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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
11 #include <stdlib.h>
12 #include "lfdemod.h"
13 #include <string.h>
14
15 //to allow debug print calls when used not on device
16 void dummy(char *fmt, ...){}
17
18 #ifndef ON_DEVICE
19 #include "ui.h"
20 #include "cmdparser.h"
21 #include "cmddata.h"
22 #define prnt PrintAndLog
23 #else
24 uint8_t g_debugMode=0;
25 #define prnt dummy
26 #endif
27
28 uint8_t justNoise(uint8_t *BitStream, size_t size)
29 {
30 static const uint8_t THRESHOLD = 123;
31 //test samples are not just noise
32 uint8_t justNoise1 = 1;
33 for(size_t idx=0; idx < size && justNoise1 ;idx++){
34 justNoise1 = BitStream[idx] < THRESHOLD;
35 }
36 return justNoise1;
37 }
38
39 //by marshmellow
40 //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
41 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
42 {
43 *high=0;
44 *low=255;
45 // get high and low thresholds
46 for (size_t i=0; i < size; i++){
47 if (BitStream[i] > *high) *high = BitStream[i];
48 if (BitStream[i] < *low) *low = BitStream[i];
49 }
50 if (*high < 123) return -1; // just noise
51 *high = ((*high-128)*fuzzHi + 12800)/100;
52 *low = ((*low-128)*fuzzLo + 12800)/100;
53 return 1;
54 }
55
56 // by marshmellow
57 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
58 // returns 1 if passed
59 uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
60 {
61 uint8_t ans = 0;
62 for (uint8_t i = 0; i < bitLen; i++){
63 ans ^= ((bits >> i) & 1);
64 }
65 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
66 return (ans == pType);
67 }
68
69 // by marshmellow
70 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
71 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
72 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
73 {
74 uint32_t parityWd = 0;
75 size_t j = 0, bitCnt = 0;
76 for (int word = 0; word < (bLen); word+=pLen) {
77 for (int bit=0; bit < pLen; bit++) {
78 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
79 BitStream[j++] = (BitStream[startIdx+word+bit]);
80 }
81 if (word+pLen >= bLen) break;
82
83 j--; // overwrite parity with next data
84 // if parity fails then return 0
85 switch (pType) {
86 case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
87 case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
88 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
89 }
90 bitCnt+=(pLen-1);
91 parityWd = 0;
92 }
93 // if we got here then all the parities passed
94 //return ID start index and size
95 return bitCnt;
96 }
97
98 // by marshmellow
99 // takes a array of binary values, length of bits per parity (includes parity bit),
100 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
101 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
102 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
103 {
104 uint32_t parityWd = 0;
105 size_t j = 0, bitCnt = 0;
106 for (int word = 0; word < sourceLen; word+=pLen-1) {
107 for (int bit=0; bit < pLen-1; bit++){
108 parityWd = (parityWd << 1) | BitSource[word+bit];
109 dest[j++] = (BitSource[word+bit]);
110 }
111 // if parity fails then return 0
112 switch (pType) {
113 case 3: dest[j++]=0; break; // marker bit which should be a 0
114 case 2: dest[j++]=1; break; // marker bit which should be a 1
115 default:
116 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
117 break;
118 }
119 bitCnt += pLen;
120 parityWd = 0;
121 }
122 // if we got here then all the parities passed
123 //return ID start index and size
124 return bitCnt;
125 }
126
127 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
128 {
129 uint32_t num = 0;
130 for(int i = 0 ; i < numbits ; i++)
131 {
132 num = (num << 1) | (*src);
133 src++;
134 }
135 return num;
136 }
137
138 //least significant bit first
139 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
140 {
141 uint32_t num = 0;
142 for(int i = 0 ; i < numbits ; i++)
143 {
144 num = (num << 1) | *(src + (numbits-(i+1)));
145 }
146 return num;
147 }
148
149 //by marshmellow
150 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
151 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
152 {
153 // Sanity check. If preamble length is bigger than bitstream length.
154 if ( *size <= pLen ) return 0;
155
156 uint8_t foundCnt=0;
157 for (int idx=0; idx < *size - pLen; idx++){
158 if (memcmp(BitStream+idx, preamble, pLen) == 0){
159 //first index found
160 foundCnt++;
161 if (foundCnt == 1){
162 *startIdx = idx;
163 }
164 if (foundCnt == 2){
165 *size = idx - *startIdx;
166 return 1;
167 }
168 }
169 }
170 return 0;
171 }
172
173 //by marshmellow
174 //takes 1s and 0s and searches for EM410x format - output EM ID
175 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
176 {
177 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
178 // otherwise could be a void with no arguments
179 //set defaults
180 uint32_t i = 0;
181 if (BitStream[1]>1) return 0; //allow only 1s and 0s
182
183 // 111111111 bit pattern represent start of frame
184 // include 0 in front to help get start pos
185 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
186 uint32_t idx = 0;
187 uint32_t parityBits = 0;
188 uint8_t errChk = 0;
189 uint8_t FmtLen = 10;
190 *startIdx = 0;
191 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
192 if (errChk == 0 || *size < 64) return 0;
193 if (*size > 64) FmtLen = 22;
194 *startIdx += 1; //get rid of 0 from preamble
195 idx = *startIdx + 9;
196 for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
197 parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
198 //check even parity - quit if failed
199 if (parityTest(parityBits, 5, 0) == 0) return 0;
200 //set uint64 with ID from BitStream
201 for (uint8_t ii=0; ii<4; ii++){
202 *hi = (*hi << 1) | (*lo >> 63);
203 *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
204 }
205 }
206 if (errChk != 0) return 1;
207 //skip last 5 bit parity test for simplicity.
208 // *size = 64 | 128;
209 return 0;
210 }
211
212 //by marshmellow
213 //demodulates strong heavily clipped samples
214 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
215 {
216 size_t bitCnt=0, smplCnt=0, errCnt=0;
217 uint8_t waveHigh = 0;
218 for (size_t i=0; i < *size; i++){
219 if (BinStream[i] >= high && waveHigh){
220 smplCnt++;
221 } else if (BinStream[i] <= low && !waveHigh){
222 smplCnt++;
223 } else { //transition
224 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
225 if (smplCnt > clk-(clk/4)-1) { //full clock
226 if (smplCnt > clk + (clk/4)+1) { //too many samples
227 errCnt++;
228 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
229 BinStream[bitCnt++]=7;
230 } else if (waveHigh) {
231 BinStream[bitCnt++] = invert;
232 BinStream[bitCnt++] = invert;
233 } else if (!waveHigh) {
234 BinStream[bitCnt++] = invert ^ 1;
235 BinStream[bitCnt++] = invert ^ 1;
236 }
237 waveHigh ^= 1;
238 smplCnt = 0;
239 } else if (smplCnt > (clk/2) - (clk/4)-1) {
240 if (waveHigh) {
241 BinStream[bitCnt++] = invert;
242 } else if (!waveHigh) {
243 BinStream[bitCnt++] = invert ^ 1;
244 }
245 waveHigh ^= 1;
246 smplCnt = 0;
247 } else if (!bitCnt) {
248 //first bit
249 waveHigh = (BinStream[i] >= high);
250 smplCnt = 1;
251 } else {
252 smplCnt++;
253 //transition bit oops
254 }
255 } else { //haven't hit new high or new low yet
256 smplCnt++;
257 }
258 }
259 }
260 *size = bitCnt;
261 return errCnt;
262 }
263
264 //by marshmellow
265 void askAmp(uint8_t *BitStream, size_t size)
266 {
267 uint8_t Last = 128;
268 for(size_t i = 1; i<size; i++){
269 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
270 Last = 255;
271 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
272 Last = 0;
273
274 BitStream[i-1] = Last;
275 }
276 return;
277 }
278
279 //by marshmellow
280 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
281 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
282 {
283 if (*size==0) return -1;
284 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
285 if (*clk==0 || start < 0) return -3;
286 if (*invert != 1) *invert = 0;
287 if (amp==1) askAmp(BinStream, *size);
288 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
289
290 uint8_t initLoopMax = 255;
291 if (initLoopMax > *size) initLoopMax = *size;
292 // Detect high and lows
293 //25% clip in case highs and lows aren't clipped [marshmellow]
294 int high, low;
295 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
296 return -2; //just noise
297
298 size_t errCnt = 0;
299 // if clean clipped waves detected run alternate demod
300 if (DetectCleanAskWave(BinStream, *size, high, low)) {
301 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
302 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
303 if (askType) //askman
304 return manrawdecode(BinStream, size, 0);
305 else //askraw
306 return errCnt;
307 }
308 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
309
310 int lastBit; //set first clock check - can go negative
311 size_t i, bitnum = 0; //output counter
312 uint8_t midBit = 0;
313 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
314 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
315 size_t MaxBits = 3072; //max bits to collect
316 lastBit = start - *clk;
317
318 for (i = start; i < *size; ++i) {
319 if (i-lastBit >= *clk-tol){
320 if (BinStream[i] >= high) {
321 BinStream[bitnum++] = *invert;
322 } else if (BinStream[i] <= low) {
323 BinStream[bitnum++] = *invert ^ 1;
324 } else if (i-lastBit >= *clk+tol) {
325 if (bitnum > 0) {
326 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
327 BinStream[bitnum++]=7;
328 errCnt++;
329 }
330 } else { //in tolerance - looking for peak
331 continue;
332 }
333 midBit = 0;
334 lastBit += *clk;
335 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
336 if (BinStream[i] >= high) {
337 BinStream[bitnum++] = *invert;
338 } else if (BinStream[i] <= low) {
339 BinStream[bitnum++] = *invert ^ 1;
340 } else if (i-lastBit >= *clk/2+tol) {
341 BinStream[bitnum] = BinStream[bitnum-1];
342 bitnum++;
343 } else { //in tolerance - looking for peak
344 continue;
345 }
346 midBit = 1;
347 }
348 if (bitnum >= MaxBits) break;
349 }
350 *size = bitnum;
351 return errCnt;
352 }
353
354 //by marshmellow
355 //take 10 and 01 and manchester decode
356 //run through 2 times and take least errCnt
357 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
358 {
359 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
360 size_t i, ii;
361 uint16_t bestErr = 1000, bestRun = 0;
362 if (*size < 16) return -1;
363 //find correct start position [alignment]
364 for (ii=0;ii<2;++ii){
365 for (i=ii; i<*size-3; i+=2)
366 if (BitStream[i]==BitStream[i+1])
367 errCnt++;
368
369 if (bestErr>errCnt){
370 bestErr=errCnt;
371 bestRun=ii;
372 }
373 errCnt=0;
374 }
375 //decode
376 for (i=bestRun; i < *size-3; i+=2){
377 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
378 BitStream[bitnum++]=invert;
379 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
380 BitStream[bitnum++]=invert^1;
381 } else {
382 BitStream[bitnum++]=7;
383 }
384 if(bitnum>MaxBits) break;
385 }
386 *size=bitnum;
387 return bestErr;
388 }
389
390 uint32_t manchesterEncode2Bytes(uint16_t datain) {
391 uint32_t output = 0;
392 uint8_t curBit = 0;
393 for (uint8_t i=0; i<16; i++) {
394 curBit = (datain >> (15-i) & 1);
395 output |= (1<<(((15-i)*2)+curBit));
396 }
397 return output;
398 }
399
400 //by marshmellow
401 //encode binary data into binary manchester
402 int ManchesterEncode(uint8_t *BitStream, size_t size)
403 {
404 size_t modIdx=20000, i=0;
405 if (size>modIdx) return -1;
406 for (size_t idx=0; idx < size; idx++){
407 BitStream[idx+modIdx++] = BitStream[idx];
408 BitStream[idx+modIdx++] = BitStream[idx]^1;
409 }
410 for (; i<(size*2); i++){
411 BitStream[i] = BitStream[i+20000];
412 }
413 return i;
414 }
415
416 //by marshmellow
417 //take 01 or 10 = 1 and 11 or 00 = 0
418 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
419 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
420 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
421 {
422 uint16_t bitnum = 0;
423 uint16_t errCnt = 0;
424 size_t i = offset;
425 uint16_t MaxBits=512;
426 //if not enough samples - error
427 if (*size < 51) return -1;
428 //check for phase change faults - skip one sample if faulty
429 uint8_t offsetA = 1, offsetB = 1;
430 for (; i<48; i+=2){
431 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
432 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
433 }
434 if (!offsetA && offsetB) offset++;
435 for (i=offset; i<*size-3; i+=2){
436 //check for phase error
437 if (BitStream[i+1]==BitStream[i+2]) {
438 BitStream[bitnum++]=7;
439 errCnt++;
440 }
441 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
442 BitStream[bitnum++]=1^invert;
443 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
444 BitStream[bitnum++]=invert;
445 } else {
446 BitStream[bitnum++]=7;
447 errCnt++;
448 }
449 if(bitnum>MaxBits) break;
450 }
451 *size=bitnum;
452 return errCnt;
453 }
454
455 // by marshmellow
456 // demod gProxIIDemod
457 // error returns as -x
458 // success returns start position in BitStream
459 // BitStream must contain previously askrawdemod and biphasedemoded data
460 int gProxII_Demod(uint8_t BitStream[], size_t *size)
461 {
462 size_t startIdx=0;
463 uint8_t preamble[] = {1,1,1,1,1,0};
464
465 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
466 if (errChk == 0) return -3; //preamble not found
467 if (*size != 96) return -2; //should have found 96 bits
468 //check first 6 spacer bits to verify format
469 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
470 //confirmed proper separator bits found
471 //return start position
472 return (int) startIdx;
473 }
474 return -5; //spacer bits not found - not a valid gproxII
475 }
476
477 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
478 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
479 {
480 size_t last_transition = 0;
481 size_t idx = 1;
482 //uint32_t maxVal=0;
483 if (fchigh==0) fchigh=10;
484 if (fclow==0) fclow=8;
485 //set the threshold close to 0 (graph) or 128 std to avoid static
486 uint8_t threshold_value = 123;
487 size_t preLastSample = 0;
488 size_t LastSample = 0;
489 size_t currSample = 0;
490 if ( size < 1024 ) return 0; // not enough samples
491
492 // jump to modulating data by finding the first 4 threshold crossings (or first 2 waves)
493 // in case you have junk or noise at the beginning of the trace...
494 uint8_t thresholdCnt = 0;
495 size_t waveSizeCnt = 0;
496 bool isAboveThreshold = dest[idx++] >= threshold_value;
497 for (; idx < size-20; idx++ ) {
498 if(dest[idx] < threshold_value && isAboveThreshold) {
499 thresholdCnt++;
500 if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break;
501 isAboveThreshold = false;
502 waveSizeCnt = 0;
503 } else if (dest[idx] >= threshold_value && !isAboveThreshold) {
504 thresholdCnt++;
505 if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break;
506 isAboveThreshold = true;
507 waveSizeCnt = 0;
508 } else {
509 waveSizeCnt++;
510 }
511 if (thresholdCnt > 10) break;
512 }
513 if (g_debugMode == 2) prnt("threshold Count reached at %u",idx);
514
515 // Need to threshold first sample
516 if(dest[idx] < threshold_value) dest[0] = 0;
517 else dest[0] = 1;
518 idx++;
519
520 size_t numBits = 0;
521 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
522 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
523 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
524 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
525 for(; idx < size-20; idx++) {
526 // threshold current value
527
528 if (dest[idx] < threshold_value) dest[idx] = 0;
529 else dest[idx] = 1;
530
531 // Check for 0->1 transition
532 if (dest[idx-1] < dest[idx]) {
533 preLastSample = LastSample;
534 LastSample = currSample;
535 currSample = idx-last_transition;
536 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
537 //do nothing with extra garbage
538 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
539 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
540 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
541 dest[numBits-1]=1;
542 }
543 dest[numBits++]=1;
544
545 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
546 //do nothing with beginning garbage and reset.. should be rare..
547 numBits = 0;
548 } 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)
549 dest[numBits++]=1;
550 } else { //9+ = 10 sample waves (or 6+ = 7)
551 dest[numBits++]=0;
552 }
553 last_transition = idx;
554 }
555 }
556 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
557 }
558
559 //translate 11111100000 to 10
560 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
561 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
562 uint8_t invert, uint8_t fchigh, uint8_t fclow)
563 {
564 uint8_t lastval=dest[0];
565 size_t idx=0;
566 size_t numBits=0;
567 uint32_t n=1;
568 for( idx=1; idx < size; idx++) {
569 n++;
570 if (dest[idx]==lastval) continue; //skip until we hit a transition
571
572 //find out how many bits (n) we collected
573 //if lastval was 1, we have a 1->0 crossing
574 if (dest[idx-1]==1) {
575 n = (n * fclow + rfLen/2) / rfLen;
576 } else {// 0->1 crossing
577 n = (n * fchigh + rfLen/2) / rfLen;
578 }
579 if (n == 0) n = 1;
580
581 //add to our destination the bits we collected
582 memset(dest+numBits, dest[idx-1]^invert , n);
583 numBits += n;
584 n=0;
585 lastval=dest[idx];
586 }//end for
587 // if valid extra bits at the end were all the same frequency - add them in
588 if (n > rfLen/fchigh) {
589 if (dest[idx-2]==1) {
590 n = (n * fclow + rfLen/2) / rfLen;
591 } else {
592 n = (n * fchigh + rfLen/2) / rfLen;
593 }
594 memset(dest+numBits, dest[idx-1]^invert , n);
595 numBits += n;
596 }
597 return numBits;
598 }
599
600 //by marshmellow (from holiman's base)
601 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
602 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
603 {
604 // FSK demodulator
605 size = fsk_wave_demod(dest, size, fchigh, fclow);
606 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
607 return size;
608 }
609
610 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
611 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
612 {
613 if (justNoise(dest, *size)) return -1;
614
615 size_t numStart=0, size2=*size, startIdx=0;
616 // FSK demodulator
617 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
618 if (*size < 96*2) return -2;
619 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
620 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
621 // find bitstring in array
622 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
623 if (errChk == 0) return -3; //preamble not found
624
625 numStart = startIdx + sizeof(preamble);
626 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
627 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
628 if (dest[idx] == dest[idx+1]){
629 return -4; //not manchester data
630 }
631 *hi2 = (*hi2<<1)|(*hi>>31);
632 *hi = (*hi<<1)|(*lo>>31);
633 //Then, shift in a 0 or one into low
634 if (dest[idx] && !dest[idx+1]) // 1 0
635 *lo=(*lo<<1)|1;
636 else // 0 1
637 *lo=(*lo<<1)|0;
638 }
639 return (int)startIdx;
640 }
641
642 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
643 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
644 {
645 if (justNoise(dest, *size)) return -1;
646
647 size_t numStart=0, size2=*size, startIdx=0;
648 // FSK demodulator
649 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
650 if (*size < 96) return -2;
651
652 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
653 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
654
655 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
656 if (errChk == 0) return -3; //preamble not found
657
658 numStart = startIdx + sizeof(preamble);
659 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
660 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
661 if (dest[idx] == dest[idx+1])
662 return -4; //not manchester data
663 *hi2 = (*hi2<<1)|(*hi>>31);
664 *hi = (*hi<<1)|(*lo>>31);
665 //Then, shift in a 0 or one into low
666 if (dest[idx] && !dest[idx+1]) // 1 0
667 *lo=(*lo<<1)|1;
668 else // 0 1
669 *lo=(*lo<<1)|0;
670 }
671 return (int)startIdx;
672 }
673
674 int IOdemodFSK(uint8_t *dest, size_t size)
675 {
676 if (justNoise(dest, size)) return -1;
677 //make sure buffer has data
678 if (size < 66*64) return -2;
679 // FSK demodulator
680 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
681 if (size < 65) return -3; //did we get a good demod?
682 //Index map
683 //0 10 20 30 40 50 60
684 //| | | | | | |
685 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
686 //-----------------------------------------------------------------------------
687 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
688 //
689 //XSF(version)facility:codeone+codetwo
690 //Handle the data
691 size_t startIdx = 0;
692 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
693 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
694 if (errChk == 0) return -4; //preamble not found
695
696 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
697 //confirmed proper separator bits found
698 //return start position
699 return (int) startIdx;
700 }
701 return -5;
702 }
703
704 // by marshmellow
705 // find viking preamble 0xF200 in already demoded data
706 int VikingDemod_AM(uint8_t *dest, size_t *size) {
707 //make sure buffer has data
708 if (*size < 64*2) return -2;
709
710 size_t startIdx = 0;
711 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};
712 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
713 if (errChk == 0) return -4; //preamble not found
714 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
715 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
716 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
717 if ( checkCalc != 0xA8 ) return -5;
718 if (*size != 64) return -6;
719 //return start position
720 return (int) startIdx;
721 }
722
723 // find presco preamble 0x10D in already demoded data
724 int PrescoDemod(uint8_t *dest, size_t *size) {
725 //make sure buffer has data
726 if (*size < 64*2) return -2;
727
728 size_t startIdx = 0;
729 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
730 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
731 if (errChk == 0) return -4; //preamble not found
732 //return start position
733 return (int) startIdx;
734 }
735
736 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
737 // BitStream must contain previously askrawdemod and biphasedemoded data
738 int FDXBdemodBI(uint8_t *dest, size_t *size)
739 {
740 //make sure buffer has enough data
741 if (*size < 128) return -1;
742
743 size_t startIdx = 0;
744 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
745
746 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
747 if (errChk == 0) return -2; //preamble not found
748 return (int)startIdx;
749 }
750
751 // by marshmellow
752 // FSK Demod then try to locate an AWID ID
753 int AWIDdemodFSK(uint8_t *dest, size_t *size)
754 {
755 //make sure buffer has enough data
756 if (*size < 96*50) return -1;
757
758 if (justNoise(dest, *size)) return -2;
759
760 // FSK demodulator
761 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
762 if (*size < 96) return -3; //did we get a good demod?
763
764 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
765 size_t startIdx = 0;
766 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
767 if (errChk == 0) return -4; //preamble not found
768 if (*size != 96) return -5;
769 return (int)startIdx;
770 }
771
772 // by marshmellow
773 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
774 int PyramiddemodFSK(uint8_t *dest, size_t *size)
775 {
776 //make sure buffer has data
777 if (*size < 128*50) return -5;
778
779 //test samples are not just noise
780 if (justNoise(dest, *size)) return -1;
781
782 // FSK demodulator
783 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
784 if (*size < 128) return -2; //did we get a good demod?
785
786 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
787 size_t startIdx = 0;
788 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
789 if (errChk == 0) return -4; //preamble not found
790 if (*size != 128) return -3;
791 return (int)startIdx;
792 }
793
794 // by marshmellow
795 // to detect a wave that has heavily clipped (clean) samples
796 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
797 {
798 bool allArePeaks = true;
799 uint16_t cntPeaks=0;
800 size_t loopEnd = 512+160;
801 if (loopEnd > size) loopEnd = size;
802 for (size_t i=160; i<loopEnd; i++){
803 if (dest[i]>low && dest[i]<high)
804 allArePeaks = false;
805 else
806 cntPeaks++;
807 }
808 if (!allArePeaks){
809 if (cntPeaks > 300) return true;
810 }
811 return allArePeaks;
812 }
813 // by marshmellow
814 // to help detect clocks on heavily clipped samples
815 // based on count of low to low
816 int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
817 {
818 uint8_t fndClk[] = {8,16,32,40,50,64,128};
819 size_t startwave;
820 size_t i = 100;
821 size_t minClk = 255;
822 // get to first full low to prime loop and skip incomplete first pulse
823 while ((dest[i] < high) && (i < size))
824 ++i;
825 while ((dest[i] > low) && (i < size))
826 ++i;
827
828 // loop through all samples
829 while (i < size) {
830 // measure from low to low
831 while ((dest[i] > low) && (i < size))
832 ++i;
833 startwave= i;
834 while ((dest[i] < high) && (i < size))
835 ++i;
836 while ((dest[i] > low) && (i < size))
837 ++i;
838 //get minimum measured distance
839 if (i-startwave < minClk && i < size)
840 minClk = i - startwave;
841 }
842 // set clock
843 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
844 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
845 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
846 return fndClk[clkCnt];
847 }
848 return 0;
849 }
850
851 // by marshmellow
852 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
853 // maybe somehow adjust peak trimming value based on samples to fix?
854 // return start index of best starting position for that clock and return clock (by reference)
855 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
856 {
857 size_t i=1;
858 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
859 uint8_t clkEnd = 9;
860 uint8_t loopCnt = 255; //don't need to loop through entire array...
861 if (size <= loopCnt+60) return -1; //not enough samples
862 size -= 60; //sometimes there is a strange end wave - filter out this....
863 //if we already have a valid clock
864 uint8_t clockFnd=0;
865 for (;i<clkEnd;++i)
866 if (clk[i] == *clock) clockFnd = i;
867 //clock found but continue to find best startpos
868
869 //get high and low peak
870 int peak, low;
871 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
872
873 //test for large clean peaks
874 if (!clockFnd){
875 if (DetectCleanAskWave(dest, size, peak, low)==1){
876 int ans = DetectStrongAskClock(dest, size, peak, low);
877 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
878 for (i=clkEnd-1; i>0; i--){
879 if (clk[i] == ans) {
880 *clock = ans;
881 //clockFnd = i;
882 return 0; // for strong waves i don't use the 'best start position' yet...
883 //break; //clock found but continue to find best startpos [not yet]
884 }
885 }
886 }
887 }
888 uint8_t ii;
889 uint8_t clkCnt, tol = 0;
890 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
891 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
892 size_t errCnt = 0;
893 size_t arrLoc, loopEnd;
894
895 if (clockFnd>0) {
896 clkCnt = clockFnd;
897 clkEnd = clockFnd+1;
898 }
899 else clkCnt=1;
900
901 //test each valid clock from smallest to greatest to see which lines up
902 for(; clkCnt < clkEnd; clkCnt++){
903 if (clk[clkCnt] <= 32){
904 tol=1;
905 }else{
906 tol=0;
907 }
908 //if no errors allowed - keep start within the first clock
909 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
910 bestErr[clkCnt]=1000;
911 //try lining up the peaks by moving starting point (try first few clocks)
912 for (ii=0; ii < loopCnt; ii++){
913 if (dest[ii] < peak && dest[ii] > low) continue;
914
915 errCnt=0;
916 // now that we have the first one lined up test rest of wave array
917 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
918 for (i=0; i < loopEnd; ++i){
919 arrLoc = ii + (i * clk[clkCnt]);
920 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
921 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
922 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
923 }else{ //error no peak detected
924 errCnt++;
925 }
926 }
927 //if we found no errors then we can stop here and a low clock (common clocks)
928 // this is correct one - return this clock
929 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
930 if(errCnt==0 && clkCnt<7) {
931 if (!clockFnd) *clock = clk[clkCnt];
932 return ii;
933 }
934 //if we found errors see if it is lowest so far and save it as best run
935 if(errCnt<bestErr[clkCnt]){
936 bestErr[clkCnt]=errCnt;
937 bestStart[clkCnt]=ii;
938 }
939 }
940 }
941 uint8_t iii;
942 uint8_t best=0;
943 for (iii=1; iii<clkEnd; ++iii){
944 if (bestErr[iii] < bestErr[best]){
945 if (bestErr[iii] == 0) bestErr[iii]=1;
946 // current best bit to error ratio vs new bit to error ratio
947 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
948 best = iii;
949 }
950 }
951 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d",clk[iii],bestErr[iii],clk[best],bestStart[best]);
952 }
953 if (!clockFnd) *clock = clk[best];
954 return bestStart[best];
955 }
956
957 //by marshmellow
958 //detect psk clock by reading each phase shift
959 // a phase shift is determined by measuring the sample length of each wave
960 int DetectPSKClock(uint8_t dest[], size_t size, int clock)
961 {
962 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
963 uint16_t loopCnt = 4096; //don't need to loop through entire array...
964 if (size == 0) return 0;
965 if (size<loopCnt) loopCnt = size-20;
966
967 //if we already have a valid clock quit
968 size_t i=1;
969 for (; i < 8; ++i)
970 if (clk[i] == clock) return clock;
971
972 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
973 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
974 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
975 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
976 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
977 fc = countFC(dest, size, 0);
978 if (fc!=2 && fc!=4 && fc!=8) return -1;
979 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
980
981 //find first full wave
982 for (i=160; i<loopCnt; i++){
983 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
984 if (waveStart == 0) {
985 waveStart = i+1;
986 //prnt("DEBUG: waveStart: %d",waveStart);
987 } else {
988 waveEnd = i+1;
989 //prnt("DEBUG: waveEnd: %d",waveEnd);
990 waveLenCnt = waveEnd-waveStart;
991 if (waveLenCnt > fc){
992 firstFullWave = waveStart;
993 fullWaveLen=waveLenCnt;
994 break;
995 }
996 waveStart=0;
997 }
998 }
999 }
1000 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1001
1002 //test each valid clock from greatest to smallest to see which lines up
1003 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1004 lastClkBit = firstFullWave; //set end of wave as clock align
1005 waveStart = 0;
1006 errCnt=0;
1007 peakcnt=0;
1008 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
1009
1010 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1011 //top edge of wave = start of new wave
1012 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1013 if (waveStart == 0) {
1014 waveStart = i+1;
1015 waveLenCnt=0;
1016 } else { //waveEnd
1017 waveEnd = i+1;
1018 waveLenCnt = waveEnd-waveStart;
1019 if (waveLenCnt > fc){
1020 //if this wave is a phase shift
1021 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);
1022 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1023 peakcnt++;
1024 lastClkBit+=clk[clkCnt];
1025 } else if (i<lastClkBit+8){
1026 //noise after a phase shift - ignore
1027 } else { //phase shift before supposed to based on clock
1028 errCnt++;
1029 }
1030 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1031 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1032 }
1033 waveStart=i+1;
1034 }
1035 }
1036 }
1037 if (errCnt == 0){
1038 return clk[clkCnt];
1039 }
1040 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1041 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1042 }
1043 //all tested with errors
1044 //return the highest clk with the most peaks found
1045 uint8_t best=7;
1046 for (i=7; i>=1; i--){
1047 if (peaksdet[i] > peaksdet[best]) {
1048 best = i;
1049 }
1050 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
1051 }
1052 return clk[best];
1053 }
1054
1055 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1056 //find shortest transition from high to low
1057 size_t i = 0;
1058 size_t transition1 = 0;
1059 int lowestTransition = 255;
1060 bool lastWasHigh = false;
1061
1062 //find first valid beginning of a high or low wave
1063 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1064 ++i;
1065 while ((dest[i] < peak && dest[i] > low) && (i < size))
1066 ++i;
1067 lastWasHigh = (dest[i] >= peak);
1068
1069 if (i==size) return 0;
1070 transition1 = i;
1071
1072 for (;i < size; i++) {
1073 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1074 lastWasHigh = (dest[i] >= peak);
1075 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1076 transition1 = i;
1077 }
1078 }
1079 if (lowestTransition == 255) lowestTransition = 0;
1080 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
1081 return lowestTransition;
1082 }
1083
1084 //by marshmellow
1085 //detect nrz clock by reading #peaks vs no peaks(or errors)
1086 int DetectNRZClock(uint8_t dest[], size_t size, int clock)
1087 {
1088 size_t i=0;
1089 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1090 size_t loopCnt = 4096; //don't need to loop through entire array...
1091 if (size == 0) return 0;
1092 if (size<loopCnt) loopCnt = size-20;
1093 //if we already have a valid clock quit
1094 for (; i < 8; ++i)
1095 if (clk[i] == clock) return clock;
1096
1097 //get high and low peak
1098 int peak, low;
1099 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
1100
1101 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
1102 size_t ii;
1103 uint8_t clkCnt;
1104 uint8_t tol = 0;
1105 uint16_t smplCnt = 0;
1106 int16_t peakcnt = 0;
1107 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1108 uint16_t maxPeak = 255;
1109 bool firstpeak = false;
1110 //test for large clipped waves
1111 for (i=0; i<loopCnt; i++){
1112 if (dest[i] >= peak || dest[i] <= low){
1113 if (!firstpeak) continue;
1114 smplCnt++;
1115 } else {
1116 firstpeak=true;
1117 if (smplCnt > 6 ){
1118 if (maxPeak > smplCnt){
1119 maxPeak = smplCnt;
1120 //prnt("maxPk: %d",maxPeak);
1121 }
1122 peakcnt++;
1123 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1124 smplCnt=0;
1125 }
1126 }
1127 }
1128 bool errBitHigh = 0;
1129 bool bitHigh = 0;
1130 uint8_t ignoreCnt = 0;
1131 uint8_t ignoreWindow = 4;
1132 bool lastPeakHigh = 0;
1133 int lastBit = 0;
1134 peakcnt=0;
1135 //test each valid clock from smallest to greatest to see which lines up
1136 for(clkCnt=0; clkCnt < 8; ++clkCnt){
1137 //ignore clocks smaller than smallest peak
1138 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
1139 //try lining up the peaks by moving starting point (try first 256)
1140 for (ii=20; ii < loopCnt; ++ii){
1141 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1142 peakcnt = 0;
1143 bitHigh = false;
1144 ignoreCnt = 0;
1145 lastBit = ii-clk[clkCnt];
1146 //loop through to see if this start location works
1147 for (i = ii; i < size-20; ++i) {
1148 //if we are at a clock bit
1149 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1150 //test high/low
1151 if (dest[i] >= peak || dest[i] <= low) {
1152 //if same peak don't count it
1153 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1154 peakcnt++;
1155 }
1156 lastPeakHigh = (dest[i] >= peak);
1157 bitHigh = true;
1158 errBitHigh = false;
1159 ignoreCnt = ignoreWindow;
1160 lastBit += clk[clkCnt];
1161 } else if (i == lastBit + clk[clkCnt] + tol) {
1162 lastBit += clk[clkCnt];
1163 }
1164 //else if not a clock bit and no peaks
1165 } else if (dest[i] < peak && dest[i] > low){
1166 if (ignoreCnt==0){
1167 bitHigh=false;
1168 if (errBitHigh==true) peakcnt--;
1169 errBitHigh=false;
1170 } else {
1171 ignoreCnt--;
1172 }
1173 // else if not a clock bit but we have a peak
1174 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1175 //error bar found no clock...
1176 errBitHigh=true;
1177 }
1178 }
1179 if(peakcnt>peaksdet[clkCnt]) {
1180 peaksdet[clkCnt]=peakcnt;
1181 }
1182 }
1183 }
1184 }
1185 int iii=7;
1186 uint8_t best=0;
1187 for (iii=7; iii > 0; iii--){
1188 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1189 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
1190 best = iii;
1191 }
1192 } else if (peaksdet[iii] > peaksdet[best]){
1193 best = iii;
1194 }
1195 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);
1196 }
1197
1198 return clk[best];
1199 }
1200
1201 // by marshmellow
1202 // convert psk1 demod to psk2 demod
1203 // only transition waves are 1s
1204 void psk1TOpsk2(uint8_t *BitStream, size_t size)
1205 {
1206 size_t i=1;
1207 uint8_t lastBit=BitStream[0];
1208 for (; i<size; i++){
1209 if (BitStream[i]==7){
1210 //ignore errors
1211 } else if (lastBit!=BitStream[i]){
1212 lastBit=BitStream[i];
1213 BitStream[i]=1;
1214 } else {
1215 BitStream[i]=0;
1216 }
1217 }
1218 return;
1219 }
1220
1221 // by marshmellow
1222 // convert psk2 demod to psk1 demod
1223 // from only transition waves are 1s to phase shifts change bit
1224 void psk2TOpsk1(uint8_t *BitStream, size_t size)
1225 {
1226 uint8_t phase=0;
1227 for (size_t i=0; i<size; i++){
1228 if (BitStream[i]==1){
1229 phase ^=1;
1230 }
1231 BitStream[i]=phase;
1232 }
1233 return;
1234 }
1235
1236 // redesigned by marshmellow adjusted from existing decode functions
1237 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1238 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1239 {
1240 //26 bit 40134 format (don't know other formats)
1241 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};
1242 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};
1243 size_t startidx = 0;
1244 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1245 // if didn't find preamble try again inverting
1246 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1247 *invert ^= 1;
1248 }
1249 if (*size != 64 && *size != 224) return -2;
1250 if (*invert==1)
1251 for (size_t i = startidx; i < *size; i++)
1252 bitStream[i] ^= 1;
1253
1254 return (int) startidx;
1255 }
1256
1257 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1258 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1259 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
1260 if (justNoise(dest, *size)) return -1;
1261 *clk = DetectNRZClock(dest, *size, *clk);
1262 if (*clk==0) return -2;
1263 size_t i, gLen = 4096;
1264 if (gLen>*size) gLen = *size-20;
1265 int high, low;
1266 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1267
1268 uint8_t bit=0;
1269 //convert wave samples to 1's and 0's
1270 for(i=20; i < *size-20; i++){
1271 if (dest[i] >= high) bit = 1;
1272 if (dest[i] <= low) bit = 0;
1273 dest[i] = bit;
1274 }
1275 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1276 size_t lastBit = 0;
1277 size_t numBits = 0;
1278 for(i=21; i < *size-20; i++) {
1279 //if transition detected or large number of same bits - store the passed bits
1280 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1281 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1282 numBits += (i - lastBit + (*clk/4)) / *clk;
1283 lastBit = i-1;
1284 }
1285 }
1286 *size = numBits;
1287 return 0;
1288 }
1289
1290 //by marshmellow
1291 //detects the bit clock for FSK given the high and low Field Clocks
1292 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1293 {
1294 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1295 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1296 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1297 uint8_t rfLensFnd = 0;
1298 uint8_t lastFCcnt = 0;
1299 uint16_t fcCounter = 0;
1300 uint16_t rfCounter = 0;
1301 uint8_t firstBitFnd = 0;
1302 size_t i;
1303 if (size == 0) return 0;
1304
1305 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1306 rfLensFnd=0;
1307 fcCounter=0;
1308 rfCounter=0;
1309 firstBitFnd=0;
1310 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
1311 // prime i to first peak / up transition
1312 for (i = 160; i < size-20; i++)
1313 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1314 break;
1315
1316 for (; i < size-20; i++){
1317 fcCounter++;
1318 rfCounter++;
1319
1320 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1321 continue;
1322 // else new peak
1323 // if we got less than the small fc + tolerance then set it to the small fc
1324 if (fcCounter < fcLow+fcTol)
1325 fcCounter = fcLow;
1326 else //set it to the large fc
1327 fcCounter = fcHigh;
1328
1329 //look for bit clock (rf/xx)
1330 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1331 //not the same size as the last wave - start of new bit sequence
1332 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1333 for (int ii=0; ii<15; ii++){
1334 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
1335 rfCnts[ii]++;
1336 rfCounter = 0;
1337 break;
1338 }
1339 }
1340 if (rfCounter > 0 && rfLensFnd < 15){
1341 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1342 rfCnts[rfLensFnd]++;
1343 rfLens[rfLensFnd++] = rfCounter;
1344 }
1345 } else {
1346 firstBitFnd++;
1347 }
1348 rfCounter=0;
1349 lastFCcnt=fcCounter;
1350 }
1351 fcCounter=0;
1352 }
1353 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1354
1355 for (i=0; i<15; i++){
1356 //get highest 2 RF values (might need to get more values to compare or compare all?)
1357 if (rfCnts[i]>rfCnts[rfHighest]){
1358 rfHighest3=rfHighest2;
1359 rfHighest2=rfHighest;
1360 rfHighest=i;
1361 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1362 rfHighest3=rfHighest2;
1363 rfHighest2=i;
1364 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1365 rfHighest3=i;
1366 }
1367 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
1368 }
1369 // set allowed clock remainder tolerance to be 1 large field clock length+1
1370 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1371 uint8_t tol1 = fcHigh+1;
1372
1373 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
1374
1375 // loop to find the highest clock that has a remainder less than the tolerance
1376 // compare samples counted divided by
1377 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1378 int ii=7;
1379 for (; ii>=2; ii--){
1380 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1381 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1382 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
1383 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
1384 break;
1385 }
1386 }
1387 }
1388 }
1389
1390 if (ii<0) return 0; // oops we went too far
1391
1392 return clk[ii];
1393 }
1394
1395 //by marshmellow
1396 //countFC is to detect the field clock lengths.
1397 //counts and returns the 2 most common wave lengths
1398 //mainly used for FSK field clock detection
1399 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
1400 {
1401 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1402 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1403 uint8_t fcLensFnd = 0;
1404 uint8_t lastFCcnt = 0;
1405 uint8_t fcCounter = 0;
1406 size_t i;
1407 if (size < 180) return 0;
1408
1409 // prime i to first up transition
1410 for (i = 160; i < size-20; i++)
1411 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1412 break;
1413
1414 for (; i < size-20; i++){
1415 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1416 // new up transition
1417 fcCounter++;
1418 if (fskAdj){
1419 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1420 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1421 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1422 if ((fcCounter==9) || fcCounter==4) fcCounter++;
1423 // save last field clock count (fc/xx)
1424 lastFCcnt = fcCounter;
1425 }
1426 // find which fcLens to save it to:
1427 for (int ii=0; ii<15; ii++){
1428 if (fcLens[ii]==fcCounter){
1429 fcCnts[ii]++;
1430 fcCounter=0;
1431 break;
1432 }
1433 }
1434 if (fcCounter>0 && fcLensFnd<15){
1435 //add new fc length
1436 fcCnts[fcLensFnd]++;
1437 fcLens[fcLensFnd++]=fcCounter;
1438 }
1439 fcCounter=0;
1440 } else {
1441 // count sample
1442 fcCounter++;
1443 }
1444 }
1445
1446 uint8_t best1=14, best2=14, best3=14;
1447 uint16_t maxCnt1=0;
1448 // go through fclens and find which ones are bigest 2
1449 for (i=0; i<15; i++){
1450 // get the 3 best FC values
1451 if (fcCnts[i]>maxCnt1) {
1452 best3=best2;
1453 best2=best1;
1454 maxCnt1=fcCnts[i];
1455 best1=i;
1456 } else if(fcCnts[i]>fcCnts[best2]){
1457 best3=best2;
1458 best2=i;
1459 } else if(fcCnts[i]>fcCnts[best3]){
1460 best3=i;
1461 }
1462 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]);
1463 }
1464 if (fcLens[best1]==0) return 0;
1465 uint8_t fcH=0, fcL=0;
1466 if (fcLens[best1]>fcLens[best2]){
1467 fcH=fcLens[best1];
1468 fcL=fcLens[best2];
1469 } else{
1470 fcH=fcLens[best2];
1471 fcL=fcLens[best1];
1472 }
1473 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1474 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]);
1475 return 0; //lots of waves not psk or fsk
1476 }
1477 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1478
1479 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
1480 if (fskAdj) return fcs;
1481 return fcLens[best1];
1482 }
1483
1484 //by marshmellow - demodulate PSK1 wave
1485 //uses wave lengths (# Samples)
1486 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1487 {
1488 if (size == 0) return -1;
1489 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1490 if (*size<loopCnt) loopCnt = *size;
1491
1492 size_t numBits=0;
1493 uint8_t curPhase = *invert;
1494 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1495 uint8_t fc=0, fullWaveLen=0, tol=1;
1496 uint16_t errCnt=0, waveLenCnt=0;
1497 fc = countFC(dest, *size, 0);
1498 if (fc!=2 && fc!=4 && fc!=8) return -1;
1499 //PrintAndLog("DEBUG: FC: %d",fc);
1500 *clock = DetectPSKClock(dest, *size, *clock);
1501 if (*clock == 0) return -1;
1502 // jump to modulating data by finding the first 2 threshold crossings (or first 1 waves)
1503 // in case you have junk or noise at the beginning of the trace...
1504 uint8_t thresholdCnt = 0;
1505 size_t waveSizeCnt = 0;
1506 uint8_t threshold_value = 123; //-5
1507 bool isAboveThreshold = dest[i++] >= threshold_value;
1508 for (; i < *size-20; i++ ) {
1509 if(dest[i] < threshold_value && isAboveThreshold) {
1510 thresholdCnt++;
1511 if (thresholdCnt > 2 && waveSizeCnt < fc+1) break;
1512 isAboveThreshold = false;
1513 waveSizeCnt = 0;
1514 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
1515 thresholdCnt++;
1516 if (thresholdCnt > 2 && waveSizeCnt < fc+1) break;
1517 isAboveThreshold = true;
1518 waveSizeCnt = 0;
1519 } else {
1520 waveSizeCnt++;
1521 }
1522 if (thresholdCnt > 10) break;
1523 }
1524 if (g_debugMode == 2) prnt("DEBUG PSK: threshold Count reached at %u, count: %u",i, thresholdCnt);
1525
1526
1527 int avgWaveVal=0, lastAvgWaveVal=0;
1528 waveStart = i+1;
1529 //find first phase shift
1530 for (; i<loopCnt; i++){
1531 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1532 waveEnd = i+1;
1533 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1534 waveLenCnt = waveEnd-waveStart;
1535 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1536 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1537 firstFullWave = waveStart;
1538 fullWaveLen=waveLenCnt;
1539 //if average wave value is > graph 0 then it is an up wave or a 1
1540 if (lastAvgWaveVal > threshold_value) curPhase ^= 1; //fudge graph 0 a little 123 vs 128
1541 break;
1542 }
1543 waveStart = i+1;
1544 avgWaveVal = 0;
1545 }
1546 avgWaveVal += dest[i+2];
1547 }
1548 if (firstFullWave == 0) {
1549 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1550 // so skip a little to ensure we are past any Start Signal
1551 firstFullWave = 160;
1552 memset(dest, curPhase, firstFullWave / *clock);
1553 } else {
1554 memset(dest, curPhase^1, firstFullWave / *clock);
1555 }
1556 //advance bits
1557 numBits += (firstFullWave / *clock);
1558 //set start of wave as clock align
1559 lastClkBit = firstFullWave;
1560 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
1561 if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1562 waveStart = 0;
1563 dest[numBits++] = curPhase; //set first read bit
1564 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1565 //top edge of wave = start of new wave
1566 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1567 if (waveStart == 0) {
1568 waveStart = i+1;
1569 waveLenCnt = 0;
1570 avgWaveVal = dest[i+1];
1571 } else { //waveEnd
1572 waveEnd = i+1;
1573 waveLenCnt = waveEnd-waveStart;
1574 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1575 if (waveLenCnt > fc){
1576 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1577 //this wave is a phase shift
1578 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1579 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1580 curPhase ^= 1;
1581 dest[numBits++] = curPhase;
1582 lastClkBit += *clock;
1583 } else if (i < lastClkBit+10+fc){
1584 //noise after a phase shift - ignore
1585 } else { //phase shift before supposed to based on clock
1586 errCnt++;
1587 dest[numBits++] = 7;
1588 }
1589 } else if (i+1 > lastClkBit + *clock + tol + fc){
1590 lastClkBit += *clock; //no phase shift but clock bit
1591 dest[numBits++] = curPhase;
1592 }
1593 avgWaveVal = 0;
1594 waveStart = i+1;
1595 }
1596 }
1597 avgWaveVal += dest[i+1];
1598 }
1599 *size = numBits;
1600 return errCnt;
1601 }
1602
1603 //by marshmellow
1604 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1605 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1606 size_t bufsize = *size;
1607 //need to loop through all samples and identify our clock, look for the ST pattern
1608 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1609 int clk = 0;
1610 int tol = 0;
1611 int i, j, skip, start, end, low, high, minClk, waveStart;
1612 bool complete = false;
1613 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1614 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
1615 size_t testsize = (bufsize < 512) ? bufsize : 512;
1616 int phaseoff = 0;
1617 high = low = 128;
1618 memset(tmpbuff, 0, sizeof(tmpbuff));
1619
1620 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1621 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1622 return false; //just noise
1623 }
1624 i = 0;
1625 j = 0;
1626 minClk = 255;
1627 // get to first full low to prime loop and skip incomplete first pulse
1628 while ((buffer[i] < high) && (i < bufsize))
1629 ++i;
1630 while ((buffer[i] > low) && (i < bufsize))
1631 ++i;
1632 skip = i;
1633
1634 // populate tmpbuff buffer with pulse lengths
1635 while (i < bufsize) {
1636 // measure from low to low
1637 while ((buffer[i] > low) && (i < bufsize))
1638 ++i;
1639 start= i;
1640 while ((buffer[i] < high) && (i < bufsize))
1641 ++i;
1642 //first high point for this wave
1643 waveStart = i;
1644 while ((buffer[i] > low) && (i < bufsize))
1645 ++i;
1646 if (j >= (bufsize/32)) {
1647 break;
1648 }
1649 waveLen[j] = i - waveStart; //first high to first low
1650 tmpbuff[j++] = i - start;
1651 if (i-start < minClk && i < bufsize) {
1652 minClk = i - start;
1653 }
1654 }
1655 // set clock - might be able to get this externally and remove this work...
1656 if (!clk) {
1657 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1658 tol = fndClk[clkCnt]/8;
1659 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1660 clk=fndClk[clkCnt];
1661 break;
1662 }
1663 }
1664 // clock not found - ERROR
1665 if (!clk) {
1666 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1667 return false;
1668 }
1669 } else tol = clk/8;
1670
1671 *foundclock = clk;
1672
1673 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1674 start = -1;
1675 for (i = 0; i < j - 4; ++i) {
1676 skip += tmpbuff[i];
1677 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1678 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
1679 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
1680 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1681 start = i + 3;
1682 break;
1683 }
1684 }
1685 }
1686 }
1687 }
1688 // first ST not found - ERROR
1689 if (start < 0) {
1690 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1691 return false;
1692 } else {
1693 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
1694 }
1695 if (waveLen[i+2] > clk*1+tol)
1696 phaseoff = 0;
1697 else
1698 phaseoff = clk/2;
1699
1700 // skip over the remainder of ST
1701 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1702
1703 // now do it again to find the end
1704 end = skip;
1705 for (i += 3; i < j - 4; ++i) {
1706 end += tmpbuff[i];
1707 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1708 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
1709 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
1710 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1711 complete = true;
1712 break;
1713 }
1714 }
1715 }
1716 }
1717 }
1718 end -= phaseoff;
1719 //didn't find second ST - ERROR
1720 if (!complete) {
1721 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1722 return false;
1723 }
1724 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);
1725 //now begin to trim out ST so we can use normal demod cmds
1726 start = skip;
1727 size_t datalen = end - start;
1728 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1729 if ( clk - (datalen % clk) <= clk/8) {
1730 // padd the amount off - could be problematic... but shouldn't happen often
1731 datalen += clk - (datalen % clk);
1732 } else if ( (datalen % clk) <= clk/8 ) {
1733 // padd the amount off - could be problematic... but shouldn't happen often
1734 datalen -= datalen % clk;
1735 } else {
1736 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1737 return false;
1738 }
1739 // if datalen is less than one t55xx block - ERROR
1740 if (datalen/clk < 8*4) {
1741 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1742 return false;
1743 }
1744 size_t dataloc = start;
1745 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1746 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1747 for ( i=0; i <= (clk/8); ++i ) {
1748 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1749 dataloc -= i;
1750 break;
1751 }
1752 }
1753 }
1754
1755 size_t newloc = 0;
1756 i=0;
1757 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1758
1759 // warning - overwriting buffer given with raw wave data with ST removed...
1760 while ( dataloc < bufsize-(clk/2) ) {
1761 //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)
1762 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1763 for(i=0; i < clk/2-tol; ++i) {
1764 buffer[dataloc+i] = high+5;
1765 }
1766 }
1767 for (i=0; i<datalen; ++i) {
1768 if (i+newloc < bufsize) {
1769 if (i+newloc < dataloc)
1770 buffer[i+newloc] = buffer[dataloc];
1771
1772 dataloc++;
1773 }
1774 }
1775 newloc += i;
1776 //skip next ST - we just assume it will be there from now on...
1777 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1778 dataloc += clk*4;
1779 }
1780 *size = newloc;
1781 return true;
1782 }
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