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