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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 | uint8_t justNoise(uint8_t *BitStream, size_t size) | |
15 | { | |
16 | static const uint8_t THRESHOLD = 123; | |
17 | //test samples are not just noise | |
18 | uint8_t justNoise1 = 1; | |
19 | for(size_t idx=0; idx < size && justNoise1 ;idx++){ | |
20 | justNoise1 = BitStream[idx] < THRESHOLD; | |
21 | } | |
22 | return justNoise1; | |
23 | } | |
24 | ||
25 | //by marshmellow | |
26 | //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 | |
27 | int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo) | |
28 | { | |
29 | *high=0; | |
30 | *low=255; | |
31 | // get high and low thresholds | |
32 | for (size_t i=0; i < size; i++){ | |
33 | if (BitStream[i] > *high) *high = BitStream[i]; | |
34 | if (BitStream[i] < *low) *low = BitStream[i]; | |
35 | } | |
36 | if (*high < 123) return -1; // just noise | |
37 | *high = ((*high-128)*fuzzHi + 12800)/100; | |
38 | *low = ((*low-128)*fuzzLo + 12800)/100; | |
39 | return 1; | |
40 | } | |
41 | ||
42 | // by marshmellow | |
43 | // pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType | |
44 | // returns 1 if passed | |
45 | uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType) | |
46 | { | |
47 | uint8_t ans = 0; | |
48 | for (uint8_t i = 0; i < bitLen; i++){ | |
49 | ans ^= ((bits >> i) & 1); | |
50 | } | |
51 | //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType); | |
52 | return (ans == pType); | |
53 | } | |
54 | ||
55 | //by marshmellow | |
56 | //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length | |
57 | uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) | |
58 | { | |
59 | uint8_t foundCnt=0; | |
60 | for (int idx=0; idx < *size - pLen; idx++){ | |
61 | if (memcmp(BitStream+idx, preamble, pLen) == 0){ | |
62 | //first index found | |
63 | foundCnt++; | |
64 | if (foundCnt == 1){ | |
65 | *startIdx = idx; | |
66 | } | |
67 | if (foundCnt == 2){ | |
68 | *size = idx - *startIdx; | |
69 | return 1; | |
70 | } | |
71 | } | |
72 | } | |
73 | return 0; | |
74 | } | |
75 | ||
76 | //by marshmellow | |
77 | //takes 1s and 0s and searches for EM410x format - output EM ID | |
78 | uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo) | |
79 | { | |
80 | //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future | |
81 | // otherwise could be a void with no arguments | |
82 | //set defaults | |
83 | uint32_t i = 0; | |
84 | if (BitStream[1]>1) return 0; //allow only 1s and 0s | |
85 | ||
86 | // 111111111 bit pattern represent start of frame | |
87 | // include 0 in front to help get start pos | |
88 | uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1}; | |
89 | uint32_t idx = 0; | |
90 | uint32_t parityBits = 0; | |
91 | uint8_t errChk = 0; | |
92 | uint8_t FmtLen = 10; | |
93 | *startIdx = 0; | |
94 | errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx); | |
95 | if (errChk == 0 || *size < 64) return 0; | |
96 | if (*size > 64) FmtLen = 22; | |
97 | *startIdx += 1; //get rid of 0 from preamble | |
98 | idx = *startIdx + 9; | |
99 | for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits) | |
100 | parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5); | |
101 | //check even parity - quit if failed | |
102 | if (parityTest(parityBits, 5, 0) == 0) return 0; | |
103 | //set uint64 with ID from BitStream | |
104 | for (uint8_t ii=0; ii<4; ii++){ | |
105 | *hi = (*hi << 1) | (*lo >> 63); | |
106 | *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]); | |
107 | } | |
108 | } | |
109 | if (errChk != 0) return 1; | |
110 | //skip last 5 bit parity test for simplicity. | |
111 | // *size = 64 | 128; | |
112 | return 0; | |
113 | } | |
114 | ||
115 | //by marshmellow | |
116 | //demodulates strong heavily clipped samples | |
117 | int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low) | |
118 | { | |
119 | size_t bitCnt=0, smplCnt=0, errCnt=0; | |
120 | uint8_t waveHigh = 0; | |
121 | for (size_t i=0; i < *size; i++){ | |
122 | if (BinStream[i] >= high && waveHigh){ | |
123 | smplCnt++; | |
124 | } else if (BinStream[i] <= low && !waveHigh){ | |
125 | smplCnt++; | |
126 | } else { //transition | |
127 | if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){ | |
128 | if (smplCnt > clk-(clk/4)-1) { //full clock | |
129 | if (smplCnt > clk + (clk/4)+1) { //too many samples | |
130 | errCnt++; | |
131 | BinStream[bitCnt++]=7; | |
132 | } else if (waveHigh) { | |
133 | BinStream[bitCnt++] = invert; | |
134 | BinStream[bitCnt++] = invert; | |
135 | } else if (!waveHigh) { | |
136 | BinStream[bitCnt++] = invert ^ 1; | |
137 | BinStream[bitCnt++] = invert ^ 1; | |
138 | } | |
139 | waveHigh ^= 1; | |
140 | smplCnt = 0; | |
141 | } else if (smplCnt > (clk/2) - (clk/4)-1) { | |
142 | if (waveHigh) { | |
143 | BinStream[bitCnt++] = invert; | |
144 | } else if (!waveHigh) { | |
145 | BinStream[bitCnt++] = invert ^ 1; | |
146 | } | |
147 | waveHigh ^= 1; | |
148 | smplCnt = 0; | |
149 | } else if (!bitCnt) { | |
150 | //first bit | |
151 | waveHigh = (BinStream[i] >= high); | |
152 | smplCnt = 1; | |
153 | } else { | |
154 | smplCnt++; | |
155 | //transition bit oops | |
156 | } | |
157 | } else { //haven't hit new high or new low yet | |
158 | smplCnt++; | |
159 | } | |
160 | } | |
161 | } | |
162 | *size = bitCnt; | |
163 | return errCnt; | |
164 | } | |
165 | ||
166 | //by marshmellow | |
167 | void askAmp(uint8_t *BitStream, size_t size) | |
168 | { | |
169 | for(size_t i = 1; i<size; i++){ | |
170 | if (BitStream[i]-BitStream[i-1]>=30) //large jump up | |
171 | BitStream[i]=127; | |
172 | else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down | |
173 | BitStream[i]=-127; | |
174 | } | |
175 | return; | |
176 | } | |
177 | ||
178 | //by marshmellow | |
179 | //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester | |
180 | int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) | |
181 | { | |
182 | if (*size==0) return -1; | |
183 | int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default | |
184 | if (*clk==0 || start < 0) return -3; | |
185 | if (*invert != 1) *invert = 0; | |
186 | if (amp==1) askAmp(BinStream, *size); | |
187 | ||
188 | uint8_t initLoopMax = 255; | |
189 | if (initLoopMax > *size) initLoopMax = *size; | |
190 | // Detect high and lows | |
191 | //25% clip in case highs and lows aren't clipped [marshmellow] | |
192 | int high, low; | |
193 | if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) | |
194 | return -2; //just noise | |
195 | ||
196 | size_t errCnt = 0; | |
197 | // if clean clipped waves detected run alternate demod | |
198 | if (DetectCleanAskWave(BinStream, *size, high, low)) { | |
199 | errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low); | |
200 | if (askType) //askman | |
201 | return manrawdecode(BinStream, size, 0); | |
202 | else //askraw | |
203 | return errCnt; | |
204 | } | |
205 | ||
206 | int lastBit; //set first clock check - can go negative | |
207 | size_t i, bitnum = 0; //output counter | |
208 | uint8_t midBit = 0; | |
209 | 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 | |
210 | 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 | |
211 | size_t MaxBits = 1024; | |
212 | lastBit = start - *clk; | |
213 | ||
214 | for (i = start; i < *size; ++i) { | |
215 | if (i-lastBit >= *clk-tol){ | |
216 | if (BinStream[i] >= high) { | |
217 | BinStream[bitnum++] = *invert; | |
218 | } else if (BinStream[i] <= low) { | |
219 | BinStream[bitnum++] = *invert ^ 1; | |
220 | } else if (i-lastBit >= *clk+tol) { | |
221 | if (bitnum > 0) { | |
222 | BinStream[bitnum++]=7; | |
223 | errCnt++; | |
224 | } | |
225 | } else { //in tolerance - looking for peak | |
226 | continue; | |
227 | } | |
228 | midBit = 0; | |
229 | lastBit += *clk; | |
230 | } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){ | |
231 | if (BinStream[i] >= high) { | |
232 | BinStream[bitnum++] = *invert; | |
233 | } else if (BinStream[i] <= low) { | |
234 | BinStream[bitnum++] = *invert ^ 1; | |
235 | } else if (i-lastBit >= *clk/2+tol) { | |
236 | BinStream[bitnum] = BinStream[bitnum-1]; | |
237 | bitnum++; | |
238 | } else { //in tolerance - looking for peak | |
239 | continue; | |
240 | } | |
241 | midBit = 1; | |
242 | } | |
243 | if (bitnum >= MaxBits) break; | |
244 | } | |
245 | *size = bitnum; | |
246 | return errCnt; | |
247 | } | |
248 | ||
249 | //by marshmellow | |
250 | //take 10 and 01 and manchester decode | |
251 | //run through 2 times and take least errCnt | |
252 | int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert) | |
253 | { | |
254 | uint16_t bitnum=0, MaxBits = 512, errCnt = 0; | |
255 | size_t i, ii; | |
256 | uint16_t bestErr = 1000, bestRun = 0; | |
257 | if (*size < 16) return -1; | |
258 | //find correct start position [alignment] | |
259 | for (ii=0;ii<2;++ii){ | |
260 | for (i=ii; i<*size-3; i+=2) | |
261 | if (BitStream[i]==BitStream[i+1]) | |
262 | errCnt++; | |
263 | ||
264 | if (bestErr>errCnt){ | |
265 | bestErr=errCnt; | |
266 | bestRun=ii; | |
267 | } | |
268 | errCnt=0; | |
269 | } | |
270 | //decode | |
271 | for (i=bestRun; i < *size-3; i+=2){ | |
272 | if(BitStream[i] == 1 && (BitStream[i+1] == 0)){ | |
273 | BitStream[bitnum++]=invert; | |
274 | } else if((BitStream[i] == 0) && BitStream[i+1] == 1){ | |
275 | BitStream[bitnum++]=invert^1; | |
276 | } else { | |
277 | BitStream[bitnum++]=7; | |
278 | } | |
279 | if(bitnum>MaxBits) break; | |
280 | } | |
281 | *size=bitnum; | |
282 | return bestErr; | |
283 | } | |
284 | ||
285 | uint32_t manchesterEncode2Bytes(uint16_t datain) { | |
286 | uint32_t output = 0; | |
287 | uint8_t curBit = 0; | |
288 | for (uint8_t i=0; i<16; i++) { | |
289 | curBit = (datain >> (15-i) & 1); | |
290 | output |= (1<<(((15-i)*2)+curBit)); | |
291 | } | |
292 | return output; | |
293 | } | |
294 | ||
295 | //by marshmellow | |
296 | //encode binary data into binary manchester | |
297 | int ManchesterEncode(uint8_t *BitStream, size_t size) | |
298 | { | |
299 | size_t modIdx=20000, i=0; | |
300 | if (size>modIdx) return -1; | |
301 | for (size_t idx=0; idx < size; idx++){ | |
302 | BitStream[idx+modIdx++] = BitStream[idx]; | |
303 | BitStream[idx+modIdx++] = BitStream[idx]^1; | |
304 | } | |
305 | for (; i<(size*2); i++){ | |
306 | BitStream[i] = BitStream[i+20000]; | |
307 | } | |
308 | return i; | |
309 | } | |
310 | ||
311 | //by marshmellow | |
312 | //take 01 or 10 = 1 and 11 or 00 = 0 | |
313 | //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010 | |
314 | //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding | |
315 | int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) | |
316 | { | |
317 | uint16_t bitnum = 0; | |
318 | uint16_t errCnt = 0; | |
319 | size_t i = offset; | |
320 | uint16_t MaxBits=512; | |
321 | //if not enough samples - error | |
322 | if (*size < 51) return -1; | |
323 | //check for phase change faults - skip one sample if faulty | |
324 | uint8_t offsetA = 1, offsetB = 1; | |
325 | for (; i<48; i+=2){ | |
326 | if (BitStream[i+1]==BitStream[i+2]) offsetA=0; | |
327 | if (BitStream[i+2]==BitStream[i+3]) offsetB=0; | |
328 | } | |
329 | if (!offsetA && offsetB) offset++; | |
330 | for (i=offset; i<*size-3; i+=2){ | |
331 | //check for phase error | |
332 | if (BitStream[i+1]==BitStream[i+2]) { | |
333 | BitStream[bitnum++]=7; | |
334 | errCnt++; | |
335 | } | |
336 | if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){ | |
337 | BitStream[bitnum++]=1^invert; | |
338 | } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){ | |
339 | BitStream[bitnum++]=invert; | |
340 | } else { | |
341 | BitStream[bitnum++]=7; | |
342 | errCnt++; | |
343 | } | |
344 | if(bitnum>MaxBits) break; | |
345 | } | |
346 | *size=bitnum; | |
347 | return errCnt; | |
348 | } | |
349 | ||
350 | // by marshmellow | |
351 | // demod gProxIIDemod | |
352 | // error returns as -x | |
353 | // success returns start position in BitStream | |
354 | // BitStream must contain previously askrawdemod and biphasedemoded data | |
355 | int gProxII_Demod(uint8_t BitStream[], size_t *size) | |
356 | { | |
357 | size_t startIdx=0; | |
358 | uint8_t preamble[] = {1,1,1,1,1,0}; | |
359 | ||
360 | uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx); | |
361 | if (errChk == 0) return -3; //preamble not found | |
362 | if (*size != 96) return -2; //should have found 96 bits | |
363 | //check first 6 spacer bits to verify format | |
364 | if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){ | |
365 | //confirmed proper separator bits found | |
366 | //return start position | |
367 | return (int) startIdx; | |
368 | } | |
369 | return -5; | |
370 | } | |
371 | ||
372 | //translate wave to 11111100000 (1 for each short wave 0 for each long wave) | |
373 | size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow) | |
374 | { | |
375 | size_t last_transition = 0; | |
376 | size_t idx = 1; | |
377 | //uint32_t maxVal=0; | |
378 | if (fchigh==0) fchigh=10; | |
379 | if (fclow==0) fclow=8; | |
380 | //set the threshold close to 0 (graph) or 128 std to avoid static | |
381 | uint8_t threshold_value = 123; | |
382 | size_t preLastSample = 0; | |
383 | size_t LastSample = 0; | |
384 | size_t currSample = 0; | |
385 | // sync to first lo-hi transition, and threshold | |
386 | ||
387 | // Need to threshold first sample | |
388 | ||
389 | if(dest[0] < threshold_value) dest[0] = 0; | |
390 | else dest[0] = 1; | |
391 | ||
392 | size_t numBits = 0; | |
393 | // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8) | |
394 | // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere | |
395 | // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10 | |
396 | for(idx = 1; idx < size; idx++) { | |
397 | // threshold current value | |
398 | ||
399 | if (dest[idx] < threshold_value) dest[idx] = 0; | |
400 | else dest[idx] = 1; | |
401 | ||
402 | // Check for 0->1 transition | |
403 | if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition | |
404 | preLastSample = LastSample; | |
405 | LastSample = currSample; | |
406 | currSample = idx-last_transition; | |
407 | if (currSample < (fclow-2)){ //0-5 = garbage noise | |
408 | //do nothing with extra garbage | |
409 | } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves | |
410 | if (LastSample > (fchigh-2) && preLastSample < (fchigh-1)){ | |
411 | dest[numBits-1]=1; //correct last 9 wave surrounded by 8 waves | |
412 | } | |
413 | dest[numBits++]=1; | |
414 | ||
415 | } else if (currSample > (fchigh+1) && !numBits) { //12 + and first bit = garbage | |
416 | //do nothing with beginning garbage | |
417 | } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's | |
418 | dest[numBits++]=1; | |
419 | } else { //9+ = 10 sample waves | |
420 | dest[numBits++]=0; | |
421 | } | |
422 | last_transition = idx; | |
423 | } | |
424 | } | |
425 | return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0 | |
426 | } | |
427 | ||
428 | //translate 11111100000 to 10 | |
429 | size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, | |
430 | uint8_t invert, uint8_t fchigh, uint8_t fclow) | |
431 | { | |
432 | uint8_t lastval=dest[0]; | |
433 | size_t idx=0; | |
434 | size_t numBits=0; | |
435 | uint32_t n=1; | |
436 | for( idx=1; idx < size; idx++) { | |
437 | n++; | |
438 | if (dest[idx]==lastval) continue; | |
439 | ||
440 | //if lastval was 1, we have a 1->0 crossing | |
441 | if (dest[idx-1]==1) { | |
442 | if (!numBits && n < rfLen/fclow) { | |
443 | n=0; | |
444 | lastval = dest[idx]; | |
445 | continue; | |
446 | } | |
447 | n = (n * fclow + rfLen/2) / rfLen; | |
448 | } else {// 0->1 crossing | |
449 | //test first bitsample too small | |
450 | if (!numBits && n < rfLen/fchigh) { | |
451 | n=0; | |
452 | lastval = dest[idx]; | |
453 | continue; | |
454 | } | |
455 | n = (n * fchigh + rfLen/2) / rfLen; | |
456 | } | |
457 | if (n == 0) n = 1; | |
458 | ||
459 | memset(dest+numBits, dest[idx-1]^invert , n); | |
460 | numBits += n; | |
461 | n=0; | |
462 | lastval=dest[idx]; | |
463 | }//end for | |
464 | // if valid extra bits at the end were all the same frequency - add them in | |
465 | if (n > rfLen/fchigh) { | |
466 | if (dest[idx-2]==1) { | |
467 | n = (n * fclow + rfLen/2) / rfLen; | |
468 | } else { | |
469 | n = (n * fchigh + rfLen/2) / rfLen; | |
470 | } | |
471 | memset(dest+numBits, dest[idx-1]^invert , n); | |
472 | numBits += n; | |
473 | } | |
474 | return numBits; | |
475 | } | |
476 | //by marshmellow (from holiman's base) | |
477 | // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod) | |
478 | int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) | |
479 | { | |
480 | // FSK demodulator | |
481 | size = fsk_wave_demod(dest, size, fchigh, fclow); | |
482 | size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow); | |
483 | return size; | |
484 | } | |
485 | ||
486 | // loop to get raw HID waveform then FSK demodulate the TAG ID from it | |
487 | int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) | |
488 | { | |
489 | if (justNoise(dest, *size)) return -1; | |
490 | ||
491 | size_t numStart=0, size2=*size, startIdx=0; | |
492 | // FSK demodulator | |
493 | *size = fskdemod(dest, size2,50,1,10,8); //fsk2a | |
494 | if (*size < 96*2) return -2; | |
495 | // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 | |
496 | uint8_t preamble[] = {0,0,0,1,1,1,0,1}; | |
497 | // find bitstring in array | |
498 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
499 | if (errChk == 0) return -3; //preamble not found | |
500 | ||
501 | numStart = startIdx + sizeof(preamble); | |
502 | // final loop, go over previously decoded FSK data and manchester decode into usable tag ID | |
503 | for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ | |
504 | if (dest[idx] == dest[idx+1]){ | |
505 | return -4; //not manchester data | |
506 | } | |
507 | *hi2 = (*hi2<<1)|(*hi>>31); | |
508 | *hi = (*hi<<1)|(*lo>>31); | |
509 | //Then, shift in a 0 or one into low | |
510 | if (dest[idx] && !dest[idx+1]) // 1 0 | |
511 | *lo=(*lo<<1)|1; | |
512 | else // 0 1 | |
513 | *lo=(*lo<<1)|0; | |
514 | } | |
515 | return (int)startIdx; | |
516 | } | |
517 | ||
518 | // loop to get raw paradox waveform then FSK demodulate the TAG ID from it | |
519 | int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) | |
520 | { | |
521 | if (justNoise(dest, *size)) return -1; | |
522 | ||
523 | size_t numStart=0, size2=*size, startIdx=0; | |
524 | // FSK demodulator | |
525 | *size = fskdemod(dest, size2,50,1,10,8); //fsk2a | |
526 | if (*size < 96) return -2; | |
527 | ||
528 | // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 | |
529 | uint8_t preamble[] = {0,0,0,0,1,1,1,1}; | |
530 | ||
531 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
532 | if (errChk == 0) return -3; //preamble not found | |
533 | ||
534 | numStart = startIdx + sizeof(preamble); | |
535 | // final loop, go over previously decoded FSK data and manchester decode into usable tag ID | |
536 | for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ | |
537 | if (dest[idx] == dest[idx+1]) | |
538 | return -4; //not manchester data | |
539 | *hi2 = (*hi2<<1)|(*hi>>31); | |
540 | *hi = (*hi<<1)|(*lo>>31); | |
541 | //Then, shift in a 0 or one into low | |
542 | if (dest[idx] && !dest[idx+1]) // 1 0 | |
543 | *lo=(*lo<<1)|1; | |
544 | else // 0 1 | |
545 | *lo=(*lo<<1)|0; | |
546 | } | |
547 | return (int)startIdx; | |
548 | } | |
549 | ||
550 | uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) | |
551 | { | |
552 | uint32_t num = 0; | |
553 | for(int i = 0 ; i < numbits ; i++) | |
554 | { | |
555 | num = (num << 1) | (*src); | |
556 | src++; | |
557 | } | |
558 | return num; | |
559 | } | |
560 | ||
561 | //least significant bit first | |
562 | uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) | |
563 | { | |
564 | uint32_t num = 0; | |
565 | for(int i = 0 ; i < numbits ; i++) | |
566 | { | |
567 | num = (num << 1) | *(src + (numbits-(i+1))); | |
568 | } | |
569 | return num; | |
570 | } | |
571 | ||
572 | int IOdemodFSK(uint8_t *dest, size_t size) | |
573 | { | |
574 | if (justNoise(dest, size)) return -1; | |
575 | //make sure buffer has data | |
576 | if (size < 66*64) return -2; | |
577 | // FSK demodulator | |
578 | size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64 | |
579 | if (size < 65) return -3; //did we get a good demod? | |
580 | //Index map | |
581 | //0 10 20 30 40 50 60 | |
582 | //| | | | | | | | |
583 | //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23 | |
584 | //----------------------------------------------------------------------------- | |
585 | //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11 | |
586 | // | |
587 | //XSF(version)facility:codeone+codetwo | |
588 | //Handle the data | |
589 | size_t startIdx = 0; | |
590 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1}; | |
591 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx); | |
592 | if (errChk == 0) return -4; //preamble not found | |
593 | ||
594 | if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){ | |
595 | //confirmed proper separator bits found | |
596 | //return start position | |
597 | return (int) startIdx; | |
598 | } | |
599 | return -5; | |
600 | } | |
601 | ||
602 | // by marshmellow | |
603 | // takes a array of binary values, start position, length of bits per parity (includes parity bit), | |
604 | // Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run) | |
605 | size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) | |
606 | { | |
607 | uint32_t parityWd = 0; | |
608 | size_t j = 0, bitCnt = 0; | |
609 | for (int word = 0; word < (bLen); word+=pLen){ | |
610 | for (int bit=0; bit < pLen; bit++){ | |
611 | parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; | |
612 | BitStream[j++] = (BitStream[startIdx+word+bit]); | |
613 | } | |
614 | j--; // overwrite parity with next data | |
615 | // if parity fails then return 0 | |
616 | if (pType == 2) { // then marker bit which should be a 1 | |
617 | if (!BitStream[j]) return 0; | |
618 | } else { | |
619 | if (parityTest(parityWd, pLen, pType) == 0) return 0; | |
620 | } | |
621 | bitCnt+=(pLen-1); | |
622 | parityWd = 0; | |
623 | } | |
624 | // if we got here then all the parities passed | |
625 | //return ID start index and size | |
626 | return bitCnt; | |
627 | } | |
628 | ||
629 | // Ask/Biphase Demod then try to locate an ISO 11784/85 ID | |
630 | // BitStream must contain previously askrawdemod and biphasedemoded data | |
631 | int FDXBdemodBI(uint8_t *dest, size_t *size) | |
632 | { | |
633 | //make sure buffer has enough data | |
634 | if (*size < 128) return -1; | |
635 | ||
636 | size_t startIdx = 0; | |
637 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1}; | |
638 | ||
639 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
640 | if (errChk == 0) return -2; //preamble not found | |
641 | return (int)startIdx; | |
642 | } | |
643 | ||
644 | // by marshmellow | |
645 | // FSK Demod then try to locate an AWID ID | |
646 | int AWIDdemodFSK(uint8_t *dest, size_t *size) | |
647 | { | |
648 | //make sure buffer has enough data | |
649 | if (*size < 96*50) return -1; | |
650 | ||
651 | if (justNoise(dest, *size)) return -2; | |
652 | ||
653 | // FSK demodulator | |
654 | *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 | |
655 | if (*size < 96) return -3; //did we get a good demod? | |
656 | ||
657 | uint8_t preamble[] = {0,0,0,0,0,0,0,1}; | |
658 | size_t startIdx = 0; | |
659 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
660 | if (errChk == 0) return -4; //preamble not found | |
661 | if (*size != 96) return -5; | |
662 | return (int)startIdx; | |
663 | } | |
664 | ||
665 | // by marshmellow | |
666 | // FSK Demod then try to locate an Farpointe Data (pyramid) ID | |
667 | int PyramiddemodFSK(uint8_t *dest, size_t *size) | |
668 | { | |
669 | //make sure buffer has data | |
670 | if (*size < 128*50) return -5; | |
671 | ||
672 | //test samples are not just noise | |
673 | if (justNoise(dest, *size)) return -1; | |
674 | ||
675 | // FSK demodulator | |
676 | *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 | |
677 | if (*size < 128) return -2; //did we get a good demod? | |
678 | ||
679 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}; | |
680 | size_t startIdx = 0; | |
681 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
682 | if (errChk == 0) return -4; //preamble not found | |
683 | if (*size != 128) return -3; | |
684 | return (int)startIdx; | |
685 | } | |
686 | ||
687 | // by marshmellow | |
688 | // to detect a wave that has heavily clipped (clean) samples | |
689 | uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) | |
690 | { | |
691 | uint16_t allPeaks=1; | |
692 | uint16_t cntPeaks=0; | |
693 | size_t loopEnd = 512+60; | |
694 | if (loopEnd > size) loopEnd = size; | |
695 | for (size_t i=60; i<loopEnd; i++){ | |
696 | if (dest[i]>low && dest[i]<high) | |
697 | allPeaks=0; | |
698 | else | |
699 | cntPeaks++; | |
700 | } | |
701 | if (allPeaks == 0){ | |
702 | if (cntPeaks > 300) return 1; | |
703 | } | |
704 | return allPeaks; | |
705 | } | |
706 | ||
707 | // by marshmellow | |
708 | // to help detect clocks on heavily clipped samples | |
709 | // based on count of low to low | |
710 | int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low) | |
711 | { | |
712 | uint8_t fndClk[] = {8,16,32,40,50,64,128}; | |
713 | size_t startwave; | |
714 | size_t i = 0; | |
715 | size_t minClk = 255; | |
716 | // get to first full low to prime loop and skip incomplete first pulse | |
717 | while ((dest[i] < high) && (i < size)) | |
718 | ++i; | |
719 | while ((dest[i] > low) && (i < size)) | |
720 | ++i; | |
721 | ||
722 | // loop through all samples | |
723 | while (i < size) { | |
724 | // measure from low to low | |
725 | while ((dest[i] > low) && (i < size)) | |
726 | ++i; | |
727 | startwave= i; | |
728 | while ((dest[i] < high) && (i < size)) | |
729 | ++i; | |
730 | while ((dest[i] > low) && (i < size)) | |
731 | ++i; | |
732 | //get minimum measured distance | |
733 | if (i-startwave < minClk && i < size) | |
734 | minClk = i - startwave; | |
735 | } | |
736 | // set clock | |
737 | for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { | |
738 | if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) | |
739 | return fndClk[clkCnt]; | |
740 | } | |
741 | return 0; | |
742 | } | |
743 | ||
744 | // by marshmellow | |
745 | // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping) | |
746 | // maybe somehow adjust peak trimming value based on samples to fix? | |
747 | // return start index of best starting position for that clock and return clock (by reference) | |
748 | int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) | |
749 | { | |
750 | size_t i=1; | |
751 | uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255}; | |
752 | uint8_t clkEnd = 9; | |
753 | uint8_t loopCnt = 255; //don't need to loop through entire array... | |
754 | if (size <= loopCnt) return -1; //not enough samples | |
755 | ||
756 | //if we already have a valid clock | |
757 | uint8_t clockFnd=0; | |
758 | for (;i<clkEnd;++i) | |
759 | if (clk[i] == *clock) clockFnd = i; | |
760 | //clock found but continue to find best startpos | |
761 | ||
762 | //get high and low peak | |
763 | int peak, low; | |
764 | if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1; | |
765 | ||
766 | //test for large clean peaks | |
767 | if (!clockFnd){ | |
768 | if (DetectCleanAskWave(dest, size, peak, low)==1){ | |
769 | int ans = DetectStrongAskClock(dest, size, peak, low); | |
770 | for (i=clkEnd-1; i>0; i--){ | |
771 | if (clk[i] == ans) { | |
772 | *clock = ans; | |
773 | //clockFnd = i; | |
774 | return 0; // for strong waves i don't use the 'best start position' yet... | |
775 | //break; //clock found but continue to find best startpos [not yet] | |
776 | } | |
777 | } | |
778 | } | |
779 | } | |
780 | ||
781 | uint8_t ii; | |
782 | uint8_t clkCnt, tol = 0; | |
783 | uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; | |
784 | uint8_t bestStart[]={0,0,0,0,0,0,0,0,0}; | |
785 | size_t errCnt = 0; | |
786 | size_t arrLoc, loopEnd; | |
787 | ||
788 | if (clockFnd>0) { | |
789 | clkCnt = clockFnd; | |
790 | clkEnd = clockFnd+1; | |
791 | } | |
792 | else clkCnt=1; | |
793 | ||
794 | //test each valid clock from smallest to greatest to see which lines up | |
795 | for(; clkCnt < clkEnd; clkCnt++){ | |
796 | if (clk[clkCnt] <= 32){ | |
797 | tol=1; | |
798 | }else{ | |
799 | tol=0; | |
800 | } | |
801 | //if no errors allowed - keep start within the first clock | |
802 | if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2; | |
803 | bestErr[clkCnt]=1000; | |
804 | //try lining up the peaks by moving starting point (try first few clocks) | |
805 | for (ii=0; ii < loopCnt; ii++){ | |
806 | if (dest[ii] < peak && dest[ii] > low) continue; | |
807 | ||
808 | errCnt=0; | |
809 | // now that we have the first one lined up test rest of wave array | |
810 | loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1; | |
811 | for (i=0; i < loopEnd; ++i){ | |
812 | arrLoc = ii + (i * clk[clkCnt]); | |
813 | if (dest[arrLoc] >= peak || dest[arrLoc] <= low){ | |
814 | }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){ | |
815 | }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){ | |
816 | }else{ //error no peak detected | |
817 | errCnt++; | |
818 | } | |
819 | } | |
820 | //if we found no errors then we can stop here and a low clock (common clocks) | |
821 | // this is correct one - return this clock | |
822 | //PrintAndLog("DEBUG: clk %d, err %d, ii %d, i %d",clk[clkCnt],errCnt,ii,i); | |
823 | if(errCnt==0 && clkCnt<7) { | |
824 | if (!clockFnd) *clock = clk[clkCnt]; | |
825 | return ii; | |
826 | } | |
827 | //if we found errors see if it is lowest so far and save it as best run | |
828 | if(errCnt<bestErr[clkCnt]){ | |
829 | bestErr[clkCnt]=errCnt; | |
830 | bestStart[clkCnt]=ii; | |
831 | } | |
832 | } | |
833 | } | |
834 | uint8_t iii; | |
835 | uint8_t best=0; | |
836 | for (iii=1; iii<clkEnd; ++iii){ | |
837 | if (bestErr[iii] < bestErr[best]){ | |
838 | if (bestErr[iii] == 0) bestErr[iii]=1; | |
839 | // current best bit to error ratio vs new bit to error ratio | |
840 | if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){ | |
841 | best = iii; | |
842 | } | |
843 | } | |
844 | } | |
845 | //if (bestErr[best] > maxErr) return -1; | |
846 | if (!clockFnd) *clock = clk[best]; | |
847 | return bestStart[best]; | |
848 | } | |
849 | ||
850 | //by marshmellow | |
851 | //detect psk clock by reading each phase shift | |
852 | // a phase shift is determined by measuring the sample length of each wave | |
853 | int DetectPSKClock(uint8_t dest[], size_t size, int clock) | |
854 | { | |
855 | uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock | |
856 | uint16_t loopCnt = 4096; //don't need to loop through entire array... | |
857 | if (size == 0) return 0; | |
858 | if (size<loopCnt) loopCnt = size; | |
859 | ||
860 | //if we already have a valid clock quit | |
861 | size_t i=1; | |
862 | for (; i < 8; ++i) | |
863 | if (clk[i] == clock) return clock; | |
864 | ||
865 | size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0; | |
866 | uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1; | |
867 | uint16_t peakcnt=0, errCnt=0, waveLenCnt=0; | |
868 | uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; | |
869 | uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0}; | |
870 | fc = countFC(dest, size, 0); | |
871 | if (fc!=2 && fc!=4 && fc!=8) return -1; | |
872 | //PrintAndLog("DEBUG: FC: %d",fc); | |
873 | ||
874 | //find first full wave | |
875 | for (i=0; i<loopCnt; i++){ | |
876 | if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
877 | if (waveStart == 0) { | |
878 | waveStart = i+1; | |
879 | //PrintAndLog("DEBUG: waveStart: %d",waveStart); | |
880 | } else { | |
881 | waveEnd = i+1; | |
882 | //PrintAndLog("DEBUG: waveEnd: %d",waveEnd); | |
883 | waveLenCnt = waveEnd-waveStart; | |
884 | if (waveLenCnt > fc){ | |
885 | firstFullWave = waveStart; | |
886 | fullWaveLen=waveLenCnt; | |
887 | break; | |
888 | } | |
889 | waveStart=0; | |
890 | } | |
891 | } | |
892 | } | |
893 | //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen); | |
894 | ||
895 | //test each valid clock from greatest to smallest to see which lines up | |
896 | for(clkCnt=7; clkCnt >= 1 ; clkCnt--){ | |
897 | lastClkBit = firstFullWave; //set end of wave as clock align | |
898 | waveStart = 0; | |
899 | errCnt=0; | |
900 | peakcnt=0; | |
901 | //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit); | |
902 | ||
903 | for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){ | |
904 | //top edge of wave = start of new wave | |
905 | if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
906 | if (waveStart == 0) { | |
907 | waveStart = i+1; | |
908 | waveLenCnt=0; | |
909 | } else { //waveEnd | |
910 | waveEnd = i+1; | |
911 | waveLenCnt = waveEnd-waveStart; | |
912 | if (waveLenCnt > fc){ | |
913 | //if this wave is a phase shift | |
914 | //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, ii: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,ii+1,fc); | |
915 | if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit | |
916 | peakcnt++; | |
917 | lastClkBit+=clk[clkCnt]; | |
918 | } else if (i<lastClkBit+8){ | |
919 | //noise after a phase shift - ignore | |
920 | } else { //phase shift before supposed to based on clock | |
921 | errCnt++; | |
922 | } | |
923 | } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){ | |
924 | lastClkBit+=clk[clkCnt]; //no phase shift but clock bit | |
925 | } | |
926 | waveStart=i+1; | |
927 | } | |
928 | } | |
929 | } | |
930 | if (errCnt == 0){ | |
931 | return clk[clkCnt]; | |
932 | } | |
933 | if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt; | |
934 | if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt; | |
935 | } | |
936 | //all tested with errors | |
937 | //return the highest clk with the most peaks found | |
938 | uint8_t best=7; | |
939 | for (i=7; i>=1; i--){ | |
940 | if (peaksdet[i] > peaksdet[best]) { | |
941 | best = i; | |
942 | } | |
943 | //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]); | |
944 | } | |
945 | return clk[best]; | |
946 | } | |
947 | ||
948 | //by marshmellow | |
949 | //detect nrz clock by reading #peaks vs no peaks(or errors) | |
950 | int DetectNRZClock(uint8_t dest[], size_t size, int clock) | |
951 | { | |
952 | size_t i=0; | |
953 | uint8_t clk[]={8,16,32,40,50,64,100,128,255}; | |
954 | size_t loopCnt = 4096; //don't need to loop through entire array... | |
955 | if (size == 0) return 0; | |
956 | if (size<loopCnt) loopCnt = size; | |
957 | ||
958 | //if we already have a valid clock quit | |
959 | for (; i < 8; ++i) | |
960 | if (clk[i] == clock) return clock; | |
961 | ||
962 | //get high and low peak | |
963 | int peak, low; | |
964 | if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0; | |
965 | ||
966 | //PrintAndLog("DEBUG: peak: %d, low: %d",peak,low); | |
967 | size_t ii; | |
968 | uint8_t clkCnt; | |
969 | uint8_t tol = 0; | |
970 | uint16_t peakcnt=0; | |
971 | uint16_t peaksdet[]={0,0,0,0,0,0,0,0}; | |
972 | uint16_t maxPeak=0; | |
973 | //test for large clipped waves | |
974 | for (i=0; i<loopCnt; i++){ | |
975 | if (dest[i] >= peak || dest[i] <= low){ | |
976 | peakcnt++; | |
977 | } else { | |
978 | if (peakcnt>0 && maxPeak < peakcnt){ | |
979 | maxPeak = peakcnt; | |
980 | } | |
981 | peakcnt=0; | |
982 | } | |
983 | } | |
984 | peakcnt=0; | |
985 | //test each valid clock from smallest to greatest to see which lines up | |
986 | for(clkCnt=0; clkCnt < 8; ++clkCnt){ | |
987 | //ignore clocks smaller than largest peak | |
988 | if (clk[clkCnt]<maxPeak) continue; | |
989 | ||
990 | //try lining up the peaks by moving starting point (try first 256) | |
991 | for (ii=0; ii< loopCnt; ++ii){ | |
992 | if ((dest[ii] >= peak) || (dest[ii] <= low)){ | |
993 | peakcnt=0; | |
994 | // now that we have the first one lined up test rest of wave array | |
995 | for (i=0; i < ((int)((size-ii-tol)/clk[clkCnt])-1); ++i){ | |
996 | if (dest[ii+(i*clk[clkCnt])]>=peak || dest[ii+(i*clk[clkCnt])]<=low){ | |
997 | peakcnt++; | |
998 | } | |
999 | } | |
1000 | if(peakcnt>peaksdet[clkCnt]) { | |
1001 | peaksdet[clkCnt]=peakcnt; | |
1002 | } | |
1003 | } | |
1004 | } | |
1005 | } | |
1006 | int iii=7; | |
1007 | uint8_t best=0; | |
1008 | for (iii=7; iii > 0; iii--){ | |
1009 | if (peaksdet[iii] > peaksdet[best]){ | |
1010 | best = iii; | |
1011 | } | |
1012 | //PrintAndLog("DEBUG: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[iii],peaksdet[iii],bestErr[iii],clk[best]); | |
1013 | } | |
1014 | return clk[best]; | |
1015 | } | |
1016 | ||
1017 | // by marshmellow | |
1018 | // convert psk1 demod to psk2 demod | |
1019 | // only transition waves are 1s | |
1020 | void psk1TOpsk2(uint8_t *BitStream, size_t size) | |
1021 | { | |
1022 | size_t i=1; | |
1023 | uint8_t lastBit=BitStream[0]; | |
1024 | for (; i<size; i++){ | |
1025 | if (BitStream[i]==7){ | |
1026 | //ignore errors | |
1027 | } else if (lastBit!=BitStream[i]){ | |
1028 | lastBit=BitStream[i]; | |
1029 | BitStream[i]=1; | |
1030 | } else { | |
1031 | BitStream[i]=0; | |
1032 | } | |
1033 | } | |
1034 | return; | |
1035 | } | |
1036 | ||
1037 | // by marshmellow | |
1038 | // convert psk2 demod to psk1 demod | |
1039 | // from only transition waves are 1s to phase shifts change bit | |
1040 | void psk2TOpsk1(uint8_t *BitStream, size_t size) | |
1041 | { | |
1042 | uint8_t phase=0; | |
1043 | for (size_t i=0; i<size; i++){ | |
1044 | if (BitStream[i]==1){ | |
1045 | phase ^=1; | |
1046 | } | |
1047 | BitStream[i]=phase; | |
1048 | } | |
1049 | return; | |
1050 | } | |
1051 | ||
1052 | // redesigned by marshmellow adjusted from existing decode functions | |
1053 | // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more | |
1054 | int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) | |
1055 | { | |
1056 | //26 bit 40134 format (don't know other formats) | |
1057 | int i; | |
1058 | int long_wait=29;//29 leading zeros in format | |
1059 | int start; | |
1060 | int first = 0; | |
1061 | int first2 = 0; | |
1062 | int bitCnt = 0; | |
1063 | int ii; | |
1064 | // Finding the start of a UID | |
1065 | for (start = 0; start <= *size - 250; start++) { | |
1066 | first = bitStream[start]; | |
1067 | for (i = start; i < start + long_wait; i++) { | |
1068 | if (bitStream[i] != first) { | |
1069 | break; | |
1070 | } | |
1071 | } | |
1072 | if (i == (start + long_wait)) { | |
1073 | break; | |
1074 | } | |
1075 | } | |
1076 | if (start == *size - 250 + 1) { | |
1077 | // did not find start sequence | |
1078 | return -1; | |
1079 | } | |
1080 | // Inverting signal if needed | |
1081 | if (first == 1) { | |
1082 | for (i = start; i < *size; i++) { | |
1083 | bitStream[i] = !bitStream[i]; | |
1084 | } | |
1085 | *invert = 1; | |
1086 | }else *invert=0; | |
1087 | ||
1088 | int iii; | |
1089 | //found start once now test length by finding next one | |
1090 | for (ii=start+29; ii <= *size - 250; ii++) { | |
1091 | first2 = bitStream[ii]; | |
1092 | for (iii = ii; iii < ii + long_wait; iii++) { | |
1093 | if (bitStream[iii] != first2) { | |
1094 | break; | |
1095 | } | |
1096 | } | |
1097 | if (iii == (ii + long_wait)) { | |
1098 | break; | |
1099 | } | |
1100 | } | |
1101 | if (ii== *size - 250 + 1){ | |
1102 | // did not find second start sequence | |
1103 | return -2; | |
1104 | } | |
1105 | bitCnt=ii-start; | |
1106 | ||
1107 | // Dumping UID | |
1108 | i = start; | |
1109 | for (ii = 0; ii < bitCnt; ii++) { | |
1110 | bitStream[ii] = bitStream[i++]; | |
1111 | } | |
1112 | *size=bitCnt; | |
1113 | return 1; | |
1114 | } | |
1115 | ||
1116 | // by marshmellow - demodulate NRZ wave (both similar enough) | |
1117 | // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak | |
1118 | // there probably is a much simpler way to do this.... | |
1119 | int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert, int maxErr) | |
1120 | { | |
1121 | if (justNoise(dest, *size)) return -1; | |
1122 | *clk = DetectNRZClock(dest, *size, *clk); | |
1123 | if (*clk==0) return -2; | |
1124 | size_t i, gLen = 4096; | |
1125 | if (gLen>*size) gLen = *size; | |
1126 | int high, low; | |
1127 | if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low | |
1128 | int lastBit = 0; //set first clock check | |
1129 | size_t iii = 0, bitnum = 0; //bitnum counter | |
1130 | uint16_t errCnt = 0, MaxBits = 1000; | |
1131 | size_t bestErrCnt = maxErr+1; | |
1132 | size_t bestPeakCnt = 0, bestPeakStart = 0; | |
1133 | uint8_t bestFirstPeakHigh=0, firstPeakHigh=0, curBit=0, bitHigh=0, errBitHigh=0; | |
1134 | uint8_t tol = 1; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave | |
1135 | uint16_t peakCnt=0; | |
1136 | uint8_t ignoreWindow=4; | |
1137 | uint8_t ignoreCnt=ignoreWindow; //in case of noise near peak | |
1138 | //loop to find first wave that works - align to clock | |
1139 | for (iii=0; iii < gLen; ++iii){ | |
1140 | if ((dest[iii]>=high) || (dest[iii]<=low)){ | |
1141 | if (dest[iii]>=high) firstPeakHigh=1; | |
1142 | else firstPeakHigh=0; | |
1143 | lastBit=iii-*clk; | |
1144 | peakCnt=0; | |
1145 | errCnt=0; | |
1146 | //loop through to see if this start location works | |
1147 | for (i = iii; i < *size; ++i) { | |
1148 | // if we are at a clock bit | |
1149 | if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) { | |
1150 | //test high/low | |
1151 | if (dest[i] >= high || dest[i] <= low) { | |
1152 | bitHigh = 1; | |
1153 | peakCnt++; | |
1154 | errBitHigh = 0; | |
1155 | ignoreCnt = ignoreWindow; | |
1156 | lastBit += *clk; | |
1157 | } else if (i == lastBit + *clk + tol) { | |
1158 | lastBit += *clk; | |
1159 | } | |
1160 | //else if no bars found | |
1161 | } else if (dest[i] < high && dest[i] > low){ | |
1162 | if (ignoreCnt==0){ | |
1163 | bitHigh=0; | |
1164 | if (errBitHigh==1) errCnt++; | |
1165 | errBitHigh=0; | |
1166 | } else { | |
1167 | ignoreCnt--; | |
1168 | } | |
1169 | } else if ((dest[i]>=high || dest[i]<=low) && (bitHigh==0)) { | |
1170 | //error bar found no clock... | |
1171 | errBitHigh=1; | |
1172 | } | |
1173 | if (((i-iii) / *clk)>=MaxBits) break; | |
1174 | } | |
1175 | //we got more than 64 good bits and not all errors | |
1176 | if (((i-iii) / *clk) > 64 && (errCnt <= (maxErr))) { | |
1177 | //possible good read | |
1178 | if (!errCnt || peakCnt > bestPeakCnt){ | |
1179 | bestFirstPeakHigh=firstPeakHigh; | |
1180 | bestErrCnt = errCnt; | |
1181 | bestPeakCnt = peakCnt; | |
1182 | bestPeakStart = iii; | |
1183 | if (!errCnt) break; //great read - finish | |
1184 | } | |
1185 | } | |
1186 | } | |
1187 | } | |
1188 | //PrintAndLog("DEBUG: bestErrCnt: %d, maxErr: %d, bestStart: %d, bestPeakCnt: %d, bestPeakStart: %d",bestErrCnt,maxErr,bestStart,bestPeakCnt,bestPeakStart); | |
1189 | if (bestErrCnt > maxErr) return bestErrCnt; | |
1190 | ||
1191 | //best run is good enough set to best run and set overwrite BinStream | |
1192 | lastBit = bestPeakStart - *clk; | |
1193 | memset(dest, bestFirstPeakHigh^1, bestPeakStart / *clk); | |
1194 | bitnum += (bestPeakStart / *clk); | |
1195 | for (i = bestPeakStart; i < *size; ++i) { | |
1196 | // if expecting a clock bit | |
1197 | if ((i >= lastBit + *clk - tol) && (i <= lastBit + *clk + tol)) { | |
1198 | // test high/low | |
1199 | if (dest[i] >= high || dest[i] <= low) { | |
1200 | peakCnt++; | |
1201 | bitHigh = 1; | |
1202 | errBitHigh = 0; | |
1203 | ignoreCnt = ignoreWindow; | |
1204 | curBit = *invert; | |
1205 | if (dest[i] >= high) curBit ^= 1; | |
1206 | dest[bitnum++] = curBit; | |
1207 | lastBit += *clk; | |
1208 | //else no bars found in clock area | |
1209 | } else if (i == lastBit + *clk + tol) { | |
1210 | dest[bitnum++] = curBit; | |
1211 | lastBit += *clk; | |
1212 | } | |
1213 | //else if no bars found | |
1214 | } else if (dest[i] < high && dest[i] > low){ | |
1215 | if (ignoreCnt == 0){ | |
1216 | bitHigh = 0; | |
1217 | if (errBitHigh == 1){ | |
1218 | dest[bitnum++] = 7; | |
1219 | errCnt++; | |
1220 | } | |
1221 | errBitHigh=0; | |
1222 | } else { | |
1223 | ignoreCnt--; | |
1224 | } | |
1225 | } else if ((dest[i] >= high || dest[i] <= low) && (bitHigh == 0)) { | |
1226 | //error bar found no clock... | |
1227 | errBitHigh=1; | |
1228 | } | |
1229 | if (bitnum >= MaxBits) break; | |
1230 | } | |
1231 | *size = bitnum; | |
1232 | return bestErrCnt; | |
1233 | } | |
1234 | ||
1235 | //by marshmellow | |
1236 | //detects the bit clock for FSK given the high and low Field Clocks | |
1237 | uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) | |
1238 | { | |
1239 | uint8_t clk[] = {8,16,32,40,50,64,100,128,0}; | |
1240 | uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1241 | uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1242 | uint8_t rfLensFnd = 0; | |
1243 | uint8_t lastFCcnt = 0; | |
1244 | uint16_t fcCounter = 0; | |
1245 | uint16_t rfCounter = 0; | |
1246 | uint8_t firstBitFnd = 0; | |
1247 | size_t i; | |
1248 | if (size == 0) return 0; | |
1249 | ||
1250 | uint8_t fcTol = (uint8_t)(0.5+(float)(fcHigh-fcLow)/2); | |
1251 | rfLensFnd=0; | |
1252 | fcCounter=0; | |
1253 | rfCounter=0; | |
1254 | firstBitFnd=0; | |
1255 | //PrintAndLog("DEBUG: fcTol: %d",fcTol); | |
1256 | // prime i to first up transition | |
1257 | for (i = 1; i < size-1; i++) | |
1258 | if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]) | |
1259 | break; | |
1260 | ||
1261 | for (; i < size-1; i++){ | |
1262 | fcCounter++; | |
1263 | rfCounter++; | |
1264 | ||
1265 | if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1]) | |
1266 | continue; | |
1267 | // else new peak | |
1268 | // if we got less than the small fc + tolerance then set it to the small fc | |
1269 | if (fcCounter < fcLow+fcTol) | |
1270 | fcCounter = fcLow; | |
1271 | else //set it to the large fc | |
1272 | fcCounter = fcHigh; | |
1273 | ||
1274 | //look for bit clock (rf/xx) | |
1275 | if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){ | |
1276 | //not the same size as the last wave - start of new bit sequence | |
1277 | if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit | |
1278 | for (int ii=0; ii<15; ii++){ | |
1279 | if (rfLens[ii] == rfCounter){ | |
1280 | rfCnts[ii]++; | |
1281 | rfCounter = 0; | |
1282 | break; | |
1283 | } | |
1284 | } | |
1285 | if (rfCounter > 0 && rfLensFnd < 15){ | |
1286 | //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter); | |
1287 | rfCnts[rfLensFnd]++; | |
1288 | rfLens[rfLensFnd++] = rfCounter; | |
1289 | } | |
1290 | } else { | |
1291 | firstBitFnd++; | |
1292 | } | |
1293 | rfCounter=0; | |
1294 | lastFCcnt=fcCounter; | |
1295 | } | |
1296 | fcCounter=0; | |
1297 | } | |
1298 | uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15; | |
1299 | ||
1300 | for (i=0; i<15; i++){ | |
1301 | //PrintAndLog("DEBUG: RF %d, cnts %d",rfLens[i], rfCnts[i]); | |
1302 | //get highest 2 RF values (might need to get more values to compare or compare all?) | |
1303 | if (rfCnts[i]>rfCnts[rfHighest]){ | |
1304 | rfHighest3=rfHighest2; | |
1305 | rfHighest2=rfHighest; | |
1306 | rfHighest=i; | |
1307 | } else if(rfCnts[i]>rfCnts[rfHighest2]){ | |
1308 | rfHighest3=rfHighest2; | |
1309 | rfHighest2=i; | |
1310 | } else if(rfCnts[i]>rfCnts[rfHighest3]){ | |
1311 | rfHighest3=i; | |
1312 | } | |
1313 | } | |
1314 | // set allowed clock remainder tolerance to be 1 large field clock length+1 | |
1315 | // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off | |
1316 | uint8_t tol1 = fcHigh+1; | |
1317 | ||
1318 | //PrintAndLog("DEBUG: hightest: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]); | |
1319 | ||
1320 | // loop to find the highest clock that has a remainder less than the tolerance | |
1321 | // compare samples counted divided by | |
1322 | int ii=7; | |
1323 | for (; ii>=0; ii--){ | |
1324 | if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){ | |
1325 | if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){ | |
1326 | if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){ | |
1327 | break; | |
1328 | } | |
1329 | } | |
1330 | } | |
1331 | } | |
1332 | ||
1333 | if (ii<0) return 0; // oops we went too far | |
1334 | ||
1335 | return clk[ii]; | |
1336 | } | |
1337 | ||
1338 | //by marshmellow | |
1339 | //countFC is to detect the field clock lengths. | |
1340 | //counts and returns the 2 most common wave lengths | |
1341 | //mainly used for FSK field clock detection | |
1342 | uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) | |
1343 | { | |
1344 | uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0}; | |
1345 | uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0}; | |
1346 | uint8_t fcLensFnd = 0; | |
1347 | uint8_t lastFCcnt=0; | |
1348 | uint8_t fcCounter = 0; | |
1349 | size_t i; | |
1350 | if (size == 0) return 0; | |
1351 | ||
1352 | // prime i to first up transition | |
1353 | for (i = 1; i < size-1; i++) | |
1354 | if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]) | |
1355 | break; | |
1356 | ||
1357 | for (; i < size-1; i++){ | |
1358 | if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){ | |
1359 | // new up transition | |
1360 | fcCounter++; | |
1361 | if (fskAdj){ | |
1362 | //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8) | |
1363 | if (lastFCcnt==5 && fcCounter==9) fcCounter--; | |
1364 | //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5) | |
1365 | if ((fcCounter==9) || fcCounter==4) fcCounter++; | |
1366 | // save last field clock count (fc/xx) | |
1367 | lastFCcnt = fcCounter; | |
1368 | } | |
1369 | // find which fcLens to save it to: | |
1370 | for (int ii=0; ii<10; ii++){ | |
1371 | if (fcLens[ii]==fcCounter){ | |
1372 | fcCnts[ii]++; | |
1373 | fcCounter=0; | |
1374 | break; | |
1375 | } | |
1376 | } | |
1377 | if (fcCounter>0 && fcLensFnd<10){ | |
1378 | //add new fc length | |
1379 | fcCnts[fcLensFnd]++; | |
1380 | fcLens[fcLensFnd++]=fcCounter; | |
1381 | } | |
1382 | fcCounter=0; | |
1383 | } else { | |
1384 | // count sample | |
1385 | fcCounter++; | |
1386 | } | |
1387 | } | |
1388 | ||
1389 | uint8_t best1=9, best2=9, best3=9; | |
1390 | uint16_t maxCnt1=0; | |
1391 | // go through fclens and find which ones are bigest 2 | |
1392 | for (i=0; i<10; i++){ | |
1393 | // PrintAndLog("DEBUG: FC %d, Cnt %d, Errs %d",fcLens[i],fcCnts[i],errCnt); | |
1394 | // get the 3 best FC values | |
1395 | if (fcCnts[i]>maxCnt1) { | |
1396 | best3=best2; | |
1397 | best2=best1; | |
1398 | maxCnt1=fcCnts[i]; | |
1399 | best1=i; | |
1400 | } else if(fcCnts[i]>fcCnts[best2]){ | |
1401 | best3=best2; | |
1402 | best2=i; | |
1403 | } else if(fcCnts[i]>fcCnts[best3]){ | |
1404 | best3=i; | |
1405 | } | |
1406 | } | |
1407 | uint8_t fcH=0, fcL=0; | |
1408 | if (fcLens[best1]>fcLens[best2]){ | |
1409 | fcH=fcLens[best1]; | |
1410 | fcL=fcLens[best2]; | |
1411 | } else{ | |
1412 | fcH=fcLens[best2]; | |
1413 | fcL=fcLens[best1]; | |
1414 | } | |
1415 | ||
1416 | // TODO: take top 3 answers and compare to known Field clocks to get top 2 | |
1417 | ||
1418 | uint16_t fcs = (((uint16_t)fcH)<<8) | fcL; | |
1419 | // PrintAndLog("DEBUG: Best %d best2 %d best3 %d",fcLens[best1],fcLens[best2],fcLens[best3]); | |
1420 | if (fskAdj) return fcs; | |
1421 | return fcLens[best1]; | |
1422 | } | |
1423 | ||
1424 | //by marshmellow - demodulate PSK1 wave | |
1425 | //uses wave lengths (# Samples) | |
1426 | int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) | |
1427 | { | |
1428 | if (size == 0) return -1; | |
1429 | uint16_t loopCnt = 4096; //don't need to loop through entire array... | |
1430 | if (*size<loopCnt) loopCnt = *size; | |
1431 | ||
1432 | uint8_t curPhase = *invert; | |
1433 | size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0; | |
1434 | uint8_t fc=0, fullWaveLen=0, tol=1; | |
1435 | uint16_t errCnt=0, waveLenCnt=0; | |
1436 | fc = countFC(dest, *size, 0); | |
1437 | if (fc!=2 && fc!=4 && fc!=8) return -1; | |
1438 | //PrintAndLog("DEBUG: FC: %d",fc); | |
1439 | *clock = DetectPSKClock(dest, *size, *clock); | |
1440 | if (*clock == 0) return -1; | |
1441 | int avgWaveVal=0, lastAvgWaveVal=0; | |
1442 | //find first phase shift | |
1443 | for (i=0; i<loopCnt; i++){ | |
1444 | if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1445 | waveEnd = i+1; | |
1446 | //PrintAndLog("DEBUG: waveEnd: %d",waveEnd); | |
1447 | waveLenCnt = waveEnd-waveStart; | |
1448 | if (waveLenCnt > fc && waveStart > fc){ //not first peak and is a large wave | |
1449 | lastAvgWaveVal = avgWaveVal/(waveLenCnt); | |
1450 | firstFullWave = waveStart; | |
1451 | fullWaveLen=waveLenCnt; | |
1452 | //if average wave value is > graph 0 then it is an up wave or a 1 | |
1453 | if (lastAvgWaveVal > 123) curPhase ^= 1; //fudge graph 0 a little 123 vs 128 | |
1454 | break; | |
1455 | } | |
1456 | waveStart = i+1; | |
1457 | avgWaveVal = 0; | |
1458 | } | |
1459 | avgWaveVal += dest[i+2]; | |
1460 | } | |
1461 | //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen); | |
1462 | lastClkBit = firstFullWave; //set start of wave as clock align | |
1463 | //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit); | |
1464 | waveStart = 0; | |
1465 | size_t numBits=0; | |
1466 | //set skipped bits | |
1467 | memset(dest, curPhase^1, firstFullWave / *clock); | |
1468 | numBits += (firstFullWave / *clock); | |
1469 | dest[numBits++] = curPhase; //set first read bit | |
1470 | for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){ | |
1471 | //top edge of wave = start of new wave | |
1472 | if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1473 | if (waveStart == 0) { | |
1474 | waveStart = i+1; | |
1475 | waveLenCnt = 0; | |
1476 | avgWaveVal = dest[i+1]; | |
1477 | } else { //waveEnd | |
1478 | waveEnd = i+1; | |
1479 | waveLenCnt = waveEnd-waveStart; | |
1480 | lastAvgWaveVal = avgWaveVal/waveLenCnt; | |
1481 | if (waveLenCnt > fc){ | |
1482 | //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal); | |
1483 | //this wave is a phase shift | |
1484 | //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc); | |
1485 | if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit | |
1486 | curPhase ^= 1; | |
1487 | dest[numBits++] = curPhase; | |
1488 | lastClkBit += *clock; | |
1489 | } else if (i < lastClkBit+10+fc){ | |
1490 | //noise after a phase shift - ignore | |
1491 | } else { //phase shift before supposed to based on clock | |
1492 | errCnt++; | |
1493 | dest[numBits++] = 7; | |
1494 | } | |
1495 | } else if (i+1 > lastClkBit + *clock + tol + fc){ | |
1496 | lastClkBit += *clock; //no phase shift but clock bit | |
1497 | dest[numBits++] = curPhase; | |
1498 | } | |
1499 | avgWaveVal = 0; | |
1500 | waveStart = i+1; | |
1501 | } | |
1502 | } | |
1503 | avgWaveVal += dest[i+1]; | |
1504 | } | |
1505 | *size = numBits; | |
1506 | return errCnt; | |
1507 | } |