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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 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
154 }
155
156 // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
157 // fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
158 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
159 // Sanity check. If preamble length is bigger than bitstream length.
160 if ( *size <= pLen ) return false;
161
162 uint8_t foundCnt = 0;
163 for (size_t idx = 0; idx < *size - pLen; idx++) {
164 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
165 //first index found
166 foundCnt++;
167 if (foundCnt == 1) {
168 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
169 *startIdx = idx;
170 if (findone) return true;
171 } else if (foundCnt == 2) {
172 *size = idx - *startIdx;
173 return true;
174 }
175 }
176 }
177 return false;
178 }
179
180 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
181 size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
182 size_t i = 0;
183 size_t waveSizeCnt = 0;
184 uint8_t thresholdCnt = 0;
185 bool isAboveThreshold = dest[i++] >= threshold_value;
186 for (; i < size-20; i++ ) {
187 if(dest[i] < threshold_value && isAboveThreshold) {
188 thresholdCnt++;
189 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
190 isAboveThreshold = false;
191 waveSizeCnt = 0;
192 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
193 thresholdCnt++;
194 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
195 isAboveThreshold = true;
196 waveSizeCnt = 0;
197 } else {
198 waveSizeCnt++;
199 }
200 if (thresholdCnt > 10) break;
201 }
202 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
203 return i;
204 }
205
206 //by marshmellow
207 //takes 1s and 0s and searches for EM410x format - output EM ID
208 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
209 {
210 //sanity checks
211 if (*size < 64) return 0;
212 if (BitStream[1]>1) return 0; //allow only 1s and 0s
213
214 // 111111111 bit pattern represent start of frame
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 uint8_t errChk = 0;
218 uint8_t FmtLen = 10; // sets of 4 bits = end data
219 *startIdx = 0;
220 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
221 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
222 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
223
224 //skip last 4bit parity row for simplicity
225 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
226 if (*size == 40) { // std em410x format
227 *hi = 0;
228 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
229 } else if (*size == 88) { // long em format
230 *hi = (bytebits_to_byte(BitStream, 24));
231 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
232 } else {
233 return 0;
234 }
235 return 1;
236 }
237
238 //by marshmellow
239 //demodulates strong heavily clipped samples
240 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
241 {
242 *startIdx=0;
243 size_t bitCnt=0, smplCnt=1, errCnt=0;
244 bool waveHigh = (BinStream[0] >= high);
245 for (size_t i=1; i < *size; i++){
246 if (BinStream[i] >= high && waveHigh){
247 smplCnt++;
248 } else if (BinStream[i] <= low && !waveHigh){
249 smplCnt++;
250 } else { //transition
251 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
252 if (smplCnt > clk-(clk/4)-1) { //full clock
253 if (smplCnt > clk + (clk/4)+1) { //too many samples
254 errCnt++;
255 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
256 BinStream[bitCnt++] = 7;
257 } else if (waveHigh) {
258 BinStream[bitCnt++] = invert;
259 BinStream[bitCnt++] = invert;
260 } else if (!waveHigh) {
261 BinStream[bitCnt++] = invert ^ 1;
262 BinStream[bitCnt++] = invert ^ 1;
263 }
264 if (*startIdx==0) *startIdx = i-clk;
265 waveHigh = !waveHigh;
266 smplCnt = 0;
267 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
268 if (waveHigh) {
269 BinStream[bitCnt++] = invert;
270 } else if (!waveHigh) {
271 BinStream[bitCnt++] = invert ^ 1;
272 }
273 if (*startIdx==0) *startIdx = i-(clk/2);
274 waveHigh = !waveHigh;
275 smplCnt = 0;
276 } else {
277 smplCnt++;
278 //transition bit oops
279 }
280 } else { //haven't hit new high or new low yet
281 smplCnt++;
282 }
283 }
284 }
285 *size = bitCnt;
286 return errCnt;
287 }
288
289 //by marshmellow
290 //amplify based on ask edge detection
291 void askAmp(uint8_t *BitStream, size_t size)
292 {
293 uint8_t Last = 128;
294 for(size_t i = 1; i<size; i++){
295 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
296 Last = 255;
297 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
298 Last = 0;
299
300 BitStream[i-1] = Last;
301 }
302 return;
303 }
304
305 //by marshmellow
306 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
307 int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
308 if (*size==0) return -1;
309 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
310 if (*clk==0 || start < 0) return -3;
311 if (*invert != 1) *invert = 0;
312 if (amp==1) askAmp(BinStream, *size);
313 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
314
315 //start pos from detect ask clock is 1/2 clock offset
316 // NOTE: can be negative (demod assumes rest of wave was there)
317 *startIdx = start - (*clk/2);
318 uint8_t initLoopMax = 255;
319 if (initLoopMax > *size) initLoopMax = *size;
320 // Detect high and lows
321 //25% clip in case highs and lows aren't clipped [marshmellow]
322 int high, low;
323 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
324 return -2; //just noise
325
326 size_t errCnt = 0;
327 // if clean clipped waves detected run alternate demod
328 if (DetectCleanAskWave(BinStream, *size, high, low)) {
329 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
330 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
331 if (askType) { //askman
332 uint8_t alignPos = 0;
333 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
334 *startIdx += *clk/2 * alignPos;
335 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
336 return errCnt;
337 } else { //askraw
338 return errCnt;
339 }
340 }
341 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
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
388 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
389 int start = 0;
390 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
391 }
392 //by marshmellow
393 //take 10 and 01 and manchester decode
394 //run through 2 times and take least errCnt
395 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos)
396 {
397 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
398 size_t i, ii;
399 uint16_t bestErr = 1000, bestRun = 0;
400 if (*size < 16) return -1;
401 //find correct start position [alignment]
402 for (ii=0;ii<2;++ii){
403 for (i=ii; i<*size-3; i+=2)
404 if (BitStream[i]==BitStream[i+1])
405 errCnt++;
406
407 if (bestErr>errCnt){
408 bestErr=errCnt;
409 bestRun=ii;
410 }
411 errCnt=0;
412 }
413 *alignPos=bestRun;
414 //decode
415 for (i=bestRun; i < *size-3; i+=2){
416 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
417 BitStream[bitnum++]=invert;
418 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
419 BitStream[bitnum++]=invert^1;
420 } else {
421 BitStream[bitnum++]=7;
422 }
423 if(bitnum>MaxBits) break;
424 }
425 *size=bitnum;
426 return bestErr;
427 }
428
429 uint32_t manchesterEncode2Bytes(uint16_t datain) {
430 uint32_t output = 0;
431 uint8_t curBit = 0;
432 for (uint8_t i=0; i<16; i++) {
433 curBit = (datain >> (15-i) & 1);
434 output |= (1<<(((15-i)*2)+curBit));
435 }
436 return output;
437 }
438
439 //by marshmellow
440 //encode binary data into binary manchester
441 int ManchesterEncode(uint8_t *BitStream, size_t size)
442 {
443 size_t modIdx=20000, i=0;
444 if (size>modIdx) return -1;
445 for (size_t idx=0; idx < size; idx++){
446 BitStream[idx+modIdx++] = BitStream[idx];
447 BitStream[idx+modIdx++] = BitStream[idx]^1;
448 }
449 for (; i<(size*2); i++){
450 BitStream[i] = BitStream[i+20000];
451 }
452 return i;
453 }
454
455 //by marshmellow
456 //take 01 or 10 = 1 and 11 or 00 = 0
457 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
458 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
459 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
460 {
461 uint16_t bitnum = 0;
462 uint16_t errCnt = 0;
463 size_t i = offset;
464 uint16_t MaxBits=512;
465 //if not enough samples - error
466 if (*size < 51) return -1;
467 //check for phase change faults - skip one sample if faulty
468 uint8_t offsetA = 1, offsetB = 1;
469 for (; i<48; i+=2){
470 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
471 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
472 }
473 if (!offsetA && offsetB) offset++;
474 for (i=offset; i<*size-3; i+=2){
475 //check for phase error
476 if (BitStream[i+1]==BitStream[i+2]) {
477 BitStream[bitnum++]=7;
478 errCnt++;
479 }
480 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
481 BitStream[bitnum++]=1^invert;
482 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
483 BitStream[bitnum++]=invert;
484 } else {
485 BitStream[bitnum++]=7;
486 errCnt++;
487 }
488 if(bitnum>MaxBits) break;
489 }
490 *size=bitnum;
491 return errCnt;
492 }
493
494 // by marshmellow
495 // demod gProxIIDemod
496 // error returns as -x
497 // success returns start position in BitStream
498 // BitStream must contain previously askrawdemod and biphasedemoded data
499 int gProxII_Demod(uint8_t BitStream[], size_t *size)
500 {
501 size_t startIdx=0;
502 uint8_t preamble[] = {1,1,1,1,1,0};
503
504 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
505 if (errChk == 0) return -3; //preamble not found
506 if (*size != 96) return -2; //should have found 96 bits
507 //check first 6 spacer bits to verify format
508 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
509 //confirmed proper separator bits found
510 //return start position
511 return (int) startIdx;
512 }
513 return -5; //spacer bits not found - not a valid gproxII
514 }
515
516 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
517 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx)
518 {
519 size_t last_transition = 0;
520 size_t idx = 1;
521 if (fchigh==0) fchigh=10;
522 if (fclow==0) fclow=8;
523 //set the threshold close to 0 (graph) or 128 std to avoid static
524 uint8_t threshold_value = 123;
525 size_t preLastSample = 0;
526 size_t LastSample = 0;
527 size_t currSample = 0;
528 if ( size < 1024 ) return 0; // not enough samples
529
530 //find start of modulating data in trace
531 idx = findModStart(dest, size, threshold_value, fchigh);
532 // Need to threshold first sample
533 if(dest[idx] < threshold_value) dest[0] = 0;
534 else dest[0] = 1;
535
536 last_transition = idx;
537 idx++;
538 size_t numBits = 0;
539 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
540 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
541 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
542 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
543 for(; idx < size; idx++) {
544 // threshold current value
545 if (dest[idx] < threshold_value) dest[idx] = 0;
546 else dest[idx] = 1;
547
548 // Check for 0->1 transition
549 if (dest[idx-1] < dest[idx]) {
550 preLastSample = LastSample;
551 LastSample = currSample;
552 currSample = idx-last_transition;
553 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
554 //do nothing with extra garbage
555 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
556 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
557 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
558 dest[numBits-1]=1;
559 }
560 dest[numBits++]=1;
561 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
562 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
563 //do nothing with beginning garbage and reset.. should be rare..
564 numBits = 0;
565 } 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)
566 dest[numBits++]=1;
567 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
568 } else { //9+ = 10 sample waves (or 6+ = 7)
569 dest[numBits++]=0;
570 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
571 }
572 last_transition = idx;
573 }
574 }
575 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
576 }
577
578 //translate 11111100000 to 10
579 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
580 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
581 uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx)
582 {
583 uint8_t lastval=dest[0];
584 size_t idx=0;
585 size_t numBits=0;
586 uint32_t n=1;
587 for( idx=1; idx < size; idx++) {
588 n++;
589 if (dest[idx]==lastval) continue; //skip until we hit a transition
590
591 //find out how many bits (n) we collected (use 1/2 clk tolerance)
592 //if lastval was 1, we have a 1->0 crossing
593 if (dest[idx-1]==1) {
594 n = (n * fclow + rfLen/2) / rfLen;
595 } else {// 0->1 crossing
596 n = (n * fchigh + rfLen/2) / rfLen;
597 }
598 if (n == 0) n = 1;
599
600 //first transition - save startidx
601 if (numBits == 0) {
602 if (lastval == 1) { //high to low
603 *startIdx += (fclow * idx) - (n*rfLen);
604 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
605 } else {
606 *startIdx += (fchigh * idx) - (n*rfLen);
607 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
608 }
609 }
610
611 //add to our destination the bits we collected
612 memset(dest+numBits, dest[idx-1]^invert , n);
613 numBits += n;
614 n=0;
615 lastval=dest[idx];
616 }//end for
617 // if valid extra bits at the end were all the same frequency - add them in
618 if (n > rfLen/fchigh) {
619 if (dest[idx-2]==1) {
620 n = (n * fclow + rfLen/2) / rfLen;
621 } else {
622 n = (n * fchigh + rfLen/2) / rfLen;
623 }
624 memset(dest+numBits, dest[idx-1]^invert , n);
625 numBits += n;
626 }
627 return numBits;
628 }
629
630 //by marshmellow (from holiman's base)
631 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
632 int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
633 // FSK demodulator
634 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
635 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
636 return size;
637 }
638
639 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
640 int startIdx=0;
641 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
642 }
643
644 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
645 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
646 {
647 if (justNoise(dest, *size)) return -1;
648
649 size_t numStart=0, size2=*size, startIdx=0;
650 // FSK demodulator
651 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
652 if (*size < 96*2) return -2;
653 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
654 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
655 // find bitstring in array
656 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
657 if (errChk == 0) return -3; //preamble not found
658
659 numStart = startIdx + sizeof(preamble);
660 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
661 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
662 if (dest[idx] == dest[idx+1]){
663 return -4; //not manchester data
664 }
665 *hi2 = (*hi2<<1)|(*hi>>31);
666 *hi = (*hi<<1)|(*lo>>31);
667 //Then, shift in a 0 or one into low
668 if (dest[idx] && !dest[idx+1]) // 1 0
669 *lo=(*lo<<1)|1;
670 else // 0 1
671 *lo=(*lo<<1)|0;
672 }
673 return (int)startIdx;
674 }
675
676 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
677 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
678 {
679 if (justNoise(dest, *size)) return -1;
680
681 size_t numStart=0, size2=*size, startIdx=0;
682 // FSK demodulator
683 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
684 if (*size < 96) return -2;
685
686 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
687 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
688
689 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
690 if (errChk == 0) return -3; //preamble not found
691
692 numStart = startIdx + sizeof(preamble);
693 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
694 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
695 if (dest[idx] == dest[idx+1])
696 return -4; //not manchester data
697 *hi2 = (*hi2<<1)|(*hi>>31);
698 *hi = (*hi<<1)|(*lo>>31);
699 //Then, shift in a 0 or one into low
700 if (dest[idx] && !dest[idx+1]) // 1 0
701 *lo=(*lo<<1)|1;
702 else // 0 1
703 *lo=(*lo<<1)|0;
704 }
705 return (int)startIdx;
706 }
707
708 int IOdemodFSK(uint8_t *dest, size_t size)
709 {
710 if (justNoise(dest, size)) return -1;
711 //make sure buffer has data
712 if (size < 66*64) return -2;
713 // FSK demodulator
714 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
715 if (size < 65) return -3; //did we get a good demod?
716 //Index map
717 //0 10 20 30 40 50 60
718 //| | | | | | |
719 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
720 //-----------------------------------------------------------------------------
721 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
722 //
723 //XSF(version)facility:codeone+codetwo
724 //Handle the data
725 size_t startIdx = 0;
726 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
727 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
728 if (errChk == 0) return -4; //preamble not found
729
730 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
731 //confirmed proper separator bits found
732 //return start position
733 return (int) startIdx;
734 }
735 return -5;
736 }
737
738 // by marshmellow
739 // find viking preamble 0xF200 in already demoded data
740 int VikingDemod_AM(uint8_t *dest, size_t *size) {
741 //make sure buffer has data
742 if (*size < 64*2) return -2;
743
744 size_t startIdx = 0;
745 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};
746 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
747 if (errChk == 0) return -4; //preamble not found
748 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
749 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
750 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
751 if ( checkCalc != 0xA8 ) return -5;
752 if (*size != 64) return -6;
753 //return start position
754 return (int) startIdx;
755 }
756
757 // find presco preamble 0x10D in already demoded data
758 int PrescoDemod(uint8_t *dest, size_t *size) {
759 //make sure buffer has data
760 if (*size < 64*2) return -2;
761
762 size_t startIdx = 0;
763 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
764 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
765 if (errChk == 0) return -4; //preamble not found
766 //return start position
767 return (int) startIdx;
768 }
769
770 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
771 // BitStream must contain previously askrawdemod and biphasedemoded data
772 int FDXBdemodBI(uint8_t *dest, size_t *size)
773 {
774 //make sure buffer has enough data
775 if (*size < 128) return -1;
776
777 size_t startIdx = 0;
778 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
779
780 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
781 if (errChk == 0) return -2; //preamble not found
782 return (int)startIdx;
783 }
784
785 // by marshmellow
786 // FSK Demod then try to locate an AWID ID
787 int AWIDdemodFSK(uint8_t *dest, size_t *size)
788 {
789 //make sure buffer has enough data
790 if (*size < 96*50) return -1;
791
792 if (justNoise(dest, *size)) return -2;
793
794 // FSK demodulator
795 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
796 if (*size < 96) return -3; //did we get a good demod?
797
798 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
799 size_t startIdx = 0;
800 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
801 if (errChk == 0) return -4; //preamble not found
802 if (*size != 96) return -5;
803 return (int)startIdx;
804 }
805
806 // by marshmellow
807 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
808 int PyramiddemodFSK(uint8_t *dest, size_t *size)
809 {
810 //make sure buffer has data
811 if (*size < 128*50) return -5;
812
813 //test samples are not just noise
814 if (justNoise(dest, *size)) return -1;
815
816 // FSK demodulator
817 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
818 if (*size < 128) return -2; //did we get a good demod?
819
820 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
821 size_t startIdx = 0;
822 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
823 if (errChk == 0) return -4; //preamble not found
824 if (*size != 128) return -3;
825 return (int)startIdx;
826 }
827
828 // by marshmellow
829 // to detect a wave that has heavily clipped (clean) samples
830 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
831 {
832 bool allArePeaks = true;
833 uint16_t cntPeaks=0;
834 size_t loopEnd = 512+160;
835 if (loopEnd > size) loopEnd = size;
836 for (size_t i=160; i<loopEnd; i++){
837 if (dest[i]>low && dest[i]<high)
838 allArePeaks = false;
839 else
840 cntPeaks++;
841 }
842 if (!allArePeaks){
843 if (cntPeaks > 300) return true;
844 }
845 return allArePeaks;
846 }
847 // by marshmellow
848 // to help detect clocks on heavily clipped samples
849 // based on count of low to low
850 int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock) {
851 uint8_t fndClk[] = {8,16,32,40,50,64,128};
852 size_t startwave;
853 size_t i = 100;
854 size_t minClk = 255;
855 int shortestWaveIdx = 0;
856 // get to first full low to prime loop and skip incomplete first pulse
857 while ((dest[i] < high) && (i < size))
858 ++i;
859 while ((dest[i] > low) && (i < size))
860 ++i;
861
862 // loop through all samples
863 while (i < size) {
864 // measure from low to low
865 while ((dest[i] > low) && (i < size))
866 ++i;
867 startwave = i;
868 while ((dest[i] < high) && (i < size))
869 ++i;
870 while ((dest[i] > low) && (i < size))
871 ++i;
872 //get minimum measured distance
873 if (i-startwave < minClk && i < size) {
874 minClk = i - startwave;
875 shortestWaveIdx = startwave;
876 }
877 }
878 // set clock
879 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
880 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
881 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) {
882 *clock = fndClk[clkCnt];
883 return shortestWaveIdx;
884 }
885 }
886 return 0;
887 }
888
889 // by marshmellow
890 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
891 // maybe somehow adjust peak trimming value based on samples to fix?
892 // return start index of best starting position for that clock and return clock (by reference)
893 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
894 {
895 size_t i=1;
896 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
897 uint8_t clkEnd = 9;
898 uint8_t loopCnt = 255; //don't need to loop through entire array...
899 if (size <= loopCnt+60) return -1; //not enough samples
900 size -= 60; //sometimes there is a strange end wave - filter out this....
901 //if we already have a valid clock
902 uint8_t clockFnd=0;
903 for (;i<clkEnd;++i)
904 if (clk[i] == *clock) clockFnd = i;
905 //clock found but continue to find best startpos
906
907 //get high and low peak
908 int peak, low;
909 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
910
911 //test for large clean peaks
912 if (!clockFnd){
913 if (DetectCleanAskWave(dest, size, peak, low)==1){
914 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
915 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
916 if (ans > 0) {
917 return ans; //return shortest wave start position
918 }
919 }
920 }
921 uint8_t ii;
922 uint8_t clkCnt, tol = 0;
923 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
924 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
925 size_t errCnt = 0;
926 size_t arrLoc, loopEnd;
927
928 if (clockFnd>0) {
929 clkCnt = clockFnd;
930 clkEnd = clockFnd+1;
931 }
932 else clkCnt=1;
933
934 //test each valid clock from smallest to greatest to see which lines up
935 for(; clkCnt < clkEnd; clkCnt++){
936 if (clk[clkCnt] <= 32){
937 tol=1;
938 }else{
939 tol=0;
940 }
941 //if no errors allowed - keep start within the first clock
942 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
943 bestErr[clkCnt]=1000;
944 //try lining up the peaks by moving starting point (try first few clocks)
945 for (ii=0; ii < loopCnt; ii++){
946 if (dest[ii] < peak && dest[ii] > low) continue;
947
948 errCnt=0;
949 // now that we have the first one lined up test rest of wave array
950 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
951 for (i=0; i < loopEnd; ++i){
952 arrLoc = ii + (i * clk[clkCnt]);
953 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
954 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
955 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
956 }else{ //error no peak detected
957 errCnt++;
958 }
959 }
960 //if we found no errors then we can stop here and a low clock (common clocks)
961 // this is correct one - return this clock
962 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
963 if(errCnt==0 && clkCnt<7) {
964 if (!clockFnd) *clock = clk[clkCnt];
965 return ii;
966 }
967 //if we found errors see if it is lowest so far and save it as best run
968 if(errCnt<bestErr[clkCnt]){
969 bestErr[clkCnt]=errCnt;
970 bestStart[clkCnt]=ii;
971 }
972 }
973 }
974 uint8_t iii;
975 uint8_t best=0;
976 for (iii=1; iii<clkEnd; ++iii){
977 if (bestErr[iii] < bestErr[best]){
978 if (bestErr[iii] == 0) bestErr[iii]=1;
979 // current best bit to error ratio vs new bit to error ratio
980 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
981 best = iii;
982 }
983 }
984 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]);
985 }
986 if (!clockFnd) *clock = clk[best];
987 return bestStart[best];
988 }
989
990 //by marshmellow
991 //detect psk clock by reading each phase shift
992 // a phase shift is determined by measuring the sample length of each wave
993 int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
994 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
995 uint16_t loopCnt = 4096; //don't need to loop through entire array...
996 if (size == 0) return 0;
997 if (size<loopCnt) loopCnt = size-20;
998
999 //if we already have a valid clock quit
1000 size_t i=1;
1001 for (; i < 8; ++i)
1002 if (clk[i] == clock) return clock;
1003
1004 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
1005 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
1006 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
1007 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
1008 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
1009 fc = countFC(dest, size, 0);
1010 if (fc!=2 && fc!=4 && fc!=8) return -1;
1011 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
1012
1013 //find first full wave
1014 for (i=160; i<loopCnt; i++){
1015 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1016 if (waveStart == 0) {
1017 waveStart = i+1;
1018 //prnt("DEBUG: waveStart: %d",waveStart);
1019 } else {
1020 waveEnd = i+1;
1021 //prnt("DEBUG: waveEnd: %d",waveEnd);
1022 waveLenCnt = waveEnd-waveStart;
1023 if (waveLenCnt > fc){
1024 firstFullWave = waveStart;
1025 fullWaveLen=waveLenCnt;
1026 break;
1027 }
1028 waveStart=0;
1029 }
1030 }
1031 }
1032 *firstPhaseShift = firstFullWave;
1033 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1034 //test each valid clock from greatest to smallest to see which lines up
1035 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1036 lastClkBit = firstFullWave; //set end of wave as clock align
1037 waveStart = 0;
1038 errCnt=0;
1039 peakcnt=0;
1040 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
1041
1042 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1043 //top edge of wave = start of new wave
1044 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1045 if (waveStart == 0) {
1046 waveStart = i+1;
1047 waveLenCnt=0;
1048 } else { //waveEnd
1049 waveEnd = i+1;
1050 waveLenCnt = waveEnd-waveStart;
1051 if (waveLenCnt > fc){
1052 //if this wave is a phase shift
1053 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);
1054 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1055 peakcnt++;
1056 lastClkBit+=clk[clkCnt];
1057 } else if (i<lastClkBit+8){
1058 //noise after a phase shift - ignore
1059 } else { //phase shift before supposed to based on clock
1060 errCnt++;
1061 }
1062 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1063 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1064 }
1065 waveStart=i+1;
1066 }
1067 }
1068 }
1069 if (errCnt == 0){
1070 return clk[clkCnt];
1071 }
1072 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1073 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1074 }
1075 //all tested with errors
1076 //return the highest clk with the most peaks found
1077 uint8_t best=7;
1078 for (i=7; i>=1; i--){
1079 if (peaksdet[i] > peaksdet[best]) {
1080 best = i;
1081 }
1082 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
1083 }
1084 return clk[best];
1085 }
1086
1087 int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
1088 int firstPhaseShift = 0;
1089 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
1090 }
1091
1092 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1093 //find shortest transition from high to low
1094 size_t i = 0;
1095 size_t transition1 = 0;
1096 int lowestTransition = 255;
1097 bool lastWasHigh = false;
1098
1099 //find first valid beginning of a high or low wave
1100 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1101 ++i;
1102 while ((dest[i] < peak && dest[i] > low) && (i < size))
1103 ++i;
1104 lastWasHigh = (dest[i] >= peak);
1105
1106 if (i==size) return 0;
1107 transition1 = i;
1108
1109 for (;i < size; i++) {
1110 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1111 lastWasHigh = (dest[i] >= peak);
1112 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1113 transition1 = i;
1114 }
1115 }
1116 if (lowestTransition == 255) lowestTransition = 0;
1117 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
1118 return lowestTransition;
1119 }
1120
1121 //by marshmellow
1122 //detect nrz clock by reading #peaks vs no peaks(or errors)
1123 int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
1124 size_t i=0;
1125 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1126 size_t loopCnt = 4096; //don't need to loop through entire array...
1127 if (size == 0) return 0;
1128 if (size<loopCnt) loopCnt = size-20;
1129 //if we already have a valid clock quit
1130 for (; i < 8; ++i)
1131 if (clk[i] == clock) return clock;
1132
1133 //get high and low peak
1134 int peak, low;
1135 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
1136
1137 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
1138 size_t ii;
1139 uint8_t clkCnt;
1140 uint8_t tol = 0;
1141 uint16_t smplCnt = 0;
1142 int16_t peakcnt = 0;
1143 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1144 uint16_t maxPeak = 255;
1145 bool firstpeak = false;
1146 //test for large clipped waves
1147 for (i=0; i<loopCnt; i++){
1148 if (dest[i] >= peak || dest[i] <= low){
1149 if (!firstpeak) continue;
1150 smplCnt++;
1151 } else {
1152 firstpeak=true;
1153 if (smplCnt > 6 ){
1154 if (maxPeak > smplCnt){
1155 maxPeak = smplCnt;
1156 //prnt("maxPk: %d",maxPeak);
1157 }
1158 peakcnt++;
1159 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1160 smplCnt=0;
1161 }
1162 }
1163 }
1164 bool errBitHigh = 0;
1165 bool bitHigh = 0;
1166 uint8_t ignoreCnt = 0;
1167 uint8_t ignoreWindow = 4;
1168 bool lastPeakHigh = 0;
1169 int lastBit = 0;
1170 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
1171 peakcnt=0;
1172 //test each valid clock from smallest to greatest to see which lines up
1173 for(clkCnt=0; clkCnt < 8; ++clkCnt){
1174 //ignore clocks smaller than smallest peak
1175 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
1176 //try lining up the peaks by moving starting point (try first 256)
1177 for (ii=20; ii < loopCnt; ++ii){
1178 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1179 peakcnt = 0;
1180 bitHigh = false;
1181 ignoreCnt = 0;
1182 lastBit = ii-clk[clkCnt];
1183 //loop through to see if this start location works
1184 for (i = ii; i < size-20; ++i) {
1185 //if we are at a clock bit
1186 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1187 //test high/low
1188 if (dest[i] >= peak || dest[i] <= low) {
1189 //if same peak don't count it
1190 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1191 peakcnt++;
1192 }
1193 lastPeakHigh = (dest[i] >= peak);
1194 bitHigh = true;
1195 errBitHigh = false;
1196 ignoreCnt = ignoreWindow;
1197 lastBit += clk[clkCnt];
1198 } else if (i == lastBit + clk[clkCnt] + tol) {
1199 lastBit += clk[clkCnt];
1200 }
1201 //else if not a clock bit and no peaks
1202 } else if (dest[i] < peak && dest[i] > low){
1203 if (ignoreCnt==0){
1204 bitHigh=false;
1205 if (errBitHigh==true) peakcnt--;
1206 errBitHigh=false;
1207 } else {
1208 ignoreCnt--;
1209 }
1210 // else if not a clock bit but we have a peak
1211 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1212 //error bar found no clock...
1213 errBitHigh=true;
1214 }
1215 }
1216 if(peakcnt>peaksdet[clkCnt]) {
1217 bestStart[clkCnt]=ii;
1218 peaksdet[clkCnt]=peakcnt;
1219 }
1220 }
1221 }
1222 }
1223 int iii=7;
1224 uint8_t best=0;
1225 for (iii=7; iii > 0; iii--){
1226 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1227 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
1228 best = iii;
1229 }
1230 } else if (peaksdet[iii] > peaksdet[best]){
1231 best = iii;
1232 }
1233 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);
1234 }
1235 *clockStartIdx = bestStart[best];
1236 return clk[best];
1237 }
1238
1239 int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
1240 size_t bestStart=0;
1241 return DetectNRZClock_ext(dest, size, clock, &bestStart);
1242 }
1243
1244 // by marshmellow
1245 // convert psk1 demod to psk2 demod
1246 // only transition waves are 1s
1247 void psk1TOpsk2(uint8_t *BitStream, size_t size)
1248 {
1249 size_t i=1;
1250 uint8_t lastBit=BitStream[0];
1251 for (; i<size; i++){
1252 if (BitStream[i]==7){
1253 //ignore errors
1254 } else if (lastBit!=BitStream[i]){
1255 lastBit=BitStream[i];
1256 BitStream[i]=1;
1257 } else {
1258 BitStream[i]=0;
1259 }
1260 }
1261 return;
1262 }
1263
1264 // by marshmellow
1265 // convert psk2 demod to psk1 demod
1266 // from only transition waves are 1s to phase shifts change bit
1267 void psk2TOpsk1(uint8_t *BitStream, size_t size)
1268 {
1269 uint8_t phase=0;
1270 for (size_t i=0; i<size; i++){
1271 if (BitStream[i]==1){
1272 phase ^=1;
1273 }
1274 BitStream[i]=phase;
1275 }
1276 return;
1277 }
1278
1279 // redesigned by marshmellow adjusted from existing decode functions
1280 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1281 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1282 {
1283 //26 bit 40134 format (don't know other formats)
1284 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};
1285 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};
1286 size_t startidx = 0;
1287 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1288 // if didn't find preamble try again inverting
1289 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1290 *invert ^= 1;
1291 }
1292 if (*size != 64 && *size != 224) return -2;
1293 if (*invert==1)
1294 for (size_t i = startidx; i < *size; i++)
1295 bitStream[i] ^= 1;
1296
1297 return (int) startidx;
1298 }
1299
1300 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1301 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1302 int nrzRawDemod_ext(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1303 if (justNoise(dest, *size)) return -1;
1304 *clk = DetectNRZClock(dest, *size, *clk);
1305 if (*clk==0) return -2;
1306 size_t i, gLen = 4096;
1307 if (gLen>*size) gLen = *size-20;
1308 int high, low;
1309 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1310
1311 uint8_t bit=0;
1312 //convert wave samples to 1's and 0's
1313 for(i=20; i < *size-20; i++){
1314 if (dest[i] >= high) bit = 1;
1315 if (dest[i] <= low) bit = 0;
1316 dest[i] = bit;
1317 }
1318 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1319 size_t lastBit = 0;
1320 size_t numBits = 0;
1321 for(i=21; i < *size-20; i++) {
1322 //if transition detected or large number of same bits - store the passed bits
1323 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1324 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1325 numBits += (i - lastBit + (*clk/4)) / *clk;
1326 if (lastBit == 0) {
1327 *startIdx = i - (numBits * *clk);
1328 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1329 }
1330 lastBit = i-1;
1331 }
1332 }
1333 *size = numBits;
1334 return 0;
1335 }
1336 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) {
1337 int startIdx = 0;
1338 return nrzRawDemod_ext(dest, size, clk, invert, &startIdx);
1339 }
1340
1341 //by marshmellow
1342 //detects the bit clock for FSK given the high and low Field Clocks
1343 uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
1344 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1345 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1346 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1347 uint8_t rfLensFnd = 0;
1348 uint8_t lastFCcnt = 0;
1349 uint16_t fcCounter = 0;
1350 uint16_t rfCounter = 0;
1351 uint8_t firstBitFnd = 0;
1352 size_t i;
1353 if (size == 0) return 0;
1354
1355 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1356 rfLensFnd=0;
1357 fcCounter=0;
1358 rfCounter=0;
1359 firstBitFnd=0;
1360 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
1361 // prime i to first peak / up transition
1362 for (i = 160; i < size-20; i++)
1363 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1364 break;
1365
1366 for (; i < size-20; i++){
1367 fcCounter++;
1368 rfCounter++;
1369
1370 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1371 continue;
1372 // else new peak
1373 // if we got less than the small fc + tolerance then set it to the small fc
1374 // if it is inbetween set it to the last counter
1375 if (fcCounter < fcHigh && fcCounter > fcLow)
1376 fcCounter = lastFCcnt;
1377 else if (fcCounter < fcLow+fcTol)
1378 fcCounter = fcLow;
1379 else //set it to the large fc
1380 fcCounter = fcHigh;
1381
1382 //look for bit clock (rf/xx)
1383 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1384 //not the same size as the last wave - start of new bit sequence
1385 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1386 for (int ii=0; ii<15; ii++){
1387 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
1388 rfCnts[ii]++;
1389 rfCounter = 0;
1390 break;
1391 }
1392 }
1393 if (rfCounter > 0 && rfLensFnd < 15){
1394 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1395 rfCnts[rfLensFnd]++;
1396 rfLens[rfLensFnd++] = rfCounter;
1397 }
1398 } else {
1399 *firstClockEdge = i;
1400 firstBitFnd++;
1401 }
1402 rfCounter=0;
1403 lastFCcnt=fcCounter;
1404 }
1405 fcCounter=0;
1406 }
1407 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1408
1409 for (i=0; i<15; i++){
1410 //get highest 2 RF values (might need to get more values to compare or compare all?)
1411 if (rfCnts[i]>rfCnts[rfHighest]){
1412 rfHighest3=rfHighest2;
1413 rfHighest2=rfHighest;
1414 rfHighest=i;
1415 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1416 rfHighest3=rfHighest2;
1417 rfHighest2=i;
1418 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1419 rfHighest3=i;
1420 }
1421 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
1422 }
1423 // set allowed clock remainder tolerance to be 1 large field clock length+1
1424 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1425 uint8_t tol1 = fcHigh+1;
1426
1427 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
1428
1429 // loop to find the highest clock that has a remainder less than the tolerance
1430 // compare samples counted divided by
1431 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1432 int ii=7;
1433 for (; ii>=2; ii--){
1434 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1435 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1436 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
1437 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
1438 break;
1439 }
1440 }
1441 }
1442 }
1443
1444 if (ii<2) return 0; // oops we went too far
1445
1446 return clk[ii];
1447 }
1448
1449 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
1450 int firstClockEdge = 0;
1451 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
1452 }
1453
1454 //by marshmellow
1455 //countFC is to detect the field clock lengths.
1456 //counts and returns the 2 most common wave lengths
1457 //mainly used for FSK field clock detection
1458 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
1459 {
1460 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1461 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1462 uint8_t fcLensFnd = 0;
1463 uint8_t lastFCcnt = 0;
1464 uint8_t fcCounter = 0;
1465 size_t i;
1466 if (size < 180) return 0;
1467
1468 // prime i to first up transition
1469 for (i = 160; i < size-20; i++)
1470 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1471 break;
1472
1473 for (; i < size-20; i++){
1474 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1475 // new up transition
1476 fcCounter++;
1477 if (fskAdj){
1478 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1479 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1480 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1481 if ((fcCounter==9) || fcCounter==4) fcCounter++;
1482 // save last field clock count (fc/xx)
1483 lastFCcnt = fcCounter;
1484 }
1485 // find which fcLens to save it to:
1486 for (int ii=0; ii<15; ii++){
1487 if (fcLens[ii]==fcCounter){
1488 fcCnts[ii]++;
1489 fcCounter=0;
1490 break;
1491 }
1492 }
1493 if (fcCounter>0 && fcLensFnd<15){
1494 //add new fc length
1495 fcCnts[fcLensFnd]++;
1496 fcLens[fcLensFnd++]=fcCounter;
1497 }
1498 fcCounter=0;
1499 } else {
1500 // count sample
1501 fcCounter++;
1502 }
1503 }
1504
1505 uint8_t best1=14, best2=14, best3=14;
1506 uint16_t maxCnt1=0;
1507 // go through fclens and find which ones are bigest 2
1508 for (i=0; i<15; i++){
1509 // get the 3 best FC values
1510 if (fcCnts[i]>maxCnt1) {
1511 best3=best2;
1512 best2=best1;
1513 maxCnt1=fcCnts[i];
1514 best1=i;
1515 } else if(fcCnts[i]>fcCnts[best2]){
1516 best3=best2;
1517 best2=i;
1518 } else if(fcCnts[i]>fcCnts[best3]){
1519 best3=i;
1520 }
1521 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]);
1522 }
1523 if (fcLens[best1]==0) return 0;
1524 uint8_t fcH=0, fcL=0;
1525 if (fcLens[best1]>fcLens[best2]){
1526 fcH=fcLens[best1];
1527 fcL=fcLens[best2];
1528 } else{
1529 fcH=fcLens[best2];
1530 fcL=fcLens[best1];
1531 }
1532 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1533 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]);
1534 return 0; //lots of waves not psk or fsk
1535 }
1536 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1537
1538 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
1539 if (fskAdj) return fcs;
1540 return fcLens[best1];
1541 }
1542
1543 //by marshmellow - demodulate PSK1 wave
1544 //uses wave lengths (# Samples)
1545 int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1546 if (size == 0) return -1;
1547 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1548 if (*size<loopCnt) loopCnt = *size;
1549
1550 size_t numBits=0;
1551 uint8_t curPhase = *invert;
1552 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1553 uint16_t fc=0, fullWaveLen=0, tol=1;
1554 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1555 fc = countFC(dest, *size, 1);
1556 uint8_t fc2 = fc >> 8;
1557 if (fc2 == 10) return -1; //fsk found - quit
1558 fc = fc & 0xFF;
1559 if (fc!=2 && fc!=4 && fc!=8) return -1;
1560 //PrintAndLog("DEBUG: FC: %d",fc);
1561 *clock = DetectPSKClock(dest, *size, *clock);
1562 if (*clock == 0) return -1;
1563
1564 //find start of modulating data in trace
1565 uint8_t threshold_value = 123; //-5
1566 i = findModStart(dest, *size, threshold_value, fc);
1567
1568 //find first phase shift
1569 int avgWaveVal=0, lastAvgWaveVal=0;
1570 waveStart = i;
1571 for (; i<loopCnt; i++) {
1572 // find peak
1573 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1574 waveEnd = i+1;
1575 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1576 waveLenCnt = waveEnd-waveStart;
1577 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1578 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1579 firstFullWave = waveStart;
1580 fullWaveLen=waveLenCnt;
1581 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1582 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
1583 break;
1584 }
1585
1586 waveStart = i+1;
1587 avgWaveVal = 0;
1588 }
1589 avgWaveVal += dest[i+2];
1590 }
1591 if (firstFullWave == 0) {
1592 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1593 // so skip a little to ensure we are past any Start Signal
1594 firstFullWave = 160;
1595 memset(dest, curPhase, firstFullWave / *clock);
1596 } else {
1597 memset(dest, curPhase^1, firstFullWave / *clock);
1598 }
1599 //advance bits
1600 numBits += (firstFullWave / *clock);
1601 *startIdx = firstFullWave - (*clock * numBits)+2;
1602 //set start of wave as clock align
1603 lastClkBit = firstFullWave;
1604 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1605 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1606 waveStart = 0;
1607 dest[numBits++] = curPhase; //set first read bit
1608 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1609 //top edge of wave = start of new wave
1610 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1611 if (waveStart == 0) {
1612 waveStart = i+1;
1613 waveLenCnt = 0;
1614 avgWaveVal = dest[i+1];
1615 } else { //waveEnd
1616 waveEnd = i+1;
1617 waveLenCnt = waveEnd-waveStart;
1618 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1619 if (waveLenCnt > fc){
1620 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1621 //this wave is a phase shift
1622 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1623 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1624 curPhase ^= 1;
1625 dest[numBits++] = curPhase;
1626 lastClkBit += *clock;
1627 } else if (i < lastClkBit+10+fc){
1628 //noise after a phase shift - ignore
1629 } else { //phase shift before supposed to based on clock
1630 errCnt++;
1631 dest[numBits++] = 7;
1632 }
1633 } else if (i+1 > lastClkBit + *clock + tol + fc){
1634 lastClkBit += *clock; //no phase shift but clock bit
1635 dest[numBits++] = curPhase;
1636 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1637 errCnt2++;
1638 if(errCnt2 > 101) return errCnt2;
1639 }
1640 avgWaveVal = 0;
1641 waveStart = i+1;
1642 }
1643 }
1644 avgWaveVal += dest[i+1];
1645 }
1646 *size = numBits;
1647 return errCnt;
1648 }
1649
1650 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1651 int startIdx = 0;
1652 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
1653 }
1654
1655 //by marshmellow
1656 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1657 bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
1658 size_t bufsize = *size;
1659 //need to loop through all samples and identify our clock, look for the ST pattern
1660 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1661 int clk = 0;
1662 int tol = 0;
1663 int i, j, skip, start, end, low, high, minClk, waveStart;
1664 bool complete = false;
1665 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1666 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
1667 size_t testsize = (bufsize < 512) ? bufsize : 512;
1668 int phaseoff = 0;
1669 high = low = 128;
1670 memset(tmpbuff, 0, sizeof(tmpbuff));
1671
1672 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1673 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1674 return false; //just noise
1675 }
1676 i = 0;
1677 j = 0;
1678 minClk = 255;
1679 // get to first full low to prime loop and skip incomplete first pulse
1680 while ((buffer[i] < high) && (i < bufsize))
1681 ++i;
1682 while ((buffer[i] > low) && (i < bufsize))
1683 ++i;
1684 skip = i;
1685
1686 // populate tmpbuff buffer with pulse lengths
1687 while (i < bufsize) {
1688 // measure from low to low
1689 while ((buffer[i] > low) && (i < bufsize))
1690 ++i;
1691 start= i;
1692 while ((buffer[i] < high) && (i < bufsize))
1693 ++i;
1694 //first high point for this wave
1695 waveStart = i;
1696 while ((buffer[i] > low) && (i < bufsize))
1697 ++i;
1698 if (j >= (bufsize/32)) {
1699 break;
1700 }
1701 waveLen[j] = i - waveStart; //first high to first low
1702 tmpbuff[j++] = i - start;
1703 if (i-start < minClk && i < bufsize) {
1704 minClk = i - start;
1705 }
1706 }
1707 // set clock - might be able to get this externally and remove this work...
1708 if (!clk) {
1709 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1710 tol = fndClk[clkCnt]/8;
1711 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1712 clk=fndClk[clkCnt];
1713 break;
1714 }
1715 }
1716 // clock not found - ERROR
1717 if (!clk) {
1718 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1719 return false;
1720 }
1721 } else tol = clk/8;
1722
1723 *foundclock = clk;
1724
1725 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1726 start = -1;
1727 for (i = 0; i < j - 4; ++i) {
1728 skip += tmpbuff[i];
1729 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1730 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
1731 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
1732 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1733 start = i + 3;
1734 break;
1735 }
1736 }
1737 }
1738 }
1739 }
1740 // first ST not found - ERROR
1741 if (start < 0) {
1742 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1743 return false;
1744 } else {
1745 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
1746 }
1747 if (waveLen[i+2] > clk*1+tol)
1748 phaseoff = 0;
1749 else
1750 phaseoff = clk/2;
1751
1752 // skip over the remainder of ST
1753 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1754
1755 // now do it again to find the end
1756 end = skip;
1757 for (i += 3; i < j - 4; ++i) {
1758 end += tmpbuff[i];
1759 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1760 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
1761 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
1762 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1763 complete = true;
1764 break;
1765 }
1766 }
1767 }
1768 }
1769 }
1770 end -= phaseoff;
1771 //didn't find second ST - ERROR
1772 if (!complete) {
1773 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1774 return false;
1775 }
1776 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);
1777 //now begin to trim out ST so we can use normal demod cmds
1778 start = skip;
1779 size_t datalen = end - start;
1780 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1781 if ( clk - (datalen % clk) <= clk/8) {
1782 // padd the amount off - could be problematic... but shouldn't happen often
1783 datalen += clk - (datalen % clk);
1784 } else if ( (datalen % clk) <= clk/8 ) {
1785 // padd the amount off - could be problematic... but shouldn't happen often
1786 datalen -= datalen % clk;
1787 } else {
1788 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1789 return false;
1790 }
1791 // if datalen is less than one t55xx block - ERROR
1792 if (datalen/clk < 8*4) {
1793 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1794 return false;
1795 }
1796 size_t dataloc = start;
1797 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1798 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1799 for ( i=0; i <= (clk/8); ++i ) {
1800 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1801 dataloc -= i;
1802 break;
1803 }
1804 }
1805 }
1806
1807 size_t newloc = 0;
1808 i=0;
1809 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1810 bool firstrun = true;
1811 // warning - overwriting buffer given with raw wave data with ST removed...
1812 while ( dataloc < bufsize-(clk/2) ) {
1813 //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)
1814 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1815 for(i=0; i < clk/2-tol; ++i) {
1816 buffer[dataloc+i] = high+5;
1817 }
1818 } //test for single sample outlier (high between two lows) in the case of very strong waves
1819 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1820 buffer[dataloc] = buffer[dataloc+2];
1821 buffer[dataloc+1] = buffer[dataloc+2];
1822 }
1823 if (firstrun) {
1824 *stend = dataloc;
1825 *ststart = dataloc-(clk*4);
1826 firstrun=false;
1827 }
1828 for (i=0; i<datalen; ++i) {
1829 if (i+newloc < bufsize) {
1830 if (i+newloc < dataloc)
1831 buffer[i+newloc] = buffer[dataloc];
1832
1833 dataloc++;
1834 }
1835 }
1836 newloc += i;
1837 //skip next ST - we just assume it will be there from now on...
1838 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1839 dataloc += clk*4;
1840 }
1841 *size = newloc;
1842 return true;
1843 }
1844
1845 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1846 size_t ststart = 0, stend = 0;
1847 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1848 }
1849
1850 // by iceman
1851 // find Visa2000 preamble in already demoded data
1852 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1853 if (*size < 96) return -1; //make sure buffer has data
1854 size_t startIdx = 0;
1855 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};
1856 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1857 return -2; //preamble not found
1858 if (*size != 96) return -3; //wrong demoded size
1859 //return start position
1860 return (int)startIdx;
1861 }
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