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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 "lfdemod.h" | |
13 | #include <string.h> | |
14 | ||
15 | //to allow debug print calls when used not on device | |
16 | void dummy(char *fmt, ...){} | |
17 | ||
18 | #ifndef ON_DEVICE | |
19 | #include "ui.h" | |
20 | #include "cmdparser.h" | |
21 | #include "cmddata.h" | |
22 | #define prnt PrintAndLog | |
23 | #else | |
24 | uint8_t g_debugMode=0; | |
25 | #define prnt dummy | |
26 | #endif | |
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 | if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits); | |
66 | return (ans == pType); | |
67 | } | |
68 | ||
69 | // by marshmellow | |
70 | // takes a array of binary values, start position, length of bits per parity (includes parity bit), | |
71 | // Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run) | |
72 | size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen) | |
73 | { | |
74 | uint32_t parityWd = 0; | |
75 | size_t j = 0, bitCnt = 0; | |
76 | for (int word = 0; word < (bLen); word+=pLen) { | |
77 | for (int bit=0; bit < pLen; bit++) { | |
78 | parityWd = (parityWd << 1) | BitStream[startIdx+word+bit]; | |
79 | BitStream[j++] = (BitStream[startIdx+word+bit]); | |
80 | } | |
81 | if (word+pLen > bLen) break; | |
82 | ||
83 | j--; // overwrite parity with next data | |
84 | // if parity fails then return 0 | |
85 | switch (pType) { | |
86 | case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit | |
87 | case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit | |
88 | default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity | |
89 | } | |
90 | bitCnt+=(pLen-1); | |
91 | parityWd = 0; | |
92 | } | |
93 | // if we got here then all the parities passed | |
94 | //return ID start index and size | |
95 | return bitCnt; | |
96 | } | |
97 | ||
98 | // by marshmellow | |
99 | // takes a array of binary values, length of bits per parity (includes parity bit), | |
100 | // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run) | |
101 | // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added | |
102 | size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType) | |
103 | { | |
104 | uint32_t parityWd = 0; | |
105 | size_t j = 0, bitCnt = 0; | |
106 | for (int word = 0; word < sourceLen; word+=pLen-1) { | |
107 | for (int bit=0; bit < pLen-1; bit++){ | |
108 | parityWd = (parityWd << 1) | BitSource[word+bit]; | |
109 | dest[j++] = (BitSource[word+bit]); | |
110 | } | |
111 | // if parity fails then return 0 | |
112 | switch (pType) { | |
113 | case 3: dest[j++]=0; break; // marker bit which should be a 0 | |
114 | case 2: dest[j++]=1; break; // marker bit which should be a 1 | |
115 | default: | |
116 | dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1; | |
117 | break; | |
118 | } | |
119 | bitCnt += pLen; | |
120 | parityWd = 0; | |
121 | } | |
122 | // if we got here then all the parities passed | |
123 | //return ID start index and size | |
124 | return bitCnt; | |
125 | } | |
126 | ||
127 | uint32_t bytebits_to_byte(uint8_t *src, size_t numbits) | |
128 | { | |
129 | uint32_t num = 0; | |
130 | for(int i = 0 ; i < numbits ; i++) | |
131 | { | |
132 | num = (num << 1) | (*src); | |
133 | src++; | |
134 | } | |
135 | return num; | |
136 | } | |
137 | ||
138 | //least significant bit first | |
139 | uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits) | |
140 | { | |
141 | uint32_t num = 0; | |
142 | for(int i = 0 ; i < numbits ; i++) | |
143 | { | |
144 | num = (num << 1) | *(src + (numbits-(i+1))); | |
145 | } | |
146 | return num; | |
147 | } | |
148 | ||
149 | //by marshmellow | |
150 | //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length | |
151 | uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx) | |
152 | { | |
153 | return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0; | |
154 | } | |
155 | ||
156 | // search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone | |
157 | // fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits | |
158 | bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) { | |
159 | // Sanity check. If preamble length is bigger than bitstream length. | |
160 | if ( *size <= pLen ) return false; | |
161 | ||
162 | uint8_t foundCnt = 0; | |
163 | for (size_t idx = 0; idx < *size - pLen; idx++) { | |
164 | if (memcmp(BitStream+idx, preamble, pLen) == 0) { | |
165 | //first index found | |
166 | foundCnt++; | |
167 | if (foundCnt == 1) { | |
168 | if (g_debugMode) prnt("DEBUG: preamble found at %u", idx); | |
169 | *startIdx = idx; | |
170 | if (findone) return true; | |
171 | } else if (foundCnt == 2) { | |
172 | *size = idx - *startIdx; | |
173 | return true; | |
174 | } | |
175 | } | |
176 | } | |
177 | return false; | |
178 | } | |
179 | ||
180 | // find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup. | |
181 | size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) { | |
182 | size_t i = 0; | |
183 | size_t waveSizeCnt = 0; | |
184 | uint8_t thresholdCnt = 0; | |
185 | bool isAboveThreshold = dest[i++] >= threshold_value; | |
186 | for (; i < size-20; i++ ) { | |
187 | if(dest[i] < threshold_value && isAboveThreshold) { | |
188 | thresholdCnt++; | |
189 | if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; | |
190 | isAboveThreshold = false; | |
191 | waveSizeCnt = 0; | |
192 | } else if (dest[i] >= threshold_value && !isAboveThreshold) { | |
193 | thresholdCnt++; | |
194 | if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break; | |
195 | isAboveThreshold = true; | |
196 | waveSizeCnt = 0; | |
197 | } else { | |
198 | waveSizeCnt++; | |
199 | } | |
200 | if (thresholdCnt > 10) break; | |
201 | } | |
202 | if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt); | |
203 | return i; | |
204 | } | |
205 | ||
206 | //by marshmellow | |
207 | //takes 1s and 0s and searches for EM410x format - output EM ID | |
208 | uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo) | |
209 | { | |
210 | //sanity checks | |
211 | if (*size < 64) return 0; | |
212 | if (BitStream[1]>1) return 0; //allow only 1s and 0s | |
213 | ||
214 | // 111111111 bit pattern represent start of frame | |
215 | // include 0 in front to help get start pos | |
216 | uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1}; | |
217 | uint8_t errChk = 0; | |
218 | uint8_t FmtLen = 10; // sets of 4 bits = end data | |
219 | *startIdx = 0; | |
220 | errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx); | |
221 | if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0; | |
222 | if (*size == 128) FmtLen = 22; // 22 sets of 4 bits | |
223 | ||
224 | //skip last 4bit parity row for simplicity | |
225 | *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5); | |
226 | if (*size == 40) { // std em410x format | |
227 | *hi = 0; | |
228 | *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32)); | |
229 | } else if (*size == 88) { // long em format | |
230 | *hi = (bytebits_to_byte(BitStream, 24)); | |
231 | *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32)); | |
232 | } else { | |
233 | return 0; | |
234 | } | |
235 | return 1; | |
236 | } | |
237 | ||
238 | //by marshmellow | |
239 | //demodulates strong heavily clipped samples | |
240 | int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx) | |
241 | { | |
242 | *startIdx=0; | |
243 | size_t bitCnt=0, smplCnt=1, errCnt=0; | |
244 | bool waveHigh = (BinStream[0] >= high); | |
245 | for (size_t i=1; i < *size; i++){ | |
246 | if (BinStream[i] >= high && waveHigh){ | |
247 | smplCnt++; | |
248 | } else if (BinStream[i] <= low && !waveHigh){ | |
249 | smplCnt++; | |
250 | } else { //transition | |
251 | if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){ | |
252 | if (smplCnt > clk-(clk/4)-1) { //full clock | |
253 | if (smplCnt > clk + (clk/4)+1) { //too many samples | |
254 | errCnt++; | |
255 | if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); | |
256 | BinStream[bitCnt++] = 7; | |
257 | } else if (waveHigh) { | |
258 | BinStream[bitCnt++] = invert; | |
259 | BinStream[bitCnt++] = invert; | |
260 | } else if (!waveHigh) { | |
261 | BinStream[bitCnt++] = invert ^ 1; | |
262 | BinStream[bitCnt++] = invert ^ 1; | |
263 | } | |
264 | if (*startIdx==0) *startIdx = i-clk; | |
265 | waveHigh = !waveHigh; | |
266 | smplCnt = 0; | |
267 | } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock | |
268 | if (waveHigh) { | |
269 | BinStream[bitCnt++] = invert; | |
270 | } else if (!waveHigh) { | |
271 | BinStream[bitCnt++] = invert ^ 1; | |
272 | } | |
273 | if (*startIdx==0) *startIdx = i-(clk/2); | |
274 | waveHigh = !waveHigh; | |
275 | smplCnt = 0; | |
276 | } else { | |
277 | smplCnt++; | |
278 | //transition bit oops | |
279 | } | |
280 | } else { //haven't hit new high or new low yet | |
281 | smplCnt++; | |
282 | } | |
283 | } | |
284 | } | |
285 | *size = bitCnt; | |
286 | return errCnt; | |
287 | } | |
288 | ||
289 | //by marshmellow | |
290 | //amplify based on ask edge detection | |
291 | void askAmp(uint8_t *BitStream, size_t size) | |
292 | { | |
293 | uint8_t Last = 128; | |
294 | for(size_t i = 1; i<size; i++){ | |
295 | if (BitStream[i]-BitStream[i-1]>=30) //large jump up | |
296 | Last = 255; | |
297 | else if(BitStream[i-1]-BitStream[i]>=20) //large jump down | |
298 | Last = 0; | |
299 | ||
300 | BitStream[i-1] = Last; | |
301 | } | |
302 | return; | |
303 | } | |
304 | ||
305 | //by marshmellow | |
306 | //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester | |
307 | int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) { | |
308 | if (*size==0) return -1; | |
309 | int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default | |
310 | if (*clk==0 || start < 0) return -3; | |
311 | if (*invert != 1) *invert = 0; | |
312 | if (amp==1) askAmp(BinStream, *size); | |
313 | if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp); | |
314 | ||
315 | //start pos from detect ask clock is 1/2 clock offset | |
316 | // NOTE: can be negative (demod assumes rest of wave was there) | |
317 | *startIdx = start - (*clk/2); | |
318 | uint8_t initLoopMax = 255; | |
319 | if (initLoopMax > *size) initLoopMax = *size; | |
320 | // Detect high and lows | |
321 | //25% clip in case highs and lows aren't clipped [marshmellow] | |
322 | int high, low; | |
323 | if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1) | |
324 | return -2; //just noise | |
325 | ||
326 | size_t errCnt = 0; | |
327 | // if clean clipped waves detected run alternate demod | |
328 | if (DetectCleanAskWave(BinStream, *size, high, low)) { | |
329 | if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod"); | |
330 | errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx); | |
331 | if (askType) { //askman | |
332 | uint8_t alignPos = 0; | |
333 | errCnt = manrawdecode(BinStream, size, 0, &alignPos); | |
334 | *startIdx += *clk/2 * alignPos; | |
335 | if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos); | |
336 | return errCnt; | |
337 | } else { //askraw | |
338 | return errCnt; | |
339 | } | |
340 | } | |
341 | if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx); | |
342 | if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod"); | |
343 | ||
344 | int lastBit; //set first clock check - can go negative | |
345 | size_t i, bitnum = 0; //output counter | |
346 | uint8_t midBit = 0; | |
347 | 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 | |
348 | 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 | |
349 | size_t MaxBits = 3072; //max bits to collect | |
350 | lastBit = start - *clk; | |
351 | ||
352 | for (i = start; i < *size; ++i) { | |
353 | if (i-lastBit >= *clk-tol){ | |
354 | if (BinStream[i] >= high) { | |
355 | BinStream[bitnum++] = *invert; | |
356 | } else if (BinStream[i] <= low) { | |
357 | BinStream[bitnum++] = *invert ^ 1; | |
358 | } else if (i-lastBit >= *clk+tol) { | |
359 | if (bitnum > 0) { | |
360 | if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i); | |
361 | BinStream[bitnum++]=7; | |
362 | errCnt++; | |
363 | } | |
364 | } else { //in tolerance - looking for peak | |
365 | continue; | |
366 | } | |
367 | midBit = 0; | |
368 | lastBit += *clk; | |
369 | } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){ | |
370 | if (BinStream[i] >= high) { | |
371 | BinStream[bitnum++] = *invert; | |
372 | } else if (BinStream[i] <= low) { | |
373 | BinStream[bitnum++] = *invert ^ 1; | |
374 | } else if (i-lastBit >= *clk/2+tol) { | |
375 | BinStream[bitnum] = BinStream[bitnum-1]; | |
376 | bitnum++; | |
377 | } else { //in tolerance - looking for peak | |
378 | continue; | |
379 | } | |
380 | midBit = 1; | |
381 | } | |
382 | if (bitnum >= MaxBits) break; | |
383 | } | |
384 | *size = bitnum; | |
385 | return errCnt; | |
386 | } | |
387 | ||
388 | int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) { | |
389 | int start = 0; | |
390 | return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start); | |
391 | } | |
392 | //by marshmellow | |
393 | //take 10 and 01 and manchester decode | |
394 | //run through 2 times and take least errCnt | |
395 | int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos) | |
396 | { | |
397 | uint16_t bitnum=0, MaxBits = 512, errCnt = 0; | |
398 | size_t i, ii; | |
399 | uint16_t bestErr = 1000, bestRun = 0; | |
400 | if (*size < 16) return -1; | |
401 | //find correct start position [alignment] | |
402 | for (ii=0;ii<2;++ii){ | |
403 | for (i=ii; i<*size-3; i+=2) | |
404 | if (BitStream[i]==BitStream[i+1]) | |
405 | errCnt++; | |
406 | ||
407 | if (bestErr>errCnt){ | |
408 | bestErr=errCnt; | |
409 | bestRun=ii; | |
410 | } | |
411 | errCnt=0; | |
412 | } | |
413 | *alignPos=bestRun; | |
414 | //decode | |
415 | for (i=bestRun; i < *size-3; i+=2){ | |
416 | if(BitStream[i] == 1 && (BitStream[i+1] == 0)){ | |
417 | BitStream[bitnum++]=invert; | |
418 | } else if((BitStream[i] == 0) && BitStream[i+1] == 1){ | |
419 | BitStream[bitnum++]=invert^1; | |
420 | } else { | |
421 | BitStream[bitnum++]=7; | |
422 | } | |
423 | if(bitnum>MaxBits) break; | |
424 | } | |
425 | *size=bitnum; | |
426 | return bestErr; | |
427 | } | |
428 | ||
429 | uint32_t manchesterEncode2Bytes(uint16_t datain) { | |
430 | uint32_t output = 0; | |
431 | uint8_t curBit = 0; | |
432 | for (uint8_t i=0; i<16; i++) { | |
433 | curBit = (datain >> (15-i) & 1); | |
434 | output |= (1<<(((15-i)*2)+curBit)); | |
435 | } | |
436 | return output; | |
437 | } | |
438 | ||
439 | //by marshmellow | |
440 | //encode binary data into binary manchester | |
441 | int ManchesterEncode(uint8_t *BitStream, size_t size) | |
442 | { | |
443 | size_t modIdx=20000, i=0; | |
444 | if (size>modIdx) return -1; | |
445 | for (size_t idx=0; idx < size; idx++){ | |
446 | BitStream[idx+modIdx++] = BitStream[idx]; | |
447 | BitStream[idx+modIdx++] = BitStream[idx]^1; | |
448 | } | |
449 | for (; i<(size*2); i++){ | |
450 | BitStream[i] = BitStream[i+20000]; | |
451 | } | |
452 | return i; | |
453 | } | |
454 | ||
455 | //by marshmellow | |
456 | //take 01 or 10 = 1 and 11 or 00 = 0 | |
457 | //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010 | |
458 | //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding | |
459 | int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert) | |
460 | { | |
461 | uint16_t bitnum = 0; | |
462 | uint16_t errCnt = 0; | |
463 | size_t i = offset; | |
464 | uint16_t MaxBits=512; | |
465 | //if not enough samples - error | |
466 | if (*size < 51) return -1; | |
467 | //check for phase change faults - skip one sample if faulty | |
468 | uint8_t offsetA = 1, offsetB = 1; | |
469 | for (; i<48; i+=2){ | |
470 | if (BitStream[i+1]==BitStream[i+2]) offsetA=0; | |
471 | if (BitStream[i+2]==BitStream[i+3]) offsetB=0; | |
472 | } | |
473 | if (!offsetA && offsetB) offset++; | |
474 | for (i=offset; i<*size-3; i+=2){ | |
475 | //check for phase error | |
476 | if (BitStream[i+1]==BitStream[i+2]) { | |
477 | BitStream[bitnum++]=7; | |
478 | errCnt++; | |
479 | } | |
480 | if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){ | |
481 | BitStream[bitnum++]=1^invert; | |
482 | } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){ | |
483 | BitStream[bitnum++]=invert; | |
484 | } else { | |
485 | BitStream[bitnum++]=7; | |
486 | errCnt++; | |
487 | } | |
488 | if(bitnum>MaxBits) break; | |
489 | } | |
490 | *size=bitnum; | |
491 | return errCnt; | |
492 | } | |
493 | ||
494 | // by marshmellow | |
495 | // demod gProxIIDemod | |
496 | // error returns as -x | |
497 | // success returns start position in BitStream | |
498 | // BitStream must contain previously askrawdemod and biphasedemoded data | |
499 | int gProxII_Demod(uint8_t BitStream[], size_t *size) | |
500 | { | |
501 | size_t startIdx=0; | |
502 | uint8_t preamble[] = {1,1,1,1,1,0}; | |
503 | ||
504 | uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx); | |
505 | if (errChk == 0) return -3; //preamble not found | |
506 | if (*size != 96) return -2; //should have found 96 bits | |
507 | //check first 6 spacer bits to verify format | |
508 | if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){ | |
509 | //confirmed proper separator bits found | |
510 | //return start position | |
511 | return (int) startIdx; | |
512 | } | |
513 | return -5; //spacer bits not found - not a valid gproxII | |
514 | } | |
515 | ||
516 | //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq]) | |
517 | size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx) | |
518 | { | |
519 | size_t last_transition = 0; | |
520 | size_t idx = 1; | |
521 | if (fchigh==0) fchigh=10; | |
522 | if (fclow==0) fclow=8; | |
523 | //set the threshold close to 0 (graph) or 128 std to avoid static | |
524 | uint8_t threshold_value = 123; | |
525 | size_t preLastSample = 0; | |
526 | size_t LastSample = 0; | |
527 | size_t currSample = 0; | |
528 | if ( size < 1024 ) return 0; // not enough samples | |
529 | ||
530 | //find start of modulating data in trace | |
531 | idx = findModStart(dest, size, threshold_value, fchigh); | |
532 | // Need to threshold first sample | |
533 | if(dest[idx] < threshold_value) dest[0] = 0; | |
534 | else dest[0] = 1; | |
535 | ||
536 | last_transition = idx; | |
537 | idx++; | |
538 | size_t numBits = 0; | |
539 | // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8) | |
540 | // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere | |
541 | // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10 | |
542 | // (could also be fc/5 && fc/7 for fsk1 = 4-9) | |
543 | for(; idx < size; idx++) { | |
544 | // threshold current value | |
545 | if (dest[idx] < threshold_value) dest[idx] = 0; | |
546 | else dest[idx] = 1; | |
547 | ||
548 | // Check for 0->1 transition | |
549 | if (dest[idx-1] < dest[idx]) { | |
550 | preLastSample = LastSample; | |
551 | LastSample = currSample; | |
552 | currSample = idx-last_transition; | |
553 | if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3) | |
554 | //do nothing with extra garbage | |
555 | } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5) | |
556 | //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5) | |
557 | if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){ | |
558 | dest[numBits-1]=1; | |
559 | } | |
560 | dest[numBits++]=1; | |
561 | if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow; | |
562 | } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage | |
563 | //do nothing with beginning garbage and reset.. should be rare.. | |
564 | numBits = 0; | |
565 | } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's) | |
566 | dest[numBits++]=1; | |
567 | if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow; | |
568 | } else { //9+ = 10 sample waves (or 6+ = 7) | |
569 | dest[numBits++]=0; | |
570 | if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh; | |
571 | } | |
572 | last_transition = idx; | |
573 | } | |
574 | } | |
575 | return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0 | |
576 | } | |
577 | ||
578 | //translate 11111100000 to 10 | |
579 | //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock | |
580 | size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, | |
581 | uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) | |
582 | { | |
583 | uint8_t lastval=dest[0]; | |
584 | size_t idx=0; | |
585 | size_t numBits=0; | |
586 | uint32_t n=1; | |
587 | for( idx=1; idx < size; idx++) { | |
588 | n++; | |
589 | if (dest[idx]==lastval) continue; //skip until we hit a transition | |
590 | ||
591 | //find out how many bits (n) we collected (use 1/2 clk tolerance) | |
592 | //if lastval was 1, we have a 1->0 crossing | |
593 | if (dest[idx-1]==1) { | |
594 | n = (n * fclow + rfLen/2) / rfLen; | |
595 | } else {// 0->1 crossing | |
596 | n = (n * fchigh + rfLen/2) / rfLen; | |
597 | } | |
598 | if (n == 0) n = 1; | |
599 | ||
600 | //first transition - save startidx | |
601 | if (numBits == 0) { | |
602 | if (lastval == 1) { //high to low | |
603 | *startIdx += (fclow * idx) - (n*rfLen); | |
604 | if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen); | |
605 | } else { | |
606 | *startIdx += (fchigh * idx) - (n*rfLen); | |
607 | if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen); | |
608 | } | |
609 | } | |
610 | ||
611 | //add to our destination the bits we collected | |
612 | memset(dest+numBits, dest[idx-1]^invert , n); | |
613 | numBits += n; | |
614 | n=0; | |
615 | lastval=dest[idx]; | |
616 | }//end for | |
617 | // if valid extra bits at the end were all the same frequency - add them in | |
618 | if (n > rfLen/fchigh) { | |
619 | if (dest[idx-2]==1) { | |
620 | n = (n * fclow + rfLen/2) / rfLen; | |
621 | } else { | |
622 | n = (n * fchigh + rfLen/2) / rfLen; | |
623 | } | |
624 | memset(dest+numBits, dest[idx-1]^invert , n); | |
625 | numBits += n; | |
626 | } | |
627 | return numBits; | |
628 | } | |
629 | ||
630 | //by marshmellow (from holiman's base) | |
631 | // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod) | |
632 | int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) { | |
633 | // FSK demodulator | |
634 | size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx); | |
635 | size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx); | |
636 | return size; | |
637 | } | |
638 | ||
639 | int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) { | |
640 | int startIdx=0; | |
641 | return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx); | |
642 | } | |
643 | ||
644 | // loop to get raw HID waveform then FSK demodulate the TAG ID from it | |
645 | int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) | |
646 | { | |
647 | if (justNoise(dest, *size)) return -1; | |
648 | ||
649 | size_t numStart=0, size2=*size, startIdx=0; | |
650 | // FSK demodulator | |
651 | *size = fskdemod(dest, size2,50,1,10,8); //fsk2a | |
652 | if (*size < 96*2) return -2; | |
653 | // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 | |
654 | uint8_t preamble[] = {0,0,0,1,1,1,0,1}; | |
655 | // find bitstring in array | |
656 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
657 | if (errChk == 0) return -3; //preamble not found | |
658 | ||
659 | numStart = startIdx + sizeof(preamble); | |
660 | // final loop, go over previously decoded FSK data and manchester decode into usable tag ID | |
661 | for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ | |
662 | if (dest[idx] == dest[idx+1]){ | |
663 | return -4; //not manchester data | |
664 | } | |
665 | *hi2 = (*hi2<<1)|(*hi>>31); | |
666 | *hi = (*hi<<1)|(*lo>>31); | |
667 | //Then, shift in a 0 or one into low | |
668 | if (dest[idx] && !dest[idx+1]) // 1 0 | |
669 | *lo=(*lo<<1)|1; | |
670 | else // 0 1 | |
671 | *lo=(*lo<<1)|0; | |
672 | } | |
673 | return (int)startIdx; | |
674 | } | |
675 | ||
676 | // loop to get raw paradox waveform then FSK demodulate the TAG ID from it | |
677 | int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo) | |
678 | { | |
679 | if (justNoise(dest, *size)) return -1; | |
680 | ||
681 | size_t numStart=0, size2=*size, startIdx=0; | |
682 | // FSK demodulator | |
683 | *size = fskdemod(dest, size2,50,1,10,8); //fsk2a | |
684 | if (*size < 96) return -2; | |
685 | ||
686 | // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1 | |
687 | uint8_t preamble[] = {0,0,0,0,1,1,1,1}; | |
688 | ||
689 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
690 | if (errChk == 0) return -3; //preamble not found | |
691 | ||
692 | numStart = startIdx + sizeof(preamble); | |
693 | // final loop, go over previously decoded FSK data and manchester decode into usable tag ID | |
694 | for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){ | |
695 | if (dest[idx] == dest[idx+1]) | |
696 | return -4; //not manchester data | |
697 | *hi2 = (*hi2<<1)|(*hi>>31); | |
698 | *hi = (*hi<<1)|(*lo>>31); | |
699 | //Then, shift in a 0 or one into low | |
700 | if (dest[idx] && !dest[idx+1]) // 1 0 | |
701 | *lo=(*lo<<1)|1; | |
702 | else // 0 1 | |
703 | *lo=(*lo<<1)|0; | |
704 | } | |
705 | return (int)startIdx; | |
706 | } | |
707 | ||
708 | int IOdemodFSK(uint8_t *dest, size_t size) | |
709 | { | |
710 | if (justNoise(dest, size)) return -1; | |
711 | //make sure buffer has data | |
712 | if (size < 66*64) return -2; | |
713 | // FSK demodulator | |
714 | size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64 | |
715 | if (size < 65) return -3; //did we get a good demod? | |
716 | //Index map | |
717 | //0 10 20 30 40 50 60 | |
718 | //| | | | | | | | |
719 | //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23 | |
720 | //----------------------------------------------------------------------------- | |
721 | //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11 | |
722 | // | |
723 | //XSF(version)facility:codeone+codetwo | |
724 | //Handle the data | |
725 | size_t startIdx = 0; | |
726 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1}; | |
727 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx); | |
728 | if (errChk == 0) return -4; //preamble not found | |
729 | ||
730 | if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){ | |
731 | //confirmed proper separator bits found | |
732 | //return start position | |
733 | return (int) startIdx; | |
734 | } | |
735 | return -5; | |
736 | } | |
737 | ||
738 | // by marshmellow | |
739 | // find viking preamble 0xF200 in already demoded data | |
740 | int VikingDemod_AM(uint8_t *dest, size_t *size) { | |
741 | //make sure buffer has data | |
742 | if (*size < 64*2) return -2; | |
743 | ||
744 | size_t startIdx = 0; | |
745 | 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}; | |
746 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
747 | if (errChk == 0) return -4; //preamble not found | |
748 | uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8) | |
749 | ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8) | |
750 | ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8); | |
751 | if ( checkCalc != 0xA8 ) return -5; | |
752 | if (*size != 64) return -6; | |
753 | //return start position | |
754 | return (int) startIdx; | |
755 | } | |
756 | ||
757 | // find presco preamble 0x10D in already demoded data | |
758 | int PrescoDemod(uint8_t *dest, size_t *size) { | |
759 | //make sure buffer has data | |
760 | if (*size < 64*2) return -2; | |
761 | ||
762 | size_t startIdx = 0; | |
763 | uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0}; | |
764 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
765 | if (errChk == 0) return -4; //preamble not found | |
766 | //return start position | |
767 | return (int) startIdx; | |
768 | } | |
769 | ||
770 | // Ask/Biphase Demod then try to locate an ISO 11784/85 ID | |
771 | // BitStream must contain previously askrawdemod and biphasedemoded data | |
772 | int FDXBdemodBI(uint8_t *dest, size_t *size) | |
773 | { | |
774 | //make sure buffer has enough data | |
775 | if (*size < 128) return -1; | |
776 | ||
777 | size_t startIdx = 0; | |
778 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1}; | |
779 | ||
780 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
781 | if (errChk == 0) return -2; //preamble not found | |
782 | return (int)startIdx; | |
783 | } | |
784 | ||
785 | // by marshmellow | |
786 | // FSK Demod then try to locate an AWID ID | |
787 | int AWIDdemodFSK(uint8_t *dest, size_t *size) | |
788 | { | |
789 | //make sure buffer has enough data | |
790 | if (*size < 96*50) return -1; | |
791 | ||
792 | if (justNoise(dest, *size)) return -2; | |
793 | ||
794 | // FSK demodulator | |
795 | *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 | |
796 | if (*size < 96) return -3; //did we get a good demod? | |
797 | ||
798 | uint8_t preamble[] = {0,0,0,0,0,0,0,1}; | |
799 | size_t startIdx = 0; | |
800 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
801 | if (errChk == 0) return -4; //preamble not found | |
802 | if (*size != 96) return -5; | |
803 | return (int)startIdx; | |
804 | } | |
805 | ||
806 | // by marshmellow | |
807 | // FSK Demod then try to locate a Farpointe Data (pyramid) ID | |
808 | int PyramiddemodFSK(uint8_t *dest, size_t *size) | |
809 | { | |
810 | //make sure buffer has data | |
811 | if (*size < 128*50) return -5; | |
812 | ||
813 | //test samples are not just noise | |
814 | if (justNoise(dest, *size)) return -1; | |
815 | ||
816 | // FSK demodulator | |
817 | *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50 | |
818 | if (*size < 128) return -2; //did we get a good demod? | |
819 | ||
820 | uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1}; | |
821 | size_t startIdx = 0; | |
822 | uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx); | |
823 | if (errChk == 0) return -4; //preamble not found | |
824 | if (*size != 128) return -3; | |
825 | return (int)startIdx; | |
826 | } | |
827 | ||
828 | // by marshmellow | |
829 | // to detect a wave that has heavily clipped (clean) samples | |
830 | uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low) | |
831 | { | |
832 | bool allArePeaks = true; | |
833 | uint16_t cntPeaks=0; | |
834 | size_t loopEnd = 512+160; | |
835 | if (loopEnd > size) loopEnd = size; | |
836 | for (size_t i=160; i<loopEnd; i++){ | |
837 | if (dest[i]>low && dest[i]<high) | |
838 | allArePeaks = false; | |
839 | else | |
840 | cntPeaks++; | |
841 | } | |
842 | if (!allArePeaks){ | |
843 | if (cntPeaks > 300) return true; | |
844 | } | |
845 | return allArePeaks; | |
846 | } | |
847 | // by marshmellow | |
848 | // to help detect clocks on heavily clipped samples | |
849 | // based on count of low to low | |
850 | int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock) { | |
851 | uint8_t fndClk[] = {8,16,32,40,50,64,128}; | |
852 | size_t startwave; | |
853 | size_t i = 100; | |
854 | size_t minClk = 255; | |
855 | int shortestWaveIdx = 0; | |
856 | // get to first full low to prime loop and skip incomplete first pulse | |
857 | while ((dest[i] < high) && (i < size)) | |
858 | ++i; | |
859 | while ((dest[i] > low) && (i < size)) | |
860 | ++i; | |
861 | ||
862 | // loop through all samples | |
863 | while (i < size) { | |
864 | // measure from low to low | |
865 | while ((dest[i] > low) && (i < size)) | |
866 | ++i; | |
867 | startwave = i; | |
868 | while ((dest[i] < high) && (i < size)) | |
869 | ++i; | |
870 | while ((dest[i] > low) && (i < size)) | |
871 | ++i; | |
872 | //get minimum measured distance | |
873 | if (i-startwave < minClk && i < size) { | |
874 | minClk = i - startwave; | |
875 | shortestWaveIdx = startwave; | |
876 | } | |
877 | } | |
878 | // set clock | |
879 | if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk); | |
880 | for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { | |
881 | if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) { | |
882 | *clock = fndClk[clkCnt]; | |
883 | return shortestWaveIdx; | |
884 | } | |
885 | } | |
886 | return 0; | |
887 | } | |
888 | ||
889 | // by marshmellow | |
890 | // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping) | |
891 | // maybe somehow adjust peak trimming value based on samples to fix? | |
892 | // return start index of best starting position for that clock and return clock (by reference) | |
893 | int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr) | |
894 | { | |
895 | size_t i=1; | |
896 | uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255}; | |
897 | uint8_t clkEnd = 9; | |
898 | uint8_t loopCnt = 255; //don't need to loop through entire array... | |
899 | if (size <= loopCnt+60) return -1; //not enough samples | |
900 | size -= 60; //sometimes there is a strange end wave - filter out this.... | |
901 | //if we already have a valid clock | |
902 | uint8_t clockFnd=0; | |
903 | for (;i<clkEnd;++i) | |
904 | if (clk[i] == *clock) clockFnd = i; | |
905 | //clock found but continue to find best startpos | |
906 | ||
907 | //get high and low peak | |
908 | int peak, low; | |
909 | if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1; | |
910 | ||
911 | //test for large clean peaks | |
912 | if (!clockFnd){ | |
913 | if (DetectCleanAskWave(dest, size, peak, low)==1){ | |
914 | int ans = DetectStrongAskClock(dest, size, peak, low, clock); | |
915 | if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans); | |
916 | if (ans > 0) { | |
917 | return ans; //return shortest wave start position | |
918 | } | |
919 | } | |
920 | } | |
921 | uint8_t ii; | |
922 | uint8_t clkCnt, tol = 0; | |
923 | uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; | |
924 | uint8_t bestStart[]={0,0,0,0,0,0,0,0,0}; | |
925 | size_t errCnt = 0; | |
926 | size_t arrLoc, loopEnd; | |
927 | ||
928 | if (clockFnd>0) { | |
929 | clkCnt = clockFnd; | |
930 | clkEnd = clockFnd+1; | |
931 | } | |
932 | else clkCnt=1; | |
933 | ||
934 | //test each valid clock from smallest to greatest to see which lines up | |
935 | for(; clkCnt < clkEnd; clkCnt++){ | |
936 | if (clk[clkCnt] <= 32){ | |
937 | tol=1; | |
938 | }else{ | |
939 | tol=0; | |
940 | } | |
941 | //if no errors allowed - keep start within the first clock | |
942 | if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2; | |
943 | bestErr[clkCnt]=1000; | |
944 | //try lining up the peaks by moving starting point (try first few clocks) | |
945 | for (ii=0; ii < loopCnt; ii++){ | |
946 | if (dest[ii] < peak && dest[ii] > low) continue; | |
947 | ||
948 | errCnt=0; | |
949 | // now that we have the first one lined up test rest of wave array | |
950 | loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1; | |
951 | for (i=0; i < loopEnd; ++i){ | |
952 | arrLoc = ii + (i * clk[clkCnt]); | |
953 | if (dest[arrLoc] >= peak || dest[arrLoc] <= low){ | |
954 | }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){ | |
955 | }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){ | |
956 | }else{ //error no peak detected | |
957 | errCnt++; | |
958 | } | |
959 | } | |
960 | //if we found no errors then we can stop here and a low clock (common clocks) | |
961 | // this is correct one - return this clock | |
962 | if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i); | |
963 | if(errCnt==0 && clkCnt<7) { | |
964 | if (!clockFnd) *clock = clk[clkCnt]; | |
965 | return ii; | |
966 | } | |
967 | //if we found errors see if it is lowest so far and save it as best run | |
968 | if(errCnt<bestErr[clkCnt]){ | |
969 | bestErr[clkCnt]=errCnt; | |
970 | bestStart[clkCnt]=ii; | |
971 | } | |
972 | } | |
973 | } | |
974 | uint8_t iii; | |
975 | uint8_t best=0; | |
976 | for (iii=1; iii<clkEnd; ++iii){ | |
977 | if (bestErr[iii] < bestErr[best]){ | |
978 | if (bestErr[iii] == 0) bestErr[iii]=1; | |
979 | // current best bit to error ratio vs new bit to error ratio | |
980 | if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){ | |
981 | best = iii; | |
982 | } | |
983 | } | |
984 | if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d",clk[iii],bestErr[iii],clk[best],bestStart[best]); | |
985 | } | |
986 | if (!clockFnd) *clock = clk[best]; | |
987 | return bestStart[best]; | |
988 | } | |
989 | ||
990 | //by marshmellow | |
991 | //detect psk clock by reading each phase shift | |
992 | // a phase shift is determined by measuring the sample length of each wave | |
993 | int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) { | |
994 | uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock | |
995 | uint16_t loopCnt = 4096; //don't need to loop through entire array... | |
996 | if (size == 0) return 0; | |
997 | if (size<loopCnt) loopCnt = size-20; | |
998 | ||
999 | //if we already have a valid clock quit | |
1000 | size_t i=1; | |
1001 | for (; i < 8; ++i) | |
1002 | if (clk[i] == clock) return clock; | |
1003 | ||
1004 | size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0; | |
1005 | uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1; | |
1006 | uint16_t peakcnt=0, errCnt=0, waveLenCnt=0; | |
1007 | uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000}; | |
1008 | uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0}; | |
1009 | fc = countFC(dest, size, 0); | |
1010 | if (fc!=2 && fc!=4 && fc!=8) return -1; | |
1011 | if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc); | |
1012 | ||
1013 | //find first full wave | |
1014 | for (i=160; i<loopCnt; i++){ | |
1015 | if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1016 | if (waveStart == 0) { | |
1017 | waveStart = i+1; | |
1018 | //prnt("DEBUG: waveStart: %d",waveStart); | |
1019 | } else { | |
1020 | waveEnd = i+1; | |
1021 | //prnt("DEBUG: waveEnd: %d",waveEnd); | |
1022 | waveLenCnt = waveEnd-waveStart; | |
1023 | if (waveLenCnt > fc){ | |
1024 | firstFullWave = waveStart; | |
1025 | fullWaveLen=waveLenCnt; | |
1026 | break; | |
1027 | } | |
1028 | waveStart=0; | |
1029 | } | |
1030 | } | |
1031 | } | |
1032 | *firstPhaseShift = firstFullWave; | |
1033 | if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen); | |
1034 | //test each valid clock from greatest to smallest to see which lines up | |
1035 | for(clkCnt=7; clkCnt >= 1 ; clkCnt--){ | |
1036 | lastClkBit = firstFullWave; //set end of wave as clock align | |
1037 | waveStart = 0; | |
1038 | errCnt=0; | |
1039 | peakcnt=0; | |
1040 | if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit); | |
1041 | ||
1042 | for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){ | |
1043 | //top edge of wave = start of new wave | |
1044 | if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1045 | if (waveStart == 0) { | |
1046 | waveStart = i+1; | |
1047 | waveLenCnt=0; | |
1048 | } else { //waveEnd | |
1049 | waveEnd = i+1; | |
1050 | waveLenCnt = waveEnd-waveStart; | |
1051 | if (waveLenCnt > fc){ | |
1052 | //if this wave is a phase shift | |
1053 | if (g_debugMode == 2) prnt("DEBUG PSK: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+clk[clkCnt]-tol,i+1,fc); | |
1054 | if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit | |
1055 | peakcnt++; | |
1056 | lastClkBit+=clk[clkCnt]; | |
1057 | } else if (i<lastClkBit+8){ | |
1058 | //noise after a phase shift - ignore | |
1059 | } else { //phase shift before supposed to based on clock | |
1060 | errCnt++; | |
1061 | } | |
1062 | } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){ | |
1063 | lastClkBit+=clk[clkCnt]; //no phase shift but clock bit | |
1064 | } | |
1065 | waveStart=i+1; | |
1066 | } | |
1067 | } | |
1068 | } | |
1069 | if (errCnt == 0){ | |
1070 | return clk[clkCnt]; | |
1071 | } | |
1072 | if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt; | |
1073 | if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt; | |
1074 | } | |
1075 | //all tested with errors | |
1076 | //return the highest clk with the most peaks found | |
1077 | uint8_t best=7; | |
1078 | for (i=7; i>=1; i--){ | |
1079 | if (peaksdet[i] > peaksdet[best]) { | |
1080 | best = i; | |
1081 | } | |
1082 | if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]); | |
1083 | } | |
1084 | return clk[best]; | |
1085 | } | |
1086 | ||
1087 | int DetectPSKClock(uint8_t dest[], size_t size, int clock) { | |
1088 | int firstPhaseShift = 0; | |
1089 | return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift); | |
1090 | } | |
1091 | ||
1092 | int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){ | |
1093 | //find shortest transition from high to low | |
1094 | size_t i = 0; | |
1095 | size_t transition1 = 0; | |
1096 | int lowestTransition = 255; | |
1097 | bool lastWasHigh = false; | |
1098 | ||
1099 | //find first valid beginning of a high or low wave | |
1100 | while ((dest[i] >= peak || dest[i] <= low) && (i < size)) | |
1101 | ++i; | |
1102 | while ((dest[i] < peak && dest[i] > low) && (i < size)) | |
1103 | ++i; | |
1104 | lastWasHigh = (dest[i] >= peak); | |
1105 | ||
1106 | if (i==size) return 0; | |
1107 | transition1 = i; | |
1108 | ||
1109 | for (;i < size; i++) { | |
1110 | if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) { | |
1111 | lastWasHigh = (dest[i] >= peak); | |
1112 | if (i-transition1 < lowestTransition) lowestTransition = i-transition1; | |
1113 | transition1 = i; | |
1114 | } | |
1115 | } | |
1116 | if (lowestTransition == 255) lowestTransition = 0; | |
1117 | if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition); | |
1118 | return lowestTransition; | |
1119 | } | |
1120 | ||
1121 | //by marshmellow | |
1122 | //detect nrz clock by reading #peaks vs no peaks(or errors) | |
1123 | int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) { | |
1124 | size_t i=0; | |
1125 | uint8_t clk[]={8,16,32,40,50,64,100,128,255}; | |
1126 | size_t loopCnt = 4096; //don't need to loop through entire array... | |
1127 | if (size == 0) return 0; | |
1128 | if (size<loopCnt) loopCnt = size-20; | |
1129 | //if we already have a valid clock quit | |
1130 | for (; i < 8; ++i) | |
1131 | if (clk[i] == clock) return clock; | |
1132 | ||
1133 | //get high and low peak | |
1134 | int peak, low; | |
1135 | if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0; | |
1136 | ||
1137 | int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low); | |
1138 | size_t ii; | |
1139 | uint8_t clkCnt; | |
1140 | uint8_t tol = 0; | |
1141 | uint16_t smplCnt = 0; | |
1142 | int16_t peakcnt = 0; | |
1143 | int16_t peaksdet[] = {0,0,0,0,0,0,0,0}; | |
1144 | uint16_t maxPeak = 255; | |
1145 | bool firstpeak = false; | |
1146 | //test for large clipped waves | |
1147 | for (i=0; i<loopCnt; i++){ | |
1148 | if (dest[i] >= peak || dest[i] <= low){ | |
1149 | if (!firstpeak) continue; | |
1150 | smplCnt++; | |
1151 | } else { | |
1152 | firstpeak=true; | |
1153 | if (smplCnt > 6 ){ | |
1154 | if (maxPeak > smplCnt){ | |
1155 | maxPeak = smplCnt; | |
1156 | //prnt("maxPk: %d",maxPeak); | |
1157 | } | |
1158 | peakcnt++; | |
1159 | //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt); | |
1160 | smplCnt=0; | |
1161 | } | |
1162 | } | |
1163 | } | |
1164 | bool errBitHigh = 0; | |
1165 | bool bitHigh = 0; | |
1166 | uint8_t ignoreCnt = 0; | |
1167 | uint8_t ignoreWindow = 4; | |
1168 | bool lastPeakHigh = 0; | |
1169 | int lastBit = 0; | |
1170 | size_t bestStart[]={0,0,0,0,0,0,0,0,0}; | |
1171 | peakcnt=0; | |
1172 | //test each valid clock from smallest to greatest to see which lines up | |
1173 | for(clkCnt=0; clkCnt < 8; ++clkCnt){ | |
1174 | //ignore clocks smaller than smallest peak | |
1175 | if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue; | |
1176 | //try lining up the peaks by moving starting point (try first 256) | |
1177 | for (ii=20; ii < loopCnt; ++ii){ | |
1178 | if ((dest[ii] >= peak) || (dest[ii] <= low)){ | |
1179 | peakcnt = 0; | |
1180 | bitHigh = false; | |
1181 | ignoreCnt = 0; | |
1182 | lastBit = ii-clk[clkCnt]; | |
1183 | //loop through to see if this start location works | |
1184 | for (i = ii; i < size-20; ++i) { | |
1185 | //if we are at a clock bit | |
1186 | if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) { | |
1187 | //test high/low | |
1188 | if (dest[i] >= peak || dest[i] <= low) { | |
1189 | //if same peak don't count it | |
1190 | if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) { | |
1191 | peakcnt++; | |
1192 | } | |
1193 | lastPeakHigh = (dest[i] >= peak); | |
1194 | bitHigh = true; | |
1195 | errBitHigh = false; | |
1196 | ignoreCnt = ignoreWindow; | |
1197 | lastBit += clk[clkCnt]; | |
1198 | } else if (i == lastBit + clk[clkCnt] + tol) { | |
1199 | lastBit += clk[clkCnt]; | |
1200 | } | |
1201 | //else if not a clock bit and no peaks | |
1202 | } else if (dest[i] < peak && dest[i] > low){ | |
1203 | if (ignoreCnt==0){ | |
1204 | bitHigh=false; | |
1205 | if (errBitHigh==true) peakcnt--; | |
1206 | errBitHigh=false; | |
1207 | } else { | |
1208 | ignoreCnt--; | |
1209 | } | |
1210 | // else if not a clock bit but we have a peak | |
1211 | } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) { | |
1212 | //error bar found no clock... | |
1213 | errBitHigh=true; | |
1214 | } | |
1215 | } | |
1216 | if(peakcnt>peaksdet[clkCnt]) { | |
1217 | bestStart[clkCnt]=ii; | |
1218 | peaksdet[clkCnt]=peakcnt; | |
1219 | } | |
1220 | } | |
1221 | } | |
1222 | } | |
1223 | int iii=7; | |
1224 | uint8_t best=0; | |
1225 | for (iii=7; iii > 0; iii--){ | |
1226 | if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) { | |
1227 | if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) { | |
1228 | best = iii; | |
1229 | } | |
1230 | } else if (peaksdet[iii] > peaksdet[best]){ | |
1231 | best = iii; | |
1232 | } | |
1233 | if (g_debugMode==2) prnt("DEBUG NRZ: Clk: %d, peaks: %d, maxPeak: %d, bestClk: %d, lowestTrs: %d",clk[iii],peaksdet[iii],maxPeak, clk[best], lowestTransition); | |
1234 | } | |
1235 | *clockStartIdx = bestStart[best]; | |
1236 | return clk[best]; | |
1237 | } | |
1238 | ||
1239 | int DetectNRZClock(uint8_t dest[], size_t size, int clock) { | |
1240 | size_t bestStart=0; | |
1241 | return DetectNRZClock_ext(dest, size, clock, &bestStart); | |
1242 | } | |
1243 | ||
1244 | // by marshmellow | |
1245 | // convert psk1 demod to psk2 demod | |
1246 | // only transition waves are 1s | |
1247 | void psk1TOpsk2(uint8_t *BitStream, size_t size) | |
1248 | { | |
1249 | size_t i=1; | |
1250 | uint8_t lastBit=BitStream[0]; | |
1251 | for (; i<size; i++){ | |
1252 | if (BitStream[i]==7){ | |
1253 | //ignore errors | |
1254 | } else if (lastBit!=BitStream[i]){ | |
1255 | lastBit=BitStream[i]; | |
1256 | BitStream[i]=1; | |
1257 | } else { | |
1258 | BitStream[i]=0; | |
1259 | } | |
1260 | } | |
1261 | return; | |
1262 | } | |
1263 | ||
1264 | // by marshmellow | |
1265 | // convert psk2 demod to psk1 demod | |
1266 | // from only transition waves are 1s to phase shifts change bit | |
1267 | void psk2TOpsk1(uint8_t *BitStream, size_t size) | |
1268 | { | |
1269 | uint8_t phase=0; | |
1270 | for (size_t i=0; i<size; i++){ | |
1271 | if (BitStream[i]==1){ | |
1272 | phase ^=1; | |
1273 | } | |
1274 | BitStream[i]=phase; | |
1275 | } | |
1276 | return; | |
1277 | } | |
1278 | ||
1279 | // redesigned by marshmellow adjusted from existing decode functions | |
1280 | // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more | |
1281 | int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert) | |
1282 | { | |
1283 | //26 bit 40134 format (don't know other formats) | |
1284 | 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}; | |
1285 | 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}; | |
1286 | size_t startidx = 0; | |
1287 | if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){ | |
1288 | // if didn't find preamble try again inverting | |
1289 | if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1; | |
1290 | *invert ^= 1; | |
1291 | } | |
1292 | if (*size != 64 && *size != 224) return -2; | |
1293 | if (*invert==1) | |
1294 | for (size_t i = startidx; i < *size; i++) | |
1295 | bitStream[i] ^= 1; | |
1296 | ||
1297 | return (int) startidx; | |
1298 | } | |
1299 | ||
1300 | // by marshmellow - demodulate NRZ wave - requires a read with strong signal | |
1301 | // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak | |
1302 | int nrzRawDemod_ext(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) { | |
1303 | if (justNoise(dest, *size)) return -1; | |
1304 | *clk = DetectNRZClock(dest, *size, *clk); | |
1305 | if (*clk==0) return -2; | |
1306 | size_t i, gLen = 4096; | |
1307 | if (gLen>*size) gLen = *size-20; | |
1308 | int high, low; | |
1309 | if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low | |
1310 | ||
1311 | uint8_t bit=0; | |
1312 | //convert wave samples to 1's and 0's | |
1313 | for(i=20; i < *size-20; i++){ | |
1314 | if (dest[i] >= high) bit = 1; | |
1315 | if (dest[i] <= low) bit = 0; | |
1316 | dest[i] = bit; | |
1317 | } | |
1318 | //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit) | |
1319 | size_t lastBit = 0; | |
1320 | size_t numBits = 0; | |
1321 | for(i=21; i < *size-20; i++) { | |
1322 | //if transition detected or large number of same bits - store the passed bits | |
1323 | if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) { | |
1324 | memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk); | |
1325 | numBits += (i - lastBit + (*clk/4)) / *clk; | |
1326 | if (lastBit == 0) { | |
1327 | *startIdx = i - (numBits * *clk); | |
1328 | if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx); | |
1329 | } | |
1330 | lastBit = i-1; | |
1331 | } | |
1332 | } | |
1333 | *size = numBits; | |
1334 | return 0; | |
1335 | } | |
1336 | int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) { | |
1337 | int startIdx = 0; | |
1338 | return nrzRawDemod_ext(dest, size, clk, invert, &startIdx); | |
1339 | } | |
1340 | ||
1341 | //by marshmellow | |
1342 | //detects the bit clock for FSK given the high and low Field Clocks | |
1343 | uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) { | |
1344 | uint8_t clk[] = {8,16,32,40,50,64,100,128,0}; | |
1345 | uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1346 | uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1347 | uint8_t rfLensFnd = 0; | |
1348 | uint8_t lastFCcnt = 0; | |
1349 | uint16_t fcCounter = 0; | |
1350 | uint16_t rfCounter = 0; | |
1351 | uint8_t firstBitFnd = 0; | |
1352 | size_t i; | |
1353 | if (size == 0) return 0; | |
1354 | ||
1355 | uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2); | |
1356 | rfLensFnd=0; | |
1357 | fcCounter=0; | |
1358 | rfCounter=0; | |
1359 | firstBitFnd=0; | |
1360 | //PrintAndLog("DEBUG: fcTol: %d",fcTol); | |
1361 | // prime i to first peak / up transition | |
1362 | for (i = 160; i < size-20; i++) | |
1363 | if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1]) | |
1364 | break; | |
1365 | ||
1366 | for (; i < size-20; i++){ | |
1367 | fcCounter++; | |
1368 | rfCounter++; | |
1369 | ||
1370 | if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1]) | |
1371 | continue; | |
1372 | // else new peak | |
1373 | // if we got less than the small fc + tolerance then set it to the small fc | |
1374 | // if it is inbetween set it to the last counter | |
1375 | if (fcCounter < fcHigh && fcCounter > fcLow) | |
1376 | fcCounter = lastFCcnt; | |
1377 | else if (fcCounter < fcLow+fcTol) | |
1378 | fcCounter = fcLow; | |
1379 | else //set it to the large fc | |
1380 | fcCounter = fcHigh; | |
1381 | ||
1382 | //look for bit clock (rf/xx) | |
1383 | if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){ | |
1384 | //not the same size as the last wave - start of new bit sequence | |
1385 | if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit | |
1386 | for (int ii=0; ii<15; ii++){ | |
1387 | if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){ | |
1388 | rfCnts[ii]++; | |
1389 | rfCounter = 0; | |
1390 | break; | |
1391 | } | |
1392 | } | |
1393 | if (rfCounter > 0 && rfLensFnd < 15){ | |
1394 | //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter); | |
1395 | rfCnts[rfLensFnd]++; | |
1396 | rfLens[rfLensFnd++] = rfCounter; | |
1397 | } | |
1398 | } else { | |
1399 | *firstClockEdge = i; | |
1400 | firstBitFnd++; | |
1401 | } | |
1402 | rfCounter=0; | |
1403 | lastFCcnt=fcCounter; | |
1404 | } | |
1405 | fcCounter=0; | |
1406 | } | |
1407 | uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15; | |
1408 | ||
1409 | for (i=0; i<15; i++){ | |
1410 | //get highest 2 RF values (might need to get more values to compare or compare all?) | |
1411 | if (rfCnts[i]>rfCnts[rfHighest]){ | |
1412 | rfHighest3=rfHighest2; | |
1413 | rfHighest2=rfHighest; | |
1414 | rfHighest=i; | |
1415 | } else if(rfCnts[i]>rfCnts[rfHighest2]){ | |
1416 | rfHighest3=rfHighest2; | |
1417 | rfHighest2=i; | |
1418 | } else if(rfCnts[i]>rfCnts[rfHighest3]){ | |
1419 | rfHighest3=i; | |
1420 | } | |
1421 | if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]); | |
1422 | } | |
1423 | // set allowed clock remainder tolerance to be 1 large field clock length+1 | |
1424 | // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off | |
1425 | uint8_t tol1 = fcHigh+1; | |
1426 | ||
1427 | if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]); | |
1428 | ||
1429 | // loop to find the highest clock that has a remainder less than the tolerance | |
1430 | // compare samples counted divided by | |
1431 | // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less) | |
1432 | int ii=7; | |
1433 | for (; ii>=2; ii--){ | |
1434 | if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){ | |
1435 | if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){ | |
1436 | if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){ | |
1437 | if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]); | |
1438 | break; | |
1439 | } | |
1440 | } | |
1441 | } | |
1442 | } | |
1443 | ||
1444 | if (ii<2) return 0; // oops we went too far | |
1445 | ||
1446 | return clk[ii]; | |
1447 | } | |
1448 | ||
1449 | uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) { | |
1450 | int firstClockEdge = 0; | |
1451 | return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge); | |
1452 | } | |
1453 | ||
1454 | //by marshmellow | |
1455 | //countFC is to detect the field clock lengths. | |
1456 | //counts and returns the 2 most common wave lengths | |
1457 | //mainly used for FSK field clock detection | |
1458 | uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj) | |
1459 | { | |
1460 | uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1461 | uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0}; | |
1462 | uint8_t fcLensFnd = 0; | |
1463 | uint8_t lastFCcnt = 0; | |
1464 | uint8_t fcCounter = 0; | |
1465 | size_t i; | |
1466 | if (size < 180) return 0; | |
1467 | ||
1468 | // prime i to first up transition | |
1469 | for (i = 160; i < size-20; i++) | |
1470 | if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]) | |
1471 | break; | |
1472 | ||
1473 | for (; i < size-20; i++){ | |
1474 | if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){ | |
1475 | // new up transition | |
1476 | fcCounter++; | |
1477 | if (fskAdj){ | |
1478 | //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8) | |
1479 | if (lastFCcnt==5 && fcCounter==9) fcCounter--; | |
1480 | //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5) | |
1481 | if ((fcCounter==9) || fcCounter==4) fcCounter++; | |
1482 | // save last field clock count (fc/xx) | |
1483 | lastFCcnt = fcCounter; | |
1484 | } | |
1485 | // find which fcLens to save it to: | |
1486 | for (int ii=0; ii<15; ii++){ | |
1487 | if (fcLens[ii]==fcCounter){ | |
1488 | fcCnts[ii]++; | |
1489 | fcCounter=0; | |
1490 | break; | |
1491 | } | |
1492 | } | |
1493 | if (fcCounter>0 && fcLensFnd<15){ | |
1494 | //add new fc length | |
1495 | fcCnts[fcLensFnd]++; | |
1496 | fcLens[fcLensFnd++]=fcCounter; | |
1497 | } | |
1498 | fcCounter=0; | |
1499 | } else { | |
1500 | // count sample | |
1501 | fcCounter++; | |
1502 | } | |
1503 | } | |
1504 | ||
1505 | uint8_t best1=14, best2=14, best3=14; | |
1506 | uint16_t maxCnt1=0; | |
1507 | // go through fclens and find which ones are bigest 2 | |
1508 | for (i=0; i<15; i++){ | |
1509 | // get the 3 best FC values | |
1510 | if (fcCnts[i]>maxCnt1) { | |
1511 | best3=best2; | |
1512 | best2=best1; | |
1513 | maxCnt1=fcCnts[i]; | |
1514 | best1=i; | |
1515 | } else if(fcCnts[i]>fcCnts[best2]){ | |
1516 | best3=best2; | |
1517 | best2=i; | |
1518 | } else if(fcCnts[i]>fcCnts[best3]){ | |
1519 | best3=i; | |
1520 | } | |
1521 | if (g_debugMode==2) prnt("DEBUG countfc: FC %u, Cnt %u, best fc: %u, best2 fc: %u",fcLens[i],fcCnts[i],fcLens[best1],fcLens[best2]); | |
1522 | } | |
1523 | if (fcLens[best1]==0) return 0; | |
1524 | uint8_t fcH=0, fcL=0; | |
1525 | if (fcLens[best1]>fcLens[best2]){ | |
1526 | fcH=fcLens[best1]; | |
1527 | fcL=fcLens[best2]; | |
1528 | } else{ | |
1529 | fcH=fcLens[best2]; | |
1530 | fcL=fcLens[best1]; | |
1531 | } | |
1532 | if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) { | |
1533 | if (g_debugMode==2) prnt("DEBUG countfc: fc is too large: %u > %u. Not psk or fsk",(size-180)/fcH/3,fcCnts[best1]+fcCnts[best2]); | |
1534 | return 0; //lots of waves not psk or fsk | |
1535 | } | |
1536 | // TODO: take top 3 answers and compare to known Field clocks to get top 2 | |
1537 | ||
1538 | uint16_t fcs = (((uint16_t)fcH)<<8) | fcL; | |
1539 | if (fskAdj) return fcs; | |
1540 | return fcLens[best1]; | |
1541 | } | |
1542 | ||
1543 | //by marshmellow - demodulate PSK1 wave | |
1544 | //uses wave lengths (# Samples) | |
1545 | int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) { | |
1546 | if (size == 0) return -1; | |
1547 | uint16_t loopCnt = 4096; //don't need to loop through entire array... | |
1548 | if (*size<loopCnt) loopCnt = *size; | |
1549 | ||
1550 | size_t numBits=0; | |
1551 | uint8_t curPhase = *invert; | |
1552 | size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0; | |
1553 | uint16_t fc=0, fullWaveLen=0, tol=1; | |
1554 | uint16_t errCnt=0, waveLenCnt=0, errCnt2=0; | |
1555 | fc = countFC(dest, *size, 1); | |
1556 | uint8_t fc2 = fc >> 8; | |
1557 | if (fc2 == 10) return -1; //fsk found - quit | |
1558 | fc = fc & 0xFF; | |
1559 | if (fc!=2 && fc!=4 && fc!=8) return -1; | |
1560 | //PrintAndLog("DEBUG: FC: %d",fc); | |
1561 | *clock = DetectPSKClock(dest, *size, *clock); | |
1562 | if (*clock == 0) return -1; | |
1563 | ||
1564 | //find start of modulating data in trace | |
1565 | uint8_t threshold_value = 123; //-5 | |
1566 | i = findModStart(dest, *size, threshold_value, fc); | |
1567 | ||
1568 | //find first phase shift | |
1569 | int avgWaveVal=0, lastAvgWaveVal=0; | |
1570 | waveStart = i; | |
1571 | for (; i<loopCnt; i++) { | |
1572 | // find peak | |
1573 | if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1574 | waveEnd = i+1; | |
1575 | if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart); | |
1576 | waveLenCnt = waveEnd-waveStart; | |
1577 | if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack | |
1578 | lastAvgWaveVal = avgWaveVal/(waveLenCnt); | |
1579 | firstFullWave = waveStart; | |
1580 | fullWaveLen=waveLenCnt; | |
1581 | //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting) | |
1582 | if (lastAvgWaveVal > threshold_value) curPhase ^= 1; | |
1583 | break; | |
1584 | } | |
1585 | ||
1586 | waveStart = i+1; | |
1587 | avgWaveVal = 0; | |
1588 | } | |
1589 | avgWaveVal += dest[i+2]; | |
1590 | } | |
1591 | if (firstFullWave == 0) { | |
1592 | // no phase shift detected - could be all 1's or 0's - doesn't matter where we start | |
1593 | // so skip a little to ensure we are past any Start Signal | |
1594 | firstFullWave = 160; | |
1595 | memset(dest, curPhase, firstFullWave / *clock); | |
1596 | } else { | |
1597 | memset(dest, curPhase^1, firstFullWave / *clock); | |
1598 | } | |
1599 | //advance bits | |
1600 | numBits += (firstFullWave / *clock); | |
1601 | *startIdx = firstFullWave - (*clock * numBits)+2; | |
1602 | //set start of wave as clock align | |
1603 | lastClkBit = firstFullWave; | |
1604 | if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx); | |
1605 | if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc); | |
1606 | waveStart = 0; | |
1607 | dest[numBits++] = curPhase; //set first read bit | |
1608 | for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){ | |
1609 | //top edge of wave = start of new wave | |
1610 | if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){ | |
1611 | if (waveStart == 0) { | |
1612 | waveStart = i+1; | |
1613 | waveLenCnt = 0; | |
1614 | avgWaveVal = dest[i+1]; | |
1615 | } else { //waveEnd | |
1616 | waveEnd = i+1; | |
1617 | waveLenCnt = waveEnd-waveStart; | |
1618 | lastAvgWaveVal = avgWaveVal/waveLenCnt; | |
1619 | if (waveLenCnt > fc){ | |
1620 | //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal); | |
1621 | //this wave is a phase shift | |
1622 | //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc); | |
1623 | if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit | |
1624 | curPhase ^= 1; | |
1625 | dest[numBits++] = curPhase; | |
1626 | lastClkBit += *clock; | |
1627 | } else if (i < lastClkBit+10+fc){ | |
1628 | //noise after a phase shift - ignore | |
1629 | } else { //phase shift before supposed to based on clock | |
1630 | errCnt++; | |
1631 | dest[numBits++] = 7; | |
1632 | } | |
1633 | } else if (i+1 > lastClkBit + *clock + tol + fc){ | |
1634 | lastClkBit += *clock; //no phase shift but clock bit | |
1635 | dest[numBits++] = curPhase; | |
1636 | } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often) | |
1637 | errCnt2++; | |
1638 | if(errCnt2 > 101) return errCnt2; | |
1639 | } | |
1640 | avgWaveVal = 0; | |
1641 | waveStart = i+1; | |
1642 | } | |
1643 | } | |
1644 | avgWaveVal += dest[i+1]; | |
1645 | } | |
1646 | *size = numBits; | |
1647 | return errCnt; | |
1648 | } | |
1649 | ||
1650 | int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) { | |
1651 | int startIdx = 0; | |
1652 | return pskRawDemod_ext(dest, size, clock, invert, &startIdx); | |
1653 | } | |
1654 | ||
1655 | //by marshmellow | |
1656 | //attempt to identify a Sequence Terminator in ASK modulated raw wave | |
1657 | bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) { | |
1658 | size_t bufsize = *size; | |
1659 | //need to loop through all samples and identify our clock, look for the ST pattern | |
1660 | uint8_t fndClk[] = {8,16,32,40,50,64,128}; | |
1661 | int clk = 0; | |
1662 | int tol = 0; | |
1663 | int i, j, skip, start, end, low, high, minClk, waveStart; | |
1664 | bool complete = false; | |
1665 | int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured | |
1666 | int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed... | |
1667 | size_t testsize = (bufsize < 512) ? bufsize : 512; | |
1668 | int phaseoff = 0; | |
1669 | high = low = 128; | |
1670 | memset(tmpbuff, 0, sizeof(tmpbuff)); | |
1671 | ||
1672 | if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) { | |
1673 | if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting"); | |
1674 | return false; //just noise | |
1675 | } | |
1676 | i = 0; | |
1677 | j = 0; | |
1678 | minClk = 255; | |
1679 | // get to first full low to prime loop and skip incomplete first pulse | |
1680 | while ((buffer[i] < high) && (i < bufsize)) | |
1681 | ++i; | |
1682 | while ((buffer[i] > low) && (i < bufsize)) | |
1683 | ++i; | |
1684 | skip = i; | |
1685 | ||
1686 | // populate tmpbuff buffer with pulse lengths | |
1687 | while (i < bufsize) { | |
1688 | // measure from low to low | |
1689 | while ((buffer[i] > low) && (i < bufsize)) | |
1690 | ++i; | |
1691 | start= i; | |
1692 | while ((buffer[i] < high) && (i < bufsize)) | |
1693 | ++i; | |
1694 | //first high point for this wave | |
1695 | waveStart = i; | |
1696 | while ((buffer[i] > low) && (i < bufsize)) | |
1697 | ++i; | |
1698 | if (j >= (bufsize/32)) { | |
1699 | break; | |
1700 | } | |
1701 | waveLen[j] = i - waveStart; //first high to first low | |
1702 | tmpbuff[j++] = i - start; | |
1703 | if (i-start < minClk && i < bufsize) { | |
1704 | minClk = i - start; | |
1705 | } | |
1706 | } | |
1707 | // set clock - might be able to get this externally and remove this work... | |
1708 | if (!clk) { | |
1709 | for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) { | |
1710 | tol = fndClk[clkCnt]/8; | |
1711 | if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) { | |
1712 | clk=fndClk[clkCnt]; | |
1713 | break; | |
1714 | } | |
1715 | } | |
1716 | // clock not found - ERROR | |
1717 | if (!clk) { | |
1718 | if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting"); | |
1719 | return false; | |
1720 | } | |
1721 | } else tol = clk/8; | |
1722 | ||
1723 | *foundclock = clk; | |
1724 | ||
1725 | // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2) | |
1726 | start = -1; | |
1727 | for (i = 0; i < j - 4; ++i) { | |
1728 | skip += tmpbuff[i]; | |
1729 | if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior | |
1730 | if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 | |
1731 | if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave | |
1732 | if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit | |
1733 | start = i + 3; | |
1734 | break; | |
1735 | } | |
1736 | } | |
1737 | } | |
1738 | } | |
1739 | } | |
1740 | // first ST not found - ERROR | |
1741 | if (start < 0) { | |
1742 | if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting"); | |
1743 | return false; | |
1744 | } else { | |
1745 | if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j); | |
1746 | } | |
1747 | if (waveLen[i+2] > clk*1+tol) | |
1748 | phaseoff = 0; | |
1749 | else | |
1750 | phaseoff = clk/2; | |
1751 | ||
1752 | // skip over the remainder of ST | |
1753 | skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point | |
1754 | ||
1755 | // now do it again to find the end | |
1756 | end = skip; | |
1757 | for (i += 3; i < j - 4; ++i) { | |
1758 | end += tmpbuff[i]; | |
1759 | if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior | |
1760 | if (tmpbuff[i+1] >= clk*2-tol && tmpbuff[i+1] <= clk*2+tol && waveLen[i+1] > clk*3/2-tol) { //2 clocks and wave size is 1 1/2 | |
1761 | if (tmpbuff[i+2] >= (clk*3)/2-tol && tmpbuff[i+2] <= clk*2+tol && waveLen[i+2] > clk-tol) { //1 1/2 to 2 clocks and at least one full clock wave | |
1762 | if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit | |
1763 | complete = true; | |
1764 | break; | |
1765 | } | |
1766 | } | |
1767 | } | |
1768 | } | |
1769 | } | |
1770 | end -= phaseoff; | |
1771 | //didn't find second ST - ERROR | |
1772 | if (!complete) { | |
1773 | if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting"); | |
1774 | return false; | |
1775 | } | |
1776 | if (g_debugMode==2) prnt("DEBUG STT: start of data: %d end of data: %d, datalen: %d, clk: %d, bits: %d, phaseoff: %d", skip, end, end-skip, clk, (end-skip)/clk, phaseoff); | |
1777 | //now begin to trim out ST so we can use normal demod cmds | |
1778 | start = skip; | |
1779 | size_t datalen = end - start; | |
1780 | // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock | |
1781 | if ( clk - (datalen % clk) <= clk/8) { | |
1782 | // padd the amount off - could be problematic... but shouldn't happen often | |
1783 | datalen += clk - (datalen % clk); | |
1784 | } else if ( (datalen % clk) <= clk/8 ) { | |
1785 | // padd the amount off - could be problematic... but shouldn't happen often | |
1786 | datalen -= datalen % clk; | |
1787 | } else { | |
1788 | if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk); | |
1789 | return false; | |
1790 | } | |
1791 | // if datalen is less than one t55xx block - ERROR | |
1792 | if (datalen/clk < 8*4) { | |
1793 | if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting"); | |
1794 | return false; | |
1795 | } | |
1796 | size_t dataloc = start; | |
1797 | if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) { | |
1798 | //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start | |
1799 | for ( i=0; i <= (clk/8); ++i ) { | |
1800 | if ( buffer[dataloc - (clk*4) - i] <= low ) { | |
1801 | dataloc -= i; | |
1802 | break; | |
1803 | } | |
1804 | } | |
1805 | } | |
1806 | ||
1807 | size_t newloc = 0; | |
1808 | i=0; | |
1809 | if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen); | |
1810 | bool firstrun = true; | |
1811 | // warning - overwriting buffer given with raw wave data with ST removed... | |
1812 | while ( dataloc < bufsize-(clk/2) ) { | |
1813 | //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part) | |
1814 | if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) { | |
1815 | for(i=0; i < clk/2-tol; ++i) { | |
1816 | buffer[dataloc+i] = high+5; | |
1817 | } | |
1818 | } //test for single sample outlier (high between two lows) in the case of very strong waves | |
1819 | if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) { | |
1820 | buffer[dataloc] = buffer[dataloc+2]; | |
1821 | buffer[dataloc+1] = buffer[dataloc+2]; | |
1822 | } | |
1823 | if (firstrun) { | |
1824 | *stend = dataloc; | |
1825 | *ststart = dataloc-(clk*4); | |
1826 | firstrun=false; | |
1827 | } | |
1828 | for (i=0; i<datalen; ++i) { | |
1829 | if (i+newloc < bufsize) { | |
1830 | if (i+newloc < dataloc) | |
1831 | buffer[i+newloc] = buffer[dataloc]; | |
1832 | ||
1833 | dataloc++; | |
1834 | } | |
1835 | } | |
1836 | newloc += i; | |
1837 | //skip next ST - we just assume it will be there from now on... | |
1838 | if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4)); | |
1839 | dataloc += clk*4; | |
1840 | } | |
1841 | *size = newloc; | |
1842 | return true; | |
1843 | } | |
1844 | ||
1845 | bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) { | |
1846 | size_t ststart = 0, stend = 0; | |
1847 | return DetectST_ext(buffer, size, foundclock, &ststart, &stend); | |
1848 | } | |
1849 | ||
1850 | // by iceman | |
1851 | // find Visa2000 preamble in already demoded data | |
1852 | int Visa2kDemod_AM(uint8_t *dest, size_t *size) { | |
1853 | if (*size < 96) return -1; //make sure buffer has data | |
1854 | size_t startIdx = 0; | |
1855 | uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0}; | |
1856 | if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0) | |
1857 | return -2; //preamble not found | |
1858 | if (*size != 96) return -3; //wrong demoded size | |
1859 | //return start position | |
1860 | return (int)startIdx; | |
1861 | } |