;
570 }
571 dest[numBits++]=1;
572
573 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
574 //do nothing with beginning garbage and reset.. should be rare..
575 numBits = 0;
576 } 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)
577 dest[numBits++]=1;
578 } else { //9+ = 10 sample waves (or 6+ = 7)
579 dest[numBits++]=0;
580 }
581 last_transition = idx;
582 }
583 }
584 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
585 }
586
587 //translate 11111100000 to 10
588 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
589 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
590 uint8_t invert, uint8_t fchigh, uint8_t fclow)
591 {
592 uint8_t lastval=dest[0];
593 size_t idx=0;
594 size_t numBits=0;
595 uint32_t n=1;
596 for( idx=1; idx < size; idx++) {
597 n++;
598 if (dest[idx]==lastval) continue; //skip until we hit a transition
599
600 //find out how many bits (n) we collected
601 //if lastval was 1, we have a 1->0 crossing
602 if (dest[idx-1]==1) {
603 n = (n * fclow + rfLen/2) / rfLen;
604 } else {// 0->1 crossing
605 n = (n * fchigh + rfLen/2) / rfLen;
606 }
607 if (n == 0) n = 1;
608
609 //add to our destination the bits we collected
610 memset(dest+numBits, dest[idx-1]^invert , n);
611 numBits += n;
612 n=0;
613 lastval=dest[idx];
614 }//end for
615 // if valid extra bits at the end were all the same frequency - add them in
616 if (n > rfLen/fchigh) {
617 if (dest[idx-2]==1) {
618 n = (n * fclow + rfLen/2) / rfLen;
619 } else {
620 n = (n * fchigh + rfLen/2) / rfLen;
621 }
622 memset(dest+numBits, dest[idx-1]^invert , n);
623 numBits += n;
624 }
625 return numBits;
626 }
627
628 //by marshmellow (from holiman's base)
629 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
630 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
631 {
632 // FSK demodulator
633 size = fsk_wave_demod(dest, size, fchigh, fclow);
634 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
635 return size;
636 }
637
638 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
639 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
640 {
641 if (justNoise(dest, *size)) return -1;
642
643 size_t numStart=0, size2 = *size, startIdx=0;
644 // FSK demodulator
645 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
646 if (*size < 96*2) return -2;
647 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
648 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
649 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
650 return -3; //preamble not found
651
652 numStart = startIdx + sizeof(preamble);
653 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
654 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
655 if (dest[idx] == dest[idx+1]){
656 return -4; //not manchester data
657 }
658 *hi2 = (*hi2<<1)|(*hi>>31);
659 *hi = (*hi<<1)|(*lo>>31);
660 //Then, shift in a 0 or one into low
661 *lo <<= 1;
662 if (dest[idx] && !dest[idx+1]) // 1 0
663 *lo |= 1;
664 else // 0 1
665 *lo |= 0;
666 }
667 return (int)startIdx;
668 }
669
670 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
671 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
672 {
673 if (justNoise(dest, *size)) return -1;
674
675 size_t numStart=0, size2 = *size, startIdx=0;
676 // FSK demodulator
677 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
678 if (*size < 96) return -2;
679
680 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
681 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
682 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
683 return -3; //preamble not found
684
685 numStart = startIdx + sizeof(preamble);
686 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
687 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
688 if (dest[idx] == dest[idx+1])
689 return -4; //not manchester data
690 *hi2 = (*hi2<<1)|(*hi>>31);
691 *hi = (*hi<<1)|(*lo>>31);
692 //Then, shift in a 0 or one into low
693 if (dest[idx] && !dest[idx+1]) // 1 0
694 *lo=(*lo<<1)|1;
695 else // 0 1
696 *lo=(*lo<<1)|0;
697 }
698 return (int)startIdx;
699 }
700
701 int IOdemodFSK(uint8_t *dest, size_t size)
702 {
703 if (justNoise(dest, size)) return -1;
704 //make sure buffer has data
705 if (size < 66*64) return -2;
706 // FSK demodulator
707 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
708 if (size < 65) return -3; //did we get a good demod?
709 //Index map
710 //0 10 20 30 40 50 60
711 //| | | | | | |
712 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
713 //-----------------------------------------------------------------------------
714 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
715 //
716 //XSF(version)facility:codeone+codetwo
717 //Handle the data
718 size_t startIdx = 0;
719 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
720 if (! preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx))
721 return -4; //preamble not found
722
723 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
724 //confirmed proper separator bits found
725 //return start position
726 return (int) startIdx;
727 }
728 return -5;
729 }
730
731 // by marshmellow
732 // find viking preamble 0xF200 in already demoded data
733 int VikingDemod_AM(uint8_t *dest, size_t *size) {
734 //make sure buffer has data
735 if (*size < 64*2) return -2;
736 size_t startIdx = 0;
737 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};
738 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
739 return -4; //preamble not found
740
741 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^
742 bytebits_to_byte(dest+startIdx+8,8) ^
743 bytebits_to_byte(dest+startIdx+16,8) ^
744 bytebits_to_byte(dest+startIdx+24,8) ^
745 bytebits_to_byte(dest+startIdx+32,8) ^
746 bytebits_to_byte(dest+startIdx+40,8) ^
747 bytebits_to_byte(dest+startIdx+48,8) ^
748 bytebits_to_byte(dest+startIdx+56,8);
749 if ( checkCalc != 0xA8 ) return -5;
750 if (*size != 64) return -6;
751 //return start position
752 return (int)startIdx;
753 }
754
755 // by iceman
756 // find Visa2000 preamble in already demoded data
757 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
758 if (*size < 96) return -1; //make sure buffer has data
759 size_t startIdx = 0;
760 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};
761 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
762 return -2; //preamble not found
763 if (*size != 96) return -3; //wrong demoded size
764 //return start position
765 return (int)startIdx;
766 }
767 // by iceman
768 // find Noralsy preamble in already demoded data
769 int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
770 if (*size < 96) return -1; //make sure buffer has data
771 size_t startIdx = 0;
772 uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};
773 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
774 return -2; //preamble not found
775 if (*size != 96) return -3; //wrong demoded size
776 //return start position
777 return (int)startIdx;
778 }
779 // find presco preamble 0x10D in already demoded data
780 int PrescoDemod(uint8_t *dest, size_t *size) {
781 if (*size < 128*2) return -1; //make sure buffer has data
782 size_t startIdx = 0;
783 uint8_t preamble[] = {0,0,0,1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
784 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
785 return -2; //preamble not found
786 if (*size != 128) return -3; //wrong demoded size
787 //return start position
788 return (int)startIdx;
789 }
790
791 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
792 // BitStream must contain previously askrawdemod and biphasedemoded data
793 int FDXBdemodBI(uint8_t *dest, size_t *size) {
794 if (*size < 128*2) return -1; //make sure buffer has enough data
795 size_t startIdx = 0;
796 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
797 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
798 return -2; //preamble not found
799 if (*size != 128) return -3; //wrong demoded size
800 //return start position
801 return (int)startIdx;
802 }
803
804 // ASK/Diphase fc/64 (inverted Biphase)
805 // Note: this i s not a demod, this is only a detection
806 // the parameter *dest needs to be demoded before call
807 // 0xFFFF preamble, 64bits
808 int JablotronDemod(uint8_t *dest, size_t *size){
809 if (*size < 64*2) return -1; //make sure buffer has enough data
810 size_t startIdx = 0;
811 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
812 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
813 return -2; //preamble not found
814 if (*size != 64) return -3; // wrong demoded size
815
816 uint8_t checkchksum = 0;
817 for (int i=16; i < 56; i += 8) {
818 checkchksum += bytebits_to_byte(dest+startIdx+i,8);
819 }
820 checkchksum ^= 0x3A;
821 uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
822 if ( checkchksum != crc ) return -5;
823 return (int)startIdx;
824 }
825
826 // by marshmellow
827 // FSK Demod then try to locate an AWID ID
828 int AWIDdemodFSK(uint8_t *dest, size_t *size)
829 {
830 //make sure buffer has enough data
831 if (*size < 96*50) return -1;
832
833 if (justNoise(dest, *size)) return -2;
834
835 // FSK demodulator
836 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
837 if (*size < 96) return -3; //did we get a good demod?
838
839 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
840 size_t startIdx = 0;
841 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
842 return -4; //preamble not found
843 if (*size != 96) return -5;
844 return (int)startIdx;
845 }
846
847 // by marshmellow
848 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
849 int PyramiddemodFSK(uint8_t *dest, size_t *size)
850 {
851 //make sure buffer has data
852 if (*size < 128*50) return -5;
853
854 //test samples are not just noise
855 if (justNoise(dest, *size)) return -1;
856
857 // FSK demodulator
858 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
859 if (*size < 128) return -2; //did we get a good demod?
860 size_t startIdx = 0;
861 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1};
862 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
863 return -4; //preamble not found
864 if (*size != 128) return -3;
865 return (int)startIdx;
866 }
867
868 // find nedap preamble in already demoded data
869 int NedapDemod(uint8_t *dest, size_t *size) {
870 //make sure buffer has data
871 if (*size < 128) return -3;
872
873 size_t startIdx = 0;
874 //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
875 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
876 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
877 return -4; //preamble not found
878 return (int) startIdx;
879 }
880
881 // Find IDTEC PSK1, RF Preamble == 0x4944544B, Demodsize 64bits
882 // by iceman
883 int IdteckDemodPSK(uint8_t *dest, size_t *size) {
884 //make sure buffer has data
885 if (*size < 64*2) return -1;
886 size_t startIdx = 0;
887 uint8_t preamble[] = {0,1,0,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,1,0,1,1};
888 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
889 return -2; //preamble not found
890 if (*size != 64) return -3; // wrong demoded size
891 return (int) startIdx;
892 }
893
894 // by marshmellow
895 // to detect a wave that has heavily clipped (clean) samples
896 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
897 {
898 bool allArePeaks = true;
899 uint16_t cntPeaks=0;
900 size_t loopEnd = 512+160;
901 if (loopEnd > size) loopEnd = size;
902 for (size_t i=160; i<loopEnd; i++){
903 if (dest[i]>low && dest[i]<high)
904 allArePeaks = false;
905 else
906 cntPeaks++;
907 }
908 if (!allArePeaks){
909 if (cntPeaks > 300) return true;
910 }
911 return allArePeaks;
912 }
913 // by marshmellow
914 // to help detect clocks on heavily clipped samples
915 // based on count of low to low
916 int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock)
917 {
918 uint8_t clocks[] = {8,16,32,40,50,64,128};
919 size_t startwave;
920 size_t i = 100;
921 size_t minClk = 255;
922 int shortestWaveIdx = 0;
923 // get to first full low to prime loop and skip incomplete first pulse
924 while ((dest[i] < high) && (i < size))
925 ++i;
926 while ((dest[i] > low) && (i < size))
927 ++i;
928
929 // loop through all samples
930 while (i < size) {
931 // measure from low to low
932 while ((dest[i] > low) && (i < size))
933 ++i;
934 startwave= i;
935 while ((dest[i] < high) && (i < size))
936 ++i;
937 while ((dest[i] > low) && (i < size))
938 ++i;
939 //get minimum measured distance
940 if (i-startwave < minClk && i < size) {
941 minClk = i - startwave;
942 shortestWaveIdx = startwave;
943 }
944 }
945 // set clock
946 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
947 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
948 if (minClk >= clocks[clkCnt]-(clocks[clkCnt]/8) && minClk <= clocks[clkCnt]+1)
949 *clock = clocks[clkCnt];
950 return shortestWaveIdx;
951 }
952 return 0;
953 }
954
955 // by marshmellow
956 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
957 // maybe somehow adjust peak trimming value based on samples to fix?
958 // return start index of best starting position for that clock and return clock (by reference)
959 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
960 {
961 size_t i = 1;
962 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
963 uint8_t clkEnd = 9;
964 uint8_t loopCnt = 255; //don't need to loop through entire array...
965 if (size <= loopCnt + 60) return -1; //not enough samples
966 size -= 60; //sometimes there is a strange end wave - filter out this....
967 //if we already have a valid clock
968 uint8_t clockFnd = 0;
969 for (; i < clkEnd; ++i)
970 if (clk[i] == *clock) clockFnd = i;
971 //clock found but continue to find best startpos
972
973 //get high and low peak
974 int peak, low;
975 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
976
977 //test for large clean peaks
978 if (!clockFnd){
979 if (DetectCleanAskWave(dest, size, peak, low)==1){
980 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
981 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i", clock ,ans);
982 if (ans > 0){
983 return ans; // return shortest wave start pos
984 }
985 }
986 }
987 uint8_t ii;
988 uint8_t clkCnt, tol = 0;
989 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
990 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
991 size_t errCnt = 0;
992 size_t arrLoc, loopEnd;
993
994 if (clockFnd > 0) {
995 clkCnt = clockFnd;
996 clkEnd = clockFnd+1;
997 } else {
998 clkCnt = 1;
999 }
1000
1001 //test each valid clock from smallest to greatest to see which lines up
1002 for (; clkCnt < clkEnd; clkCnt++) {
1003 if (clk[clkCnt] <= 32) {
1004 tol=1;
1005 } else {
1006 tol=0;
1007 }
1008 //if no errors allowed - keep start within the first clock
1009 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128)
1010 loopCnt = clk[clkCnt] * 2;
1011
1012 bestErr[clkCnt] = 1000;
1013
1014 //try lining up the peaks by moving starting point (try first few clocks)
1015 for (ii=0; ii < loopCnt; ii++){
1016 if (dest[ii] < peak && dest[ii] > low) continue;
1017
1018 errCnt = 0;
1019 // now that we have the first one lined up test rest of wave array
1020 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
1021 for (i=0; i < loopEnd; ++i){
1022 arrLoc = ii + (i * clk[clkCnt]);
1023 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
1024 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
1025 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
1026 }else{ //error no peak detected
1027 errCnt++;
1028 }
1029 }
1030 //if we found no errors then we can stop here and a low clock (common clocks)
1031 // this is correct one - return this clock
1032 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
1033 if (errCnt==0 && clkCnt<7) {
1034 if (!clockFnd) *clock = clk[clkCnt];
1035 return ii;
1036 }
1037 //if we found errors see if it is lowest so far and save it as best run
1038 if (errCnt < bestErr[clkCnt]) {
1039 bestErr[clkCnt] = errCnt;
1040 bestStart[clkCnt] = ii;
1041 }
1042 }
1043 }
1044 uint8_t k;
1045 uint8_t best = 0;
1046 for (k=1; k < clkEnd; ++k){
1047 if (bestErr[k] < bestErr[best]){
1048 if (bestErr[k] == 0) bestErr[k]=1;
1049 // current best bit to error ratio vs new bit to error ratio
1050 if ( (size/clk[best])/bestErr[best] < (size/clk[k])/bestErr[k] ){
1051 best = k;
1052 }
1053 }
1054 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d", clk[k], bestErr[k], clk[best], bestStart[best]);
1055 }
1056 if (!clockFnd) *clock = clk[best];
1057
1058 return bestStart[best];
1059 }
1060
1061 int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
1062 int firstPhaseShift = 0;
1063 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
1064 }
1065
1066 //by marshmellow
1067 //detect psk clock by reading each phase shift
1068 // a phase shift is determined by measuring the sample length of each wave
1069 int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
1070 uint8_t clk[] = {255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
1071 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1072
1073 //if we already have a valid clock quit
1074 size_t i=1;
1075 for (; i < 8; ++i)
1076 if (clk[i] == clock) return clock;
1077
1078 if (size < 160+20) return 0;
1079 // size must be larger than 20 here, and 160 later on.
1080 if (size < loopCnt) loopCnt = size-20;
1081
1082 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
1083 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
1084 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
1085 uint16_t bestErr[] = {1000,1000,1000,1000,1000,1000,1000,1000,1000};
1086 uint16_t peaksdet[] = {0,0,0,0,0,0,0,0,0};
1087 fc = countFC(dest, size, 0);
1088 if (fc!=2 && fc!=4 && fc!=8) return -1;
1089 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
1090
1091 //find first full wave
1092 for (i=160; i < loopCnt; i++){
1093 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1094 if (waveStart == 0) {
1095 waveStart = i+1;
1096 //prnt("DEBUG: waveStart: %d",waveStart);
1097 } else {
1098 waveEnd = i+1;
1099 //prnt("DEBUG: waveEnd: %d",waveEnd);
1100 waveLenCnt = waveEnd-waveStart;
1101 if (waveLenCnt > fc){
1102 firstFullWave = waveStart;
1103 fullWaveLen=waveLenCnt;
1104 break;
1105 }
1106 waveStart=0;
1107 }
1108 }
1109 }
1110 *firstPhaseShift = firstFullWave;
1111 if (g_debugMode == 2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1112
1113 //test each valid clock from greatest to smallest to see which lines up
1114 for (clkCnt=7; clkCnt >= 1 ; clkCnt--){
1115 lastClkBit = firstFullWave; //set end of wave as clock align
1116 waveStart = 0;
1117 errCnt=0;
1118 peakcnt=0;
1119 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
1120
1121 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1122 //top edge of wave = start of new wave
1123 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1124 if (waveStart == 0) {
1125 waveStart = i+1;
1126 waveLenCnt=0;
1127 } else { //waveEnd
1128 waveEnd = i+1;
1129 waveLenCnt = waveEnd-waveStart;
1130 if (waveLenCnt > fc){
1131 //if this wave is a phase shift
1132 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);
1133 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1134 peakcnt++;
1135 lastClkBit+=clk[clkCnt];
1136 } else if (i<lastClkBit+8){
1137 //noise after a phase shift - ignore
1138 } else { //phase shift before supposed to based on clock
1139 errCnt++;
1140 }
1141 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1142 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1143 }
1144 waveStart=i+1;
1145 }
1146 }
1147 }
1148 if (errCnt == 0) return clk[clkCnt];
1149 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt] = errCnt;
1150 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt] = peakcnt;
1151 }
1152 //all tested with errors
1153 //return the highest clk with the most peaks found
1154 uint8_t best = 7;
1155 for (i=7; i >= 1; i--){
1156 if (peaksdet[i] > peaksdet[best])
1157 best = i;
1158
1159 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
1160 }
1161 return clk[best];
1162 }
1163
1164 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1165 //find shortest transition from high to low
1166 size_t i = 0;
1167 size_t transition1 = 0;
1168 int lowestTransition = 255;
1169 bool lastWasHigh = false;
1170
1171 //find first valid beginning of a high or low wave
1172 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1173 ++i;
1174 while ((dest[i] < peak && dest[i] > low) && (i < size))
1175 ++i;
1176 lastWasHigh = (dest[i] >= peak);
1177
1178 if (i==size) return 0;
1179 transition1 = i;
1180
1181 for (;i < size; i++) {
1182 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1183 lastWasHigh = (dest[i] >= peak);
1184 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1185 transition1 = i;
1186 }
1187 }
1188 if (lowestTransition == 255) lowestTransition = 0;
1189 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
1190 return lowestTransition;
1191 }
1192
1193 int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
1194 int bestStart = 0;
1195 return DetectNRZClock_ext(dest, size, clock, &bestStart);
1196 }
1197
1198 //by marshmellow
1199 //detect nrz clock by reading #peaks vs no peaks(or errors)
1200 int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, int *clockStartIdx) {
1201 size_t i = 0;
1202 uint8_t clk[] = {8,16,32,40,50,64,100,128,255};
1203 size_t loopCnt = 4096; //don't need to loop through entire array...
1204
1205 //if we already have a valid clock quit
1206 for (; i < 8; ++i)
1207 if (clk[i] == clock) return clock;
1208
1209 if (size < 20) return 0;
1210 // size must be larger than 20 here
1211 if (size < loopCnt) loopCnt = size-20;
1212
1213 //get high and low peak
1214 int peak, low;
1215 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
1216
1217 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
1218 size_t ii;
1219 uint8_t clkCnt;
1220 uint8_t tol = 0;
1221 uint16_t smplCnt = 0;
1222 int16_t peakcnt = 0;
1223 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1224 uint16_t maxPeak = 255;
1225 bool firstpeak = false;
1226 //test for large clipped waves
1227 for (i=0; i<loopCnt; i++){
1228 if (dest[i] >= peak || dest[i] <= low){
1229 if (!firstpeak) continue;
1230 smplCnt++;
1231 } else {
1232 firstpeak = true;
1233 if (smplCnt > 6 ){
1234 if (maxPeak > smplCnt){
1235 maxPeak = smplCnt;
1236 //prnt("maxPk: %d",maxPeak);
1237 }
1238 peakcnt++;
1239 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1240 smplCnt = 0;
1241 }
1242 }
1243 }
1244 bool errBitHigh = 0;
1245 bool bitHigh = 0;
1246 uint8_t ignoreCnt = 0;
1247 uint8_t ignoreWindow = 4;
1248 bool lastPeakHigh = 0;
1249 int lastBit = 0;
1250 int bestStart[] = {0,0,0,0,0,0,0,0,0};
1251 peakcnt = 0;
1252 //test each valid clock from smallest to greatest to see which lines up
1253 for(clkCnt=0; clkCnt < 8; ++clkCnt){
1254 //ignore clocks smaller than smallest peak
1255 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
1256 //try lining up the peaks by moving starting point (try first 256)
1257 for (ii=20; ii < loopCnt; ++ii){
1258 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1259 peakcnt=0;
1260 bitHigh = false;
1261 ignoreCnt = 0;
1262 lastBit = ii-clk[clkCnt];
1263 //loop through to see if this start location works
1264 for (i = ii; i < size-20; ++i) {
1265 //if we are at a clock bit
1266 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1267 //test high/low
1268 if (dest[i] >= peak || dest[i] <= low) {
1269 //if same peak don't count it
1270 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1271 peakcnt++;
1272 }
1273 lastPeakHigh = (dest[i] >= peak);
1274 bitHigh = true;
1275 errBitHigh = false;
1276 ignoreCnt = ignoreWindow;
1277 lastBit += clk[clkCnt];
1278 } else if (i == lastBit + clk[clkCnt] + tol) {
1279 lastBit += clk[clkCnt];
1280 }
1281 //else if not a clock bit and no peaks
1282 } else if (dest[i] < peak && dest[i] > low){
1283 if (ignoreCnt == 0){
1284 bitHigh=false;
1285 if (errBitHigh==true)
1286 peakcnt--;
1287 errBitHigh=false;
1288 } else {
1289 ignoreCnt--;
1290 }
1291 // else if not a clock bit but we have a peak
1292 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1293 //error bar found no clock...
1294 errBitHigh=true;
1295 }
1296 }
1297 if (peakcnt > peaksdet[clkCnt]) {
1298 bestStart[clkCnt]=ii;
1299 peaksdet[clkCnt] = peakcnt;
1300 }
1301 }
1302 }
1303 }
1304
1305 uint8_t best = 0;
1306 for (int m = 7; m > 0; m--){
1307 if ((peaksdet[m] >= (peaksdet[best]-1)) && (peaksdet[m] <= peaksdet[best]+1) && lowestTransition) {
1308 if (clk[m] > (lowestTransition - (clk[m]/8)) && clk[m] < (lowestTransition + (clk[m]/8))) {
1309 best = m;
1310 }
1311 } else if (peaksdet[m] > peaksdet[best]){
1312 best = m;
1313 }
1314 if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d", clk[m], peaksdet[m], maxPeak, clk[best], lowestTransition);
1315 }
1316 *clockStartIdx = bestStart[best];
1317 return clk[best];
1318 }
1319
1320 // by marshmellow
1321 // convert psk1 demod to psk2 demod
1322 // only transition waves are 1s
1323 void psk1TOpsk2(uint8_t *bits, size_t size) {
1324 uint8_t lastBit = bits[0];
1325 for (size_t i = 1; i < size; i++){
1326 //ignore errors
1327 if (bits[i] == 7) continue;
1328
1329 if (lastBit != bits[i]){
1330 lastBit = bits[i];
1331 bits[i] = 1;
1332 } else {
1333 bits[i] = 0;
1334 }
1335 }
1336 }
1337
1338 // by marshmellow
1339 // convert psk2 demod to psk1 demod
1340 // from only transition waves are 1s to phase shifts change bit
1341 void psk2TOpsk1(uint8_t *bits, size_t size) {
1342 uint8_t phase = 0;
1343 for (size_t i = 0; i < size; i++){
1344 if (bits[i] == 1){
1345 phase ^= 1;
1346 }
1347 bits[i] = phase;
1348 }
1349 }
1350
1351 // redesigned by marshmellow adjusted from existing decode functions
1352 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1353 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1354 {
1355 //26 bit 40134 format (don't know other formats)
1356 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};
1357 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};
1358 size_t startidx = 0;
1359 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1360 // if didn't find preamble try again inverting
1361 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1362 *invert ^= 1;
1363 }
1364 if (*size != 64 && *size != 224) return -2;
1365 if (*invert==1)
1366 for (size_t i = startidx; i < *size; i++)
1367 bitStream[i] ^= 1;
1368
1369 return (int) startidx;
1370 }
1371
1372 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1373 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1374 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
1375 if (justNoise(dest, *size)) return -1;
1376 *clk = DetectNRZClock(dest, *size, *clk);
1377 if (*clk==0) return -2;
1378 size_t i, gLen = 4096;
1379 if (gLen>*size) gLen = *size-20;
1380 int high, low;
1381 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1382
1383 uint8_t bit=0;
1384 //convert wave samples to 1's and 0's
1385 for(i=20; i < *size-20; i++){
1386 if (dest[i] >= high) bit = 1;
1387 if (dest[i] <= low) bit = 0;
1388 dest[i] = bit;
1389 }
1390 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1391 size_t lastBit = 0;
1392 size_t numBits = 0;
1393 for(i=21; i < *size-20; i++) {
1394 //if transition detected or large number of same bits - store the passed bits
1395 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1396 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1397 numBits += (i - lastBit + (*clk/4)) / *clk;
1398 lastBit = i-1;
1399 }
1400 }
1401 *size = numBits;
1402 return 0;
1403 }
1404
1405 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
1406 int firstClockEdge = 0;
1407 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
1408 }
1409
1410 //by marshmellow
1411 //detects the bit clock for FSK given the high and low Field Clocks
1412 uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
1413 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1414 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1415 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1416 uint8_t rfLensFnd = 0;
1417 uint8_t lastFCcnt = 0;
1418 uint16_t fcCounter = 0;
1419 uint16_t rfCounter = 0;
1420 uint8_t firstBitFnd = 0;
1421 size_t i;
1422 if (size == 0) return 0;
1423
1424 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1425 rfLensFnd=0;
1426 fcCounter=0;
1427 rfCounter=0;
1428 firstBitFnd=0;
1429 //prnt("DEBUG: fcTol: %d",fcTol);
1430 // prime i to first peak / up transition
1431 for (i = 160; i < size-20; i++)
1432 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1433 break;
1434
1435 for (; i < size-20; i++){
1436 fcCounter++;
1437 rfCounter++;
1438
1439 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1440 continue;
1441 // else new peak
1442 // if we got less than the small fc + tolerance then set it to the small fc
1443 // if it is inbetween set it to the last counter
1444 if (fcCounter < fcHigh && fcCounter > fcLow)
1445 fcCounter = lastFCcnt;
1446 else if (fcCounter < fcLow+fcTol)
1447 fcCounter = fcLow;
1448 else //set it to the large fc
1449 fcCounter = fcHigh;
1450
1451 //look for bit clock (rf/xx)
1452 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1453 //not the same size as the last wave - start of new bit sequence
1454 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1455 for (int ii=0; ii<15; ii++){
1456 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
1457 rfCnts[ii]++;
1458 rfCounter = 0;
1459 break;
1460 }
1461 }
1462 if (rfCounter > 0 && rfLensFnd < 15){
1463 //prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1464 rfCnts[rfLensFnd]++;
1465 rfLens[rfLensFnd++] = rfCounter;
1466 }
1467 } else {
1468 *firstClockEdge = i;
1469 firstBitFnd++;
1470 }
1471 rfCounter=0;
1472 lastFCcnt=fcCounter;
1473 }
1474 fcCounter=0;
1475 }
1476 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1477
1478 for (i=0; i<15; i++){
1479 //get highest 2 RF values (might need to get more values to compare or compare all?)
1480 if (rfCnts[i]>rfCnts[rfHighest]){
1481 rfHighest3=rfHighest2;
1482 rfHighest2=rfHighest;
1483 rfHighest=i;
1484 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1485 rfHighest3=rfHighest2;
1486 rfHighest2=i;
1487 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1488 rfHighest3=i;
1489 }
1490 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
1491 }
1492 // set allowed clock remainder tolerance to be 1 large field clock length+1
1493 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1494 uint8_t tol1 = fcHigh+1;
1495
1496 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
1497
1498 // loop to find the highest clock that has a remainder less than the tolerance
1499 // compare samples counted divided by
1500 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1501 int ii=7;
1502 for (; ii>=2; ii--){
1503 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1504 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1505 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
1506 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
1507 break;
1508 }
1509 }
1510 }
1511 }
1512
1513 if (ii<2) return 0; // oops we went too far
1514
1515 return clk[ii];
1516 }
1517
1518 //by marshmellow
1519 //countFC is to detect the field clock lengths.
1520 //counts and returns the 2 most common wave lengths
1521 //mainly used for FSK field clock detection
1522 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
1523 {
1524 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1525 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1526 uint8_t fcLensFnd = 0;
1527 uint8_t lastFCcnt = 0;
1528 uint8_t fcCounter = 0;
1529 size_t i;
1530 if (size < 180) return 0;
1531
1532 // prime i to first up transition
1533 for (i = 160; i < size-20; i++)
1534 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1535 break;
1536
1537 for (; i < size-20; i++){
1538 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1539 // new up transition
1540 fcCounter++;
1541 if (fskAdj){
1542 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1543 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1544 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1545 if ((fcCounter==9) || fcCounter==4) fcCounter++;
1546 // save last field clock count (fc/xx)
1547 lastFCcnt = fcCounter;
1548 }
1549 // find which fcLens to save it to:
1550 for (int ii=0; ii<15; ii++){
1551 if (fcLens[ii]==fcCounter){
1552 fcCnts[ii]++;
1553 fcCounter=0;
1554 break;
1555 }
1556 }
1557 if (fcCounter>0 && fcLensFnd<15){
1558 //add new fc length
1559 fcCnts[fcLensFnd]++;
1560 fcLens[fcLensFnd++]=fcCounter;
1561 }
1562 fcCounter=0;
1563 } else {
1564 // count sample
1565 fcCounter++;
1566 }
1567 }
1568
1569 uint8_t best1=14, best2=14, best3=14;
1570 uint16_t maxCnt1=0;
1571 // go through fclens and find which ones are bigest 2
1572 for (i=0; i<15; i++){
1573 // get the 3 best FC values
1574 if (fcCnts[i]>maxCnt1) {
1575 best3=best2;
1576 best2=best1;
1577 maxCnt1=fcCnts[i];
1578 best1=i;
1579 } else if(fcCnts[i]>fcCnts[best2]){
1580 best3=best2;
1581 best2=i;
1582 } else if(fcCnts[i]>fcCnts[best3]){
1583 best3=i;
1584 }
1585 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]);
1586 }
1587 if (fcLens[best1]==0) return 0;
1588 uint8_t fcH=0, fcL=0;
1589 if (fcLens[best1]>fcLens[best2]){
1590 fcH=fcLens[best1];
1591 fcL=fcLens[best2];
1592 } else{
1593 fcH=fcLens[best2];
1594 fcL=fcLens[best1];
1595 }
1596 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1597 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]);
1598 return 0; //lots of waves not psk or fsk
1599 }
1600 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1601
1602 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
1603 if (fskAdj) return fcs;
1604 return fcLens[best1];
1605 }
1606
1607 //by marshmellow - demodulate PSK1 wave
1608 //uses wave lengths (# Samples)
1609 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1610 {
1611 if (size == 0) return -1;
1612 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1613 if (*size<loopCnt) loopCnt = *size;
1614
1615 size_t numBits=0;
1616 uint8_t curPhase = *invert;
1617 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1618 uint16_t fc=0, fullWaveLen=0, tol=1;
1619 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1620 fc = countFC(dest, *size, 1);
1621 uint8_t fc2 = fc >> 8;
1622 if (fc2 == 10) return -1; //fsk found - quit
1623 fc = fc & 0xFF;
1624 if (fc!=2 && fc!=4 && fc!=8) return -1;
1625 //prnt("DEBUG: FC: %d",fc);
1626 *clock = DetectPSKClock(dest, *size, *clock);
1627 if (*clock == 0) return -1;
1628
1629 //find start of modulating data in trace
1630 uint8_t threshold_value = 123; //-5
1631 i = findModStart(dest, *size, threshold_value, fc);
1632
1633 //find first phase shift
1634 int avgWaveVal=0, lastAvgWaveVal=0;
1635 waveStart = i;
1636 for (; i<loopCnt; i++){
1637 // find peak
1638 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1639 waveEnd = i+1;
1640 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1641 waveLenCnt = waveEnd-waveStart;
1642 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1643 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1644 firstFullWave = waveStart;
1645 fullWaveLen=waveLenCnt;
1646 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1647 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
1648 break;
1649 }
1650 waveStart = i+1;
1651 avgWaveVal = 0;
1652 }
1653 avgWaveVal += dest[i+2];
1654 }
1655 if (firstFullWave == 0) {
1656 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1657 // so skip a little to ensure we are past any Start Signal
1658 firstFullWave = 160;
1659 memset(dest, curPhase, firstFullWave / *clock);
1660 } else {
1661 memset(dest, curPhase^1, firstFullWave / *clock);
1662 }
1663 //advance bits
1664 numBits += (firstFullWave / *clock);
1665 //set start of wave as clock align
1666 lastClkBit = firstFullWave;
1667 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
1668 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1669 waveStart = 0;
1670 dest[numBits++] = curPhase; //set first read bit
1671 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1672 //top edge of wave = start of new wave
1673 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1674 if (waveStart == 0) {
1675 waveStart = i+1;
1676 waveLenCnt = 0;
1677 avgWaveVal = dest[i+1];
1678 } else { //waveEnd
1679 waveEnd = i+1;
1680 waveLenCnt = waveEnd-waveStart;
1681 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1682 if (waveLenCnt > fc){
1683 //prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1684 //this wave is a phase shift
1685 //prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1686 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1687 curPhase ^= 1;
1688 dest[numBits++] = curPhase;
1689 lastClkBit += *clock;
1690 } else if (i < lastClkBit+10+fc){
1691 //noise after a phase shift - ignore
1692 } else { //phase shift before supposed to based on clock
1693 errCnt++;
1694 dest[numBits++] = 7;
1695 }
1696 } else if (i+1 > lastClkBit + *clock + tol + fc){
1697 lastClkBit += *clock; //no phase shift but clock bit
1698 dest[numBits++] = curPhase;
1699 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1700 errCnt2++;
1701 if(errCnt2 > 101) return errCnt2;
1702 }
1703 avgWaveVal = 0;
1704 waveStart = i+1;
1705 }
1706 }
1707 avgWaveVal += dest[i+1];
1708 }
1709 *size = numBits;
1710 return errCnt;
1711 }
1712
1713 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1714 size_t ststart = 0, stend = 0;
1715 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1716 }
1717
1718 //by marshmellow
1719 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1720 bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
1721 size_t bufsize = *size;
1722 //need to loop through all samples and identify our clock, look for the ST pattern
1723 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1724 int clk = 0;
1725 int tol = 0;
1726 int i, j, skip, start, end, low, high, minClk, waveStart;
1727 bool complete = false;
1728 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1729 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
1730 size_t testsize = (bufsize < 512) ? bufsize : 512;
1731 int phaseoff = 0;
1732 high = low = 128;
1733 memset(tmpbuff, 0, sizeof(tmpbuff));
1734 memset(waveLen, 0, sizeof(waveLen));
1735
1736
1737 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1738 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1739 return false; //just noise
1740 }
1741 i = 0;
1742 j = 0;
1743 minClk = 255;
1744 // get to first full low to prime loop and skip incomplete first pulse
1745 while ((buffer[i] < high) && (i < bufsize))
1746 ++i;
1747 while ((buffer[i] > low) && (i < bufsize))
1748 ++i;
1749 skip = i;
1750
1751 // populate tmpbuff buffer with pulse lengths
1752 while (i < bufsize) {
1753 // measure from low to low
1754 while ((buffer[i] > low) && (i < bufsize))
1755 ++i;
1756 start= i;
1757 while ((buffer[i] < high) && (i < bufsize))
1758 ++i;
1759 //first high point for this wave
1760 waveStart = i;
1761 while ((buffer[i] > low) && (i < bufsize))
1762 ++i;
1763 if (j >= (bufsize/32)) {
1764 break;
1765 }
1766 waveLen[j] = i - waveStart; //first high to first low
1767 tmpbuff[j++] = i - start;
1768 if (i-start < minClk && i < bufsize) {
1769 minClk = i - start;
1770 }
1771 }
1772 // set clock - might be able to get this externally and remove this work...
1773 if (!clk) {
1774 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1775 tol = fndClk[clkCnt]/8;
1776 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1777 clk=fndClk[clkCnt];
1778 break;
1779 }
1780 }
1781 // clock not found - ERROR
1782 if (!clk) {
1783 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1784 return false;
1785 }
1786 } else tol = clk/8;
1787
1788 *foundclock = clk;
1789
1790 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1791 start = -1;
1792 for (i = 0; i < j - 4; ++i) {
1793 skip += tmpbuff[i];
1794 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1795 if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
1796 if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
1797 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1798 start = i + 3;
1799 break;
1800 }
1801 }
1802 }
1803 }
1804 }
1805 // first ST not found - ERROR
1806 if (start < 0) {
1807 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1808 return false;
1809 } else {
1810 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
1811 }
1812 if (waveLen[i+2] > clk*1+tol)
1813 phaseoff = 0;
1814 else
1815 phaseoff = clk/2;
1816
1817 // skip over the remainder of ST
1818 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1819
1820 // now do it again to find the end
1821 end = skip;
1822 for (i += 3; i < j - 4; ++i) {
1823 end += tmpbuff[i];
1824 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1825 if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
1826 if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
1827 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1828 complete = true;
1829 break;
1830 }
1831 }
1832 }
1833 }
1834 }
1835 end -= phaseoff;
1836 //didn't find second ST - ERROR
1837 if (!complete) {
1838 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1839 return false;
1840 }
1841 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);
1842 //now begin to trim out ST so we can use normal demod cmds
1843 start = skip;
1844 size_t datalen = end - start;
1845 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1846 if ( clk - (datalen % clk) <= clk/8) {
1847 // padd the amount off - could be problematic... but shouldn't happen often
1848 datalen += clk - (datalen % clk);
1849 } else if ( (datalen % clk) <= clk/8 ) {
1850 // padd the amount off - could be problematic... but shouldn't happen often
1851 datalen -= datalen % clk;
1852 } else {
1853 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1854 return false;
1855 }
1856 // if datalen is less than one t55xx block - ERROR
1857 if (datalen/clk < 8*4) {
1858 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1859 return false;
1860 }
1861 size_t dataloc = start;
1862 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1863 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1864 for ( i=0; i <= (clk/8); ++i ) {
1865 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1866 dataloc -= i;
1867 break;
1868 }
1869 }
1870 }
1871
1872 size_t newloc = 0;
1873 i=0;
1874 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1875 bool firstrun = true;
1876 // warning - overwriting buffer given with raw wave data with ST removed...
1877 while ( dataloc < bufsize-(clk/2) ) {
1878 //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)
1879 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1880 for(i=0; i < clk/2-tol; ++i) {
1881 buffer[dataloc+i] = high+5;
1882 }
1883 } //test for single sample outlier (high between two lows) in the case of very strong waves
1884 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1885 buffer[dataloc] = buffer[dataloc+2];
1886 buffer[dataloc+1] = buffer[dataloc+2];
1887 }
1888 if (firstrun) {
1889 *stend = dataloc;
1890 *ststart = dataloc-(clk*4);
1891 firstrun=false;
1892 }
1893 for (i=0; i<datalen; ++i) {
1894 if (i+newloc < bufsize) {
1895 if (i+newloc < dataloc)
1896 buffer[i+newloc] = buffer[dataloc];
1897
1898 dataloc++;
1899 }
1900 }
1901 newloc += i;
1902 //skip next ST - we just assume it will be there from now on...
1903 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1904 dataloc += clk*4;
1905 }
1906 *size = newloc;
1907 return true;
1908 }
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