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1 | //----------------------------------------------------------------------------- | |
2 | // Copyright (C) 2014 | |
3 | // | |
4 | // This code is licensed to you under the terms of the GNU GPL, version 2 or, | |
5 | // at your option, any later version. See the LICENSE.txt file for the text of | |
6 | // the license. | |
7 | //----------------------------------------------------------------------------- | |
8 | // Low frequency demod/decode commands | |
9 | //----------------------------------------------------------------------------- | |
10 | ||
11 | #include <stdlib.h> | |
12 | #include <string.h> | |
13 | #include "lfdemod.h" | |
14 | #include "common.h" | |
15 | ||
16 | /* //un_comment to allow debug print calls when used not on device | |
17 | void dummy(char *fmt, ...){} | |
18 | ||
19 | #ifndef ON_DEVICE | |
20 | #include "ui.h" | |
21 | #define prnt PrintAndLog | |
22 | #else | |
23 | ||
24 | #define prnt dummy | |
25 | #endif | |
26 | */ | |
27 | ||
28 | uint8_t justNoise(uint8_t *BitStream, size_t size) | |
29 | { | |
30 | static const uint8_t THRESHOLD = 123; | |
31 | //test samples are not just noise | |
32 | uint8_t justNoise1 = 1; | |
33 | for(size_t idx=0; idx < size && justNoise1 ;idx++){ | |
34 | justNoise1 = BitStream[idx] < THRESHOLD; | |
35 | } | |
36 | return justNoise1; | |
37 | } | |
38 | ||
39 | //by marshmellow | |
40 | //get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise | |
41 | int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) | |
42 | { | |
43 | *high=0; | |
44 | *low=255; | |
45 | // get high and low thresholds | |
46 | for (size_t i=0; i < size; i++){ | |
47 | if (BitStream[i] > *high) *high = BitStream[i]; | |
48 | if (BitStream[i] < *low) *low = BitStream[i]; | |
49 | } | |
50 | if (*high < 123) return -1; // just noise | |
51 | *high = ((*high-128)*fuzzHi + 12800)/100; | |
52 | *low = ((*low-128)*fuzzLo + 12800)/100; | |
53 | return 1; | |
54 | } | |
55 | ||
56 | // by marshmellow | |
57 | // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType | |
58 | // returns 1 if passed | |
59 | uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) | |
60 | { | |
61 | uint8_t ans = 0; | |
62 | for (uint8_t i = 0; i < bitLen; i++){ | |
63 | ans ^= ((bits >> i) & 1); | |
64 | } | |
65 | //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType); | |
66 | return (ans == pType); | |
67 | } | |
68 | ||
69 | //by marshmellow | |
70 | //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length | |
71 | uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) | |
72 | { | |
73 | uint8_t foundCnt=0; | |
74 | for (int idx=0; idx < *size - pLen; idx++){ | |
75 | if (memcmp(BitStream+idx, preamble, pLen) == 0){ | |
76 | //first index found | |
77 | foundCnt++; | |
78 | if (foundCnt == 1){ | |
79 | *startIdx = idx; | |
80 | } | |
81 | if (foundCnt == 2){ | |
82 | *size = idx - *startIdx; | |
83 | return 1; | |
84 | } | |
85 | } | |
86 | } | |
87 | return 0; | |
88 | } | |
89 | ||
90 | //by marshmellow | |
91 | //takes 1s and 0s and searches for EM410x format - output EM ID | |
92 | uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo) | |
93 | { | |
94 | //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future | |
95 | // otherwise could be a void with no arguments | |
96 | //set defaults | |
97 | uint32_t i = 0; | |
98 | if (BitStream[1]>1) return 0; //allow only 1s and 0s | |
99 | ||
100 | // 111111111 bit pattern represent start of frame | |
101 | // include 0 in front to help get start pos | |
102 | uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1}; | |
103 | uint32_t idx = 0; | |
104 | uint32_t parityBits = 0; | |
105 | uint8_t errChk = 0; | |
106 | uint8_t FmtLen = 10; | |
107 | *startIdx = 0; | |
108 | errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx); | |
109 | if (errChk == 0 || *size < 64) return 0; | |
110 | if (*size > 64) FmtLen = 22; | |
111 | *startIdx += 1; //get rid of 0 from preamble | |
112 | idx = *startIdx + 9; | |
113 | for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits) | |
114 | parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5); | |
115 | //check even parity - quit if failed | |
116 | if (parityTest(parityBits, 5, 0) == 0) return 0; | |
117 | //set uint64 with ID from BitStream | |
118 | for (uint8_t ii=0; ii<4; ii++){ | |
119 | *hi = (*hi << 1) | (*lo >> 63); | |
120 | *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]); | |
121 | } | |
122 | } | |
123 | if (errChk != 0) return 1; | |
124 | //skip last 5 bit parity test for simplicity. | |
125 | // *size = 64 | 128; | |
126 | return 0; | |
127 | } | |
128 | ||
129 | //by marshmellow | |
130 | //demodulates strong heavily clipped samples | |
131 | int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low) | |
132 | { | |
133 | size_t bitCnt=0, smplCnt=0, errCnt=0; | |
134 | uint8_t waveHigh = 0; | |
135 | for (size_t i=0; i < *size; i++){ | |
136 | if (BinStream[i] >= high && waveHigh){ | |
137 | smplCnt++; | |
138 | } else if (BinStream[i] <= low && !waveHigh){ | |
139 | smplCnt++; | |
140 | } else { //transition | |
141 | if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){ | |
142 | if (smplCnt > clk-(clk/4)-1) { //full clock | |
143 | if (smplCnt > clk + (clk/4)+1) { //too many samples | |
144 | errCnt++; | |
145 | BinStream[bitCnt++]=7; | |
146 | } else if (waveHigh) { | |
147 | BinStream[bitCnt++] = invert; | |
148 | BinStream[bitCnt++] = invert; | |
149 | } else if (!waveHigh) { | |
150 | BinStream[bitCnt++] = invert ^ 1; | |
151 | BinStream[bitCnt++] = invert ^ 1; | |
152 | } | |
153 | waveHigh ^= 1; | |
154 | smplCnt = 0; | |
155 | } else if (smplCnt > (clk/2) - (clk/4)-1) { | |
156 | if (waveHigh) { | |
157 | BinStream[bitCnt++] = invert; | |
158 | } else if (!waveHigh) { | |
159 | BinStream[bitCnt++] = invert ^ 1; | |
160 | } | |
161 | waveHigh ^= 1; | |
162 | smplCnt = 0; | |
163 | } else if (!bitCnt) { | |
164 | //first bit | |
165 | waveHigh = (BinStream[i] >= high); | |
166 | smplCnt = 1; | |
167 | } else { | |
168 | smplCnt++; | |
169 | //transition bit oops | |
170 | } | |
171 | } else { //haven't hit new high or new low yet | |
172 | smplCnt++; | |
173 | } | |
174 | } | |
175 | } | |
176 | *size = bitCnt; | |
177 | return errCnt; | |
178 | } | |
179 | ||
180 | //by marshmellow | |
181 | void askAmp(uint8_t *BitStream, size_t size) | |
182 | { | |
183 | for(size_t i = 1; i<size; i++){ | |
184 | if (BitStream[i]-BitStream[i-1]>=30) //large jump up | |
185 | BitStream[i]=127; | |
186 | else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down | |
187 | BitStream[i]=-127; | |
188 | } | |
189 | return; | |
190 | } | |
191 | ||
192 | //by marshmellow | |
193 | //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester | |
194 | int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) | |
195 | { | |
196 | if (*size==0) return -1; | |
197 | int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default | |
198 | if (*clk==0 || start < 0) return -3; | |
199 | if (*invert != 1) *invert = 0; | |
200 | if (amp==1) askAmp(BinStream, *size); | |
201 | ||
202 | uint8_t initLoopMax = 255; | |
203 | if (initLoopMax > *size) initLoopMax = *size; | |
204 | // Detect high and lows | |
205 | //25% clip in case highs and lows aren't clipped [marshmellow] | |
206 | int high, low; | |
207 | if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) | |
208 | return -2; //just noise | |
209 | ||
210 | size_t errCnt = 0; | |
211 | // if clean clipped waves detected run alternate demod | |
212 | if (DetectCleanAskWave(BinStream, *size, high, low)) { | |
213 | errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low); | |
214 | if (askType) //askman | |
215 | return manrawdecode(BinStream, size, 0); | |
216 | else //askraw | |
217 | return errCnt; | |
218 | } | |
219 | ||
220 | int lastBit; //set first clock check - can go negative | |
221 | size_t i, bitnum = 0; //output counter | |
222 | uint8_t midBit = 0; | |
223 | 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 | |
224 | 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 | |
225 | size_t MaxBits = 1024; | |
226 | lastBit = start - *clk; | |
227 | ||
228 | for (i = start; i < *size; ++i) { | |
229 | if (i-lastBit >= *clk-tol){ | |
230 | if (BinStream[i] >= high) { | |
231 | BinStream[bitnum++] = *invert; | |
232 | } else if (BinStream[i] <= low) { | |
233 | BinStream[bitnum++] = *invert ^ 1; | |
234 | } else if (i-lastBit >= *clk+tol) { | |
235 | if (bitnum > 0) { | |
236 | BinStream[bitnum++]=7; | |
237 | errCnt++; | |
238 | } | |
239 | } else { //in tolerance - looking for peak | |
240 | continue; | |
241 | } | |
242 | midBit = 0; | |
243 | lastBit += *clk; | |
244 | } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){ | |
245 | if (BinStream[i] >= high) { | |
246 | BinStream[bitnum++] = *invert; | |
247 | } else if (BinStream[i] <= low) { | |
248 | BinStream[bitnum++] = *invert ^ 1; | |
249 | } else if (i-lastBit >= *clk/2+tol) { | |
250 | BinStream[bitnum] = BinStream[bitnum-1]; | |
251 | bitnum++; | |
252 | } else { //in tolerance - looking for peak | |
253 | continue; | |
254 | } | |
255 | midBit = 1; | |
256 | } | |
257 | if (bitnum >= MaxBits) break; | |
258 | } | |
259 | *size = bitnum; | |
260 | return errCnt; | |
261 | } | |
262 | ||
263 | //by marshmellow | |
264 | //take 10 and 01 and manchester decode | |
265 | //run through 2 times and take least errCnt | |
266 | int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert) | |
267 | { | |
268 | uint16_t bitnum=0, MaxBits = 512, errCnt = 0; | |
269 | size_t i, ii; | |
270 | uint16_t bestErr = 1000, bestRun = 0; | |
271 | if (*size < 16) return -1; | |
272 | //find correct start position [alignment] | |
273 | for (ii=0;ii<2;++ii){ | |
274 | for (i=ii; i<*size-3; i+=2) | |
275 | if (BitStream[i]==BitStream[i+1]) | |
276 | errCnt++; | |
277 | ||
278 | if (bestErr>errCnt){ | |
279 | bestErr=errCnt; | |
280 | bestRun=ii; | |
281 | } | |
282 | errCnt=0; | |
283 | } | |
284 | //decode | |
285 | for (i=bestRun; i < *size-3; i+=2){ | |
286 | if(BitStream[i] == 1 && (BitStream[i+1] == 0)){ | |
287 | BitStream[bitnum++]=invert; | |
288 | } else if((BitStream[i] == 0) && BitStream[i+1] == 1){ | |
289 | BitStream[bitnum++]=invert^1; | |
290 | } else { | |
291 | BitStream[bitnum++]=7; | |
292 | } | |
293 | if(bitnum>MaxBits) break; | |
294 | } | |
295 | *size=bitnum; | |
296 | return bestErr; | |
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 | int ManchesterEncode(uint8_t *BitStream, size_t size) | |
312 | { | |
313 | size_t modIdx=20000, i=0; | |
314 | if (size>modIdx) return -1; | |
315 | for (size_t idx=0; idx < size; idx++){ | |
316 | BitStream[idx+modIdx++] = BitStream[idx]; | |
317 | BitStream[idx+modIdx++] = BitStream[idx]^1; | |
318 | } | |
319 | for (; i<(size*2); i++){ | |
320 | BitStream[i] = BitStream[i+20000]; | |
321 | } | |
322 | return i; | |
323 | } | |
324 | ||
325 | //by marshmellow | |
326 | //take 01 or 10 = 1 and 11 or 00 = 0 | |
327 | //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010 | |
328 | //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding | |
329 | int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) | |
330 | { | |
331 | uint16_t bitnum = 0; | |
332 | uint16_t errCnt = 0; | |
333 | size_t i = offset; | |
334 | uint16_t MaxBits=512; | |
335 | //if not enough samples - error | |
336 | if (*size < 51) return -1; | |
337 | //check for phase change faults - skip one sample if faulty | |
338 | uint8_t offsetA = 1, offsetB = 1; | |
339 | for (; i<48; i+=2){ | |
340 | if (BitStream[i+1]==BitStream[i+2]) offsetA=0; | |
341 | if (BitStream[i+2]==BitStream[i+3]) offsetB=0; | |
342 | } | |
343 | if (!offsetA && offsetB) offset++; | |
344 | for (i=offset; i<*size-3; i+=2){ | |
345 | //check for phase error | |
346 | if (BitStream[i+1]==BitStream[i+2]) { | |
347 | BitStream[bitnum++]=7; | |
348 | errCnt++; | |
349 | } | |
350 | if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){ | |
351 | BitStream[bitnum++]=1^invert; | |
352 | } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){ | |
353 | BitStream[bitnum++]=invert; | |
354 | } else { | |
355 | BitStream[bitnum++]=7; | |
356 | errCnt++; | |
357 | } | |
358 | if(bitnum>MaxBits) break; | |
359 | } | |
360 | *size=bitnum; | |
361 | return errCnt; | |
362 | } | |
363 | ||
364 | // by marshmellow | |
365 | // demod gProxIIDemod | |
366 | // error returns as -x | |
367 | // success returns start position in BitStream | |
368 | // BitStream must contain previously askrawdemod and biphasedemoded data | |
369 | int gProxII_Demod(uint8_t BitStream[], size_t *size) | |
370 | { | |
371 | size_t startIdx=0; | |
372 | uint8_t preamble[] = {1,1,1,1,1,0}; | |
373 | ||
374 | uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx); | |
375 | if (errChk == 0) return -3; //preamble not found | |
376 | if (*size != 96) return -2; //should have found 96 bits | |
377 | //check first 6 spacer bits to verify format | |
378 | if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){ | |
379 | //confirmed proper separator bits found | |
380 | //return start position | |
381 | return (int) startIdx; | |
382 | } | |
383 | return -5; | |
384 | } | |
385 | ||
386 | //translate wave to 11111100000 (1 for each short wave 0 for each long wave) | |
387 | size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow) | |
388 | { | |
389 | size_t last_transition = 0; | |
390 | size_t idx = 1; | |
391 | //uint32_t maxVal=0; | |
392 | if (fchigh==0) fchigh=10; | |
393 | if (fclow==0) fclow=8; | |
394 | //set the threshold close to 0 (graph) or 128 std to avoid static | |
395 | uint8_t threshold_value = 123; | |
396 | size_t preLastSample = 0; | |
397 | size_t LastSample = 0; | |
398 | size_t currSample = 0; | |
399 | // sync to first lo-hi transition, and threshold | |
400 | ||
401 | // Need to threshold first sample | |
402 | // skip 160 samples to allow antenna/samples to settle | |
403 | if(dest[160] < threshold_value) dest[0] = 0; | |
404 | else dest[0] = 1; | |
405 | ||
406 | size_t numBits = 0; | |
407 | // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8) | |
408 | // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere | |
409 | // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10 | |
410 | for(idx = 161; idx < size-20; idx++) { | |
411 | // threshold current value | |
412 | ||
413 | if (dest[idx] < threshold_value) dest[idx] = 0; | |
414 | else dest[idx] = 1; | |
415 | ||
416 | // Check for 0->1 transition | |
417 | if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition | |
418 | preLastSample = LastSample; | |
419 | LastSample = currSample; | |
420 | currSample = idx-last_transition; | |
421 | if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3) | |
422 | //do nothing with extra garbage | |
423 | } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves or 3-6 = 5 | |
424 | if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){ | |
425 | dest[numBits-1]=1; //correct previous 9 wave surrounded by 8 waves | |
426 | } | |
427 | dest[numBits++]=1; | |
428 | ||
429 | } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = garbage | |
430 | //do nothing with beginning garbage | |
431 | } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's | |
432 | dest[numBits++]=1; | |
433 | } else { //9+ = 10 sample waves | |
434 | dest[numBits++]=0; | |
435 | } | |
436 | last_transition = idx; | |
437 | } | |
438 | } | |
439 | return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0 | |
440 | } | |
441 | ||
442 | //translate 11111100000 to 10 | |
443 | size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, | |
444 | uint8_t invert, uint8_t fchigh, uint8_t fclow) | |
445 | { | |
446 | uint8_t lastval=dest[0]; | |
447 | size_t idx=0; | |
448 | size_t numBits=0; | |
449 | uint32_t n=1; | |
450 | for( idx=1; idx < size; idx++) { | |
451 | n++; | |
452 | if (dest[idx]==lastval) continue; | |
453 | ||
454 | //if lastval was 1, we have a 1->0 crossing | |
455 | if (dest[idx-1]==1) { | |
456 | n = (n * fclow + rfLen/2) / rfLen; | |
457 | } else {// 0->1 crossing | |
458 | n = (n * fchigh + rfLen/2) / rfLen; | |
459 | } | |
460 | if (n == 0) n = 1; | |
461 | ||
462 | memset(dest+numBits, dest[idx-1]^invert , n); | |
463 | numBits += n; | |
464 | n=0; | |
465 | lastval=dest[idx]; | |
466 | }//end for | |
467 | // if valid extra bits at the end were all the same frequency - add them in | |
468 | if (n > rfLen/fchigh) { | |
469 | if (dest[idx-2]==1) { | |
470 | n = (n * fclow + rfLen/2) / rfLen; | |
471 | } else { | |
472 | n = (n * fchigh + rfLen/2) / rfLen; | |
473 | } | |
474 | memset(dest+numBits, dest[idx-1]^invert , n); | |
475 | numBits += n; | |
476 | } | |
477 | return numBits; | |
478 | } | |
479 | ||
480 | //by marshmellow (from holiman's base) | |
481 | // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod) | |
482 | int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) | |
483 | { | |
484 | // FSK demodulator | |
485 | size = fsk_wave_demod(dest, size, fchigh, fclow); | |
486 | size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow); | |
487 | return size; | |
488 | } | |
489 | ||
490 | // loop to get raw HID waveform then FSK demodulate the TAG ID from it | |
491 | int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) | |
492 | { | |
493 | if (justNoise(dest, *size)) return -1; | |
494 | ||
495 | size_t numStart=0, size2=*size, startIdx=0; | |
496 | // FSK demodulator | |
497 | *size = fskdemod(dest, size2,50,1,10,8); //fsk2a | |
498 | if (*size < 96*2) return -2; | |
499 | // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 | |
500 | uint8_t preamble[] = {0,0,0,1,1,1,0,1}; | |
501 | // find bitstring in array | |
502 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
503 | if (errChk == 0) return -3; //preamble not found | |
504 | ||
505 | numStart = startIdx + sizeof(preamble); | |
506 | // final loop, go over previously decoded FSK data and manchester decode into usable tag ID | |
507 | for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ | |
508 | if (dest[idx] == dest[idx+1]){ | |
509 | return -4; //not manchester data | |
510 | } | |
511 | *hi2 = (*hi2<<1)|(*hi>>31); | |
512 | *hi = (*hi<<1)|(*lo>>31); | |
513 | //Then, shift in a 0 or one into low | |
514 | if (dest[idx] && !dest[idx+1]) // 1 0 | |
515 | *lo=(*lo<<1)|1; | |
516 | else // 0 1 | |
517 | *lo=(*lo<<1)|0; | |
518 | } | |
519 | return (int)startIdx; | |
520 | } | |
521 | ||
522 | // loop to get raw paradox waveform then FSK demodulate the TAG ID from it | |
523 | int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) | |
524 | { | |
525 | if (justNoise(dest, *size)) return -1; | |
526 | ||
527 | size_t numStart=0, size2=*size, startIdx=0; | |
528 | // FSK demodulator | |
529 | *size = fskdemod(dest, size2,50,1,10,8); //fsk2a | |
530 | if (*size < 96) return -2; | |
531 | ||
532 | // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 | |
533 | uint8_t preamble[] = {0,0,0,0,1,1,1,1}; | |
534 | ||
535 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
536 | if (errChk == 0) return -3; //preamble not found | |
537 | ||
538 | numStart = startIdx + sizeof(preamble); | |
539 | // final loop, go over previously decoded FSK data and manchester decode into usable tag ID | |
540 | for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ | |
541 | if (dest[idx] == dest[idx+1]) | |
542 | return -4; //not manchester data | |
543 | *hi2 = (*hi2<<1)|(*hi>>31); | |
544 | *hi = (*hi<<1)|(*lo>>31); | |
545 | //Then, shift in a 0 or one into low | |
546 | if (dest[idx] && !dest[idx+1]) // 1 0 | |
547 | *lo=(*lo<<1)|1; | |
548 | else // 0 1 | |
549 | *lo=(*lo<<1)|0; | |
550 | } | |
551 | return (int)startIdx; | |
552 | } | |
553 | ||
554 | uint32_t bytebits_to_byte(uint8_t* src, size_t numbits) | |
555 | { | |
556 | uint32_t num = 0; | |
557 | for(int i = 0 ; i < numbits ; i++) | |
558 | { | |
559 | num = (num << 1) | (*src); | |
560 | src++; | |
561 | } | |
562 | return num; | |
563 | } | |
564 | ||
565 | //least significant bit first | |
566 | uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) | |
567 | { | |
568 | uint32_t num = 0; | |
569 | for(int i = 0 ; i < numbits ; i++) | |
570 | { | |
571 | num = (num << 1) | *(src + (numbits-(i+1))); | |
572 | } | |
573 | return num; | |
574 | } | |
575 | ||
576 | int IOdemodFSK(uint8_t *dest, size_t size) | |
577 | { | |
578 | if (justNoise(dest, size)) return -1; | |
579 | //make sure buffer has data | |
580 | if (size < 66*64) return -2; | |
581 | // FSK demodulator | |
582 | size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64 | |
583 | if (size < 65) return -3; //did we get a good demod? | |
584 | //Index map | |
585 | //0 10 20 30 40 50 60 | |
586 | //| | | | | | | | |
587 | //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23 | |
588 | //----------------------------------------------------------------------------- | |
589 | //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11 | |
590 | // | |
591 | //XSF(version)facility:codeone+codetwo | |
592 | //Handle the data | |
593 | size_t startIdx = 0; | |
594 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1}; | |
595 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx); | |
596 | if (errChk == 0) return -4; //preamble not found | |
597 | ||
598 | if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){ | |
599 | //confirmed proper separator bits found | |
600 | //return start position | |
601 | return (int) startIdx; | |
602 | } | |
603 | return -5; | |
604 | } | |
605 | ||
606 | // by marshmellow | |
607 | // find viking preamble 0xF200 in already demoded data | |
608 | int VikingDemod_AM(uint8_t *dest, size_t *size) { | |
609 | //make sure buffer has data | |
610 | if (*size < 64*2) return -2; | |
611 | ||
612 | size_t startIdx = 0; | |
613 | 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}; | |
614 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
615 | if (errChk == 0) return -4; //preamble not found | |
616 | uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8) | |
617 | ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8) | |
618 | ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8); | |
619 | if ( checkCalc != 0xA8 ) return -5; | |
620 | if (*size != 64) return -6; | |
621 | //return start position | |
622 | return (int) startIdx; | |
623 | } | |
624 | ||
625 | // by marshmellow | |
626 | // takes a array of binary values, start position, length of bits per parity (includes parity bit), | |
627 | // Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run) | |
628 | size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) | |
629 | { | |
630 | uint32_t parityWd = 0; | |
631 | size_t j = 0, bitCnt = 0; | |
632 | for (int word = 0; word < (bLen); word+=pLen){ | |
633 | for (int bit=0; bit < pLen; bit++){ | |
634 | parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; | |
635 | BitStream[j++] = (BitStream[startIdx+word+bit]); | |
636 | } | |
637 | j--; // overwrite parity with next data | |
638 | // if parity fails then return 0 | |
639 | if (pType == 2) { // then marker bit which should be a 1 | |
640 | if (!BitStream[j]) return 0; | |
641 | } else { | |
642 | if (parityTest(parityWd, pLen, pType) == 0) return 0; | |
643 | } | |
644 | bitCnt+=(pLen-1); | |
645 | parityWd = 0; | |
646 | } | |
647 | // if we got here then all the parities passed | |
648 | //return ID start index and size | |
649 | return bitCnt; | |
650 | } | |
651 | ||
652 | // Ask/Biphase Demod then try to locate an ISO 11784/85 ID | |
653 | // BitStream must contain previously askrawdemod and biphasedemoded data | |
654 | int FDXBdemodBI(uint8_t *dest, size_t *size) | |
655 | { | |
656 | //make sure buffer has enough data | |
657 | if (*size < 128) return -1; | |
658 | ||
659 | size_t startIdx = 0; | |
660 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1}; | |
661 | ||
662 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
663 | if (errChk == 0) return -2; //preamble not found | |
664 | return (int)startIdx; | |
665 | } | |
666 | ||
667 | // by marshmellow | |
668 | // FSK Demod then try to locate an AWID ID | |
669 | int AWIDdemodFSK(uint8_t *dest, size_t *size) | |
670 | { | |
671 | //make sure buffer has enough data | |
672 | if (*size < 96*50) return -1; | |
673 | ||
674 | if (justNoise(dest, *size)) return -2; | |
675 | ||
676 | // FSK demodulator | |
677 | *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 | |
678 | if (*size < 96) return -3; //did we get a good demod? | |
679 | ||
680 | uint8_t preamble[] = {0,0,0,0,0,0,0,1}; | |
681 | size_t startIdx = 0; | |
682 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
683 | if (errChk == 0) return -4; //preamble not found | |
684 | if (*size != 96) return -5; | |
685 | return (int)startIdx; | |
686 | } | |
687 | ||
688 | // by marshmellow | |
689 | // FSK Demod then try to locate a Farpointe Data (pyramid) ID | |
690 | int PyramiddemodFSK(uint8_t *dest, size_t *size) | |
691 | { | |
692 | //make sure buffer has data | |
693 | if (*size < 128*50) return -5; | |
694 | ||
695 | //test samples are not just noise | |
696 | if (justNoise(dest, *size)) return -1; | |
697 | ||
698 | // FSK demodulator | |
699 | *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 | |
700 | if (*size < 128) return -2; //did we get a good demod? | |
701 | ||
702 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}; | |
703 | size_t startIdx = 0; | |
704 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
705 | if (errChk == 0) return -4; //preamble not found | |
706 | if (*size != 128) return -3; | |
707 | return (int)startIdx; | |
708 | } | |
709 | ||
710 | // by marshmellow | |
711 | // to detect a wave that has heavily clipped (clean) samples | |
712 | uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) | |
713 | { | |
714 | bool allArePeaks = true; | |
715 | uint16_t cntPeaks=0; | |
716 | size_t loopEnd = 512+160; | |
717 | if (loopEnd > size) loopEnd = size; | |
718 | for (size_t i=160; i<loopEnd; i++){ | |
719 | if (dest[i]>low && dest[i]<high) | |
720 | allArePeaks = false; | |
721 | else | |
722 | cntPeaks++; | |
723 | } | |
724 | if (!allArePeaks){ | |
725 | if (cntPeaks > 300) return true; | |
726 | } | |
727 | return allArePeaks; | |
728 | } | |
729 | // by marshmellow | |
730 | // to help detect clocks on heavily clipped samples | |
731 | // based on count of low to low | |
732 | int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low) | |
733 | { | |
734 | uint8_t fndClk[] = {8,16,32,40,50,64,128}; | |
735 | size_t startwave; | |
736 | size_t i = 100; | |
737 | size_t minClk = 255; | |
738 | // get to first full low to prime loop and skip incomplete first pulse | |
739 | while ((dest[i] < high) && (i < size)) | |
740 | ++i; | |
741 | while ((dest[i] > low) && (i < size)) | |
742 | ++i; | |
743 | ||
744 | // loop through all samples | |
745 | while (i < size) { | |
746 | // measure from low to low | |
747 | while ((dest[i] > low) && (i < size)) | |
748 | ++i; | |
749 | startwave= i; | |
750 | while ((dest[i] < high) && (i < size)) | |
751 | ++i; | |
752 | while ((dest[i] > low) && (i < size)) | |
753 | ++i; | |
754 | //get minimum measured distance | |
755 | if (i-startwave < minClk && i < size) | |
756 | minClk = i - startwave; | |
757 | } | |
758 | // set clock | |
759 | //prnt("minClk: %d",minClk); | |
760 | for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { | |
761 | if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) | |
762 | return fndClk[clkCnt]; | |
763 | } | |
764 | return 0; | |
765 | } | |
766 | ||
767 | // by marshmellow | |
768 | // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping) | |
769 | // maybe somehow adjust peak trimming value based on samples to fix? | |
770 | // return start index of best starting position for that clock and return clock (by reference) | |
771 | int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) | |
772 | { | |
773 | size_t i=1; | |
774 | uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255}; | |
775 | uint8_t clkEnd = 9; | |
776 | uint8_t loopCnt = 255; //don't need to loop through entire array... | |
777 | if (size <= loopCnt+60) return -1; //not enough samples | |
778 | size -= 60; //sometimes there is a strange end wave - filter out this.... | |
779 | //if we already have a valid clock | |
780 | uint8_t clockFnd=0; | |
781 | for (;i<clkEnd;++i) | |
782 | if (clk[i] == *clock) clockFnd = i; | |
783 | //clock found but continue to find best startpos | |
784 | ||
785 | //get high and low peak | |
786 | int peak, low; | |
787 | if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1; | |
788 | ||
789 | //test for large clean peaks | |
790 | if (!clockFnd){ | |
791 | if (DetectCleanAskWave(dest, size, peak, low)==1){ | |
792 | int ans = DetectStrongAskClock(dest, size, peak, low); | |
793 | for (i=clkEnd-1; i>0; i--){ | |
794 | if (clk[i] == ans) { | |
795 | *clock = ans; | |
796 | //clockFnd = i; | |
797 | return 0; // for strong waves i don't use the 'best start position' yet... | |
798 | //break; //clock found but continue to find best startpos [not yet] | |
799 | } | |
800 | } | |
801 | } | |
802 | } | |
803 | ||
804 | uint8_t ii; | |
805 | uint8_t clkCnt, tol = 0; | |
806 | uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; | |
807 | uint8_t bestStart[]={0,0,0,0,0,0,0,0,0}; | |
808 | size_t errCnt = 0; | |
809 | size_t arrLoc, loopEnd; | |
810 | ||
811 | if (clockFnd>0) { | |
812 | clkCnt = clockFnd; | |
813 | clkEnd = clockFnd+1; | |
814 | } | |
815 | else clkCnt=1; | |
816 | ||
817 | //test each valid clock from smallest to greatest to see which lines up | |
818 | for(; clkCnt < clkEnd; clkCnt++){ | |
819 | if (clk[clkCnt] <= 32){ | |
820 | tol=1; | |
821 | }else{ | |
822 | tol=0; | |
823 | } | |
824 | //if no errors allowed - keep start within the first clock | |
825 | if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2; | |
826 | bestErr[clkCnt]=1000; | |
827 | //try lining up the peaks by moving starting point (try first few clocks) | |
828 | for (ii=0; ii < loopCnt; ii++){ | |
829 | if (dest[ii] < peak && dest[ii] > low) continue; | |
830 | ||
831 | errCnt=0; | |
832 | // now that we have the first one lined up test rest of wave array | |
833 | loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1; | |
834 | for (i=0; i < loopEnd; ++i){ | |
835 | arrLoc = ii + (i * clk[clkCnt]); | |
836 | if (dest[arrLoc] >= peak || dest[arrLoc] <= low){ | |
837 | }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){ | |
838 | }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){ | |
839 | }else{ //error no peak detected | |
840 | errCnt++; | |
841 | } | |
842 | } | |
843 | //if we found no errors then we can stop here and a low clock (common clocks) | |
844 | // this is correct one - return this clock | |
845 | //prnt("DEBUG: clk %d, err %d, ii %d, i %d",clk[clkCnt],errCnt,ii,i); | |
846 | if(errCnt==0 && clkCnt<7) { | |
847 | if (!clockFnd) *clock = clk[clkCnt]; | |
848 | return ii; | |
849 | } | |
850 | //if we found errors see if it is lowest so far and save it as best run | |
851 | if(errCnt<bestErr[clkCnt]){ | |
852 | bestErr[clkCnt]=errCnt; | |
853 | bestStart[clkCnt]=ii; | |
854 | } | |
855 | } | |
856 | } | |
857 | uint8_t iii; | |
858 | uint8_t best=0; | |
859 | for (iii=1; iii<clkEnd; ++iii){ | |
860 | if (bestErr[iii] < bestErr[best]){ | |
861 | if (bestErr[iii] == 0) bestErr[iii]=1; | |
862 | // current best bit to error ratio vs new bit to error ratio | |
863 | if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){ | |
864 | best = iii; | |
865 | } | |
866 | } | |
867 | } | |
868 | //if (bestErr[best] > maxErr) return -1; | |
869 | if (!clockFnd) *clock = clk[best]; | |
870 | return bestStart[best]; | |
871 | } | |
872 | ||
873 | //by marshmellow | |
874 | //detect psk clock by reading each phase shift | |
875 | // a phase shift is determined by measuring the sample length of each wave | |
876 | int DetectPSKClock(uint8_t dest[], size_t size, int clock) | |
877 | { | |
878 | uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock | |
879 | uint16_t loopCnt = 4096; //don't need to loop through entire array... | |
880 | if (size == 0) return 0; | |
881 | if (size<loopCnt) loopCnt = size-20; | |
882 | ||
883 | //if we already have a valid clock quit | |
884 | size_t i=1; | |
885 | for (; i < 8; ++i) | |
886 | if (clk[i] == clock) return clock; | |
887 | ||
888 | size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0; | |
889 | uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1; | |
890 | uint16_t peakcnt=0, errCnt=0, waveLenCnt=0; | |
891 | uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; | |
892 | uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0}; | |
893 | fc = countFC(dest, size, 0); | |
894 | if (fc!=2 && fc!=4 && fc!=8) return -1; | |
895 | //prnt("DEBUG: FC: %d",fc); | |
896 | ||
897 | //find first full wave | |
898 | for (i=160; i<loopCnt; i++){ | |
899 | if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
900 | if (waveStart == 0) { | |
901 | waveStart = i+1; | |
902 | //prnt("DEBUG: waveStart: %d",waveStart); | |
903 | } else { | |
904 | waveEnd = i+1; | |
905 | //prnt("DEBUG: waveEnd: %d",waveEnd); | |
906 | waveLenCnt = waveEnd-waveStart; | |
907 | if (waveLenCnt > fc){ | |
908 | firstFullWave = waveStart; | |
909 | fullWaveLen=waveLenCnt; | |
910 | break; | |
911 | } | |
912 | waveStart=0; | |
913 | } | |
914 | } | |
915 | } | |
916 | //prnt("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen); | |
917 | ||
918 | //test each valid clock from greatest to smallest to see which lines up | |
919 | for(clkCnt=7; clkCnt >= 1 ; clkCnt--){ | |
920 | lastClkBit = firstFullWave; //set end of wave as clock align | |
921 | waveStart = 0; | |
922 | errCnt=0; | |
923 | peakcnt=0; | |
924 | //prnt("DEBUG: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit); | |
925 | ||
926 | for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){ | |
927 | //top edge of wave = start of new wave | |
928 | if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
929 | if (waveStart == 0) { | |
930 | waveStart = i+1; | |
931 | waveLenCnt=0; | |
932 | } else { //waveEnd | |
933 | waveEnd = i+1; | |
934 | waveLenCnt = waveEnd-waveStart; | |
935 | if (waveLenCnt > fc){ | |
936 | //if this wave is a phase shift | |
937 | //prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, ii: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,ii+1,fc); | |
938 | if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit | |
939 | peakcnt++; | |
940 | lastClkBit+=clk[clkCnt]; | |
941 | } else if (i<lastClkBit+8){ | |
942 | //noise after a phase shift - ignore | |
943 | } else { //phase shift before supposed to based on clock | |
944 | errCnt++; | |
945 | } | |
946 | } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){ | |
947 | lastClkBit+=clk[clkCnt]; //no phase shift but clock bit | |
948 | } | |
949 | waveStart=i+1; | |
950 | } | |
951 | } | |
952 | } | |
953 | if (errCnt == 0){ | |
954 | return clk[clkCnt]; | |
955 | } | |
956 | if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt; | |
957 | if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt; | |
958 | } | |
959 | //all tested with errors | |
960 | //return the highest clk with the most peaks found | |
961 | uint8_t best=7; | |
962 | for (i=7; i>=1; i--){ | |
963 | if (peaksdet[i] > peaksdet[best]) { | |
964 | best = i; | |
965 | } | |
966 | //prnt("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]); | |
967 | } | |
968 | return clk[best]; | |
969 | } | |
970 | ||
971 | int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){ | |
972 | //find shortest transition from high to low | |
973 | size_t i = 0; | |
974 | size_t transition1 = 0; | |
975 | int lowestTransition = 255; | |
976 | bool lastWasHigh = false; | |
977 | ||
978 | //find first valid beginning of a high or low wave | |
979 | while ((dest[i] >= peak || dest[i] <= low) && (i < size)) | |
980 | ++i; | |
981 | while ((dest[i] < peak && dest[i] > low) && (i < size)) | |
982 | ++i; | |
983 | lastWasHigh = (dest[i] >= peak); | |
984 | ||
985 | if (i==size) return 0; | |
986 | transition1 = i; | |
987 | ||
988 | for (;i < size; i++) { | |
989 | if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) { | |
990 | lastWasHigh = (dest[i] >= peak); | |
991 | if (i-transition1 < lowestTransition) lowestTransition = i-transition1; | |
992 | transition1 = i; | |
993 | } | |
994 | } | |
995 | //prnt("DEBUG: LowestTrs: %d",lowestTransition); | |
996 | if (lowestTransition == 255) lowestTransition = 0; | |
997 | return lowestTransition; | |
998 | } | |
999 | ||
1000 | //by marshmellow | |
1001 | //detect nrz clock by reading #peaks vs no peaks(or errors) | |
1002 | int DetectNRZClock(uint8_t dest[], size_t size, int clock) | |
1003 | { | |
1004 | size_t i=0; | |
1005 | uint8_t clk[]={8,16,32,40,50,64,100,128,255}; | |
1006 | size_t loopCnt = 4096; //don't need to loop through entire array... | |
1007 | if (size == 0) return 0; | |
1008 | if (size<loopCnt) loopCnt = size-20; | |
1009 | //if we already have a valid clock quit | |
1010 | for (; i < 8; ++i) | |
1011 | if (clk[i] == clock) return clock; | |
1012 | ||
1013 | //get high and low peak | |
1014 | int peak, low; | |
1015 | if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0; | |
1016 | ||
1017 | int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low); | |
1018 | size_t ii; | |
1019 | uint8_t clkCnt; | |
1020 | uint8_t tol = 0; | |
1021 | uint16_t smplCnt = 0; | |
1022 | int16_t peakcnt = 0; | |
1023 | int16_t peaksdet[] = {0,0,0,0,0,0,0,0}; | |
1024 | uint16_t maxPeak = 255; | |
1025 | bool firstpeak = false; | |
1026 | //test for large clipped waves | |
1027 | for (i=0; i<loopCnt; i++){ | |
1028 | if (dest[i] >= peak || dest[i] <= low){ | |
1029 | if (!firstpeak) continue; | |
1030 | smplCnt++; | |
1031 | } else { | |
1032 | firstpeak=true; | |
1033 | if (smplCnt > 6 ){ | |
1034 | if (maxPeak > smplCnt){ | |
1035 | maxPeak = smplCnt; | |
1036 | //prnt("maxPk: %d",maxPeak); | |
1037 | } | |
1038 | peakcnt++; | |
1039 | //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt); | |
1040 | smplCnt=0; | |
1041 | } | |
1042 | } | |
1043 | } | |
1044 | bool errBitHigh = 0; | |
1045 | bool bitHigh = 0; | |
1046 | uint8_t ignoreCnt = 0; | |
1047 | uint8_t ignoreWindow = 4; | |
1048 | bool lastPeakHigh = 0; | |
1049 | int lastBit = 0; | |
1050 | peakcnt=0; | |
1051 | //test each valid clock from smallest to greatest to see which lines up | |
1052 | for(clkCnt=0; clkCnt < 8; ++clkCnt){ | |
1053 | //ignore clocks smaller than smallest peak | |
1054 | if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue; | |
1055 | //try lining up the peaks by moving starting point (try first 256) | |
1056 | for (ii=20; ii < loopCnt; ++ii){ | |
1057 | if ((dest[ii] >= peak) || (dest[ii] <= low)){ | |
1058 | peakcnt=0; | |
1059 | bitHigh = false; | |
1060 | ignoreCnt = 0; | |
1061 | lastBit = ii-clk[clkCnt]; | |
1062 | //loop through to see if this start location works | |
1063 | for (i = ii; i < size-20; ++i) { | |
1064 | //if we are at a clock bit | |
1065 | if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) { | |
1066 | //test high/low | |
1067 | if (dest[i] >= peak || dest[i] <= low) { | |
1068 | //if same peak don't count it | |
1069 | if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) { | |
1070 | peakcnt++; | |
1071 | } | |
1072 | lastPeakHigh = (dest[i] >= peak); | |
1073 | bitHigh = true; | |
1074 | errBitHigh = false; | |
1075 | ignoreCnt = ignoreWindow; | |
1076 | lastBit += clk[clkCnt]; | |
1077 | } else if (i == lastBit + clk[clkCnt] + tol) { | |
1078 | lastBit += clk[clkCnt]; | |
1079 | } | |
1080 | //else if not a clock bit and no peaks | |
1081 | } else if (dest[i] < peak && dest[i] > low){ | |
1082 | if (ignoreCnt==0){ | |
1083 | bitHigh=false; | |
1084 | if (errBitHigh==true) peakcnt--; | |
1085 | errBitHigh=false; | |
1086 | } else { | |
1087 | ignoreCnt--; | |
1088 | } | |
1089 | // else if not a clock bit but we have a peak | |
1090 | } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) { | |
1091 | //error bar found no clock... | |
1092 | errBitHigh=true; | |
1093 | } | |
1094 | } | |
1095 | if(peakcnt>peaksdet[clkCnt]) { | |
1096 | peaksdet[clkCnt]=peakcnt; | |
1097 | } | |
1098 | } | |
1099 | } | |
1100 | } | |
1101 | int iii=7; | |
1102 | uint8_t best=0; | |
1103 | for (iii=7; iii > 0; iii--){ | |
1104 | if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) { | |
1105 | if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) { | |
1106 | best = iii; | |
1107 | } | |
1108 | } else if (peaksdet[iii] > peaksdet[best]){ | |
1109 | best = iii; | |
1110 | } | |
1111 | //prnt("DEBUG: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition); | |
1112 | } | |
1113 | ||
1114 | return clk[best]; | |
1115 | } | |
1116 | ||
1117 | // by marshmellow | |
1118 | // convert psk1 demod to psk2 demod | |
1119 | // only transition waves are 1s | |
1120 | void psk1TOpsk2(uint8_t *BitStream, size_t size) | |
1121 | { | |
1122 | size_t i=1; | |
1123 | uint8_t lastBit=BitStream[0]; | |
1124 | for (; i<size; i++){ | |
1125 | if (BitStream[i]==7){ | |
1126 | //ignore errors | |
1127 | } else if (lastBit!=BitStream[i]){ | |
1128 | lastBit=BitStream[i]; | |
1129 | BitStream[i]=1; | |
1130 | } else { | |
1131 | BitStream[i]=0; | |
1132 | } | |
1133 | } | |
1134 | return; | |
1135 | } | |
1136 | ||
1137 | // by marshmellow | |
1138 | // convert psk2 demod to psk1 demod | |
1139 | // from only transition waves are 1s to phase shifts change bit | |
1140 | void psk2TOpsk1(uint8_t *BitStream, size_t size) | |
1141 | { | |
1142 | uint8_t phase=0; | |
1143 | for (size_t i=0; i<size; i++){ | |
1144 | if (BitStream[i]==1){ | |
1145 | phase ^=1; | |
1146 | } | |
1147 | BitStream[i]=phase; | |
1148 | } | |
1149 | return; | |
1150 | } | |
1151 | ||
1152 | // redesigned by marshmellow adjusted from existing decode functions | |
1153 | // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more | |
1154 | int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) | |
1155 | { | |
1156 | //26 bit 40134 format (don't know other formats) | |
1157 | 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}; | |
1158 | 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}; | |
1159 | size_t startidx = 0; | |
1160 | if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){ | |
1161 | // if didn't find preamble try again inverting | |
1162 | if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1; | |
1163 | *invert ^= 1; | |
1164 | } | |
1165 | if (*size != 64 && *size != 224) return -2; | |
1166 | if (*invert==1) | |
1167 | for (size_t i = startidx; i < *size; i++) | |
1168 | bitStream[i] ^= 1; | |
1169 | ||
1170 | return (int) startidx; | |
1171 | } | |
1172 | ||
1173 | // by marshmellow - demodulate NRZ wave | |
1174 | // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak | |
1175 | int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){ | |
1176 | if (justNoise(dest, *size)) return -1; | |
1177 | *clk = DetectNRZClock(dest, *size, *clk); | |
1178 | if (*clk==0) return -2; | |
1179 | size_t i, gLen = 4096; | |
1180 | if (gLen>*size) gLen = *size-20; | |
1181 | int high, low; | |
1182 | if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low | |
1183 | ||
1184 | uint8_t bit=0; | |
1185 | //convert wave samples to 1's and 0's | |
1186 | for(i=20; i < *size-20; i++){ | |
1187 | if (dest[i] >= high) bit = 1; | |
1188 | if (dest[i] <= low) bit = 0; | |
1189 | dest[i] = bit; | |
1190 | } | |
1191 | //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit) | |
1192 | size_t lastBit = 0; | |
1193 | size_t numBits = 0; | |
1194 | for(i=21; i < *size-20; i++) { | |
1195 | //if transition detected or large number of same bits - store the passed bits | |
1196 | if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) { | |
1197 | memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk); | |
1198 | numBits += (i - lastBit + (*clk/4)) / *clk; | |
1199 | lastBit = i-1; | |
1200 | } | |
1201 | } | |
1202 | *size = numBits; | |
1203 | return 0; | |
1204 | } | |
1205 | ||
1206 | //by marshmellow | |
1207 | //detects the bit clock for FSK given the high and low Field Clocks | |
1208 | uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) | |
1209 | { | |
1210 | uint8_t clk[] = {8,16,32,40,50,64,100,128,0}; | |
1211 | uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1212 | uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1213 | uint8_t rfLensFnd = 0; | |
1214 | uint8_t lastFCcnt = 0; | |
1215 | uint16_t fcCounter = 0; | |
1216 | uint16_t rfCounter = 0; | |
1217 | uint8_t firstBitFnd = 0; | |
1218 | size_t i; | |
1219 | if (size == 0) return 0; | |
1220 | ||
1221 | uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2); | |
1222 | rfLensFnd=0; | |
1223 | fcCounter=0; | |
1224 | rfCounter=0; | |
1225 | firstBitFnd=0; | |
1226 | //PrintAndLog("DEBUG: fcTol: %d",fcTol); | |
1227 | // prime i to first peak / up transition | |
1228 | for (i = 160; i < size-20; i++) | |
1229 | if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]) | |
1230 | break; | |
1231 | ||
1232 | for (; i < size-20; i++){ | |
1233 | fcCounter++; | |
1234 | rfCounter++; | |
1235 | ||
1236 | if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1]) | |
1237 | continue; | |
1238 | // else new peak | |
1239 | // if we got less than the small fc + tolerance then set it to the small fc | |
1240 | if (fcCounter < fcLow+fcTol) | |
1241 | fcCounter = fcLow; | |
1242 | else //set it to the large fc | |
1243 | fcCounter = fcHigh; | |
1244 | ||
1245 | //look for bit clock (rf/xx) | |
1246 | if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){ | |
1247 | //not the same size as the last wave - start of new bit sequence | |
1248 | if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit | |
1249 | for (int ii=0; ii<15; ii++){ | |
1250 | if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){ | |
1251 | rfCnts[ii]++; | |
1252 | rfCounter = 0; | |
1253 | break; | |
1254 | } | |
1255 | } | |
1256 | if (rfCounter > 0 && rfLensFnd < 15){ | |
1257 | //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter); | |
1258 | rfCnts[rfLensFnd]++; | |
1259 | rfLens[rfLensFnd++] = rfCounter; | |
1260 | } | |
1261 | } else { | |
1262 | firstBitFnd++; | |
1263 | } | |
1264 | rfCounter=0; | |
1265 | lastFCcnt=fcCounter; | |
1266 | } | |
1267 | fcCounter=0; | |
1268 | } | |
1269 | uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15; | |
1270 | ||
1271 | for (i=0; i<15; i++){ | |
1272 | //prnt("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]); | |
1273 | //get highest 2 RF values (might need to get more values to compare or compare all?) | |
1274 | if (rfCnts[i]>rfCnts[rfHighest]){ | |
1275 | rfHighest3=rfHighest2; | |
1276 | rfHighest2=rfHighest; | |
1277 | rfHighest=i; | |
1278 | } else if(rfCnts[i]>rfCnts[rfHighest2]){ | |
1279 | rfHighest3=rfHighest2; | |
1280 | rfHighest2=i; | |
1281 | } else if(rfCnts[i]>rfCnts[rfHighest3]){ | |
1282 | rfHighest3=i; | |
1283 | } | |
1284 | } | |
1285 | // set allowed clock remainder tolerance to be 1 large field clock length+1 | |
1286 | // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off | |
1287 | uint8_t tol1 = fcHigh+1; | |
1288 | ||
1289 | //prnt("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]); | |
1290 | ||
1291 | // loop to find the highest clock that has a remainder less than the tolerance | |
1292 | // compare samples counted divided by | |
1293 | // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less) | |
1294 | int ii=7; | |
1295 | for (; ii>=2; ii--){ | |
1296 | if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){ | |
1297 | if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){ | |
1298 | if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){ | |
1299 | break; | |
1300 | } | |
1301 | } | |
1302 | } | |
1303 | } | |
1304 | ||
1305 | if (ii<0) return 0; // oops we went too far | |
1306 | ||
1307 | return clk[ii]; | |
1308 | } | |
1309 | ||
1310 | //by marshmellow | |
1311 | //countFC is to detect the field clock lengths. | |
1312 | //counts and returns the 2 most common wave lengths | |
1313 | //mainly used for FSK field clock detection | |
1314 | uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) | |
1315 | { | |
1316 | uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1317 | uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1318 | uint8_t fcLensFnd = 0; | |
1319 | uint8_t lastFCcnt=0; | |
1320 | uint8_t fcCounter = 0; | |
1321 | size_t i; | |
1322 | if (size == 0) return 0; | |
1323 | ||
1324 | // prime i to first up transition | |
1325 | for (i = 160; i < size-20; i++) | |
1326 | if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]) | |
1327 | break; | |
1328 | ||
1329 | for (; i < size-20; i++){ | |
1330 | if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){ | |
1331 | // new up transition | |
1332 | fcCounter++; | |
1333 | if (fskAdj){ | |
1334 | //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8) | |
1335 | if (lastFCcnt==5 && fcCounter==9) fcCounter--; | |
1336 | //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5) | |
1337 | if ((fcCounter==9) || fcCounter==4) fcCounter++; | |
1338 | // save last field clock count (fc/xx) | |
1339 | lastFCcnt = fcCounter; | |
1340 | } | |
1341 | // find which fcLens to save it to: | |
1342 | for (int ii=0; ii<15; ii++){ | |
1343 | if (fcLens[ii]==fcCounter){ | |
1344 | fcCnts[ii]++; | |
1345 | fcCounter=0; | |
1346 | break; | |
1347 | } | |
1348 | } | |
1349 | if (fcCounter>0 && fcLensFnd<15){ | |
1350 | //add new fc length | |
1351 | fcCnts[fcLensFnd]++; | |
1352 | fcLens[fcLensFnd++]=fcCounter; | |
1353 | } | |
1354 | fcCounter=0; | |
1355 | } else { | |
1356 | // count sample | |
1357 | fcCounter++; | |
1358 | } | |
1359 | } | |
1360 | ||
1361 | uint8_t best1=14, best2=14, best3=14; | |
1362 | uint16_t maxCnt1=0; | |
1363 | // go through fclens and find which ones are bigest 2 | |
1364 | for (i=0; i<15; i++){ | |
1365 | //prnt("DEBUG: FC %d, Cnt %d",fcLens[i],fcCnts[i]); | |
1366 | // get the 3 best FC values | |
1367 | if (fcCnts[i]>maxCnt1) { | |
1368 | best3=best2; | |
1369 | best2=best1; | |
1370 | maxCnt1=fcCnts[i]; | |
1371 | best1=i; | |
1372 | } else if(fcCnts[i]>fcCnts[best2]){ | |
1373 | best3=best2; | |
1374 | best2=i; | |
1375 | } else if(fcCnts[i]>fcCnts[best3]){ | |
1376 | best3=i; | |
1377 | } | |
1378 | } | |
1379 | if (fcLens[best1]==0) return 0; | |
1380 | uint8_t fcH=0, fcL=0; | |
1381 | if (fcLens[best1]>fcLens[best2]){ | |
1382 | fcH=fcLens[best1]; | |
1383 | fcL=fcLens[best2]; | |
1384 | } else{ | |
1385 | fcH=fcLens[best2]; | |
1386 | fcL=fcLens[best1]; | |
1387 | } | |
1388 | //prnt("DEBUG: dd %d > %d",(size-180)/fcH/3,fcCnts[best1]+fcCnts[best2]); | |
1389 | if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) return 0; //lots of waves not psk or fsk | |
1390 | ||
1391 | // TODO: take top 3 answers and compare to known Field clocks to get top 2 | |
1392 | ||
1393 | uint16_t fcs = (((uint16_t)fcH)<<8) | fcL; | |
1394 | //prnt("DEBUG: Best %d best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]); | |
1395 | if (fskAdj) return fcs; | |
1396 | return fcLens[best1]; | |
1397 | } | |
1398 | ||
1399 | //by marshmellow - demodulate PSK1 wave | |
1400 | //uses wave lengths (# Samples) | |
1401 | int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) | |
1402 | { | |
1403 | if (size == 0) return -1; | |
1404 | uint16_t loopCnt = 4096; //don't need to loop through entire array... | |
1405 | if (*size<loopCnt) loopCnt = *size; | |
1406 | ||
1407 | size_t numBits=0; | |
1408 | uint8_t curPhase = *invert; | |
1409 | size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0; | |
1410 | uint8_t fc=0, fullWaveLen=0, tol=1; | |
1411 | uint16_t errCnt=0, waveLenCnt=0; | |
1412 | fc = countFC(dest, *size, 0); | |
1413 | if (fc!=2 && fc!=4 && fc!=8) return -1; | |
1414 | //PrintAndLog("DEBUG: FC: %d",fc); | |
1415 | *clock = DetectPSKClock(dest, *size, *clock); | |
1416 | if (*clock == 0) return -1; | |
1417 | int avgWaveVal=0, lastAvgWaveVal=0; | |
1418 | //find first phase shift | |
1419 | for (i=0; i<loopCnt; i++){ | |
1420 | if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1421 | waveEnd = i+1; | |
1422 | //PrintAndLog("DEBUG: waveEnd: %d",waveEnd); | |
1423 | waveLenCnt = waveEnd-waveStart; | |
1424 | if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack | |
1425 | lastAvgWaveVal = avgWaveVal/(waveLenCnt); | |
1426 | firstFullWave = waveStart; | |
1427 | fullWaveLen=waveLenCnt; | |
1428 | //if average wave value is > graph 0 then it is an up wave or a 1 | |
1429 | if (lastAvgWaveVal > 123) curPhase ^= 1; //fudge graph 0 a little 123 vs 128 | |
1430 | break; | |
1431 | } | |
1432 | waveStart = i+1; | |
1433 | avgWaveVal = 0; | |
1434 | } | |
1435 | avgWaveVal += dest[i+2]; | |
1436 | } | |
1437 | if (firstFullWave == 0) { | |
1438 | // no phase shift detected - could be all 1's or 0's - doesn't matter where we start | |
1439 | // so skip a little to ensure we are past any Start Signal | |
1440 | firstFullWave = 160; | |
1441 | memset(dest, curPhase, firstFullWave / *clock); | |
1442 | } else { | |
1443 | memset(dest, curPhase^1, firstFullWave / *clock); | |
1444 | } | |
1445 | //advance bits | |
1446 | numBits += (firstFullWave / *clock); | |
1447 | //set start of wave as clock align | |
1448 | lastClkBit = firstFullWave; | |
1449 | //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen); | |
1450 | //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit); | |
1451 | waveStart = 0; | |
1452 | dest[numBits++] = curPhase; //set first read bit | |
1453 | for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){ | |
1454 | //top edge of wave = start of new wave | |
1455 | if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1456 | if (waveStart == 0) { | |
1457 | waveStart = i+1; | |
1458 | waveLenCnt = 0; | |
1459 | avgWaveVal = dest[i+1]; | |
1460 | } else { //waveEnd | |
1461 | waveEnd = i+1; | |
1462 | waveLenCnt = waveEnd-waveStart; | |
1463 | lastAvgWaveVal = avgWaveVal/waveLenCnt; | |
1464 | if (waveLenCnt > fc){ | |
1465 | //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal); | |
1466 | //this wave is a phase shift | |
1467 | //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc); | |
1468 | if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit | |
1469 | curPhase ^= 1; | |
1470 | dest[numBits++] = curPhase; | |
1471 | lastClkBit += *clock; | |
1472 | } else if (i < lastClkBit+10+fc){ | |
1473 | //noise after a phase shift - ignore | |
1474 | } else { //phase shift before supposed to based on clock | |
1475 | errCnt++; | |
1476 | dest[numBits++] = 7; | |
1477 | } | |
1478 | } else if (i+1 > lastClkBit + *clock + tol + fc){ | |
1479 | lastClkBit += *clock; //no phase shift but clock bit | |
1480 | dest[numBits++] = curPhase; | |
1481 | } | |
1482 | avgWaveVal = 0; | |
1483 | waveStart = i+1; | |
1484 | } | |
1485 | } | |
1486 | avgWaveVal += dest[i+1]; | |
1487 | } | |
1488 | *size = numBits; | |
1489 | return errCnt; | |
1490 | } |