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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
13void 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
27uint8_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
37int 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
55uint8_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)
68size_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
98size_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
124uint32_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
135uint32_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)
146bool 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
153bool 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.
178size_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
206uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
207{
208 // sanity check
209 if (BitStream[1] > 1) return 0;
210
211 uint8_t fmtlen;
212 *startIdx = 0;
213
214 // preamble 0111111111
215 // include 0 in front to help get start pos
216 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
217 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
218 return 0;
219 if (*size < 64) return 0;
220
221 fmtlen = (*size == 110) ? 22 : 10;
222
223 //skip last 4bit parity row for simplicity
224 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);
225
226 switch (*size) {
227 case 40: {
228 // std em410x format
229 *hi = 0;
230 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
231 break;
232 }
233 case 88: {
234 // long em format
235 *hi = (bytebits_to_byte(BitStream, 24));
236 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
237 break;
238 }
239 default: return 0;
240
241 }
242 return 1;
243}
244
245//by marshmellow
246//demodulates strong heavily clipped samples
247int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
248{
249 size_t bitCnt=0, smplCnt=0, errCnt=0;
250 uint8_t waveHigh = 0;
251 for (size_t i=0; i < *size; i++){
252 if (BinStream[i] >= high && waveHigh){
253 smplCnt++;
254 } else if (BinStream[i] <= low && !waveHigh){
255 smplCnt++;
256 } else { //transition
257 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
258
259 if (smplCnt > clk-(clk/4)-1) { //full clock
260 if (smplCnt > clk + (clk/4)+1) { //too many samples
261 errCnt++;
262 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
263 BinStream[bitCnt++] = 7;
264 } else if (waveHigh) {
265 BinStream[bitCnt++] = invert;
266 BinStream[bitCnt++] = invert;
267 } else if (!waveHigh) {
268 BinStream[bitCnt++] = invert ^ 1;
269 BinStream[bitCnt++] = invert ^ 1;
270 }
271 waveHigh ^= 1;
272 smplCnt = 0;
273 } else if (smplCnt > (clk/2) - (clk/4)-1) {
274 if (waveHigh) {
275 BinStream[bitCnt++] = invert;
276 } else if (!waveHigh) {
277 BinStream[bitCnt++] = invert ^ 1;
278 }
279 waveHigh ^= 1;
280 smplCnt = 0;
281 } else if (!bitCnt) {
282 //first bit
283 waveHigh = (BinStream[i] >= high);
284 smplCnt = 1;
285 } else {
286 smplCnt++;
287 //transition bit oops
288 }
289 } else { //haven't hit new high or new low yet
290 smplCnt++;
291 }
292 }
293 }
294 *size = bitCnt;
295 return errCnt;
296}
297
298//by marshmellow
299void askAmp(uint8_t *BitStream, size_t size)
300{
301 uint8_t last = 128;
302 for(size_t i = 1; i < size; ++i){
303 if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
304 last = 255;
305 else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
306 last = 0;
307
308 BitStream[i] = last;
309 }
310}
311
312//by marshmellow
313//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
314int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
315{
316 if (*size==0) return -1;
317 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
318
319 if (*clk==0 || start < 0) return -3;
320 if (*invert != 1) *invert = 0;
321 if (amp==1) askAmp(BinStream, *size);
322 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
323
324 uint8_t initLoopMax = 255;
325 if (initLoopMax > *size) initLoopMax = *size;
326 // Detect high and lows
327 //25% clip in case highs and lows aren't clipped [marshmellow]
328 int high, low;
329 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
330 return -2; //just noise
331
332 size_t errCnt = 0;
333 // if clean clipped waves detected run alternate demod
334 if (DetectCleanAskWave(BinStream, *size, high, low)) {
335 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
336 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
337 if (askType) //askman
338 return manrawdecode(BinStream, size, 0);
339 //askraw
340 return errCnt;
341 }
342 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
343
344 int lastBit; //set first clock check - can go negative
345 size_t i, bitnum = 0; //output counter
346 uint8_t midBit = 0;
347 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
348 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
349 size_t MaxBits = 3072; //max bits to collect
350 lastBit = start - *clk;
351
352 for (i = start; i < *size; ++i) {
353 if (i-lastBit >= *clk-tol){
354 if (BinStream[i] >= high) {
355 BinStream[bitnum++] = *invert;
356 } else if (BinStream[i] <= low) {
357 BinStream[bitnum++] = *invert ^ 1;
358 } else if (i-lastBit >= *clk+tol) {
359 if (bitnum > 0) {
360 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
361 BinStream[bitnum++]=7;
362 errCnt++;
363 }
364 } else { //in tolerance - looking for peak
365 continue;
366 }
367 midBit = 0;
368 lastBit += *clk;
369 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
370 if (BinStream[i] >= high) {
371 BinStream[bitnum++] = *invert;
372 } else if (BinStream[i] <= low) {
373 BinStream[bitnum++] = *invert ^ 1;
374 } else if (i-lastBit >= *clk/2+tol) {
375 BinStream[bitnum] = BinStream[bitnum-1];
376 bitnum++;
377 } else { //in tolerance - looking for peak
378 continue;
379 }
380 midBit = 1;
381 }
382 if (bitnum >= MaxBits) break;
383 }
384 *size = bitnum;
385 return errCnt;
386}
387//by marshmellow
388//take 10 and 01 and manchester decode
389//run through 2 times and take least errCnt
390int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert){
391 int errCnt = 0, bestErr = 1000;
392 uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;
393 size_t i, k;
394 if (*size < 16) return -1;
395 //find correct start position [alignment]
396 for (k=0; k < 2; ++k){
397 for (i=k; i<*size-3; i += 2)
398 if (BitStream[i] == BitStream[i+1])
399 errCnt++;
400
401 if (bestErr > errCnt){
402 bestErr = errCnt;
403 bestRun = k;
404 }
405 errCnt=0;
406 }
407 //decode
408 for (i=bestRun; i < *size-3; i += 2){
409 if (BitStream[i] == 1 && (BitStream[i+1] == 0)){
410 BitStream[bitnum++] = invert;
411 } else if ((BitStream[i] == 0) && BitStream[i+1] == 1){
412 BitStream[bitnum++] = invert^1;
413 } else {
414 BitStream[bitnum++] = 7;
415 }
416 if (bitnum>MaxBits) break;
417 }
418 *size=bitnum;
419 return bestErr;
420}
421
422uint32_t manchesterEncode2Bytes(uint16_t datain) {
423 uint32_t output = 0;
424 uint8_t curBit = 0;
425 for (uint8_t i=0; i<16; i++) {
426 curBit = (datain >> (15-i) & 1);
427 output |= (1<<(((15-i)*2)+curBit));
428 }
429 return output;
430}
431
432//by marshmellow
433//encode binary data into binary manchester
434int ManchesterEncode(uint8_t *BitStream, size_t size)
435{
436 size_t modIdx=20000, i=0;
437 if (size>modIdx) return -1;
438 for (size_t idx=0; idx < size; idx++){
439 BitStream[idx+modIdx++] = BitStream[idx];
440 BitStream[idx+modIdx++] = BitStream[idx]^1;
441 }
442 for (; i<(size*2); i++){
443 BitStream[i] = BitStream[i+20000];
444 }
445 return i;
446}
447
448//by marshmellow
449//take 01 or 10 = 1 and 11 or 00 = 0
450//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
451//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
452int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
453{
454 uint16_t bitnum = 0;
455 uint16_t errCnt = 0;
456 size_t i = offset;
457 uint16_t MaxBits=512;
458 //if not enough samples - error
459 if (*size < 51) return -1;
460 //check for phase change faults - skip one sample if faulty
461 uint8_t offsetA = 1, offsetB = 1;
462 for (; i<48; i+=2){
463 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
464 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
465 }
466 if (!offsetA && offsetB) offset++;
467 for (i=offset; i<*size-3; i+=2){
468 //check for phase error
469 if (BitStream[i+1]==BitStream[i+2]) {
470 BitStream[bitnum++]=7;
471 errCnt++;
472 }
473 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
474 BitStream[bitnum++]=1^invert;
475 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
476 BitStream[bitnum++]=invert;
477 } else {
478 BitStream[bitnum++]=7;
479 errCnt++;
480 }
481 if(bitnum>MaxBits) break;
482 }
483 *size=bitnum;
484 return errCnt;
485}
486
487// by marshmellow
488// demod gProxIIDemod
489// error returns as -x
490// success returns start position in BitStream
491// BitStream must contain previously askrawdemod and biphasedemoded data
492int gProxII_Demod(uint8_t BitStream[], size_t *size)
493{
494 size_t startIdx=0;
495 uint8_t preamble[] = {1,1,1,1,1,0};
496
497 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx))
498 return -3; //preamble not found
499
500 if (*size != 96) return -2; //should have found 96 bits
501
502 //check first 6 spacer bits to verify format
503 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
504 //confirmed proper separator bits found
505 //return start position
506 return (int) startIdx;
507 }
508 return -5; //spacer bits not found - not a valid gproxII
509}
510
511//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
512size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
513{
514 size_t last_transition = 0;
515 size_t idx = 1;
516 if (fchigh==0) fchigh=10;
517 if (fclow==0) fclow=8;
518 //set the threshold close to 0 (graph) or 128 std to avoid static
519 uint8_t threshold_value = 123;
520 size_t preLastSample = 0;
521 size_t LastSample = 0;
522 size_t currSample = 0;
523 if ( size < 1024 ) return 0; // not enough samples
524
525 //find start of modulating data in trace
526 idx = findModStart(dest, size, threshold_value, fchigh);
527
528 // Need to threshold first sample
529 if(dest[idx] < threshold_value) dest[0] = 0;
530 else dest[0] = 1;
531 idx++;
532
533 size_t numBits = 0;
534 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
535 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
536 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
537 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
538 for(; idx < size-20; idx++) {
539 // threshold current value
540
541 if (dest[idx] < threshold_value) dest[idx] = 0;
542 else dest[idx] = 1;
543
544 // Check for 0->1 transition
545 if (dest[idx-1] < dest[idx]) {
546 preLastSample = LastSample;
547 LastSample = currSample;
548 currSample = idx-last_transition;
549 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
550 //do nothing with extra garbage
551 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
552 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
553 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
554 dest[numBits-1]=1;
555 }
556 dest[numBits++]=1;
557
558 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
559 //do nothing with beginning garbage and reset.. should be rare..
560 numBits = 0;
561 } 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)
562 dest[numBits++]=1;
563 } else { //9+ = 10 sample waves (or 6+ = 7)
564 dest[numBits++]=0;
565 }
566 last_transition = idx;
567 }
568 }
569 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
570}
571
572//translate 11111100000 to 10
573//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
574size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
575 uint8_t invert, uint8_t fchigh, uint8_t fclow)
576{
577 uint8_t lastval=dest[0];
578 size_t idx=0;
579 size_t numBits=0;
580 uint32_t n=1;
581 for( idx=1; idx < size; idx++) {
582 n++;
583 if (dest[idx]==lastval) continue; //skip until we hit a transition
584
585 //find out how many bits (n) we collected
586 //if lastval was 1, we have a 1->0 crossing
587 if (dest[idx-1]==1) {
588 n = (n * fclow + rfLen/2) / rfLen;
589 } else {// 0->1 crossing
590 n = (n * fchigh + rfLen/2) / rfLen;
591 }
592 if (n == 0) n = 1;
593
594 //add to our destination the bits we collected
595 memset(dest+numBits, dest[idx-1]^invert , n);
596 numBits += n;
597 n=0;
598 lastval=dest[idx];
599 }//end for
600 // if valid extra bits at the end were all the same frequency - add them in
601 if (n > rfLen/fchigh) {
602 if (dest[idx-2]==1) {
603 n = (n * fclow + rfLen/2) / rfLen;
604 } else {
605 n = (n * fchigh + rfLen/2) / rfLen;
606 }
607 memset(dest+numBits, dest[idx-1]^invert , n);
608 numBits += n;
609 }
610 return numBits;
611}
612
613//by marshmellow (from holiman's base)
614// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
615int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
616{
617 // FSK demodulator
618 size = fsk_wave_demod(dest, size, fchigh, fclow);
619 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
620 return size;
621}
622
623// loop to get raw HID waveform then FSK demodulate the TAG ID from it
624int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
625{
626 if (justNoise(dest, *size)) return -1;
627
628 size_t numStart=0, size2 = *size, startIdx=0;
629 // FSK demodulator
630 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
631 if (*size < 96*2) return -2;
632 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
633 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
634 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
635 return -3; //preamble not found
636
637 numStart = startIdx + sizeof(preamble);
638 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
639 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
640 if (dest[idx] == dest[idx+1]){
641 return -4; //not manchester data
642 }
643 *hi2 = (*hi2<<1)|(*hi>>31);
644 *hi = (*hi<<1)|(*lo>>31);
645 //Then, shift in a 0 or one into low
646 *lo <<= 1;
647 if (dest[idx] && !dest[idx+1]) // 1 0
648 *lo |= 1;
649 else // 0 1
650 *lo |= 0;
651 }
652 return (int)startIdx;
653}
654
655// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
656int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
657{
658 if (justNoise(dest, *size)) return -1;
659
660 size_t numStart=0, size2 = *size, startIdx=0;
661 // FSK demodulator
662 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
663 if (*size < 96) return -2;
664
665 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
666 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
667 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
668 return -3; //preamble not found
669
670 numStart = startIdx + sizeof(preamble);
671 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
672 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
673 if (dest[idx] == dest[idx+1])
674 return -4; //not manchester data
675 *hi2 = (*hi2<<1)|(*hi>>31);
676 *hi = (*hi<<1)|(*lo>>31);
677 //Then, shift in a 0 or one into low
678 if (dest[idx] && !dest[idx+1]) // 1 0
679 *lo=(*lo<<1)|1;
680 else // 0 1
681 *lo=(*lo<<1)|0;
682 }
683 return (int)startIdx;
684}
685
686int IOdemodFSK(uint8_t *dest, size_t size)
687{
688 if (justNoise(dest, size)) return -1;
689 //make sure buffer has data
690 if (size < 66*64) return -2;
691 // FSK demodulator
692 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
693 if (size < 65) return -3; //did we get a good demod?
694 //Index map
695 //0 10 20 30 40 50 60
696 //| | | | | | |
697 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
698 //-----------------------------------------------------------------------------
699 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
700 //
701 //XSF(version)facility:codeone+codetwo
702 //Handle the data
703 size_t startIdx = 0;
704 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
705 if (! preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx))
706 return -4; //preamble not found
707
708 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
709 //confirmed proper separator bits found
710 //return start position
711 return (int) startIdx;
712 }
713 return -5;
714}
715
716// by marshmellow
717// find viking preamble 0xF200 in already demoded data
718int VikingDemod_AM(uint8_t *dest, size_t *size) {
719 //make sure buffer has data
720 if (*size < 64*2) return -2;
721 size_t startIdx = 0;
722 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};
723 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
724 return -4; //preamble not found
725
726 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^
727 bytebits_to_byte(dest+startIdx+8,8) ^
728 bytebits_to_byte(dest+startIdx+16,8) ^
729 bytebits_to_byte(dest+startIdx+24,8) ^
730 bytebits_to_byte(dest+startIdx+32,8) ^
731 bytebits_to_byte(dest+startIdx+40,8) ^
732 bytebits_to_byte(dest+startIdx+48,8) ^
733 bytebits_to_byte(dest+startIdx+56,8);
734 if ( checkCalc != 0xA8 ) return -5;
735 if (*size != 64) return -6;
736 //return start position
737 return (int)startIdx;
738}
739
740// by iceman
741// find Visa2000 preamble in already demoded data
742int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
743 if (*size < 96) return -1; //make sure buffer has data
744 size_t startIdx = 0;
745 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};
746 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
747 return -2; //preamble not found
748 if (*size != 96) return -3; //wrong demoded size
749 //return start position
750 return (int)startIdx;
751}
752// by iceman
753// find Noralsy preamble in already demoded data
754int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
755 if (*size < 96) return -1; //make sure buffer has data
756 size_t startIdx = 0;
757 uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};
758 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
759 return -2; //preamble not found
760 if (*size != 96) return -3; //wrong demoded size
761 //return start position
762 return (int)startIdx;
763}
764// find presco preamble 0x10D in already demoded data
765int PrescoDemod(uint8_t *dest, size_t *size) {
766 if (*size < 128*2) return -1; //make sure buffer has data
767 size_t startIdx = 0;
768 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};
769 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
770 return -2; //preamble not found
771 if (*size != 128) return -3; //wrong demoded size
772 //return start position
773 return (int)startIdx;
774}
775
776// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
777// BitStream must contain previously askrawdemod and biphasedemoded data
778int FDXBdemodBI(uint8_t *dest, size_t *size) {
779 if (*size < 128*2) return -1; //make sure buffer has enough data
780 size_t startIdx = 0;
781 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
782 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
783 return -2; //preamble not found
784 if (*size != 128) return -3; //wrong demoded size
785 //return start position
786 return (int)startIdx;
787}
788
789// ASK/Diphase fc/64 (inverted Biphase)
790// Note: this i s not a demod, this is only a detection
791// the parameter *dest needs to be demoded before call
792// 0xFFFF preamble, 64bits
793int JablotronDemod(uint8_t *dest, size_t *size){
794 if (*size < 64*2) return -1; //make sure buffer has enough data
795 size_t startIdx = 0;
796 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
797 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
798 return -2; //preamble not found
799 if (*size != 64) return -3; // wrong demoded size
800
801 uint8_t checkchksum = 0;
802 for (int i=16; i < 56; i += 8) {
803 checkchksum += bytebits_to_byte(dest+startIdx+i,8);
804 }
805 checkchksum ^= 0x3A;
806 uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
807 if ( checkchksum != crc ) return -5;
808 return (int)startIdx;
809}
810
811// by marshmellow
812// FSK Demod then try to locate an AWID ID
813int AWIDdemodFSK(uint8_t *dest, size_t *size)
814{
815 //make sure buffer has enough data
816 if (*size < 96*50) return -1;
817
818 if (justNoise(dest, *size)) return -2;
819
820 // FSK demodulator
821 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
822 if (*size < 96) return -3; //did we get a good demod?
823
824 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
825 size_t startIdx = 0;
826 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
827 return -4; //preamble not found
828 if (*size != 96) return -5;
829 return (int)startIdx;
830}
831
832// by marshmellow
833// FSK Demod then try to locate a Farpointe Data (pyramid) ID
834int PyramiddemodFSK(uint8_t *dest, size_t *size)
835{
836 //make sure buffer has data
837 if (*size < 128*50) return -5;
838
839 //test samples are not just noise
840 if (justNoise(dest, *size)) return -1;
841
842 // FSK demodulator
843 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
844 if (*size < 128) return -2; //did we get a good demod?
845 size_t startIdx = 0;
846 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};
847 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
848 return -4; //preamble not found
849 if (*size != 128) return -3;
850 return (int)startIdx;
851}
852
853// find nedap preamble in already demoded data
854int NedapDemod(uint8_t *dest, size_t *size) {
855 //make sure buffer has data
856 if (*size < 128) return -3;
857
858 size_t startIdx = 0;
859 //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
860 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
861 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
862 return -4; //preamble not found
863 return (int) startIdx;
864}
865
866// Find IDTEC PSK1, RF Preamble == 0x4944544B, Demodsize 64bits
867// by iceman
868int IdteckDemodPSK(uint8_t *dest, size_t *size) {
869 //make sure buffer has data
870 if (*size < 64*2) return -1;
871 size_t startIdx = 0;
872 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};
873 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
874 return -2; //preamble not found
875 if (*size != 64) return -3; // wrong demoded size
876 return (int) startIdx;
877}
878
879// by marshmellow
880// to detect a wave that has heavily clipped (clean) samples
881uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
882{
883 bool allArePeaks = true;
884 uint16_t cntPeaks=0;
885 size_t loopEnd = 512+160;
886 if (loopEnd > size) loopEnd = size;
887 for (size_t i=160; i<loopEnd; i++){
888 if (dest[i]>low && dest[i]<high)
889 allArePeaks = false;
890 else
891 cntPeaks++;
892 }
893 if (!allArePeaks){
894 if (cntPeaks > 300) return true;
895 }
896 return allArePeaks;
897}
898// by marshmellow
899// to help detect clocks on heavily clipped samples
900// based on count of low to low
901int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
902{
903 uint8_t fndClk[] = {8,16,32,40,50,64,128};
904 size_t startwave;
905 size_t i = 100;
906 size_t minClk = 255;
907 // get to first full low to prime loop and skip incomplete first pulse
908 while ((dest[i] < high) && (i < size))
909 ++i;
910 while ((dest[i] > low) && (i < size))
911 ++i;
912
913 // loop through all samples
914 while (i < size) {
915 // measure from low to low
916 while ((dest[i] > low) && (i < size))
917 ++i;
918 startwave= i;
919 while ((dest[i] < high) && (i < size))
920 ++i;
921 while ((dest[i] > low) && (i < size))
922 ++i;
923 //get minimum measured distance
924 if (i-startwave < minClk && i < size)
925 minClk = i - startwave;
926 }
927 // set clock
928 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
929 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
930 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
931 return fndClk[clkCnt];
932 }
933 return 0;
934}
935
936// by marshmellow
937// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
938// maybe somehow adjust peak trimming value based on samples to fix?
939// return start index of best starting position for that clock and return clock (by reference)
940int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
941{
942 size_t i=1;
943 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
944 uint8_t clkEnd = 9;
945 uint8_t loopCnt = 255; //don't need to loop through entire array...
946 if (size <= loopCnt+60) return -1; //not enough samples
947 size -= 60; //sometimes there is a strange end wave - filter out this....
948 //if we already have a valid clock
949 uint8_t clockFnd=0;
950 for (;i<clkEnd;++i)
951 if (clk[i] == *clock) clockFnd = i;
952 //clock found but continue to find best startpos
953
954 //get high and low peak
955 int peak, low;
956 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
957
958 //test for large clean peaks
959 if (!clockFnd){
960 if (DetectCleanAskWave(dest, size, peak, low)==1){
961 int ans = DetectStrongAskClock(dest, size, peak, low);
962 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
963 for (i=clkEnd-1; i>0; i--){
964 if (clk[i] == ans) {
965 *clock = ans;
966 //clockFnd = i;
967 return 0; // for strong waves i don't use the 'best start position' yet...
968 //break; //clock found but continue to find best startpos [not yet]
969 }
970 }
971 }
972 }
973 uint8_t ii;
974 uint8_t clkCnt, tol = 0;
975 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
976 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
977 size_t errCnt = 0;
978 size_t arrLoc, loopEnd;
979
980 if (clockFnd>0) {
981 clkCnt = clockFnd;
982 clkEnd = clockFnd+1;
983 } else {
984 clkCnt=1;
985 }
986
987 //test each valid clock from smallest to greatest to see which lines up
988 for(; clkCnt < clkEnd; clkCnt++) {
989 if (clk[clkCnt] <= 32) {
990 tol=1;
991 } else {
992 tol=0;
993 }
994 //if no errors allowed - keep start within the first clock
995 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128)
996 loopCnt = clk[clkCnt] * 2;
997
998 bestErr[clkCnt] = 1000;
999
1000 //try lining up the peaks by moving starting point (try first few clocks)
1001 for (ii=0; ii < loopCnt; ii++){
1002 if (dest[ii] < peak && dest[ii] > low) continue;
1003
1004 errCnt = 0;
1005 // now that we have the first one lined up test rest of wave array
1006 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
1007 for (i=0; i < loopEnd; ++i){
1008 arrLoc = ii + (i * clk[clkCnt]);
1009 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
1010 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
1011 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
1012 }else{ //error no peak detected
1013 errCnt++;
1014 }
1015 }
1016 //if we found no errors then we can stop here and a low clock (common clocks)
1017 // this is correct one - return this clock
1018 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
1019 if (errCnt==0 && clkCnt<7) {
1020 if (!clockFnd) *clock = clk[clkCnt];
1021 return ii;
1022 }
1023 //if we found errors see if it is lowest so far and save it as best run
1024 if (errCnt < bestErr[clkCnt]) {
1025 bestErr[clkCnt] = errCnt;
1026 bestStart[clkCnt] = ii;
1027 }
1028 }
1029 }
1030 uint8_t k;
1031 uint8_t best = 0;
1032 for (k=1; k < clkEnd; ++k){
1033 if (bestErr[k] < bestErr[best]){
1034 if (bestErr[k] == 0) bestErr[k]=1;
1035 // current best bit to error ratio vs new bit to error ratio
1036 if ( (size/clk[best])/bestErr[best] < (size/clk[k])/bestErr[k] ){
1037 best = k;
1038 }
1039 }
1040 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]);
1041 }
1042 if (!clockFnd) *clock = clk[best];
1043 return bestStart[best];
1044}
1045
1046//by marshmellow
1047//detect psk clock by reading each phase shift
1048// a phase shift is determined by measuring the sample length of each wave
1049int DetectPSKClock(uint8_t dest[], size_t size, int clock)
1050{
1051 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
1052 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1053 if (size == 0) return 0;
1054 if (size<loopCnt) loopCnt = size-20;
1055
1056 //if we already have a valid clock quit
1057 size_t i=1;
1058 for (; i < 8; ++i)
1059 if (clk[i] == clock) return clock;
1060
1061 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
1062 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
1063 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
1064 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
1065 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
1066 fc = countFC(dest, size, 0);
1067 if (fc!=2 && fc!=4 && fc!=8) return -1;
1068 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
1069
1070 //find first full wave
1071 for (i=160; i<loopCnt; i++){
1072 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1073 if (waveStart == 0) {
1074 waveStart = i+1;
1075 //prnt("DEBUG: waveStart: %d",waveStart);
1076 } else {
1077 waveEnd = i+1;
1078 //prnt("DEBUG: waveEnd: %d",waveEnd);
1079 waveLenCnt = waveEnd-waveStart;
1080 if (waveLenCnt > fc){
1081 firstFullWave = waveStart;
1082 fullWaveLen=waveLenCnt;
1083 break;
1084 }
1085 waveStart=0;
1086 }
1087 }
1088 }
1089 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1090
1091 //test each valid clock from greatest to smallest to see which lines up
1092 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1093 lastClkBit = firstFullWave; //set end of wave as clock align
1094 waveStart = 0;
1095 errCnt=0;
1096 peakcnt=0;
1097 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
1098
1099 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1100 //top edge of wave = start of new wave
1101 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1102 if (waveStart == 0) {
1103 waveStart = i+1;
1104 waveLenCnt=0;
1105 } else { //waveEnd
1106 waveEnd = i+1;
1107 waveLenCnt = waveEnd-waveStart;
1108 if (waveLenCnt > fc){
1109 //if this wave is a phase shift
1110 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);
1111 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1112 peakcnt++;
1113 lastClkBit+=clk[clkCnt];
1114 } else if (i<lastClkBit+8){
1115 //noise after a phase shift - ignore
1116 } else { //phase shift before supposed to based on clock
1117 errCnt++;
1118 }
1119 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1120 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1121 }
1122 waveStart=i+1;
1123 }
1124 }
1125 }
1126 if (errCnt == 0){
1127 return clk[clkCnt];
1128 }
1129 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1130 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1131 }
1132 //all tested with errors
1133 //return the highest clk with the most peaks found
1134 uint8_t best=7;
1135 for (i=7; i>=1; i--){
1136 if (peaksdet[i] > peaksdet[best]) {
1137 best = i;
1138 }
1139 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
1140 }
1141 return clk[best];
1142}
1143
1144int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1145 //find shortest transition from high to low
1146 size_t i = 0;
1147 size_t transition1 = 0;
1148 int lowestTransition = 255;
1149 bool lastWasHigh = false;
1150
1151 //find first valid beginning of a high or low wave
1152 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1153 ++i;
1154 while ((dest[i] < peak && dest[i] > low) && (i < size))
1155 ++i;
1156 lastWasHigh = (dest[i] >= peak);
1157
1158 if (i==size) return 0;
1159 transition1 = i;
1160
1161 for (;i < size; i++) {
1162 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1163 lastWasHigh = (dest[i] >= peak);
1164 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1165 transition1 = i;
1166 }
1167 }
1168 if (lowestTransition == 255) lowestTransition = 0;
1169 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
1170 return lowestTransition;
1171}
1172
1173//by marshmellow
1174//detect nrz clock by reading #peaks vs no peaks(or errors)
1175int DetectNRZClock(uint8_t dest[], size_t size, int clock)
1176{
1177 size_t i=0;
1178 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1179 size_t loopCnt = 4096; //don't need to loop through entire array...
1180 if (size == 0) return 0;
1181 if (size<loopCnt) loopCnt = size-20;
1182 //if we already have a valid clock quit
1183 for (; i < 8; ++i)
1184 if (clk[i] == clock) return clock;
1185
1186 //get high and low peak
1187 int peak, low;
1188 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
1189
1190 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
1191 size_t ii;
1192 uint8_t clkCnt;
1193 uint8_t tol = 0;
1194 uint16_t smplCnt = 0;
1195 int16_t peakcnt = 0;
1196 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1197 uint16_t maxPeak = 255;
1198 bool firstpeak = false;
1199 //test for large clipped waves
1200 for (i=0; i<loopCnt; i++){
1201 if (dest[i] >= peak || dest[i] <= low){
1202 if (!firstpeak) continue;
1203 smplCnt++;
1204 } else {
1205 firstpeak=true;
1206 if (smplCnt > 6 ){
1207 if (maxPeak > smplCnt){
1208 maxPeak = smplCnt;
1209 //prnt("maxPk: %d",maxPeak);
1210 }
1211 peakcnt++;
1212 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1213 smplCnt=0;
1214 }
1215 }
1216 }
1217 bool errBitHigh = 0;
1218 bool bitHigh = 0;
1219 uint8_t ignoreCnt = 0;
1220 uint8_t ignoreWindow = 4;
1221 bool lastPeakHigh = 0;
1222 int lastBit = 0;
1223 peakcnt=0;
1224 //test each valid clock from smallest to greatest to see which lines up
1225 for(clkCnt=0; clkCnt < 8; ++clkCnt){
1226 //ignore clocks smaller than smallest peak
1227 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
1228 //try lining up the peaks by moving starting point (try first 256)
1229 for (ii=20; ii < loopCnt; ++ii){
1230 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1231 peakcnt=0;
1232 bitHigh = false;
1233 ignoreCnt = 0;
1234 lastBit = ii-clk[clkCnt];
1235 //loop through to see if this start location works
1236 for (i = ii; i < size-20; ++i) {
1237 //if we are at a clock bit
1238 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1239 //test high/low
1240 if (dest[i] >= peak || dest[i] <= low) {
1241 //if same peak don't count it
1242 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1243 peakcnt++;
1244 }
1245 lastPeakHigh = (dest[i] >= peak);
1246 bitHigh = true;
1247 errBitHigh = false;
1248 ignoreCnt = ignoreWindow;
1249 lastBit += clk[clkCnt];
1250 } else if (i == lastBit + clk[clkCnt] + tol) {
1251 lastBit += clk[clkCnt];
1252 }
1253 //else if not a clock bit and no peaks
1254 } else if (dest[i] < peak && dest[i] > low){
1255 if (ignoreCnt==0){
1256 bitHigh=false;
1257 if (errBitHigh==true) peakcnt--;
1258 errBitHigh=false;
1259 } else {
1260 ignoreCnt--;
1261 }
1262 // else if not a clock bit but we have a peak
1263 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1264 //error bar found no clock...
1265 errBitHigh=true;
1266 }
1267 }
1268 if(peakcnt>peaksdet[clkCnt]) {
1269 peaksdet[clkCnt]=peakcnt;
1270 }
1271 }
1272 }
1273 }
1274 int iii=7;
1275 uint8_t best=0;
1276 for (iii=7; iii > 0; iii--){
1277 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1278 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
1279 best = iii;
1280 }
1281 } else if (peaksdet[iii] > peaksdet[best]){
1282 best = iii;
1283 }
1284 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);
1285 }
1286
1287 return clk[best];
1288}
1289
1290// by marshmellow
1291// convert psk1 demod to psk2 demod
1292// only transition waves are 1s
1293void psk1TOpsk2(uint8_t *bits, size_t size) {
1294 uint8_t lastBit = bits[0];
1295 for (size_t i = 1; i < size; i++){
1296 //ignore errors
1297 if (bits[i] == 7) continue;
1298
1299 if (lastBit != bits[i]){
1300 lastBit = bits[i];
1301 bits[i] = 1;
1302 } else {
1303 bits[i] = 0;
1304 }
1305 }
1306}
1307
1308// by marshmellow
1309// convert psk2 demod to psk1 demod
1310// from only transition waves are 1s to phase shifts change bit
1311void psk2TOpsk1(uint8_t *bits, size_t size) {
1312 uint8_t phase = 0;
1313 for (size_t i = 0; i < size; i++){
1314 if (bits[i] == 1){
1315 phase ^= 1;
1316 }
1317 bits[i] = phase;
1318 }
1319}
1320
1321// redesigned by marshmellow adjusted from existing decode functions
1322// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1323int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1324{
1325 //26 bit 40134 format (don't know other formats)
1326 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};
1327 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};
1328 size_t startidx = 0;
1329 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1330 // if didn't find preamble try again inverting
1331 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1332 *invert ^= 1;
1333 }
1334 if (*size != 64 && *size != 224) return -2;
1335 if (*invert==1)
1336 for (size_t i = startidx; i < *size; i++)
1337 bitStream[i] ^= 1;
1338
1339 return (int) startidx;
1340}
1341
1342// by marshmellow - demodulate NRZ wave - requires a read with strong signal
1343// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1344int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
1345 if (justNoise(dest, *size)) return -1;
1346 *clk = DetectNRZClock(dest, *size, *clk);
1347 if (*clk==0) return -2;
1348 size_t i, gLen = 4096;
1349 if (gLen>*size) gLen = *size-20;
1350 int high, low;
1351 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1352
1353 uint8_t bit=0;
1354 //convert wave samples to 1's and 0's
1355 for(i=20; i < *size-20; i++){
1356 if (dest[i] >= high) bit = 1;
1357 if (dest[i] <= low) bit = 0;
1358 dest[i] = bit;
1359 }
1360 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1361 size_t lastBit = 0;
1362 size_t numBits = 0;
1363 for(i=21; i < *size-20; i++) {
1364 //if transition detected or large number of same bits - store the passed bits
1365 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1366 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1367 numBits += (i - lastBit + (*clk/4)) / *clk;
1368 lastBit = i-1;
1369 }
1370 }
1371 *size = numBits;
1372 return 0;
1373}
1374
1375//by marshmellow
1376//detects the bit clock for FSK given the high and low Field Clocks
1377uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1378{
1379 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1380 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1381 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1382 uint8_t rfLensFnd = 0;
1383 uint8_t lastFCcnt = 0;
1384 uint16_t fcCounter = 0;
1385 uint16_t rfCounter = 0;
1386 uint8_t firstBitFnd = 0;
1387 size_t i;
1388 if (size == 0) return 0;
1389
1390 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1391 rfLensFnd=0;
1392 fcCounter=0;
1393 rfCounter=0;
1394 firstBitFnd=0;
1395 //prnt("DEBUG: fcTol: %d",fcTol);
1396 // prime i to first peak / up transition
1397 for (i = 160; i < size-20; i++)
1398 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1399 break;
1400
1401 for (; i < size-20; i++){
1402 fcCounter++;
1403 rfCounter++;
1404
1405 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1406 continue;
1407 // else new peak
1408 // if we got less than the small fc + tolerance then set it to the small fc
1409 // if it is inbetween set it to the last counter
1410 if (fcCounter < fcHigh && fcCounter > fcLow)
1411 fcCounter = lastFCcnt;
1412 else if (fcCounter < fcLow+fcTol)
1413 fcCounter = fcLow;
1414 else //set it to the large fc
1415 fcCounter = fcHigh;
1416
1417 //look for bit clock (rf/xx)
1418 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1419 //not the same size as the last wave - start of new bit sequence
1420 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1421 for (int ii=0; ii<15; ii++){
1422 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
1423 rfCnts[ii]++;
1424 rfCounter = 0;
1425 break;
1426 }
1427 }
1428 if (rfCounter > 0 && rfLensFnd < 15){
1429 //prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1430 rfCnts[rfLensFnd]++;
1431 rfLens[rfLensFnd++] = rfCounter;
1432 }
1433 } else {
1434 firstBitFnd++;
1435 }
1436 rfCounter=0;
1437 lastFCcnt=fcCounter;
1438 }
1439 fcCounter=0;
1440 }
1441 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1442
1443 for (i=0; i<15; i++){
1444 //get highest 2 RF values (might need to get more values to compare or compare all?)
1445 if (rfCnts[i]>rfCnts[rfHighest]){
1446 rfHighest3=rfHighest2;
1447 rfHighest2=rfHighest;
1448 rfHighest=i;
1449 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1450 rfHighest3=rfHighest2;
1451 rfHighest2=i;
1452 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1453 rfHighest3=i;
1454 }
1455 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
1456 }
1457 // set allowed clock remainder tolerance to be 1 large field clock length+1
1458 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1459 uint8_t tol1 = fcHigh+1;
1460
1461 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
1462
1463 // loop to find the highest clock that has a remainder less than the tolerance
1464 // compare samples counted divided by
1465 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1466 int ii=7;
1467 for (; ii>=2; ii--){
1468 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1469 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1470 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
1471 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
1472 break;
1473 }
1474 }
1475 }
1476 }
1477
1478 if (ii<2) return 0; // oops we went too far
1479
1480 return clk[ii];
1481}
1482
1483//by marshmellow
1484//countFC is to detect the field clock lengths.
1485//counts and returns the 2 most common wave lengths
1486//mainly used for FSK field clock detection
1487uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
1488{
1489 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1490 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1491 uint8_t fcLensFnd = 0;
1492 uint8_t lastFCcnt = 0;
1493 uint8_t fcCounter = 0;
1494 size_t i;
1495 if (size < 180) return 0;
1496
1497 // prime i to first up transition
1498 for (i = 160; i < size-20; i++)
1499 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1500 break;
1501
1502 for (; i < size-20; i++){
1503 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1504 // new up transition
1505 fcCounter++;
1506 if (fskAdj){
1507 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1508 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1509 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1510 if ((fcCounter==9) || fcCounter==4) fcCounter++;
1511 // save last field clock count (fc/xx)
1512 lastFCcnt = fcCounter;
1513 }
1514 // find which fcLens to save it to:
1515 for (int ii=0; ii<15; ii++){
1516 if (fcLens[ii]==fcCounter){
1517 fcCnts[ii]++;
1518 fcCounter=0;
1519 break;
1520 }
1521 }
1522 if (fcCounter>0 && fcLensFnd<15){
1523 //add new fc length
1524 fcCnts[fcLensFnd]++;
1525 fcLens[fcLensFnd++]=fcCounter;
1526 }
1527 fcCounter=0;
1528 } else {
1529 // count sample
1530 fcCounter++;
1531 }
1532 }
1533
1534 uint8_t best1=14, best2=14, best3=14;
1535 uint16_t maxCnt1=0;
1536 // go through fclens and find which ones are bigest 2
1537 for (i=0; i<15; i++){
1538 // get the 3 best FC values
1539 if (fcCnts[i]>maxCnt1) {
1540 best3=best2;
1541 best2=best1;
1542 maxCnt1=fcCnts[i];
1543 best1=i;
1544 } else if(fcCnts[i]>fcCnts[best2]){
1545 best3=best2;
1546 best2=i;
1547 } else if(fcCnts[i]>fcCnts[best3]){
1548 best3=i;
1549 }
1550 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]);
1551 }
1552 if (fcLens[best1]==0) return 0;
1553 uint8_t fcH=0, fcL=0;
1554 if (fcLens[best1]>fcLens[best2]){
1555 fcH=fcLens[best1];
1556 fcL=fcLens[best2];
1557 } else{
1558 fcH=fcLens[best2];
1559 fcL=fcLens[best1];
1560 }
1561 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1562 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]);
1563 return 0; //lots of waves not psk or fsk
1564 }
1565 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1566
1567 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
1568 if (fskAdj) return fcs;
1569 return fcLens[best1];
1570}
1571
1572//by marshmellow - demodulate PSK1 wave
1573//uses wave lengths (# Samples)
1574int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1575{
1576 if (size == 0) return -1;
1577 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1578 if (*size<loopCnt) loopCnt = *size;
1579
1580 size_t numBits=0;
1581 uint8_t curPhase = *invert;
1582 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1583 uint16_t fc=0, fullWaveLen=0, tol=1;
1584 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1585 fc = countFC(dest, *size, 1);
1586 uint8_t fc2 = fc >> 8;
1587 if (fc2 == 10) return -1; //fsk found - quit
1588 fc = fc & 0xFF;
1589 if (fc!=2 && fc!=4 && fc!=8) return -1;
1590 //prnt("DEBUG: FC: %d",fc);
1591 *clock = DetectPSKClock(dest, *size, *clock);
1592 if (*clock == 0) return -1;
1593
1594 //find start of modulating data in trace
1595 uint8_t threshold_value = 123; //-5
1596 i = findModStart(dest, *size, threshold_value, fc);
1597
1598 //find first phase shift
1599 int avgWaveVal=0, lastAvgWaveVal=0;
1600 waveStart = i;
1601 for (; i<loopCnt; i++){
1602 // find peak
1603 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1604 waveEnd = i+1;
1605 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1606 waveLenCnt = waveEnd-waveStart;
1607 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1608 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1609 firstFullWave = waveStart;
1610 fullWaveLen=waveLenCnt;
1611 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1612 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
1613 break;
1614 }
1615 waveStart = i+1;
1616 avgWaveVal = 0;
1617 }
1618 avgWaveVal += dest[i+2];
1619 }
1620 if (firstFullWave == 0) {
1621 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1622 // so skip a little to ensure we are past any Start Signal
1623 firstFullWave = 160;
1624 memset(dest, curPhase, firstFullWave / *clock);
1625 } else {
1626 memset(dest, curPhase^1, firstFullWave / *clock);
1627 }
1628 //advance bits
1629 numBits += (firstFullWave / *clock);
1630 //set start of wave as clock align
1631 lastClkBit = firstFullWave;
1632 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
1633 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1634 waveStart = 0;
1635 dest[numBits++] = curPhase; //set first read bit
1636 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1637 //top edge of wave = start of new wave
1638 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1639 if (waveStart == 0) {
1640 waveStart = i+1;
1641 waveLenCnt = 0;
1642 avgWaveVal = dest[i+1];
1643 } else { //waveEnd
1644 waveEnd = i+1;
1645 waveLenCnt = waveEnd-waveStart;
1646 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1647 if (waveLenCnt > fc){
1648 //prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1649 //this wave is a phase shift
1650 //prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1651 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1652 curPhase ^= 1;
1653 dest[numBits++] = curPhase;
1654 lastClkBit += *clock;
1655 } else if (i < lastClkBit+10+fc){
1656 //noise after a phase shift - ignore
1657 } else { //phase shift before supposed to based on clock
1658 errCnt++;
1659 dest[numBits++] = 7;
1660 }
1661 } else if (i+1 > lastClkBit + *clock + tol + fc){
1662 lastClkBit += *clock; //no phase shift but clock bit
1663 dest[numBits++] = curPhase;
1664 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1665 errCnt2++;
1666 if(errCnt2 > 101) return errCnt2;
1667 }
1668 avgWaveVal = 0;
1669 waveStart = i+1;
1670 }
1671 }
1672 avgWaveVal += dest[i+1];
1673 }
1674 *size = numBits;
1675 return errCnt;
1676}
1677
1678//by marshmellow
1679//attempt to identify a Sequence Terminator in ASK modulated raw wave
1680bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1681 size_t bufsize = *size;
1682 //need to loop through all samples and identify our clock, look for the ST pattern
1683 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1684 int clk = 0;
1685 int tol = 0;
1686 int i, j, skip, start, end, low, high, minClk, waveStart;
1687 bool complete = false;
1688 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1689 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
1690 size_t testsize = (bufsize < 512) ? bufsize : 512;
1691 int phaseoff = 0;
1692 high = low = 128;
1693 memset(tmpbuff, 0, sizeof(tmpbuff));
1694 memset(waveLen, 0, sizeof(waveLen));
1695
1696
1697 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1698 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1699 return false; //just noise
1700 }
1701 i = 0;
1702 j = 0;
1703 minClk = 255;
1704 // get to first full low to prime loop and skip incomplete first pulse
1705 while ((buffer[i] < high) && (i < bufsize))
1706 ++i;
1707 while ((buffer[i] > low) && (i < bufsize))
1708 ++i;
1709 skip = i;
1710
1711 // populate tmpbuff buffer with pulse lengths
1712 while (i < bufsize) {
1713 // measure from low to low
1714 while ((buffer[i] > low) && (i < bufsize))
1715 ++i;
1716 start= i;
1717 while ((buffer[i] < high) && (i < bufsize))
1718 ++i;
1719 //first high point for this wave
1720 waveStart = i;
1721 while ((buffer[i] > low) && (i < bufsize))
1722 ++i;
1723 if (j >= (bufsize/32)) {
1724 break;
1725 }
1726 waveLen[j] = i - waveStart; //first high to first low
1727 tmpbuff[j++] = i - start;
1728 if (i-start < minClk && i < bufsize) {
1729 minClk = i - start;
1730 }
1731 }
1732 // set clock - might be able to get this externally and remove this work...
1733 if (!clk) {
1734 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1735 tol = fndClk[clkCnt]/8;
1736 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1737 clk=fndClk[clkCnt];
1738 break;
1739 }
1740 }
1741 // clock not found - ERROR
1742 if (!clk) {
1743 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1744 return false;
1745 }
1746 } else tol = clk/8;
1747
1748 *foundclock = clk;
1749
1750 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1751 start = -1;
1752 for (i = 0; i < j - 4; ++i) {
1753 skip += tmpbuff[i];
1754 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1755 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
1756 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
1757 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1758 start = i + 3;
1759 break;
1760 }
1761 }
1762 }
1763 }
1764 }
1765 // first ST not found - ERROR
1766 if (start < 0) {
1767 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1768 return false;
1769 } else {
1770 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
1771 }
1772 if (waveLen[i+2] > clk*1+tol)
1773 phaseoff = 0;
1774 else
1775 phaseoff = clk/2;
1776
1777 // skip over the remainder of ST
1778 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1779
1780 // now do it again to find the end
1781 end = skip;
1782 for (i += 3; i < j - 4; ++i) {
1783 end += tmpbuff[i];
1784 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1785 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
1786 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
1787 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1788 complete = true;
1789 break;
1790 }
1791 }
1792 }
1793 }
1794 }
1795 end -= phaseoff;
1796 //didn't find second ST - ERROR
1797 if (!complete) {
1798 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1799 return false;
1800 }
1801 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);
1802 //now begin to trim out ST so we can use normal demod cmds
1803 start = skip;
1804 size_t datalen = end - start;
1805 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1806 if ( clk - (datalen % clk) <= clk/8) {
1807 // padd the amount off - could be problematic... but shouldn't happen often
1808 datalen += clk - (datalen % clk);
1809 } else if ( (datalen % clk) <= clk/8 ) {
1810 // padd the amount off - could be problematic... but shouldn't happen often
1811 datalen -= datalen % clk;
1812 } else {
1813 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1814 return false;
1815 }
1816 // if datalen is less than one t55xx block - ERROR
1817 if (datalen/clk < 8*4) {
1818 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1819 return false;
1820 }
1821 size_t dataloc = start;
1822 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1823 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1824 for ( i=0; i <= (clk/8); ++i ) {
1825 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1826 dataloc -= i;
1827 break;
1828 }
1829 }
1830 }
1831
1832 size_t newloc = 0;
1833 i=0;
1834 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1835
1836 // warning - overwriting buffer given with raw wave data with ST removed...
1837 while ( dataloc < bufsize-(clk/2) ) {
1838 //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)
1839 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1840 for(i=0; i < clk/2-tol; ++i) {
1841 buffer[dataloc+i] = high+5;
1842 }
1843 }
1844 for (i=0; i<datalen; ++i) {
1845 if (i+newloc < bufsize) {
1846 if (i+newloc < dataloc)
1847 buffer[i+newloc] = buffer[dataloc];
1848
1849 dataloc++;
1850 }
1851 }
1852 newloc += i;
1853 //skip next ST - we just assume it will be there from now on...
1854 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1855 dataloc += clk*4;
1856 }
1857 *size = newloc;
1858 return true;
1859}
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