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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//-----------------------------------------------------------------------------
10
eb191de6 11#include <stdlib.h>
eb191de6 12#include "lfdemod.h"
05164399 13#include <string.h>
6426f6ba 14
a126332a 15//un_comment to allow debug print calls when used not on device
6426f6ba 16void dummy(char *fmt, ...){}
17
18#ifndef ON_DEVICE
19#include "ui.h"
a126332a 20#include "cmdparser.h"
21#include "cmddata.h"
6426f6ba 22#define prnt PrintAndLog
23#else
a126332a 24 uint8_t g_debugMode=0;
6426f6ba 25#define prnt dummy
26#endif
6426f6ba 27
a1d17964 28uint8_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
1e090a61 39//by marshmellow
872e3d4d 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
1e090a61 41int 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
2eec55c8 46 for (size_t i=0; i < size; i++){
1e090a61 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
75cbbe9a 51 *high = ((*high-128)*fuzzHi + 12800)/100;
52 *low = ((*low-128)*fuzzLo + 12800)/100;
1e090a61 53 return 1;
54}
55
a1d17964 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
59uint8_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 }
f3bf15e4 65 //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
a1d17964 66 return (ans == pType);
67}
68
a126332a 69//by marshmellow
70// takes a array of binary values, start position, length of bits per parity (includes parity bit),
c728b2b4 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)
a126332a 72size_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 j--; // overwrite parity with next data
82 // if parity fails then return 0
c728b2b4 83 switch (pType) {
84 case 3: if (BitStream[j]==1) return 0; break; //should be 0 spacer bit
85 case 2: if (BitStream[j]==0) return 0; break; //should be 1 spacer bit
86 default: //test parity
87 if (parityTest(parityWd, pLen, pType) == 0) return 0; break;
a126332a 88 }
89 bitCnt+=(pLen-1);
90 parityWd = 0;
91 }
92 // if we got here then all the parities passed
93 //return ID start index and size
94 return bitCnt;
95}
96
97// by marshmellow
98// takes a array of binary values, length of bits per parity (includes parity bit),
0d2c5909 99// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
c728b2b4 100// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
a126332a 101size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
102{
103 uint32_t parityWd = 0;
104 size_t j = 0, bitCnt = 0;
105 for (int word = 0; word < sourceLen; word+=pLen-1) {
106 for (int bit=0; bit < pLen-1; bit++){
107 parityWd = (parityWd << 1) | BitSource[word+bit];
108 dest[j++] = (BitSource[word+bit]);
109 }
0d2c5909 110
a126332a 111 // if parity fails then return 0
0d2c5909 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;
a126332a 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
127uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
128{
129 uint32_t num = 0;
0d2c5909 130 for(int i = 0 ; i < numbits ; i++) {
a126332a 131 num = (num << 1) | (*src);
132 src++;
133 }
134 return num;
135}
136
137//least significant bit first
138uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
139{
140 uint32_t num = 0;
6b6815bc 141 for(int i = 0 ; i < numbits ; i++) {
a126332a 142 num = (num << 1) | *(src + (numbits-(i+1)));
143 }
144 return num;
145}
146
a1d17964 147//by marshmellow
2147c307 148//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
a1d17964 149uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
150{
e0165dcf 151 uint8_t foundCnt=0;
152 for (int idx=0; idx < *size - pLen; idx++){
153 if (memcmp(BitStream+idx, preamble, pLen) == 0){
154 //first index found
155 foundCnt++;
156 if (foundCnt == 1){
157 *startIdx = idx;
158 }
159 if (foundCnt == 2){
160 *size = idx - *startIdx;
161 return 1;
162 }
163 }
164 }
165 return 0;
a1d17964 166}
167
2147c307 168//by marshmellow
169//takes 1s and 0s and searches for EM410x format - output EM ID
170uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
171{
e0165dcf 172 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
173 // otherwise could be a void with no arguments
174 //set defaults
175 uint32_t i = 0;
2767fc02 176 if (BitStream[1]>1) return 0; //allow only 1s and 0s
177
e0165dcf 178 // 111111111 bit pattern represent start of frame
179 // include 0 in front to help get start pos
180 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
181 uint32_t idx = 0;
182 uint32_t parityBits = 0;
183 uint8_t errChk = 0;
184 uint8_t FmtLen = 10;
185 *startIdx = 0;
186 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
187 if (errChk == 0 || *size < 64) return 0;
188 if (*size > 64) FmtLen = 22;
189 *startIdx += 1; //get rid of 0 from preamble
190 idx = *startIdx + 9;
191 for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
192 parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
2eec55c8 193 //check even parity - quit if failed
194 if (parityTest(parityBits, 5, 0) == 0) return 0;
e0165dcf 195 //set uint64 with ID from BitStream
196 for (uint8_t ii=0; ii<4; ii++){
197 *hi = (*hi << 1) | (*lo >> 63);
198 *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
199 }
200 }
201 if (errChk != 0) return 1;
202 //skip last 5 bit parity test for simplicity.
203 // *size = 64 | 128;
204 return 0;
2147c307 205}
206
fef74fdc 207//by marshmellow
208//demodulates strong heavily clipped samples
23f0a7d8 209int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
210{
211 size_t bitCnt=0, smplCnt=0, errCnt=0;
212 uint8_t waveHigh = 0;
23f0a7d8 213 for (size_t i=0; i < *size; i++){
214 if (BinStream[i] >= high && waveHigh){
215 smplCnt++;
216 } else if (BinStream[i] <= low && !waveHigh){
217 smplCnt++;
218 } else { //transition
219 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
220 if (smplCnt > clk-(clk/4)-1) { //full clock
221 if (smplCnt > clk + (clk/4)+1) { //too many samples
222 errCnt++;
05164399 223 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
2767fc02 224 BinStream[bitCnt++]=7;
23f0a7d8 225 } else if (waveHigh) {
226 BinStream[bitCnt++] = invert;
227 BinStream[bitCnt++] = invert;
228 } else if (!waveHigh) {
229 BinStream[bitCnt++] = invert ^ 1;
230 BinStream[bitCnt++] = invert ^ 1;
231 }
232 waveHigh ^= 1;
233 smplCnt = 0;
234 } else if (smplCnt > (clk/2) - (clk/4)-1) {
235 if (waveHigh) {
236 BinStream[bitCnt++] = invert;
237 } else if (!waveHigh) {
238 BinStream[bitCnt++] = invert ^ 1;
239 }
240 waveHigh ^= 1;
241 smplCnt = 0;
242 } else if (!bitCnt) {
243 //first bit
244 waveHigh = (BinStream[i] >= high);
245 smplCnt = 1;
246 } else {
247 smplCnt++;
248 //transition bit oops
249 }
250 } else { //haven't hit new high or new low yet
251 smplCnt++;
252 }
253 }
254 }
255 *size = bitCnt;
256 return errCnt;
257}
258
eb191de6 259//by marshmellow
fef74fdc 260void askAmp(uint8_t *BitStream, size_t size)
261{
9686a8d4 262 uint8_t last = 128;
263 for(size_t i = 1; i < size; ++i){
264 if (BitStream[i]-BitStream[i-1] >= 30) //large jump up
265 last = 255;
266 else if(BitStream[i-1] - BitStream[i] >= 20) //large jump down
267 last = 0;
268
269 BitStream[i] = last;
fef74fdc 270 }
fef74fdc 271}
272
273//by marshmellow
274//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
275int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
eb191de6 276{
fef74fdc 277 if (*size==0) return -1;
6e984446 278 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
2eec55c8 279 if (*clk==0 || start < 0) return -3;
fef74fdc 280 if (*invert != 1) *invert = 0;
281 if (amp==1) askAmp(BinStream, *size);
05164399 282 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d", *clk, start);
fef74fdc 283
2eec55c8 284 uint8_t initLoopMax = 255;
285 if (initLoopMax > *size) initLoopMax = *size;
ba1a299c 286 // Detect high and lows
fef74fdc 287 //25% clip in case highs and lows aren't clipped [marshmellow]
2eec55c8 288 int high, low;
fef74fdc 289 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
290 return -2; //just noise
ba1a299c 291
fef74fdc 292 size_t errCnt = 0;
23f0a7d8 293 // if clean clipped waves detected run alternate demod
294 if (DetectCleanAskWave(BinStream, *size, high, low)) {
05164399 295 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
fef74fdc 296 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
297 if (askType) //askman
298 return manrawdecode(BinStream, size, 0);
299 else //askraw
300 return errCnt;
23f0a7d8 301 }
05164399 302 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
23f0a7d8 303
fef74fdc 304 int lastBit; //set first clock check - can go negative
305 size_t i, bitnum = 0; //output counter
306 uint8_t midBit = 0;
2eec55c8 307 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 308 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 309 size_t MaxBits = 3072; //max bits to collect
6e984446 310 lastBit = start - *clk;
fef74fdc 311
6e984446 312 for (i = start; i < *size; ++i) {
fef74fdc 313 if (i-lastBit >= *clk-tol){
314 if (BinStream[i] >= high) {
315 BinStream[bitnum++] = *invert;
316 } else if (BinStream[i] <= low) {
317 BinStream[bitnum++] = *invert ^ 1;
318 } else if (i-lastBit >= *clk+tol) {
319 if (bitnum > 0) {
05164399 320 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
fef74fdc 321 BinStream[bitnum++]=7;
322 errCnt++;
323 }
324 } else { //in tolerance - looking for peak
325 continue;
326 }
327 midBit = 0;
2eec55c8 328 lastBit += *clk;
fef74fdc 329 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
330 if (BinStream[i] >= high) {
331 BinStream[bitnum++] = *invert;
332 } else if (BinStream[i] <= low) {
333 BinStream[bitnum++] = *invert ^ 1;
334 } else if (i-lastBit >= *clk/2+tol) {
335 BinStream[bitnum] = BinStream[bitnum-1];
336 bitnum++;
337 } else { //in tolerance - looking for peak
338 continue;
339 }
340 midBit = 1;
2eec55c8 341 }
342 if (bitnum >= MaxBits) break;
ba1a299c 343 }
2eec55c8 344 *size = bitnum;
6e984446 345 return errCnt;
eb191de6 346}
347
348//by marshmellow
349//take 10 and 01 and manchester decode
350//run through 2 times and take least errCnt
fef74fdc 351int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
eb191de6 352{
13d77ef9 353 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
354 size_t i, ii;
355 uint16_t bestErr = 1000, bestRun = 0;
fef74fdc 356 if (*size < 16) return -1;
2767fc02 357 //find correct start position [alignment]
13d77ef9 358 for (ii=0;ii<2;++ii){
fef74fdc 359 for (i=ii; i<*size-3; i+=2)
2eec55c8 360 if (BitStream[i]==BitStream[i+1])
ba1a299c 361 errCnt++;
2eec55c8 362
ba1a299c 363 if (bestErr>errCnt){
364 bestErr=errCnt;
365 bestRun=ii;
366 }
367 errCnt=0;
368 }
2767fc02 369 //decode
fef74fdc 370 for (i=bestRun; i < *size-3; i+=2){
23f0a7d8 371 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
fef74fdc 372 BitStream[bitnum++]=invert;
23f0a7d8 373 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
fef74fdc 374 BitStream[bitnum++]=invert^1;
23f0a7d8 375 } else {
2767fc02 376 BitStream[bitnum++]=7;
ba1a299c 377 }
23f0a7d8 378 if(bitnum>MaxBits) break;
ba1a299c 379 }
23f0a7d8 380 *size=bitnum;
2eec55c8 381 return bestErr;
f822a063 382}
383
1d0ccbe0 384uint32_t manchesterEncode2Bytes(uint16_t datain) {
385 uint32_t output = 0;
386 uint8_t curBit = 0;
387 for (uint8_t i=0; i<16; i++) {
388 curBit = (datain >> (15-i) & 1);
389 output |= (1<<(((15-i)*2)+curBit));
390 }
391 return output;
392}
393
fef74fdc 394//by marshmellow
395//encode binary data into binary manchester
396int ManchesterEncode(uint8_t *BitStream, size_t size)
397{
398 size_t modIdx=20000, i=0;
399 if (size>modIdx) return -1;
400 for (size_t idx=0; idx < size; idx++){
401 BitStream[idx+modIdx++] = BitStream[idx];
402 BitStream[idx+modIdx++] = BitStream[idx]^1;
403 }
404 for (; i<(size*2); i++){
405 BitStream[i] = BitStream[i+20000];
406 }
407 return i;
408}
409
f822a063 410//by marshmellow
2147c307 411//take 01 or 10 = 1 and 11 or 00 = 0
412//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
13d77ef9 413//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1e090a61 414int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
f822a063 415{
2eec55c8 416 uint16_t bitnum = 0;
417 uint16_t errCnt = 0;
418 size_t i = offset;
2147c307 419 uint16_t MaxBits=512;
420 //if not enough samples - error
421 if (*size < 51) return -1;
422 //check for phase change faults - skip one sample if faulty
423 uint8_t offsetA = 1, offsetB = 1;
424 for (; i<48; i+=2){
425 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
426 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
427 }
428 if (!offsetA && offsetB) offset++;
429 for (i=offset; i<*size-3; i+=2){
430 //check for phase error
13d77ef9 431 if (BitStream[i+1]==BitStream[i+2]) {
2767fc02 432 BitStream[bitnum++]=7;
2147c307 433 errCnt++;
434 }
ba1a299c 435 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1e090a61 436 BitStream[bitnum++]=1^invert;
ba1a299c 437 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1e090a61 438 BitStream[bitnum++]=invert;
ba1a299c 439 } else {
2767fc02 440 BitStream[bitnum++]=7;
ba1a299c 441 errCnt++;
442 }
6de43508 443 if(bitnum>MaxBits) break;
ba1a299c 444 }
445 *size=bitnum;
446 return errCnt;
eb191de6 447}
448
fef74fdc 449// by marshmellow
11081e04 450// demod gProxIIDemod
451// error returns as -x
452// success returns start position in BitStream
453// BitStream must contain previously askrawdemod and biphasedemoded data
454int gProxII_Demod(uint8_t BitStream[], size_t *size)
455{
456 size_t startIdx=0;
457 uint8_t preamble[] = {1,1,1,1,1,0};
458
459 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
460 if (errChk == 0) return -3; //preamble not found
461 if (*size != 96) return -2; //should have found 96 bits
462 //check first 6 spacer bits to verify format
463 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
464 //confirmed proper separator bits found
465 //return start position
466 return (int) startIdx;
467 }
7fa7e812 468 return -5; //spacer bits not found - not a valid gproxII
11081e04 469}
470
7fa7e812 471//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
f822a063 472size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
eb191de6 473{
2eec55c8 474 size_t last_transition = 0;
475 size_t idx = 1;
ac3ba7ee 476 //uint32_t maxVal=0;
ba1a299c 477 if (fchigh==0) fchigh=10;
478 if (fclow==0) fclow=8;
84871873 479 //set the threshold close to 0 (graph) or 128 std to avoid static
480 uint8_t threshold_value = 123;
ac2df346 481 size_t preLastSample = 0;
482 size_t LastSample = 0;
483 size_t currSample = 0;
ba1a299c 484 // sync to first lo-hi transition, and threshold
485
486 // Need to threshold first sample
6426f6ba 487 // skip 160 samples to allow antenna/samples to settle
488 if(dest[160] < threshold_value) dest[0] = 0;
ba1a299c 489 else dest[0] = 1;
490
491 size_t numBits = 0;
492 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
cd0bed3c 493 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
ba1a299c 494 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
7fa7e812 495 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
6426f6ba 496 for(idx = 161; idx < size-20; idx++) {
ba1a299c 497 // threshold current value
498
499 if (dest[idx] < threshold_value) dest[idx] = 0;
500 else dest[idx] = 1;
501
502 // Check for 0->1 transition
7fa7e812 503 if (dest[idx-1] < dest[idx]) {
ac2df346 504 preLastSample = LastSample;
505 LastSample = currSample;
506 currSample = idx-last_transition;
6426f6ba 507 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
ba1a299c 508 //do nothing with extra garbage
7fa7e812 509 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
510 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
6426f6ba 511 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){
7fa7e812 512 dest[numBits-1]=1;
ac2df346 513 }
2eec55c8 514 dest[numBits++]=1;
ac2df346 515
7fa7e812 516 } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = unusable garbage
13d77ef9 517 //do nothing with beginning garbage
7fa7e812 518 } 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 519 dest[numBits++]=1;
7fa7e812 520 } else { //9+ = 10 sample waves (or 6+ = 7)
2eec55c8 521 dest[numBits++]=0;
ba1a299c 522 }
523 last_transition = idx;
ba1a299c 524 }
525 }
526 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
eb191de6 527}
528
ba1a299c 529//translate 11111100000 to 10
7fa7e812 530//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
2eec55c8 531size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
e0165dcf 532 uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 533{
ba1a299c 534 uint8_t lastval=dest[0];
2eec55c8 535 size_t idx=0;
ba1a299c 536 size_t numBits=0;
537 uint32_t n=1;
ba1a299c 538 for( idx=1; idx < size; idx++) {
13d77ef9 539 n++;
2eec55c8 540 if (dest[idx]==lastval) continue;
541
7fa7e812 542 //find out how many bits (n) we collected
ba1a299c 543 //if lastval was 1, we have a 1->0 crossing
13d77ef9 544 if (dest[idx-1]==1) {
75cbbe9a 545 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 546 } else {// 0->1 crossing
75cbbe9a 547 n = (n * fchigh + rfLen/2) / rfLen;
ba1a299c 548 }
549 if (n == 0) n = 1;
550
7fa7e812 551 //add to our destination the bits we collected
2eec55c8 552 memset(dest+numBits, dest[idx-1]^invert , n);
553 numBits += n;
ba1a299c 554 n=0;
555 lastval=dest[idx];
556 }//end for
13d77ef9 557 // if valid extra bits at the end were all the same frequency - add them in
75cbbe9a 558 if (n > rfLen/fchigh) {
13d77ef9 559 if (dest[idx-2]==1) {
75cbbe9a 560 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 561 } else {
75cbbe9a 562 n = (n * fchigh + rfLen/2) / rfLen;
13d77ef9 563 }
2eec55c8 564 memset(dest+numBits, dest[idx-1]^invert , n);
13d77ef9 565 numBits += n;
566 }
ba1a299c 567 return numBits;
eb191de6 568}
6426f6ba 569
eb191de6 570//by marshmellow (from holiman's base)
571// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
f822a063 572int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 573{
ba1a299c 574 // FSK demodulator
575 size = fsk_wave_demod(dest, size, fchigh, fclow);
2eec55c8 576 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
ba1a299c 577 return size;
eb191de6 578}
a1d17964 579
eb191de6 580// loop to get raw HID waveform then FSK demodulate the TAG ID from it
ec75f5c1 581int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
eb191de6 582{
e0165dcf 583 if (justNoise(dest, *size)) return -1;
584
585 size_t numStart=0, size2=*size, startIdx=0;
586 // FSK demodulator
587 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
2eec55c8 588 if (*size < 96*2) return -2;
e0165dcf 589 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
590 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
591 // find bitstring in array
592 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
593 if (errChk == 0) return -3; //preamble not found
594
595 numStart = startIdx + sizeof(preamble);
596 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
597 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
598 if (dest[idx] == dest[idx+1]){
599 return -4; //not manchester data
600 }
601 *hi2 = (*hi2<<1)|(*hi>>31);
602 *hi = (*hi<<1)|(*lo>>31);
603 //Then, shift in a 0 or one into low
604 if (dest[idx] && !dest[idx+1]) // 1 0
605 *lo=(*lo<<1)|1;
606 else // 0 1
607 *lo=(*lo<<1)|0;
608 }
609 return (int)startIdx;
eb191de6 610}
611
ec75f5c1 612// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
a1d17964 613int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
ec75f5c1 614{
a1d17964 615 if (justNoise(dest, *size)) return -1;
616
617 size_t numStart=0, size2=*size, startIdx=0;
ec75f5c1 618 // FSK demodulator
a1d17964 619 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
620 if (*size < 96) return -2;
ec75f5c1 621
a1d17964 622 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
623 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
624
625 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
626 if (errChk == 0) return -3; //preamble not found
627
628 numStart = startIdx + sizeof(preamble);
629 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
630 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
631 if (dest[idx] == dest[idx+1])
632 return -4; //not manchester data
633 *hi2 = (*hi2<<1)|(*hi>>31);
634 *hi = (*hi<<1)|(*lo>>31);
635 //Then, shift in a 0 or one into low
636 if (dest[idx] && !dest[idx+1]) // 1 0
637 *lo=(*lo<<1)|1;
638 else // 0 1
639 *lo=(*lo<<1)|0;
ec75f5c1 640 }
a1d17964 641 return (int)startIdx;
ec75f5c1 642}
643
eb191de6 644int IOdemodFSK(uint8_t *dest, size_t size)
645{
a1d17964 646 if (justNoise(dest, size)) return -1;
ba1a299c 647 //make sure buffer has data
a1d17964 648 if (size < 66*64) return -2;
ba1a299c 649 // FSK demodulator
a1d17964 650 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
651 if (size < 65) return -3; //did we get a good demod?
ba1a299c 652 //Index map
653 //0 10 20 30 40 50 60
654 //| | | | | | |
655 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
656 //-----------------------------------------------------------------------------
657 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
658 //
659 //XSF(version)facility:codeone+codetwo
660 //Handle the data
a1d17964 661 size_t startIdx = 0;
662 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
663 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
664 if (errChk == 0) return -4; //preamble not found
eb191de6 665
a1d17964 666 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
667 //confirmed proper separator bits found
668 //return start position
669 return (int) startIdx;
1e090a61 670 }
a1d17964 671 return -5;
1e090a61 672}
673
70459879 674// by marshmellow
675// find viking preamble 0xF200 in already demoded data
676int VikingDemod_AM(uint8_t *dest, size_t *size) {
70459879 677 //make sure buffer has data
678 if (*size < 64*2) return -2;
679
680 size_t startIdx = 0;
681 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};
682 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
683 if (errChk == 0) return -4; //preamble not found
c0afa86f 684 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^
685 bytebits_to_byte(dest+startIdx+8,8) ^
686 bytebits_to_byte(dest+startIdx+16,8) ^
687 bytebits_to_byte(dest+startIdx+24,8) ^
688 bytebits_to_byte(dest+startIdx+32,8) ^
689 bytebits_to_byte(dest+startIdx+40,8) ^
690 bytebits_to_byte(dest+startIdx+48,8) ^
691 bytebits_to_byte(dest+startIdx+56,8);
692 if ( checkCalc != 0xA8 ) return -5;
57c7b44b 693 if (*size != 64) return -6;
70459879 694 //return start position
695 return (int) startIdx;
696}
697
4469412e 698// find presco preamble 0x10D in already demoded data
699int PrescoDemod(uint8_t *dest, size_t *size) {
700 //make sure buffer has data
701 if (*size < 64*2) return -2;
702
703 size_t startIdx = 0;
704 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
705 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
706 if (errChk == 0) return -4; //preamble not found
707 //return start position
708 return (int) startIdx;
709}
710
615f21dd 711// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
0df669a2 712// BitStream must contain previously askrawdemod and biphasedemoded data
ad6219fc 713int FDXBdemodBI(uint8_t *dest, size_t *size)
615f21dd 714{
715 //make sure buffer has enough data
0df669a2 716 if (*size < 128) return -1;
615f21dd 717
615f21dd 718 size_t startIdx = 0;
0df669a2 719 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
720
615f21dd 721 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
0df669a2 722 if (errChk == 0) return -2; //preamble not found
615f21dd 723 return (int)startIdx;
724}
1e090a61 725
6c283951 726// ASK/Diphase fc/64 (inverted Biphase)
727// Note: this i s not a demod, this is only a detection
728// the parameter *dest needs to be demoded before call
729int JablotronDemod(uint8_t *dest, size_t *size){
730 //make sure buffer has enough data
731 if (*size < 64) return -1;
732
733 size_t startIdx = 0;
734 // 0xFFFF preamble, 64bits
29ce214c 735 uint8_t preamble[] = {
736 1,1,1,1,
737 1,1,1,1,
738 1,1,1,1,
739 1,1,1,1,
740 0
741 };
6c283951 742
743 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
744 if (errChk == 0) return -4; //preamble not found
29ce214c 745 if (*size != 64) return -3;
6c283951 746
29ce214c 747 uint8_t checkchksum = 0;
6c283951 748 for (int i=16; i < 56; i += 8) {
29ce214c 749 checkchksum += bytebits_to_byte(dest+startIdx+i,8);
6c283951 750 }
29ce214c 751 checkchksum ^= 0x3A;
6c283951 752
29ce214c 753 uint8_t crc = bytebits_to_byte(dest+startIdx+56, 8);
6c283951 754
29ce214c 755 if ( checkchksum != crc ) return -5;
6c283951 756 return (int)startIdx;
757}
758
1e090a61 759// by marshmellow
760// FSK Demod then try to locate an AWID ID
a1d17964 761int AWIDdemodFSK(uint8_t *dest, size_t *size)
1e090a61 762{
a1d17964 763 //make sure buffer has enough data
764 if (*size < 96*50) return -1;
765
766 if (justNoise(dest, *size)) return -2;
1e090a61 767
768 // FSK demodulator
a1d17964 769 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
770 if (*size < 96) return -3; //did we get a good demod?
771
772 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
773 size_t startIdx = 0;
774 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
775 if (errChk == 0) return -4; //preamble not found
776 if (*size != 96) return -5;
777 return (int)startIdx;
1e090a61 778}
779
780// by marshmellow
6426f6ba 781// FSK Demod then try to locate a Farpointe Data (pyramid) ID
a1d17964 782int PyramiddemodFSK(uint8_t *dest, size_t *size)
1e090a61 783{
f3bf15e4 784 //make sure buffer has data
785 if (*size < 128*50) return -5;
a1d17964 786
f3bf15e4 787 //test samples are not just noise
788 if (justNoise(dest, *size)) return -1;
1e090a61 789
f3bf15e4 790 // FSK demodulator
791 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
792 if (*size < 128) return -2; //did we get a good demod?
a1d17964 793
f3bf15e4 794 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
a1d17964 795 size_t startIdx = 0;
796 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
797 if (errChk == 0) return -4; //preamble not found
798 if (*size != 128) return -3;
799 return (int)startIdx;
1e090a61 800}
801
0cbe0cb8 802// find nedap preamble in already demoded data
56bbb25a 803int NedapDemod(uint8_t *dest, size_t *size) {
804 //make sure buffer has data
805 if (*size < 128) return -3;
96faed21 806
56bbb25a 807 size_t startIdx = 0;
15d49e82 808 //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
809 uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0};
56bbb25a 810 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
811 if (errChk == 0) return -4; //preamble not found
56bbb25a 812 return (int) startIdx;
813}
814
fef74fdc 815// by marshmellow
816// to detect a wave that has heavily clipped (clean) samples
cc15a118 817uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
6de43508 818{
6426f6ba 819 bool allArePeaks = true;
6de43508 820 uint16_t cntPeaks=0;
6426f6ba 821 size_t loopEnd = 512+160;
1fbf8956 822 if (loopEnd > size) loopEnd = size;
6426f6ba 823 for (size_t i=160; i<loopEnd; i++){
6de43508 824 if (dest[i]>low && dest[i]<high)
6426f6ba 825 allArePeaks = false;
6de43508 826 else
827 cntPeaks++;
828 }
6426f6ba 829 if (!allArePeaks){
830 if (cntPeaks > 300) return true;
6de43508 831 }
6426f6ba 832 return allArePeaks;
6de43508 833}
2eec55c8 834// by marshmellow
835// to help detect clocks on heavily clipped samples
cc15a118 836// based on count of low to low
837int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
13d77ef9 838{
cc15a118 839 uint8_t fndClk[] = {8,16,32,40,50,64,128};
840 size_t startwave;
6426f6ba 841 size_t i = 100;
cc15a118 842 size_t minClk = 255;
843 // get to first full low to prime loop and skip incomplete first pulse
844 while ((dest[i] < high) && (i < size))
845 ++i;
846 while ((dest[i] > low) && (i < size))
847 ++i;
848
849 // loop through all samples
850 while (i < size) {
851 // measure from low to low
852 while ((dest[i] > low) && (i < size))
853 ++i;
854 startwave= i;
855 while ((dest[i] < high) && (i < size))
856 ++i;
857 while ((dest[i] > low) && (i < size))
858 ++i;
859 //get minimum measured distance
860 if (i-startwave < minClk && i < size)
861 minClk = i - startwave;
13d77ef9 862 }
cc15a118 863 // set clock
a126332a 864 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
cc15a118 865 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
866 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
867 return fndClk[clkCnt];
13d77ef9 868 }
cc15a118 869 return 0;
13d77ef9 870}
871
eb191de6 872// by marshmellow
873// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
874// maybe somehow adjust peak trimming value based on samples to fix?
6de43508 875// return start index of best starting position for that clock and return clock (by reference)
876int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
eb191de6 877{
6e984446 878 size_t i=1;
cc15a118 879 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
880 uint8_t clkEnd = 9;
2eec55c8 881 uint8_t loopCnt = 255; //don't need to loop through entire array...
6426f6ba 882 if (size <= loopCnt+60) return -1; //not enough samples
883 size -= 60; //sometimes there is a strange end wave - filter out this....
6e984446 884 //if we already have a valid clock
885 uint8_t clockFnd=0;
cc15a118 886 for (;i<clkEnd;++i)
887 if (clk[i] == *clock) clockFnd = i;
6e984446 888 //clock found but continue to find best startpos
e0165dcf 889
890 //get high and low peak
891 int peak, low;
2eec55c8 892 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
e0165dcf 893
894 //test for large clean peaks
cc15a118 895 if (!clockFnd){
896 if (DetectCleanAskWave(dest, size, peak, low)==1){
897 int ans = DetectStrongAskClock(dest, size, peak, low);
a126332a 898 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
cc15a118 899 for (i=clkEnd-1; i>0; i--){
900 if (clk[i] == ans) {
901 *clock = ans;
902 //clockFnd = i;
903 return 0; // for strong waves i don't use the 'best start position' yet...
904 //break; //clock found but continue to find best startpos [not yet]
905 }
e0165dcf 906 }
907 }
908 }
2eec55c8 909 uint8_t ii;
910 uint8_t clkCnt, tol = 0;
911 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
912 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
913 size_t errCnt = 0;
914 size_t arrLoc, loopEnd;
6e984446 915
cc15a118 916 if (clockFnd>0) {
917 clkCnt = clockFnd;
918 clkEnd = clockFnd+1;
919 }
920 else clkCnt=1;
921
922 //test each valid clock from smallest to greatest to see which lines up
923 for(; clkCnt < clkEnd; clkCnt++){
fef74fdc 924 if (clk[clkCnt] <= 32){
e0165dcf 925 tol=1;
926 }else{
927 tol=0;
928 }
2767fc02 929 //if no errors allowed - keep start within the first clock
cc15a118 930 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
e0165dcf 931 bestErr[clkCnt]=1000;
6e984446 932 //try lining up the peaks by moving starting point (try first few clocks)
cc15a118 933 for (ii=0; ii < loopCnt; ii++){
2eec55c8 934 if (dest[ii] < peak && dest[ii] > low) continue;
935
936 errCnt=0;
937 // now that we have the first one lined up test rest of wave array
938 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
939 for (i=0; i < loopEnd; ++i){
940 arrLoc = ii + (i * clk[clkCnt]);
941 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
942 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
943 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
944 }else{ //error no peak detected
945 errCnt++;
e0165dcf 946 }
947 }
cc15a118 948 //if we found no errors then we can stop here and a low clock (common clocks)
2eec55c8 949 // this is correct one - return this clock
a126332a 950 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
cc15a118 951 if(errCnt==0 && clkCnt<7) {
952 if (!clockFnd) *clock = clk[clkCnt];
2eec55c8 953 return ii;
954 }
955 //if we found errors see if it is lowest so far and save it as best run
956 if(errCnt<bestErr[clkCnt]){
957 bestErr[clkCnt]=errCnt;
958 bestStart[clkCnt]=ii;
959 }
e0165dcf 960 }
961 }
cc15a118 962 uint8_t iii;
e0165dcf 963 uint8_t best=0;
cc15a118 964 for (iii=1; iii<clkEnd; ++iii){
2eec55c8 965 if (bestErr[iii] < bestErr[best]){
966 if (bestErr[iii] == 0) bestErr[iii]=1;
e0165dcf 967 // current best bit to error ratio vs new bit to error ratio
2eec55c8 968 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
e0165dcf 969 best = iii;
970 }
971 }
a126332a 972 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]);
e0165dcf 973 }
cc15a118 974 if (!clockFnd) *clock = clk[best];
e0165dcf 975 return bestStart[best];
eb191de6 976}
ba1a299c 977
978//by marshmellow
6de43508 979//detect psk clock by reading each phase shift
980// a phase shift is determined by measuring the sample length of each wave
981int DetectPSKClock(uint8_t dest[], size_t size, int clock)
ba1a299c 982{
e0165dcf 983 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
984 uint16_t loopCnt = 4096; //don't need to loop through entire array...
985 if (size == 0) return 0;
6426f6ba 986 if (size<loopCnt) loopCnt = size-20;
e0165dcf 987
988 //if we already have a valid clock quit
989 size_t i=1;
990 for (; i < 8; ++i)
991 if (clk[i] == clock) return clock;
992
993 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
994 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
995 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
996 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
997 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
2eec55c8 998 fc = countFC(dest, size, 0);
999 if (fc!=2 && fc!=4 && fc!=8) return -1;
a126332a 1000 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
e0165dcf 1001
1002 //find first full wave
6426f6ba 1003 for (i=160; i<loopCnt; i++){
e0165dcf 1004 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1005 if (waveStart == 0) {
1006 waveStart = i+1;
6426f6ba 1007 //prnt("DEBUG: waveStart: %d",waveStart);
e0165dcf 1008 } else {
1009 waveEnd = i+1;
6426f6ba 1010 //prnt("DEBUG: waveEnd: %d",waveEnd);
e0165dcf 1011 waveLenCnt = waveEnd-waveStart;
1012 if (waveLenCnt > fc){
1013 firstFullWave = waveStart;
1014 fullWaveLen=waveLenCnt;
1015 break;
1016 }
1017 waveStart=0;
1018 }
1019 }
1020 }
a126332a 1021 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 1022
1023 //test each valid clock from greatest to smallest to see which lines up
1024 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1025 lastClkBit = firstFullWave; //set end of wave as clock align
1026 waveStart = 0;
1027 errCnt=0;
1028 peakcnt=0;
a126332a 1029 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
e0165dcf 1030
1031 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1032 //top edge of wave = start of new wave
1033 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1034 if (waveStart == 0) {
1035 waveStart = i+1;
1036 waveLenCnt=0;
1037 } else { //waveEnd
1038 waveEnd = i+1;
1039 waveLenCnt = waveEnd-waveStart;
1040 if (waveLenCnt > fc){
1041 //if this wave is a phase shift
a126332a 1042 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 1043 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1044 peakcnt++;
1045 lastClkBit+=clk[clkCnt];
1046 } else if (i<lastClkBit+8){
1047 //noise after a phase shift - ignore
1048 } else { //phase shift before supposed to based on clock
1049 errCnt++;
1050 }
1051 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1052 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1053 }
1054 waveStart=i+1;
1055 }
1056 }
1057 }
1058 if (errCnt == 0){
1059 return clk[clkCnt];
1060 }
1061 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1062 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1063 }
1064 //all tested with errors
1065 //return the highest clk with the most peaks found
1066 uint8_t best=7;
1067 for (i=7; i>=1; i--){
1068 if (peaksdet[i] > peaksdet[best]) {
1069 best = i;
1070 }
a126332a 1071 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
e0165dcf 1072 }
1073 return clk[best];
ba1a299c 1074}
1075
6426f6ba 1076int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1077 //find shortest transition from high to low
1078 size_t i = 0;
1079 size_t transition1 = 0;
1080 int lowestTransition = 255;
1081 bool lastWasHigh = false;
1082
1083 //find first valid beginning of a high or low wave
1084 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1085 ++i;
1086 while ((dest[i] < peak && dest[i] > low) && (i < size))
1087 ++i;
1088 lastWasHigh = (dest[i] >= peak);
1089
1090 if (i==size) return 0;
1091 transition1 = i;
1092
1093 for (;i < size; i++) {
1094 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1095 lastWasHigh = (dest[i] >= peak);
1096 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1097 transition1 = i;
1098 }
1099 }
6426f6ba 1100 if (lowestTransition == 255) lowestTransition = 0;
a126332a 1101 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
6426f6ba 1102 return lowestTransition;
1103}
1104
6de43508 1105//by marshmellow
1106//detect nrz clock by reading #peaks vs no peaks(or errors)
1107int DetectNRZClock(uint8_t dest[], size_t size, int clock)
ba1a299c 1108{
2eec55c8 1109 size_t i=0;
1110 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1111 size_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1112 if (size == 0) return 0;
6426f6ba 1113 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1114 //if we already have a valid clock quit
1115 for (; i < 8; ++i)
1116 if (clk[i] == clock) return clock;
1117
1118 //get high and low peak
1119 int peak, low;
2eec55c8 1120 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
e0165dcf 1121
6426f6ba 1122 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
2eec55c8 1123 size_t ii;
e0165dcf 1124 uint8_t clkCnt;
1125 uint8_t tol = 0;
6426f6ba 1126 uint16_t smplCnt = 0;
1127 int16_t peakcnt = 0;
1128 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1129 uint16_t maxPeak = 255;
1130 bool firstpeak = false;
e0165dcf 1131 //test for large clipped waves
1132 for (i=0; i<loopCnt; i++){
1133 if (dest[i] >= peak || dest[i] <= low){
6426f6ba 1134 if (!firstpeak) continue;
1135 smplCnt++;
e0165dcf 1136 } else {
6426f6ba 1137 firstpeak=true;
1138 if (smplCnt > 6 ){
1139 if (maxPeak > smplCnt){
1140 maxPeak = smplCnt;
1141 //prnt("maxPk: %d",maxPeak);
1142 }
1143 peakcnt++;
1144 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1145 smplCnt=0;
e0165dcf 1146 }
e0165dcf 1147 }
1148 }
6426f6ba 1149 bool errBitHigh = 0;
1150 bool bitHigh = 0;
1151 uint8_t ignoreCnt = 0;
1152 uint8_t ignoreWindow = 4;
1153 bool lastPeakHigh = 0;
1154 int lastBit = 0;
e0165dcf 1155 peakcnt=0;
1156 //test each valid clock from smallest to greatest to see which lines up
1157 for(clkCnt=0; clkCnt < 8; ++clkCnt){
6426f6ba 1158 //ignore clocks smaller than smallest peak
1159 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
e0165dcf 1160 //try lining up the peaks by moving starting point (try first 256)
6426f6ba 1161 for (ii=20; ii < loopCnt; ++ii){
e0165dcf 1162 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1163 peakcnt=0;
6426f6ba 1164 bitHigh = false;
1165 ignoreCnt = 0;
1166 lastBit = ii-clk[clkCnt];
1167 //loop through to see if this start location works
1168 for (i = ii; i < size-20; ++i) {
1169 //if we are at a clock bit
1170 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1171 //test high/low
1172 if (dest[i] >= peak || dest[i] <= low) {
1173 //if same peak don't count it
1174 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
e0165dcf 1175 peakcnt++;
6426f6ba 1176 }
1177 lastPeakHigh = (dest[i] >= peak);
1178 bitHigh = true;
1179 errBitHigh = false;
1180 ignoreCnt = ignoreWindow;
1181 lastBit += clk[clkCnt];
1182 } else if (i == lastBit + clk[clkCnt] + tol) {
1183 lastBit += clk[clkCnt];
1184 }
1185 //else if not a clock bit and no peaks
1186 } else if (dest[i] < peak && dest[i] > low){
1187 if (ignoreCnt==0){
1188 bitHigh=false;
1189 if (errBitHigh==true) peakcnt--;
1190 errBitHigh=false;
1191 } else {
1192 ignoreCnt--;
1193 }
1194 // else if not a clock bit but we have a peak
1195 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1196 //error bar found no clock...
1197 errBitHigh=true;
e0165dcf 1198 }
1199 }
1200 if(peakcnt>peaksdet[clkCnt]) {
1201 peaksdet[clkCnt]=peakcnt;
1202 }
1203 }
1204 }
1205 }
1206 int iii=7;
2eec55c8 1207 uint8_t best=0;
e0165dcf 1208 for (iii=7; iii > 0; iii--){
6426f6ba 1209 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1210 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
1211 best = iii;
1212 }
1213 } else if (peaksdet[iii] > peaksdet[best]){
e0165dcf 1214 best = iii;
1215 }
a126332a 1216 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 1217 }
6426f6ba 1218
e0165dcf 1219 return clk[best];
ba1a299c 1220}
1221
04d2721b 1222// by marshmellow
1223// convert psk1 demod to psk2 demod
1224// only transition waves are 1s
1225void psk1TOpsk2(uint8_t *BitStream, size_t size)
1226{
1227 size_t i=1;
1228 uint8_t lastBit=BitStream[0];
1229 for (; i<size; i++){
2767fc02 1230 if (BitStream[i]==7){
7a8a982b 1231 //ignore errors
1232 } else if (lastBit!=BitStream[i]){
04d2721b 1233 lastBit=BitStream[i];
1234 BitStream[i]=1;
1235 } else {
1236 BitStream[i]=0;
1237 }
1238 }
1239 return;
1240}
ba1a299c 1241
3bc66a96 1242// by marshmellow
1243// convert psk2 demod to psk1 demod
1244// from only transition waves are 1s to phase shifts change bit
1245void psk2TOpsk1(uint8_t *BitStream, size_t size)
1246{
712ebfa6 1247 uint8_t phase=0;
1248 for (size_t i=0; i<size; i++){
1249 if (BitStream[i]==1){
3bc66a96 1250 phase ^=1;
1251 }
1252 BitStream[i]=phase;
1253 }
1254 return;
1255}
1256
04d2721b 1257// redesigned by marshmellow adjusted from existing decode functions
1258// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
ba1a299c 1259int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1260{
1261 //26 bit 40134 format (don't know other formats)
57c7b44b 1262 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};
1263 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};
1264 size_t startidx = 0;
1265 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1266 // if didn't find preamble try again inverting
1267 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1268 *invert ^= 1;
1269 }
1270 if (*size != 64 && *size != 224) return -2;
1271 if (*invert==1)
1272 for (size_t i = startidx; i < *size; i++)
1273 bitStream[i] ^= 1;
ba1a299c 1274
57c7b44b 1275 return (int) startidx;
ba1a299c 1276}
1277
05164399 1278// by marshmellow - demodulate NRZ wave - requires a read with strong signal
04d2721b 1279// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
6426f6ba 1280int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
e0165dcf 1281 if (justNoise(dest, *size)) return -1;
1282 *clk = DetectNRZClock(dest, *size, *clk);
1283 if (*clk==0) return -2;
2eec55c8 1284 size_t i, gLen = 4096;
6426f6ba 1285 if (gLen>*size) gLen = *size-20;
e0165dcf 1286 int high, low;
1287 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
6426f6ba 1288
1289 uint8_t bit=0;
1290 //convert wave samples to 1's and 0's
1291 for(i=20; i < *size-20; i++){
1292 if (dest[i] >= high) bit = 1;
1293 if (dest[i] <= low) bit = 0;
1294 dest[i] = bit;
e0165dcf 1295 }
6426f6ba 1296 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1297 size_t lastBit = 0;
1298 size_t numBits = 0;
1299 for(i=21; i < *size-20; i++) {
1300 //if transition detected or large number of same bits - store the passed bits
1301 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1302 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1303 numBits += (i - lastBit + (*clk/4)) / *clk;
1304 lastBit = i-1;
e0165dcf 1305 }
e0165dcf 1306 }
6426f6ba 1307 *size = numBits;
1308 return 0;
ba1a299c 1309}
1310
1e090a61 1311//by marshmellow
03e6bb4a 1312//detects the bit clock for FSK given the high and low Field Clocks
1313uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1e090a61 1314{
e0165dcf 1315 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1316 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1317 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1318 uint8_t rfLensFnd = 0;
2eec55c8 1319 uint8_t lastFCcnt = 0;
1320 uint16_t fcCounter = 0;
e0165dcf 1321 uint16_t rfCounter = 0;
1322 uint8_t firstBitFnd = 0;
1323 size_t i;
1324 if (size == 0) return 0;
1325
6426f6ba 1326 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
e0165dcf 1327 rfLensFnd=0;
1328 fcCounter=0;
1329 rfCounter=0;
1330 firstBitFnd=0;
1331 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
6426f6ba 1332 // prime i to first peak / up transition
1333 for (i = 160; i < size-20; i++)
e0165dcf 1334 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1335 break;
1336
6426f6ba 1337 for (; i < size-20; i++){
2eec55c8 1338 fcCounter++;
1339 rfCounter++;
1340
1341 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1342 continue;
1343 // else new peak
1344 // if we got less than the small fc + tolerance then set it to the small fc
1345 if (fcCounter < fcLow+fcTol)
1346 fcCounter = fcLow;
1347 else //set it to the large fc
1348 fcCounter = fcHigh;
1349
1350 //look for bit clock (rf/xx)
1351 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1352 //not the same size as the last wave - start of new bit sequence
1353 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1354 for (int ii=0; ii<15; ii++){
6426f6ba 1355 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
2eec55c8 1356 rfCnts[ii]++;
1357 rfCounter = 0;
1358 break;
e0165dcf 1359 }
e0165dcf 1360 }
2eec55c8 1361 if (rfCounter > 0 && rfLensFnd < 15){
1362 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1363 rfCnts[rfLensFnd]++;
1364 rfLens[rfLensFnd++] = rfCounter;
1365 }
1366 } else {
1367 firstBitFnd++;
e0165dcf 1368 }
2eec55c8 1369 rfCounter=0;
1370 lastFCcnt=fcCounter;
e0165dcf 1371 }
2eec55c8 1372 fcCounter=0;
e0165dcf 1373 }
1374 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1375
1376 for (i=0; i<15; i++){
e0165dcf 1377 //get highest 2 RF values (might need to get more values to compare or compare all?)
1378 if (rfCnts[i]>rfCnts[rfHighest]){
1379 rfHighest3=rfHighest2;
1380 rfHighest2=rfHighest;
1381 rfHighest=i;
1382 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1383 rfHighest3=rfHighest2;
1384 rfHighest2=i;
1385 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1386 rfHighest3=i;
1387 }
a126332a 1388 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
e0165dcf 1389 }
1390 // set allowed clock remainder tolerance to be 1 large field clock length+1
1391 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1392 uint8_t tol1 = fcHigh+1;
1393
a126332a 1394 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
e0165dcf 1395
1396 // loop to find the highest clock that has a remainder less than the tolerance
1397 // compare samples counted divided by
6426f6ba 1398 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
e0165dcf 1399 int ii=7;
6426f6ba 1400 for (; ii>=2; ii--){
e0165dcf 1401 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1402 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1403 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
a126332a 1404 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
e0165dcf 1405 break;
1406 }
1407 }
1408 }
1409 }
1410
1411 if (ii<0) return 0; // oops we went too far
1412
1413 return clk[ii];
03e6bb4a 1414}
1e090a61 1415
03e6bb4a 1416//by marshmellow
1417//countFC is to detect the field clock lengths.
1418//counts and returns the 2 most common wave lengths
6de43508 1419//mainly used for FSK field clock detection
2eec55c8 1420uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
03e6bb4a 1421{
6426f6ba 1422 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1423 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
e0165dcf 1424 uint8_t fcLensFnd = 0;
1425 uint8_t lastFCcnt=0;
2eec55c8 1426 uint8_t fcCounter = 0;
e0165dcf 1427 size_t i;
1428 if (size == 0) return 0;
1429
1430 // prime i to first up transition
6426f6ba 1431 for (i = 160; i < size-20; i++)
e0165dcf 1432 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1433 break;
1434
6426f6ba 1435 for (; i < size-20; i++){
e0165dcf 1436 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1437 // new up transition
1438 fcCounter++;
2eec55c8 1439 if (fskAdj){
1440 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1441 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1442 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1443 if ((fcCounter==9) || fcCounter==4) fcCounter++;
e0165dcf 1444 // save last field clock count (fc/xx)
2eec55c8 1445 lastFCcnt = fcCounter;
1446 }
e0165dcf 1447 // find which fcLens to save it to:
6426f6ba 1448 for (int ii=0; ii<15; ii++){
e0165dcf 1449 if (fcLens[ii]==fcCounter){
1450 fcCnts[ii]++;
1451 fcCounter=0;
1452 break;
1453 }
1454 }
6426f6ba 1455 if (fcCounter>0 && fcLensFnd<15){
e0165dcf 1456 //add new fc length
1457 fcCnts[fcLensFnd]++;
1458 fcLens[fcLensFnd++]=fcCounter;
1459 }
1460 fcCounter=0;
1461 } else {
1462 // count sample
1463 fcCounter++;
1464 }
1465 }
1466
6426f6ba 1467 uint8_t best1=14, best2=14, best3=14;
e0165dcf 1468 uint16_t maxCnt1=0;
1469 // go through fclens and find which ones are bigest 2
6426f6ba 1470 for (i=0; i<15; i++){
e0165dcf 1471 // get the 3 best FC values
1472 if (fcCnts[i]>maxCnt1) {
1473 best3=best2;
1474 best2=best1;
1475 maxCnt1=fcCnts[i];
1476 best1=i;
1477 } else if(fcCnts[i]>fcCnts[best2]){
1478 best3=best2;
1479 best2=i;
1480 } else if(fcCnts[i]>fcCnts[best3]){
1481 best3=i;
1482 }
a126332a 1483 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 1484 }
6426f6ba 1485 if (fcLens[best1]==0) return 0;
e0165dcf 1486 uint8_t fcH=0, fcL=0;
1487 if (fcLens[best1]>fcLens[best2]){
1488 fcH=fcLens[best1];
1489 fcL=fcLens[best2];
1490 } else{
1491 fcH=fcLens[best2];
1492 fcL=fcLens[best1];
1493 }
a126332a 1494 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1495 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]);
1496 return 0; //lots of waves not psk or fsk
1497 }
e0165dcf 1498 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1499
1500 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
2eec55c8 1501 if (fskAdj) return fcs;
1502 return fcLens[best1];
6de43508 1503}
1504
1505//by marshmellow - demodulate PSK1 wave
1506//uses wave lengths (# Samples)
1507int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1508{
e0165dcf 1509 if (size == 0) return -1;
2eec55c8 1510 uint16_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1511 if (*size<loopCnt) loopCnt = *size;
1512
6426f6ba 1513 size_t numBits=0;
e0165dcf 1514 uint8_t curPhase = *invert;
1515 size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1516 uint8_t fc=0, fullWaveLen=0, tol=1;
1517 uint16_t errCnt=0, waveLenCnt=0;
2eec55c8 1518 fc = countFC(dest, *size, 0);
e0165dcf 1519 if (fc!=2 && fc!=4 && fc!=8) return -1;
1520 //PrintAndLog("DEBUG: FC: %d",fc);
1521 *clock = DetectPSKClock(dest, *size, *clock);
2eec55c8 1522 if (*clock == 0) return -1;
e0165dcf 1523 int avgWaveVal=0, lastAvgWaveVal=0;
1524 //find first phase shift
1525 for (i=0; i<loopCnt; i++){
1526 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1527 waveEnd = i+1;
1528 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1529 waveLenCnt = waveEnd-waveStart;
6426f6ba 1530 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack
e0165dcf 1531 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1532 firstFullWave = waveStart;
1533 fullWaveLen=waveLenCnt;
1534 //if average wave value is > graph 0 then it is an up wave or a 1
2eec55c8 1535 if (lastAvgWaveVal > 123) curPhase ^= 1; //fudge graph 0 a little 123 vs 128
e0165dcf 1536 break;
1537 }
1538 waveStart = i+1;
1539 avgWaveVal = 0;
1540 }
2eec55c8 1541 avgWaveVal += dest[i+2];
e0165dcf 1542 }
6426f6ba 1543 if (firstFullWave == 0) {
1544 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1545 // so skip a little to ensure we are past any Start Signal
1546 firstFullWave = 160;
1547 memset(dest, curPhase, firstFullWave / *clock);
1548 } else {
1549 memset(dest, curPhase^1, firstFullWave / *clock);
1550 }
1551 //advance bits
1552 numBits += (firstFullWave / *clock);
1553 //set start of wave as clock align
1554 lastClkBit = firstFullWave;
7fa7e812 1555 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
1556 if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
e0165dcf 1557 waveStart = 0;
e0165dcf 1558 dest[numBits++] = curPhase; //set first read bit
2eec55c8 1559 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
e0165dcf 1560 //top edge of wave = start of new wave
1561 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1562 if (waveStart == 0) {
1563 waveStart = i+1;
2eec55c8 1564 waveLenCnt = 0;
e0165dcf 1565 avgWaveVal = dest[i+1];
1566 } else { //waveEnd
1567 waveEnd = i+1;
1568 waveLenCnt = waveEnd-waveStart;
1569 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1570 if (waveLenCnt > fc){
1571 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
2eec55c8 1572 //this wave is a phase shift
e0165dcf 1573 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1574 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
2eec55c8 1575 curPhase ^= 1;
e0165dcf 1576 dest[numBits++] = curPhase;
1577 lastClkBit += *clock;
2eec55c8 1578 } else if (i < lastClkBit+10+fc){
e0165dcf 1579 //noise after a phase shift - ignore
1580 } else { //phase shift before supposed to based on clock
1581 errCnt++;
2767fc02 1582 dest[numBits++] = 7;
e0165dcf 1583 }
1584 } else if (i+1 > lastClkBit + *clock + tol + fc){
1585 lastClkBit += *clock; //no phase shift but clock bit
1586 dest[numBits++] = curPhase;
1587 }
2eec55c8 1588 avgWaveVal = 0;
1589 waveStart = i+1;
e0165dcf 1590 }
1591 }
2eec55c8 1592 avgWaveVal += dest[i+1];
e0165dcf 1593 }
1594 *size = numBits;
1595 return errCnt;
6de43508 1596}
05164399 1597
1598//by marshmellow
1599//attempt to identify a Sequence Terminator in ASK modulated raw wave
1600bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1601 size_t bufsize = *size;
1602 //need to loop through all samples and identify our clock, look for the ST pattern
1603 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1604 int clk = 0;
1605 int tol = 0;
1606 int i, j, skip, start, end, low, high, minClk, waveStart;
1607 bool complete = false;
1608 int tmpbuff[bufsize / 64];
1609 int waveLen[bufsize / 64];
1610 size_t testsize = (bufsize < 512) ? bufsize : 512;
1611 int phaseoff = 0;
1612 high = low = 128;
1613 memset(tmpbuff, 0, sizeof(tmpbuff));
1614
1615 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1616 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1617 return false; //just noise
1618 }
1619 i = 0;
1620 j = 0;
1621 minClk = 255;
1622 // get to first full low to prime loop and skip incomplete first pulse
1623 while ((buffer[i] < high) && (i < bufsize))
1624 ++i;
1625 while ((buffer[i] > low) && (i < bufsize))
1626 ++i;
1627 skip = i;
1628
1629 // populate tmpbuff buffer with pulse lengths
1630 while (i < bufsize) {
1631 // measure from low to low
1632 while ((buffer[i] > low) && (i < bufsize))
1633 ++i;
1634 start= i;
1635 while ((buffer[i] < high) && (i < bufsize))
1636 ++i;
1637 //first high point for this wave
1638 waveStart = i;
1639 while ((buffer[i] > low) && (i < bufsize))
1640 ++i;
1641 if (j >= (bufsize/64)) {
1642 break;
1643 }
1644 waveLen[j] = i - waveStart; //first high to first low
1645 tmpbuff[j++] = i - start;
1646 if (i-start < minClk && i < bufsize) {
1647 minClk = i - start;
1648 }
1649 }
1650 // set clock - might be able to get this externally and remove this work...
1651 if (!clk) {
1652 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1653 tol = fndClk[clkCnt]/8;
1654 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1655 clk=fndClk[clkCnt];
1656 break;
1657 }
1658 }
1659 // clock not found - ERROR
1660 if (!clk) {
1661 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1662 return false;
1663 }
1664 } else tol = clk/8;
1665
1666 *foundclock = clk;
1667
1668 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1669 start = -1;
1670 for (i = 0; i < j - 4; ++i) {
1671 skip += tmpbuff[i];
1672 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1673 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
1674 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
1675 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1676 start = i + 3;
1677 break;
1678 }
1679 }
1680 }
1681 }
1682 }
1683 // first ST not found - ERROR
1684 if (start < 0) {
1685 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1686 return false;
1687 }
1688 if (waveLen[i+2] > clk*1+tol)
1689 phaseoff = 0;
1690 else
1691 phaseoff = clk/2;
1692
1693 // skip over the remainder of ST
1694 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1695
1696 // now do it again to find the end
1697 end = skip;
1698 for (i += 3; i < j - 4; ++i) {
1699 end += tmpbuff[i];
1700 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol) { //1 to 2 clocks depending on 2 bits prior
1701 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
1702 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
1703 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
1704 complete = true;
1705 break;
1706 }
1707 }
1708 }
1709 }
1710 }
1711 end -= phaseoff;
1712 //didn't find second ST - ERROR
1713 if (!complete) {
1714 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1715 return false;
1716 }
1717 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);
1718 //now begin to trim out ST so we can use normal demod cmds
1719 start = skip;
1720 size_t datalen = end - start;
1721 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1722 if (datalen % clk > clk/8) {
1723 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1724 return false;
1725 } else {
1726 // padd the amount off - could be problematic... but shouldn't happen often
1727 datalen += datalen % clk;
1728 }
1729 // if datalen is less than one t55xx block - ERROR
1730 if (datalen/clk < 8*4) {
1731 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1732 return false;
1733 }
1734 size_t dataloc = start;
1735 size_t newloc = 0;
1736 i=0;
1737 // warning - overwriting buffer given with raw wave data with ST removed...
1738 while ( dataloc < bufsize-(clk/2) ) {
7fa7e812 1739 //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 1740 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1741 for(i=0; i < clk/2-tol; ++i) {
1742 buffer[dataloc+i] = high+5;
1743 }
1744 }
1745 for (i=0; i<datalen; ++i) {
1746 if (i+newloc < bufsize) {
1747 if (i+newloc < dataloc)
1748 buffer[i+newloc] = buffer[dataloc];
1749
1750 dataloc++;
1751 }
1752 }
1753 newloc += i;
7fa7e812 1754 //skip next ST - we just assume it will be there from now on...
05164399 1755 dataloc += clk*4;
1756 }
1757 *size = newloc;
1758 return true;
1759}
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