]> git.zerfleddert.de Git - proxmark3-svn/blob - common/lfdemod.c
FIX: @marshmellow42 's ST detection fix.
[proxmark3-svn] / common / lfdemod.c
1 //-----------------------------------------------------------------------------
2 // Copyright (C) 2014
3 //
4 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
5 // at your option, any later version. See the LICENSE.txt file for the text of
6 // the license.
7 //-----------------------------------------------------------------------------
8 // Low frequency demod/decode commands
9 //-----------------------------------------------------------------------------
10 #include "lfdemod.h"
11
12 //un_comment to allow debug print calls when used not on device
13 void dummy(char *fmt, ...){}
14
15
16 #ifndef ON_DEVICE
17 # include "ui.h"
18 # include "cmdparser.h"
19 # include "cmddata.h"
20 # define prnt PrintAndLog
21 #else
22 uint8_t g_debugMode=0;
23 # define prnt dummy
24 #endif
25
26 //test samples are not just noise
27 uint8_t justNoise(uint8_t *bits, size_t size) {
28 #define THRESHOLD 123
29 uint8_t val = 1;
30 for(size_t idx=0; idx < size && val ;idx++)
31 val = bits[idx] < THRESHOLD;
32 return val;
33 }
34
35 //by marshmellow
36 //get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
37 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
38 {
39 *high=0;
40 *low=255;
41 // get high and low thresholds
42 for (size_t i=0; i < size; i++){
43 if (BitStream[i] > *high) *high = BitStream[i];
44 if (BitStream[i] < *low) *low = BitStream[i];
45 }
46 if (*high < 123) return -1; // just noise
47 *high = ((*high-128)*fuzzHi + 12800)/100;
48 *low = ((*low-128)*fuzzLo + 12800)/100;
49 return 1;
50 }
51
52 // by marshmellow
53 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
54 // returns 1 if passed
55 uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
56 {
57 uint8_t ans = 0;
58 for (uint8_t i = 0; i < bitLen; i++){
59 ans ^= ((bits >> i) & 1);
60 }
61 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
62 return (ans == pType);
63 }
64
65 //by marshmellow
66 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
67 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
68 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
69 {
70 uint32_t parityWd = 0;
71 size_t j = 0, bitCnt = 0;
72 for (int word = 0; word < (bLen); word += pLen){
73 for (int bit=0; bit < pLen; bit++){
74 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
75 BitStream[j++] = (BitStream[startIdx+word+bit]);
76 }
77 if (word+pLen > bLen) break;
78
79 j--; // overwrite parity with next data
80 // if parity fails then return 0
81 switch (pType) {
82 case 3: if (BitStream[j]==1) { return 0; } break; //should be 0 spacer bit
83 case 2: if (BitStream[j]==0) { return 0; } break; //should be 1 spacer bit
84 default: if (parityTest(parityWd, pLen, pType) == 0) { return 0; } break; //test parity
85 }
86 bitCnt += (pLen-1);
87 parityWd = 0;
88 }
89 // if we got here then all the parities passed
90 //return ID start index and size
91 return bitCnt;
92 }
93
94 // by marshmellow
95 // takes a array of binary values, length of bits per parity (includes parity bit),
96 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
97 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
98 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
99 {
100 uint32_t parityWd = 0;
101 size_t j = 0, bitCnt = 0;
102 for (int word = 0; word < sourceLen; word+=pLen-1) {
103 for (int bit=0; bit < pLen-1; bit++){
104 parityWd = (parityWd << 1) | BitSource[word+bit];
105 dest[j++] = (BitSource[word+bit]);
106 }
107
108 // if parity fails then return 0
109 switch (pType) {
110 case 3: dest[j++]=0; break; // marker bit which should be a 0
111 case 2: dest[j++]=1; break; // marker bit which should be a 1
112 default:
113 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
114 break;
115 }
116 bitCnt += pLen;
117 parityWd = 0;
118 }
119 // if we got here then all the parities passed
120 //return ID start index and size
121 return bitCnt;
122 }
123
124 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
125 {
126 uint32_t num = 0;
127 for(int i = 0 ; i < numbits ; i++) {
128 num = (num << 1) | (*src);
129 src++;
130 }
131 return num;
132 }
133
134 //least significant bit first
135 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
136 {
137 uint32_t num = 0;
138 for(int i = 0 ; i < numbits ; i++) {
139 num = (num << 1) | *(src + (numbits-(i+1)));
140 }
141 return num;
142 }
143
144 //by marshmellow
145 // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
146 bool preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx){
147 return preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false);
148 }
149 //by marshmellow
150 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
151 // param @findone: look for a repeating preamble or only the first.
152 // em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
153 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone)
154 {
155 // Sanity check. If preamble length is bigger than bitstream length.
156 if ( *size <= pLen ) return false;
157
158 uint8_t foundCnt = 0;
159 for (int idx = 0; idx < *size - pLen; idx++){
160 if (memcmp(BitStream+idx, preamble, pLen) == 0){
161 if (g_debugMode) prnt("DEBUG: preamble found at %i", idx);
162 //first index found
163 foundCnt++;
164 if (foundCnt == 1){
165 *startIdx = idx;
166 if (findone) return true;
167 }
168 if (foundCnt == 2){
169 *size = idx - *startIdx;
170 return true;
171 }
172 }
173 }
174 return false;
175 }
176
177 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
178 size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
179 size_t i = 0;
180 size_t waveSizeCnt = 0;
181 uint8_t thresholdCnt = 0;
182 bool isAboveThreshold = dest[i++] >= threshold_value;
183 for (; i < size-20; i++ ) {
184 if(dest[i] < threshold_value && isAboveThreshold) {
185 thresholdCnt++;
186 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
187 isAboveThreshold = false;
188 waveSizeCnt = 0;
189 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
190 thresholdCnt++;
191 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
192 isAboveThreshold = true;
193 waveSizeCnt = 0;
194 } else {
195 waveSizeCnt++;
196 }
197 if (thresholdCnt > 10) break;
198 }
199 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
200 return i;
201 }
202
203 //by marshmellow
204 //takes 1s and 0s and searches for EM410x format - output EM ID
205 // actually, no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
206 int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
207 {
208 // sanity check
209 if (BitStream[1] > 1) return -1;
210
211 uint8_t fmtlen;
212 *startIdx = 0;
213
214 // preamble 0111111111
215 // include 0 in front to help get start pos
216 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
217 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
218 return -2;
219 if (*size < 64) return -3;
220
221 fmtlen = (*size == 110) ? 22 : 10;
222
223 //skip last 4bit parity row for simplicity
224 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);
225
226 switch (*size) {
227 case 40: {
228 // std em410x format
229 *hi = 0;
230 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
231 break;
232 }
233 case 88: {
234 // long em format
235 *hi = (bytebits_to_byte(BitStream, 24));
236 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
237 break;
238 }
239 default: return -4;
240 }
241 return 1;
242 }
243
244 //by marshmellow
245 //demodulates strong heavily clipped samples
246 //RETURN: num of errors. if 0, is ok.
247 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
248 {
249 size_t bitCnt=0, smplCnt=0, errCnt=0;
250 uint8_t waveHigh = 0;
251 for (size_t i=0; i < *size; i++){
252 if (BinStream[i] >= high && waveHigh){
253 smplCnt++;
254 } else if (BinStream[i] <= low && !waveHigh){
255 smplCnt++;
256 } else { //transition
257 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
258
259 if (smplCnt > clk-(clk/4)-1) { //full clock
260 if (smplCnt > clk + (clk/4)+1) { //too many samples
261 errCnt++;
262 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
263 BinStream[bitCnt++] = 7;
264 } else if (waveHigh) {
265 BinStream[bitCnt++] = invert;
266 BinStream[bitCnt++] = invert;
267 } else if (!waveHigh) {
268 BinStream[bitCnt++] = invert ^ 1;
269 BinStream[bitCnt++] = invert ^ 1;
270 }
271 waveHigh ^= 1;
272 smplCnt = 0;
273 } else if (smplCnt > (clk/2) - (clk/4)-1) {
274 if (waveHigh) {
275 BinStream[bitCnt++] = invert;
276 } else if (!waveHigh) {
277 BinStream[bitCnt++] = invert ^ 1;
278 }
279 waveHigh ^= 1;
280 smplCnt = 0;
281 } else if (!bitCnt) {
282 //first bit
283 waveHigh = (BinStream[i] >= high);
284 smplCnt = 1;
285 } else {
286 smplCnt++;
287 //transition bit oops
288 }
289 } else { //haven't hit new high or new low yet
290 smplCnt++;
291 }
292 }
293 }
294 *size = bitCnt;
295 return errCnt;
296 }
297
298 //by marshmellow
299 void askAmp(uint8_t *BitStream, size_t size)
300 {
301 uint8_t last = 128;
302 for(size_t i = 1; i < size; ++i){
303 if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
304 last = 255;
305 else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
306 last = 0;
307
308 BitStream[i] = last;
309 }
310 }
311
312 //by marshmellow
313 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
314 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
315 {
316 if (*size==0) return -1;
317 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
318
319 if (*clk==0 || start < 0) return -3;
320 if (*invert != 1) *invert = 0;
321 if (amp==1) askAmp(BinStream, *size);
322 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
323
324 uint8_t initLoopMax = 255;
325 if (initLoopMax > *size) initLoopMax = *size;
326 // Detect high and lows
327 //25% clip in case highs and lows aren't clipped [marshmellow]
328 int high, low;
329 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
330 return -2; //just noise
331
332 size_t errCnt = 0;
333 // if clean clipped waves detected run alternate demod
334 if (DetectCleanAskWave(BinStream, *size, high, low)) {
335 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
336 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
337 if (askType) //askman
338 return manrawdecode(BinStream, size, 0);
339 //askraw
340 return errCnt;
341 }
342 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
343
344 int lastBit; //set first clock check - can go negative
345 size_t i, bitnum = 0; //output counter
346 uint8_t midBit = 0;
347 uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
348 if (*clk <= 32) tol = 1; //clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
349 size_t MaxBits = 3072; //max bits to collect
350 lastBit = start - *clk;
351
352 for (i = start; i < *size; ++i) {
353 if (i-lastBit >= *clk-tol){
354 if (BinStream[i] >= high) {
355 BinStream[bitnum++] = *invert;
356 } else if (BinStream[i] <= low) {
357 BinStream[bitnum++] = *invert ^ 1;
358 } else if (i-lastBit >= *clk+tol) {
359 if (bitnum > 0) {
360 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
361 BinStream[bitnum++]=7;
362 errCnt++;
363 }
364 } else { //in tolerance - looking for peak
365 continue;
366 }
367 midBit = 0;
368 lastBit += *clk;
369 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
370 if (BinStream[i] >= high) {
371 BinStream[bitnum++] = *invert;
372 } else if (BinStream[i] <= low) {
373 BinStream[bitnum++] = *invert ^ 1;
374 } else if (i-lastBit >= *clk/2+tol) {
375 BinStream[bitnum] = BinStream[bitnum-1];
376 bitnum++;
377 } else { //in tolerance - looking for peak
378 continue;
379 }
380 midBit = 1;
381 }
382 if (bitnum >= MaxBits) break;
383 }
384 *size = bitnum;
385 return errCnt;
386 }
387 //by marshmellow
388 //take 10 and 01 and manchester decode
389 //run through 2 times and take least errCnt
390 int manrawdecode(uint8_t *BitStream, size_t *size, uint8_t invert){
391
392 // sanity check
393 if (*size < 16) return -1;
394
395 int errCnt = 0, bestErr = 1000;
396 uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;
397 size_t i, k;
398
399 //find correct start position [alignment]
400 for (k = 0; k < 2; ++k){
401 for (i = k; i < *size-3; i += 2) {
402 if (BitStream[i] == BitStream[i+1])
403 errCnt++;
404 }
405 if (bestErr > errCnt){
406 bestErr = errCnt;
407 bestRun = k;
408 }
409 errCnt = 0;
410 }
411
412 //decode
413 for (i = bestRun; i < *size-3; i += 2){
414 if (BitStream[i] == 1 && (BitStream[i+1] == 0)){
415 BitStream[bitnum++] = invert;
416 } else if ((BitStream[i] == 0) && BitStream[i+1] == 1){
417 BitStream[bitnum++] = invert^1;
418 } else {
419 BitStream[bitnum++] = 7;
420 }
421 if (bitnum > MaxBits) break;
422 }
423 *size = bitnum;
424 return bestErr;
425 }
426
427 uint32_t manchesterEncode2Bytes(uint16_t datain) {
428 uint32_t output = 0;
429 uint8_t curBit = 0;
430 for (uint8_t i=0; i<16; i++) {
431 curBit = (datain >> (15-i) & 1);
432 output |= (1<<(((15-i)*2)+curBit));
433 }
434 return output;
435 }
436
437 //by marshmellow
438 //encode binary data into binary manchester
439 int ManchesterEncode(uint8_t *BitStream, size_t size)
440 {
441 size_t modIdx=20000, i=0;
442 if (size>modIdx) return -1;
443 for (size_t idx=0; idx < size; idx++){
444 BitStream[idx+modIdx++] = BitStream[idx];
445 BitStream[idx+modIdx++] = BitStream[idx]^1;
446 }
447 for (; i<(size*2); i++){
448 BitStream[i] = BitStream[i+20000];
449 }
450 return i;
451 }
452
453 //by marshmellow
454 //take 01 or 10 = 1 and 11 or 00 = 0
455 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
456 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
457 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
458 {
459 uint16_t bitnum = 0;
460 uint16_t errCnt = 0;
461 size_t i = offset;
462 uint16_t MaxBits=512;
463 //if not enough samples - error
464 if (*size < 51) return -1;
465 //check for phase change faults - skip one sample if faulty
466 uint8_t offsetA = 1, offsetB = 1;
467 for (; i<48; i+=2){
468 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
469 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
470 }
471 if (!offsetA && offsetB) offset++;
472 for (i=offset; i<*size-3; i+=2){
473 //check for phase error
474 if (BitStream[i+1]==BitStream[i+2]) {
475 BitStream[bitnum++]=7;
476 errCnt++;
477 }
478 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
479 BitStream[bitnum++]=1^invert;
480 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
481 BitStream[bitnum++]=invert;
482 } else {
483 BitStream[bitnum++]=7;
484 errCnt++;
485 }
486 if(bitnum>MaxBits) break;
487 }
488 *size=bitnum;
489 return errCnt;
490 }
491
492 // by marshmellow
493 // demod gProxIIDemod
494 // error returns as -x
495 // success returns start position in BitStream
496 // BitStream must contain previously askrawdemod and biphasedemoded data
497 int gProxII_Demod(uint8_t BitStream[], size_t *size)
498 {
499 size_t startIdx=0;
500 uint8_t preamble[] = {1,1,1,1,1,0};
501
502 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx))
503 return -3; //preamble not found
504
505 if (*size != 96) return -2; //should have found 96 bits
506
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)
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
533 // Need to threshold first sample
534 if(dest[idx] < threshold_value) dest[0] = 0;
535 else dest[0] = 1;
536 idx++;
537
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-20; idx++) {
544 // threshold current value
545
546 if (dest[idx] < threshold_value) dest[idx] = 0;
547 else dest[idx] = 1;
548
549 // Check for 0->1 transition
550 if (dest[idx-1] < dest[idx]) {
551 preLastSample = LastSample;
552 LastSample = currSample;
553 currSample = idx-last_transition;
554 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
555 //do nothing with extra garbage
556 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
557 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
558 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
559 dest[numBits-1]=1;
560 }
561 dest[numBits++]=1;
562
563 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
564 //do nothing with beginning garbage and reset.. should be rare..
565 numBits = 0;
566 } 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)
567 dest[numBits++]=1;
568 } else { //9+ = 10 sample waves (or 6+ = 7)
569 dest[numBits++]=0;
570 }
571 last_transition = idx;
572 }
573 }
574 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
575 }
576
577 //translate 11111100000 to 10
578 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
579 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
580 uint8_t invert, uint8_t fchigh, uint8_t fclow)
581 {
582 uint8_t lastval=dest[0];
583 size_t idx=0;
584 size_t numBits=0;
585 uint32_t n=1;
586 for( idx=1; idx < size; idx++) {
587 n++;
588 if (dest[idx]==lastval) continue; //skip until we hit a transition
589
590 //find out how many bits (n) we collected
591 //if lastval was 1, we have a 1->0 crossing
592 if (dest[idx-1]==1) {
593 n = (n * fclow + rfLen/2) / rfLen;
594 } else {// 0->1 crossing
595 n = (n * fchigh + rfLen/2) / rfLen;
596 }
597 if (n == 0) n = 1;
598
599 //add to our destination the bits we collected
600 memset(dest+numBits, dest[idx-1]^invert , n);
601 numBits += n;
602 n=0;
603 lastval=dest[idx];
604 }//end for
605 // if valid extra bits at the end were all the same frequency - add them in
606 if (n > rfLen/fchigh) {
607 if (dest[idx-2]==1) {
608 n = (n * fclow + rfLen/2) / rfLen;
609 } else {
610 n = (n * fchigh + rfLen/2) / rfLen;
611 }
612 memset(dest+numBits, dest[idx-1]^invert , n);
613 numBits += n;
614 }
615 return numBits;
616 }
617
618 //by marshmellow (from holiman's base)
619 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
620 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
621 {
622 // FSK demodulator
623 size = fsk_wave_demod(dest, size, fchigh, fclow);
624 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
625 return size;
626 }
627
628 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
629 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
630 {
631 if (justNoise(dest, *size)) return -1;
632
633 size_t numStart=0, size2 = *size, startIdx=0;
634 // FSK demodulator
635 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
636 if (*size < 96*2) return -2;
637 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
638 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
639 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
640 return -3; //preamble not found
641
642 numStart = startIdx + sizeof(preamble);
643 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
644 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
645 if (dest[idx] == dest[idx+1]){
646 return -4; //not manchester data
647 }
648 *hi2 = (*hi2<<1)|(*hi>>31);
649 *hi = (*hi<<1)|(*lo>>31);
650 //Then, shift in a 0 or one into low
651 *lo <<= 1;
652 if (dest[idx] && !dest[idx+1]) // 1 0
653 *lo |= 1;
654 else // 0 1
655 *lo |= 0;
656 }
657 return (int)startIdx;
658 }
659
660 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
661 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
662 {
663 if (justNoise(dest, *size)) return -1;
664
665 size_t numStart=0, size2 = *size, startIdx=0;
666 // FSK demodulator
667 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
668 if (*size < 96) return -2;
669
670 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
671 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
672 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
673 return -3; //preamble not found
674
675 numStart = startIdx + sizeof(preamble);
676 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
677 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
678 if (dest[idx] == dest[idx+1])
679 return -4; //not manchester data
680 *hi2 = (*hi2<<1)|(*hi>>31);
681 *hi = (*hi<<1)|(*lo>>31);
682 //Then, shift in a 0 or one into low
683 if (dest[idx] && !dest[idx+1]) // 1 0
684 *lo=(*lo<<1)|1;
685 else // 0 1
686 *lo=(*lo<<1)|0;
687 }
688 return (int)startIdx;
689 }
690
691 int IOdemodFSK(uint8_t *dest, size_t size)
692 {
693 if (justNoise(dest, size)) return -1;
694 //make sure buffer has data
695 if (size < 66*64) return -2;
696 // FSK demodulator
697 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
698 if (size < 65) return -3; //did we get a good demod?
699 //Index map
700 //0 10 20 30 40 50 60
701 //| | | | | | |
702 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
703 //-----------------------------------------------------------------------------
704 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
705 //
706 //XSF(version)facility:codeone+codetwo
707 //Handle the data
708 size_t startIdx = 0;
709 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
710 if (! preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx))
711 return -4; //preamble not found
712
713 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
714 //confirmed proper separator bits found
715 //return start position
716 return (int) startIdx;
717 }
718 return -5;
719 }
720
721 // by marshmellow
722 // find viking preamble 0xF200 in already demoded data
723 int VikingDemod_AM(uint8_t *dest, size_t *size) {
724 //make sure buffer has data
725 if (*size < 64*2) return -2;
726 size_t startIdx = 0;
727 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};
728 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
729 return -4; //preamble not found
730
731 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^
732 bytebits_to_byte(dest+startIdx+8,8) ^
733 bytebits_to_byte(dest+startIdx+16,8) ^
734 bytebits_to_byte(dest+startIdx+24,8) ^
735 bytebits_to_byte(dest+startIdx+32,8) ^
736 bytebits_to_byte(dest+startIdx+40,8) ^
737 bytebits_to_byte(dest+startIdx+48,8) ^
738 bytebits_to_byte(dest+startIdx+56,8);
739 if ( checkCalc != 0xA8 ) return -5;
740 if (*size != 64) return -6;
741 //return start position
742 return (int)startIdx;
743 }
744
745 // by iceman
746 // find Visa2000 preamble in already demoded data
747 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
748 if (*size < 96) return -1; //make sure buffer has data
749 size_t startIdx = 0;
750 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};
751 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
752 return -2; //preamble not found
753 if (*size != 96) return -3; //wrong demoded size
754 //return start position
755 return (int)startIdx;
756 }
757 // by iceman
758 // find Noralsy preamble in already demoded data
759 int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
760 if (*size < 96) return -1; //make sure buffer has data
761 size_t startIdx = 0;
762 uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};
763 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
764 return -2; //preamble not found
765 if (*size != 96) return -3; //wrong demoded size
766 //return start position
767 return (int)startIdx;
768 }
769 // find presco preamble 0x10D in already demoded data
770 int PrescoDemod(uint8_t *dest, size_t *size) {
771 if (*size < 128*2) return -1; //make sure buffer has data
772 size_t startIdx = 0;
773 uint8_t preamble[] = {0,0,0,1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
774 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
775 return -2; //preamble not found
776 if (*size != 128) return -3; //wrong demoded size
777 //return start position
778 return (int)startIdx;
779 }
780
781 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
782 // BitStream must contain previously askrawdemod and biphasedemoded data
783 int FDXBdemodBI(uint8_t *dest, size_t *size) {
784 if (*size < 128*2) return -1; //make sure buffer has enough data
785 size_t startIdx = 0;
786 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
787 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
788 return -2; //preamble not found
789 if (*size != 128) return -3; //wrong demoded size
790 //return start position
791 return (int)startIdx;
792 }
793
794 // ASK/Diphase fc/64 (inverted Biphase)
795 // Note: this i s not a demod, this is only a detection
796 // the parameter *dest needs to be demoded before call
797 // 0xFFFF preamble, 64bits
798 int JablotronDemod(uint8_t *dest, size_t *size){
799 if (*size < 64*2) return -1; //make sure buffer has enough data
800 size_t startIdx = 0;
801 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
802 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
803 return -2; //preamble not found
804 if (*size != 64) return -3; // wrong demoded size
805
806 uint8_t checkchksum = 0;
807 for (int i=16; i < 56; i += 8) {
808 checkchksum += bytebits_to_byte(dest+startIdx+i,8);
809 }
810 checkchksum ^= 0x3A;
811 uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
812 if ( checkchksum != crc ) return -5;
813 return (int)startIdx;
814 }
815
816 // by marshmellow
817 // FSK Demod then try to locate an AWID ID
818 int AWIDdemodFSK(uint8_t *dest, size_t *size)
819 {
820 //make sure buffer has enough data
821 if (*size < 96*50) return -1;
822
823 if (justNoise(dest, *size)) return -2;
824
825 // FSK demodulator
826 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
827 if (*size < 96) return -3; //did we get a good demod?
828
829 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
830 size_t startIdx = 0;
831 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
832 return -4; //preamble not found
833 if (*size != 96) return -5;
834 return (int)startIdx;
835 }
836
837 // by marshmellow
838 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
839 int PyramiddemodFSK(uint8_t *dest, size_t *size)
840 {
841 //make sure buffer has data
842 if (*size < 128*50) return -5;
843
844 //test samples are not just noise
845 if (justNoise(dest, *size)) return -1;
846
847 // FSK demodulator
848 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
849 if (*size < 128) return -2; //did we get a good demod?
850 size_t startIdx = 0;
851 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1};
852 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
853 return -4; //preamble not found
854 if (*size != 128) return -3;
855 return (int)startIdx;
856 }
857
858 // find nedap preamble in already demoded data
859 int NedapDemod(uint8_t *dest, size_t *size) {
860 //make sure buffer has data
861 if (*size < 128) return -3;
862
863 size_t startIdx = 0;
864 //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
865 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
866 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
867 return -4; //preamble not found
868 return (int) startIdx;
869 }
870
871 // Find IDTEC PSK1, RF Preamble == 0x4944544B, Demodsize 64bits
872 // by iceman
873 int IdteckDemodPSK(uint8_t *dest, size_t *size) {
874 //make sure buffer has data
875 if (*size < 64*2) return -1;
876 size_t startIdx = 0;
877 uint8_t preamble[] = {0,1,0,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,1,0,1,1};
878 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
879 return -2; //preamble not found
880 if (*size != 64) return -3; // wrong demoded size
881 return (int) startIdx;
882 }
883
884 // by marshmellow
885 // to detect a wave that has heavily clipped (clean) samples
886 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
887 {
888 bool allArePeaks = true;
889 uint16_t cntPeaks=0;
890 size_t loopEnd = 512+160;
891 if (loopEnd > size) loopEnd = size;
892 for (size_t i=160; i<loopEnd; i++){
893 if (dest[i]>low && dest[i]<high)
894 allArePeaks = false;
895 else
896 cntPeaks++;
897 }
898 if (!allArePeaks){
899 if (cntPeaks > 300) return true;
900 }
901 return allArePeaks;
902 }
903 // by marshmellow
904 // to help detect clocks on heavily clipped samples
905 // based on count of low to low
906 int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
907 {
908 uint8_t fndClk[] = {8,16,32,40,50,64,128};
909 size_t startwave;
910 size_t i = 100;
911 size_t minClk = 255;
912 // get to first full low to prime loop and skip incomplete first pulse
913 while ((dest[i] < high) && (i < size))
914 ++i;
915 while ((dest[i] > low) && (i < size))
916 ++i;
917
918 // loop through all samples
919 while (i < size) {
920 // measure from low to low
921 while ((dest[i] > low) && (i < size))
922 ++i;
923 startwave= i;
924 while ((dest[i] < high) && (i < size))
925 ++i;
926 while ((dest[i] > low) && (i < size))
927 ++i;
928 //get minimum measured distance
929 if (i-startwave < minClk && i < size)
930 minClk = i - startwave;
931 }
932 // set clock
933 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
934 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
935 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
936 return fndClk[clkCnt];
937 }
938 return 0;
939 }
940
941 // by marshmellow
942 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
943 // maybe somehow adjust peak trimming value based on samples to fix?
944 // return start index of best starting position for that clock and return clock (by reference)
945 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
946 {
947 size_t i=1;
948 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
949 uint8_t clkEnd = 9;
950 uint8_t loopCnt = 255; //don't need to loop through entire array...
951 if (size <= loopCnt+60) return -1; //not enough samples
952 size -= 60; //sometimes there is a strange end wave - filter out this....
953 //if we already have a valid clock
954 uint8_t clockFnd=0;
955 for (;i<clkEnd;++i)
956 if (clk[i] == *clock) clockFnd = i;
957 //clock found but continue to find best startpos
958
959 //get high and low peak
960 int peak, low;
961 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
962
963 //test for large clean peaks
964 if (!clockFnd){
965 if (DetectCleanAskWave(dest, size, peak, low)==1){
966 int ans = DetectStrongAskClock(dest, size, peak, low);
967 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
968 for (i=clkEnd-1; i>0; i--){
969 if (clk[i] == ans) {
970 *clock = ans;
971 //clockFnd = i;
972 return 0; // for strong waves i don't use the 'best start position' yet...
973 //break; //clock found but continue to find best startpos [not yet]
974 }
975 }
976 }
977 }
978 uint8_t ii;
979 uint8_t clkCnt, tol = 0;
980 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
981 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
982 size_t errCnt = 0;
983 size_t arrLoc, loopEnd;
984
985 if (clockFnd>0) {
986 clkCnt = clockFnd;
987 clkEnd = clockFnd+1;
988 } else {
989 clkCnt=1;
990 }
991
992 //test each valid clock from smallest to greatest to see which lines up
993 for(; clkCnt < clkEnd; clkCnt++) {
994 if (clk[clkCnt] <= 32) {
995 tol=1;
996 } else {
997 tol=0;
998 }
999 //if no errors allowed - keep start within the first clock
1000 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128)
1001 loopCnt = clk[clkCnt] * 2;
1002
1003 bestErr[clkCnt] = 1000;
1004
1005 //try lining up the peaks by moving starting point (try first few clocks)
1006 for (ii=0; ii < loopCnt; ii++){
1007 if (dest[ii] < peak && dest[ii] > low) continue;
1008
1009 errCnt = 0;
1010 // now that we have the first one lined up test rest of wave array
1011 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
1012 for (i=0; i < loopEnd; ++i){
1013 arrLoc = ii + (i * clk[clkCnt]);
1014 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
1015 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
1016 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
1017 }else{ //error no peak detected
1018 errCnt++;
1019 }
1020 }
1021 //if we found no errors then we can stop here and a low clock (common clocks)
1022 // this is correct one - return this clock
1023 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
1024 if (errCnt==0 && clkCnt<7) {
1025 if (!clockFnd) *clock = clk[clkCnt];
1026 return ii;
1027 }
1028 //if we found errors see if it is lowest so far and save it as best run
1029 if (errCnt < bestErr[clkCnt]) {
1030 bestErr[clkCnt] = errCnt;
1031 bestStart[clkCnt] = ii;
1032 }
1033 }
1034 }
1035 uint8_t k;
1036 uint8_t best = 0;
1037 for (k=1; k < clkEnd; ++k){
1038 if (bestErr[k] < bestErr[best]){
1039 if (bestErr[k] == 0) bestErr[k]=1;
1040 // current best bit to error ratio vs new bit to error ratio
1041 if ( (size/clk[best])/bestErr[best] < (size/clk[k])/bestErr[k] ){
1042 best = k;
1043 }
1044 }
1045 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d", clk[k], bestErr[k], clk[best], bestStart[best]);
1046 }
1047 if (!clockFnd) *clock = clk[best];
1048 return bestStart[best];
1049 }
1050
1051 //by marshmellow
1052 //detect psk clock by reading each phase shift
1053 // a phase shift is determined by measuring the sample length of each wave
1054 int DetectPSKClock(uint8_t dest[], size_t size, int clock)
1055 {
1056 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
1057 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1058 if (size == 0) return 0;
1059 if (size<loopCnt) loopCnt = size-20;
1060
1061 //if we already have a valid clock quit
1062 size_t i=1;
1063 for (; i < 8; ++i)
1064 if (clk[i] == clock) return clock;
1065
1066 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
1067 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
1068 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
1069 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
1070 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
1071 fc = countFC(dest, size, 0);
1072 if (fc!=2 && fc!=4 && fc!=8) return -1;
1073 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
1074
1075 //find first full wave
1076 for (i=160; i<loopCnt; i++){
1077 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1078 if (waveStart == 0) {
1079 waveStart = i+1;
1080 //prnt("DEBUG: waveStart: %d",waveStart);
1081 } else {
1082 waveEnd = i+1;
1083 //prnt("DEBUG: waveEnd: %d",waveEnd);
1084 waveLenCnt = waveEnd-waveStart;
1085 if (waveLenCnt > fc){
1086 firstFullWave = waveStart;
1087 fullWaveLen=waveLenCnt;
1088 break;
1089 }
1090 waveStart=0;
1091 }
1092 }
1093 }
1094 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1095
1096 //test each valid clock from greatest to smallest to see which lines up
1097 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1098 lastClkBit = firstFullWave; //set end of wave as clock align
1099 waveStart = 0;
1100 errCnt=0;
1101 peakcnt=0;
1102 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
1103
1104 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1105 //top edge of wave = start of new wave
1106 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1107 if (waveStart == 0) {
1108 waveStart = i+1;
1109 waveLenCnt=0;
1110 } else { //waveEnd
1111 waveEnd = i+1;
1112 waveLenCnt = waveEnd-waveStart;
1113 if (waveLenCnt > fc){
1114 //if this wave is a phase shift
1115 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);
1116 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1117 peakcnt++;
1118 lastClkBit+=clk[clkCnt];
1119 } else if (i<lastClkBit+8){
1120 //noise after a phase shift - ignore
1121 } else { //phase shift before supposed to based on clock
1122 errCnt++;
1123 }
1124 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1125 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1126 }
1127 waveStart=i+1;
1128 }
1129 }
1130 }
1131 if (errCnt == 0){
1132 return clk[clkCnt];
1133 }
1134 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1135 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1136 }
1137 //all tested with errors
1138 //return the highest clk with the most peaks found
1139 uint8_t best=7;
1140 for (i=7; i>=1; i--){
1141 if (peaksdet[i] > peaksdet[best]) {
1142 best = i;
1143 }
1144 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
1145 }
1146 return clk[best];
1147 }
1148
1149 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1150 //find shortest transition from high to low
1151 size_t i = 0;
1152 size_t transition1 = 0;
1153 int lowestTransition = 255;
1154 bool lastWasHigh = false;
1155
1156 //find first valid beginning of a high or low wave
1157 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1158 ++i;
1159 while ((dest[i] < peak && dest[i] > low) && (i < size))
1160 ++i;
1161 lastWasHigh = (dest[i] >= peak);
1162
1163 if (i==size) return 0;
1164 transition1 = i;
1165
1166 for (;i < size; i++) {
1167 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1168 lastWasHigh = (dest[i] >= peak);
1169 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1170 transition1 = i;
1171 }
1172 }
1173 if (lowestTransition == 255) lowestTransition = 0;
1174 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
1175 return lowestTransition;
1176 }
1177
1178 //by marshmellow
1179 //detect nrz clock by reading #peaks vs no peaks(or errors)
1180 int DetectNRZClock(uint8_t dest[], size_t size, int clock)
1181 {
1182 size_t i=0;
1183 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1184 size_t loopCnt = 4096; //don't need to loop through entire array...
1185 if (size == 0) return 0;
1186 if (size<loopCnt) loopCnt = size-20;
1187 //if we already have a valid clock quit
1188 for (; i < 8; ++i)
1189 if (clk[i] == clock) return clock;
1190
1191 //get high and low peak
1192 int peak, low;
1193 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
1194
1195 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
1196 size_t ii;
1197 uint8_t clkCnt;
1198 uint8_t tol = 0;
1199 uint16_t smplCnt = 0;
1200 int16_t peakcnt = 0;
1201 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1202 uint16_t maxPeak = 255;
1203 bool firstpeak = false;
1204 //test for large clipped waves
1205 for (i=0; i<loopCnt; i++){
1206 if (dest[i] >= peak || dest[i] <= low){
1207 if (!firstpeak) continue;
1208 smplCnt++;
1209 } else {
1210 firstpeak=true;
1211 if (smplCnt > 6 ){
1212 if (maxPeak > smplCnt){
1213 maxPeak = smplCnt;
1214 //prnt("maxPk: %d",maxPeak);
1215 }
1216 peakcnt++;
1217 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1218 smplCnt=0;
1219 }
1220 }
1221 }
1222 bool errBitHigh = 0;
1223 bool bitHigh = 0;
1224 uint8_t ignoreCnt = 0;
1225 uint8_t ignoreWindow = 4;
1226 bool lastPeakHigh = 0;
1227 int lastBit = 0;
1228 peakcnt=0;
1229 //test each valid clock from smallest to greatest to see which lines up
1230 for(clkCnt=0; clkCnt < 8; ++clkCnt){
1231 //ignore clocks smaller than smallest peak
1232 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
1233 //try lining up the peaks by moving starting point (try first 256)
1234 for (ii=20; ii < loopCnt; ++ii){
1235 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1236 peakcnt=0;
1237 bitHigh = false;
1238 ignoreCnt = 0;
1239 lastBit = ii-clk[clkCnt];
1240 //loop through to see if this start location works
1241 for (i = ii; i < size-20; ++i) {
1242 //if we are at a clock bit
1243 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1244 //test high/low
1245 if (dest[i] >= peak || dest[i] <= low) {
1246 //if same peak don't count it
1247 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1248 peakcnt++;
1249 }
1250 lastPeakHigh = (dest[i] >= peak);
1251 bitHigh = true;
1252 errBitHigh = false;
1253 ignoreCnt = ignoreWindow;
1254 lastBit += clk[clkCnt];
1255 } else if (i == lastBit + clk[clkCnt] + tol) {
1256 lastBit += clk[clkCnt];
1257 }
1258 //else if not a clock bit and no peaks
1259 } else if (dest[i] < peak && dest[i] > low){
1260 if (ignoreCnt==0){
1261 bitHigh=false;
1262 if (errBitHigh==true) peakcnt--;
1263 errBitHigh=false;
1264 } else {
1265 ignoreCnt--;
1266 }
1267 // else if not a clock bit but we have a peak
1268 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1269 //error bar found no clock...
1270 errBitHigh=true;
1271 }
1272 }
1273 if(peakcnt>peaksdet[clkCnt]) {
1274 peaksdet[clkCnt]=peakcnt;
1275 }
1276 }
1277 }
1278 }
1279 int iii=7;
1280 uint8_t best=0;
1281 for (iii=7; iii > 0; iii--){
1282 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1283 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
1284 best = iii;
1285 }
1286 } else if (peaksdet[iii] > peaksdet[best]){
1287 best = iii;
1288 }
1289 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);
1290 }
1291
1292 return clk[best];
1293 }
1294
1295 // by marshmellow
1296 // convert psk1 demod to psk2 demod
1297 // only transition waves are 1s
1298 void psk1TOpsk2(uint8_t *bits, size_t size) {
1299 uint8_t lastBit = bits[0];
1300 for (size_t i = 1; i < size; i++){
1301 //ignore errors
1302 if (bits[i] == 7) continue;
1303
1304 if (lastBit != bits[i]){
1305 lastBit = bits[i];
1306 bits[i] = 1;
1307 } else {
1308 bits[i] = 0;
1309 }
1310 }
1311 }
1312
1313 // by marshmellow
1314 // convert psk2 demod to psk1 demod
1315 // from only transition waves are 1s to phase shifts change bit
1316 void psk2TOpsk1(uint8_t *bits, size_t size) {
1317 uint8_t phase = 0;
1318 for (size_t i = 0; i < size; i++){
1319 if (bits[i] == 1){
1320 phase ^= 1;
1321 }
1322 bits[i] = phase;
1323 }
1324 }
1325
1326 // redesigned by marshmellow adjusted from existing decode functions
1327 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1328 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1329 {
1330 //26 bit 40134 format (don't know other formats)
1331 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};
1332 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};
1333 size_t startidx = 0;
1334 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1335 // if didn't find preamble try again inverting
1336 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1337 *invert ^= 1;
1338 }
1339 if (*size != 64 && *size != 224) return -2;
1340 if (*invert==1)
1341 for (size_t i = startidx; i < *size; i++)
1342 bitStream[i] ^= 1;
1343
1344 return (int) startidx;
1345 }
1346
1347 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1348 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1349 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
1350 if (justNoise(dest, *size)) return -1;
1351 *clk = DetectNRZClock(dest, *size, *clk);
1352 if (*clk==0) return -2;
1353 size_t i, gLen = 4096;
1354 if (gLen>*size) gLen = *size-20;
1355 int high, low;
1356 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1357
1358 uint8_t bit=0;
1359 //convert wave samples to 1's and 0's
1360 for(i=20; i < *size-20; i++){
1361 if (dest[i] >= high) bit = 1;
1362 if (dest[i] <= low) bit = 0;
1363 dest[i] = bit;
1364 }
1365 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1366 size_t lastBit = 0;
1367 size_t numBits = 0;
1368 for(i=21; i < *size-20; i++) {
1369 //if transition detected or large number of same bits - store the passed bits
1370 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1371 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1372 numBits += (i - lastBit + (*clk/4)) / *clk;
1373 lastBit = i-1;
1374 }
1375 }
1376 *size = numBits;
1377 return 0;
1378 }
1379
1380 //by marshmellow
1381 //detects the bit clock for FSK given the high and low Field Clocks
1382 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1383 {
1384 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1385 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1386 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1387 uint8_t rfLensFnd = 0;
1388 uint8_t lastFCcnt = 0;
1389 uint16_t fcCounter = 0;
1390 uint16_t rfCounter = 0;
1391 uint8_t firstBitFnd = 0;
1392 size_t i;
1393 if (size == 0) return 0;
1394
1395 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1396 rfLensFnd=0;
1397 fcCounter=0;
1398 rfCounter=0;
1399 firstBitFnd=0;
1400 //prnt("DEBUG: fcTol: %d",fcTol);
1401 // prime i to first peak / up transition
1402 for (i = 160; i < size-20; i++)
1403 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1404 break;
1405
1406 for (; i < size-20; i++){
1407 fcCounter++;
1408 rfCounter++;
1409
1410 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1411 continue;
1412 // else new peak
1413 // if we got less than the small fc + tolerance then set it to the small fc
1414 // if it is inbetween set it to the last counter
1415 if (fcCounter < fcHigh && fcCounter > fcLow)
1416 fcCounter = lastFCcnt;
1417 else if (fcCounter < fcLow+fcTol)
1418 fcCounter = fcLow;
1419 else //set it to the large fc
1420 fcCounter = fcHigh;
1421
1422 //look for bit clock (rf/xx)
1423 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1424 //not the same size as the last wave - start of new bit sequence
1425 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1426 for (int ii=0; ii<15; ii++){
1427 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
1428 rfCnts[ii]++;
1429 rfCounter = 0;
1430 break;
1431 }
1432 }
1433 if (rfCounter > 0 && rfLensFnd < 15){
1434 //prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1435 rfCnts[rfLensFnd]++;
1436 rfLens[rfLensFnd++] = rfCounter;
1437 }
1438 } else {
1439 firstBitFnd++;
1440 }
1441 rfCounter=0;
1442 lastFCcnt=fcCounter;
1443 }
1444 fcCounter=0;
1445 }
1446 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1447
1448 for (i=0; i<15; i++){
1449 //get highest 2 RF values (might need to get more values to compare or compare all?)
1450 if (rfCnts[i]>rfCnts[rfHighest]){
1451 rfHighest3=rfHighest2;
1452 rfHighest2=rfHighest;
1453 rfHighest=i;
1454 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1455 rfHighest3=rfHighest2;
1456 rfHighest2=i;
1457 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1458 rfHighest3=i;
1459 }
1460 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
1461 }
1462 // set allowed clock remainder tolerance to be 1 large field clock length+1
1463 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1464 uint8_t tol1 = fcHigh+1;
1465
1466 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
1467
1468 // loop to find the highest clock that has a remainder less than the tolerance
1469 // compare samples counted divided by
1470 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1471 int ii=7;
1472 for (; ii>=2; ii--){
1473 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1474 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1475 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
1476 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
1477 break;
1478 }
1479 }
1480 }
1481 }
1482
1483 if (ii<2) return 0; // oops we went too far
1484
1485 return clk[ii];
1486 }
1487
1488 //by marshmellow
1489 //countFC is to detect the field clock lengths.
1490 //counts and returns the 2 most common wave lengths
1491 //mainly used for FSK field clock detection
1492 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
1493 {
1494 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1495 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1496 uint8_t fcLensFnd = 0;
1497 uint8_t lastFCcnt = 0;
1498 uint8_t fcCounter = 0;
1499 size_t i;
1500 if (size < 180) return 0;
1501
1502 // prime i to first up transition
1503 for (i = 160; i < size-20; i++)
1504 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1505 break;
1506
1507 for (; i < size-20; i++){
1508 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1509 // new up transition
1510 fcCounter++;
1511 if (fskAdj){
1512 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1513 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1514 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1515 if ((fcCounter==9) || fcCounter==4) fcCounter++;
1516 // save last field clock count (fc/xx)
1517 lastFCcnt = fcCounter;
1518 }
1519 // find which fcLens to save it to:
1520 for (int ii=0; ii<15; ii++){
1521 if (fcLens[ii]==fcCounter){
1522 fcCnts[ii]++;
1523 fcCounter=0;
1524 break;
1525 }
1526 }
1527 if (fcCounter>0 && fcLensFnd<15){
1528 //add new fc length
1529 fcCnts[fcLensFnd]++;
1530 fcLens[fcLensFnd++]=fcCounter;
1531 }
1532 fcCounter=0;
1533 } else {
1534 // count sample
1535 fcCounter++;
1536 }
1537 }
1538
1539 uint8_t best1=14, best2=14, best3=14;
1540 uint16_t maxCnt1=0;
1541 // go through fclens and find which ones are bigest 2
1542 for (i=0; i<15; i++){
1543 // get the 3 best FC values
1544 if (fcCnts[i]>maxCnt1) {
1545 best3=best2;
1546 best2=best1;
1547 maxCnt1=fcCnts[i];
1548 best1=i;
1549 } else if(fcCnts[i]>fcCnts[best2]){
1550 best3=best2;
1551 best2=i;
1552 } else if(fcCnts[i]>fcCnts[best3]){
1553 best3=i;
1554 }
1555 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]);
1556 }
1557 if (fcLens[best1]==0) return 0;
1558 uint8_t fcH=0, fcL=0;
1559 if (fcLens[best1]>fcLens[best2]){
1560 fcH=fcLens[best1];
1561 fcL=fcLens[best2];
1562 } else{
1563 fcH=fcLens[best2];
1564 fcL=fcLens[best1];
1565 }
1566 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1567 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]);
1568 return 0; //lots of waves not psk or fsk
1569 }
1570 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1571
1572 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
1573 if (fskAdj) return fcs;
1574 return fcLens[best1];
1575 }
1576
1577 //by marshmellow - demodulate PSK1 wave
1578 //uses wave lengths (# Samples)
1579 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1580 {
1581 if (size == 0) return -1;
1582 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1583 if (*size<loopCnt) loopCnt = *size;
1584
1585 size_t numBits=0;
1586 uint8_t curPhase = *invert;
1587 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1588 uint16_t fc=0, fullWaveLen=0, tol=1;
1589 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1590 fc = countFC(dest, *size, 1);
1591 uint8_t fc2 = fc >> 8;
1592 if (fc2 == 10) return -1; //fsk found - quit
1593 fc = fc & 0xFF;
1594 if (fc!=2 && fc!=4 && fc!=8) return -1;
1595 //prnt("DEBUG: FC: %d",fc);
1596 *clock = DetectPSKClock(dest, *size, *clock);
1597 if (*clock == 0) return -1;
1598
1599 //find start of modulating data in trace
1600 uint8_t threshold_value = 123; //-5
1601 i = findModStart(dest, *size, threshold_value, fc);
1602
1603 //find first phase shift
1604 int avgWaveVal=0, lastAvgWaveVal=0;
1605 waveStart = i;
1606 for (; i<loopCnt; i++){
1607 // find peak
1608 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1609 waveEnd = i+1;
1610 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
1611 waveLenCnt = waveEnd-waveStart;
1612 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
1613 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1614 firstFullWave = waveStart;
1615 fullWaveLen=waveLenCnt;
1616 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1617 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
1618 break;
1619 }
1620 waveStart = i+1;
1621 avgWaveVal = 0;
1622 }
1623 avgWaveVal += dest[i+2];
1624 }
1625 if (firstFullWave == 0) {
1626 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1627 // so skip a little to ensure we are past any Start Signal
1628 firstFullWave = 160;
1629 memset(dest, curPhase, firstFullWave / *clock);
1630 } else {
1631 memset(dest, curPhase^1, firstFullWave / *clock);
1632 }
1633 //advance bits
1634 numBits += (firstFullWave / *clock);
1635 //set start of wave as clock align
1636 lastClkBit = firstFullWave;
1637 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
1638 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1639 waveStart = 0;
1640 dest[numBits++] = curPhase; //set first read bit
1641 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1642 //top edge of wave = start of new wave
1643 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1644 if (waveStart == 0) {
1645 waveStart = i+1;
1646 waveLenCnt = 0;
1647 avgWaveVal = dest[i+1];
1648 } else { //waveEnd
1649 waveEnd = i+1;
1650 waveLenCnt = waveEnd-waveStart;
1651 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1652 if (waveLenCnt > fc){
1653 //prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1654 //this wave is a phase shift
1655 //prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1656 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1657 curPhase ^= 1;
1658 dest[numBits++] = curPhase;
1659 lastClkBit += *clock;
1660 } else if (i < lastClkBit+10+fc){
1661 //noise after a phase shift - ignore
1662 } else { //phase shift before supposed to based on clock
1663 errCnt++;
1664 dest[numBits++] = 7;
1665 }
1666 } else if (i+1 > lastClkBit + *clock + tol + fc){
1667 lastClkBit += *clock; //no phase shift but clock bit
1668 dest[numBits++] = curPhase;
1669 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1670 errCnt2++;
1671 if(errCnt2 > 101) return errCnt2;
1672 }
1673 avgWaveVal = 0;
1674 waveStart = i+1;
1675 }
1676 }
1677 avgWaveVal += dest[i+1];
1678 }
1679 *size = numBits;
1680 return errCnt;
1681 }
1682
1683 //by marshmellow
1684 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1685 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1686 size_t bufsize = *size;
1687 //need to loop through all samples and identify our clock, look for the ST pattern
1688 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1689 int clk = 0;
1690 int tol = 0;
1691 int i, j, skip, start, end, low, high, minClk, waveStart;
1692 bool complete = false;
1693 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1694 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
1695 size_t testsize = (bufsize < 512) ? bufsize : 512;
1696 int phaseoff = 0;
1697 high = low = 128;
1698 memset(tmpbuff, 0, sizeof(tmpbuff));
1699 memset(waveLen, 0, sizeof(waveLen));
1700
1701
1702 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1703 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1704 return false; //just noise
1705 }
1706 i = 0;
1707 j = 0;
1708 minClk = 255;
1709 // get to first full low to prime loop and skip incomplete first pulse
1710 while ((buffer[i] < high) && (i < bufsize))
1711 ++i;
1712 while ((buffer[i] > low) && (i < bufsize))
1713 ++i;
1714 skip = i;
1715
1716 // populate tmpbuff buffer with pulse lengths
1717 while (i < bufsize) {
1718 // measure from low to low
1719 while ((buffer[i] > low) && (i < bufsize))
1720 ++i;
1721 start= i;
1722 while ((buffer[i] < high) && (i < bufsize))
1723 ++i;
1724 //first high point for this wave
1725 waveStart = i;
1726 while ((buffer[i] > low) && (i < bufsize))
1727 ++i;
1728 if (j >= (bufsize/32)) {
1729 break;
1730 }
1731 waveLen[j] = i - waveStart; //first high to first low
1732 tmpbuff[j++] = i - start;
1733 if (i-start < minClk && i < bufsize) {
1734 minClk = i - start;
1735 }
1736 }
1737 // set clock - might be able to get this externally and remove this work...
1738 if (!clk) {
1739 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1740 tol = fndClk[clkCnt]/8;
1741 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1742 clk=fndClk[clkCnt];
1743 break;
1744 }
1745 }
1746 // clock not found - ERROR
1747 if (!clk) {
1748 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1749 return false;
1750 }
1751 } else tol = clk/8;
1752
1753 *foundclock = clk;
1754
1755 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1756 start = -1;
1757 for (i = 0; i < j - 4; ++i) {
1758 skip += 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 start = i + 3;
1764 break;
1765 }
1766 }
1767 }
1768 }
1769 }
1770 // first ST not found - ERROR
1771 if (start < 0) {
1772 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1773 return false;
1774 } else {
1775 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
1776 }
1777 if (waveLen[i+2] > clk*1+tol)
1778 phaseoff = 0;
1779 else
1780 phaseoff = clk/2;
1781
1782 // skip over the remainder of ST
1783 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1784
1785 // now do it again to find the end
1786 end = skip;
1787 for (i += 3; i < j - 4; ++i) {
1788 end += tmpbuff[i];
1789 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1790 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
1791 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
1792 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1793 complete = true;
1794 break;
1795 }
1796 }
1797 }
1798 }
1799 }
1800 end -= phaseoff;
1801 //didn't find second ST - ERROR
1802 if (!complete) {
1803 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1804 return false;
1805 }
1806 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);
1807 //now begin to trim out ST so we can use normal demod cmds
1808 start = skip;
1809 size_t datalen = end - start;
1810 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1811 if ( clk - (datalen % clk) <= clk/8) {
1812 // padd the amount off - could be problematic... but shouldn't happen often
1813 datalen += clk - (datalen % clk);
1814 } else if ( (datalen % clk) <= clk/8 ) {
1815 // padd the amount off - could be problematic... but shouldn't happen often
1816 datalen -= datalen % clk;
1817 } else {
1818 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1819 return false;
1820 }
1821 // if datalen is less than one t55xx block - ERROR
1822 if (datalen/clk < 8*4) {
1823 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1824 return false;
1825 }
1826 size_t dataloc = start;
1827 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1828 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1829 for ( i=0; i <= (clk/8); ++i ) {
1830 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1831 dataloc -= i;
1832 break;
1833 }
1834 }
1835 }
1836
1837 size_t newloc = 0;
1838 i=0;
1839 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1840
1841 // warning - overwriting buffer given with raw wave data with ST removed...
1842 while ( dataloc < bufsize-(clk/2) ) {
1843 //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)
1844 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1845 for(i=0; i < clk/2-tol; ++i) {
1846 buffer[dataloc+i] = high+5;
1847 }
1848 } //test for single sample outlier (high between two lows) in the case of very strong waves
1849 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1850 buffer[dataloc] = buffer[dataloc+2];
1851 buffer[dataloc+1] = buffer[dataloc+2];
1852 }
1853 for (i=0; i<datalen; ++i) {
1854 if (i+newloc < bufsize) {
1855 if (i+newloc < dataloc)
1856 buffer[i+newloc] = buffer[dataloc];
1857
1858 dataloc++;
1859 }
1860 }
1861 newloc += i;
1862 //skip next ST - we just assume it will be there from now on...
1863 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1864 dataloc += clk*4;
1865 }
1866 *size = newloc;
1867 return true;
1868 }
Impressum, Datenschutz