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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 <string.h>
13 #include "lfdemod.h"
14
15
16 uint8_t justNoise(uint8_t *BitStream, size_t size)
17 {
18 static const uint8_t THRESHOLD = 123;
19 //test samples are not just noise
20 uint8_t justNoise1 = 1;
21 for(size_t idx=0; idx < size && justNoise1 ;idx++){
22 justNoise1 = BitStream[idx] < THRESHOLD;
23 }
24 return justNoise1;
25 }
26
27 //by marshmellow
28 //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
29 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
30 {
31 *high=0;
32 *low=255;
33 // get high and low thresholds
34 for (int i=0; i < size; i++){
35 if (BitStream[i] > *high) *high = BitStream[i];
36 if (BitStream[i] < *low) *low = BitStream[i];
37 }
38 if (*high < 123) return -1; // just noise
39 *high = (int)(((*high-128)*(((float)fuzzHi)/100))+128);
40 *low = (int)(((*low-128)*(((float)fuzzLo)/100))+128);
41 return 1;
42 }
43
44 // by marshmellow
45 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
46 // returns 1 if passed
47 uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
48 {
49 uint8_t ans = 0;
50 for (uint8_t i = 0; i < bitLen; i++){
51 ans ^= ((bits >> i) & 1);
52 }
53 //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
54 return (ans == pType);
55 }
56
57 //by marshmellow
58 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
59 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
60 {
61 uint8_t foundCnt=0;
62 for (int idx=0; idx < *size - pLen; idx++){
63 if (memcmp(BitStream+idx, preamble, pLen) == 0){
64 //first index found
65 foundCnt++;
66 if (foundCnt == 1){
67 *startIdx = idx;
68 }
69 if (foundCnt == 2){
70 *size = idx - *startIdx;
71 return 1;
72 }
73 }
74 }
75 return 0;
76 }
77
78
79 //by marshmellow
80 //takes 1s and 0s and searches for EM410x format - output EM ID
81 uint64_t Em410xDecodeOld(uint8_t *BitStream, size_t *size, size_t *startIdx)
82 {
83 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
84 // otherwise could be a void with no arguments
85 //set defaults
86 uint64_t lo=0;
87 uint32_t i = 0;
88 if (BitStream[1]>1){ //allow only 1s and 0s
89 // PrintAndLog("no data found");
90 return 0;
91 }
92 // 111111111 bit pattern represent start of frame
93 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1};
94 uint32_t idx = 0;
95 uint32_t parityBits = 0;
96 uint8_t errChk = 0;
97 *startIdx = 0;
98 for (uint8_t extraBitChk=0; extraBitChk<5; extraBitChk++){
99 errChk = preambleSearch(BitStream+extraBitChk+*startIdx, preamble, sizeof(preamble), size, startIdx);
100 if (errChk == 0) return 0;
101 idx = *startIdx + 9;
102 for (i=0; i<10;i++){ //loop through 10 sets of 5 bits (50-10p = 40 bits)
103 parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
104 //check even parity
105 if (parityTest(parityBits, 5, 0) == 0){
106 //parity failed try next bit (in the case of 1111111111) but last 9 = preamble
107 startIdx++;
108 errChk = 0;
109 break;
110 }
111 //set uint64 with ID from BitStream
112 for (uint8_t ii=0; ii<4; ii++){
113 lo = (lo << 1LL) | (BitStream[(i*5)+ii+idx]);
114 }
115 }
116 if (errChk != 0) return lo;
117 //skip last 5 bit parity test for simplicity.
118 // *size = 64;
119 }
120 return 0;
121 }
122
123 //by marshmellow
124 //takes 1s and 0s and searches for EM410x format - output EM ID
125 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
126 {
127 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
128 // otherwise could be a void with no arguments
129 //set defaults
130 uint32_t i = 0;
131 if (BitStream[1]>1){ //allow only 1s and 0s
132 // PrintAndLog("no data found");
133 return 0;
134 }
135 // 111111111 bit pattern represent start of frame
136 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1};
137 uint32_t idx = 0;
138 uint32_t parityBits = 0;
139 uint8_t errChk = 0;
140 uint8_t FmtLen = 10;
141 *startIdx = 0;
142 for (uint8_t extraBitChk=0; extraBitChk<5; extraBitChk++){
143 errChk = preambleSearch(BitStream+extraBitChk+*startIdx, preamble, sizeof(preamble), size, startIdx);
144 if (errChk == 0) return 0;
145 if (*size<64) return 0;
146 if (*size>64) FmtLen = 22;
147 idx = *startIdx + 9;
148 for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
149 parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
150 //check even parity
151 if (parityTest(parityBits, 5, 0) == 0){
152 //parity failed try next bit (in the case of 1111111111) but last 9 = preamble
153 startIdx++;
154 errChk = 0;
155 break;
156 }
157 //set uint64 with ID from BitStream
158 for (uint8_t ii=0; ii<4; ii++){
159 *hi = (*hi << 1) | (*lo >> 63);
160 *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
161 }
162 }
163 if (errChk != 0) return 1;
164 //skip last 5 bit parity test for simplicity.
165 // *size = 64 | 128;
166 }
167 return 0;
168 }
169
170 //by marshmellow
171 //takes 3 arguments - clock, invert, maxErr as integers
172 //attempts to demodulate ask while decoding manchester
173 //prints binary found and saves in graphbuffer for further commands
174 int askmandemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr)
175 {
176 int i;
177 //int clk2=*clk;
178 int start = DetectASKClock(BinStream, *size, clk, 20); //clock default
179 if (*clk==0) return -3;
180 if (start < 0) return -3;
181 // if autodetected too low then adjust //MAY NEED ADJUSTMENT
182 //if (clk2==0 && *clk<8) *clk =64;
183 //if (clk2==0 && *clk<32) *clk=32;
184 if (*invert != 0 && *invert != 1) *invert=0;
185 uint32_t initLoopMax = 200;
186 if (initLoopMax > *size) initLoopMax=*size;
187 // Detect high and lows
188 // 25% fuzz in case highs and lows aren't clipped [marshmellow]
189 int high, low, ans;
190 ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
191 if (ans<1) return -2; //just noise
192
193 // PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
194 int lastBit = 0; //set first clock check
195 uint32_t bitnum = 0; //output counter
196 int tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
197 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
198 int iii = 0;
199 uint32_t gLen = *size;
200 if (gLen > 3000) gLen=3000;
201 //if 0 errors allowed then only try first 2 clock cycles as we want a low tolerance
202 if (!maxErr) gLen=*clk*2;
203 uint8_t errCnt =0;
204 uint16_t MaxBits = 500;
205 uint32_t bestStart = *size;
206 int bestErrCnt = maxErr+1;
207 // PrintAndLog("DEBUG - lastbit - %d",lastBit);
208 // loop to find first wave that works
209 for (iii=0; iii < gLen; ++iii){
210 if ((BinStream[iii] >= high) || (BinStream[iii] <= low)){
211 lastBit=iii-*clk;
212 errCnt=0;
213 // loop through to see if this start location works
214 for (i = iii; i < *size; ++i) {
215 if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
216 lastBit+=*clk;
217 } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
218 //low found and we are expecting a bar
219 lastBit+=*clk;
220 } else {
221 //mid value found or no bar supposed to be here
222 if ((i-lastBit)>(*clk+tol)){
223 //should have hit a high or low based on clock!!
224
225 //debug
226 //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
227
228 errCnt++;
229 lastBit+=*clk;//skip over until hit too many errors
230 if (errCnt>(maxErr)) break; //allow 1 error for every 1000 samples else start over
231 }
232 }
233 if ((i-iii) >(MaxBits * *clk)) break; //got plenty of bits
234 }
235 //we got more than 64 good bits and not all errors
236 if ((((i-iii)/ *clk) > (64)) && (errCnt<=maxErr)) {
237 //possible good read
238 if (errCnt==0){
239 bestStart=iii;
240 bestErrCnt=errCnt;
241 break; //great read - finish
242 }
243 if (errCnt<bestErrCnt){ //set this as new best run
244 bestErrCnt=errCnt;
245 bestStart = iii;
246 }
247 }
248 }
249 }
250 if (bestErrCnt<=maxErr){
251 //best run is good enough set to best run and set overwrite BinStream
252 iii=bestStart;
253 lastBit = bestStart - *clk;
254 bitnum=0;
255 for (i = iii; i < *size; ++i) {
256 if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
257 lastBit += *clk;
258 BinStream[bitnum] = *invert;
259 bitnum++;
260 } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
261 //low found and we are expecting a bar
262 lastBit+=*clk;
263 BinStream[bitnum] = 1-*invert;
264 bitnum++;
265 } else {
266 //mid value found or no bar supposed to be here
267 if ((i-lastBit)>(*clk+tol)){
268 //should have hit a high or low based on clock!!
269
270 //debug
271 //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
272 if (bitnum > 0){
273 BinStream[bitnum]=77;
274 bitnum++;
275 }
276
277 lastBit+=*clk;//skip over error
278 }
279 }
280 if (bitnum >=MaxBits) break;
281 }
282 *size=bitnum;
283 } else{
284 *invert=bestStart;
285 *clk=iii;
286 return -1;
287 }
288 return bestErrCnt;
289 }
290
291 //by marshmellow
292 //encode binary data into binary manchester
293 int ManchesterEncode(uint8_t *BitStream, size_t size)
294 {
295 size_t modIdx=20000, i=0;
296 if (size>modIdx) return -1;
297 for (size_t idx=0; idx < size; idx++){
298 BitStream[idx+modIdx++] = BitStream[idx];
299 BitStream[idx+modIdx++] = BitStream[idx]^1;
300 }
301 for (; i<(size*2); i++){
302 BitStream[i] = BitStream[i+20000];
303 }
304 return i;
305 }
306
307 //by marshmellow
308 //take 10 and 01 and manchester decode
309 //run through 2 times and take least errCnt
310 int manrawdecode(uint8_t * BitStream, size_t *size)
311 {
312 uint16_t bitnum=0;
313 uint16_t MaxBits = 500;
314 uint16_t errCnt = 0;
315 size_t i=1;
316 uint16_t bestErr = 1000;
317 uint16_t bestRun = 0;
318 size_t ii=1;
319 if (size == 0) return -1;
320 for (ii=1;ii<3;++ii){
321 i=1;
322 for (i=i+ii;i<*size-2;i+=2){
323 if(BitStream[i]==1 && (BitStream[i+1]==0)){
324 } else if((BitStream[i]==0)&& BitStream[i+1]==1){
325 } else {
326 errCnt++;
327 }
328 if(bitnum>MaxBits) break;
329 }
330 if (bestErr>errCnt){
331 bestErr=errCnt;
332 bestRun=ii;
333 }
334 errCnt=0;
335 }
336 errCnt=bestErr;
337 if (errCnt<20){
338 ii=bestRun;
339 i=1;
340 for (i=i+ii; i < *size-2; i+=2){
341 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
342 BitStream[bitnum++]=0;
343 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
344 BitStream[bitnum++]=1;
345 } else {
346 BitStream[bitnum++]=77;
347 //errCnt++;
348 }
349 if(bitnum>MaxBits) break;
350 }
351 *size=bitnum;
352 }
353 return errCnt;
354 }
355
356 //by marshmellow
357 //take 01 or 10 = 1 and 11 or 00 = 0
358 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
359 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
360 {
361 uint16_t bitnum=0;
362 uint32_t errCnt =0;
363 size_t i=offset;
364 uint16_t MaxBits=512;
365 //if not enough samples - error
366 if (*size < 51) return -1;
367 //check for phase change faults - skip one sample if faulty
368 uint8_t offsetA = 1, offsetB = 1;
369 for (; i<48; i+=2){
370 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
371 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
372 }
373 if (!offsetA && offsetB) offset++;
374 for (i=offset; i<*size-3; i+=2){
375 //check for phase error
376 if (i<*size-3 && BitStream[i+1]==BitStream[i+2]) {
377 BitStream[bitnum++]=77;
378 errCnt++;
379 }
380 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
381 BitStream[bitnum++]=1^invert;
382 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
383 BitStream[bitnum++]=invert;
384 } else {
385 BitStream[bitnum++]=77;
386 errCnt++;
387 }
388 if(bitnum>MaxBits) break;
389 }
390 *size=bitnum;
391 return errCnt;
392 }
393
394 //by marshmellow
395 void askAmp(uint8_t *BitStream, size_t size)
396 {
397 int shift = 127;
398 int shiftedVal=0;
399 for(int i = 1; i<size; i++){
400 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
401 shift=127;
402 else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
403 shift=-127;
404
405 shiftedVal=BitStream[i]+shift;
406
407 if (shiftedVal>255)
408 shiftedVal=255;
409 else if (shiftedVal<0)
410 shiftedVal=0;
411 BitStream[i-1] = shiftedVal;
412 }
413 return;
414 }
415
416 //by marshmellow
417 //takes 3 arguments - clock, invert and maxErr as integers
418 //attempts to demodulate ask only
419 int askrawdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp)
420 {
421 uint32_t i;
422 if (*size==0) return -1;
423 int start = DetectASKClock(BinStream, *size, clk, 20); //clock default
424 if (*clk==0) return -1;
425 if (start<0) return -1;
426 if (*invert != 0 && *invert != 1) *invert =0;
427 uint32_t initLoopMax = 200;
428 if (initLoopMax > *size) initLoopMax=*size;
429 // Detect high and lows
430 //25% fuzz in case highs and lows aren't clipped [marshmellow]
431 int high, low, ans;
432 if (amp==1) askAmp(BinStream, *size);
433 ans = getHiLo(BinStream, initLoopMax, &high, &low, 75, 75);
434 if (ans<1) return -1; //just noise
435
436 //PrintAndLog("DEBUG - valid high: %d - valid low: %d",high,low);
437 int lastBit = 0; //set first clock check
438 uint32_t bitnum = 0; //output counter
439 uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock
440 // if they fall + or - this value + clock from last valid wave
441 if (*clk == 32) tol=0; //clock tolerance may not be needed anymore currently set to
442 // + or - 1 but could be increased for poor waves or removed entirely
443 uint32_t iii = 0;
444 uint32_t gLen = *size;
445 if (gLen > 500) gLen=500;
446 //if 0 errors allowed then only try first 2 clock cycles as we want a low tolerance
447 if (!maxErr) gLen=*clk*2;
448 uint8_t errCnt =0;
449 uint32_t bestStart = *size;
450 uint32_t bestErrCnt = maxErr; //(*size/1000);
451 uint8_t midBit=0;
452 uint16_t MaxBits=1000;
453 //PrintAndLog("DEBUG - lastbit - %d",lastBit);
454 //loop to find first wave that works
455 for (iii=start; iii < gLen; ++iii){
456 if ((BinStream[iii]>=high) || (BinStream[iii]<=low)){
457 lastBit=iii-*clk;
458 errCnt=0;
459 //loop through to see if this start location works
460 for (i = iii; i < *size; ++i) {
461 if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
462 lastBit+=*clk;
463 midBit=0;
464 } else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
465 //low found and we are expecting a bar
466 lastBit+=*clk;
467 midBit=0;
468 } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
469 //mid bar?
470 midBit=1;
471 } else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
472 //mid bar?
473 midBit=1;
474 } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
475 //no mid bar found
476 midBit=1;
477 } else {
478 //mid value found or no bar supposed to be here
479
480 if ((i-lastBit)>(*clk+tol)){
481 //should have hit a high or low based on clock!!
482 //debug
483 //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
484
485 errCnt++;
486 lastBit+=*clk;//skip over until hit too many errors
487 if (errCnt > maxErr){
488 //errCnt=0;
489 break;
490 }
491 }
492 }
493 if ((i-iii)>(MaxBits * *clk)) break; //got enough bits
494 }
495 //we got more than 64 good bits and not all errors
496 if ((((i-iii)/ *clk) > (64)) && (errCnt<=maxErr)) {
497 //possible good read
498 if (errCnt==0){
499 bestStart=iii;
500 bestErrCnt=errCnt;
501 break; //great read - finish
502 }
503 if (errCnt<bestErrCnt){ //set this as new best run
504 bestErrCnt=errCnt;
505 bestStart = iii;
506 }
507 }
508 }
509 }
510 if (bestErrCnt<=maxErr){
511 //best run is good enough - set to best run and overwrite BinStream
512 iii = bestStart;
513 lastBit = bestStart - *clk;
514 bitnum=0;
515 for (i = iii; i < *size; ++i) {
516 if ((BinStream[i] >= high) && ((i-lastBit) > (*clk-tol))){
517 lastBit += *clk;
518 BinStream[bitnum] = *invert;
519 bitnum++;
520 midBit=0;
521 } else if ((BinStream[i] <= low) && ((i-lastBit) > (*clk-tol))){
522 //low found and we are expecting a bar
523 lastBit+=*clk;
524 BinStream[bitnum] = 1 - *invert;
525 bitnum++;
526 midBit=0;
527 } else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
528 //mid bar?
529 midBit=1;
530 BinStream[bitnum] = 1 - *invert;
531 bitnum++;
532 } else if ((BinStream[i]>=high) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
533 //mid bar?
534 midBit=1;
535 BinStream[bitnum] = *invert;
536 bitnum++;
537 } else if ((i-lastBit)>((*clk/2)+tol) && (midBit==0)){
538 //no mid bar found
539 midBit=1;
540 if (bitnum!=0) BinStream[bitnum] = BinStream[bitnum-1];
541 bitnum++;
542
543 } else {
544 //mid value found or no bar supposed to be here
545 if ((i-lastBit)>(*clk+tol)){
546 //should have hit a high or low based on clock!!
547
548 //debug
549 //PrintAndLog("DEBUG - no wave in expected area - location: %d, expected: %d-%d, lastBit: %d - resetting search",i,(lastBit+(clk-((int)(tol)))),(lastBit+(clk+((int)(tol)))),lastBit);
550 if (bitnum > 0){
551 BinStream[bitnum]=77;
552 bitnum++;
553 }
554 lastBit+=*clk;//skip over error
555 }
556 }
557 if (bitnum >= MaxBits) break;
558 }
559 *size=bitnum;
560 } else{
561 *invert=bestStart;
562 *clk=iii;
563 return -1;
564 }
565 return bestErrCnt;
566 }
567
568 // demod gProxIIDemod
569 // error returns as -x
570 // success returns start position in BitStream
571 // BitStream must contain previously askrawdemod and biphasedemoded data
572 int gProxII_Demod(uint8_t BitStream[], size_t *size)
573 {
574 size_t startIdx=0;
575 uint8_t preamble[] = {1,1,1,1,1,0};
576
577 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
578 if (errChk == 0) return -3; //preamble not found
579 if (*size != 96) return -2; //should have found 96 bits
580 //check first 6 spacer bits to verify format
581 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
582 //confirmed proper separator bits found
583 //return start position
584 return (int) startIdx;
585 }
586 return -5;
587 }
588
589 //translate wave to 11111100000 (1 for each short wave 0 for each long wave)
590 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
591 {
592 uint32_t last_transition = 0;
593 uint32_t idx = 1;
594 //uint32_t maxVal=0;
595 if (fchigh==0) fchigh=10;
596 if (fclow==0) fclow=8;
597 //set the threshold close to 0 (graph) or 128 std to avoid static
598 uint8_t threshold_value = 123;
599
600 // sync to first lo-hi transition, and threshold
601
602 // Need to threshold first sample
603
604 if(dest[0] < threshold_value) dest[0] = 0;
605 else dest[0] = 1;
606
607 size_t numBits = 0;
608 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
609 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
610 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
611 for(idx = 1; idx < size; idx++) {
612 // threshold current value
613
614 if (dest[idx] < threshold_value) dest[idx] = 0;
615 else dest[idx] = 1;
616
617 // Check for 0->1 transition
618 if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
619 if ((idx-last_transition)<(fclow-2)){ //0-5 = garbage noise
620 //do nothing with extra garbage
621 } else if ((idx-last_transition) < (fchigh-1)) { //6-8 = 8 waves
622 dest[numBits]=1;
623 } else { //9+ = 10 waves
624 dest[numBits]=0;
625 }
626 last_transition = idx;
627 numBits++;
628 }
629 }
630 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
631 }
632
633 uint32_t myround2(float f)
634 {
635 if (f >= 2000) return 2000;//something bad happened
636 return (uint32_t) (f + (float)0.5);
637 }
638
639 //translate 11111100000 to 10
640 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t maxConsequtiveBits,
641 uint8_t invert, uint8_t fchigh, uint8_t fclow)
642 {
643 uint8_t lastval=dest[0];
644 uint32_t idx=0;
645 size_t numBits=0;
646 uint32_t n=1;
647
648 for( idx=1; idx < size; idx++) {
649
650 if (dest[idx]==lastval) {
651 n++;
652 continue;
653 }
654 //if lastval was 1, we have a 1->0 crossing
655 if ( dest[idx-1]==1 ) {
656 n=myround2((float)(n+1)/((float)(rfLen)/(float)fclow));
657 } else {// 0->1 crossing
658 n=myround2((float)(n+1)/((float)(rfLen-1)/(float)fchigh)); //-1 for fudge factor
659 }
660 if (n == 0) n = 1;
661
662 if(n < maxConsequtiveBits) //Consecutive
663 {
664 if(invert==0){ //invert bits
665 memset(dest+numBits, dest[idx-1] , n);
666 }else{
667 memset(dest+numBits, dest[idx-1]^1 , n);
668 }
669 numBits += n;
670 }
671 n=0;
672 lastval=dest[idx];
673 }//end for
674 return numBits;
675 }
676 //by marshmellow (from holiman's base)
677 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
678 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
679 {
680 // FSK demodulator
681 size = fsk_wave_demod(dest, size, fchigh, fclow);
682 size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow);
683 return size;
684 }
685
686 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
687 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
688 {
689 if (justNoise(dest, *size)) return -1;
690
691 size_t numStart=0, size2=*size, startIdx=0;
692 // FSK demodulator
693 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
694 if (*size < 96) return -2;
695 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
696 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
697 // find bitstring in array
698 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
699 if (errChk == 0) return -3; //preamble not found
700
701 numStart = startIdx + sizeof(preamble);
702 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
703 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
704 if (dest[idx] == dest[idx+1]){
705 return -4; //not manchester data
706 }
707 *hi2 = (*hi2<<1)|(*hi>>31);
708 *hi = (*hi<<1)|(*lo>>31);
709 //Then, shift in a 0 or one into low
710 if (dest[idx] && !dest[idx+1]) // 1 0
711 *lo=(*lo<<1)|1;
712 else // 0 1
713 *lo=(*lo<<1)|0;
714 }
715 return (int)startIdx;
716 }
717
718 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
719 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
720 {
721 if (justNoise(dest, *size)) return -1;
722
723 size_t numStart=0, size2=*size, startIdx=0;
724 // FSK demodulator
725 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
726 if (*size < 96) return -2;
727
728 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
729 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
730
731 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
732 if (errChk == 0) return -3; //preamble not found
733
734 numStart = startIdx + sizeof(preamble);
735 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
736 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
737 if (dest[idx] == dest[idx+1])
738 return -4; //not manchester data
739 *hi2 = (*hi2<<1)|(*hi>>31);
740 *hi = (*hi<<1)|(*lo>>31);
741 //Then, shift in a 0 or one into low
742 if (dest[idx] && !dest[idx+1]) // 1 0
743 *lo=(*lo<<1)|1;
744 else // 0 1
745 *lo=(*lo<<1)|0;
746 }
747 return (int)startIdx;
748 }
749
750 uint32_t bytebits_to_byte(uint8_t* src, size_t numbits)
751 {
752 uint32_t num = 0;
753 for(int i = 0 ; i < numbits ; i++)
754 {
755 num = (num << 1) | (*src);
756 src++;
757 }
758 return num;
759 }
760
761 int IOdemodFSK(uint8_t *dest, size_t size)
762 {
763 if (justNoise(dest, size)) return -1;
764 //make sure buffer has data
765 if (size < 66*64) return -2;
766 // FSK demodulator
767 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
768 if (size < 65) return -3; //did we get a good demod?
769 //Index map
770 //0 10 20 30 40 50 60
771 //| | | | | | |
772 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
773 //-----------------------------------------------------------------------------
774 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
775 //
776 //XSF(version)facility:codeone+codetwo
777 //Handle the data
778 size_t startIdx = 0;
779 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
780 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
781 if (errChk == 0) return -4; //preamble not found
782
783 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
784 //confirmed proper separator bits found
785 //return start position
786 return (int) startIdx;
787 }
788 return -5;
789 }
790
791 // by marshmellow
792 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
793 // Parity Type (1 for odd 0 for even), and binary Length (length to run)
794 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
795 {
796 uint32_t parityWd = 0;
797 size_t j = 0, bitCnt = 0;
798 for (int word = 0; word < (bLen); word+=pLen){
799 for (int bit=0; bit < pLen; bit++){
800 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
801 BitStream[j++] = (BitStream[startIdx+word+bit]);
802 }
803 j--;
804 // if parity fails then return 0
805 if (parityTest(parityWd, pLen, pType) == 0) return -1;
806 bitCnt+=(pLen-1);
807 parityWd = 0;
808 }
809 // if we got here then all the parities passed
810 //return ID start index and size
811 return bitCnt;
812 }
813
814 // by marshmellow
815 // FSK Demod then try to locate an AWID ID
816 int AWIDdemodFSK(uint8_t *dest, size_t *size)
817 {
818 //make sure buffer has enough data
819 if (*size < 96*50) return -1;
820
821 if (justNoise(dest, *size)) return -2;
822
823 // FSK demodulator
824 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
825 if (*size < 96) return -3; //did we get a good demod?
826
827 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
828 size_t startIdx = 0;
829 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
830 if (errChk == 0) return -4; //preamble not found
831 if (*size != 96) return -5;
832 return (int)startIdx;
833 }
834
835 // by marshmellow
836 // FSK Demod then try to locate an Farpointe Data (pyramid) ID
837 int PyramiddemodFSK(uint8_t *dest, size_t *size)
838 {
839 //make sure buffer has data
840 if (*size < 128*50) return -5;
841
842 //test samples are not just noise
843 if (justNoise(dest, *size)) return -1;
844
845 // FSK demodulator
846 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
847 if (*size < 128) return -2; //did we get a good demod?
848
849 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
850 size_t startIdx = 0;
851 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
852 if (errChk == 0) return -4; //preamble not found
853 if (*size != 128) return -3;
854 return (int)startIdx;
855 }
856
857
858 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, int high, int low)
859 {
860 uint8_t allPeaks=1;
861 uint16_t cntPeaks=0;
862 for (size_t i=20; i<255; i++){
863 if (dest[i]>low && dest[i]<high)
864 allPeaks=0;
865 else
866 cntPeaks++;
867 }
868 if (allPeaks==0){
869 if (cntPeaks>190) return 1;
870 }
871 return allPeaks;
872 }
873
874 // by marshmellow
875 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
876 // maybe somehow adjust peak trimming value based on samples to fix?
877 // return start index of best starting position for that clock and return clock (by reference)
878 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
879 {
880 int i=0;
881 int clk[]={8,16,32,40,50,64,100,128,256};
882 int loopCnt = 256; //don't need to loop through entire array...
883 if (size == 0) return -1;
884 if (size<loopCnt) loopCnt = size;
885 //if we already have a valid clock quit
886
887 for (;i<8;++i)
888 if (clk[i] == *clock) return 0;
889
890 //get high and low peak
891 int peak, low;
892 getHiLo(dest, loopCnt, &peak, &low, 75, 75);
893
894 //test for large clean peaks
895 if (DetectCleanAskWave(dest, size, peak, low)==1){
896 uint16_t fcTest=0;
897 uint8_t mostFC=0;
898 fcTest=countFC(dest, size, &mostFC);
899 uint8_t fc1 = fcTest >> 8;
900 uint8_t fc2 = fcTest & 0xFF;
901
902 for (i=0; i<8; i++){
903 if (clk[i] == fc1) {
904 *clock=fc1;
905 return 0;
906 }
907 if (clk[i] == fc2) {
908 *clock=fc2;
909 return 0;
910 }
911 }
912 }
913
914 int ii;
915 int clkCnt;
916 int tol = 0;
917 int bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
918 int bestStart[]={0,0,0,0,0,0,0,0,0};
919 int errCnt=0;
920 //test each valid clock from smallest to greatest to see which lines up
921 for(clkCnt=0; clkCnt < 8; clkCnt++){
922 if (clk[clkCnt] == 32){
923 tol=1;
924 }else{
925 tol=0;
926 }
927 bestErr[clkCnt]=1000;
928 //try lining up the peaks by moving starting point (try first 256)
929 for (ii=0; ii < loopCnt; ii++){
930 if ((dest[ii] >= peak) || (dest[ii] <= low)){
931 errCnt=0;
932 // now that we have the first one lined up test rest of wave array
933 for (i=0; i<((int)((size-ii-tol)/clk[clkCnt])-1); ++i){
934 if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
935 }else if(dest[ii+(i*clk[clkCnt])-tol]>=peak || dest[ii+(i*clk[clkCnt])-tol]<=low){
936 }else if(dest[ii+(i*clk[clkCnt])+tol]>=peak || dest[ii+(i*clk[clkCnt])+tol]<=low){
937 }else{ //error no peak detected
938 errCnt++;
939 }
940 }
941 //if we found no errors then we can stop here
942 // this is correct one - return this clock
943 //PrintAndLog("DEBUG: clk %d, err %d, ii %d, i %d",clk[clkCnt],errCnt,ii,i);
944 if(errCnt==0 && clkCnt<6) {
945 *clock = clk[clkCnt];
946 return ii;
947 }
948 //if we found errors see if it is lowest so far and save it as best run
949 if(errCnt<bestErr[clkCnt]){
950 bestErr[clkCnt]=errCnt;
951 bestStart[clkCnt]=ii;
952 }
953 }
954 }
955 }
956 uint8_t iii=0;
957 uint8_t best=0;
958 for (iii=0; iii<8; ++iii){
959 if (bestErr[iii]<bestErr[best]){
960 if (bestErr[iii]==0) bestErr[iii]=1;
961 // current best bit to error ratio vs new bit to error ratio
962 if (((size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii]) ){
963 best = iii;
964 }
965 }
966 }
967 if (bestErr[best]>maxErr) return -1;
968 *clock=clk[best];
969 return bestStart[best];
970 }
971
972 //by marshmellow
973 //detect psk clock by reading each phase shift
974 // a phase shift is determined by measuring the sample length of each wave
975 int DetectPSKClock(uint8_t dest[], size_t size, int clock)
976 {
977 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
978 uint16_t loopCnt = 4096; //don't need to loop through entire array...
979 if (size == 0) return 0;
980 if (size<loopCnt) loopCnt = size;
981
982 //if we already have a valid clock quit
983 size_t i=1;
984 for (; i < 8; ++i)
985 if (clk[i] == clock) return clock;
986
987 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
988 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
989 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
990 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
991 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
992 countFC(dest, size, &fc);
993 //PrintAndLog("DEBUG: FC: %d",fc);
994
995 //find first full wave
996 for (i=0; i<loopCnt; i++){
997 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
998 if (waveStart == 0) {
999 waveStart = i+1;
1000 //PrintAndLog("DEBUG: waveStart: %d",waveStart);
1001 } else {
1002 waveEnd = i+1;
1003 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1004 waveLenCnt = waveEnd-waveStart;
1005 if (waveLenCnt > fc){
1006 firstFullWave = waveStart;
1007 fullWaveLen=waveLenCnt;
1008 break;
1009 }
1010 waveStart=0;
1011 }
1012 }
1013 }
1014 //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1015
1016 //test each valid clock from greatest to smallest to see which lines up
1017 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1018 lastClkBit = firstFullWave; //set end of wave as clock align
1019 waveStart = 0;
1020 errCnt=0;
1021 peakcnt=0;
1022 //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
1023
1024 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1025 //top edge of wave = start of new wave
1026 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1027 if (waveStart == 0) {
1028 waveStart = i+1;
1029 waveLenCnt=0;
1030 } else { //waveEnd
1031 waveEnd = i+1;
1032 waveLenCnt = waveEnd-waveStart;
1033 if (waveLenCnt > fc){
1034 //if this wave is a phase shift
1035 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, ii: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,ii+1,fc);
1036 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1037 peakcnt++;
1038 lastClkBit+=clk[clkCnt];
1039 } else if (i<lastClkBit+8){
1040 //noise after a phase shift - ignore
1041 } else { //phase shift before supposed to based on clock
1042 errCnt++;
1043 }
1044 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1045 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1046 }
1047 waveStart=i+1;
1048 }
1049 }
1050 }
1051 if (errCnt == 0){
1052 return clk[clkCnt];
1053 }
1054 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1055 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1056 }
1057 //all tested with errors
1058 //return the highest clk with the most peaks found
1059 uint8_t best=7;
1060 for (i=7; i>=1; i--){
1061 if (peaksdet[i] > peaksdet[best]) {
1062 best = i;
1063 }
1064 //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
1065 }
1066 return clk[best];
1067 }
1068
1069 //by marshmellow
1070 //detect nrz clock by reading #peaks vs no peaks(or errors)
1071 int DetectNRZClock(uint8_t dest[], size_t size, int clock)
1072 {
1073 int i=0;
1074 int clk[]={8,16,32,40,50,64,100,128,256};
1075 int loopCnt = 4096; //don't need to loop through entire array...
1076 if (size == 0) return 0;
1077 if (size<loopCnt) loopCnt = size;
1078
1079 //if we already have a valid clock quit
1080 for (; i < 8; ++i)
1081 if (clk[i] == clock) return clock;
1082
1083 //get high and low peak
1084 int peak, low;
1085 getHiLo(dest, loopCnt, &peak, &low, 75, 75);
1086
1087 //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low);
1088 int ii;
1089 uint8_t clkCnt;
1090 uint8_t tol = 0;
1091 int peakcnt=0;
1092 int peaksdet[]={0,0,0,0,0,0,0,0};
1093 int maxPeak=0;
1094 //test for large clipped waves
1095 for (i=0; i<loopCnt; i++){
1096 if (dest[i] >= peak || dest[i] <= low){
1097 peakcnt++;
1098 } else {
1099 if (peakcnt>0 && maxPeak < peakcnt){
1100 maxPeak = peakcnt;
1101 }
1102 peakcnt=0;
1103 }
1104 }
1105 peakcnt=0;
1106 //test each valid clock from smallest to greatest to see which lines up
1107 for(clkCnt=0; clkCnt < 8; ++clkCnt){
1108 //ignore clocks smaller than largest peak
1109 if (clk[clkCnt]<maxPeak) continue;
1110
1111 //try lining up the peaks by moving starting point (try first 256)
1112 for (ii=0; ii< loopCnt; ++ii){
1113 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1114 peakcnt=0;
1115 // now that we have the first one lined up test rest of wave array
1116 for (i=0; i < ((int)((size-ii-tol)/clk[clkCnt])-1); ++i){
1117 if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){
1118 peakcnt++;
1119 }
1120 }
1121 if(peakcnt>peaksdet[clkCnt]) {
1122 peaksdet[clkCnt]=peakcnt;
1123 }
1124 }
1125 }
1126 }
1127 int iii=7;
1128 int best=0;
1129 for (iii=7; iii > 0; iii--){
1130 if (peaksdet[iii] > peaksdet[best]){
1131 best = iii;
1132 }
1133 //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]);
1134 }
1135 return clk[best];
1136 }
1137
1138 // by marshmellow
1139 // convert psk1 demod to psk2 demod
1140 // only transition waves are 1s
1141 void psk1TOpsk2(uint8_t *BitStream, size_t size)
1142 {
1143 size_t i=1;
1144 uint8_t lastBit=BitStream[0];
1145 for (; i<size; i++){
1146 if (BitStream[i]==77){
1147 //ignore errors
1148 } else if (lastBit!=BitStream[i]){
1149 lastBit=BitStream[i];
1150 BitStream[i]=1;
1151 } else {
1152 BitStream[i]=0;
1153 }
1154 }
1155 return;
1156 }
1157
1158 // by marshmellow
1159 // convert psk2 demod to psk1 demod
1160 // from only transition waves are 1s to phase shifts change bit
1161 void psk2TOpsk1(uint8_t *BitStream, size_t size)
1162 {
1163 uint8_t phase=0;
1164 for (size_t i=0; i<size; i++){
1165 if (BitStream[i]==1){
1166 phase ^=1;
1167 }
1168 BitStream[i]=phase;
1169 }
1170 return;
1171 }
1172
1173 // redesigned by marshmellow adjusted from existing decode functions
1174 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1175 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1176 {
1177 //26 bit 40134 format (don't know other formats)
1178 int i;
1179 int long_wait=29;//29 leading zeros in format
1180 int start;
1181 int first = 0;
1182 int first2 = 0;
1183 int bitCnt = 0;
1184 int ii;
1185 // Finding the start of a UID
1186 for (start = 0; start <= *size - 250; start++) {
1187 first = bitStream[start];
1188 for (i = start; i < start + long_wait; i++) {
1189 if (bitStream[i] != first) {
1190 break;
1191 }
1192 }
1193 if (i == (start + long_wait)) {
1194 break;
1195 }
1196 }
1197 if (start == *size - 250 + 1) {
1198 // did not find start sequence
1199 return -1;
1200 }
1201 // Inverting signal if needed
1202 if (first == 1) {
1203 for (i = start; i < *size; i++) {
1204 bitStream[i] = !bitStream[i];
1205 }
1206 *invert = 1;
1207 }else *invert=0;
1208
1209 int iii;
1210 //found start once now test length by finding next one
1211 for (ii=start+29; ii <= *size - 250; ii++) {
1212 first2 = bitStream[ii];
1213 for (iii = ii; iii < ii + long_wait; iii++) {
1214 if (bitStream[iii] != first2) {
1215 break;
1216 }
1217 }
1218 if (iii == (ii + long_wait)) {
1219 break;
1220 }
1221 }
1222 if (ii== *size - 250 + 1){
1223 // did not find second start sequence
1224 return -2;
1225 }
1226 bitCnt=ii-start;
1227
1228 // Dumping UID
1229 i = start;
1230 for (ii = 0; ii < bitCnt; ii++) {
1231 bitStream[ii] = bitStream[i++];
1232 }
1233 *size=bitCnt;
1234 return 1;
1235 }
1236
1237 // by marshmellow - demodulate NRZ wave (both similar enough)
1238 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1239 // there probably is a much simpler way to do this....
1240 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int maxErr)
1241 {
1242 if (justNoise(dest, *size)) return -1;
1243 *clk = DetectNRZClock(dest, *size, *clk);
1244 if (*clk==0) return -2;
1245 uint32_t i;
1246 int high, low, ans;
1247 ans = getHiLo(dest, 1260, &high, &low, 75, 75); //25% fuzz on high 25% fuzz on low
1248 if (ans<1) return -2; //just noise
1249 uint32_t gLen = 256;
1250 if (gLen>*size) gLen = *size;
1251 int lastBit = 0; //set first clock check
1252 uint32_t bitnum = 0; //output counter
1253 uint8_t tol = 1; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
1254 uint32_t iii = 0;
1255 uint16_t errCnt =0;
1256 uint16_t MaxBits = 1000;
1257 uint32_t bestErrCnt = maxErr+1;
1258 uint32_t bestPeakCnt = 0;
1259 uint32_t bestPeakStart=0;
1260 uint8_t curBit=0;
1261 uint8_t bitHigh=0;
1262 uint8_t errBitHigh=0;
1263 uint16_t peakCnt=0;
1264 uint8_t ignoreWindow=4;
1265 uint8_t ignoreCnt=ignoreWindow; //in case of noice near peak
1266 //loop to find first wave that works - align to clock
1267 for (iii=0; iii < gLen; ++iii){
1268 if ((dest[iii]>=high) || (dest[iii]<=low)){
1269 lastBit=iii-*clk;
1270 peakCnt=0;
1271 errCnt=0;
1272 bitnum=0;
1273 //loop through to see if this start location works
1274 for (i = iii; i < *size; ++i) {
1275 //if we found a high bar and we are at a clock bit
1276 if ((dest[i]>=high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
1277 bitHigh=1;
1278 lastBit+=*clk;
1279 bitnum++;
1280 peakCnt++;
1281 errBitHigh=0;
1282 ignoreCnt=ignoreWindow;
1283 //else if low bar found and we are at a clock point
1284 }else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
1285 bitHigh=1;
1286 lastBit+=*clk;
1287 bitnum++;
1288 peakCnt++;
1289 errBitHigh=0;
1290 ignoreCnt=ignoreWindow;
1291 //else if no bars found
1292 }else if(dest[i] < high && dest[i] > low) {
1293 if (ignoreCnt==0){
1294 bitHigh=0;
1295 if (errBitHigh==1){
1296 errCnt++;
1297 }
1298 errBitHigh=0;
1299 } else {
1300 ignoreCnt--;
1301 }
1302 //if we are past a clock point
1303 if (i >= lastBit+*clk+tol){ //clock val
1304 lastBit+=*clk;
1305 bitnum++;
1306 }
1307 //else if bar found but we are not at a clock bit and we did not just have a clock bit
1308 }else if ((dest[i]>=high || dest[i]<=low) && (i<lastBit+*clk-tol || i>lastBit+*clk+tol) && (bitHigh==0)){
1309 //error bar found no clock...
1310 errBitHigh=1;
1311 }
1312 if (bitnum>=MaxBits) break;
1313 }
1314 //we got more than 64 good bits and not all errors
1315 if (bitnum > (64) && (errCnt <= (maxErr))) {
1316 //possible good read
1317 if (errCnt == 0){
1318 //bestStart = iii;
1319 bestErrCnt = errCnt;
1320 bestPeakCnt = peakCnt;
1321 bestPeakStart = iii;
1322 break; //great read - finish
1323 }
1324 if (errCnt < bestErrCnt){ //set this as new best run
1325 bestErrCnt = errCnt;
1326 //bestStart = iii;
1327 }
1328 if (peakCnt > bestPeakCnt){
1329 bestPeakCnt=peakCnt;
1330 bestPeakStart=iii;
1331 }
1332 }
1333 }
1334 }
1335 //PrintAndLog("DEBUG: bestErrCnt: %d, maxErr: %d, bestStart: %d, bestPeakCnt: %d, bestPeakStart: %d",bestErrCnt,maxErr,bestStart,bestPeakCnt,bestPeakStart);
1336 if (bestErrCnt <= maxErr){
1337 //best run is good enough set to best run and set overwrite BinStream
1338 iii=bestPeakStart;
1339 lastBit=bestPeakStart-*clk;
1340 bitnum=0;
1341 for (i = iii; i < *size; ++i) {
1342 //if we found a high bar and we are at a clock bit
1343 if ((dest[i] >= high ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
1344 bitHigh=1;
1345 lastBit+=*clk;
1346 curBit=1-*invert;
1347 dest[bitnum]=curBit;
1348 bitnum++;
1349 errBitHigh=0;
1350 ignoreCnt=ignoreWindow;
1351 //else if low bar found and we are at a clock point
1352 }else if ((dest[i]<=low ) && (i>=lastBit+*clk-tol && i<=lastBit+*clk+tol)){
1353 bitHigh=1;
1354 lastBit+=*clk;
1355 curBit=*invert;
1356 dest[bitnum]=curBit;
1357 bitnum++;
1358 errBitHigh=0;
1359 ignoreCnt=ignoreWindow;
1360 //else if no bars found
1361 }else if(dest[i]<high && dest[i]>low) {
1362 if (ignoreCnt==0){
1363 bitHigh=0;
1364 //if peak is done was it an error peak?
1365 if (errBitHigh==1){
1366 dest[bitnum]=77;
1367 bitnum++;
1368 errCnt++;
1369 }
1370 errBitHigh=0;
1371 } else {
1372 ignoreCnt--;
1373 }
1374 //if we are past a clock point
1375 if (i>=lastBit+*clk+tol){ //clock val
1376 lastBit+=*clk;
1377 dest[bitnum]=curBit;
1378 bitnum++;
1379 }
1380 //else if bar found but we are not at a clock bit and we did not just have a clock bit
1381 }else if ((dest[i]>=high || dest[i]<=low) && ((i<lastBit+*clk-tol) || (i>lastBit+*clk+tol)) && (bitHigh==0)){
1382 //error bar found no clock...
1383 errBitHigh=1;
1384 }
1385 if (bitnum >= MaxBits) break;
1386 }
1387 *size=bitnum;
1388 } else{
1389 *size=bitnum;
1390 return -1;
1391 }
1392
1393 if (bitnum>16){
1394 *size=bitnum;
1395 } else return -1;
1396 return errCnt;
1397 }
1398
1399 //by marshmellow
1400 //detects the bit clock for FSK given the high and low Field Clocks
1401 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1402 {
1403 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1404 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1405 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1406 uint8_t rfLensFnd = 0;
1407 uint8_t lastFCcnt=0;
1408 uint32_t fcCounter = 0;
1409 uint16_t rfCounter = 0;
1410 uint8_t firstBitFnd = 0;
1411 size_t i;
1412 if (size == 0) return 0;
1413
1414 uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1415 rfLensFnd=0;
1416 fcCounter=0;
1417 rfCounter=0;
1418 firstBitFnd=0;
1419 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
1420 // prime i to first up transition
1421 for (i = 1; i < size-1; i++)
1422 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1423 break;
1424
1425 for (; i < size-1; i++){
1426 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]){
1427 // new peak
1428 fcCounter++;
1429 rfCounter++;
1430 // if we got less than the small fc + tolerance then set it to the small fc
1431 if (fcCounter < fcLow+fcTol)
1432 fcCounter = fcLow;
1433 else //set it to the large fc
1434 fcCounter = fcHigh;
1435
1436 //look for bit clock (rf/xx)
1437 if ((fcCounter<lastFCcnt || fcCounter>lastFCcnt)){
1438 //not the same size as the last wave - start of new bit sequence
1439
1440 if (firstBitFnd>1){ //skip first wave change - probably not a complete bit
1441 for (int ii=0; ii<15; ii++){
1442 if (rfLens[ii]==rfCounter){
1443 rfCnts[ii]++;
1444 rfCounter=0;
1445 break;
1446 }
1447 }
1448 if (rfCounter>0 && rfLensFnd<15){
1449 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1450 rfCnts[rfLensFnd]++;
1451 rfLens[rfLensFnd++]=rfCounter;
1452 }
1453 } else {
1454 firstBitFnd++;
1455 }
1456 rfCounter=0;
1457 lastFCcnt=fcCounter;
1458 }
1459 fcCounter=0;
1460 } else {
1461 // count sample
1462 fcCounter++;
1463 rfCounter++;
1464 }
1465 }
1466 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1467
1468 for (i=0; i<15; i++){
1469 //PrintAndLog("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]);
1470 //get highest 2 RF values (might need to get more values to compare or compare all?)
1471 if (rfCnts[i]>rfCnts[rfHighest]){
1472 rfHighest3=rfHighest2;
1473 rfHighest2=rfHighest;
1474 rfHighest=i;
1475 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1476 rfHighest3=rfHighest2;
1477 rfHighest2=i;
1478 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1479 rfHighest3=i;
1480 }
1481 }
1482 // set allowed clock remainder tolerance to be 1 large field clock length+1
1483 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1484 uint8_t tol1 = fcHigh+1;
1485
1486 //PrintAndLog("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
1487
1488 // loop to find the highest clock that has a remainder less than the tolerance
1489 // compare samples counted divided by
1490 int ii=7;
1491 for (; ii>=0; ii--){
1492 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1493 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1494 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
1495 break;
1496 }
1497 }
1498 }
1499 }
1500
1501 if (ii<0) return 0; // oops we went too far
1502
1503 return clk[ii];
1504 }
1505
1506 //by marshmellow
1507 //countFC is to detect the field clock lengths.
1508 //counts and returns the 2 most common wave lengths
1509 //mainly used for FSK field clock detection
1510 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t *mostFC)
1511 {
1512 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0};
1513 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
1514 uint8_t fcLensFnd = 0;
1515 uint8_t lastFCcnt=0;
1516 uint32_t fcCounter = 0;
1517 size_t i;
1518 if (size == 0) return 0;
1519
1520 // prime i to first up transition
1521 for (i = 1; i < size-1; i++)
1522 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1523 break;
1524
1525 for (; i < size-1; i++){
1526 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1527 // new up transition
1528 fcCounter++;
1529
1530 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1531 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1532 //if odd and not rc/5 add one (for when we get a fc 9 instead of 10)
1533 if ((fcCounter==9 && fcCounter & 1) || fcCounter==4) fcCounter++;
1534
1535 // save last field clock count (fc/xx)
1536 // find which fcLens to save it to:
1537 for (int ii=0; ii<10; ii++){
1538 if (fcLens[ii]==fcCounter){
1539 fcCnts[ii]++;
1540 fcCounter=0;
1541 break;
1542 }
1543 }
1544 if (fcCounter>0 && fcLensFnd<10){
1545 //add new fc length
1546 fcCnts[fcLensFnd]++;
1547 fcLens[fcLensFnd++]=fcCounter;
1548 }
1549 fcCounter=0;
1550 } else {
1551 // count sample
1552 fcCounter++;
1553 }
1554 }
1555
1556 uint8_t best1=9, best2=9, best3=9;
1557 uint16_t maxCnt1=0;
1558 // go through fclens and find which ones are bigest 2
1559 for (i=0; i<10; i++){
1560 // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d",fcLens[i],fcCnts[i],errCnt);
1561 // get the 3 best FC values
1562 if (fcCnts[i]>maxCnt1) {
1563 best3=best2;
1564 best2=best1;
1565 maxCnt1=fcCnts[i];
1566 best1=i;
1567 } else if(fcCnts[i]>fcCnts[best2]){
1568 best3=best2;
1569 best2=i;
1570 } else if(fcCnts[i]>fcCnts[best3]){
1571 best3=i;
1572 }
1573 }
1574 uint8_t fcH=0, fcL=0;
1575 if (fcLens[best1]>fcLens[best2]){
1576 fcH=fcLens[best1];
1577 fcL=fcLens[best2];
1578 } else{
1579 fcH=fcLens[best2];
1580 fcL=fcLens[best1];
1581 }
1582
1583 *mostFC=fcLens[best1];
1584 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1585
1586 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
1587 // PrintAndLog("DEBUG: Best %d best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]);
1588
1589 return fcs;
1590 }
1591
1592 //by marshmellow
1593 //countPSK_FC is to detect the psk carrier clock length.
1594 //counts and returns the 1 most common wave length
1595 uint8_t countPSK_FC(uint8_t *BitStream, size_t size)
1596 {
1597 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0};
1598 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0};
1599 uint8_t fcLensFnd = 0;
1600 uint32_t fcCounter = 0;
1601 size_t i;
1602 if (size == 0) return 0;
1603
1604 // prime i to first up transition
1605 for (i = 1; i < size-1; i++)
1606 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1607 break;
1608
1609 for (; i < size-1; i++){
1610 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1611 // new up transition
1612 fcCounter++;
1613
1614 // save last field clock count (fc/xx)
1615 // find which fcLens to save it to:
1616 for (int ii=0; ii<10; ii++){
1617 if (fcLens[ii]==fcCounter){
1618 fcCnts[ii]++;
1619 fcCounter=0;
1620 break;
1621 }
1622 }
1623 if (fcCounter>0 && fcLensFnd<10){
1624 //add new fc length
1625 fcCnts[fcLensFnd]++;
1626 fcLens[fcLensFnd++]=fcCounter;
1627 }
1628 fcCounter=0;
1629 } else {
1630 // count sample
1631 fcCounter++;
1632 }
1633 }
1634
1635 uint8_t best1=9;
1636 uint16_t maxCnt1=0;
1637 // go through fclens and find which ones are bigest
1638 for (i=0; i<10; i++){
1639 //PrintAndLog("DEBUG: FC %d, Cnt %d",fcLens[i],fcCnts[i]);
1640 // get the best FC value
1641 if (fcCnts[i]>maxCnt1) {
1642 maxCnt1=fcCnts[i];
1643 best1=i;
1644 }
1645 }
1646 return fcLens[best1];
1647 }
1648
1649 //by marshmellow - demodulate PSK1 wave
1650 //uses wave lengths (# Samples)
1651 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1652 {
1653 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1654 if (size == 0) return -1;
1655 if (*size<loopCnt) loopCnt = *size;
1656
1657 uint8_t curPhase = *invert;
1658 size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1659 uint8_t fc=0, fullWaveLen=0, tol=1;
1660 uint16_t errCnt=0, waveLenCnt=0;
1661 fc = countPSK_FC(dest, *size);
1662 if (fc!=2 && fc!=4 && fc!=8) return -1;
1663 //PrintAndLog("DEBUG: FC: %d",fc);
1664 *clock = DetectPSKClock(dest, *size, *clock);
1665 if (*clock==0) return -1;
1666 int avgWaveVal=0, lastAvgWaveVal=0;
1667 //find first phase shift
1668 for (i=0; i<loopCnt; i++){
1669 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1670 waveEnd = i+1;
1671 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1672 waveLenCnt = waveEnd-waveStart;
1673 if (waveLenCnt > fc && waveStart > fc){ //not first peak and is a large wave
1674 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1675 firstFullWave = waveStart;
1676 fullWaveLen=waveLenCnt;
1677 //if average wave value is > graph 0 then it is an up wave or a 1
1678 if (lastAvgWaveVal > 123) curPhase^=1; //fudge graph 0 a little 123 vs 128
1679 break;
1680 }
1681 waveStart = i+1;
1682 avgWaveVal = 0;
1683 }
1684 avgWaveVal+=dest[i+2];
1685 }
1686 //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1687 lastClkBit = firstFullWave; //set start of wave as clock align
1688 //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
1689 waveStart = 0;
1690 errCnt=0;
1691 size_t numBits=0;
1692 //set skipped bits
1693 memset(dest+numBits,curPhase^1,firstFullWave / *clock);
1694 numBits += (firstFullWave / *clock);
1695 dest[numBits++] = curPhase; //set first read bit
1696 for (i = firstFullWave+fullWaveLen-1; i < *size-3; i++){
1697 //top edge of wave = start of new wave
1698 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1699 if (waveStart == 0) {
1700 waveStart = i+1;
1701 waveLenCnt=0;
1702 avgWaveVal = dest[i+1];
1703 } else { //waveEnd
1704 waveEnd = i+1;
1705 waveLenCnt = waveEnd-waveStart;
1706 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1707 if (waveLenCnt > fc){
1708 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1709 //if this wave is a phase shift
1710 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1711 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1712 curPhase^=1;
1713 dest[numBits++] = curPhase;
1714 lastClkBit += *clock;
1715 } else if (i<lastClkBit+10+fc){
1716 //noise after a phase shift - ignore
1717 } else { //phase shift before supposed to based on clock
1718 errCnt++;
1719 dest[numBits++] = 77;
1720 }
1721 } else if (i+1 > lastClkBit + *clock + tol + fc){
1722 lastClkBit += *clock; //no phase shift but clock bit
1723 dest[numBits++] = curPhase;
1724 }
1725 avgWaveVal=0;
1726 waveStart=i+1;
1727 }
1728 }
1729 avgWaveVal+=dest[i+1];
1730 }
1731 *size = numBits;
1732 return errCnt;
1733 }
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