49838f5e2be22e694015a181a0e36438c74b4561
[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 - by marshmellow, holiman, iceman and
9 // many others who came before
10 //
11 // NOTES:
12 // LF Demod functions are placed here to allow the flexability to use client or
13 // device side. Most BUT NOT ALL of these functions are currenlty safe for
14 // device side use currently. (DetectST for example...)
15 //
16 // There are likely many improvements to the code that could be made, please
17 // make suggestions...
18 //
19 // we tried to include author comments so any questions could be directed to
20 // the source.
21 //
22 // There are 4 main sections of code below:
23 // Utilities Section:
24 // for general utilities used by multiple other functions
25 // Clock / Bitrate Detection Section:
26 // for clock detection functions for each modulation
27 // Modulation Demods &/or Decoding Section:
28 // for main general modulation demodulating and encoding decoding code.
29 // Tag format detection section:
30 // for detection of specific tag formats within demodulated data
31 //
32 // marshmellow
33 //-----------------------------------------------------------------------------
34
35 #include <string.h> // for memset, memcmp and size_t
36 #include "lfdemod.h"
37 #include <stdint.h> // for uint_32+
38 #include <stdbool.h> // for bool
39 #include "parity.h" // for parity test
40
41 //**********************************************************************************************
42 //---------------------------------Utilities Section--------------------------------------------
43 //**********************************************************************************************
44 #define LOWEST_DEFAULT_CLOCK 32
45 #define FSK_PSK_THRESHOLD 123
46
47 //to allow debug print calls when used not on device
48 void dummy(char *fmt, ...){}
49 #ifndef ON_DEVICE
50 #include "ui.h"
51 #include "cmdparser.h"
52 #include "cmddata.h"
53 #define prnt PrintAndLog
54 #else
55 uint8_t g_debugMode=0;
56 #define prnt dummy
57 #endif
58
59 uint8_t justNoise(uint8_t *BitStream, size_t size) {
60 //test samples are not just noise
61 uint8_t justNoise1 = 1;
62 for(size_t idx=0; idx < size && justNoise1 ;idx++){
63 justNoise1 = BitStream[idx] < FSK_PSK_THRESHOLD;
64 }
65 return justNoise1;
66 }
67
68 //by marshmellow
69 //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
70 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) {
71 *high=0;
72 *low=255;
73 // get high and low thresholds
74 for (size_t i=0; i < size; i++){
75 if (BitStream[i] > *high) *high = BitStream[i];
76 if (BitStream[i] < *low) *low = BitStream[i];
77 }
78 if (*high < FSK_PSK_THRESHOLD) return -1; // just noise
79 *high = ((*high-128)*fuzzHi + 12800)/100;
80 *low = ((*low-128)*fuzzLo + 12800)/100;
81 return 1;
82 }
83
84 // by marshmellow
85 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
86 // returns 1 if passed
87 bool parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
88 return oddparity32(bits) ^ pType;
89 }
90
91 // by marshmellow
92 // takes a array of binary values, start position, length of bits per parity (includes parity bit - MAX 32),
93 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
94 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) {
95 uint32_t parityWd = 0;
96 size_t bitCnt = 0;
97 for (int word = 0; word < (bLen); word+=pLen) {
98 for (int bit=0; bit < pLen; bit++) {
99 if (word+bit >= bLen) break;
100 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
101 BitStream[bitCnt++] = (BitStream[startIdx+word+bit]);
102 }
103 if (word+pLen > bLen) break;
104
105 bitCnt--; // overwrite parity with next data
106 // if parity fails then return 0
107 switch (pType) {
108 case 3: if (BitStream[bitCnt]==1) {return 0;} break; //should be 0 spacer bit
109 case 2: if (BitStream[bitCnt]==0) {return 0;} break; //should be 1 spacer bit
110 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
111 }
112 parityWd = 0;
113 }
114 // if we got here then all the parities passed
115 //return size
116 return bitCnt;
117 }
118
119 // by marshmellow
120 // takes a array of binary values, length of bits per parity (includes parity bit),
121 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
122 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
123 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) {
124 uint32_t parityWd = 0;
125 size_t j = 0, bitCnt = 0;
126 for (int word = 0; word < sourceLen; word+=pLen-1) {
127 for (int bit=0; bit < pLen-1; bit++){
128 parityWd = (parityWd << 1) | BitSource[word+bit];
129 dest[j++] = (BitSource[word+bit]);
130 }
131 // if parity fails then return 0
132 switch (pType) {
133 case 3: dest[j++]=0; break; // marker bit which should be a 0
134 case 2: dest[j++]=1; break; // marker bit which should be a 1
135 default:
136 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
137 break;
138 }
139 bitCnt += pLen;
140 parityWd = 0;
141 }
142 // if we got here then all the parities passed
143 //return ID start index and size
144 return bitCnt;
145 }
146
147 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) {
148 uint32_t num = 0;
149 for(int i = 0 ; i < numbits ; i++)
150 {
151 num = (num << 1) | (*src);
152 src++;
153 }
154 return num;
155 }
156
157 //least significant bit first
158 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) {
159 uint32_t num = 0;
160 for(int i = 0 ; i < numbits ; i++)
161 {
162 num = (num << 1) | *(src + (numbits-(i+1)));
163 }
164 return num;
165 }
166
167 // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
168 // fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
169 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
170 // Sanity check. If preamble length is bigger than bitstream length.
171 if ( *size <= pLen ) return false;
172
173 uint8_t foundCnt = 0;
174 for (size_t idx = 0; idx < *size - pLen; idx++) {
175 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
176 //first index found
177 foundCnt++;
178 if (foundCnt == 1) {
179 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
180 *startIdx = idx;
181 if (findone) return true;
182 } else if (foundCnt == 2) {
183 *size = idx - *startIdx;
184 return true;
185 }
186 }
187 }
188 return false;
189 }
190
191 //by marshmellow
192 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
193 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) {
194 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
195 }
196
197 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
198 size_t findModStart(uint8_t dest[], size_t size, uint8_t expWaveSize) {
199 size_t i = 0;
200 size_t waveSizeCnt = 0;
201 uint8_t thresholdCnt = 0;
202 bool isAboveThreshold = dest[i++] >= FSK_PSK_THRESHOLD;
203 for (; i < size-20; i++ ) {
204 if(dest[i] < FSK_PSK_THRESHOLD && isAboveThreshold) {
205 thresholdCnt++;
206 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
207 isAboveThreshold = false;
208 waveSizeCnt = 0;
209 } else if (dest[i] >= FSK_PSK_THRESHOLD && !isAboveThreshold) {
210 thresholdCnt++;
211 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
212 isAboveThreshold = true;
213 waveSizeCnt = 0;
214 } else {
215 waveSizeCnt++;
216 }
217 if (thresholdCnt > 10) break;
218 }
219 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
220 return i;
221 }
222
223 int getClosestClock(int testclk) {
224 uint8_t fndClk[] = {8,16,32,40,50,64,128};
225
226 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++)
227 if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1)
228 return fndClk[clkCnt];
229
230 return 0;
231 }
232
233 void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) {
234 while ((samples[*i] > low) && (*i < size))
235 *i+=1;
236 }
237
238 void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) {
239 while ((samples[*i] < high) && (*i < size))
240 *i+=1;
241 }
242
243 // load wave counters
244 bool loadWaveCounters(uint8_t samples[], size_t size, int lowToLowWaveLen[], int highToLowWaveLen[], int *waveCnt, int *skip, int *minClk, int *high, int *low) {
245 size_t i=0, firstLow, firstHigh;
246 size_t testsize = (size < 512) ? size : 512;
247
248 if ( getHiLo(samples, testsize, high, low, 80, 80) == -1 ) {
249 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
250 return false; //just noise
251 }
252
253 // get to first full low to prime loop and skip incomplete first pulse
254 getNextHigh(samples, size, *high, &i);
255 getNextLow(samples, size, *low, &i);
256 *skip = i;
257
258 // populate tmpbuff buffer with pulse lengths
259 while (i < size) {
260 // measure from low to low
261 firstLow = i;
262 //find first high point for this wave
263 getNextHigh(samples, size, *high, &i);
264 firstHigh = i;
265
266 getNextLow(samples, size, *low, &i);
267
268 if (*waveCnt >= (size/LOWEST_DEFAULT_CLOCK))
269 break;
270
271 highToLowWaveLen[*waveCnt] = i - firstHigh; //first high to first low
272 lowToLowWaveLen[*waveCnt] = i - firstLow;
273 *waveCnt += 1;
274 if (i-firstLow < *minClk && i < size) {
275 *minClk = i - firstLow;
276 }
277 }
278 return true;
279 }
280
281 size_t pskFindFirstPhaseShift(uint8_t samples[], size_t size, uint8_t *curPhase, size_t waveStart, uint16_t fc, uint16_t *fullWaveLen) {
282 uint16_t loopCnt = (size+3 < 4096) ? size : 4096; //don't need to loop through entire array...
283
284 uint16_t avgWaveVal=0, lastAvgWaveVal=0;
285 size_t i = waveStart, waveEnd, waveLenCnt, firstFullWave;
286 for (; i<loopCnt; i++) {
287 // find peak // was "samples[i] + fc" but why? must have been used to weed out some wave error... removed..
288 if (samples[i] < samples[i+1] && samples[i+1] >= samples[i+2]){
289 waveEnd = i+1;
290 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u", waveEnd, waveStart);
291 waveLenCnt = waveEnd-waveStart;
292 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+8)){ //not first peak and is a large wave but not out of whack
293 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
294 firstFullWave = waveStart;
295 *fullWaveLen = waveLenCnt;
296 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
297 if (lastAvgWaveVal > FSK_PSK_THRESHOLD) *curPhase ^= 1;
298 return firstFullWave;
299 }
300 waveStart = i+1;
301 avgWaveVal = 0;
302 }
303 avgWaveVal += samples[i+2];
304 }
305 return 0;
306 }
307
308 //by marshmellow
309 //amplify based on ask edge detection - not accurate enough to use all the time
310 void askAmp(uint8_t *BitStream, size_t size) {
311 uint8_t Last = 128;
312 for(size_t i = 1; i<size; i++){
313 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
314 Last = 255;
315 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
316 Last = 0;
317
318 BitStream[i-1] = Last;
319 }
320 return;
321 }
322
323 uint32_t manchesterEncode2Bytes(uint16_t datain) {
324 uint32_t output = 0;
325 uint8_t curBit = 0;
326 for (uint8_t i=0; i<16; i++) {
327 curBit = (datain >> (15-i) & 1);
328 output |= (1<<(((15-i)*2)+curBit));
329 }
330 return output;
331 }
332
333 //by marshmellow
334 //encode binary data into binary manchester
335 //NOTE: BitStream must have triple the size of "size" available in memory to do the swap
336 int ManchesterEncode(uint8_t *BitStream, size_t size) {
337 //allow up to 4K out (means BitStream must be at least 2048+4096 to handle the swap)
338 size = (size>2048) ? 2048 : size;
339 size_t modIdx = size;
340 size_t i;
341 for (size_t idx=0; idx < size; idx++){
342 BitStream[idx+modIdx++] = BitStream[idx];
343 BitStream[idx+modIdx++] = BitStream[idx]^1;
344 }
345 for (i=0; i<(size*2); i++){
346 BitStream[i] = BitStream[i+size];
347 }
348 return i;
349 }
350
351 // by marshmellow
352 // to detect a wave that has heavily clipped (clean) samples
353 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) {
354 bool allArePeaks = true;
355 uint16_t cntPeaks=0;
356 size_t loopEnd = 512+160;
357 if (loopEnd > size) loopEnd = size;
358 for (size_t i=160; i<loopEnd; i++){
359 if (dest[i]>low && dest[i]<high)
360 allArePeaks = false;
361 else
362 cntPeaks++;
363 }
364 if (!allArePeaks){
365 if (cntPeaks > 300) return true;
366 }
367 return allArePeaks;
368 }
369
370 //**********************************************************************************************
371 //-------------------Clock / Bitrate Detection Section------------------------------------------
372 //**********************************************************************************************
373
374 // by marshmellow
375 // to help detect clocks on heavily clipped samples
376 // based on count of low to low
377 int DetectStrongAskClock(uint8_t dest[], size_t size, int high, int low, int *clock) {
378 size_t startwave;
379 size_t i = 100;
380 size_t minClk = 255;
381 int shortestWaveIdx = 0;
382 // get to first full low to prime loop and skip incomplete first pulse
383 getNextHigh(dest, size, high, &i);
384 getNextLow(dest, size, low, &i);
385
386 // loop through all samples
387 while (i < size) {
388 // measure from low to low
389 startwave = i;
390
391 getNextHigh(dest, size, high, &i);
392 getNextLow(dest, size, low, &i);
393 //get minimum measured distance
394 if (i-startwave < minClk && i < size) {
395 minClk = i - startwave;
396 shortestWaveIdx = startwave;
397 }
398 }
399 // set clock
400 if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk);
401 *clock = getClosestClock(minClk);
402 if (*clock == 0)
403 return 0;
404
405 return shortestWaveIdx;
406 }
407
408 // by marshmellow
409 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
410 // maybe somehow adjust peak trimming value based on samples to fix?
411 // return start index of best starting position for that clock and return clock (by reference)
412 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) {
413 size_t i=1;
414 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
415 uint8_t clkEnd = 9;
416 uint8_t loopCnt = 255; //don't need to loop through entire array...
417 if (size <= loopCnt+60) return -1; //not enough samples
418 size -= 60; //sometimes there is a strange end wave - filter out this....
419 //if we already have a valid clock
420 uint8_t clockFnd=0;
421 for (;i<clkEnd;++i)
422 if (clk[i] == *clock) clockFnd = i;
423 //clock found but continue to find best startpos
424
425 //get high and low peak
426 int peak, low;
427 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
428
429 //test for large clean peaks
430 if (!clockFnd){
431 if (DetectCleanAskWave(dest, size, peak, low)==1){
432 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
433 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
434 if (ans > 0) {
435 return ans; //return shortest wave start position
436 }
437 }
438 }
439 uint8_t ii;
440 uint8_t clkCnt, tol = 0;
441 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
442 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
443 size_t errCnt = 0;
444 size_t arrLoc, loopEnd;
445
446 if (clockFnd>0) {
447 clkCnt = clockFnd;
448 clkEnd = clockFnd+1;
449 }
450 else clkCnt=1;
451
452 //test each valid clock from smallest to greatest to see which lines up
453 for(; clkCnt < clkEnd; clkCnt++){
454 if (clk[clkCnt] <= 32){
455 tol=1;
456 }else{
457 tol=0;
458 }
459 //if no errors allowed - keep start within the first clock
460 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
461 bestErr[clkCnt]=1000;
462 //try lining up the peaks by moving starting point (try first few clocks)
463 for (ii=0; ii < loopCnt; ii++){
464 if (dest[ii] < peak && dest[ii] > low) continue;
465
466 errCnt=0;
467 // now that we have the first one lined up test rest of wave array
468 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
469 for (i=0; i < loopEnd; ++i){
470 arrLoc = ii + (i * clk[clkCnt]);
471 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
472 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
473 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
474 }else{ //error no peak detected
475 errCnt++;
476 }
477 }
478 //if we found no errors then we can stop here and a low clock (common clocks)
479 // this is correct one - return this clock
480 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
481 if(errCnt==0 && clkCnt<7) {
482 if (!clockFnd) *clock = clk[clkCnt];
483 return ii;
484 }
485 //if we found errors see if it is lowest so far and save it as best run
486 if(errCnt<bestErr[clkCnt]){
487 bestErr[clkCnt]=errCnt;
488 bestStart[clkCnt]=ii;
489 }
490 }
491 }
492 uint8_t iii;
493 uint8_t best=0;
494 for (iii=1; iii<clkEnd; ++iii){
495 if (bestErr[iii] < bestErr[best]){
496 if (bestErr[iii] == 0) bestErr[iii]=1;
497 // current best bit to error ratio vs new bit to error ratio
498 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
499 best = iii;
500 }
501 }
502 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d",clk[iii],bestErr[iii],clk[best],bestStart[best]);
503 }
504 if (!clockFnd) *clock = clk[best];
505 return bestStart[best];
506 }
507
508 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
509 //find shortest transition from high to low
510 size_t i = 0;
511 size_t transition1 = 0;
512 int lowestTransition = 255;
513 bool lastWasHigh = false;
514
515 //find first valid beginning of a high or low wave
516 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
517 ++i;
518 while ((dest[i] < peak && dest[i] > low) && (i < size))
519 ++i;
520 lastWasHigh = (dest[i] >= peak);
521
522 if (i==size) return 0;
523 transition1 = i;
524
525 for (;i < size; i++) {
526 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
527 lastWasHigh = (dest[i] >= peak);
528 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
529 transition1 = i;
530 }
531 }
532 if (lowestTransition == 255) lowestTransition = 0;
533 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
534 return lowestTransition;
535 }
536
537 //by marshmellow
538 //detect nrz clock by reading #peaks vs no peaks(or errors)
539 int DetectNRZClock(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
540 size_t i=0;
541 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
542 size_t loopCnt = 4096; //don't need to loop through entire array...
543 if (size == 0) return 0;
544 if (size<loopCnt) loopCnt = size-20;
545 //if we already have a valid clock quit
546 for (; i < 8; ++i)
547 if (clk[i] == clock) return clock;
548
549 //get high and low peak
550 int peak, low;
551 if (getHiLo(dest, loopCnt, &peak, &low, 85, 85) < 1) return 0;
552
553 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
554 size_t ii;
555 uint8_t clkCnt;
556 uint8_t tol = 0;
557 uint16_t smplCnt = 0;
558 int16_t peakcnt = 0;
559 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
560 uint16_t minPeak = 255;
561 bool firstpeak = true;
562 //test for large clipped waves - ignore first peak
563 for (i=0; i<loopCnt; i++) {
564 if (dest[i] >= peak || dest[i] <= low) {
565 if (firstpeak) continue;
566 smplCnt++;
567 } else {
568 firstpeak = false;
569 if (smplCnt > 0) {
570 if (minPeak > smplCnt && smplCnt > 7) minPeak = smplCnt;
571 peakcnt++;
572 if (g_debugMode == 2) prnt("DEBUG NRZ: minPeak: %d, smplCnt: %d, peakcnt: %d",minPeak,smplCnt,peakcnt);
573 smplCnt = 0;
574 }
575 }
576 }
577 if (minPeak < 8) return 0;
578 bool errBitHigh = 0;
579 bool bitHigh = 0;
580 uint8_t ignoreCnt = 0;
581 uint8_t ignoreWindow = 4;
582 bool lastPeakHigh = 0;
583 int lastBit = 0;
584 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
585 peakcnt=0;
586 //test each valid clock from smallest to greatest to see which lines up
587 for(clkCnt=0; clkCnt < 8; ++clkCnt) {
588 //ignore clocks smaller than smallest peak
589 if (clk[clkCnt] < minPeak - (clk[clkCnt]/4)) continue;
590 //try lining up the peaks by moving starting point (try first 256)
591 for (ii=20; ii < loopCnt; ++ii) {
592 if ((dest[ii] >= peak) || (dest[ii] <= low)) {
593 peakcnt = 0;
594 bitHigh = false;
595 ignoreCnt = 0;
596 lastBit = ii-clk[clkCnt];
597 //loop through to see if this start location works
598 for (i = ii; i < size-20; ++i) {
599 //if we are at a clock bit
600 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
601 //test high/low
602 if (dest[i] >= peak || dest[i] <= low) {
603 //if same peak don't count it
604 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
605 peakcnt++;
606 }
607 lastPeakHigh = (dest[i] >= peak);
608 bitHigh = true;
609 errBitHigh = false;
610 ignoreCnt = ignoreWindow;
611 lastBit += clk[clkCnt];
612 } else if (i == lastBit + clk[clkCnt] + tol) {
613 lastBit += clk[clkCnt];
614 }
615 //else if not a clock bit and no peaks
616 } else if (dest[i] < peak && dest[i] > low) {
617 if (ignoreCnt==0) {
618 bitHigh=false;
619 if (errBitHigh==true) peakcnt--;
620 errBitHigh=false;
621 } else {
622 ignoreCnt--;
623 }
624 // else if not a clock bit but we have a peak
625 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
626 //error bar found no clock...
627 errBitHigh=true;
628 }
629 }
630 if(peakcnt>peaksdet[clkCnt]) {
631 bestStart[clkCnt]=ii;
632 peaksdet[clkCnt]=peakcnt;
633 }
634 }
635 }
636 }
637 int iii=7;
638 uint8_t best=0;
639 for (iii=7; iii > 0; iii--) {
640 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
641 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
642 best = iii;
643 }
644 } else if (peaksdet[iii] > peaksdet[best]) {
645 best = iii;
646 }
647 if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, minPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],minPeak, clk[best], lowestTransition);
648 }
649 *clockStartIdx = bestStart[best];
650 return clk[best];
651 }
652
653 //by marshmellow
654 //countFC is to detect the field clock lengths.
655 //counts and returns the 2 most common wave lengths
656 //mainly used for FSK field clock detection
657 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) {
658 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
659 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
660 uint8_t fcLensFnd = 0;
661 uint8_t lastFCcnt = 0;
662 uint8_t fcCounter = 0;
663 size_t i;
664 if (size < 180) return 0;
665
666 // prime i to first up transition
667 for (i = 160; i < size-20; i++)
668 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
669 break;
670
671 for (; i < size-20; i++){
672 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
673 // new up transition
674 fcCounter++;
675 if (fskAdj){
676 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
677 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
678 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
679 if ((fcCounter==9) || fcCounter==4) fcCounter++;
680 // save last field clock count (fc/xx)
681 lastFCcnt = fcCounter;
682 }
683 // find which fcLens to save it to:
684 for (int ii=0; ii<15; ii++){
685 if (fcLens[ii]==fcCounter){
686 fcCnts[ii]++;
687 fcCounter=0;
688 break;
689 }
690 }
691 if (fcCounter>0 && fcLensFnd<15){
692 //add new fc length
693 fcCnts[fcLensFnd]++;
694 fcLens[fcLensFnd++]=fcCounter;
695 }
696 fcCounter=0;
697 } else {
698 // count sample
699 fcCounter++;
700 }
701 }
702
703 uint8_t best1=14, best2=14, best3=14;
704 uint16_t maxCnt1=0;
705 // go through fclens and find which ones are bigest 2
706 for (i=0; i<15; i++){
707 // get the 3 best FC values
708 if (fcCnts[i]>maxCnt1) {
709 best3=best2;
710 best2=best1;
711 maxCnt1=fcCnts[i];
712 best1=i;
713 } else if(fcCnts[i]>fcCnts[best2]){
714 best3=best2;
715 best2=i;
716 } else if(fcCnts[i]>fcCnts[best3]){
717 best3=i;
718 }
719 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]);
720 if (fcLens[i]==0) break;
721 }
722 if (fcLens[best1]==0) return 0;
723 uint8_t fcH=0, fcL=0;
724 if (fcLens[best1]>fcLens[best2]){
725 fcH=fcLens[best1];
726 fcL=fcLens[best2];
727 } else{
728 fcH=fcLens[best2];
729 fcL=fcLens[best1];
730 }
731 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
732 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]);
733 return 0; //lots of waves not psk or fsk
734 }
735 // TODO: take top 3 answers and compare to known Field clocks to get top 2
736
737 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
738 if (fskAdj) return fcs;
739 return (uint16_t)fcLens[best2] << 8 | fcLens[best1];
740 }
741
742 //by marshmellow
743 //detect psk clock by reading each phase shift
744 // a phase shift is determined by measuring the sample length of each wave
745 int DetectPSKClock(uint8_t dest[], size_t size, int clock, size_t *firstPhaseShift, uint8_t *curPhase, uint8_t *fc) {
746 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
747 uint16_t loopCnt = 4096; //don't need to loop through entire array...
748 if (size == 0) return 0;
749 if (size+3<loopCnt) loopCnt = size-20;
750
751 uint16_t fcs = countFC(dest, size, 0);
752 *fc = fcs & 0xFF;
753 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d, FC2: %d",*fc, fcs>>8);
754 if ((fcs>>8) == 10 && *fc == 8) return -1;
755 if (*fc!=2 && *fc!=4 && *fc!=8) return -1;
756
757 //if we already have a valid clock quit
758 size_t i=1;
759 for (; i < 8; ++i)
760 if (clk[i] == clock) return clock;
761
762 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
763
764 uint8_t clkCnt, tol=1;
765 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0, fullWaveLen=0;
766 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
767 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
768
769 //find start of modulating data in trace
770 i = findModStart(dest, size, *fc);
771
772 firstFullWave = pskFindFirstPhaseShift(dest, size, curPhase, i, *fc, &fullWaveLen);
773 if (firstFullWave == 0) {
774 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
775 // so skip a little to ensure we are past any Start Signal
776 firstFullWave = 160;
777 fullWaveLen = 0;
778 }
779
780 *firstPhaseShift = firstFullWave;
781 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
782 //test each valid clock from greatest to smallest to see which lines up
783 for(clkCnt=7; clkCnt >= 1 ; clkCnt--) {
784 tol = *fc/2;
785 lastClkBit = firstFullWave; //set end of wave as clock align
786 waveStart = 0;
787 errCnt=0;
788 peakcnt=0;
789 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
790
791 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
792 //top edge of wave = start of new wave
793 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
794 if (waveStart == 0) {
795 waveStart = i+1;
796 waveLenCnt=0;
797 } else { //waveEnd
798 waveEnd = i+1;
799 waveLenCnt = waveEnd-waveStart;
800 if (waveLenCnt > *fc){
801 //if this wave is a phase shift
802 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);
803 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
804 peakcnt++;
805 lastClkBit+=clk[clkCnt];
806 } else if (i<lastClkBit+8){
807 //noise after a phase shift - ignore
808 } else { //phase shift before supposed to based on clock
809 errCnt++;
810 }
811 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + *fc){
812 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
813 }
814 waveStart=i+1;
815 }
816 }
817 }
818 if (errCnt == 0){
819 return clk[clkCnt];
820 }
821 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
822 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
823 }
824 //all tested with errors
825 //return the highest clk with the most peaks found
826 uint8_t best=7;
827 for (i=7; i>=1; i--){
828 if (peaksdet[i] > peaksdet[best]) {
829 best = i;
830 }
831 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
832 }
833 return clk[best];
834 }
835
836 //int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
837 // size_t firstPhaseShift = 0;
838 // uint8_t curPhase = 0;
839 // return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift, &curPhase);
840 //}
841
842 //by marshmellow
843 //detects the bit clock for FSK given the high and low Field Clocks
844 uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
845 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
846 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
847 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
848 uint8_t rfLensFnd = 0;
849 uint8_t lastFCcnt = 0;
850 uint16_t fcCounter = 0;
851 uint16_t rfCounter = 0;
852 uint8_t firstBitFnd = 0;
853 size_t i;
854 if (size == 0) return 0;
855
856 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
857 rfLensFnd=0;
858 fcCounter=0;
859 rfCounter=0;
860 firstBitFnd=0;
861 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
862 // prime i to first peak / up transition
863 for (i = 160; i < size-20; i++)
864 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
865 break;
866
867 for (; i < size-20; i++){
868 fcCounter++;
869 rfCounter++;
870
871 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
872 continue;
873 // else new peak
874 // if we got less than the small fc + tolerance then set it to the small fc
875 // if it is inbetween set it to the last counter
876 if (fcCounter < fcHigh && fcCounter > fcLow)
877 fcCounter = lastFCcnt;
878 else if (fcCounter < fcLow+fcTol)
879 fcCounter = fcLow;
880 else //set it to the large fc
881 fcCounter = fcHigh;
882
883 //look for bit clock (rf/xx)
884 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
885 //not the same size as the last wave - start of new bit sequence
886 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
887 for (int ii=0; ii<15; ii++){
888 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
889 rfCnts[ii]++;
890 rfCounter = 0;
891 break;
892 }
893 }
894 if (rfCounter > 0 && rfLensFnd < 15){
895 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
896 rfCnts[rfLensFnd]++;
897 rfLens[rfLensFnd++] = rfCounter;
898 }
899 } else {
900 *firstClockEdge = i;
901 firstBitFnd++;
902 }
903 rfCounter=0;
904 lastFCcnt=fcCounter;
905 }
906 fcCounter=0;
907 }
908 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
909
910 for (i=0; i<15; i++){
911 //get highest 2 RF values (might need to get more values to compare or compare all?)
912 if (rfCnts[i]>rfCnts[rfHighest]){
913 rfHighest3=rfHighest2;
914 rfHighest2=rfHighest;
915 rfHighest=i;
916 } else if(rfCnts[i]>rfCnts[rfHighest2]){
917 rfHighest3=rfHighest2;
918 rfHighest2=i;
919 } else if(rfCnts[i]>rfCnts[rfHighest3]){
920 rfHighest3=i;
921 }
922 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
923 }
924 // set allowed clock remainder tolerance to be 1 large field clock length+1
925 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
926 uint8_t tol1 = fcHigh+1;
927
928 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
929
930 // loop to find the highest clock that has a remainder less than the tolerance
931 // compare samples counted divided by
932 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
933 int ii=7;
934 for (; ii>=2; ii--){
935 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
936 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
937 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
938 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
939 break;
940 }
941 }
942 }
943 }
944
945 if (ii<2) return 0; // oops we went too far
946
947 return clk[ii];
948 }
949
950 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
951 int firstClockEdge = 0;
952 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
953 }
954
955 //**********************************************************************************************
956 //--------------------Modulation Demods &/or Decoding Section-----------------------------------
957 //**********************************************************************************************
958
959 // look for Sequence Terminator - should be pulses of clk*(1 or 2), clk*2, clk*(1.5 or 2), by idx we mean graph position index...
960 bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, size_t *i) {
961 for (; *i < buffSize - 4; *i+=1) {
962 *stStartIdx += lowToLowWaveLen[*i]; //caution part of this wave may be data and part may be ST.... to be accounted for in main function for now...
963 if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
964 if (lowToLowWaveLen[*i+1] >= clk*2-tol && lowToLowWaveLen[*i+1] <= clk*2+tol && highToLowWaveLen[*i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2
965 if (lowToLowWaveLen[*i+2] >= (clk*3)/2-tol && lowToLowWaveLen[*i+2] <= clk*2+tol && highToLowWaveLen[*i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave
966 if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
967 *stStopLoc = *i + 3;
968 return true;
969 }
970 }
971 }
972 }
973 }
974 return false;
975 }
976 //by marshmellow
977 //attempt to identify a Sequence Terminator in ASK modulated raw wave
978 bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
979 size_t bufsize = *size;
980 //need to loop through all samples and identify our clock, look for the ST pattern
981 int clk = 0;
982 int tol = 0;
983 int j=0, high, low, skip=0, start=0, end=0, minClk=255;
984 size_t i = 0;
985 //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
986 int tmpbuff[bufsize / LOWEST_DEFAULT_CLOCK]; // low to low wave count //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
987 int waveLen[bufsize / LOWEST_DEFAULT_CLOCK]; // high to low wave count //if clock is larger then we waste memory in array size that is not needed...
988 //size_t testsize = (bufsize < 512) ? bufsize : 512;
989 int phaseoff = 0;
990 high = low = 128;
991 memset(tmpbuff, 0, sizeof(tmpbuff));
992 memset(waveLen, 0, sizeof(waveLen));
993
994 if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
995 // set clock - might be able to get this externally and remove this work...
996 clk = getClosestClock(minClk);
997 // clock not found - ERROR
998 if (clk == 0) {
999 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1000 return false;
1001 }
1002 *foundclock = clk;
1003
1004 tol = clk/8;
1005 if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
1006 // first ST not found - ERROR
1007 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1008 return false;
1009 } else {
1010 if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
1011 }
1012 if (waveLen[i+2] > clk*1+tol)
1013 phaseoff = 0;
1014 else
1015 phaseoff = clk/2;
1016
1017 // skip over the remainder of ST
1018 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1019
1020 // now do it again to find the end
1021 int dummy1 = 0;
1022 end = skip;
1023 i+=3;
1024 if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
1025 //didn't find second ST - ERROR
1026 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1027 return false;
1028 }
1029 end -= phaseoff;
1030 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);
1031 //now begin to trim out ST so we can use normal demod cmds
1032 start = skip;
1033 size_t datalen = end - start;
1034 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1035 if ( clk - (datalen % clk) <= clk/8) {
1036 // padd the amount off - could be problematic... but shouldn't happen often
1037 datalen += clk - (datalen % clk);
1038 } else if ( (datalen % clk) <= clk/8 ) {
1039 // padd the amount off - could be problematic... but shouldn't happen often
1040 datalen -= datalen % clk;
1041 } else {
1042 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1043 return false;
1044 }
1045 // if datalen is less than one t55xx block - ERROR
1046 if (datalen/clk < 8*4) {
1047 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1048 return false;
1049 }
1050 size_t dataloc = start;
1051 if (buffer[dataloc-(clk*4)-(clk/4)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1052 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1053 for ( i=0; i <= (clk/4); ++i ) {
1054 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1055 dataloc -= i;
1056 break;
1057 }
1058 }
1059 }
1060
1061 size_t newloc = 0;
1062 i=0;
1063 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1064 bool firstrun = true;
1065 // warning - overwriting buffer given with raw wave data with ST removed...
1066 while ( dataloc < bufsize-(clk/2) ) {
1067 //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)
1068 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+clk/4]<high && buffer[dataloc+clk/4]>low) {
1069 for(i=0; i < clk/2-tol; ++i) {
1070 buffer[dataloc+i] = high+5;
1071 }
1072 } //test for small spike outlier (high between two lows) in the case of very strong waves
1073 if (buffer[dataloc] > low && buffer[dataloc+clk/4] <= low) {
1074 for(i=0; i < clk/4; ++i) {
1075 buffer[dataloc+i] = buffer[dataloc+clk/4];
1076 }
1077 }
1078 if (firstrun) {
1079 *stend = dataloc;
1080 *ststart = dataloc-(clk*4);
1081 firstrun=false;
1082 }
1083 for (i=0; i<datalen; ++i) {
1084 if (i+newloc < bufsize) {
1085 if (i+newloc < dataloc)
1086 buffer[i+newloc] = buffer[dataloc];
1087
1088 dataloc++;
1089 }
1090 }
1091 newloc += i;
1092 //skip next ST - we just assume it will be there from now on...
1093 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1094 dataloc += clk*4;
1095 }
1096 *size = newloc;
1097 return true;
1098 }
1099 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1100 size_t ststart = 0, stend = 0;
1101 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1102 }
1103
1104 //by marshmellow
1105 //take 11 10 01 11 00 and make 01100 ... miller decoding
1106 //check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
1107 //decodes miller encoded binary
1108 //NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
1109 int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
1110 if (*size < 16) return -1;
1111 uint16_t MaxBits = 512, errCnt = 0;
1112 size_t i, bitCnt=0;
1113 uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
1114 uint8_t halfClkErr = 0;
1115 //find alignment, needs 4 1s or 0s to properly align
1116 for (i=1; i < *size-1; i++) {
1117 alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
1118 curBit = BitStream[i];
1119 if (alignCnt == 4) break;
1120 }
1121 // for now error if alignment not found. later add option to run it with multiple offsets...
1122 if (alignCnt != 4) {
1123 if (g_debugMode) prnt("ERROR MillerDecode: alignment not found so either your bitstream is not miller or your data does not have a 101 in it");
1124 return -1;
1125 }
1126 alignedIdx = (i-1) % 2;
1127 for (i=alignedIdx; i < *size-3; i+=2) {
1128 halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
1129 if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
1130 errCnt++;
1131 BitStream[bitCnt++] = 7;
1132 continue;
1133 }
1134 BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
1135
1136 if (bitCnt > MaxBits) break;
1137 }
1138 *size = bitCnt;
1139 return errCnt;
1140 }
1141
1142 //by marshmellow
1143 //take 01 or 10 = 1 and 11 or 00 = 0
1144 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
1145 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1146 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) {
1147 uint16_t bitnum = 0;
1148 uint16_t errCnt = 0;
1149 size_t i = offset;
1150 uint16_t MaxBits=512;
1151 //if not enough samples - error
1152 if (*size < 51) return -1;
1153 //check for phase change faults - skip one sample if faulty
1154 uint8_t offsetA = 1, offsetB = 1;
1155 for (; i<48; i+=2){
1156 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
1157 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
1158 }
1159 if (!offsetA && offsetB) offset++;
1160 for (i=offset; i<*size-3; i+=2){
1161 //check for phase error
1162 if (BitStream[i+1]==BitStream[i+2]) {
1163 BitStream[bitnum++]=7;
1164 errCnt++;
1165 }
1166 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1167 BitStream[bitnum++]=1^invert;
1168 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1169 BitStream[bitnum++]=invert;
1170 } else {
1171 BitStream[bitnum++]=7;
1172 errCnt++;
1173 }
1174 if(bitnum>MaxBits) break;
1175 }
1176 *size=bitnum;
1177 return errCnt;
1178 }
1179
1180 //by marshmellow
1181 //take 10 and 01 and manchester decode
1182 //run through 2 times and take least errCnt
1183 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) {
1184 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
1185 size_t i, ii;
1186 uint16_t bestErr = 1000, bestRun = 0;
1187 if (*size < 16) return -1;
1188 //find correct start position [alignment]
1189 for (ii=0;ii<2;++ii){
1190 for (i=ii; i<*size-3; i+=2)
1191 if (BitStream[i]==BitStream[i+1])
1192 errCnt++;
1193
1194 if (bestErr>errCnt){
1195 bestErr=errCnt;
1196 bestRun=ii;
1197 }
1198 errCnt=0;
1199 }
1200 *alignPos=bestRun;
1201 //decode
1202 for (i=bestRun; i < *size-3; i+=2){
1203 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
1204 BitStream[bitnum++]=invert;
1205 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
1206 BitStream[bitnum++]=invert^1;
1207 } else {
1208 BitStream[bitnum++]=7;
1209 }
1210 if(bitnum>MaxBits) break;
1211 }
1212 *size=bitnum;
1213 return bestErr;
1214 }
1215
1216 //by marshmellow
1217 //demodulates strong heavily clipped samples
1218 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
1219 {
1220 *startIdx=0;
1221 size_t bitCnt=0, smplCnt=1, errCnt=0;
1222 bool waveHigh = (BinStream[0] >= high);
1223 for (size_t i=1; i < *size; i++){
1224 if (BinStream[i] >= high && waveHigh){
1225 smplCnt++;
1226 } else if (BinStream[i] <= low && !waveHigh){
1227 smplCnt++;
1228 } else { //transition
1229 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
1230 if (smplCnt > clk-(clk/4)-1) { //full clock
1231 if (smplCnt > clk + (clk/4)+1) { //too many samples
1232 errCnt++;
1233 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1234 BinStream[bitCnt++] = 7;
1235 } else if (waveHigh) {
1236 BinStream[bitCnt++] = invert;
1237 BinStream[bitCnt++] = invert;
1238 } else if (!waveHigh) {
1239 BinStream[bitCnt++] = invert ^ 1;
1240 BinStream[bitCnt++] = invert ^ 1;
1241 }
1242 if (*startIdx==0) *startIdx = i-clk;
1243 waveHigh = !waveHigh;
1244 smplCnt = 0;
1245 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
1246 if (waveHigh) {
1247 BinStream[bitCnt++] = invert;
1248 } else if (!waveHigh) {
1249 BinStream[bitCnt++] = invert ^ 1;
1250 }
1251 if (*startIdx==0) *startIdx = i-(clk/2);
1252 waveHigh = !waveHigh;
1253 smplCnt = 0;
1254 } else {
1255 smplCnt++;
1256 //transition bit oops
1257 }
1258 } else { //haven't hit new high or new low yet
1259 smplCnt++;
1260 }
1261 }
1262 }
1263 *size = bitCnt;
1264 return errCnt;
1265 }
1266
1267 //by marshmellow
1268 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
1269 int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
1270 if (*size==0) return -1;
1271 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
1272 if (*clk==0 || start < 0) return -3;
1273 if (*invert != 1) *invert = 0;
1274 if (amp==1) askAmp(BinStream, *size);
1275 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
1276
1277 //start pos from detect ask clock is 1/2 clock offset
1278 // NOTE: can be negative (demod assumes rest of wave was there)
1279 *startIdx = start - (*clk/2);
1280 uint8_t initLoopMax = 255;
1281 if (initLoopMax > *size) initLoopMax = *size;
1282 // Detect high and lows
1283 //25% clip in case highs and lows aren't clipped [marshmellow]
1284 int high, low;
1285 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
1286 return -2; //just noise
1287
1288 size_t errCnt = 0;
1289 // if clean clipped waves detected run alternate demod
1290 if (DetectCleanAskWave(BinStream, *size, high, low)) {
1291 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
1292 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
1293 if (askType) { //askman
1294 uint8_t alignPos = 0;
1295 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
1296 *startIdx += *clk/2 * alignPos;
1297 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
1298 return errCnt;
1299 } else { //askraw
1300 return errCnt;
1301 }
1302 }
1303 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
1304 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
1305
1306 int lastBit; //set first clock check - can go negative
1307 size_t i, bitnum = 0; //output counter
1308 uint8_t midBit = 0;
1309 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
1310 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
1311 size_t MaxBits = 3072; //max bits to collect
1312 lastBit = start - *clk;
1313
1314 for (i = start; i < *size; ++i) {
1315 if (i-lastBit >= *clk-tol){
1316 if (BinStream[i] >= high) {
1317 BinStream[bitnum++] = *invert;
1318 } else if (BinStream[i] <= low) {
1319 BinStream[bitnum++] = *invert ^ 1;
1320 } else if (i-lastBit >= *clk+tol) {
1321 if (bitnum > 0) {
1322 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1323 BinStream[bitnum++]=7;
1324 errCnt++;
1325 }
1326 } else { //in tolerance - looking for peak
1327 continue;
1328 }
1329 midBit = 0;
1330 lastBit += *clk;
1331 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
1332 if (BinStream[i] >= high) {
1333 BinStream[bitnum++] = *invert;
1334 } else if (BinStream[i] <= low) {
1335 BinStream[bitnum++] = *invert ^ 1;
1336 } else if (i-lastBit >= *clk/2+tol) {
1337 BinStream[bitnum] = BinStream[bitnum-1];
1338 bitnum++;
1339 } else { //in tolerance - looking for peak
1340 continue;
1341 }
1342 midBit = 1;
1343 }
1344 if (bitnum >= MaxBits) break;
1345 }
1346 *size = bitnum;
1347 return errCnt;
1348 }
1349
1350 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
1351 int start = 0;
1352 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
1353 }
1354
1355 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1356 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1357 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1358 if (justNoise(dest, *size)) return -1;
1359 size_t clkStartIdx = 0;
1360 *clk = DetectNRZClock(dest, *size, *clk, &clkStartIdx);
1361 if (*clk==0) return -2;
1362 size_t i, gLen = 4096;
1363 if (gLen>*size) gLen = *size-20;
1364 int high, low;
1365 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1366
1367 uint8_t bit=0;
1368 //convert wave samples to 1's and 0's
1369 for(i=20; i < *size-20; i++){
1370 if (dest[i] >= high) bit = 1;
1371 if (dest[i] <= low) bit = 0;
1372 dest[i] = bit;
1373 }
1374 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1375 size_t lastBit = 0;
1376 size_t numBits = 0;
1377 for(i=21; i < *size-20; i++) {
1378 //if transition detected or large number of same bits - store the passed bits
1379 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1380 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1381 numBits += (i - lastBit + (*clk/4)) / *clk;
1382 if (lastBit == 0) {
1383 *startIdx = i - (numBits * *clk);
1384 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1385 }
1386 lastBit = i-1;
1387 }
1388 }
1389 *size = numBits;
1390 return 0;
1391 }
1392
1393 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
1394 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1395 size_t last_transition = 0;
1396 size_t idx = 1;
1397 if (fchigh==0) fchigh=10;
1398 if (fclow==0) fclow=8;
1399 //set the threshold close to 0 (graph) or 128 std to avoid static
1400 size_t preLastSample = 0;
1401 size_t LastSample = 0;
1402 size_t currSample = 0;
1403 if ( size < 1024 ) return 0; // not enough samples
1404
1405 //find start of modulating data in trace
1406 idx = findModStart(dest, size, fchigh);
1407 // Need to threshold first sample
1408 if(dest[idx] < FSK_PSK_THRESHOLD) dest[0] = 0;
1409 else dest[0] = 1;
1410
1411 last_transition = idx;
1412 idx++;
1413 size_t numBits = 0;
1414 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
1415 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
1416 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
1417 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
1418 for(; idx < size; idx++) {
1419 // threshold current value
1420 if (dest[idx] < FSK_PSK_THRESHOLD) dest[idx] = 0;
1421 else dest[idx] = 1;
1422
1423 // Check for 0->1 transition
1424 if (dest[idx-1] < dest[idx]) {
1425 preLastSample = LastSample;
1426 LastSample = currSample;
1427 currSample = idx-last_transition;
1428 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
1429 //do nothing with extra garbage
1430 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
1431 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
1432 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
1433 dest[numBits-1]=1;
1434 }
1435 dest[numBits++]=1;
1436 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1437 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
1438 //do nothing with beginning garbage and reset.. should be rare..
1439 numBits = 0;
1440 } 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)
1441 dest[numBits++]=1;
1442 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1443 } else { //9+ = 10 sample waves (or 6+ = 7)
1444 dest[numBits++]=0;
1445 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
1446 }
1447 last_transition = idx;
1448 }
1449 }
1450 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
1451 }
1452
1453 //translate 11111100000 to 10
1454 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
1455 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1456 uint8_t lastval=dest[0];
1457 size_t idx=0;
1458 size_t numBits=0;
1459 uint32_t n=1;
1460 for( idx=1; idx < size; idx++) {
1461 n++;
1462 if (dest[idx]==lastval) continue; //skip until we hit a transition
1463
1464 //find out how many bits (n) we collected (use 1/2 clk tolerance)
1465 //if lastval was 1, we have a 1->0 crossing
1466 if (dest[idx-1]==1) {
1467 n = (n * fclow + rfLen/2) / rfLen;
1468 } else {// 0->1 crossing
1469 n = (n * fchigh + rfLen/2) / rfLen;
1470 }
1471 if (n == 0) n = 1;
1472
1473 //first transition - save startidx
1474 if (numBits == 0) {
1475 if (lastval == 1) { //high to low
1476 *startIdx += (fclow * idx) - (n*rfLen);
1477 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
1478 } else {
1479 *startIdx += (fchigh * idx) - (n*rfLen);
1480 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
1481 }
1482 }
1483
1484 //add to our destination the bits we collected
1485 memset(dest+numBits, dest[idx-1]^invert , n);
1486 numBits += n;
1487 n=0;
1488 lastval=dest[idx];
1489 }//end for
1490 // if valid extra bits at the end were all the same frequency - add them in
1491 if (n > rfLen/fchigh) {
1492 if (dest[idx-2]==1) {
1493 n = (n * fclow + rfLen/2) / rfLen;
1494 } else {
1495 n = (n * fchigh + rfLen/2) / rfLen;
1496 }
1497 memset(dest+numBits, dest[idx-1]^invert , n);
1498 numBits += n;
1499 }
1500 return numBits;
1501 }
1502
1503 //by marshmellow (from holiman's base)
1504 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
1505 int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1506 // FSK demodulator
1507 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
1508 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
1509 return size;
1510 }
1511
1512 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
1513 int startIdx=0;
1514 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
1515 }
1516
1517 // by marshmellow
1518 // convert psk1 demod to psk2 demod
1519 // only transition waves are 1s
1520 void psk1TOpsk2(uint8_t *BitStream, size_t size) {
1521 size_t i=1;
1522 uint8_t lastBit=BitStream[0];
1523 for (; i<size; i++){
1524 if (BitStream[i]==7){
1525 //ignore errors
1526 } else if (lastBit!=BitStream[i]){
1527 lastBit=BitStream[i];
1528 BitStream[i]=1;
1529 } else {
1530 BitStream[i]=0;
1531 }
1532 }
1533 return;
1534 }
1535
1536 // by marshmellow
1537 // convert psk2 demod to psk1 demod
1538 // from only transition waves are 1s to phase shifts change bit
1539 void psk2TOpsk1(uint8_t *BitStream, size_t size) {
1540 uint8_t phase=0;
1541 for (size_t i=0; i<size; i++){
1542 if (BitStream[i]==1){
1543 phase ^=1;
1544 }
1545 BitStream[i]=phase;
1546 }
1547 return;
1548 }
1549
1550 //by marshmellow - demodulate PSK1 wave
1551 //uses wave lengths (# Samples)
1552 int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1553 if (*size < 170) return -1;
1554
1555 uint8_t curPhase = *invert;
1556 uint8_t fc=0;
1557 size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1558 uint16_t fullWaveLen=0, waveLenCnt=0, avgWaveVal;
1559 uint16_t errCnt=0, errCnt2=0;
1560
1561 *clock = DetectPSKClock(dest, *size, *clock, &firstFullWave, &curPhase, &fc);
1562 if (*clock == 0) return -1;
1563 //if clock detect found firstfullwave...
1564 uint16_t tol = fc/2;
1565 if (firstFullWave == 0) {
1566 //find start of modulating data in trace
1567 i = findModStart(dest, *size, fc);
1568 //find first phase shift
1569 firstFullWave = pskFindFirstPhaseShift(dest, *size, &curPhase, i, fc, &fullWaveLen);
1570 if (firstFullWave == 0) {
1571 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1572 // so skip a little to ensure we are past any Start Signal
1573 firstFullWave = 160;
1574 memset(dest, curPhase, firstFullWave / *clock);
1575 } else {
1576 memset(dest, curPhase^1, firstFullWave / *clock);
1577 }
1578 } else {
1579 memset(dest, curPhase^1, firstFullWave / *clock);
1580 }
1581 //advance bits
1582 numBits += (firstFullWave / *clock);
1583 *startIdx = firstFullWave - (*clock * numBits)+2;
1584 //set start of wave as clock align
1585 lastClkBit = firstFullWave;
1586 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1587 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1588 waveStart = 0;
1589 dest[numBits++] = curPhase; //set first read bit
1590 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++) {
1591 //top edge of wave = start of new wave
1592 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]) {
1593 if (waveStart == 0) {
1594 waveStart = i+1;
1595 waveLenCnt = 0;
1596 avgWaveVal = dest[i+1];
1597 } else { //waveEnd
1598 waveEnd = i+1;
1599 waveLenCnt = waveEnd-waveStart;
1600 if (waveLenCnt > fc) {
1601 //this wave is a phase shift
1602 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1603 if (i+1 >= lastClkBit + *clock - tol) { //should be a clock bit
1604 curPhase ^= 1;
1605 dest[numBits++] = curPhase;
1606 lastClkBit += *clock;
1607 } else if (i < lastClkBit+10+fc) {
1608 //noise after a phase shift - ignore
1609 } else { //phase shift before supposed to based on clock
1610 errCnt++;
1611 dest[numBits++] = 7;
1612 }
1613 } else if (i+1 > lastClkBit + *clock + tol + fc) {
1614 lastClkBit += *clock; //no phase shift but clock bit
1615 dest[numBits++] = curPhase;
1616 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1617 errCnt2++;
1618 if(errCnt2 > 101) return errCnt2;
1619 avgWaveVal += dest[i+1];
1620 continue;
1621 }
1622 avgWaveVal = 0;
1623 waveStart = i+1;
1624 }
1625 }
1626 avgWaveVal += dest[i+1];
1627 }
1628 *size = numBits;
1629 return errCnt;
1630 }
1631
1632 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1633 int startIdx = 0;
1634 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
1635 }
1636
1637 //**********************************************************************************************
1638 //-----------------Tag format detection section-------------------------------------------------
1639 //**********************************************************************************************
1640
1641 // by marshmellow
1642 // FSK Demod then try to locate an AWID ID
1643 int AWIDdemodFSK(uint8_t *dest, size_t *size) {
1644 //make sure buffer has enough data
1645 if (*size < 96*50) return -1;
1646
1647 if (justNoise(dest, *size)) return -2;
1648
1649 // FSK demodulator
1650 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1651 if (*size < 96) return -3; //did we get a good demod?
1652
1653 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
1654 size_t startIdx = 0;
1655 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1656 if (errChk == 0) return -4; //preamble not found
1657 if (*size != 96) return -5;
1658 return (int)startIdx;
1659 }
1660
1661 //by marshmellow
1662 //takes 1s and 0s and searches for EM410x format - output EM ID
1663 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
1664 {
1665 //sanity checks
1666 if (*size < 64) return 0;
1667 if (BitStream[1]>1) return 0; //allow only 1s and 0s
1668
1669 // 111111111 bit pattern represent start of frame
1670 // include 0 in front to help get start pos
1671 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
1672 uint8_t errChk = 0;
1673 uint8_t FmtLen = 10; // sets of 4 bits = end data
1674 *startIdx = 0;
1675 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
1676 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
1677 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
1678
1679 //skip last 4bit parity row for simplicity
1680 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
1681 if (*size == 40) { // std em410x format
1682 *hi = 0;
1683 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
1684 } else if (*size == 88) { // long em format
1685 *hi = (bytebits_to_byte(BitStream, 24));
1686 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
1687 } else {
1688 if (g_debugMode) prnt("Error removing parity: %u", *size);
1689 return 0;
1690 }
1691 return 1;
1692 }
1693
1694 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
1695 // BitStream must contain previously askrawdemod and biphasedemoded data
1696 int FDXBdemodBI(uint8_t *dest, size_t *size) {
1697 //make sure buffer has enough data
1698 if (*size < 128) return -1;
1699
1700 size_t startIdx = 0;
1701 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
1702
1703 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1704 if (errChk == 0) return -2; //preamble not found
1705 if (*size != 128) return -3; //wrong size for fdxb
1706 //return start position
1707 return (int)startIdx;
1708 }
1709
1710 // by marshmellow
1711 // demod gProxIIDemod
1712 // error returns as -x
1713 // success returns start position in BitStream
1714 // BitStream must contain previously askrawdemod and biphasedemoded data
1715 int gProxII_Demod(uint8_t BitStream[], size_t *size) {
1716 size_t startIdx=0;
1717 uint8_t preamble[] = {1,1,1,1,1,0};
1718
1719 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
1720 if (errChk == 0) return -3; //preamble not found
1721 if (*size != 96) return -2; //should have found 96 bits
1722 //check first 6 spacer bits to verify format
1723 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
1724 //confirmed proper separator bits found
1725 //return start position
1726 return (int) startIdx;
1727 }
1728 return -5; //spacer bits not found - not a valid gproxII
1729 }
1730
1731 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
1732 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1733 if (justNoise(dest, *size)) return -1;
1734
1735 size_t numStart=0, size2=*size, startIdx=0;
1736 // FSK demodulator
1737 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1738 if (*size < 96*2) return -2;
1739 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1740 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
1741 // find bitstring in array
1742 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1743 if (errChk == 0) return -3; //preamble not found
1744
1745 numStart = startIdx + sizeof(preamble);
1746 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1747 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1748 if (dest[idx] == dest[idx+1]){
1749 return -4; //not manchester data
1750 }
1751 *hi2 = (*hi2<<1)|(*hi>>31);
1752 *hi = (*hi<<1)|(*lo>>31);
1753 //Then, shift in a 0 or one into low
1754 if (dest[idx] && !dest[idx+1]) // 1 0
1755 *lo=(*lo<<1)|1;
1756 else // 0 1
1757 *lo=(*lo<<1)|0;
1758 }
1759 return (int)startIdx;
1760 }
1761
1762 int IOdemodFSK(uint8_t *dest, size_t size) {
1763 if (justNoise(dest, size)) return -1;
1764 //make sure buffer has data
1765 if (size < 66*64) return -2;
1766 // FSK demodulator
1767 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
1768 if (size < 65) return -3; //did we get a good demod?
1769 //Index map
1770 //0 10 20 30 40 50 60
1771 //| | | | | | |
1772 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
1773 //-----------------------------------------------------------------------------
1774 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
1775 //
1776 //XSF(version)facility:codeone+codetwo
1777 //Handle the data
1778 size_t startIdx = 0;
1779 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
1780 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
1781 if (errChk == 0) return -4; //preamble not found
1782
1783 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
1784 //confirmed proper separator bits found
1785 //return start position
1786 return (int) startIdx;
1787 }
1788 return -5;
1789 }
1790
1791 // redesigned by marshmellow adjusted from existing decode functions
1792 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1793 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1794 //26 bit 40134 format (don't know other formats)
1795 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};
1796 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};
1797 size_t startidx = 0;
1798 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1799 // if didn't find preamble try again inverting
1800 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1801 *invert ^= 1;
1802 }
1803 if (*size != 64 && *size != 224) return -2;
1804 if (*invert==1)
1805 for (size_t i = startidx; i < *size + startidx; i++)
1806 bitStream[i] ^= 1;
1807
1808 return (int) startidx;
1809 }
1810
1811 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
1812 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1813 if (justNoise(dest, *size)) return -1;
1814
1815 size_t numStart=0, size2=*size, startIdx=0;
1816 // FSK demodulator
1817 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1818 if (*size < 96) return -2;
1819
1820 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1821 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
1822
1823 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1824 if (errChk == 0) return -3; //preamble not found
1825
1826 numStart = startIdx + sizeof(preamble);
1827 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1828 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1829 if (dest[idx] == dest[idx+1])
1830 return -4; //not manchester data
1831 *hi2 = (*hi2<<1)|(*hi>>31);
1832 *hi = (*hi<<1)|(*lo>>31);
1833 //Then, shift in a 0 or one into low
1834 if (dest[idx] && !dest[idx+1]) // 1 0
1835 *lo=(*lo<<1)|1;
1836 else // 0 1
1837 *lo=(*lo<<1)|0;
1838 }
1839 return (int)startIdx;
1840 }
1841
1842 // find presco preamble 0x10D in already demoded data
1843 int PrescoDemod(uint8_t *dest, size_t *size) {
1844 //make sure buffer has data
1845 if (*size < 64*2) return -2;
1846
1847 size_t startIdx = 0;
1848 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
1849 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1850 if (errChk == 0) return -4; //preamble not found
1851 //return start position
1852 return (int) startIdx;
1853 }
1854
1855 // by marshmellow
1856 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
1857 int PyramiddemodFSK(uint8_t *dest, size_t *size) {
1858 //make sure buffer has data
1859 if (*size < 128*50) return -5;
1860
1861 //test samples are not just noise
1862 if (justNoise(dest, *size)) return -1;
1863
1864 // FSK demodulator
1865 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1866 if (*size < 128) return -2; //did we get a good demod?
1867
1868 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
1869 size_t startIdx = 0;
1870 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1871 if (errChk == 0) return -4; //preamble not found
1872 if (*size != 128) return -3;
1873 return (int)startIdx;
1874 }
1875
1876 // by marshmellow
1877 // find viking preamble 0xF200 in already demoded data
1878 int VikingDemod_AM(uint8_t *dest, size_t *size) {
1879 //make sure buffer has data
1880 if (*size < 64*2) return -2;
1881
1882 size_t startIdx = 0;
1883 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};
1884 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1885 if (errChk == 0) return -4; //preamble not found
1886 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
1887 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
1888 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
1889 if ( checkCalc != 0xA8 ) return -5;
1890 if (*size != 64) return -6;
1891 //return start position
1892 return (int) startIdx;
1893 }
1894
1895 // by iceman
1896 // find Visa2000 preamble in already demoded data
1897 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1898 if (*size < 96) return -1; //make sure buffer has data
1899 size_t startIdx = 0;
1900 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};
1901 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1902 return -2; //preamble not found
1903 if (*size != 96) return -3; //wrong demoded size
1904 //return start position
1905 return (int)startIdx;
1906 }
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