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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"
18 # include "cmdparser.h"
19 # include "cmddata.h"
20 # define prnt PrintAndLog
21 # define sgc SetGraphClock
22 #else
23 uint8_t g_debugMode=0;
24 # define prnt dummy
25 # define sgc dummy_sgc
26 #endif
27
28 void SetGraphClock(int clock, int startidx){
29 PlotClock = clock;
30 PlockClockStartIndex = startidx;
31 }
32
33 //test samples are not just noise
34 uint8_t justNoise(uint8_t *bits, size_t size) {
35 #define THRESHOLD 123
36 uint8_t val = 1;
37 for(size_t idx = 0; idx < size && val; idx++)
38 val = bits[idx] < THRESHOLD;
39 return val;
40 }
41
42 //by marshmellow
43 //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
44 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
45 {
46 *high=0;
47 *low=255;
48 // get high and low thresholds
49 for (size_t i=0; i < size; i++){
50 if (BitStream[i] > *high) *high = BitStream[i];
51 if (BitStream[i] < *low) *low = BitStream[i];
52 }
53 if (*high < 123) return -1; // just noise
54 *high = ((*high-128)*fuzzHi + 12800)/100;
55 *low = ((*low-128)*fuzzLo + 12800)/100;
56 return 1;
57 }
58
59 // by marshmellow
60 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
61 // returns 1 if passed
62 uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
63 {
64 uint8_t ans = 0;
65 for (uint8_t i = 0; i < bitLen; i++){
66 ans ^= ((bits >> i) & 1);
67 }
68 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
69 return (ans == pType);
70 }
71
72 //by marshmellow
73 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
74 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
75 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
76 {
77 uint32_t parityWd = 0;
78 size_t j = 0, bitCnt = 0;
79 for (int word = 0; word < (bLen); word += pLen){
80 for (int bit=0; bit < pLen; bit++){
81 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
82 BitStream[j++] = (BitStream[startIdx+word+bit]);
83 }
84 if (word+pLen > bLen) break;
85
86 j--; // overwrite parity with next data
87 // if parity fails then return 0
88 switch (pType) {
89 case 3: if (BitStream[j]==1) { return 0; } break; //should be 0 spacer bit
90 case 2: if (BitStream[j]==0) { return 0; } break; //should be 1 spacer bit
91 default: if (parityTest(parityWd, pLen, pType) == 0) { return 0; } break; //test parity
92 }
93 bitCnt += (pLen-1);
94 parityWd = 0;
95 }
96 // if we got here then all the parities passed
97 //return ID start index and size
98 return bitCnt;
99 }
100
101 // by marshmellow
102 // takes a array of binary values, length of bits per parity (includes parity bit),
103 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
104 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
105 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
106 {
107 uint32_t parityWd = 0;
108 size_t j = 0, bitCnt = 0;
109 for (int word = 0; word < sourceLen; word+=pLen-1) {
110 for (int bit=0; bit < pLen-1; bit++){
111 parityWd = (parityWd << 1) | BitSource[word+bit];
112 dest[j++] = (BitSource[word+bit]);
113 }
114
115 // if parity fails then return 0
116 switch (pType) {
117 case 3: dest[j++]=0; break; // marker bit which should be a 0
118 case 2: dest[j++]=1; break; // marker bit which should be a 1
119 default:
120 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
121 break;
122 }
123 bitCnt += pLen;
124 parityWd = 0;
125 }
126 // if we got here then all the parities passed
127 //return ID start index and size
128 return bitCnt;
129 }
130
131 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
132 {
133 uint32_t num = 0;
134 for(int i = 0 ; i < numbits ; i++) {
135 num = (num << 1) | (*src);
136 src++;
137 }
138 return num;
139 }
140
141 //least significant bit first
142 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
143 {
144 uint32_t num = 0;
145 for(int i = 0 ; i < numbits ; i++) {
146 num = (num << 1) | *(src + (numbits-(i+1)));
147 }
148 return num;
149 }
150
151 //by marshmellow
152 // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
153 bool preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx){
154 return preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false);
155 }
156 //by marshmellow
157 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
158 // param @findone: look for a repeating preamble or only the first.
159 // em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
160 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone)
161 {
162 // Sanity check. If preamble length is bigger than bitstream length.
163 if ( *size <= pLen ) return false;
164
165 uint8_t foundCnt = 0;
166 for (int idx = 0; idx < *size - pLen; idx++){
167 if (memcmp(BitStream+idx, preamble, pLen) == 0){
168 if (g_debugMode) prnt("DEBUG: preamble found at %i", idx);
169 //first index found
170 foundCnt++;
171 if (foundCnt == 1){
172 *startIdx = idx;
173 if (findone) return true;
174 }
175 if (foundCnt == 2){
176 *size = idx - *startIdx;
177 return true;
178 }
179 }
180 }
181 return false;
182 }
183
184 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
185 size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
186 size_t i = 0;
187 size_t waveSizeCnt = 0;
188 uint8_t thresholdCnt = 0;
189 bool isAboveThreshold = dest[i++] >= threshold_value;
190 for (; i < size-20; i++ ) {
191 if(dest[i] < threshold_value && isAboveThreshold) {
192 thresholdCnt++;
193 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
194 isAboveThreshold = false;
195 waveSizeCnt = 0;
196 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
197 thresholdCnt++;
198 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
199 isAboveThreshold = true;
200 waveSizeCnt = 0;
201 } else {
202 waveSizeCnt++;
203 }
204 if (thresholdCnt > 10) break;
205 }
206 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
207 return i;
208 }
209
210 //by marshmellow
211 //takes 1s and 0s and searches for EM410x format - output EM ID
212 // actually, no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
213 int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
214 {
215 // sanity check
216 if (*size < 64) return -3;
217 if (BitStream[1] > 1) return -1;
218
219 uint8_t fmtlen;
220 *startIdx = 0;
221
222 // preamble 0111111111
223 // include 0 in front to help get start pos
224 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
225 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
226 return -2;
227
228 //XL and normal size.
229 if (*size != 64 && *size != 128) return -3;
230
231 fmtlen = (*size == 128) ? 22 : 10;
232
233 //skip last 4bit parity row for simplicity
234 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);
235
236 switch (*size) {
237 case 40: {
238 // std em410x format
239 *hi = 0;
240 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
241 break;
242 }
243 case 88: {
244 // long em format
245 *hi = (bytebits_to_byte(BitStream, 24));
246 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
247 break;
248 }
249 default: return -4;
250 }
251 return 1;
252 }
253
254 //by marshmellow
255 //demodulates strong heavily clipped samples
256 //RETURN: num of errors. if 0, is ok.
257 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
258 {
259 size_t bitCnt=0, smplCnt=0, errCnt=0;
260 uint8_t waveHigh = 0;
261 for (size_t i=0; i < *size; i++){
262 if (BinStream[i] >= high && waveHigh){
263 smplCnt++;
264 } else if (BinStream[i] <= low && !waveHigh){
265 smplCnt++;
266 } else { //transition
267 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
268
269 if (smplCnt > clk-(clk/4)-1) { //full clock
270 if (smplCnt > clk + (clk/4)+1) { //too many samples
271 errCnt++;
272 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
273 BinStream[bitCnt++] = 7;
274 } else if (waveHigh) {
275 BinStream[bitCnt++] = invert;
276 BinStream[bitCnt++] = invert;
277 } else if (!waveHigh) {
278 BinStream[bitCnt++] = invert ^ 1;
279 BinStream[bitCnt++] = invert ^ 1;
280 }
281 waveHigh ^= 1;
282 smplCnt = 0;
283 } else if (smplCnt > (clk/2) - (clk/4)-1) {
284 if (waveHigh) {
285 BinStream[bitCnt++] = invert;
286 } else if (!waveHigh) {
287 BinStream[bitCnt++] = invert ^ 1;
288 }
289 waveHigh ^= 1;
290 smplCnt = 0;
291 } else if (!bitCnt) {
292 //first bit
293 waveHigh = (BinStream[i] >= high);
294 smplCnt = 1;
295 } else {
296 smplCnt++;
297 //transition bit oops
298 }
299 } else { //haven't hit new high or new low yet
300 smplCnt++;
301 }
302 }
303 }
304 *size = bitCnt;
305 return errCnt;
306 }
307
308 //by marshmellow
309 void askAmp(uint8_t *BitStream, size_t size)
310 {
311 uint8_t last = 128;
312 for(size_t i = 1; i < size; ++i){
313 if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
314 last = 255;
315 else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
316 last = 0;
317
318 BitStream[i] = last;
319 }
320 }
321
322 //by marshmellow
323 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
324 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
325 {
326 if (*size==0) return -1;
327 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
328 if (*clk==0 || start < 0) return -3;
329 if (*invert != 1) *invert = 0;
330 if (amp==1) askAmp(BinStream, *size);
331 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
332
333 sgc(*clk, start);
334
335 uint8_t initLoopMax = 255;
336 if (initLoopMax > *size) initLoopMax = *size;
337 // Detect high and lows
338 //25% clip in case highs and lows aren't clipped [marshmellow]
339 int high, low;
340 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
341 return -2; //just noise
342
343 size_t errCnt = 0;
344 // if clean clipped waves detected run alternate demod
345 if (DetectCleanAskWave(BinStream, *size, high, low)) {
346 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
347 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
348 if (askType) //askman
349 return manrawdecode(BinStream, size, 0);
350 //askraw
351 return errCnt;
352 }
353 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
354
355 int lastBit; //set first clock check - can go negative
356 size_t i, bitnum = 0; //output counter
357 uint8_t midBit = 0;
358 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
359 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
360 size_t MaxBits = 3072; //max bits to collect
361 lastBit = start - *clk;
362
363 for (i = start; i < *size; ++i) {
364 if (i-lastBit >= *clk-tol){
365 if (BinStream[i] >= high) {
366 BinStream[bitnum++] = *invert;
367 } else if (BinStream[i] <= low) {
368 BinStream[bitnum++] = *invert ^ 1;
369 } else if (i-lastBit >= *clk+tol) {
370 if (bitnum > 0) {
371 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
372 BinStream[bitnum++]=7;
373 errCnt++;
374 }
375 } else { //in tolerance - looking for peak
376 continue;
377 }
378 midBit = 0;
379 lastBit += *clk;
380 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
381 if (BinStream[i] >= high) {
382 BinStream[bitnum++] = *invert;
383 } else if (BinStream[i] <= low) {
384 BinStream[bitnum++] = *invert ^ 1;
385 } else if (i-lastBit >= *clk/2+tol) {
386 BinStream[bitnum] = BinStream[bitnum-1];
387 bitnum++;
388 } else { //in tolerance - looking for peak
389 continue;
390 }
391 midBit = 1;
392 }
393 if (bitnum >= MaxBits) break;
394 }
395 *size = bitnum;
396 return errCnt;
397 }
398 //by marshmellow
399 //take 10 and 01 and manchester decode
400 //run through 2 times and take least errCnt
401 int manrawdecode(uint8_t *BitStream, size_t *size, uint8_t invert){
402
403 // sanity check
404 if (*size < 16) return -1;
405
406 int errCnt = 0, bestErr = 1000;
407 uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;
408 size_t i, k;
409
410 //find correct start position [alignment]
411 for (k = 0; k < 2; ++k){
412 for (i = k; i < *size-3; i += 2) {
413 if (BitStream[i] == BitStream[i+1])
414 errCnt++;
415 }
416 if (bestErr > errCnt){
417 bestErr = errCnt;
418 bestRun = k;
419 }
420 errCnt = 0;
421 }
422
423 //decode
424 for (i = bestRun; i < *size-3; i += 2){
425 if (BitStream[i] == 1 && (BitStream[i+1] == 0)){
426 BitStream[bitnum++] = invert;
427 } else if ((BitStream[i] == 0) && BitStream[i+1] == 1){
428 BitStream[bitnum++] = invert^1;
429 } else {
430 BitStream[bitnum++] = 7;
431 }
432 if (bitnum > MaxBits) break;
433 }
434 *size = bitnum;
435 return bestErr;
436 }
437
438 uint32_t manchesterEncode2Bytes(uint16_t datain) {
439 uint32_t output = 0;
440 uint8_t curBit = 0;
441 for (uint8_t i=0; i<16; i++) {
442 curBit = (datain >> (15-i) & 1);
443 output |= (1<<(((15-i)*2)+curBit));
444 }
445 return output;
446 }
447
448 //by marshmellow
449 //encode binary data into binary manchester
450 int ManchesterEncode(uint8_t *BitStream, size_t size)
451 {
452 size_t modIdx=20000, i=0;
453 if (size>modIdx) return -1;
454 for (size_t idx=0; idx < size; idx++){
455 BitStream[idx+modIdx++] = BitStream[idx];
456 BitStream[idx+modIdx++] = BitStream[idx]^1;
457 }
458 for (; i<(size*2); i++){
459 BitStream[i] = BitStream[i+20000];
460 }
461 return i;
462 }
463
464 //by marshmellow
465 //take 01 or 10 = 1 and 11 or 00 = 0
466 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
467 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
468 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
469 {
470 uint16_t bitnum = 0;
471 uint16_t errCnt = 0;
472 size_t i = offset;
473 uint16_t MaxBits=512;
474 //if not enough samples - error
475 if (*size < 51) return -1;
476 //check for phase change faults - skip one sample if faulty
477 uint8_t offsetA = 1, offsetB = 1;
478 for (; i<48; i+=2){
479 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
480 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
481 }
482 if (!offsetA && offsetB) offset++;
483 for (i=offset; i<*size-3; i+=2){
484 //check for phase error
485 if (BitStream[i+1]==BitStream[i+2]) {
486 BitStream[bitnum++]=7;
487 errCnt++;
488 }
489 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
490 BitStream[bitnum++]=1^invert;
491 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
492 BitStream[bitnum++]=invert;
493 } else {
494 BitStream[bitnum++]=7;
495 errCnt++;
496 }
497 if(bitnum>MaxBits) break;
498 }
499 *size=bitnum;
500 return errCnt;
501 }
502
503 // by marshmellow
504 // demod gProxIIDemod
505 // error returns as -x
506 // success returns start position in BitStream
507 // BitStream must contain previously askrawdemod and biphasedemoded data
508 int gProxII_Demod(uint8_t BitStream[], size_t *size)
509 {
510 size_t startIdx=0;
511 uint8_t preamble[] = {1,1,1,1,1,0};
512
513 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx))
514 return -3; //preamble not found
515
516 if (*size != 96) return -2; //should have found 96 bits
517
518 //check first 6 spacer bits to verify format
519 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
520 //confirmed proper separator bits found
521 //return start position
522 return (int) startIdx;
523 }
524 return -5; //spacer bits not found - not a valid gproxII
525 }
526
527 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
528 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
529 {
530 size_t last_transition = 0;
531 size_t idx = 1;
532 if (fchigh==0) fchigh=10;
533 if (fclow==0) fclow=8;
534 //set the threshold close to 0 (graph) or 128 std to avoid static
535 uint8_t threshold_value = 123;
536 size_t preLastSample = 0;
537 size_t LastSample = 0;
538 size_t currSample = 0;
539 if ( size < 1024 ) return 0; // not enough samples
540
541 //find start of modulating data in trace
542 idx = findModStart(dest, size, threshold_value, fchigh);
543
544 // Need to threshold first sample
545 if(dest[idx] < threshold_value) dest[0] = 0;
546 else dest[0] = 1;
547 idx++;
548
549 size_t numBits = 0;
550 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
551 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
552 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
553 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
554 for(; idx < size-20; idx++) {
555 // threshold current value
556
557 if (dest[idx] < threshold_value) dest[idx] = 0;
558 else dest[idx] = 1;
559
560 // Check for 0->1 transition
561 if (dest[idx-1] < dest[idx]) {
562 preLastSample = LastSample;
563 LastSample = currSample;
564 currSample = idx-last_transition;
565 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
566 //do nothing with extra garbage
567 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
568 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
569 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
570 dest[numBits-1]=1;
571 }
572 dest[numBits++]=1;
573
574 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
575 //do nothing with beginning garbage and reset.. should be rare..
576 numBits = 0;
577 } 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)
578 dest[numBits++]=1;
579 } else { //9+ = 10 sample waves (or 6+ = 7)
580 dest[numBits++]=0;
581 }
582 last_transition = idx;
583 }
584 }
585 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
586 }
587
588 //translate 11111100000 to 10
589 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
590 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
591 uint8_t invert, uint8_t fchigh, uint8_t fclow)
592 {
593 uint8_t lastval=dest[0];
594 size_t idx=0;
595 size_t numBits=0;
596 uint32_t n=1;
597 for( idx=1; idx < size; idx++) {
598 n++;
599 if (dest[idx]==lastval) continue; //skip until we hit a transition
600
601 //find out how many bits (n) we collected
602 //if lastval was 1, we have a 1->0 crossing
603 if (dest[idx-1]==1) {
604 n = (n * fclow + rfLen/2) / rfLen;
605 } else {// 0->1 crossing
606 n = (n * fchigh + rfLen/2) / rfLen;
607 }
608 if (n == 0) n = 1;
609
610 //add to our destination the bits we collected
611 memset(dest+numBits, dest[idx-1]^invert , n);
612 numBits += n;
613 n=0;
614 lastval=dest[idx];
615 }//end for
616 // if valid extra bits at the end were all the same frequency - add them in
617 if (n > rfLen/fchigh) {
618 if (dest[idx-2]==1) {
619 n = (n * fclow + rfLen/2) / rfLen;
620 } else {
621 n = (n * fchigh + rfLen/2) / rfLen;
622 }
623 memset(dest+numBits, dest[idx-1]^invert , n);
624 numBits += n;
625 }
626 return numBits;
627 }
628
629 //by marshmellow (from holiman's base)
630 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
631 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
632 {
633 // FSK demodulator
634 size = fsk_wave_demod(dest, size, fchigh, fclow);
635 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
636 return size;
637 }
638
639 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
640 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
641 {
642 if (justNoise(dest, *size)) return -1;
643
644 size_t numStart=0, size2 = *size, startIdx=0;
645 // FSK demodulator
646 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
647 if (*size < 96*2) return -2;
648 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
649 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
650 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
651 return -3; //preamble not found
652
653 numStart = startIdx + sizeof(preamble);
654 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
655 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
656 if (dest[idx] == dest[idx+1]){
657 return -4; //not manchester data
658 }
659 *hi2 = (*hi2<<1)|(*hi>>31);
660 *hi = (*hi<<1)|(*lo>>31);
661 //Then, shift in a 0 or one into low
662 *lo <<= 1;
663 if (dest[idx] && !dest[idx+1]) // 1 0
664 *lo |= 1;
665 else // 0 1
666 *lo |= 0;
667 }
668 return (int)startIdx;
669 }
670
671 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
672 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
673 {
674 if (justNoise(dest, *size)) return -1;
675
676 size_t numStart=0, size2 = *size, startIdx=0;
677 // FSK demodulator
678 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
679 if (*size < 96) return -2;
680
681 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
682 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
683 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
684 return -3; //preamble not found
685
686 numStart = startIdx + sizeof(preamble);
687 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
688 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
689 if (dest[idx] == dest[idx+1])
690 return -4; //not manchester data
691 *hi2 = (*hi2<<1)|(*hi>>31);
692 *hi = (*hi<<1)|(*lo>>31);
693 //Then, shift in a 0 or one into low
694 if (dest[idx] && !dest[idx+1]) // 1 0
695 *lo=(*lo<<1)|1;
696 else // 0 1
697 *lo=(*lo<<1)|0;
698 }
699 return (int)startIdx;
700 }
701
702 int IOdemodFSK(uint8_t *dest, size_t size)
703 {
704 if (justNoise(dest, size)) return -1;
705 //make sure buffer has data
706 if (size < 66*64) return -2;
707 // FSK demodulator
708 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
709 if (size < 65) return -3; //did we get a good demod?
710 //Index map
711 //0 10 20 30 40 50 60
712 //| | | | | | |
713 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
714 //-----------------------------------------------------------------------------
715 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
716 //
717 //XSF(version)facility:codeone+codetwo
718 //Handle the data
719 size_t startIdx = 0;
720 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
721 if (! preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx))
722 return -4; //preamble not found
723
724 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
725 //confirmed proper separator bits found
726 //return start position
727 return (int) startIdx;
728 }
729 return -5;
730 }
731
732 // by marshmellow
733 // find viking preamble 0xF200 in already demoded data
734 int VikingDemod_AM(uint8_t *dest, size_t *size) {
735 //make sure buffer has data
736 if (*size < 64*2) return -2;
737 size_t startIdx = 0;
738 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};
739 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
740 return -4; //preamble not found
741
742 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^
743 bytebits_to_byte(dest+startIdx+8,8) ^
744 bytebits_to_byte(dest+startIdx+16,8) ^
745 bytebits_to_byte(dest+startIdx+24,8) ^
746 bytebits_to_byte(dest+startIdx+32,8) ^
747 bytebits_to_byte(dest+startIdx+40,8) ^
748 bytebits_to_byte(dest+startIdx+48,8) ^
749 bytebits_to_byte(dest+startIdx+56,8);
750 if ( checkCalc != 0xA8 ) return -5;
751 if (*size != 64) return -6;
752 //return start position
753 return (int)startIdx;
754 }
755
756 // by iceman
757 // find Visa2000 preamble in already demoded data
758 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
759 if (*size < 96) return -1; //make sure buffer has data
760 size_t startIdx = 0;
761 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};
762 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
763 return -2; //preamble not found
764 if (*size != 96) return -3; //wrong demoded size
765 //return start position
766 return (int)startIdx;
767 }
768 // by iceman
769 // find Noralsy preamble in already demoded data
770 int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
771 if (*size < 96) return -1; //make sure buffer has data
772 size_t startIdx = 0;
773 uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};
774 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
775 return -2; //preamble not found
776 if (*size != 96) return -3; //wrong demoded size
777 //return start position
778 return (int)startIdx;
779 }
780 // find presco preamble 0x10D in already demoded data
781 int PrescoDemod(uint8_t *dest, size_t *size) {
782 if (*size < 128*2) return -1; //make sure buffer has data
783 size_t startIdx = 0;
784 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};
785 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
786 return -2; //preamble not found
787 if (*size != 128) return -3; //wrong demoded size
788 //return start position
789 return (int)startIdx;
790 }
791
792 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
793 // BitStream must contain previously askrawdemod and biphasedemoded data
794 int FDXBdemodBI(uint8_t *dest, size_t *size) {
795 if (*size < 128*2) return -1; //make sure buffer has enough data
796 size_t startIdx = 0;
797 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
798 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
799 return -2; //preamble not found
800 if (*size != 128) return -3; //wrong demoded size
801 //return start position
802 return (int)startIdx;
803 }
804
805 // ASK/Diphase fc/64 (inverted Biphase)
806 // Note: this i s not a demod, this is only a detection
807 // the parameter *dest needs to be demoded before call
808 // 0xFFFF preamble, 64bits
809 int JablotronDemod(uint8_t *dest, size_t *size){
810 if (*size < 64*2) return -1; //make sure buffer has enough data
811 size_t startIdx = 0;
812 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
813 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
814 return -2; //preamble not found
815 if (*size != 64) return -3; // wrong demoded size
816
817 uint8_t checkchksum = 0;
818 for (int i=16; i < 56; i += 8) {
819 checkchksum += bytebits_to_byte(dest+startIdx+i,8);
820 }
821 checkchksum ^= 0x3A;
822 uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
823 if ( checkchksum != crc ) return -5;
824 return (int)startIdx;
825 }
826
827 // by marshmellow
828 // FSK Demod then try to locate an AWID ID
829 int AWIDdemodFSK(uint8_t *dest, size_t *size)
830 {
831 //make sure buffer has enough data
832 if (*size < 96*50) return -1;
833
834 if (justNoise(dest, *size)) return -2;
835
836 // FSK demodulator
837 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
838 if (*size < 96) return -3; //did we get a good demod?
839
840 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
841 size_t startIdx = 0;
842 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
843 return -4; //preamble not found
844 if (*size != 96) return -5;
845 return (int)startIdx;
846 }
847
848 // by marshmellow
849 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
850 int PyramiddemodFSK(uint8_t *dest, size_t *size)
851 {
852 //make sure buffer has data
853 if (*size < 128*50) return -5;
854
855 //test samples are not just noise
856 if (justNoise(dest, *size)) return -1;
857
858 // FSK demodulator
859 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
860 if (*size < 128) return -2; //did we get a good demod?
861 size_t startIdx = 0;
862 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};
863 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
864 return -4; //preamble not found
865 if (*size != 128) return -3;
866 return (int)startIdx;
867 }
868
869 // find nedap preamble in already demoded data
870 int NedapDemod(uint8_t *dest, size_t *size) {
871 //make sure buffer has data
872 if (*size < 128) return -3;
873
874 size_t startIdx = 0;
875 //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
876 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
877 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
878 return -4; //preamble not found
879 return (int) startIdx;
880 }
881
882 // Find IDTEC PSK1, RF Preamble == 0x4944544B, Demodsize 64bits
883 // by iceman
884 int IdteckDemodPSK(uint8_t *dest, size_t *size) {
885 //make sure buffer has data
886 if (*size < 64*2) return -1;
887 size_t startIdx = 0;
888 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};
889 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
890 return -2; //preamble not found
891 if (*size != 64) return -3; // wrong demoded size
892 return (int) startIdx;
893 }
894
895 // by marshmellow
896 // to detect a wave that has heavily clipped (clean) samples
897 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
898 {
899 bool allArePeaks = true;
900 uint16_t cntPeaks=0;
901 size_t loopEnd = 512+160;
902 if (loopEnd > size) loopEnd = size;
903 for (size_t i=160; i<loopEnd; i++){
904 if (dest[i]>low && dest[i]<high)
905 allArePeaks = false;
906 else
907 cntPeaks++;
908 }
909 if (!allArePeaks){
910 if (cntPeaks > 300) return true;
911 }
912 return allArePeaks;
913 }
914 // by marshmellow
915 // to help detect clocks on heavily clipped samples
916 // based on count of low to low
917 int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock)
918 {
919 uint8_t clocks[] = {8,16,32,40,50,64,128};
920 size_t startwave;
921 size_t i = 100;
922 size_t minClk = 255;
923 int shortestWaveIdx = 0;
924 // get to first full low to prime loop and skip incomplete first pulse
925 while ((dest[i] < high) && (i < size))
926 ++i;
927 while ((dest[i] > low) && (i < size))
928 ++i;
929
930 // loop through all samples
931 while (i < size) {
932 // measure from low to low
933 while ((dest[i] > low) && (i < size))
934 ++i;
935 startwave= i;
936 while ((dest[i] < high) && (i < size))
937 ++i;
938 while ((dest[i] > low) && (i < size))
939 ++i;
940 //get minimum measured distance
941 if (i-startwave < minClk && i < size) {
942 minClk = i - startwave;
943 shortestWaveIdx = startwave;
944 }
945 }
946 // set clock
947 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
948 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
949 if (minClk >= clocks[clkCnt]-(clocks[clkCnt]/8) && minClk <= clocks[clkCnt]+1)
950 *clock = clocks[clkCnt];
951 return shortestWaveIdx;
952 }
953 return 0;
954 }
955
956 // by marshmellow
957 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
958 // maybe somehow adjust peak trimming value based on samples to fix?
959 // return start index of best starting position for that clock and return clock (by reference)
960 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
961 {
962 size_t i = 1;
963 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
964 uint8_t clkEnd = 9;
965 uint8_t loopCnt = 255; //don't need to loop through entire array...
966 if (size <= loopCnt + 60) return -1; //not enough samples
967 size -= 60; //sometimes there is a strange end wave - filter out this....
968 //if we already have a valid clock
969 uint8_t clockFnd = 0;
970 for (; i < clkEnd; ++i)
971 if (clk[i] == *clock) clockFnd = i;
972 //clock found but continue to find best startpos
973
974 //get high and low peak
975 int peak, low;
976 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
977
978 //test for large clean peaks
979 if (!clockFnd){
980 if (DetectCleanAskWave(dest, size, peak, low)==1){
981 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
982 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i", clock ,ans);
983 if (ans > 0){
984 return ans; // return shortest wave start pos
985 }
986 }
987 }
988 uint8_t ii;
989 uint8_t clkCnt, tol = 0;
990 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
991 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
992 size_t errCnt = 0;
993 size_t arrLoc, loopEnd;
994
995 if (clockFnd > 0) {
996 clkCnt = clockFnd;
997 clkEnd = clockFnd+1;
998 } else {
999 clkCnt = 1;
1000 }
1001
1002 //test each valid clock from smallest to greatest to see which lines up
1003 for (; clkCnt < clkEnd; clkCnt++) {
1004 if (clk[clkCnt] <= 32) {
1005 tol=1;
1006 } else {
1007 tol=0;
1008 }
1009 //if no errors allowed - keep start within the first clock
1010 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128)
1011 loopCnt = clk[clkCnt] * 2;
1012
1013 bestErr[clkCnt] = 1000;
1014
1015 //try lining up the peaks by moving starting point (try first few clocks)
1016 for (ii=0; ii < loopCnt; ii++){
1017 if (dest[ii] < peak && dest[ii] > low) continue;
1018
1019 errCnt = 0;
1020 // now that we have the first one lined up test rest of wave array
1021 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
1022 for (i=0; i < loopEnd; ++i){
1023 arrLoc = ii + (i * clk[clkCnt]);
1024 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
1025 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
1026 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
1027 }else{ //error no peak detected
1028 errCnt++;
1029 }
1030 }
1031 //if we found no errors then we can stop here and a low clock (common clocks)
1032 // this is correct one - return this clock
1033 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
1034 if (errCnt==0 && clkCnt<7) {
1035 if (!clockFnd) *clock = clk[clkCnt];
1036 return ii;
1037 }
1038 //if we found errors see if it is lowest so far and save it as best run
1039 if (errCnt < bestErr[clkCnt]) {
1040 bestErr[clkCnt] = errCnt;
1041 bestStart[clkCnt] = ii;
1042 }
1043 }
1044 }
1045 uint8_t k;
1046 uint8_t best = 0;
1047 for (k=1; k < clkEnd; ++k){
1048 if (bestErr[k] < bestErr[best]){
1049 if (bestErr[k] == 0) bestErr[k]=1;
1050 // current best bit to error ratio vs new bit to error ratio
1051 if ( (size/clk[best])/bestErr[best] < (size/clk[k])/bestErr[k] ){
1052 best = k;
1053 }
1054 }
1055 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]);
1056 }
1057 if (!clockFnd) *clock = clk[best];
1058
1059 return bestStart[best];
1060 }
1061
1062 int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
1063 int firstPhaseShift = 0;
1064 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
1065 }
1066
1067 //by marshmellow
1068 //detect psk clock by reading each phase shift
1069 // a phase shift is determined by measuring the sample length of each wave
1070 int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
1071 uint8_t clk[] = {255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
1072 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1073
1074 //if we already have a valid clock quit
1075 size_t i=1;
1076 for (; i < 8; ++i)
1077 if (clk[i] == clock) return clock;
1078
1079 if (size < 160+20) return 0;
1080 // size must be larger than 20 here, and 160 later on.
1081 if (size < loopCnt) loopCnt = size-20;
1082
1083 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
1084 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
1085 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
1086 uint16_t bestErr[] = {1000,1000,1000,1000,1000,1000,1000,1000,1000};
1087 uint16_t peaksdet[] = {0,0,0,0,0,0,0,0,0};
1088 fc = countFC(dest, size, 0);
1089 if (fc!=2 && fc!=4 && fc!=8) return -1;
1090 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
1091
1092 //find first full wave
1093 for (i=160; i < loopCnt; i++){
1094 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1095 if (waveStart == 0) {
1096 waveStart = i+1;
1097 //prnt("DEBUG: waveStart: %d",waveStart);
1098 } else {
1099 waveEnd = i+1;
1100 //prnt("DEBUG: waveEnd: %d",waveEnd);
1101 waveLenCnt = waveEnd-waveStart;
1102 if (waveLenCnt > fc){
1103 firstFullWave = waveStart;
1104 fullWaveLen=waveLenCnt;
1105 break;
1106 }
1107 waveStart=0;
1108 }
1109 }
1110 }
1111 *firstPhaseShift = firstFullWave;
1112 if (g_debugMode == 2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1113
1114 //test each valid clock from greatest to smallest to see which lines up
1115 for (clkCnt=7; clkCnt >= 1 ; clkCnt--){
1116 lastClkBit = firstFullWave; //set end of wave as clock align
1117 waveStart = 0;
1118 errCnt=0;
1119 peakcnt=0;
1120 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
1121
1122 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1123 //top edge of wave = start of new wave
1124 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1125 if (waveStart == 0) {
1126 waveStart = i+1;
1127 waveLenCnt=0;
1128 } else { //waveEnd
1129 waveEnd = i+1;
1130 waveLenCnt = waveEnd-waveStart;
1131 if (waveLenCnt > fc){
1132 //if this wave is a phase shift
1133 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);
1134 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1135 peakcnt++;
1136 lastClkBit+=clk[clkCnt];
1137 } else if (i<lastClkBit+8){
1138 //noise after a phase shift - ignore
1139 } else { //phase shift before supposed to based on clock
1140 errCnt++;
1141 }
1142 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1143 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1144 }
1145 waveStart=i+1;
1146 }
1147 }
1148 }
1149 if (errCnt == 0) return clk[clkCnt];
1150 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt] = errCnt;
1151 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt] = peakcnt;
1152 }
1153 //all tested with errors
1154 //return the highest clk with the most peaks found
1155 uint8_t best = 7;
1156 for (i=7; i >= 1; i--){
1157 if (peaksdet[i] > peaksdet[best])
1158 best = i;
1159
1160 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
1161 }
1162 return clk[best];
1163 }
1164
1165 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1166 //find shortest transition from high to low
1167 size_t i = 0;
1168 size_t transition1 = 0;
1169 int lowestTransition = 255;
1170 bool lastWasHigh = false;
1171
1172 //find first valid beginning of a high or low wave
1173 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1174 ++i;
1175 while ((dest[i] < peak && dest[i] > low) && (i < size))
1176 ++i;
1177 lastWasHigh = (dest[i] >= peak);
1178
1179 if (i==size) return 0;
1180 transition1 = i;
1181
1182 for (;i < size; i++) {
1183 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1184 lastWasHigh = (dest[i] >= peak);
1185 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1186 transition1 = i;
1187 }
1188 }
1189 if (lowestTransition == 255) lowestTransition = 0;
1190 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
1191 return lowestTransition;
1192 }
1193
1194 int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
1195 int bestStart = 0;
1196 return DetectNRZClock_ext(dest, size, clock, &bestStart);
1197 }
1198
1199 //by marshmellow
1200 //detect nrz clock by reading #peaks vs no peaks(or errors)
1201 int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, int *clockStartIdx) {
1202 size_t i = 0;
1203 uint8_t clk[] = {8,16,32,40,50,64,100,128,255};
1204 size_t loopCnt = 4096; //don't need to loop through entire array...
1205
1206 //if we already have a valid clock quit
1207 for (; i < 8; ++i)
1208 if (clk[i] == clock) return clock;
1209
1210 if (size < 20) return 0;
1211 // size must be larger than 20 here
1212 if (size < loopCnt) loopCnt = size-20;
1213
1214 //get high and low peak
1215 int peak, low;
1216 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
1217
1218 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
1219 size_t ii;
1220 uint8_t clkCnt;
1221 uint8_t tol = 0;
1222 uint16_t smplCnt = 0;
1223 int16_t peakcnt = 0;
1224 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1225 uint16_t maxPeak = 255;
1226 bool firstpeak = false;
1227 //test for large clipped waves
1228 for (i=0; i<loopCnt; i++){
1229 if (dest[i] >= peak || dest[i] <= low){
1230 if (!firstpeak) continue;
1231 smplCnt++;
1232 } else {
1233 firstpeak = true;
1234 if (smplCnt > 6 ){
1235 if (maxPeak > smplCnt){
1236 maxPeak = smplCnt;
1237 //prnt("maxPk: %d",maxPeak);
1238 }
1239 peakcnt++;
1240 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1241 smplCnt = 0;
1242 }
1243 }
1244 }
1245 bool errBitHigh = 0;
1246 bool bitHigh = 0;
1247 uint8_t ignoreCnt = 0;
1248 uint8_t ignoreWindow = 4;
1249 bool lastPeakHigh = 0;
1250 int lastBit = 0;
1251 int bestStart[] = {0,0,0,0,0,0,0,0,0};
1252 peakcnt = 0;
1253 //test each valid clock from smallest to greatest to see which lines up
1254 for(clkCnt=0; clkCnt < 8; ++clkCnt){
1255 //ignore clocks smaller than smallest peak
1256 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
1257 //try lining up the peaks by moving starting point (try first 256)
1258 for (ii=20; ii < loopCnt; ++ii){
1259 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1260 peakcnt=0;
1261 bitHigh = false;
1262 ignoreCnt = 0;
1263 lastBit = ii-clk[clkCnt];
1264 //loop through to see if this start location works
1265 for (i = ii; i < size-20; ++i) {
1266 //if we are at a clock bit
1267 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1268 //test high/low
1269 if (dest[i] >= peak || dest[i] <= low) {
1270 //if same peak don't count it
1271 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1272 peakcnt++;
1273 }
1274 lastPeakHigh = (dest[i] >= peak);
1275 bitHigh = true;
1276 errBitHigh = false;
1277 ignoreCnt = ignoreWindow;
1278 lastBit += clk[clkCnt];
1279 } else if (i == lastBit + clk[clkCnt] + tol) {
1280 lastBit += clk[clkCnt];
1281 }
1282 //else if not a clock bit and no peaks
1283 } else if (dest[i] < peak && dest[i] > low){
1284 if (ignoreCnt == 0){
1285 bitHigh=false;
1286 if (errBitHigh==true)
1287 peakcnt--;
1288 errBitHigh=false;
1289 } else {
1290 ignoreCnt--;
1291 }
1292 // else if not a clock bit but we have a peak
1293 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1294 //error bar found no clock...
1295 errBitHigh=true;
1296 }
1297 }
1298 if (peakcnt > peaksdet[clkCnt]) {
1299 bestStart[clkCnt]=ii;
1300 peaksdet[clkCnt] = peakcnt;
1301 }
1302 }
1303 }
1304 }
1305
1306 uint8_t best = 0;
1307 for (int m = 7; m > 0; m--){
1308 if ((peaksdet[m] >= (peaksdet[best]-1)) && (peaksdet[m] <= peaksdet[best]+1) && lowestTransition) {
1309 if (clk[m] > (lowestTransition - (clk[m]/8)) && clk[m] < (lowestTransition + (clk[m]/8))) {
1310 best = m;
1311 }
1312 } else if (peaksdet[m] > peaksdet[best]){
1313 best = m;
1314 }
1315 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);
1316 }
1317 *clockStartIdx = bestStart[best];
1318 return clk[best];
1319 }
1320
1321 // by marshmellow
1322 // convert psk1 demod to psk2 demod
1323 // only transition waves are 1s
1324 void psk1TOpsk2(uint8_t *bits, size_t size) {
1325 uint8_t lastBit = bits[0];
1326 for (size_t i = 1; i < size; i++){
1327 //ignore errors
1328 if (bits[i] == 7) continue;
1329
1330 if (lastBit != bits[i]){
1331 lastBit = bits[i];
1332 bits[i] = 1;
1333 } else {
1334 bits[i] = 0;
1335 }
1336 }
1337 }
1338
1339 // by marshmellow
1340 // convert psk2 demod to psk1 demod
1341 // from only transition waves are 1s to phase shifts change bit
1342 void psk2TOpsk1(uint8_t *bits, size_t size) {
1343 uint8_t phase = 0;
1344 for (size_t i = 0; i < size; i++){
1345 if (bits[i] == 1){
1346 phase ^= 1;
1347 }
1348 bits[i] = phase;
1349 }
1350 }
1351
1352 // redesigned by marshmellow adjusted from existing decode functions
1353 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1354 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1355 {
1356 //26 bit 40134 format (don't know other formats)
1357 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};
1358 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};
1359 size_t startidx = 0;
1360 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1361 // if didn't find preamble try again inverting
1362 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1363 *invert ^= 1;
1364 }
1365 if (*size != 64 && *size != 224) return -2;
1366 if (*invert==1)
1367 for (size_t i = startidx; i < *size; i++)
1368 bitStream[i] ^= 1;
1369
1370 return (int) startidx;
1371 }
1372
1373 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1374 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1375 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
1376 if (justNoise(dest, *size)) return -1;
1377 *clk = DetectNRZClock(dest, *size, *clk);
1378 if (*clk==0) return -2;
1379 size_t i, gLen = 4096;
1380 if (gLen>*size) gLen = *size-20;
1381 int high, low;
1382 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1383
1384 uint8_t bit=0;
1385 //convert wave samples to 1's and 0's
1386 for(i=20; i < *size-20; i++){
1387 if (dest[i] >= high) bit = 1;
1388 if (dest[i] <= low) bit = 0;
1389 dest[i] = bit;
1390 }
1391 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1392 size_t lastBit = 0;
1393 size_t numBits = 0;
1394 for(i=21; i < *size-20; i++) {
1395 //if transition detected or large number of same bits - store the passed bits
1396 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1397 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1398 numBits += (i - lastBit + (*clk/4)) / *clk;
1399 lastBit = i-1;
1400 }
1401 }
1402 *size = numBits;
1403 return 0;
1404 }
1405
1406 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
1407 int firstClockEdge = 0;
1408 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
1409 }
1410
1411 //by marshmellow
1412 //detects the bit clock for FSK given the high and low Field Clocks
1413 uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
1414 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1415 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1416 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1417 uint8_t rfLensFnd = 0;
1418 uint8_t lastFCcnt = 0;
1419 uint16_t fcCounter = 0;
1420 uint16_t rfCounter = 0;
1421 uint8_t firstBitFnd = 0;
1422 size_t i;
1423 if (size == 0) return 0;
1424
1425 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1426 rfLensFnd=0;
1427 fcCounter=0;
1428 rfCounter=0;
1429 firstBitFnd=0;
1430 //prnt("DEBUG: fcTol: %d",fcTol);
1431 // prime i to first peak / up transition
1432 for (i = 160; i < size-20; i++)
1433 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1434 break;
1435
1436 for (; i < size-20; i++){
1437 fcCounter++;
1438 rfCounter++;
1439
1440 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1441 continue;
1442 // else new peak
1443 // if we got less than the small fc + tolerance then set it to the small fc
1444 // if it is inbetween set it to the last counter
1445 if (fcCounter < fcHigh && fcCounter > fcLow)
1446 fcCounter = lastFCcnt;
1447 else if (fcCounter < fcLow+fcTol)
1448 fcCounter = fcLow;
1449 else //set it to the large fc
1450 fcCounter = fcHigh;
1451
1452 //look for bit clock (rf/xx)
1453 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1454 //not the same size as the last wave - start of new bit sequence
1455 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1456 for (int ii=0; ii<15; ii++){
1457 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
1458 rfCnts[ii]++;
1459 rfCounter = 0;
1460 break;
1461 }
1462 }
1463 if (rfCounter > 0 && rfLensFnd < 15){
1464 //prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1465 rfCnts[rfLensFnd]++;
1466 rfLens[rfLensFnd++] = rfCounter;
1467 }
1468 } else {
1469 *firstClockEdge = i;
1470 firstBitFnd++;
1471 }
1472 rfCounter=0;
1473 lastFCcnt=fcCounter;
1474 }
1475 fcCounter=0;
1476 }
1477 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1478
1479 for (i=0; i<15; i++){
1480 //get highest 2 RF values (might need to get more values to compare or compare all?)
1481 if (rfCnts[i]>rfCnts[rfHighest]){
1482 rfHighest3=rfHighest2;
1483 rfHighest2=rfHighest;
1484 rfHighest=i;
1485 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1486 rfHighest3=rfHighest2;
1487 rfHighest2=i;
1488 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1489 rfHighest3=i;
1490 }
1491 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
1492 }
1493 // set allowed clock remainder tolerance to be 1 large field clock length+1
1494 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1495 uint8_t tol1 = fcHigh+1;
1496
1497 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
1498
1499 // loop to find the highest clock that has a remainder less than the tolerance
1500 // compare samples counted divided by
1501 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1502 int ii=7;
1503 for (; ii>=2; ii--){
1504 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1505 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1506 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
1507 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
1508 break;
1509 }
1510 }
1511 }
1512 }
1513
1514 if (ii<2) return 0; // oops we went too far
1515
1516 return clk[ii];
1517 }
1518
1519 //by marshmellow
1520 //countFC is to detect the field clock lengths.
1521 //counts and returns the 2 most common wave lengths
1522 //mainly used for FSK field clock detection
1523 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
1524 {
1525 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1526 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1527 uint8_t fcLensFnd = 0;
1528 uint8_t lastFCcnt = 0;
1529 uint8_t fcCounter = 0;
1530 size_t i;
1531 if (size < 180) return 0;
1532
1533 // prime i to first up transition
1534 for (i = 160; i < size-20; i++)
1535 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1536 break;
1537
1538 for (; i < size-20; i++){
1539 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1540 // new up transition
1541 fcCounter++;
1542 if (fskAdj){
1543 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1544 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1545 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1546 if ((fcCounter==9) || fcCounter==4) fcCounter++;
1547 // save last field clock count (fc/xx)
1548 lastFCcnt = fcCounter;
1549 }
1550 // find which fcLens to save it to:
1551 for (int ii=0; ii<15; ii++){
1552 if (fcLens[ii]==fcCounter){
1553 fcCnts[ii]++;
1554 fcCounter=0;
1555 break;
1556 }
1557 }
1558 if (fcCounter>0 && fcLensFnd<15){
1559 //add new fc length
1560 fcCnts[fcLensFnd]++;
1561 fcLens[fcLensFnd++]=fcCounter;
1562 }
1563 fcCounter=0;
1564 } else {
1565 // count sample
1566 fcCounter++;
1567 }
1568 }
1569
1570 uint8_t best1=14, best2=14, best3=14;
1571 uint16_t maxCnt1=0;
1572 // go through fclens and find which ones are bigest 2
1573 for (i=0; i<15; i++){
1574 // get the 3 best FC values
1575 if (fcCnts[i]>maxCnt1) {
1576 best3=best2;
1577 best2=best1;
1578 maxCnt1=fcCnts[i];
1579 best1=i;
1580 } else if(fcCnts[i]>fcCnts[best2]){
1581 best3=best2;
1582 best2=i;
1583 } else if(fcCnts[i]>fcCnts[best3]){
1584 best3=i;
1585 }
1586 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]);
1587 }
1588 if (fcLens[best1]==0) return 0;
1589 uint8_t fcH=0, fcL=0;
1590 if (fcLens[best1]>fcLens[best2]){
1591 fcH=fcLens[best1];
1592 fcL=fcLens[best2];
1593 } else{
1594 fcH=fcLens[best2];
1595 fcL=fcLens[best1];
1596 }
1597 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1598 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]);
1599 return 0; //lots of waves not psk or fsk
1600 }
1601 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1602
1603 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
1604 if (fskAdj) return fcs;
1605 return fcLens[best1];
1606 }
1607
1608 //by marshmellow - demodulate PSK1 wave
1609 //uses wave lengths (# Samples)
1610 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1611 {
1612 if (size == 0) return -1;
1613 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1614 if (*size<loopCnt) loopCnt = *size;
1615
1616 size_t numBits=0;
1617 uint8_t curPhase = *invert;
1618 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1619 uint16_t fc=0, fullWaveLen=0, tol=1;
1620 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1621 fc = countFC(dest, *size, 1);
1622 uint8_t fc2 = fc >> 8;
1623 if (fc2 == 10) return -1; //fsk found - quit
1624 fc = fc & 0xFF;
1625 if (fc!=2 && fc!=4 && fc!=8) return -1;
1626 //prnt("DEBUG: FC: %d",fc);
1627 *clock = DetectPSKClock(dest, *size, *clock);
1628 if (*clock == 0) return -1;
1629
1630 //find start of modulating data in trace
1631 uint8_t threshold_value = 123; //-5
1632 i = findModStart(dest, *size, threshold_value, fc);
1633
1634 //find first phase shift
1635 int avgWaveVal=0, lastAvgWaveVal=0;
1636 waveStart = i;
1637 for (; i<loopCnt; i++){
1638 // find peak
1639 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1640 waveEnd = i+1;
1641 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1642 waveLenCnt = waveEnd-waveStart;
1643 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1644 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1645 firstFullWave = waveStart;
1646 fullWaveLen=waveLenCnt;
1647 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1648 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
1649 break;
1650 }
1651 waveStart = i+1;
1652 avgWaveVal = 0;
1653 }
1654 avgWaveVal += dest[i+2];
1655 }
1656 if (firstFullWave == 0) {
1657 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1658 // so skip a little to ensure we are past any Start Signal
1659 firstFullWave = 160;
1660 memset(dest, curPhase, firstFullWave / *clock);
1661 } else {
1662 memset(dest, curPhase^1, firstFullWave / *clock);
1663 }
1664 //advance bits
1665 numBits += (firstFullWave / *clock);
1666 //set start of wave as clock align
1667 lastClkBit = firstFullWave;
1668 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
1669 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1670 waveStart = 0;
1671 dest[numBits++] = curPhase; //set first read bit
1672 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1673 //top edge of wave = start of new wave
1674 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1675 if (waveStart == 0) {
1676 waveStart = i+1;
1677 waveLenCnt = 0;
1678 avgWaveVal = dest[i+1];
1679 } else { //waveEnd
1680 waveEnd = i+1;
1681 waveLenCnt = waveEnd-waveStart;
1682 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1683 if (waveLenCnt > fc){
1684 //prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1685 //this wave is a phase shift
1686 //prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1687 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1688 curPhase ^= 1;
1689 dest[numBits++] = curPhase;
1690 lastClkBit += *clock;
1691 } else if (i < lastClkBit+10+fc){
1692 //noise after a phase shift - ignore
1693 } else { //phase shift before supposed to based on clock
1694 errCnt++;
1695 dest[numBits++] = 7;
1696 }
1697 } else if (i+1 > lastClkBit + *clock + tol + fc){
1698 lastClkBit += *clock; //no phase shift but clock bit
1699 dest[numBits++] = curPhase;
1700 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1701 errCnt2++;
1702 if(errCnt2 > 101) return errCnt2;
1703 }
1704 avgWaveVal = 0;
1705 waveStart = i+1;
1706 }
1707 }
1708 avgWaveVal += dest[i+1];
1709 }
1710 *size = numBits;
1711 return errCnt;
1712 }
1713
1714 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1715 size_t ststart = 0, stend = 0;
1716 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1717 }
1718
1719 //by marshmellow
1720 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1721 bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
1722 size_t bufsize = *size;
1723 //need to loop through all samples and identify our clock, look for the ST pattern
1724 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1725 int clk = 0;
1726 int tol = 0;
1727 int i, j, skip, start, end, low, high, minClk, waveStart;
1728 bool complete = false;
1729 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1730 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
1731 size_t testsize = (bufsize < 512) ? bufsize : 512;
1732 int phaseoff = 0;
1733 high = low = 128;
1734 memset(tmpbuff, 0, sizeof(tmpbuff));
1735 memset(waveLen, 0, sizeof(waveLen));
1736
1737
1738 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1739 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1740 return false; //just noise
1741 }
1742 i = 0;
1743 j = 0;
1744 minClk = 255;
1745 // get to first full low to prime loop and skip incomplete first pulse
1746 while ((buffer[i] < high) && (i < bufsize))
1747 ++i;
1748 while ((buffer[i] > low) && (i < bufsize))
1749 ++i;
1750 skip = i;
1751
1752 // populate tmpbuff buffer with pulse lengths
1753 while (i < bufsize) {
1754 // measure from low to low
1755 while ((buffer[i] > low) && (i < bufsize))
1756 ++i;
1757 start= i;
1758 while ((buffer[i] < high) && (i < bufsize))
1759 ++i;
1760 //first high point for this wave
1761 waveStart = i;
1762 while ((buffer[i] > low) && (i < bufsize))
1763 ++i;
1764 if (j >= (bufsize/32)) {
1765 break;
1766 }
1767 waveLen[j] = i - waveStart; //first high to first low
1768 tmpbuff[j++] = i - start;
1769 if (i-start < minClk && i < bufsize) {
1770 minClk = i - start;
1771 }
1772 }
1773 // set clock - might be able to get this externally and remove this work...
1774 if (!clk) {
1775 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1776 tol = fndClk[clkCnt]/8;
1777 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1778 clk=fndClk[clkCnt];
1779 break;
1780 }
1781 }
1782 // clock not found - ERROR
1783 if (!clk) {
1784 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1785 return false;
1786 }
1787 } else tol = clk/8;
1788
1789 *foundclock = clk;
1790
1791 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1792 start = -1;
1793 for (i = 0; i < j - 4; ++i) {
1794 skip += tmpbuff[i];
1795 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1796 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
1797 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
1798 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1799 start = i + 3;
1800 break;
1801 }
1802 }
1803 }
1804 }
1805 }
1806 // first ST not found - ERROR
1807 if (start < 0) {
1808 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1809 return false;
1810 } else {
1811 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
1812 }
1813 if (waveLen[i+2] > clk*1+tol)
1814 phaseoff = 0;
1815 else
1816 phaseoff = clk/2;
1817
1818 // skip over the remainder of ST
1819 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1820
1821 // now do it again to find the end
1822 end = skip;
1823 for (i += 3; i < j - 4; ++i) {
1824 end += tmpbuff[i];
1825 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1826 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
1827 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
1828 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1829 complete = true;
1830 break;
1831 }
1832 }
1833 }
1834 }
1835 }
1836 end -= phaseoff;
1837 //didn't find second ST - ERROR
1838 if (!complete) {
1839 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1840 return false;
1841 }
1842 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);
1843 //now begin to trim out ST so we can use normal demod cmds
1844 start = skip;
1845 size_t datalen = end - start;
1846 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1847 if ( clk - (datalen % clk) <= clk/8) {
1848 // padd the amount off - could be problematic... but shouldn't happen often
1849 datalen += clk - (datalen % clk);
1850 } else if ( (datalen % clk) <= clk/8 ) {
1851 // padd the amount off - could be problematic... but shouldn't happen often
1852 datalen -= datalen % clk;
1853 } else {
1854 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1855 return false;
1856 }
1857 // if datalen is less than one t55xx block - ERROR
1858 if (datalen/clk < 8*4) {
1859 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1860 return false;
1861 }
1862 size_t dataloc = start;
1863 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1864 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1865 for ( i=0; i <= (clk/8); ++i ) {
1866 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1867 dataloc -= i;
1868 break;
1869 }
1870 }
1871 }
1872
1873 size_t newloc = 0;
1874 i=0;
1875 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1876 bool firstrun = true;
1877 // warning - overwriting buffer given with raw wave data with ST removed...
1878 while ( dataloc < bufsize-(clk/2) ) {
1879 //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)
1880 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1881 for(i=0; i < clk/2-tol; ++i) {
1882 buffer[dataloc+i] = high+5;
1883 }
1884 } //test for single sample outlier (high between two lows) in the case of very strong waves
1885 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1886 buffer[dataloc] = buffer[dataloc+2];
1887 buffer[dataloc+1] = buffer[dataloc+2];
1888 }
1889 if (firstrun) {
1890 *stend = dataloc;
1891 *ststart = dataloc-(clk*4);
1892 firstrun=false;
1893 }
1894 for (i=0; i<datalen; ++i) {
1895 if (i+newloc < bufsize) {
1896 if (i+newloc < dataloc)
1897 buffer[i+newloc] = buffer[dataloc];
1898
1899 dataloc++;
1900 }
1901 }
1902 newloc += i;
1903 //skip next ST - we just assume it will be there from now on...
1904 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1905 dataloc += clk*4;
1906 }
1907 *size = newloc;
1908 return true;
1909 }
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