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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 - 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 <stdint.h> // for uint_32+
37 #include <stdbool.h> // for bool
38
39 //**********************************************************************************************
40 //---------------------------------Utilities Section--------------------------------------------
41 //**********************************************************************************************
42 #define LOWEST_DEFAULT_CLOCK 32
43 #define FSK_PSK_THRESHOLD 123
44
45 //to allow debug print calls when used not on device
46 void dummy(char *fmt, ...){}
47 #ifndef ON_DEVICE
48 #include "ui.h"
49 #include "cmdparser.h"
50 #include "cmddata.h"
51 #define prnt PrintAndLog
52 #else
53 uint8_t g_debugMode=0;
54 #define prnt dummy
55 #endif
56
57 uint8_t justNoise(uint8_t *BitStream, size_t size) {
58 //test samples are not just noise
59 uint8_t justNoise1 = 1;
60 for(size_t idx=0; idx < size && justNoise1 ;idx++){
61 justNoise1 = BitStream[idx] < FSK_PSK_THRESHOLD;
62 }
63 return justNoise1;
64 }
65
66 //by marshmellow
67 //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
68 int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) {
69 *high=0;
70 *low=255;
71 // get high and low thresholds
72 for (size_t i=0; i < size; i++){
73 if (BitStream[i] > *high) *high = BitStream[i];
74 if (BitStream[i] < *low) *low = BitStream[i];
75 }
76 if (*high < FSK_PSK_THRESHOLD) return -1; // just noise
77 *high = ((*high-128)*fuzzHi + 12800)/100;
78 *low = ((*low-128)*fuzzLo + 12800)/100;
79 return 1;
80 }
81
82 // by marshmellow
83 // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
84 // returns 1 if passed
85 uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) {
86 uint8_t ans = 0;
87 for (uint8_t i = 0; i < bitLen; i++){
88 ans ^= ((bits >> i) & 1);
89 }
90 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
91 return (ans == pType);
92 }
93
94 // by marshmellow
95 // takes a array of binary values, start position, length of bits per parity (includes parity bit),
96 // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
97 size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) {
98 uint32_t parityWd = 0;
99 size_t j = 0, bitCnt = 0;
100 for (int word = 0; word < (bLen); word+=pLen) {
101 for (int bit=0; bit < pLen; bit++) {
102 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
103 BitStream[j++] = (BitStream[startIdx+word+bit]);
104 }
105 if (word+pLen > bLen) break;
106
107 j--; // overwrite parity with next data
108 // if parity fails then return 0
109 switch (pType) {
110 case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
111 case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
112 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
113 }
114 bitCnt+=(pLen-1);
115 parityWd = 0;
116 }
117 // if we got here then all the parities passed
118 //return ID start index and size
119 return bitCnt;
120 }
121
122 // by marshmellow
123 // takes a array of binary values, length of bits per parity (includes parity bit),
124 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
125 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
126 size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) {
127 uint32_t parityWd = 0;
128 size_t j = 0, bitCnt = 0;
129 for (int word = 0; word < sourceLen; word+=pLen-1) {
130 for (int bit=0; bit < pLen-1; bit++){
131 parityWd = (parityWd << 1) | BitSource[word+bit];
132 dest[j++] = (BitSource[word+bit]);
133 }
134 // if parity fails then return 0
135 switch (pType) {
136 case 3: dest[j++]=0; break; // marker bit which should be a 0
137 case 2: dest[j++]=1; break; // marker bit which should be a 1
138 default:
139 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
140 break;
141 }
142 bitCnt += pLen;
143 parityWd = 0;
144 }
145 // if we got here then all the parities passed
146 //return ID start index and size
147 return bitCnt;
148 }
149
150 uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) {
151 uint32_t num = 0;
152 for(int i = 0 ; i < numbits ; i++)
153 {
154 num = (num << 1) | (*src);
155 src++;
156 }
157 return num;
158 }
159
160 //least significant bit first
161 uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) {
162 uint32_t num = 0;
163 for(int i = 0 ; i < numbits ; i++)
164 {
165 num = (num << 1) | *(src + (numbits-(i+1)));
166 }
167 return num;
168 }
169
170 // 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
171 // fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
172 bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
173 // Sanity check. If preamble length is bigger than bitstream length.
174 if ( *size <= pLen ) return false;
175
176 uint8_t foundCnt = 0;
177 for (size_t idx = 0; idx < *size - pLen; idx++) {
178 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
179 //first index found
180 foundCnt++;
181 if (foundCnt == 1) {
182 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
183 *startIdx = idx;
184 if (findone) return true;
185 } else if (foundCnt == 2) {
186 *size = idx - *startIdx;
187 return true;
188 }
189 }
190 }
191 return false;
192 }
193
194 //by marshmellow
195 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
196 uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) {
197 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
198 }
199
200 // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
201 size_t findModStart(uint8_t dest[], size_t size, uint8_t expWaveSize) {
202 size_t i = 0;
203 size_t waveSizeCnt = 0;
204 uint8_t thresholdCnt = 0;
205 bool isAboveThreshold = dest[i++] >= FSK_PSK_THRESHOLD;
206 for (; i < size-20; i++ ) {
207 if(dest[i] < FSK_PSK_THRESHOLD && isAboveThreshold) {
208 thresholdCnt++;
209 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
210 isAboveThreshold = false;
211 waveSizeCnt = 0;
212 } else if (dest[i] >= FSK_PSK_THRESHOLD && !isAboveThreshold) {
213 thresholdCnt++;
214 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
215 isAboveThreshold = true;
216 waveSizeCnt = 0;
217 } else {
218 waveSizeCnt++;
219 }
220 if (thresholdCnt > 10) break;
221 }
222 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
223 return i;
224 }
225
226 int getClosestClock(int testclk) {
227 uint8_t fndClk[] = {8,16,32,40,50,64,128};
228
229 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++)
230 if (testclk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && testclk <= fndClk[clkCnt]+1)
231 return fndClk[clkCnt];
232
233 return 0;
234 }
235
236 void getNextLow(uint8_t samples[], size_t size, int low, size_t *i) {
237 while ((samples[*i] > low) && (*i < size))
238 *i+=1;
239 }
240
241 void getNextHigh(uint8_t samples[], size_t size, int high, size_t *i) {
242 while ((samples[*i] < high) && (*i < size))
243 *i+=1;
244 }
245
246 // load wave counters
247 bool loadWaveCounters(uint8_t samples[], size_t size, int lowToLowWaveLen[], int highToLowWaveLen[], int *waveCnt, int *skip, int *minClk, int *high, int *low) {
248 size_t i=0, firstLow, firstHigh;
249 size_t testsize = (size < 512) ? size : 512;
250
251 if ( getHiLo(samples, testsize, high, low, 80, 80) == -1 ) {
252 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
253 return false; //just noise
254 }
255
256 // get to first full low to prime loop and skip incomplete first pulse
257 getNextHigh(samples, size, *high, &i);
258 getNextLow(samples, size, *low, &i);
259 *skip = i;
260
261 // populate tmpbuff buffer with pulse lengths
262 while (i < size) {
263 // measure from low to low
264 firstLow = i;
265 //find first high point for this wave
266 getNextHigh(samples, size, *high, &i);
267 firstHigh = i;
268
269 getNextLow(samples, size, *low, &i);
270
271 if (*waveCnt >= (size/LOWEST_DEFAULT_CLOCK))
272 break;
273
274 highToLowWaveLen[*waveCnt] = i - firstHigh; //first high to first low
275 lowToLowWaveLen[*waveCnt] = i - firstLow;
276 *waveCnt += 1;
277 if (i-firstLow < *minClk && i < size) {
278 *minClk = i - firstLow;
279 }
280 }
281 return true;
282 }
283
284 //by marshmellow
285 //amplify based on ask edge detection - not accurate enough to use all the time
286 void askAmp(uint8_t *BitStream, size_t size) {
287 uint8_t Last = 128;
288 for(size_t i = 1; i<size; i++){
289 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
290 Last = 255;
291 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
292 Last = 0;
293
294 BitStream[i-1] = Last;
295 }
296 return;
297 }
298
299 uint32_t manchesterEncode2Bytes(uint16_t datain) {
300 uint32_t output = 0;
301 uint8_t curBit = 0;
302 for (uint8_t i=0; i<16; i++) {
303 curBit = (datain >> (15-i) & 1);
304 output |= (1<<(((15-i)*2)+curBit));
305 }
306 return output;
307 }
308
309 //by marshmellow
310 //encode binary data into binary manchester
311 //NOTE: BitStream must have triple the size of "size" available in memory to do the swap
312 int ManchesterEncode(uint8_t *BitStream, size_t size) {
313 //allow up to 4K out (means BitStream must be at least 2048+4096 to handle the swap)
314 size = (size>2048) ? 2048 : size;
315 size_t modIdx = size;
316 size_t i;
317 for (size_t idx=0; idx < size; idx++){
318 BitStream[idx+modIdx++] = BitStream[idx];
319 BitStream[idx+modIdx++] = BitStream[idx]^1;
320 }
321 for (i=0; i<(size*2); i++){
322 BitStream[i] = BitStream[i+size];
323 }
324 return i;
325 }
326
327 // by marshmellow
328 // to detect a wave that has heavily clipped (clean) samples
329 uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) {
330 bool allArePeaks = true;
331 uint16_t cntPeaks=0;
332 size_t loopEnd = 512+160;
333 if (loopEnd > size) loopEnd = size;
334 for (size_t i=160; i<loopEnd; i++){
335 if (dest[i]>low && dest[i]<high)
336 allArePeaks = false;
337 else
338 cntPeaks++;
339 }
340 if (!allArePeaks){
341 if (cntPeaks > 300) return true;
342 }
343 return allArePeaks;
344 }
345
346 //**********************************************************************************************
347 //-------------------Clock / Bitrate Detection Section------------------------------------------
348 //**********************************************************************************************
349
350 // by marshmellow
351 // to help detect clocks on heavily clipped samples
352 // based on count of low to low
353 int DetectStrongAskClock(uint8_t dest[], size_t size, int high, int low, int *clock) {
354 size_t startwave;
355 size_t i = 100;
356 size_t minClk = 255;
357 int shortestWaveIdx = 0;
358 // get to first full low to prime loop and skip incomplete first pulse
359 getNextHigh(dest, size, high, &i);
360 getNextLow(dest, size, low, &i);
361
362 // loop through all samples
363 while (i < size) {
364 // measure from low to low
365 startwave = i;
366
367 getNextHigh(dest, size, high, &i);
368 getNextLow(dest, size, low, &i);
369 //get minimum measured distance
370 if (i-startwave < minClk && i < size) {
371 minClk = i - startwave;
372 shortestWaveIdx = startwave;
373 }
374 }
375 // set clock
376 if (g_debugMode==2) prnt("DEBUG ASK: DetectStrongAskClock smallest wave: %d",minClk);
377 *clock = getClosestClock(minClk);
378 if (*clock == 0)
379 return 0;
380
381 return shortestWaveIdx;
382 }
383
384 // by marshmellow
385 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
386 // maybe somehow adjust peak trimming value based on samples to fix?
387 // return start index of best starting position for that clock and return clock (by reference)
388 int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) {
389 size_t i=1;
390 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
391 uint8_t clkEnd = 9;
392 uint8_t loopCnt = 255; //don't need to loop through entire array...
393 if (size <= loopCnt+60) return -1; //not enough samples
394 size -= 60; //sometimes there is a strange end wave - filter out this....
395 //if we already have a valid clock
396 uint8_t clockFnd=0;
397 for (;i<clkEnd;++i)
398 if (clk[i] == *clock) clockFnd = i;
399 //clock found but continue to find best startpos
400
401 //get high and low peak
402 int peak, low;
403 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
404
405 //test for large clean peaks
406 if (!clockFnd){
407 if (DetectCleanAskWave(dest, size, peak, low)==1){
408 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
409 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
410 if (ans > 0) {
411 return ans; //return shortest wave start position
412 }
413 }
414 }
415 uint8_t ii;
416 uint8_t clkCnt, tol = 0;
417 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
418 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
419 size_t errCnt = 0;
420 size_t arrLoc, loopEnd;
421
422 if (clockFnd>0) {
423 clkCnt = clockFnd;
424 clkEnd = clockFnd+1;
425 }
426 else clkCnt=1;
427
428 //test each valid clock from smallest to greatest to see which lines up
429 for(; clkCnt < clkEnd; clkCnt++){
430 if (clk[clkCnt] <= 32){
431 tol=1;
432 }else{
433 tol=0;
434 }
435 //if no errors allowed - keep start within the first clock
436 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
437 bestErr[clkCnt]=1000;
438 //try lining up the peaks by moving starting point (try first few clocks)
439 for (ii=0; ii < loopCnt; ii++){
440 if (dest[ii] < peak && dest[ii] > low) continue;
441
442 errCnt=0;
443 // now that we have the first one lined up test rest of wave array
444 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
445 for (i=0; i < loopEnd; ++i){
446 arrLoc = ii + (i * clk[clkCnt]);
447 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
448 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
449 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
450 }else{ //error no peak detected
451 errCnt++;
452 }
453 }
454 //if we found no errors then we can stop here and a low clock (common clocks)
455 // this is correct one - return this clock
456 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
457 if(errCnt==0 && clkCnt<7) {
458 if (!clockFnd) *clock = clk[clkCnt];
459 return ii;
460 }
461 //if we found errors see if it is lowest so far and save it as best run
462 if(errCnt<bestErr[clkCnt]){
463 bestErr[clkCnt]=errCnt;
464 bestStart[clkCnt]=ii;
465 }
466 }
467 }
468 uint8_t iii;
469 uint8_t best=0;
470 for (iii=1; iii<clkEnd; ++iii){
471 if (bestErr[iii] < bestErr[best]){
472 if (bestErr[iii] == 0) bestErr[iii]=1;
473 // current best bit to error ratio vs new bit to error ratio
474 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
475 best = iii;
476 }
477 }
478 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]);
479 }
480 if (!clockFnd) *clock = clk[best];
481 return bestStart[best];
482 }
483
484 int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
485 //find shortest transition from high to low
486 size_t i = 0;
487 size_t transition1 = 0;
488 int lowestTransition = 255;
489 bool lastWasHigh = false;
490
491 //find first valid beginning of a high or low wave
492 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
493 ++i;
494 while ((dest[i] < peak && dest[i] > low) && (i < size))
495 ++i;
496 lastWasHigh = (dest[i] >= peak);
497
498 if (i==size) return 0;
499 transition1 = i;
500
501 for (;i < size; i++) {
502 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
503 lastWasHigh = (dest[i] >= peak);
504 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
505 transition1 = i;
506 }
507 }
508 if (lowestTransition == 255) lowestTransition = 0;
509 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
510 return lowestTransition;
511 }
512
513 //by marshmellow
514 //detect nrz clock by reading #peaks vs no peaks(or errors)
515 int DetectNRZClock(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
516 size_t i=0;
517 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
518 size_t loopCnt = 4096; //don't need to loop through entire array...
519 if (size == 0) return 0;
520 if (size<loopCnt) loopCnt = size-20;
521 //if we already have a valid clock quit
522 for (; i < 8; ++i)
523 if (clk[i] == clock) return clock;
524
525 //get high and low peak
526 int peak, low;
527 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
528
529 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
530 size_t ii;
531 uint8_t clkCnt;
532 uint8_t tol = 0;
533 uint16_t smplCnt = 0;
534 int16_t peakcnt = 0;
535 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
536 uint16_t maxPeak = 255;
537 bool firstpeak = false;
538 //test for large clipped waves
539 for (i=0; i<loopCnt; i++){
540 if (dest[i] >= peak || dest[i] <= low){
541 if (!firstpeak) continue;
542 smplCnt++;
543 } else {
544 firstpeak=true;
545 if (smplCnt > 6 ){
546 if (maxPeak > smplCnt){
547 maxPeak = smplCnt;
548 //prnt("maxPk: %d",maxPeak);
549 }
550 peakcnt++;
551 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
552 smplCnt=0;
553 }
554 }
555 }
556 bool errBitHigh = 0;
557 bool bitHigh = 0;
558 uint8_t ignoreCnt = 0;
559 uint8_t ignoreWindow = 4;
560 bool lastPeakHigh = 0;
561 int lastBit = 0;
562 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
563 peakcnt=0;
564 //test each valid clock from smallest to greatest to see which lines up
565 for(clkCnt=0; clkCnt < 8; ++clkCnt){
566 //ignore clocks smaller than smallest peak
567 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
568 //try lining up the peaks by moving starting point (try first 256)
569 for (ii=20; ii < loopCnt; ++ii){
570 if ((dest[ii] >= peak) || (dest[ii] <= low)){
571 peakcnt = 0;
572 bitHigh = false;
573 ignoreCnt = 0;
574 lastBit = ii-clk[clkCnt];
575 //loop through to see if this start location works
576 for (i = ii; i < size-20; ++i) {
577 //if we are at a clock bit
578 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
579 //test high/low
580 if (dest[i] >= peak || dest[i] <= low) {
581 //if same peak don't count it
582 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
583 peakcnt++;
584 }
585 lastPeakHigh = (dest[i] >= peak);
586 bitHigh = true;
587 errBitHigh = false;
588 ignoreCnt = ignoreWindow;
589 lastBit += clk[clkCnt];
590 } else if (i == lastBit + clk[clkCnt] + tol) {
591 lastBit += clk[clkCnt];
592 }
593 //else if not a clock bit and no peaks
594 } else if (dest[i] < peak && dest[i] > low){
595 if (ignoreCnt==0){
596 bitHigh=false;
597 if (errBitHigh==true) peakcnt--;
598 errBitHigh=false;
599 } else {
600 ignoreCnt--;
601 }
602 // else if not a clock bit but we have a peak
603 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
604 //error bar found no clock...
605 errBitHigh=true;
606 }
607 }
608 if(peakcnt>peaksdet[clkCnt]) {
609 bestStart[clkCnt]=ii;
610 peaksdet[clkCnt]=peakcnt;
611 }
612 }
613 }
614 }
615 int iii=7;
616 uint8_t best=0;
617 for (iii=7; iii > 0; iii--){
618 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
619 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
620 best = iii;
621 }
622 } else if (peaksdet[iii] > peaksdet[best]){
623 best = iii;
624 }
625 if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition);
626 }
627 *clockStartIdx = bestStart[best];
628 return clk[best];
629 }
630
631 //by marshmellow
632 //countFC is to detect the field clock lengths.
633 //counts and returns the 2 most common wave lengths
634 //mainly used for FSK field clock detection
635 uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) {
636 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
637 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
638 uint8_t fcLensFnd = 0;
639 uint8_t lastFCcnt = 0;
640 uint8_t fcCounter = 0;
641 size_t i;
642 if (size < 180) return 0;
643
644 // prime i to first up transition
645 for (i = 160; i < size-20; i++)
646 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
647 break;
648
649 for (; i < size-20; i++){
650 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
651 // new up transition
652 fcCounter++;
653 if (fskAdj){
654 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
655 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
656 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
657 if ((fcCounter==9) || fcCounter==4) fcCounter++;
658 // save last field clock count (fc/xx)
659 lastFCcnt = fcCounter;
660 }
661 // find which fcLens to save it to:
662 for (int ii=0; ii<15; ii++){
663 if (fcLens[ii]==fcCounter){
664 fcCnts[ii]++;
665 fcCounter=0;
666 break;
667 }
668 }
669 if (fcCounter>0 && fcLensFnd<15){
670 //add new fc length
671 fcCnts[fcLensFnd]++;
672 fcLens[fcLensFnd++]=fcCounter;
673 }
674 fcCounter=0;
675 } else {
676 // count sample
677 fcCounter++;
678 }
679 }
680
681 uint8_t best1=14, best2=14, best3=14;
682 uint16_t maxCnt1=0;
683 // go through fclens and find which ones are bigest 2
684 for (i=0; i<15; i++){
685 // get the 3 best FC values
686 if (fcCnts[i]>maxCnt1) {
687 best3=best2;
688 best2=best1;
689 maxCnt1=fcCnts[i];
690 best1=i;
691 } else if(fcCnts[i]>fcCnts[best2]){
692 best3=best2;
693 best2=i;
694 } else if(fcCnts[i]>fcCnts[best3]){
695 best3=i;
696 }
697 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]);
698 }
699 if (fcLens[best1]==0) return 0;
700 uint8_t fcH=0, fcL=0;
701 if (fcLens[best1]>fcLens[best2]){
702 fcH=fcLens[best1];
703 fcL=fcLens[best2];
704 } else{
705 fcH=fcLens[best2];
706 fcL=fcLens[best1];
707 }
708 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
709 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]);
710 return 0; //lots of waves not psk or fsk
711 }
712 // TODO: take top 3 answers and compare to known Field clocks to get top 2
713
714 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
715 if (fskAdj) return fcs;
716 return fcLens[best1];
717 }
718
719 //by marshmellow
720 //detect psk clock by reading each phase shift
721 // a phase shift is determined by measuring the sample length of each wave
722 int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
723 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
724 uint16_t loopCnt = 4096; //don't need to loop through entire array...
725 if (size == 0) return 0;
726 if (size<loopCnt) loopCnt = size-20;
727
728 //if we already have a valid clock quit
729 size_t i=1;
730 for (; i < 8; ++i)
731 if (clk[i] == clock) return clock;
732
733 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
734 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
735 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
736 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
737 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
738 fc = countFC(dest, size, 0);
739 if (fc!=2 && fc!=4 && fc!=8) return -1;
740 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
741
742 //find first full wave
743 for (i=160; i<loopCnt; i++){
744 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
745 if (waveStart == 0) {
746 waveStart = i+1;
747 //prnt("DEBUG: waveStart: %d",waveStart);
748 } else {
749 waveEnd = i+1;
750 //prnt("DEBUG: waveEnd: %d",waveEnd);
751 waveLenCnt = waveEnd-waveStart;
752 if (waveLenCnt > fc){
753 firstFullWave = waveStart;
754 fullWaveLen=waveLenCnt;
755 break;
756 }
757 waveStart=0;
758 }
759 }
760 }
761 *firstPhaseShift = firstFullWave;
762 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
763 //test each valid clock from greatest to smallest to see which lines up
764 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
765 lastClkBit = firstFullWave; //set end of wave as clock align
766 waveStart = 0;
767 errCnt=0;
768 peakcnt=0;
769 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
770
771 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
772 //top edge of wave = start of new wave
773 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
774 if (waveStart == 0) {
775 waveStart = i+1;
776 waveLenCnt=0;
777 } else { //waveEnd
778 waveEnd = i+1;
779 waveLenCnt = waveEnd-waveStart;
780 if (waveLenCnt > fc){
781 //if this wave is a phase shift
782 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);
783 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
784 peakcnt++;
785 lastClkBit+=clk[clkCnt];
786 } else if (i<lastClkBit+8){
787 //noise after a phase shift - ignore
788 } else { //phase shift before supposed to based on clock
789 errCnt++;
790 }
791 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
792 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
793 }
794 waveStart=i+1;
795 }
796 }
797 }
798 if (errCnt == 0){
799 return clk[clkCnt];
800 }
801 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
802 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
803 }
804 //all tested with errors
805 //return the highest clk with the most peaks found
806 uint8_t best=7;
807 for (i=7; i>=1; i--){
808 if (peaksdet[i] > peaksdet[best]) {
809 best = i;
810 }
811 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
812 }
813 return clk[best];
814 }
815
816 int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
817 int firstPhaseShift = 0;
818 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
819 }
820
821 //by marshmellow
822 //detects the bit clock for FSK given the high and low Field Clocks
823 uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
824 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
825 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
826 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
827 uint8_t rfLensFnd = 0;
828 uint8_t lastFCcnt = 0;
829 uint16_t fcCounter = 0;
830 uint16_t rfCounter = 0;
831 uint8_t firstBitFnd = 0;
832 size_t i;
833 if (size == 0) return 0;
834
835 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
836 rfLensFnd=0;
837 fcCounter=0;
838 rfCounter=0;
839 firstBitFnd=0;
840 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
841 // prime i to first peak / up transition
842 for (i = 160; i < size-20; i++)
843 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
844 break;
845
846 for (; i < size-20; i++){
847 fcCounter++;
848 rfCounter++;
849
850 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
851 continue;
852 // else new peak
853 // if we got less than the small fc + tolerance then set it to the small fc
854 // if it is inbetween set it to the last counter
855 if (fcCounter < fcHigh && fcCounter > fcLow)
856 fcCounter = lastFCcnt;
857 else if (fcCounter < fcLow+fcTol)
858 fcCounter = fcLow;
859 else //set it to the large fc
860 fcCounter = fcHigh;
861
862 //look for bit clock (rf/xx)
863 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
864 //not the same size as the last wave - start of new bit sequence
865 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
866 for (int ii=0; ii<15; ii++){
867 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
868 rfCnts[ii]++;
869 rfCounter = 0;
870 break;
871 }
872 }
873 if (rfCounter > 0 && rfLensFnd < 15){
874 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
875 rfCnts[rfLensFnd]++;
876 rfLens[rfLensFnd++] = rfCounter;
877 }
878 } else {
879 *firstClockEdge = i;
880 firstBitFnd++;
881 }
882 rfCounter=0;
883 lastFCcnt=fcCounter;
884 }
885 fcCounter=0;
886 }
887 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
888
889 for (i=0; i<15; i++){
890 //get highest 2 RF values (might need to get more values to compare or compare all?)
891 if (rfCnts[i]>rfCnts[rfHighest]){
892 rfHighest3=rfHighest2;
893 rfHighest2=rfHighest;
894 rfHighest=i;
895 } else if(rfCnts[i]>rfCnts[rfHighest2]){
896 rfHighest3=rfHighest2;
897 rfHighest2=i;
898 } else if(rfCnts[i]>rfCnts[rfHighest3]){
899 rfHighest3=i;
900 }
901 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
902 }
903 // set allowed clock remainder tolerance to be 1 large field clock length+1
904 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
905 uint8_t tol1 = fcHigh+1;
906
907 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
908
909 // loop to find the highest clock that has a remainder less than the tolerance
910 // compare samples counted divided by
911 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
912 int ii=7;
913 for (; ii>=2; ii--){
914 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
915 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
916 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
917 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
918 break;
919 }
920 }
921 }
922 }
923
924 if (ii<2) return 0; // oops we went too far
925
926 return clk[ii];
927 }
928
929 uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
930 int firstClockEdge = 0;
931 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
932 }
933
934 //**********************************************************************************************
935 //--------------------Modulation Demods &/or Decoding Section-----------------------------------
936 //**********************************************************************************************
937
938 // 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...
939 bool findST(int *stStopLoc, int *stStartIdx, int lowToLowWaveLen[], int highToLowWaveLen[], int clk, int tol, int buffSize, size_t *i) {
940 for (; *i < buffSize - 4; *i+=1) {
941 *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...
942 if (lowToLowWaveLen[*i] >= clk*1-tol && lowToLowWaveLen[*i] <= (clk*2)+tol && highToLowWaveLen[*i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
943 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
944 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
945 if (lowToLowWaveLen[*i+3] >= clk*1-tol && lowToLowWaveLen[*i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
946 *stStopLoc = *i + 3;
947 return true;
948 }
949 }
950 }
951 }
952 }
953 return false;
954 }
955 //by marshmellow
956 //attempt to identify a Sequence Terminator in ASK modulated raw wave
957 bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
958 size_t bufsize = *size;
959 //need to loop through all samples and identify our clock, look for the ST pattern
960 int clk = 0;
961 int tol = 0;
962 int j, high, low, skip, start, end, minClk=255;
963 size_t i = 0;
964 //probably should malloc... || test if memory is available ... handle device side? memory danger!!! [marshmellow]
965 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
966 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...
967 //size_t testsize = (bufsize < 512) ? bufsize : 512;
968 int phaseoff = 0;
969 high = low = 128;
970 memset(tmpbuff, 0, sizeof(tmpbuff));
971 memset(waveLen, 0, sizeof(waveLen));
972
973 if (!loadWaveCounters(buffer, bufsize, tmpbuff, waveLen, &j, &skip, &minClk, &high, &low)) return false;
974 // set clock - might be able to get this externally and remove this work...
975 clk = getClosestClock(minClk);
976 // clock not found - ERROR
977 if (clk == 0) {
978 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
979 return false;
980 }
981 *foundclock = clk;
982
983 tol = clk/8;
984 if (!findST(&start, &skip, tmpbuff, waveLen, clk, tol, j, &i)) {
985 // first ST not found - ERROR
986 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
987 return false;
988 } else {
989 if (g_debugMode==2) prnt("DEBUG STT: first STT found at wave: %i, skip: %i, j=%i", start, skip, j);
990 }
991 if (waveLen[i+2] > clk*1+tol)
992 phaseoff = 0;
993 else
994 phaseoff = clk/2;
995
996 // skip over the remainder of ST
997 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
998
999 // now do it again to find the end
1000 int dummy1 = 0;
1001 end = skip;
1002 i+=3;
1003 if (!findST(&dummy1, &end, tmpbuff, waveLen, clk, tol, j, &i)) {
1004 //didn't find second ST - ERROR
1005 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1006 return false;
1007 }
1008 end -= phaseoff;
1009 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);
1010 //now begin to trim out ST so we can use normal demod cmds
1011 start = skip;
1012 size_t datalen = end - start;
1013 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1014 if ( clk - (datalen % clk) <= clk/8) {
1015 // padd the amount off - could be problematic... but shouldn't happen often
1016 datalen += clk - (datalen % clk);
1017 } else if ( (datalen % clk) <= clk/8 ) {
1018 // padd the amount off - could be problematic... but shouldn't happen often
1019 datalen -= datalen % clk;
1020 } else {
1021 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1022 return false;
1023 }
1024 // if datalen is less than one t55xx block - ERROR
1025 if (datalen/clk < 8*4) {
1026 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1027 return false;
1028 }
1029 size_t dataloc = start;
1030 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1031 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1032 for ( i=0; i <= (clk/8); ++i ) {
1033 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1034 dataloc -= i;
1035 break;
1036 }
1037 }
1038 }
1039
1040 size_t newloc = 0;
1041 i=0;
1042 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1043 bool firstrun = true;
1044 // warning - overwriting buffer given with raw wave data with ST removed...
1045 while ( dataloc < bufsize-(clk/2) ) {
1046 //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)
1047 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1048 for(i=0; i < clk/2-tol; ++i) {
1049 buffer[dataloc+i] = high+5;
1050 }
1051 } //test for single sample outlier (high between two lows) in the case of very strong waves
1052 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1053 buffer[dataloc] = buffer[dataloc+2];
1054 buffer[dataloc+1] = buffer[dataloc+2];
1055 }
1056 if (firstrun) {
1057 *stend = dataloc;
1058 *ststart = dataloc-(clk*4);
1059 firstrun=false;
1060 }
1061 for (i=0; i<datalen; ++i) {
1062 if (i+newloc < bufsize) {
1063 if (i+newloc < dataloc)
1064 buffer[i+newloc] = buffer[dataloc];
1065
1066 dataloc++;
1067 }
1068 }
1069 newloc += i;
1070 //skip next ST - we just assume it will be there from now on...
1071 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
1072 dataloc += clk*4;
1073 }
1074 *size = newloc;
1075 return true;
1076 }
1077 bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1078 size_t ststart = 0, stend = 0;
1079 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1080 }
1081
1082 //by marshmellow
1083 //take 11 10 01 11 00 and make 01100 ... miller decoding
1084 //check for phase errors - should never have half a 1 or 0 by itself and should never exceed 1111 or 0000 in a row
1085 //decodes miller encoded binary
1086 //NOTE askrawdemod will NOT demod miller encoded ask unless the clock is manually set to 1/2 what it is detected as!
1087 int millerRawDecode(uint8_t *BitStream, size_t *size, int invert) {
1088 if (*size < 16) return -1;
1089 uint16_t MaxBits = 512, errCnt = 0;
1090 size_t i, bitCnt=0;
1091 uint8_t alignCnt = 0, curBit = BitStream[0], alignedIdx = 0;
1092 uint8_t halfClkErr = 0;
1093 //find alignment, needs 4 1s or 0s to properly align
1094 for (i=1; i < *size-1; i++) {
1095 alignCnt = (BitStream[i] == curBit) ? alignCnt+1 : 0;
1096 curBit = BitStream[i];
1097 if (alignCnt == 4) break;
1098 }
1099 // for now error if alignment not found. later add option to run it with multiple offsets...
1100 if (alignCnt != 4) {
1101 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");
1102 return -1;
1103 }
1104 alignedIdx = (i-1) % 2;
1105 for (i=alignedIdx; i < *size-3; i+=2) {
1106 halfClkErr = (uint8_t)((halfClkErr << 1 | BitStream[i]) & 0xFF);
1107 if ( (halfClkErr & 0x7) == 5 || (halfClkErr & 0x7) == 2 || (i > 2 && (halfClkErr & 0x7) == 0) || (halfClkErr & 0x1F) == 0x1F) {
1108 errCnt++;
1109 BitStream[bitCnt++] = 7;
1110 continue;
1111 }
1112 BitStream[bitCnt++] = BitStream[i] ^ BitStream[i+1] ^ invert;
1113
1114 if (bitCnt > MaxBits) break;
1115 }
1116 *size = bitCnt;
1117 return errCnt;
1118 }
1119
1120 //by marshmellow
1121 //take 01 or 10 = 1 and 11 or 00 = 0
1122 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
1123 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1124 int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) {
1125 uint16_t bitnum = 0;
1126 uint16_t errCnt = 0;
1127 size_t i = offset;
1128 uint16_t MaxBits=512;
1129 //if not enough samples - error
1130 if (*size < 51) return -1;
1131 //check for phase change faults - skip one sample if faulty
1132 uint8_t offsetA = 1, offsetB = 1;
1133 for (; i<48; i+=2){
1134 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
1135 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
1136 }
1137 if (!offsetA && offsetB) offset++;
1138 for (i=offset; i<*size-3; i+=2){
1139 //check for phase error
1140 if (BitStream[i+1]==BitStream[i+2]) {
1141 BitStream[bitnum++]=7;
1142 errCnt++;
1143 }
1144 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1145 BitStream[bitnum++]=1^invert;
1146 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1147 BitStream[bitnum++]=invert;
1148 } else {
1149 BitStream[bitnum++]=7;
1150 errCnt++;
1151 }
1152 if(bitnum>MaxBits) break;
1153 }
1154 *size=bitnum;
1155 return errCnt;
1156 }
1157
1158 //by marshmellow
1159 //take 10 and 01 and manchester decode
1160 //run through 2 times and take least errCnt
1161 int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) {
1162 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
1163 size_t i, ii;
1164 uint16_t bestErr = 1000, bestRun = 0;
1165 if (*size < 16) return -1;
1166 //find correct start position [alignment]
1167 for (ii=0;ii<2;++ii){
1168 for (i=ii; i<*size-3; i+=2)
1169 if (BitStream[i]==BitStream[i+1])
1170 errCnt++;
1171
1172 if (bestErr>errCnt){
1173 bestErr=errCnt;
1174 bestRun=ii;
1175 }
1176 errCnt=0;
1177 }
1178 *alignPos=bestRun;
1179 //decode
1180 for (i=bestRun; i < *size-3; i+=2){
1181 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
1182 BitStream[bitnum++]=invert;
1183 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
1184 BitStream[bitnum++]=invert^1;
1185 } else {
1186 BitStream[bitnum++]=7;
1187 }
1188 if(bitnum>MaxBits) break;
1189 }
1190 *size=bitnum;
1191 return bestErr;
1192 }
1193
1194 //by marshmellow
1195 //demodulates strong heavily clipped samples
1196 int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
1197 {
1198 *startIdx=0;
1199 size_t bitCnt=0, smplCnt=1, errCnt=0;
1200 bool waveHigh = (BinStream[0] >= high);
1201 for (size_t i=1; i < *size; i++){
1202 if (BinStream[i] >= high && waveHigh){
1203 smplCnt++;
1204 } else if (BinStream[i] <= low && !waveHigh){
1205 smplCnt++;
1206 } else { //transition
1207 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
1208 if (smplCnt > clk-(clk/4)-1) { //full clock
1209 if (smplCnt > clk + (clk/4)+1) { //too many samples
1210 errCnt++;
1211 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1212 BinStream[bitCnt++] = 7;
1213 } else if (waveHigh) {
1214 BinStream[bitCnt++] = invert;
1215 BinStream[bitCnt++] = invert;
1216 } else if (!waveHigh) {
1217 BinStream[bitCnt++] = invert ^ 1;
1218 BinStream[bitCnt++] = invert ^ 1;
1219 }
1220 if (*startIdx==0) *startIdx = i-clk;
1221 waveHigh = !waveHigh;
1222 smplCnt = 0;
1223 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
1224 if (waveHigh) {
1225 BinStream[bitCnt++] = invert;
1226 } else if (!waveHigh) {
1227 BinStream[bitCnt++] = invert ^ 1;
1228 }
1229 if (*startIdx==0) *startIdx = i-(clk/2);
1230 waveHigh = !waveHigh;
1231 smplCnt = 0;
1232 } else {
1233 smplCnt++;
1234 //transition bit oops
1235 }
1236 } else { //haven't hit new high or new low yet
1237 smplCnt++;
1238 }
1239 }
1240 }
1241 *size = bitCnt;
1242 return errCnt;
1243 }
1244
1245 //by marshmellow
1246 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
1247 int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
1248 if (*size==0) return -1;
1249 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
1250 if (*clk==0 || start < 0) return -3;
1251 if (*invert != 1) *invert = 0;
1252 if (amp==1) askAmp(BinStream, *size);
1253 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
1254
1255 //start pos from detect ask clock is 1/2 clock offset
1256 // NOTE: can be negative (demod assumes rest of wave was there)
1257 *startIdx = start - (*clk/2);
1258 uint8_t initLoopMax = 255;
1259 if (initLoopMax > *size) initLoopMax = *size;
1260 // Detect high and lows
1261 //25% clip in case highs and lows aren't clipped [marshmellow]
1262 int high, low;
1263 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
1264 return -2; //just noise
1265
1266 size_t errCnt = 0;
1267 // if clean clipped waves detected run alternate demod
1268 if (DetectCleanAskWave(BinStream, *size, high, low)) {
1269 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
1270 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
1271 if (askType) { //askman
1272 uint8_t alignPos = 0;
1273 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
1274 *startIdx += *clk/2 * alignPos;
1275 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
1276 return errCnt;
1277 } else { //askraw
1278 return errCnt;
1279 }
1280 }
1281 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
1282 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
1283
1284 int lastBit; //set first clock check - can go negative
1285 size_t i, bitnum = 0; //output counter
1286 uint8_t midBit = 0;
1287 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
1288 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
1289 size_t MaxBits = 3072; //max bits to collect
1290 lastBit = start - *clk;
1291
1292 for (i = start; i < *size; ++i) {
1293 if (i-lastBit >= *clk-tol){
1294 if (BinStream[i] >= high) {
1295 BinStream[bitnum++] = *invert;
1296 } else if (BinStream[i] <= low) {
1297 BinStream[bitnum++] = *invert ^ 1;
1298 } else if (i-lastBit >= *clk+tol) {
1299 if (bitnum > 0) {
1300 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
1301 BinStream[bitnum++]=7;
1302 errCnt++;
1303 }
1304 } else { //in tolerance - looking for peak
1305 continue;
1306 }
1307 midBit = 0;
1308 lastBit += *clk;
1309 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
1310 if (BinStream[i] >= high) {
1311 BinStream[bitnum++] = *invert;
1312 } else if (BinStream[i] <= low) {
1313 BinStream[bitnum++] = *invert ^ 1;
1314 } else if (i-lastBit >= *clk/2+tol) {
1315 BinStream[bitnum] = BinStream[bitnum-1];
1316 bitnum++;
1317 } else { //in tolerance - looking for peak
1318 continue;
1319 }
1320 midBit = 1;
1321 }
1322 if (bitnum >= MaxBits) break;
1323 }
1324 *size = bitnum;
1325 return errCnt;
1326 }
1327
1328 int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
1329 int start = 0;
1330 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
1331 }
1332
1333 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1334 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1335 int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
1336 if (justNoise(dest, *size)) return -1;
1337 size_t clkStartIdx = 0;
1338 *clk = DetectNRZClock(dest, *size, *clk, &clkStartIdx);
1339 if (*clk==0) return -2;
1340 size_t i, gLen = 4096;
1341 if (gLen>*size) gLen = *size-20;
1342 int high, low;
1343 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
1344
1345 uint8_t bit=0;
1346 //convert wave samples to 1's and 0's
1347 for(i=20; i < *size-20; i++){
1348 if (dest[i] >= high) bit = 1;
1349 if (dest[i] <= low) bit = 0;
1350 dest[i] = bit;
1351 }
1352 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1353 size_t lastBit = 0;
1354 size_t numBits = 0;
1355 for(i=21; i < *size-20; i++) {
1356 //if transition detected or large number of same bits - store the passed bits
1357 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1358 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1359 numBits += (i - lastBit + (*clk/4)) / *clk;
1360 if (lastBit == 0) {
1361 *startIdx = i - (numBits * *clk);
1362 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1363 }
1364 lastBit = i-1;
1365 }
1366 }
1367 *size = numBits;
1368 return 0;
1369 }
1370
1371 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
1372 size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1373 size_t last_transition = 0;
1374 size_t idx = 1;
1375 if (fchigh==0) fchigh=10;
1376 if (fclow==0) fclow=8;
1377 //set the threshold close to 0 (graph) or 128 std to avoid static
1378 size_t preLastSample = 0;
1379 size_t LastSample = 0;
1380 size_t currSample = 0;
1381 if ( size < 1024 ) return 0; // not enough samples
1382
1383 //find start of modulating data in trace
1384 idx = findModStart(dest, size, fchigh);
1385 // Need to threshold first sample
1386 if(dest[idx] < FSK_PSK_THRESHOLD) dest[0] = 0;
1387 else dest[0] = 1;
1388
1389 last_transition = idx;
1390 idx++;
1391 size_t numBits = 0;
1392 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
1393 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
1394 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
1395 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
1396 for(; idx < size; idx++) {
1397 // threshold current value
1398 if (dest[idx] < FSK_PSK_THRESHOLD) dest[idx] = 0;
1399 else dest[idx] = 1;
1400
1401 // Check for 0->1 transition
1402 if (dest[idx-1] < dest[idx]) {
1403 preLastSample = LastSample;
1404 LastSample = currSample;
1405 currSample = idx-last_transition;
1406 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
1407 //do nothing with extra garbage
1408 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
1409 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
1410 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
1411 dest[numBits-1]=1;
1412 }
1413 dest[numBits++]=1;
1414 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1415 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
1416 //do nothing with beginning garbage and reset.. should be rare..
1417 numBits = 0;
1418 } 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)
1419 dest[numBits++]=1;
1420 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
1421 } else { //9+ = 10 sample waves (or 6+ = 7)
1422 dest[numBits++]=0;
1423 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
1424 }
1425 last_transition = idx;
1426 }
1427 }
1428 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
1429 }
1430
1431 //translate 11111100000 to 10
1432 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
1433 size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1434 uint8_t lastval=dest[0];
1435 size_t idx=0;
1436 size_t numBits=0;
1437 uint32_t n=1;
1438 for( idx=1; idx < size; idx++) {
1439 n++;
1440 if (dest[idx]==lastval) continue; //skip until we hit a transition
1441
1442 //find out how many bits (n) we collected (use 1/2 clk tolerance)
1443 //if lastval was 1, we have a 1->0 crossing
1444 if (dest[idx-1]==1) {
1445 n = (n * fclow + rfLen/2) / rfLen;
1446 } else {// 0->1 crossing
1447 n = (n * fchigh + rfLen/2) / rfLen;
1448 }
1449 if (n == 0) n = 1;
1450
1451 //first transition - save startidx
1452 if (numBits == 0) {
1453 if (lastval == 1) { //high to low
1454 *startIdx += (fclow * idx) - (n*rfLen);
1455 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
1456 } else {
1457 *startIdx += (fchigh * idx) - (n*rfLen);
1458 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
1459 }
1460 }
1461
1462 //add to our destination the bits we collected
1463 memset(dest+numBits, dest[idx-1]^invert , n);
1464 numBits += n;
1465 n=0;
1466 lastval=dest[idx];
1467 }//end for
1468 // if valid extra bits at the end were all the same frequency - add them in
1469 if (n > rfLen/fchigh) {
1470 if (dest[idx-2]==1) {
1471 n = (n * fclow + rfLen/2) / rfLen;
1472 } else {
1473 n = (n * fchigh + rfLen/2) / rfLen;
1474 }
1475 memset(dest+numBits, dest[idx-1]^invert , n);
1476 numBits += n;
1477 }
1478 return numBits;
1479 }
1480
1481 //by marshmellow (from holiman's base)
1482 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
1483 int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
1484 // FSK demodulator
1485 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
1486 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
1487 return size;
1488 }
1489
1490 int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
1491 int startIdx=0;
1492 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
1493 }
1494
1495 // by marshmellow
1496 // convert psk1 demod to psk2 demod
1497 // only transition waves are 1s
1498 void psk1TOpsk2(uint8_t *BitStream, size_t size) {
1499 size_t i=1;
1500 uint8_t lastBit=BitStream[0];
1501 for (; i<size; i++){
1502 if (BitStream[i]==7){
1503 //ignore errors
1504 } else if (lastBit!=BitStream[i]){
1505 lastBit=BitStream[i];
1506 BitStream[i]=1;
1507 } else {
1508 BitStream[i]=0;
1509 }
1510 }
1511 return;
1512 }
1513
1514 // by marshmellow
1515 // convert psk2 demod to psk1 demod
1516 // from only transition waves are 1s to phase shifts change bit
1517 void psk2TOpsk1(uint8_t *BitStream, size_t size) {
1518 uint8_t phase=0;
1519 for (size_t i=0; i<size; i++){
1520 if (BitStream[i]==1){
1521 phase ^=1;
1522 }
1523 BitStream[i]=phase;
1524 }
1525 return;
1526 }
1527
1528 size_t pskFindFirstPhaseShift(uint8_t samples[], size_t size, uint8_t *curPhase, size_t waveStart, uint16_t fc, uint16_t *fullWaveLen) {
1529 uint16_t loopCnt = (size+3 < 4096) ? size : 4096; //don't need to loop through entire array...
1530
1531 uint16_t avgWaveVal=0, lastAvgWaveVal=0;
1532 size_t i = waveStart, waveEnd, waveLenCnt, firstFullWave;
1533 for (; i<loopCnt; i++) {
1534 // find peak
1535 if (samples[i]+fc < samples[i+1] && samples[i+1] >= samples[i+2]){
1536 waveEnd = i+1;
1537 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u", waveEnd, waveStart);
1538 waveLenCnt = waveEnd-waveStart;
1539 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+8)){ //not first peak and is a large wave but not out of whack
1540 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1541 firstFullWave = waveStart;
1542 *fullWaveLen = waveLenCnt;
1543 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1544 if (lastAvgWaveVal > FSK_PSK_THRESHOLD) *curPhase ^= 1;
1545 return firstFullWave;
1546 }
1547 waveStart = i+1;
1548 avgWaveVal = 0;
1549 }
1550 avgWaveVal += samples[i+2];
1551 }
1552 return 0;
1553 }
1554
1555 //by marshmellow - demodulate PSK1 wave
1556 //uses wave lengths (# Samples)
1557 int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
1558 if (*size < 170) return -1;
1559
1560 uint8_t curPhase = *invert;
1561 size_t i=0, numBits=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1562 uint16_t fc=0, fullWaveLen=0, waveLenCnt=0, avgWaveVal, tol=1;
1563 uint16_t errCnt=0, errCnt2=0;
1564
1565 fc = countFC(dest, *size, 1);
1566 if ((fc >> 8) == 10) return -1; //fsk found - quit
1567 fc = fc & 0xFF;
1568 if (fc!=2 && fc!=4 && fc!=8) return -1;
1569 *clock = DetectPSKClock(dest, *size, *clock);
1570 if (*clock == 0) return -1;
1571
1572 //find start of modulating data in trace
1573 i = findModStart(dest, *size, fc);
1574
1575 //find first phase shift
1576 firstFullWave = pskFindFirstPhaseShift(dest, *size, &curPhase, i, fc, &fullWaveLen);
1577 if (firstFullWave == 0) {
1578 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1579 // so skip a little to ensure we are past any Start Signal
1580 firstFullWave = 160;
1581 memset(dest, curPhase, firstFullWave / *clock);
1582 } else {
1583 memset(dest, curPhase^1, firstFullWave / *clock);
1584 }
1585 //advance bits
1586 numBits += (firstFullWave / *clock);
1587 *startIdx = firstFullWave - (*clock * numBits)+2;
1588 //set start of wave as clock align
1589 lastClkBit = firstFullWave;
1590 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
1591 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
1592 waveStart = 0;
1593 dest[numBits++] = curPhase; //set first read bit
1594 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
1595 //top edge of wave = start of new wave
1596 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1597 if (waveStart == 0) {
1598 waveStart = i+1;
1599 waveLenCnt = 0;
1600 avgWaveVal = dest[i+1];
1601 } else { //waveEnd
1602 waveEnd = i+1;
1603 waveLenCnt = waveEnd-waveStart;
1604 if (waveLenCnt > fc){
1605 //this wave is a phase shift
1606 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1607 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
1608 curPhase ^= 1;
1609 dest[numBits++] = curPhase;
1610 lastClkBit += *clock;
1611 } else if (i < lastClkBit+10+fc){
1612 //noise after a phase shift - ignore
1613 } else { //phase shift before supposed to based on clock
1614 errCnt++;
1615 dest[numBits++] = 7;
1616 }
1617 } else if (i+1 > lastClkBit + *clock + tol + fc){
1618 lastClkBit += *clock; //no phase shift but clock bit
1619 dest[numBits++] = curPhase;
1620 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1621 errCnt2++;
1622 if(errCnt2 > 101) return errCnt2;
1623 }
1624 avgWaveVal = 0;
1625 waveStart = i+1;
1626 }
1627 }
1628 avgWaveVal += dest[i+1];
1629 }
1630 *size = numBits;
1631 return errCnt;
1632 }
1633
1634 int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1635 int startIdx = 0;
1636 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
1637 }
1638
1639 //**********************************************************************************************
1640 //-----------------Tag format detection section-------------------------------------------------
1641 //**********************************************************************************************
1642
1643 // by marshmellow
1644 // FSK Demod then try to locate an AWID ID
1645 int AWIDdemodFSK(uint8_t *dest, size_t *size) {
1646 //make sure buffer has enough data
1647 if (*size < 96*50) return -1;
1648
1649 if (justNoise(dest, *size)) return -2;
1650
1651 // FSK demodulator
1652 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1653 if (*size < 96) return -3; //did we get a good demod?
1654
1655 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
1656 size_t startIdx = 0;
1657 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1658 if (errChk == 0) return -4; //preamble not found
1659 if (*size != 96) return -5;
1660 return (int)startIdx;
1661 }
1662
1663 //by marshmellow
1664 //takes 1s and 0s and searches for EM410x format - output EM ID
1665 uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
1666 {
1667 //sanity checks
1668 if (*size < 64) return 0;
1669 if (BitStream[1]>1) return 0; //allow only 1s and 0s
1670
1671 // 111111111 bit pattern represent start of frame
1672 // include 0 in front to help get start pos
1673 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
1674 uint8_t errChk = 0;
1675 uint8_t FmtLen = 10; // sets of 4 bits = end data
1676 *startIdx = 0;
1677 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
1678 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
1679 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
1680
1681 //skip last 4bit parity row for simplicity
1682 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
1683 if (*size == 40) { // std em410x format
1684 *hi = 0;
1685 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
1686 } else if (*size == 88) { // long em format
1687 *hi = (bytebits_to_byte(BitStream, 24));
1688 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
1689 } else {
1690 return 0;
1691 }
1692 return 1;
1693 }
1694
1695 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
1696 // BitStream must contain previously askrawdemod and biphasedemoded data
1697 int FDXBdemodBI(uint8_t *dest, size_t *size) {
1698 //make sure buffer has enough data
1699 if (*size < 128) return -1;
1700
1701 size_t startIdx = 0;
1702 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
1703
1704 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1705 if (errChk == 0) return -2; //preamble not found
1706 if (*size != 128) return -3; //wrong size for fdxb
1707 //return start position
1708 return (int)startIdx;
1709 }
1710
1711 // by marshmellow
1712 // demod gProxIIDemod
1713 // error returns as -x
1714 // success returns start position in BitStream
1715 // BitStream must contain previously askrawdemod and biphasedemoded data
1716 int gProxII_Demod(uint8_t BitStream[], size_t *size) {
1717 size_t startIdx=0;
1718 uint8_t preamble[] = {1,1,1,1,1,0};
1719
1720 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
1721 if (errChk == 0) return -3; //preamble not found
1722 if (*size != 96) return -2; //should have found 96 bits
1723 //check first 6 spacer bits to verify format
1724 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
1725 //confirmed proper separator bits found
1726 //return start position
1727 return (int) startIdx;
1728 }
1729 return -5; //spacer bits not found - not a valid gproxII
1730 }
1731
1732 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
1733 int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1734 if (justNoise(dest, *size)) return -1;
1735
1736 size_t numStart=0, size2=*size, startIdx=0;
1737 // FSK demodulator
1738 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1739 if (*size < 96*2) return -2;
1740 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1741 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
1742 // find bitstring in array
1743 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1744 if (errChk == 0) return -3; //preamble not found
1745
1746 numStart = startIdx + sizeof(preamble);
1747 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1748 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1749 if (dest[idx] == dest[idx+1]){
1750 return -4; //not manchester data
1751 }
1752 *hi2 = (*hi2<<1)|(*hi>>31);
1753 *hi = (*hi<<1)|(*lo>>31);
1754 //Then, shift in a 0 or one into low
1755 if (dest[idx] && !dest[idx+1]) // 1 0
1756 *lo=(*lo<<1)|1;
1757 else // 0 1
1758 *lo=(*lo<<1)|0;
1759 }
1760 return (int)startIdx;
1761 }
1762
1763 int IOdemodFSK(uint8_t *dest, size_t size) {
1764 if (justNoise(dest, size)) return -1;
1765 //make sure buffer has data
1766 if (size < 66*64) return -2;
1767 // FSK demodulator
1768 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
1769 if (size < 65) return -3; //did we get a good demod?
1770 //Index map
1771 //0 10 20 30 40 50 60
1772 //| | | | | | |
1773 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
1774 //-----------------------------------------------------------------------------
1775 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
1776 //
1777 //XSF(version)facility:codeone+codetwo
1778 //Handle the data
1779 size_t startIdx = 0;
1780 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
1781 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
1782 if (errChk == 0) return -4; //preamble not found
1783
1784 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
1785 //confirmed proper separator bits found
1786 //return start position
1787 return (int) startIdx;
1788 }
1789 return -5;
1790 }
1791
1792 // redesigned by marshmellow adjusted from existing decode functions
1793 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1794 int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) {
1795 //26 bit 40134 format (don't know other formats)
1796 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};
1797 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};
1798 size_t startidx = 0;
1799 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1800 // if didn't find preamble try again inverting
1801 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1802 *invert ^= 1;
1803 }
1804 if (*size != 64 && *size != 224) return -2;
1805 if (*invert==1)
1806 for (size_t i = startidx; i < *size; i++)
1807 bitStream[i] ^= 1;
1808
1809 return (int) startidx;
1810 }
1811
1812 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
1813 int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) {
1814 if (justNoise(dest, *size)) return -1;
1815
1816 size_t numStart=0, size2=*size, startIdx=0;
1817 // FSK demodulator
1818 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
1819 if (*size < 96) return -2;
1820
1821 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
1822 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
1823
1824 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1825 if (errChk == 0) return -3; //preamble not found
1826
1827 numStart = startIdx + sizeof(preamble);
1828 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
1829 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
1830 if (dest[idx] == dest[idx+1])
1831 return -4; //not manchester data
1832 *hi2 = (*hi2<<1)|(*hi>>31);
1833 *hi = (*hi<<1)|(*lo>>31);
1834 //Then, shift in a 0 or one into low
1835 if (dest[idx] && !dest[idx+1]) // 1 0
1836 *lo=(*lo<<1)|1;
1837 else // 0 1
1838 *lo=(*lo<<1)|0;
1839 }
1840 return (int)startIdx;
1841 }
1842
1843 // find presco preamble 0x10D in already demoded data
1844 int PrescoDemod(uint8_t *dest, size_t *size) {
1845 //make sure buffer has data
1846 if (*size < 64*2) return -2;
1847
1848 size_t startIdx = 0;
1849 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
1850 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1851 if (errChk == 0) return -4; //preamble not found
1852 //return start position
1853 return (int) startIdx;
1854 }
1855
1856 // by marshmellow
1857 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
1858 int PyramiddemodFSK(uint8_t *dest, size_t *size) {
1859 //make sure buffer has data
1860 if (*size < 128*50) return -5;
1861
1862 //test samples are not just noise
1863 if (justNoise(dest, *size)) return -1;
1864
1865 // FSK demodulator
1866 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
1867 if (*size < 128) return -2; //did we get a good demod?
1868
1869 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
1870 size_t startIdx = 0;
1871 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1872 if (errChk == 0) return -4; //preamble not found
1873 if (*size != 128) return -3;
1874 return (int)startIdx;
1875 }
1876
1877 // by marshmellow
1878 // find viking preamble 0xF200 in already demoded data
1879 int VikingDemod_AM(uint8_t *dest, size_t *size) {
1880 //make sure buffer has data
1881 if (*size < 64*2) return -2;
1882
1883 size_t startIdx = 0;
1884 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};
1885 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
1886 if (errChk == 0) return -4; //preamble not found
1887 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
1888 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
1889 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
1890 if ( checkCalc != 0xA8 ) return -5;
1891 if (*size != 64) return -6;
1892 //return start position
1893 return (int) startIdx;
1894 }
1895
1896 // by iceman
1897 // find Visa2000 preamble in already demoded data
1898 int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1899 if (*size < 96) return -1; //make sure buffer has data
1900 size_t startIdx = 0;
1901 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};
1902 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1903 return -2; //preamble not found
1904 if (*size != 96) return -3; //wrong demoded size
1905 //return start position
1906 return (int)startIdx;
1907 }
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