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FIX: @marshmellow42 's ST detection fix.
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eb191de6 1//-----------------------------------------------------------------------------
ba1a299c 2// Copyright (C) 2014
eb191de6 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//-----------------------------------------------------------------------------
1e090a61 8// Low frequency demod/decode commands
eb191de6 9//-----------------------------------------------------------------------------
eb191de6 10#include "lfdemod.h"
6426f6ba 11
a126332a 12//un_comment to allow debug print calls when used not on device
6426f6ba 13void dummy(char *fmt, ...){}
14
e977fb0d 15
6426f6ba 16#ifndef ON_DEVICE
e977fb0d 17# include "ui.h"
18# include "cmdparser.h"
19# include "cmddata.h"
20# define prnt PrintAndLog
6426f6ba 21#else
a126332a 22 uint8_t g_debugMode=0;
e977fb0d 23# define prnt dummy
6426f6ba 24#endif
6426f6ba 25
2dcf60f3 26//test samples are not just noise
27uint8_t justNoise(uint8_t *bits, size_t size) {
28 #define THRESHOLD 123
29 uint8_t val = 1;
30 for(size_t idx=0; idx < size && val ;idx++)
31 val = bits[idx] < THRESHOLD;
32 return val;
a1d17964 33}
34
1e090a61 35//by marshmellow
872e3d4d 36//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
1e090a61 37int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
38{
39 *high=0;
40 *low=255;
41 // get high and low thresholds
2eec55c8 42 for (size_t i=0; i < size; i++){
1e090a61 43 if (BitStream[i] > *high) *high = BitStream[i];
44 if (BitStream[i] < *low) *low = BitStream[i];
45 }
46 if (*high < 123) return -1; // just noise
75cbbe9a 47 *high = ((*high-128)*fuzzHi + 12800)/100;
48 *low = ((*low-128)*fuzzLo + 12800)/100;
1e090a61 49 return 1;
50}
51
a1d17964 52// by marshmellow
53// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
54// returns 1 if passed
55uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
56{
57 uint8_t ans = 0;
58 for (uint8_t i = 0; i < bitLen; i++){
59 ans ^= ((bits >> i) & 1);
60 }
4ac9f078 61 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
a1d17964 62 return (ans == pType);
63}
64
a126332a 65//by marshmellow
66// takes a array of binary values, start position, length of bits per parity (includes parity bit),
c728b2b4 67// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
a126332a 68size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
69{
70 uint32_t parityWd = 0;
71 size_t j = 0, bitCnt = 0;
c08c796e 72 for (int word = 0; word < (bLen); word += pLen){
a126332a 73 for (int bit=0; bit < pLen; bit++){
74 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
75 BitStream[j++] = (BitStream[startIdx+word+bit]);
76 }
5215a874 77 if (word+pLen > bLen) break;
4ac9f078 78
a126332a 79 j--; // overwrite parity with next data
80 // if parity fails then return 0
c728b2b4 81 switch (pType) {
11dee3d5 82 case 3: if (BitStream[j]==1) { return 0; } break; //should be 0 spacer bit
83 case 2: if (BitStream[j]==0) { return 0; } break; //should be 1 spacer bit
3c654208 84 default: if (parityTest(parityWd, pLen, pType) == 0) { return 0; } break; //test parity
a126332a 85 }
c08c796e 86 bitCnt += (pLen-1);
a126332a 87 parityWd = 0;
88 }
89 // if we got here then all the parities passed
90 //return ID start index and size
91 return bitCnt;
92}
93
94// by marshmellow
95// takes a array of binary values, length of bits per parity (includes parity bit),
0d2c5909 96// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
c728b2b4 97// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
a126332a 98size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
99{
100 uint32_t parityWd = 0;
101 size_t j = 0, bitCnt = 0;
102 for (int word = 0; word < sourceLen; word+=pLen-1) {
103 for (int bit=0; bit < pLen-1; bit++){
104 parityWd = (parityWd << 1) | BitSource[word+bit];
105 dest[j++] = (BitSource[word+bit]);
106 }
0d2c5909 107
a126332a 108 // if parity fails then return 0
0d2c5909 109 switch (pType) {
110 case 3: dest[j++]=0; break; // marker bit which should be a 0
111 case 2: dest[j++]=1; break; // marker bit which should be a 1
112 default:
113 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
114 break;
a126332a 115 }
116 bitCnt += pLen;
117 parityWd = 0;
118 }
119 // if we got here then all the parities passed
120 //return ID start index and size
121 return bitCnt;
122}
123
124uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
125{
126 uint32_t num = 0;
0d2c5909 127 for(int i = 0 ; i < numbits ; i++) {
a126332a 128 num = (num << 1) | (*src);
129 src++;
130 }
131 return num;
132}
133
134//least significant bit first
135uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
136{
137 uint32_t num = 0;
6b6815bc 138 for(int i = 0 ; i < numbits ; i++) {
a126332a 139 num = (num << 1) | *(src + (numbits-(i+1)));
140 }
141 return num;
142}
143
8ad1e731 144//by marshmellow
145// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
146bool preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx){
147 return preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false);
148}
a1d17964 149//by marshmellow
2147c307 150//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
8ad1e731 151// param @findone: look for a repeating preamble or only the first.
152// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
153bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone)
a1d17964 154{
5735cfa5 155 // Sanity check. If preamble length is bigger than bitstream length.
8ad1e731 156 if ( *size <= pLen ) return false;
5735cfa5 157
56d0fb8e 158 uint8_t foundCnt = 0;
159 for (int idx = 0; idx < *size - pLen; idx++){
e0165dcf 160 if (memcmp(BitStream+idx, preamble, pLen) == 0){
5215a874 161 if (g_debugMode) prnt("DEBUG: preamble found at %i", idx);
e0165dcf 162 //first index found
163 foundCnt++;
164 if (foundCnt == 1){
165 *startIdx = idx;
8ad1e731 166 if (findone) return true;
e0165dcf 167 }
168 if (foundCnt == 2){
169 *size = idx - *startIdx;
8ad1e731 170 return true;
e0165dcf 171 }
172 }
173 }
8ad1e731 174 return false;
175}
176
177// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
178size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
179 size_t i = 0;
180 size_t waveSizeCnt = 0;
181 uint8_t thresholdCnt = 0;
182 bool isAboveThreshold = dest[i++] >= threshold_value;
183 for (; i < size-20; i++ ) {
184 if(dest[i] < threshold_value && isAboveThreshold) {
185 thresholdCnt++;
186 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
187 isAboveThreshold = false;
188 waveSizeCnt = 0;
189 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
190 thresholdCnt++;
191 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
192 isAboveThreshold = true;
193 waveSizeCnt = 0;
194 } else {
195 waveSizeCnt++;
196 }
197 if (thresholdCnt > 10) break;
198 }
199 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
200 return i;
a1d17964 201}
202
2147c307 203//by marshmellow
204//takes 1s and 0s and searches for EM410x format - output EM ID
8ad1e731 205// actually, no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
a8fd088d 206int Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
2147c307 207{
5215a874 208 // sanity check
a8fd088d 209 if (BitStream[1] > 1) return -1;
8ad1e731 210
5215a874 211 uint8_t fmtlen;
e0165dcf 212 *startIdx = 0;
8ad1e731 213
214 // preamble 0111111111
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 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx))
a8fd088d 218 return -2;
219 if (*size < 64) return -3;
8ad1e731 220
5215a874 221 fmtlen = (*size == 110) ? 22 : 10;
8ad1e731 222
5215a874 223 //skip last 4bit parity row for simplicity
224 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, fmtlen * 5);
225
226 switch (*size) {
227 case 40: {
228 // std em410x format
229 *hi = 0;
230 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
231 break;
232 }
233 case 88: {
234 // long em format
235 *hi = (bytebits_to_byte(BitStream, 24));
236 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
237 break;
238 }
a8fd088d 239 default: return -4;
e0165dcf 240 }
8ad1e731 241 return 1;
2147c307 242}
243
fef74fdc 244//by marshmellow
245//demodulates strong heavily clipped samples
4eabb8ad 246//RETURN: num of errors. if 0, is ok.
23f0a7d8 247int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
248{
249 size_t bitCnt=0, smplCnt=0, errCnt=0;
250 uint8_t waveHigh = 0;
23f0a7d8 251 for (size_t i=0; i < *size; i++){
252 if (BinStream[i] >= high && waveHigh){
253 smplCnt++;
254 } else if (BinStream[i] <= low && !waveHigh){
255 smplCnt++;
256 } else { //transition
257 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
81e82dfe 258
23f0a7d8 259 if (smplCnt > clk-(clk/4)-1) { //full clock
a38f5a07 260 if (smplCnt > clk + (clk/4)+1) { //too many samples
23f0a7d8 261 errCnt++;
05164399 262 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
81e82dfe 263 BinStream[bitCnt++] = 7;
23f0a7d8 264 } else if (waveHigh) {
265 BinStream[bitCnt++] = invert;
266 BinStream[bitCnt++] = invert;
267 } else if (!waveHigh) {
268 BinStream[bitCnt++] = invert ^ 1;
269 BinStream[bitCnt++] = invert ^ 1;
270 }
271 waveHigh ^= 1;
272 smplCnt = 0;
273 } else if (smplCnt > (clk/2) - (clk/4)-1) {
274 if (waveHigh) {
275 BinStream[bitCnt++] = invert;
276 } else if (!waveHigh) {
277 BinStream[bitCnt++] = invert ^ 1;
278 }
279 waveHigh ^= 1;
280 smplCnt = 0;
281 } else if (!bitCnt) {
282 //first bit
283 waveHigh = (BinStream[i] >= high);
284 smplCnt = 1;
285 } else {
286 smplCnt++;
287 //transition bit oops
288 }
289 } else { //haven't hit new high or new low yet
290 smplCnt++;
291 }
292 }
293 }
294 *size = bitCnt;
295 return errCnt;
296}
297
eb191de6 298//by marshmellow
fef74fdc 299void askAmp(uint8_t *BitStream, size_t size)
300{
9686a8d4 301 uint8_t last = 128;
302 for(size_t i = 1; i < size; ++i){
303 if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
304 last = 255;
305 else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
306 last = 0;
307
308 BitStream[i] = last;
fef74fdc 309 }
fef74fdc 310}
311
312//by marshmellow
313//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
314int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
eb191de6 315{
fef74fdc 316 if (*size==0) return -1;
6e984446 317 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
bd09006a 318
2eec55c8 319 if (*clk==0 || start < 0) return -3;
fef74fdc 320 if (*invert != 1) *invert = 0;
321 if (amp==1) askAmp(BinStream, *size);
a38f5a07 322 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
fef74fdc 323
2eec55c8 324 uint8_t initLoopMax = 255;
325 if (initLoopMax > *size) initLoopMax = *size;
ba1a299c 326 // Detect high and lows
fef74fdc 327 //25% clip in case highs and lows aren't clipped [marshmellow]
2eec55c8 328 int high, low;
fef74fdc 329 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
330 return -2; //just noise
ba1a299c 331
fef74fdc 332 size_t errCnt = 0;
23f0a7d8 333 // if clean clipped waves detected run alternate demod
334 if (DetectCleanAskWave(BinStream, *size, high, low)) {
05164399 335 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
fef74fdc 336 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
337 if (askType) //askman
338 return manrawdecode(BinStream, size, 0);
81e82dfe 339 //askraw
340 return errCnt;
23f0a7d8 341 }
05164399 342 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
23f0a7d8 343
fef74fdc 344 int lastBit; //set first clock check - can go negative
345 size_t i, bitnum = 0; //output counter
346 uint8_t midBit = 0;
2eec55c8 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
fef74fdc 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
05164399 349 size_t MaxBits = 3072; //max bits to collect
6e984446 350 lastBit = start - *clk;
fef74fdc 351
6e984446 352 for (i = start; i < *size; ++i) {
fef74fdc 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) {
05164399 360 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
fef74fdc 361 BinStream[bitnum++]=7;
362 errCnt++;
363 }
364 } else { //in tolerance - looking for peak
365 continue;
366 }
367 midBit = 0;
2eec55c8 368 lastBit += *clk;
fef74fdc 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;
2eec55c8 381 }
382 if (bitnum >= MaxBits) break;
ba1a299c 383 }
2eec55c8 384 *size = bitnum;
6e984446 385 return errCnt;
eb191de6 386}
eb191de6 387//by marshmellow
388//take 10 and 01 and manchester decode
389//run through 2 times and take least errCnt
4eabb8ad 390int manrawdecode(uint8_t *BitStream, size_t *size, uint8_t invert){
391
392 // sanity check
393 if (*size < 16) return -1;
394
5f5b83b7 395 int errCnt = 0, bestErr = 1000;
396 uint16_t bitnum = 0, MaxBits = 512, bestRun = 0;
81e82dfe 397 size_t i, k;
4eabb8ad 398
2767fc02 399 //find correct start position [alignment]
4eabb8ad 400 for (k = 0; k < 2; ++k){
401 for (i = k; i < *size-3; i += 2) {
81e82dfe 402 if (BitStream[i] == BitStream[i+1])
ba1a299c 403 errCnt++;
4eabb8ad 404 }
81e82dfe 405 if (bestErr > errCnt){
406 bestErr = errCnt;
407 bestRun = k;
ba1a299c 408 }
4eabb8ad 409 errCnt = 0;
ba1a299c 410 }
4eabb8ad 411
2767fc02 412 //decode
4eabb8ad 413 for (i = bestRun; i < *size-3; i += 2){
81e82dfe 414 if (BitStream[i] == 1 && (BitStream[i+1] == 0)){
415 BitStream[bitnum++] = invert;
416 } else if ((BitStream[i] == 0) && BitStream[i+1] == 1){
417 BitStream[bitnum++] = invert^1;
23f0a7d8 418 } else {
81e82dfe 419 BitStream[bitnum++] = 7;
ba1a299c 420 }
4eabb8ad 421 if (bitnum > MaxBits) break;
ba1a299c 422 }
4eabb8ad 423 *size = bitnum;
2eec55c8 424 return bestErr;
f822a063 425}
426
1d0ccbe0 427uint32_t manchesterEncode2Bytes(uint16_t datain) {
428 uint32_t output = 0;
429 uint8_t curBit = 0;
430 for (uint8_t i=0; i<16; i++) {
431 curBit = (datain >> (15-i) & 1);
432 output |= (1<<(((15-i)*2)+curBit));
433 }
434 return output;
435}
436
fef74fdc 437//by marshmellow
438//encode binary data into binary manchester
439int ManchesterEncode(uint8_t *BitStream, size_t size)
440{
441 size_t modIdx=20000, i=0;
442 if (size>modIdx) return -1;
443 for (size_t idx=0; idx < size; idx++){
444 BitStream[idx+modIdx++] = BitStream[idx];
445 BitStream[idx+modIdx++] = BitStream[idx]^1;
446 }
447 for (; i<(size*2); i++){
448 BitStream[i] = BitStream[i+20000];
449 }
450 return i;
451}
452
f822a063 453//by marshmellow
2147c307 454//take 01 or 10 = 1 and 11 or 00 = 0
455//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
13d77ef9 456//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1e090a61 457int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
f822a063 458{
2eec55c8 459 uint16_t bitnum = 0;
460 uint16_t errCnt = 0;
461 size_t i = offset;
2147c307 462 uint16_t MaxBits=512;
463 //if not enough samples - error
464 if (*size < 51) return -1;
465 //check for phase change faults - skip one sample if faulty
466 uint8_t offsetA = 1, offsetB = 1;
467 for (; i<48; i+=2){
468 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
469 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
470 }
471 if (!offsetA && offsetB) offset++;
472 for (i=offset; i<*size-3; i+=2){
473 //check for phase error
13d77ef9 474 if (BitStream[i+1]==BitStream[i+2]) {
2767fc02 475 BitStream[bitnum++]=7;
2147c307 476 errCnt++;
477 }
ba1a299c 478 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1e090a61 479 BitStream[bitnum++]=1^invert;
ba1a299c 480 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1e090a61 481 BitStream[bitnum++]=invert;
ba1a299c 482 } else {
2767fc02 483 BitStream[bitnum++]=7;
ba1a299c 484 errCnt++;
485 }
6de43508 486 if(bitnum>MaxBits) break;
ba1a299c 487 }
488 *size=bitnum;
489 return errCnt;
eb191de6 490}
491
fef74fdc 492// by marshmellow
11081e04 493// demod gProxIIDemod
494// error returns as -x
495// success returns start position in BitStream
496// BitStream must contain previously askrawdemod and biphasedemoded data
497int gProxII_Demod(uint8_t BitStream[], size_t *size)
498{
499 size_t startIdx=0;
500 uint8_t preamble[] = {1,1,1,1,1,0};
501
8ad1e731 502 if (!preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx))
503 return -3; //preamble not found
504
11081e04 505 if (*size != 96) return -2; //should have found 96 bits
8ad1e731 506
11081e04 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 }
7fa7e812 513 return -5; //spacer bits not found - not a valid gproxII
11081e04 514}
515
7fa7e812 516//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
f822a063 517size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
eb191de6 518{
2eec55c8 519 size_t last_transition = 0;
520 size_t idx = 1;
ba1a299c 521 if (fchigh==0) fchigh=10;
522 if (fclow==0) fclow=8;
84871873 523 //set the threshold close to 0 (graph) or 128 std to avoid static
524 uint8_t threshold_value = 123;
ac2df346 525 size_t preLastSample = 0;
526 size_t LastSample = 0;
527 size_t currSample = 0;
4ac9f078 528 if ( size < 1024 ) return 0; // not enough samples
529
8ad1e731 530 //find start of modulating data in trace
531 idx = findModStart(dest, size, threshold_value, fchigh);
ba1a299c 532
533 // Need to threshold first sample
4ac9f078 534 if(dest[idx] < threshold_value) dest[0] = 0;
ba1a299c 535 else dest[0] = 1;
4ac9f078 536 idx++;
ba1a299c 537
538 size_t numBits = 0;
539 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
cd0bed3c 540 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
ba1a299c 541 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
7fa7e812 542 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
4ac9f078 543 for(; idx < size-20; idx++) {
ba1a299c 544 // threshold current value
545
546 if (dest[idx] < threshold_value) dest[idx] = 0;
547 else dest[idx] = 1;
548
549 // Check for 0->1 transition
7fa7e812 550 if (dest[idx-1] < dest[idx]) {
ac2df346 551 preLastSample = LastSample;
552 LastSample = currSample;
553 currSample = idx-last_transition;
6426f6ba 554 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
ba1a299c 555 //do nothing with extra garbage
7fa7e812 556 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
557 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
4ac9f078 558 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
7fa7e812 559 dest[numBits-1]=1;
ac2df346 560 }
2eec55c8 561 dest[numBits++]=1;
ac2df346 562
4ac9f078 563 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
564 //do nothing with beginning garbage and reset.. should be rare..
565 numBits = 0;
7fa7e812 566 } 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)
ac2df346 567 dest[numBits++]=1;
7fa7e812 568 } else { //9+ = 10 sample waves (or 6+ = 7)
2eec55c8 569 dest[numBits++]=0;
ba1a299c 570 }
571 last_transition = idx;
ba1a299c 572 }
573 }
574 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
eb191de6 575}
576
ba1a299c 577//translate 11111100000 to 10
7fa7e812 578//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
2eec55c8 579size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
e0165dcf 580 uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 581{
ba1a299c 582 uint8_t lastval=dest[0];
2eec55c8 583 size_t idx=0;
ba1a299c 584 size_t numBits=0;
585 uint32_t n=1;
ba1a299c 586 for( idx=1; idx < size; idx++) {
13d77ef9 587 n++;
a38f5a07 588 if (dest[idx]==lastval) continue; //skip until we hit a transition
2eec55c8 589
7fa7e812 590 //find out how many bits (n) we collected
ba1a299c 591 //if lastval was 1, we have a 1->0 crossing
13d77ef9 592 if (dest[idx-1]==1) {
75cbbe9a 593 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 594 } else {// 0->1 crossing
75cbbe9a 595 n = (n * fchigh + rfLen/2) / rfLen;
ba1a299c 596 }
597 if (n == 0) n = 1;
598
7fa7e812 599 //add to our destination the bits we collected
2eec55c8 600 memset(dest+numBits, dest[idx-1]^invert , n);
601 numBits += n;
ba1a299c 602 n=0;
603 lastval=dest[idx];
604 }//end for
13d77ef9 605 // if valid extra bits at the end were all the same frequency - add them in
75cbbe9a 606 if (n > rfLen/fchigh) {
13d77ef9 607 if (dest[idx-2]==1) {
75cbbe9a 608 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 609 } else {
75cbbe9a 610 n = (n * fchigh + rfLen/2) / rfLen;
13d77ef9 611 }
2eec55c8 612 memset(dest+numBits, dest[idx-1]^invert , n);
13d77ef9 613 numBits += n;
614 }
ba1a299c 615 return numBits;
eb191de6 616}
6426f6ba 617
eb191de6 618//by marshmellow (from holiman's base)
619// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
f822a063 620int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 621{
ba1a299c 622 // FSK demodulator
623 size = fsk_wave_demod(dest, size, fchigh, fclow);
2eec55c8 624 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
ba1a299c 625 return size;
eb191de6 626}
a1d17964 627
eb191de6 628// loop to get raw HID waveform then FSK demodulate the TAG ID from it
ec75f5c1 629int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
eb191de6 630{
e0165dcf 631 if (justNoise(dest, *size)) return -1;
632
337f7036 633 size_t numStart=0, size2 = *size, startIdx=0;
e0165dcf 634 // FSK demodulator
635 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
2eec55c8 636 if (*size < 96*2) return -2;
e0165dcf 637 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
638 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
8ad1e731 639 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
640 return -3; //preamble not found
e0165dcf 641
642 numStart = startIdx + sizeof(preamble);
643 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
644 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
645 if (dest[idx] == dest[idx+1]){
646 return -4; //not manchester data
647 }
648 *hi2 = (*hi2<<1)|(*hi>>31);
649 *hi = (*hi<<1)|(*lo>>31);
650 //Then, shift in a 0 or one into low
81b7e894 651 *lo <<= 1;
e0165dcf 652 if (dest[idx] && !dest[idx+1]) // 1 0
81b7e894 653 *lo |= 1;
e0165dcf 654 else // 0 1
81b7e894 655 *lo |= 0;
e0165dcf 656 }
657 return (int)startIdx;
eb191de6 658}
659
ec75f5c1 660// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
a1d17964 661int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
ec75f5c1 662{
a1d17964 663 if (justNoise(dest, *size)) return -1;
664
337f7036 665 size_t numStart=0, size2 = *size, startIdx=0;
ec75f5c1 666 // FSK demodulator
a1d17964 667 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
668 if (*size < 96) return -2;
ec75f5c1 669
a1d17964 670 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
671 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
8ad1e731 672 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
673 return -3; //preamble not found
a1d17964 674
675 numStart = startIdx + sizeof(preamble);
676 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
677 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
678 if (dest[idx] == dest[idx+1])
679 return -4; //not manchester data
680 *hi2 = (*hi2<<1)|(*hi>>31);
681 *hi = (*hi<<1)|(*lo>>31);
682 //Then, shift in a 0 or one into low
683 if (dest[idx] && !dest[idx+1]) // 1 0
684 *lo=(*lo<<1)|1;
685 else // 0 1
686 *lo=(*lo<<1)|0;
ec75f5c1 687 }
a1d17964 688 return (int)startIdx;
ec75f5c1 689}
690
eb191de6 691int IOdemodFSK(uint8_t *dest, size_t size)
692{
a1d17964 693 if (justNoise(dest, size)) return -1;
ba1a299c 694 //make sure buffer has data
a1d17964 695 if (size < 66*64) return -2;
ba1a299c 696 // FSK demodulator
a1d17964 697 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
698 if (size < 65) return -3; //did we get a good demod?
ba1a299c 699 //Index map
700 //0 10 20 30 40 50 60
701 //| | | | | | |
702 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
703 //-----------------------------------------------------------------------------
704 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
705 //
706 //XSF(version)facility:codeone+codetwo
707 //Handle the data
a1d17964 708 size_t startIdx = 0;
709 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
8ad1e731 710 if (! preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx))
711 return -4; //preamble not found
eb191de6 712
a1d17964 713 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
714 //confirmed proper separator bits found
715 //return start position
716 return (int) startIdx;
1e090a61 717 }
a1d17964 718 return -5;
1e090a61 719}
720
70459879 721// by marshmellow
722// find viking preamble 0xF200 in already demoded data
723int VikingDemod_AM(uint8_t *dest, size_t *size) {
70459879 724 //make sure buffer has data
725 if (*size < 64*2) return -2;
70459879 726 size_t startIdx = 0;
727 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};
8ad1e731 728 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
729 return -4; //preamble not found
730
c0afa86f 731 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^
732 bytebits_to_byte(dest+startIdx+8,8) ^
733 bytebits_to_byte(dest+startIdx+16,8) ^
734 bytebits_to_byte(dest+startIdx+24,8) ^
735 bytebits_to_byte(dest+startIdx+32,8) ^
736 bytebits_to_byte(dest+startIdx+40,8) ^
737 bytebits_to_byte(dest+startIdx+48,8) ^
738 bytebits_to_byte(dest+startIdx+56,8);
739 if ( checkCalc != 0xA8 ) return -5;
57c7b44b 740 if (*size != 64) return -6;
70459879 741 //return start position
deba67ab 742 return (int)startIdx;
70459879 743}
744
5daad826 745// by iceman
746// find Visa2000 preamble in already demoded data
747int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
371a40bf 748 if (*size < 96) return -1; //make sure buffer has data
5daad826 749 size_t startIdx = 0;
750 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};
8ad1e731 751 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
752 return -2; //preamble not found
5daad826 753 if (*size != 96) return -3; //wrong demoded size
754 //return start position
deba67ab 755 return (int)startIdx;
5daad826 756}
207fc33a 757// by iceman
758// find Noralsy preamble in already demoded data
759int NoralsyDemod_AM(uint8_t *dest, size_t *size) {
7d269265 760 if (*size < 96) return -1; //make sure buffer has data
207fc33a 761 size_t startIdx = 0;
762 uint8_t preamble[] = {1,0,1,1,1,0,1,1,0,0,0,0};
8ad1e731 763 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
764 return -2; //preamble not found
207fc33a 765 if (*size != 96) return -3; //wrong demoded size
766 //return start position
deba67ab 767 return (int)startIdx;
207fc33a 768}
4469412e 769// find presco preamble 0x10D in already demoded data
770int PrescoDemod(uint8_t *dest, size_t *size) {
d48175d4 771 if (*size < 128*2) return -1; //make sure buffer has data
4469412e 772 size_t startIdx = 0;
d48175d4 773 uint8_t preamble[] = {0,0,0,1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
8ad1e731 774 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
775 return -2; //preamble not found
d48175d4 776 if (*size != 128) return -3; //wrong demoded size
4469412e 777 //return start position
deba67ab 778 return (int)startIdx;
4469412e 779}
780
615f21dd 781// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
0df669a2 782// BitStream must contain previously askrawdemod and biphasedemoded data
deba67ab 783int FDXBdemodBI(uint8_t *dest, size_t *size) {
784 if (*size < 128*2) return -1; //make sure buffer has enough data
615f21dd 785 size_t startIdx = 0;
0df669a2 786 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
8ad1e731 787 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
788 return -2; //preamble not found
deba67ab 789 if (*size != 128) return -3; //wrong demoded size
790 //return start position
615f21dd 791 return (int)startIdx;
792}
1e090a61 793
6c283951 794// ASK/Diphase fc/64 (inverted Biphase)
795// Note: this i s not a demod, this is only a detection
796// the parameter *dest needs to be demoded before call
deba67ab 797// 0xFFFF preamble, 64bits
6c283951 798int JablotronDemod(uint8_t *dest, size_t *size){
deba67ab 799 if (*size < 64*2) return -1; //make sure buffer has enough data
6c283951 800 size_t startIdx = 0;
deba67ab 801 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,0};
8ad1e731 802 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
803 return -2; //preamble not found
deba67ab 804 if (*size != 64) return -3; // wrong demoded size
6c283951 805
29ce214c 806 uint8_t checkchksum = 0;
6c283951 807 for (int i=16; i < 56; i += 8) {
29ce214c 808 checkchksum += bytebits_to_byte(dest+startIdx+i,8);
6c283951 809 }
29ce214c 810 checkchksum ^= 0x3A;
29ce214c 811 uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
deba67ab 812 if ( checkchksum != crc ) return -5;
6c283951 813 return (int)startIdx;
814}
815
1e090a61 816// by marshmellow
817// FSK Demod then try to locate an AWID ID
a1d17964 818int AWIDdemodFSK(uint8_t *dest, size_t *size)
1e090a61 819{
a1d17964 820 //make sure buffer has enough data
821 if (*size < 96*50) return -1;
822
823 if (justNoise(dest, *size)) return -2;
1e090a61 824
825 // FSK demodulator
a1d17964 826 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
827 if (*size < 96) return -3; //did we get a good demod?
828
829 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
830 size_t startIdx = 0;
8ad1e731 831 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
832 return -4; //preamble not found
a1d17964 833 if (*size != 96) return -5;
834 return (int)startIdx;
1e090a61 835}
836
837// by marshmellow
6426f6ba 838// FSK Demod then try to locate a Farpointe Data (pyramid) ID
a1d17964 839int PyramiddemodFSK(uint8_t *dest, size_t *size)
1e090a61 840{
f3bf15e4 841 //make sure buffer has data
842 if (*size < 128*50) return -5;
a1d17964 843
f3bf15e4 844 //test samples are not just noise
845 if (justNoise(dest, *size)) return -1;
1e090a61 846
f3bf15e4 847 // FSK demodulator
848 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
849 if (*size < 128) return -2; //did we get a good demod?
a1d17964 850 size_t startIdx = 0;
8ad1e731 851 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,1};
852 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
853 return -4; //preamble not found
a1d17964 854 if (*size != 128) return -3;
855 return (int)startIdx;
1e090a61 856}
857
0cbe0cb8 858// find nedap preamble in already demoded data
56bbb25a 859int NedapDemod(uint8_t *dest, size_t *size) {
860 //make sure buffer has data
861 if (*size < 128) return -3;
96faed21 862
56bbb25a 863 size_t startIdx = 0;
15d49e82 864 //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
865 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
8ad1e731 866 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
867 return -4; //preamble not found
56bbb25a 868 return (int) startIdx;
869}
870
3acac886 871// Find IDTEC PSK1, RF Preamble == 0x4944544B, Demodsize 64bits
872// by iceman
873int IdteckDemodPSK(uint8_t *dest, size_t *size) {
874 //make sure buffer has data
875 if (*size < 64*2) return -1;
876 size_t startIdx = 0;
877 uint8_t preamble[] = {0,1,0,0,1,0,0,1,0,1,0,0,0,1,0,0,0,1,0,1,0,1,0,0,0,1,0,0,1,0,1,1};
8ad1e731 878 if (!preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx))
879 return -2; //preamble not found
3acac886 880 if (*size != 64) return -3; // wrong demoded size
881 return (int) startIdx;
882}
883
fef74fdc 884// by marshmellow
885// to detect a wave that has heavily clipped (clean) samples
cc15a118 886uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
6de43508 887{
6426f6ba 888 bool allArePeaks = true;
6de43508 889 uint16_t cntPeaks=0;
6426f6ba 890 size_t loopEnd = 512+160;
1fbf8956 891 if (loopEnd > size) loopEnd = size;
6426f6ba 892 for (size_t i=160; i<loopEnd; i++){
6de43508 893 if (dest[i]>low && dest[i]<high)
6426f6ba 894 allArePeaks = false;
6de43508 895 else
896 cntPeaks++;
897 }
6426f6ba 898 if (!allArePeaks){
899 if (cntPeaks > 300) return true;
6de43508 900 }
6426f6ba 901 return allArePeaks;
6de43508 902}
2eec55c8 903// by marshmellow
904// to help detect clocks on heavily clipped samples
cc15a118 905// based on count of low to low
906int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
13d77ef9 907{
cc15a118 908 uint8_t fndClk[] = {8,16,32,40,50,64,128};
909 size_t startwave;
6426f6ba 910 size_t i = 100;
cc15a118 911 size_t minClk = 255;
912 // get to first full low to prime loop and skip incomplete first pulse
913 while ((dest[i] < high) && (i < size))
914 ++i;
915 while ((dest[i] > low) && (i < size))
916 ++i;
917
918 // loop through all samples
919 while (i < size) {
920 // measure from low to low
921 while ((dest[i] > low) && (i < size))
922 ++i;
923 startwave= i;
924 while ((dest[i] < high) && (i < size))
925 ++i;
926 while ((dest[i] > low) && (i < size))
927 ++i;
928 //get minimum measured distance
929 if (i-startwave < minClk && i < size)
930 minClk = i - startwave;
13d77ef9 931 }
cc15a118 932 // set clock
a126332a 933 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
cc15a118 934 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
935 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
936 return fndClk[clkCnt];
13d77ef9 937 }
cc15a118 938 return 0;
13d77ef9 939}
940
eb191de6 941// by marshmellow
942// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
943// maybe somehow adjust peak trimming value based on samples to fix?
6de43508 944// return start index of best starting position for that clock and return clock (by reference)
945int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
eb191de6 946{
6e984446 947 size_t i=1;
cc15a118 948 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
949 uint8_t clkEnd = 9;
2eec55c8 950 uint8_t loopCnt = 255; //don't need to loop through entire array...
6426f6ba 951 if (size <= loopCnt+60) return -1; //not enough samples
952 size -= 60; //sometimes there is a strange end wave - filter out this....
6e984446 953 //if we already have a valid clock
954 uint8_t clockFnd=0;
cc15a118 955 for (;i<clkEnd;++i)
956 if (clk[i] == *clock) clockFnd = i;
6e984446 957 //clock found but continue to find best startpos
e0165dcf 958
959 //get high and low peak
960 int peak, low;
2eec55c8 961 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
e0165dcf 962
963 //test for large clean peaks
cc15a118 964 if (!clockFnd){
965 if (DetectCleanAskWave(dest, size, peak, low)==1){
966 int ans = DetectStrongAskClock(dest, size, peak, low);
a126332a 967 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
cc15a118 968 for (i=clkEnd-1; i>0; i--){
969 if (clk[i] == ans) {
970 *clock = ans;
971 //clockFnd = i;
972 return 0; // for strong waves i don't use the 'best start position' yet...
973 //break; //clock found but continue to find best startpos [not yet]
974 }
e0165dcf 975 }
976 }
977 }
2eec55c8 978 uint8_t ii;
979 uint8_t clkCnt, tol = 0;
980 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
981 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
982 size_t errCnt = 0;
983 size_t arrLoc, loopEnd;
6e984446 984
cc15a118 985 if (clockFnd>0) {
986 clkCnt = clockFnd;
987 clkEnd = clockFnd+1;
81e82dfe 988 } else {
989 clkCnt=1;
cc15a118 990 }
cc15a118 991
992 //test each valid clock from smallest to greatest to see which lines up
81e82dfe 993 for(; clkCnt < clkEnd; clkCnt++) {
994 if (clk[clkCnt] <= 32) {
e0165dcf 995 tol=1;
81e82dfe 996 } else {
e0165dcf 997 tol=0;
998 }
2767fc02 999 //if no errors allowed - keep start within the first clock
81e82dfe 1000 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128)
1001 loopCnt = clk[clkCnt] * 2;
1002
1003 bestErr[clkCnt] = 1000;
1004
6e984446 1005 //try lining up the peaks by moving starting point (try first few clocks)
cc15a118 1006 for (ii=0; ii < loopCnt; ii++){
2eec55c8 1007 if (dest[ii] < peak && dest[ii] > low) continue;
1008
81e82dfe 1009 errCnt = 0;
2eec55c8 1010 // now that we have the first one lined up test rest of wave array
1011 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
1012 for (i=0; i < loopEnd; ++i){
1013 arrLoc = ii + (i * clk[clkCnt]);
1014 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
1015 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
1016 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
1017 }else{ //error no peak detected
1018 errCnt++;
e0165dcf 1019 }
1020 }
cc15a118 1021 //if we found no errors then we can stop here and a low clock (common clocks)
2eec55c8 1022 // this is correct one - return this clock
81e82dfe 1023 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d", clk[clkCnt], errCnt, ii, i);
1024 if (errCnt==0 && clkCnt<7) {
cc15a118 1025 if (!clockFnd) *clock = clk[clkCnt];
2eec55c8 1026 return ii;
1027 }
1028 //if we found errors see if it is lowest so far and save it as best run
81e82dfe 1029 if (errCnt < bestErr[clkCnt]) {
1030 bestErr[clkCnt] = errCnt;
1031 bestStart[clkCnt] = ii;
2eec55c8 1032 }
e0165dcf 1033 }
1034 }
81e82dfe 1035 uint8_t k;
1036 uint8_t best = 0;
1037 for (k=1; k < clkEnd; ++k){
1038 if (bestErr[k] < bestErr[best]){
1039 if (bestErr[k] == 0) bestErr[k]=1;
e0165dcf 1040 // current best bit to error ratio vs new bit to error ratio
81e82dfe 1041 if ( (size/clk[best])/bestErr[best] < (size/clk[k])/bestErr[k] ){
1042 best = k;
e0165dcf 1043 }
1044 }
81e82dfe 1045 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, # Errors %d, Current Best Clk %d, bestStart %d", clk[k], bestErr[k], clk[best], bestStart[best]);
e0165dcf 1046 }
cc15a118 1047 if (!clockFnd) *clock = clk[best];
e0165dcf 1048 return bestStart[best];
eb191de6 1049}
ba1a299c 1050
1051//by marshmellow
6de43508 1052//detect psk clock by reading each phase shift
1053// a phase shift is determined by measuring the sample length of each wave
1054int DetectPSKClock(uint8_t dest[], size_t size, int clock)
ba1a299c 1055{
e0165dcf 1056 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
1057 uint16_t loopCnt = 4096; //don't need to loop through entire array...
1058 if (size == 0) return 0;
6426f6ba 1059 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1060
1061 //if we already have a valid clock quit
1062 size_t i=1;
1063 for (; i < 8; ++i)
1064 if (clk[i] == clock) return clock;
1065
1066 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
1067 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
1068 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
1069 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
1070 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
2eec55c8 1071 fc = countFC(dest, size, 0);
1072 if (fc!=2 && fc!=4 && fc!=8) return -1;
a126332a 1073 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
e0165dcf 1074
1075 //find first full wave
6426f6ba 1076 for (i=160; i<loopCnt; i++){
e0165dcf 1077 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1078 if (waveStart == 0) {
1079 waveStart = i+1;
6426f6ba 1080 //prnt("DEBUG: waveStart: %d",waveStart);
e0165dcf 1081 } else {
1082 waveEnd = i+1;
6426f6ba 1083 //prnt("DEBUG: waveEnd: %d",waveEnd);
e0165dcf 1084 waveLenCnt = waveEnd-waveStart;
1085 if (waveLenCnt > fc){
1086 firstFullWave = waveStart;
1087 fullWaveLen=waveLenCnt;
1088 break;
1089 }
1090 waveStart=0;
1091 }
1092 }
1093 }
a126332a 1094 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 1095
1096 //test each valid clock from greatest to smallest to see which lines up
1097 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1098 lastClkBit = firstFullWave; //set end of wave as clock align
1099 waveStart = 0;
1100 errCnt=0;
1101 peakcnt=0;
a126332a 1102 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
e0165dcf 1103
1104 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1105 //top edge of wave = start of new wave
1106 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1107 if (waveStart == 0) {
1108 waveStart = i+1;
1109 waveLenCnt=0;
1110 } else { //waveEnd
1111 waveEnd = i+1;
1112 waveLenCnt = waveEnd-waveStart;
1113 if (waveLenCnt > fc){
1114 //if this wave is a phase shift
a126332a 1115 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);
e0165dcf 1116 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1117 peakcnt++;
1118 lastClkBit+=clk[clkCnt];
1119 } else if (i<lastClkBit+8){
1120 //noise after a phase shift - ignore
1121 } else { //phase shift before supposed to based on clock
1122 errCnt++;
1123 }
1124 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1125 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1126 }
1127 waveStart=i+1;
1128 }
1129 }
1130 }
1131 if (errCnt == 0){
1132 return clk[clkCnt];
1133 }
1134 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1135 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1136 }
1137 //all tested with errors
1138 //return the highest clk with the most peaks found
1139 uint8_t best=7;
1140 for (i=7; i>=1; i--){
1141 if (peaksdet[i] > peaksdet[best]) {
1142 best = i;
1143 }
a126332a 1144 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
e0165dcf 1145 }
1146 return clk[best];
ba1a299c 1147}
1148
6426f6ba 1149int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1150 //find shortest transition from high to low
1151 size_t i = 0;
1152 size_t transition1 = 0;
1153 int lowestTransition = 255;
1154 bool lastWasHigh = false;
1155
1156 //find first valid beginning of a high or low wave
1157 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1158 ++i;
1159 while ((dest[i] < peak && dest[i] > low) && (i < size))
1160 ++i;
1161 lastWasHigh = (dest[i] >= peak);
1162
1163 if (i==size) return 0;
1164 transition1 = i;
1165
1166 for (;i < size; i++) {
1167 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1168 lastWasHigh = (dest[i] >= peak);
1169 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1170 transition1 = i;
1171 }
1172 }
6426f6ba 1173 if (lowestTransition == 255) lowestTransition = 0;
a126332a 1174 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
6426f6ba 1175 return lowestTransition;
1176}
1177
6de43508 1178//by marshmellow
1179//detect nrz clock by reading #peaks vs no peaks(or errors)
1180int DetectNRZClock(uint8_t dest[], size_t size, int clock)
ba1a299c 1181{
2eec55c8 1182 size_t i=0;
1183 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1184 size_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1185 if (size == 0) return 0;
6426f6ba 1186 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1187 //if we already have a valid clock quit
1188 for (; i < 8; ++i)
1189 if (clk[i] == clock) return clock;
1190
1191 //get high and low peak
1192 int peak, low;
2eec55c8 1193 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
e0165dcf 1194
6426f6ba 1195 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
2eec55c8 1196 size_t ii;
e0165dcf 1197 uint8_t clkCnt;
1198 uint8_t tol = 0;
6426f6ba 1199 uint16_t smplCnt = 0;
1200 int16_t peakcnt = 0;
1201 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1202 uint16_t maxPeak = 255;
1203 bool firstpeak = false;
e0165dcf 1204 //test for large clipped waves
1205 for (i=0; i<loopCnt; i++){
1206 if (dest[i] >= peak || dest[i] <= low){
6426f6ba 1207 if (!firstpeak) continue;
1208 smplCnt++;
e0165dcf 1209 } else {
6426f6ba 1210 firstpeak=true;
1211 if (smplCnt > 6 ){
1212 if (maxPeak > smplCnt){
1213 maxPeak = smplCnt;
1214 //prnt("maxPk: %d",maxPeak);
1215 }
1216 peakcnt++;
1217 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1218 smplCnt=0;
e0165dcf 1219 }
e0165dcf 1220 }
1221 }
6426f6ba 1222 bool errBitHigh = 0;
1223 bool bitHigh = 0;
1224 uint8_t ignoreCnt = 0;
1225 uint8_t ignoreWindow = 4;
1226 bool lastPeakHigh = 0;
1227 int lastBit = 0;
e0165dcf 1228 peakcnt=0;
1229 //test each valid clock from smallest to greatest to see which lines up
1230 for(clkCnt=0; clkCnt < 8; ++clkCnt){
6426f6ba 1231 //ignore clocks smaller than smallest peak
1232 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
e0165dcf 1233 //try lining up the peaks by moving starting point (try first 256)
6426f6ba 1234 for (ii=20; ii < loopCnt; ++ii){
e0165dcf 1235 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1236 peakcnt=0;
6426f6ba 1237 bitHigh = false;
1238 ignoreCnt = 0;
1239 lastBit = ii-clk[clkCnt];
1240 //loop through to see if this start location works
1241 for (i = ii; i < size-20; ++i) {
1242 //if we are at a clock bit
1243 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1244 //test high/low
1245 if (dest[i] >= peak || dest[i] <= low) {
1246 //if same peak don't count it
1247 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
e0165dcf 1248 peakcnt++;
6426f6ba 1249 }
1250 lastPeakHigh = (dest[i] >= peak);
1251 bitHigh = true;
1252 errBitHigh = false;
1253 ignoreCnt = ignoreWindow;
1254 lastBit += clk[clkCnt];
1255 } else if (i == lastBit + clk[clkCnt] + tol) {
1256 lastBit += clk[clkCnt];
1257 }
1258 //else if not a clock bit and no peaks
1259 } else if (dest[i] < peak && dest[i] > low){
1260 if (ignoreCnt==0){
1261 bitHigh=false;
1262 if (errBitHigh==true) peakcnt--;
1263 errBitHigh=false;
1264 } else {
1265 ignoreCnt--;
1266 }
1267 // else if not a clock bit but we have a peak
1268 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1269 //error bar found no clock...
1270 errBitHigh=true;
e0165dcf 1271 }
1272 }
1273 if(peakcnt>peaksdet[clkCnt]) {
1274 peaksdet[clkCnt]=peakcnt;
1275 }
1276 }
1277 }
1278 }
1279 int iii=7;
2eec55c8 1280 uint8_t best=0;
e0165dcf 1281 for (iii=7; iii > 0; iii--){
6426f6ba 1282 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1283 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
1284 best = iii;
1285 }
1286 } else if (peaksdet[iii] > peaksdet[best]){
e0165dcf 1287 best = iii;
1288 }
a126332a 1289 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);
e0165dcf 1290 }
6426f6ba 1291
e0165dcf 1292 return clk[best];
ba1a299c 1293}
1294
04d2721b 1295// by marshmellow
1296// convert psk1 demod to psk2 demod
1297// only transition waves are 1s
4ac9f078 1298void psk1TOpsk2(uint8_t *bits, size_t size) {
1299 uint8_t lastBit = bits[0];
1300 for (size_t i = 1; i < size; i++){
1301 //ignore errors
1302 if (bits[i] == 7) continue;
1303
1304 if (lastBit != bits[i]){
1305 lastBit = bits[i];
1306 bits[i] = 1;
04d2721b 1307 } else {
4ac9f078 1308 bits[i] = 0;
04d2721b 1309 }
1310 }
04d2721b 1311}
ba1a299c 1312
3bc66a96 1313// by marshmellow
1314// convert psk2 demod to psk1 demod
1315// from only transition waves are 1s to phase shifts change bit
4ac9f078 1316void psk2TOpsk1(uint8_t *bits, size_t size) {
1317 uint8_t phase = 0;
1318 for (size_t i = 0; i < size; i++){
1319 if (bits[i] == 1){
1320 phase ^= 1;
3bc66a96 1321 }
4ac9f078 1322 bits[i] = phase;
3bc66a96 1323 }
3bc66a96 1324}
1325
04d2721b 1326// redesigned by marshmellow adjusted from existing decode functions
1327// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
ba1a299c 1328int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1329{
1330 //26 bit 40134 format (don't know other formats)
57c7b44b 1331 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};
1332 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};
1333 size_t startidx = 0;
1334 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1335 // if didn't find preamble try again inverting
1336 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1337 *invert ^= 1;
1338 }
1339 if (*size != 64 && *size != 224) return -2;
1340 if (*invert==1)
1341 for (size_t i = startidx; i < *size; i++)
1342 bitStream[i] ^= 1;
ba1a299c 1343
57c7b44b 1344 return (int) startidx;
ba1a299c 1345}
1346
05164399 1347// by marshmellow - demodulate NRZ wave - requires a read with strong signal
04d2721b 1348// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
6426f6ba 1349int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
e0165dcf 1350 if (justNoise(dest, *size)) return -1;
1351 *clk = DetectNRZClock(dest, *size, *clk);
1352 if (*clk==0) return -2;
2eec55c8 1353 size_t i, gLen = 4096;
6426f6ba 1354 if (gLen>*size) gLen = *size-20;
e0165dcf 1355 int high, low;
1356 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
6426f6ba 1357
1358 uint8_t bit=0;
1359 //convert wave samples to 1's and 0's
1360 for(i=20; i < *size-20; i++){
1361 if (dest[i] >= high) bit = 1;
1362 if (dest[i] <= low) bit = 0;
1363 dest[i] = bit;
e0165dcf 1364 }
6426f6ba 1365 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1366 size_t lastBit = 0;
1367 size_t numBits = 0;
1368 for(i=21; i < *size-20; i++) {
1369 //if transition detected or large number of same bits - store the passed bits
1370 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1371 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1372 numBits += (i - lastBit + (*clk/4)) / *clk;
1373 lastBit = i-1;
e0165dcf 1374 }
e0165dcf 1375 }
6426f6ba 1376 *size = numBits;
1377 return 0;
ba1a299c 1378}
1379
1e090a61 1380//by marshmellow
03e6bb4a 1381//detects the bit clock for FSK given the high and low Field Clocks
1382uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1e090a61 1383{
e0165dcf 1384 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1385 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1386 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1387 uint8_t rfLensFnd = 0;
2eec55c8 1388 uint8_t lastFCcnt = 0;
1389 uint16_t fcCounter = 0;
e0165dcf 1390 uint16_t rfCounter = 0;
1391 uint8_t firstBitFnd = 0;
1392 size_t i;
1393 if (size == 0) return 0;
1394
6426f6ba 1395 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
e0165dcf 1396 rfLensFnd=0;
1397 fcCounter=0;
1398 rfCounter=0;
1399 firstBitFnd=0;
a38f5a07 1400 //prnt("DEBUG: fcTol: %d",fcTol);
6426f6ba 1401 // prime i to first peak / up transition
1402 for (i = 160; i < size-20; i++)
e0165dcf 1403 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1404 break;
1405
6426f6ba 1406 for (; i < size-20; i++){
2eec55c8 1407 fcCounter++;
1408 rfCounter++;
1409
1410 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1411 continue;
1412 // else new peak
1413 // if we got less than the small fc + tolerance then set it to the small fc
8ad1e731 1414 // if it is inbetween set it to the last counter
1415 if (fcCounter < fcHigh && fcCounter > fcLow)
1416 fcCounter = lastFCcnt;
1417 else if (fcCounter < fcLow+fcTol)
2eec55c8 1418 fcCounter = fcLow;
1419 else //set it to the large fc
1420 fcCounter = fcHigh;
1421
1422 //look for bit clock (rf/xx)
1423 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1424 //not the same size as the last wave - start of new bit sequence
1425 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1426 for (int ii=0; ii<15; ii++){
6426f6ba 1427 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
2eec55c8 1428 rfCnts[ii]++;
1429 rfCounter = 0;
1430 break;
e0165dcf 1431 }
e0165dcf 1432 }
2eec55c8 1433 if (rfCounter > 0 && rfLensFnd < 15){
a38f5a07 1434 //prnt("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
2eec55c8 1435 rfCnts[rfLensFnd]++;
1436 rfLens[rfLensFnd++] = rfCounter;
1437 }
1438 } else {
1439 firstBitFnd++;
e0165dcf 1440 }
2eec55c8 1441 rfCounter=0;
1442 lastFCcnt=fcCounter;
e0165dcf 1443 }
2eec55c8 1444 fcCounter=0;
e0165dcf 1445 }
1446 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1447
1448 for (i=0; i<15; i++){
e0165dcf 1449 //get highest 2 RF values (might need to get more values to compare or compare all?)
1450 if (rfCnts[i]>rfCnts[rfHighest]){
1451 rfHighest3=rfHighest2;
1452 rfHighest2=rfHighest;
1453 rfHighest=i;
1454 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1455 rfHighest3=rfHighest2;
1456 rfHighest2=i;
1457 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1458 rfHighest3=i;
1459 }
a126332a 1460 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
e0165dcf 1461 }
1462 // set allowed clock remainder tolerance to be 1 large field clock length+1
1463 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1464 uint8_t tol1 = fcHigh+1;
1465
a126332a 1466 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
e0165dcf 1467
1468 // loop to find the highest clock that has a remainder less than the tolerance
1469 // compare samples counted divided by
6426f6ba 1470 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
e0165dcf 1471 int ii=7;
6426f6ba 1472 for (; ii>=2; ii--){
e0165dcf 1473 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1474 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1475 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
a126332a 1476 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
e0165dcf 1477 break;
1478 }
1479 }
1480 }
1481 }
1482
8ad1e731 1483 if (ii<2) return 0; // oops we went too far
e0165dcf 1484
1485 return clk[ii];
03e6bb4a 1486}
1e090a61 1487
03e6bb4a 1488//by marshmellow
1489//countFC is to detect the field clock lengths.
1490//counts and returns the 2 most common wave lengths
6de43508 1491//mainly used for FSK field clock detection
2eec55c8 1492uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
03e6bb4a 1493{
6426f6ba 1494 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1495 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
e0165dcf 1496 uint8_t fcLensFnd = 0;
1a4b9073 1497 uint8_t lastFCcnt = 0;
2eec55c8 1498 uint8_t fcCounter = 0;
e0165dcf 1499 size_t i;
1a4b9073 1500 if (size < 180) return 0;
e0165dcf 1501
1502 // prime i to first up transition
6426f6ba 1503 for (i = 160; i < size-20; i++)
e0165dcf 1504 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1505 break;
1506
6426f6ba 1507 for (; i < size-20; i++){
e0165dcf 1508 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1509 // new up transition
1510 fcCounter++;
2eec55c8 1511 if (fskAdj){
1512 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1513 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1514 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1515 if ((fcCounter==9) || fcCounter==4) fcCounter++;
e0165dcf 1516 // save last field clock count (fc/xx)
2eec55c8 1517 lastFCcnt = fcCounter;
1518 }
e0165dcf 1519 // find which fcLens to save it to:
6426f6ba 1520 for (int ii=0; ii<15; ii++){
e0165dcf 1521 if (fcLens[ii]==fcCounter){
1522 fcCnts[ii]++;
1523 fcCounter=0;
1524 break;
1525 }
1526 }
6426f6ba 1527 if (fcCounter>0 && fcLensFnd<15){
e0165dcf 1528 //add new fc length
1529 fcCnts[fcLensFnd]++;
1530 fcLens[fcLensFnd++]=fcCounter;
1531 }
1532 fcCounter=0;
1533 } else {
1534 // count sample
1535 fcCounter++;
1536 }
1537 }
1538
6426f6ba 1539 uint8_t best1=14, best2=14, best3=14;
e0165dcf 1540 uint16_t maxCnt1=0;
1541 // go through fclens and find which ones are bigest 2
6426f6ba 1542 for (i=0; i<15; i++){
e0165dcf 1543 // get the 3 best FC values
1544 if (fcCnts[i]>maxCnt1) {
1545 best3=best2;
1546 best2=best1;
1547 maxCnt1=fcCnts[i];
1548 best1=i;
1549 } else if(fcCnts[i]>fcCnts[best2]){
1550 best3=best2;
1551 best2=i;
1552 } else if(fcCnts[i]>fcCnts[best3]){
1553 best3=i;
1554 }
a126332a 1555 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]);
e0165dcf 1556 }
6426f6ba 1557 if (fcLens[best1]==0) return 0;
e0165dcf 1558 uint8_t fcH=0, fcL=0;
1559 if (fcLens[best1]>fcLens[best2]){
1560 fcH=fcLens[best1];
1561 fcL=fcLens[best2];
1562 } else{
1563 fcH=fcLens[best2];
1564 fcL=fcLens[best1];
1565 }
a126332a 1566 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1567 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]);
1568 return 0; //lots of waves not psk or fsk
1569 }
e0165dcf 1570 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1571
1572 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
2eec55c8 1573 if (fskAdj) return fcs;
1574 return fcLens[best1];
6de43508 1575}
1576
1577//by marshmellow - demodulate PSK1 wave
1578//uses wave lengths (# Samples)
1579int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1580{
e0165dcf 1581 if (size == 0) return -1;
2eec55c8 1582 uint16_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1583 if (*size<loopCnt) loopCnt = *size;
1584
6426f6ba 1585 size_t numBits=0;
e0165dcf 1586 uint8_t curPhase = *invert;
4ac9f078 1587 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
8ad1e731 1588 uint16_t fc=0, fullWaveLen=0, tol=1;
1589 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1590 fc = countFC(dest, *size, 1);
1591 uint8_t fc2 = fc >> 8;
1592 if (fc2 == 10) return -1; //fsk found - quit
1593 fc = fc & 0xFF;
e0165dcf 1594 if (fc!=2 && fc!=4 && fc!=8) return -1;
a38f5a07 1595 //prnt("DEBUG: FC: %d",fc);
e0165dcf 1596 *clock = DetectPSKClock(dest, *size, *clock);
2eec55c8 1597 if (*clock == 0) return -1;
4ac9f078 1598
8ad1e731 1599 //find start of modulating data in trace
1600 uint8_t threshold_value = 123; //-5
1601 i = findModStart(dest, *size, threshold_value, fc);
4ac9f078 1602
e0165dcf 1603 //find first phase shift
8ad1e731 1604 int avgWaveVal=0, lastAvgWaveVal=0;
1605 waveStart = i;
4ac9f078 1606 for (; i<loopCnt; i++){
8ad1e731 1607 // find peak
e0165dcf 1608 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1609 waveEnd = i+1;
4ac9f078 1610 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
e0165dcf 1611 waveLenCnt = waveEnd-waveStart;
4ac9f078 1612 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
e0165dcf 1613 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1614 firstFullWave = waveStart;
1615 fullWaveLen=waveLenCnt;
8ad1e731 1616 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1617 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
e0165dcf 1618 break;
1619 }
1620 waveStart = i+1;
1621 avgWaveVal = 0;
1622 }
2eec55c8 1623 avgWaveVal += dest[i+2];
e0165dcf 1624 }
6426f6ba 1625 if (firstFullWave == 0) {
1626 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1627 // so skip a little to ensure we are past any Start Signal
1628 firstFullWave = 160;
1629 memset(dest, curPhase, firstFullWave / *clock);
1630 } else {
1631 memset(dest, curPhase^1, firstFullWave / *clock);
1632 }
1633 //advance bits
1634 numBits += (firstFullWave / *clock);
1635 //set start of wave as clock align
1636 lastClkBit = firstFullWave;
7fa7e812 1637 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
8ad1e731 1638 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
e0165dcf 1639 waveStart = 0;
e0165dcf 1640 dest[numBits++] = curPhase; //set first read bit
2eec55c8 1641 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
e0165dcf 1642 //top edge of wave = start of new wave
1643 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1644 if (waveStart == 0) {
1645 waveStart = i+1;
2eec55c8 1646 waveLenCnt = 0;
e0165dcf 1647 avgWaveVal = dest[i+1];
1648 } else { //waveEnd
1649 waveEnd = i+1;
1650 waveLenCnt = waveEnd-waveStart;
1651 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1652 if (waveLenCnt > fc){
a38f5a07 1653 //prnt("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
2eec55c8 1654 //this wave is a phase shift
a38f5a07 1655 //prnt("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
e0165dcf 1656 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
2eec55c8 1657 curPhase ^= 1;
e0165dcf 1658 dest[numBits++] = curPhase;
1659 lastClkBit += *clock;
2eec55c8 1660 } else if (i < lastClkBit+10+fc){
e0165dcf 1661 //noise after a phase shift - ignore
1662 } else { //phase shift before supposed to based on clock
1663 errCnt++;
2767fc02 1664 dest[numBits++] = 7;
e0165dcf 1665 }
1666 } else if (i+1 > lastClkBit + *clock + tol + fc){
1667 lastClkBit += *clock; //no phase shift but clock bit
1668 dest[numBits++] = curPhase;
8ad1e731 1669 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1670 errCnt2++;
1671 if(errCnt2 > 101) return errCnt2;
e0165dcf 1672 }
2eec55c8 1673 avgWaveVal = 0;
1674 waveStart = i+1;
e0165dcf 1675 }
1676 }
2eec55c8 1677 avgWaveVal += dest[i+1];
e0165dcf 1678 }
1679 *size = numBits;
1680 return errCnt;
6de43508 1681}
05164399 1682
1683//by marshmellow
1684//attempt to identify a Sequence Terminator in ASK modulated raw wave
1685bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1686 size_t bufsize = *size;
1687 //need to loop through all samples and identify our clock, look for the ST pattern
1688 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1689 int clk = 0;
1690 int tol = 0;
1691 int i, j, skip, start, end, low, high, minClk, waveStart;
1692 bool complete = false;
a38f5a07 1693 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1694 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
05164399 1695 size_t testsize = (bufsize < 512) ? bufsize : 512;
1696 int phaseoff = 0;
1697 high = low = 128;
1698 memset(tmpbuff, 0, sizeof(tmpbuff));
a38f5a07 1699 memset(waveLen, 0, sizeof(waveLen));
05164399 1700
a38f5a07 1701
05164399 1702 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1703 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1704 return false; //just noise
1705 }
1706 i = 0;
1707 j = 0;
1708 minClk = 255;
1709 // get to first full low to prime loop and skip incomplete first pulse
1710 while ((buffer[i] < high) && (i < bufsize))
1711 ++i;
1712 while ((buffer[i] > low) && (i < bufsize))
1713 ++i;
1714 skip = i;
1715
1716 // populate tmpbuff buffer with pulse lengths
1717 while (i < bufsize) {
1718 // measure from low to low
1719 while ((buffer[i] > low) && (i < bufsize))
1720 ++i;
1721 start= i;
1722 while ((buffer[i] < high) && (i < bufsize))
1723 ++i;
1724 //first high point for this wave
1725 waveStart = i;
1726 while ((buffer[i] > low) && (i < bufsize))
1727 ++i;
a38f5a07 1728 if (j >= (bufsize/32)) {
05164399 1729 break;
1730 }
1731 waveLen[j] = i - waveStart; //first high to first low
1732 tmpbuff[j++] = i - start;
1733 if (i-start < minClk && i < bufsize) {
1734 minClk = i - start;
1735 }
1736 }
1737 // set clock - might be able to get this externally and remove this work...
1738 if (!clk) {
1739 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1740 tol = fndClk[clkCnt]/8;
1741 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1742 clk=fndClk[clkCnt];
1743 break;
1744 }
1745 }
1746 // clock not found - ERROR
1747 if (!clk) {
1748 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1749 return false;
1750 }
1751 } else tol = clk/8;
1752
1753 *foundclock = clk;
1754
1755 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1756 start = -1;
1757 for (i = 0; i < j - 4; ++i) {
1758 skip += 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 start = i + 3;
1764 break;
1765 }
1766 }
1767 }
1768 }
1769 }
1770 // first ST not found - ERROR
1771 if (start < 0) {
1772 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1773 return false;
a38f5a07 1774 } else {
1775 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
05164399 1776 }
1777 if (waveLen[i+2] > clk*1+tol)
1778 phaseoff = 0;
1779 else
1780 phaseoff = clk/2;
1781
1782 // skip over the remainder of ST
1783 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1784
1785 // now do it again to find the end
1786 end = skip;
1787 for (i += 3; i < j - 4; ++i) {
1788 end += tmpbuff[i];
a38f5a07 1789 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
05164399 1790 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
1791 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
1792 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1793 complete = true;
1794 break;
1795 }
1796 }
1797 }
1798 }
1799 }
1800 end -= phaseoff;
1801 //didn't find second ST - ERROR
1802 if (!complete) {
1803 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1804 return false;
1805 }
1806 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);
1807 //now begin to trim out ST so we can use normal demod cmds
1808 start = skip;
1809 size_t datalen = end - start;
1810 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
a38f5a07 1811 if ( clk - (datalen % clk) <= clk/8) {
1812 // padd the amount off - could be problematic... but shouldn't happen often
1813 datalen += clk - (datalen % clk);
1814 } else if ( (datalen % clk) <= clk/8 ) {
1815 // padd the amount off - could be problematic... but shouldn't happen often
1816 datalen -= datalen % clk;
1817 } else {
05164399 1818 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1819 return false;
05164399 1820 }
1821 // if datalen is less than one t55xx block - ERROR
1822 if (datalen/clk < 8*4) {
1823 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1824 return false;
1825 }
1826 size_t dataloc = start;
a38f5a07 1827 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1828 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1829 for ( i=0; i <= (clk/8); ++i ) {
1830 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1831 dataloc -= i;
1832 break;
1833 }
1834 }
1835 }
1836
05164399 1837 size_t newloc = 0;
1838 i=0;
a38f5a07 1839 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1840
05164399 1841 // warning - overwriting buffer given with raw wave data with ST removed...
1842 while ( dataloc < bufsize-(clk/2) ) {
7fa7e812 1843 //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)
05164399 1844 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1845 for(i=0; i < clk/2-tol; ++i) {
1846 buffer[dataloc+i] = high+5;
1847 }
c24364a8 1848 } //test for single sample outlier (high between two lows) in the case of very strong waves
1849 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1850 buffer[dataloc] = buffer[dataloc+2];
1851 buffer[dataloc+1] = buffer[dataloc+2];
05164399 1852 }
1853 for (i=0; i<datalen; ++i) {
1854 if (i+newloc < bufsize) {
1855 if (i+newloc < dataloc)
1856 buffer[i+newloc] = buffer[dataloc];
1857
1858 dataloc++;
1859 }
1860 }
1861 newloc += i;
7fa7e812 1862 //skip next ST - we just assume it will be there from now on...
a38f5a07 1863 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
05164399 1864 dataloc += clk*4;
1865 }
1866 *size = newloc;
1867 return true;
1868}
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