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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"
d1869c33 13#include <string.h>
6fe5c94b 14
d1869c33 15//to allow debug print calls when used not on device
6fe5c94b 16void dummy(char *fmt, ...){}
17
18#ifndef ON_DEVICE
19#include "ui.h"
709665b5 20#include "cmdparser.h"
21#include "cmddata.h"
6fe5c94b 22#define prnt PrintAndLog
23#else
709665b5 24 uint8_t g_debugMode=0;
6fe5c94b 25#define prnt dummy
26#endif
6fe5c94b 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 }
e39a92bb 65 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
a1d17964 66 return (ans == pType);
67}
68
709665b5 69// by marshmellow
70// takes a array of binary values, start position, length of bits per parity (includes parity bit),
88e85bde 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)
709665b5 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;
e39a92bb 76 for (int word = 0; word < (bLen); word+=pLen) {
77 for (int bit=0; bit < pLen; bit++) {
709665b5 78 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
79 BitStream[j++] = (BitStream[startIdx+word+bit]);
80 }
e88096ba 81 if (word+pLen > bLen) break;
e39a92bb 82
709665b5 83 j--; // overwrite parity with next data
84 // if parity fails then return 0
88e85bde 85 switch (pType) {
29435274 86 case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
87 case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
88 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
709665b5 89 }
90 bitCnt+=(pLen-1);
91 parityWd = 0;
92 }
93 // if we got here then all the parities passed
94 //return ID start index and size
95 return bitCnt;
96}
97
98// by marshmellow
99// takes a array of binary values, length of bits per parity (includes parity bit),
88e85bde 100// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
101// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
709665b5 102size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
103{
104 uint32_t parityWd = 0;
105 size_t j = 0, bitCnt = 0;
106 for (int word = 0; word < sourceLen; word+=pLen-1) {
107 for (int bit=0; bit < pLen-1; bit++){
108 parityWd = (parityWd << 1) | BitSource[word+bit];
109 dest[j++] = (BitSource[word+bit]);
110 }
111 // if parity fails then return 0
88e85bde 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;
709665b5 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;
130 for(int i = 0 ; i < numbits ; i++)
131 {
132 num = (num << 1) | (*src);
133 src++;
134 }
135 return num;
136}
137
138//least significant bit first
139uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
140{
141 uint32_t num = 0;
142 for(int i = 0 ; i < numbits ; i++)
143 {
144 num = (num << 1) | *(src + (numbits-(i+1)));
145 }
146 return num;
147}
148
a1d17964 149//by marshmellow
2147c307 150//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
a1d17964 151uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
152{
e88096ba 153 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
154}
155
156// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
157// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
158bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
59f726c9 159 // Sanity check. If preamble length is bigger than bitstream length.
e88096ba 160 if ( *size <= pLen ) return false;
59f726c9 161
e88096ba 162 uint8_t foundCnt = 0;
163 for (size_t idx = 0; idx < *size - pLen; idx++) {
164 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
e0165dcf 165 //first index found
166 foundCnt++;
e88096ba 167 if (foundCnt == 1) {
168 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
e0165dcf 169 *startIdx = idx;
e88096ba 170 if (findone) return true;
171 } else if (foundCnt == 2) {
e0165dcf 172 *size = idx - *startIdx;
e88096ba 173 return true;
e0165dcf 174 }
175 }
176 }
4c6ccc2b 177 return false;
178}
179
34ff8985 180// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
181size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
182 size_t i = 0;
183 size_t waveSizeCnt = 0;
184 uint8_t thresholdCnt = 0;
185 bool isAboveThreshold = dest[i++] >= threshold_value;
186 for (; i < size-20; i++ ) {
187 if(dest[i] < threshold_value && isAboveThreshold) {
188 thresholdCnt++;
189 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
190 isAboveThreshold = false;
191 waveSizeCnt = 0;
192 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
193 thresholdCnt++;
194 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
195 isAboveThreshold = true;
196 waveSizeCnt = 0;
197 } else {
198 waveSizeCnt++;
199 }
200 if (thresholdCnt > 10) break;
201 }
202 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
203 return i;
204}
205
2147c307 206//by marshmellow
207//takes 1s and 0s and searches for EM410x format - output EM ID
208uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
209{
e88096ba 210 //sanity checks
211 if (*size < 64) return 0;
2767fc02 212 if (BitStream[1]>1) return 0; //allow only 1s and 0s
213
e0165dcf 214 // 111111111 bit pattern represent start of frame
215 // include 0 in front to help get start pos
216 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
e0165dcf 217 uint8_t errChk = 0;
e88096ba 218 uint8_t FmtLen = 10; // sets of 4 bits = end data
e0165dcf 219 *startIdx = 0;
220 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
b1ee7eed 221 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
222 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
e88096ba 223
224 //skip last 4bit parity row for simplicity
225 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
226 if (*size == 40) { // std em410x format
227 *hi = 0;
228 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
229 } else if (*size == 88) { // long em format
230 *hi = (bytebits_to_byte(BitStream, 24));
231 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
232 } else {
233 return 0;
e0165dcf 234 }
e88096ba 235 return 1;
2147c307 236}
237
fef74fdc 238//by marshmellow
239//demodulates strong heavily clipped samples
23f0a7d8 240int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
241{
242 size_t bitCnt=0, smplCnt=0, errCnt=0;
243 uint8_t waveHigh = 0;
23f0a7d8 244 for (size_t i=0; i < *size; i++){
245 if (BinStream[i] >= high && waveHigh){
246 smplCnt++;
247 } else if (BinStream[i] <= low && !waveHigh){
248 smplCnt++;
249 } else { //transition
250 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
251 if (smplCnt > clk-(clk/4)-1) { //full clock
252 if (smplCnt > clk + (clk/4)+1) { //too many samples
253 errCnt++;
d1869c33 254 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
2767fc02 255 BinStream[bitCnt++]=7;
23f0a7d8 256 } else if (waveHigh) {
257 BinStream[bitCnt++] = invert;
258 BinStream[bitCnt++] = invert;
259 } else if (!waveHigh) {
260 BinStream[bitCnt++] = invert ^ 1;
261 BinStream[bitCnt++] = invert ^ 1;
262 }
263 waveHigh ^= 1;
264 smplCnt = 0;
265 } else if (smplCnt > (clk/2) - (clk/4)-1) {
266 if (waveHigh) {
267 BinStream[bitCnt++] = invert;
268 } else if (!waveHigh) {
269 BinStream[bitCnt++] = invert ^ 1;
270 }
271 waveHigh ^= 1;
272 smplCnt = 0;
273 } else if (!bitCnt) {
274 //first bit
275 waveHigh = (BinStream[i] >= high);
276 smplCnt = 1;
277 } else {
278 smplCnt++;
279 //transition bit oops
280 }
281 } else { //haven't hit new high or new low yet
282 smplCnt++;
283 }
284 }
285 }
286 *size = bitCnt;
287 return errCnt;
288}
289
eb191de6 290//by marshmellow
fac69c3d 291//amplify based on ask edge detection
fef74fdc 292void askAmp(uint8_t *BitStream, size_t size)
293{
16ea2b8c 294 uint8_t Last = 128;
fef74fdc 295 for(size_t i = 1; i<size; i++){
296 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
16ea2b8c 297 Last = 255;
298 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
299 Last = 0;
300
301 BitStream[i-1] = Last;
fef74fdc 302 }
303 return;
304}
01d0f8ae 305
fef74fdc 306//by marshmellow
307//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
308int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
eb191de6 309{
fef74fdc 310 if (*size==0) return -1;
6e984446 311 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
2eec55c8 312 if (*clk==0 || start < 0) return -3;
fef74fdc 313 if (*invert != 1) *invert = 0;
314 if (amp==1) askAmp(BinStream, *size);
01d0f8ae 315 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
fef74fdc 316
2eec55c8 317 uint8_t initLoopMax = 255;
318 if (initLoopMax > *size) initLoopMax = *size;
ba1a299c 319 // Detect high and lows
fef74fdc 320 //25% clip in case highs and lows aren't clipped [marshmellow]
2eec55c8 321 int high, low;
fef74fdc 322 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
323 return -2; //just noise
ba1a299c 324
fef74fdc 325 size_t errCnt = 0;
23f0a7d8 326 // if clean clipped waves detected run alternate demod
327 if (DetectCleanAskWave(BinStream, *size, high, low)) {
d1869c33 328 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
fef74fdc 329 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
330 if (askType) //askman
331 return manrawdecode(BinStream, size, 0);
332 else //askraw
333 return errCnt;
23f0a7d8 334 }
d1869c33 335 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
23f0a7d8 336
d1869c33 337 int lastBit; //set first clock check - can go negative
fef74fdc 338 size_t i, bitnum = 0; //output counter
339 uint8_t midBit = 0;
2eec55c8 340 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
d1869c33 341 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
342 size_t MaxBits = 3072; //max bits to collect
6e984446 343 lastBit = start - *clk;
fef74fdc 344
6e984446 345 for (i = start; i < *size; ++i) {
fef74fdc 346 if (i-lastBit >= *clk-tol){
347 if (BinStream[i] >= high) {
348 BinStream[bitnum++] = *invert;
349 } else if (BinStream[i] <= low) {
350 BinStream[bitnum++] = *invert ^ 1;
351 } else if (i-lastBit >= *clk+tol) {
352 if (bitnum > 0) {
d1869c33 353 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
fef74fdc 354 BinStream[bitnum++]=7;
355 errCnt++;
356 }
357 } else { //in tolerance - looking for peak
358 continue;
359 }
360 midBit = 0;
2eec55c8 361 lastBit += *clk;
fef74fdc 362 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
363 if (BinStream[i] >= high) {
364 BinStream[bitnum++] = *invert;
365 } else if (BinStream[i] <= low) {
366 BinStream[bitnum++] = *invert ^ 1;
367 } else if (i-lastBit >= *clk/2+tol) {
368 BinStream[bitnum] = BinStream[bitnum-1];
369 bitnum++;
370 } else { //in tolerance - looking for peak
371 continue;
372 }
373 midBit = 1;
2eec55c8 374 }
375 if (bitnum >= MaxBits) break;
ba1a299c 376 }
2eec55c8 377 *size = bitnum;
6e984446 378 return errCnt;
eb191de6 379}
380
381//by marshmellow
382//take 10 and 01 and manchester decode
383//run through 2 times and take least errCnt
fef74fdc 384int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
eb191de6 385{
13d77ef9 386 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
387 size_t i, ii;
388 uint16_t bestErr = 1000, bestRun = 0;
fef74fdc 389 if (*size < 16) return -1;
2767fc02 390 //find correct start position [alignment]
13d77ef9 391 for (ii=0;ii<2;++ii){
fef74fdc 392 for (i=ii; i<*size-3; i+=2)
2eec55c8 393 if (BitStream[i]==BitStream[i+1])
ba1a299c 394 errCnt++;
2eec55c8 395
ba1a299c 396 if (bestErr>errCnt){
397 bestErr=errCnt;
398 bestRun=ii;
399 }
400 errCnt=0;
401 }
2767fc02 402 //decode
fef74fdc 403 for (i=bestRun; i < *size-3; i+=2){
23f0a7d8 404 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
fef74fdc 405 BitStream[bitnum++]=invert;
23f0a7d8 406 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
fef74fdc 407 BitStream[bitnum++]=invert^1;
23f0a7d8 408 } else {
2767fc02 409 BitStream[bitnum++]=7;
ba1a299c 410 }
23f0a7d8 411 if(bitnum>MaxBits) break;
ba1a299c 412 }
23f0a7d8 413 *size=bitnum;
2eec55c8 414 return bestErr;
f822a063 415}
416
3606ac0a 417uint32_t manchesterEncode2Bytes(uint16_t datain) {
418 uint32_t output = 0;
419 uint8_t curBit = 0;
420 for (uint8_t i=0; i<16; i++) {
421 curBit = (datain >> (15-i) & 1);
422 output |= (1<<(((15-i)*2)+curBit));
423 }
424 return output;
425}
426
fef74fdc 427//by marshmellow
428//encode binary data into binary manchester
429int ManchesterEncode(uint8_t *BitStream, size_t size)
430{
431 size_t modIdx=20000, i=0;
432 if (size>modIdx) return -1;
433 for (size_t idx=0; idx < size; idx++){
434 BitStream[idx+modIdx++] = BitStream[idx];
435 BitStream[idx+modIdx++] = BitStream[idx]^1;
436 }
437 for (; i<(size*2); i++){
438 BitStream[i] = BitStream[i+20000];
439 }
440 return i;
441}
442
f822a063 443//by marshmellow
2147c307 444//take 01 or 10 = 1 and 11 or 00 = 0
445//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
13d77ef9 446//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1e090a61 447int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
f822a063 448{
2eec55c8 449 uint16_t bitnum = 0;
450 uint16_t errCnt = 0;
451 size_t i = offset;
2147c307 452 uint16_t MaxBits=512;
453 //if not enough samples - error
454 if (*size < 51) return -1;
455 //check for phase change faults - skip one sample if faulty
456 uint8_t offsetA = 1, offsetB = 1;
457 for (; i<48; i+=2){
458 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
459 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
460 }
461 if (!offsetA && offsetB) offset++;
462 for (i=offset; i<*size-3; i+=2){
463 //check for phase error
13d77ef9 464 if (BitStream[i+1]==BitStream[i+2]) {
2767fc02 465 BitStream[bitnum++]=7;
2147c307 466 errCnt++;
467 }
ba1a299c 468 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1e090a61 469 BitStream[bitnum++]=1^invert;
ba1a299c 470 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1e090a61 471 BitStream[bitnum++]=invert;
ba1a299c 472 } else {
2767fc02 473 BitStream[bitnum++]=7;
ba1a299c 474 errCnt++;
475 }
6de43508 476 if(bitnum>MaxBits) break;
ba1a299c 477 }
478 *size=bitnum;
479 return errCnt;
eb191de6 480}
481
fef74fdc 482// by marshmellow
11081e04 483// demod gProxIIDemod
484// error returns as -x
485// success returns start position in BitStream
486// BitStream must contain previously askrawdemod and biphasedemoded data
487int gProxII_Demod(uint8_t BitStream[], size_t *size)
488{
489 size_t startIdx=0;
490 uint8_t preamble[] = {1,1,1,1,1,0};
491
492 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
493 if (errChk == 0) return -3; //preamble not found
494 if (*size != 96) return -2; //should have found 96 bits
495 //check first 6 spacer bits to verify format
496 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
497 //confirmed proper separator bits found
498 //return start position
499 return (int) startIdx;
500 }
cf194819 501 return -5; //spacer bits not found - not a valid gproxII
11081e04 502}
503
cf194819 504//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
f822a063 505size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
eb191de6 506{
2eec55c8 507 size_t last_transition = 0;
508 size_t idx = 1;
ba1a299c 509 if (fchigh==0) fchigh=10;
510 if (fclow==0) fclow=8;
84871873 511 //set the threshold close to 0 (graph) or 128 std to avoid static
512 uint8_t threshold_value = 123;
f4eadf8a 513 size_t preLastSample = 0;
514 size_t LastSample = 0;
515 size_t currSample = 0;
c85858f5 516 if ( size < 1024 ) return 0; // not enough samples
517
34ff8985 518 //find start of modulating data in trace
519 idx = findModStart(dest, size, threshold_value, fchigh);
ba1a299c 520
521 // Need to threshold first sample
c85858f5 522 if(dest[idx] < threshold_value) dest[0] = 0;
ba1a299c 523 else dest[0] = 1;
c85858f5 524 idx++;
525
ba1a299c 526 size_t numBits = 0;
527 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
63744b56 528 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
ba1a299c 529 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
cf194819 530 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
c85858f5 531 for(; idx < size-20; idx++) {
ba1a299c 532 // threshold current value
533
534 if (dest[idx] < threshold_value) dest[idx] = 0;
535 else dest[idx] = 1;
536
537 // Check for 0->1 transition
cf194819 538 if (dest[idx-1] < dest[idx]) {
f4eadf8a 539 preLastSample = LastSample;
540 LastSample = currSample;
541 currSample = idx-last_transition;
cf194819 542 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
ba1a299c 543 //do nothing with extra garbage
cf194819 544 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
545 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
c85858f5 546 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
cf194819 547 dest[numBits-1]=1;
f4eadf8a 548 }
2eec55c8 549 dest[numBits++]=1;
f4eadf8a 550
c85858f5 551 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
552 //do nothing with beginning garbage and reset.. should be rare..
553 numBits = 0;
cf194819 554 } 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)
f4eadf8a 555 dest[numBits++]=1;
cf194819 556 } else { //9+ = 10 sample waves (or 6+ = 7)
2eec55c8 557 dest[numBits++]=0;
ba1a299c 558 }
559 last_transition = idx;
ba1a299c 560 }
561 }
562 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
eb191de6 563}
564
ba1a299c 565//translate 11111100000 to 10
cf194819 566//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
2eec55c8 567size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
e0165dcf 568 uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 569{
ba1a299c 570 uint8_t lastval=dest[0];
2eec55c8 571 size_t idx=0;
ba1a299c 572 size_t numBits=0;
573 uint32_t n=1;
ba1a299c 574 for( idx=1; idx < size; idx++) {
13d77ef9 575 n++;
cf194819 576 if (dest[idx]==lastval) continue; //skip until we hit a transition
2eec55c8 577
cf194819 578 //find out how many bits (n) we collected
ba1a299c 579 //if lastval was 1, we have a 1->0 crossing
13d77ef9 580 if (dest[idx-1]==1) {
6fe5c94b 581 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 582 } else {// 0->1 crossing
75cbbe9a 583 n = (n * fchigh + rfLen/2) / rfLen;
ba1a299c 584 }
585 if (n == 0) n = 1;
586
cf194819 587 //add to our destination the bits we collected
2eec55c8 588 memset(dest+numBits, dest[idx-1]^invert , n);
589 numBits += n;
ba1a299c 590 n=0;
591 lastval=dest[idx];
592 }//end for
13d77ef9 593 // if valid extra bits at the end were all the same frequency - add them in
75cbbe9a 594 if (n > rfLen/fchigh) {
13d77ef9 595 if (dest[idx-2]==1) {
75cbbe9a 596 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 597 } else {
75cbbe9a 598 n = (n * fchigh + rfLen/2) / rfLen;
13d77ef9 599 }
2eec55c8 600 memset(dest+numBits, dest[idx-1]^invert , n);
13d77ef9 601 numBits += n;
602 }
ba1a299c 603 return numBits;
eb191de6 604}
6fe5c94b 605
eb191de6 606//by marshmellow (from holiman's base)
607// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
f822a063 608int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 609{
ba1a299c 610 // FSK demodulator
611 size = fsk_wave_demod(dest, size, fchigh, fclow);
2eec55c8 612 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
ba1a299c 613 return size;
eb191de6 614}
a1d17964 615
eb191de6 616// loop to get raw HID waveform then FSK demodulate the TAG ID from it
ec75f5c1 617int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
eb191de6 618{
e0165dcf 619 if (justNoise(dest, *size)) return -1;
620
621 size_t numStart=0, size2=*size, startIdx=0;
622 // FSK demodulator
623 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
2eec55c8 624 if (*size < 96*2) return -2;
e0165dcf 625 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
626 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
627 // find bitstring in array
628 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
629 if (errChk == 0) return -3; //preamble not found
630
631 numStart = startIdx + sizeof(preamble);
632 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
633 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
634 if (dest[idx] == dest[idx+1]){
635 return -4; //not manchester data
636 }
637 *hi2 = (*hi2<<1)|(*hi>>31);
638 *hi = (*hi<<1)|(*lo>>31);
639 //Then, shift in a 0 or one into low
640 if (dest[idx] && !dest[idx+1]) // 1 0
641 *lo=(*lo<<1)|1;
642 else // 0 1
643 *lo=(*lo<<1)|0;
644 }
645 return (int)startIdx;
eb191de6 646}
647
ec75f5c1 648// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
a1d17964 649int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
ec75f5c1 650{
a1d17964 651 if (justNoise(dest, *size)) return -1;
652
653 size_t numStart=0, size2=*size, startIdx=0;
ec75f5c1 654 // FSK demodulator
a1d17964 655 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
656 if (*size < 96) return -2;
ec75f5c1 657
a1d17964 658 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
659 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
660
661 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
662 if (errChk == 0) return -3; //preamble not found
663
664 numStart = startIdx + sizeof(preamble);
665 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
666 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
667 if (dest[idx] == dest[idx+1])
668 return -4; //not manchester data
669 *hi2 = (*hi2<<1)|(*hi>>31);
670 *hi = (*hi<<1)|(*lo>>31);
671 //Then, shift in a 0 or one into low
672 if (dest[idx] && !dest[idx+1]) // 1 0
673 *lo=(*lo<<1)|1;
674 else // 0 1
675 *lo=(*lo<<1)|0;
ec75f5c1 676 }
a1d17964 677 return (int)startIdx;
ec75f5c1 678}
679
eb191de6 680int IOdemodFSK(uint8_t *dest, size_t size)
681{
a1d17964 682 if (justNoise(dest, size)) return -1;
ba1a299c 683 //make sure buffer has data
a1d17964 684 if (size < 66*64) return -2;
ba1a299c 685 // FSK demodulator
a1d17964 686 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
687 if (size < 65) return -3; //did we get a good demod?
ba1a299c 688 //Index map
689 //0 10 20 30 40 50 60
690 //| | | | | | |
691 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
692 //-----------------------------------------------------------------------------
693 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
694 //
695 //XSF(version)facility:codeone+codetwo
696 //Handle the data
a1d17964 697 size_t startIdx = 0;
698 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
699 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
700 if (errChk == 0) return -4; //preamble not found
eb191de6 701
a1d17964 702 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
703 //confirmed proper separator bits found
704 //return start position
705 return (int) startIdx;
1e090a61 706 }
a1d17964 707 return -5;
415274a7 708}
709
710// by marshmellow
711// find viking preamble 0xF200 in already demoded data
712int VikingDemod_AM(uint8_t *dest, size_t *size) {
415274a7 713 //make sure buffer has data
714 if (*size < 64*2) return -2;
715
716 size_t startIdx = 0;
717 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};
718 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
719 if (errChk == 0) return -4; //preamble not found
3ea7254a 720 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
721 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
722 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
723 if ( checkCalc != 0xA8 ) return -5;
14331320 724 if (*size != 64) return -6;
415274a7 725 //return start position
726 return (int) startIdx;
1e090a61 727}
728
6923d3f1 729// find presco preamble 0x10D in already demoded data
730int PrescoDemod(uint8_t *dest, size_t *size) {
731 //make sure buffer has data
732 if (*size < 64*2) return -2;
733
734 size_t startIdx = 0;
735 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
736 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
737 if (errChk == 0) return -4; //preamble not found
738 //return start position
739 return (int) startIdx;
740}
741
04bb0567 742// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
743// BitStream must contain previously askrawdemod and biphasedemoded data
b2c330b3 744int FDXBdemodBI(uint8_t *dest, size_t *size)
04bb0567 745{
746 //make sure buffer has enough data
747 if (*size < 128) return -1;
748
749 size_t startIdx = 0;
750 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
751
752 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
753 if (errChk == 0) return -2; //preamble not found
754 return (int)startIdx;
755}
756
1e090a61 757// by marshmellow
758// FSK Demod then try to locate an AWID ID
a1d17964 759int AWIDdemodFSK(uint8_t *dest, size_t *size)
1e090a61 760{
a1d17964 761 //make sure buffer has enough data
762 if (*size < 96*50) return -1;
763
764 if (justNoise(dest, *size)) return -2;
1e090a61 765
766 // FSK demodulator
a1d17964 767 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
768 if (*size < 96) return -3; //did we get a good demod?
769
770 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
771 size_t startIdx = 0;
772 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
773 if (errChk == 0) return -4; //preamble not found
774 if (*size != 96) return -5;
775 return (int)startIdx;
1e090a61 776}
777
778// by marshmellow
6fe5c94b 779// FSK Demod then try to locate a Farpointe Data (pyramid) ID
a1d17964 780int PyramiddemodFSK(uint8_t *dest, size_t *size)
1e090a61 781{
f3bf15e4 782 //make sure buffer has data
783 if (*size < 128*50) return -5;
a1d17964 784
f3bf15e4 785 //test samples are not just noise
786 if (justNoise(dest, *size)) return -1;
1e090a61 787
f3bf15e4 788 // FSK demodulator
789 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
790 if (*size < 128) return -2; //did we get a good demod?
a1d17964 791
f3bf15e4 792 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
a1d17964 793 size_t startIdx = 0;
794 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
795 if (errChk == 0) return -4; //preamble not found
796 if (*size != 128) return -3;
797 return (int)startIdx;
1e090a61 798}
799
fef74fdc 800// by marshmellow
801// to detect a wave that has heavily clipped (clean) samples
cc15a118 802uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
6de43508 803{
6fe5c94b 804 bool allArePeaks = true;
6de43508 805 uint16_t cntPeaks=0;
db829602 806 size_t loopEnd = 512+160;
1fbf8956 807 if (loopEnd > size) loopEnd = size;
db829602 808 for (size_t i=160; i<loopEnd; i++){
6de43508 809 if (dest[i]>low && dest[i]<high)
6fe5c94b 810 allArePeaks = false;
6de43508 811 else
812 cntPeaks++;
813 }
6fe5c94b 814 if (!allArePeaks){
815 if (cntPeaks > 300) return true;
6de43508 816 }
6fe5c94b 817 return allArePeaks;
6de43508 818}
2eec55c8 819// by marshmellow
820// to help detect clocks on heavily clipped samples
cc15a118 821// based on count of low to low
822int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
13d77ef9 823{
cc15a118 824 uint8_t fndClk[] = {8,16,32,40,50,64,128};
825 size_t startwave;
db829602 826 size_t i = 100;
cc15a118 827 size_t minClk = 255;
828 // get to first full low to prime loop and skip incomplete first pulse
829 while ((dest[i] < high) && (i < size))
830 ++i;
831 while ((dest[i] > low) && (i < size))
832 ++i;
833
834 // loop through all samples
835 while (i < size) {
836 // measure from low to low
837 while ((dest[i] > low) && (i < size))
838 ++i;
839 startwave= i;
840 while ((dest[i] < high) && (i < size))
841 ++i;
842 while ((dest[i] > low) && (i < size))
843 ++i;
844 //get minimum measured distance
845 if (i-startwave < minClk && i < size)
846 minClk = i - startwave;
13d77ef9 847 }
cc15a118 848 // set clock
709665b5 849 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
cc15a118 850 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
851 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
852 return fndClk[clkCnt];
13d77ef9 853 }
cc15a118 854 return 0;
13d77ef9 855}
856
eb191de6 857// by marshmellow
858// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
859// maybe somehow adjust peak trimming value based on samples to fix?
6de43508 860// return start index of best starting position for that clock and return clock (by reference)
861int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
eb191de6 862{
6e984446 863 size_t i=1;
cc15a118 864 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
865 uint8_t clkEnd = 9;
2eec55c8 866 uint8_t loopCnt = 255; //don't need to loop through entire array...
db829602 867 if (size <= loopCnt+60) return -1; //not enough samples
868 size -= 60; //sometimes there is a strange end wave - filter out this....
6e984446 869 //if we already have a valid clock
870 uint8_t clockFnd=0;
cc15a118 871 for (;i<clkEnd;++i)
872 if (clk[i] == *clock) clockFnd = i;
6e984446 873 //clock found but continue to find best startpos
e0165dcf 874
875 //get high and low peak
876 int peak, low;
2eec55c8 877 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
e0165dcf 878
879 //test for large clean peaks
cc15a118 880 if (!clockFnd){
881 if (DetectCleanAskWave(dest, size, peak, low)==1){
882 int ans = DetectStrongAskClock(dest, size, peak, low);
709665b5 883 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
cc15a118 884 for (i=clkEnd-1; i>0; i--){
885 if (clk[i] == ans) {
886 *clock = ans;
887 //clockFnd = i;
888 return 0; // for strong waves i don't use the 'best start position' yet...
889 //break; //clock found but continue to find best startpos [not yet]
890 }
e0165dcf 891 }
892 }
893 }
2eec55c8 894 uint8_t ii;
895 uint8_t clkCnt, tol = 0;
896 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
897 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
898 size_t errCnt = 0;
899 size_t arrLoc, loopEnd;
6e984446 900
cc15a118 901 if (clockFnd>0) {
902 clkCnt = clockFnd;
903 clkEnd = clockFnd+1;
904 }
905 else clkCnt=1;
906
907 //test each valid clock from smallest to greatest to see which lines up
908 for(; clkCnt < clkEnd; clkCnt++){
fef74fdc 909 if (clk[clkCnt] <= 32){
e0165dcf 910 tol=1;
911 }else{
912 tol=0;
913 }
2767fc02 914 //if no errors allowed - keep start within the first clock
cc15a118 915 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
e0165dcf 916 bestErr[clkCnt]=1000;
6e984446 917 //try lining up the peaks by moving starting point (try first few clocks)
cc15a118 918 for (ii=0; ii < loopCnt; ii++){
2eec55c8 919 if (dest[ii] < peak && dest[ii] > low) continue;
920
921 errCnt=0;
922 // now that we have the first one lined up test rest of wave array
923 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
924 for (i=0; i < loopEnd; ++i){
925 arrLoc = ii + (i * clk[clkCnt]);
926 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
927 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
928 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
929 }else{ //error no peak detected
930 errCnt++;
e0165dcf 931 }
932 }
cc15a118 933 //if we found no errors then we can stop here and a low clock (common clocks)
2eec55c8 934 // this is correct one - return this clock
709665b5 935 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
cc15a118 936 if(errCnt==0 && clkCnt<7) {
937 if (!clockFnd) *clock = clk[clkCnt];
2eec55c8 938 return ii;
939 }
940 //if we found errors see if it is lowest so far and save it as best run
941 if(errCnt<bestErr[clkCnt]){
942 bestErr[clkCnt]=errCnt;
943 bestStart[clkCnt]=ii;
944 }
e0165dcf 945 }
946 }
cc15a118 947 uint8_t iii;
e0165dcf 948 uint8_t best=0;
cc15a118 949 for (iii=1; iii<clkEnd; ++iii){
2eec55c8 950 if (bestErr[iii] < bestErr[best]){
951 if (bestErr[iii] == 0) bestErr[iii]=1;
e0165dcf 952 // current best bit to error ratio vs new bit to error ratio
2eec55c8 953 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
e0165dcf 954 best = iii;
955 }
956 }
709665b5 957 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 958 }
cc15a118 959 if (!clockFnd) *clock = clk[best];
e0165dcf 960 return bestStart[best];
eb191de6 961}
ba1a299c 962
963//by marshmellow
6de43508 964//detect psk clock by reading each phase shift
965// a phase shift is determined by measuring the sample length of each wave
966int DetectPSKClock(uint8_t dest[], size_t size, int clock)
ba1a299c 967{
e0165dcf 968 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
969 uint16_t loopCnt = 4096; //don't need to loop through entire array...
970 if (size == 0) return 0;
db829602 971 if (size<loopCnt) loopCnt = size-20;
e0165dcf 972
973 //if we already have a valid clock quit
974 size_t i=1;
975 for (; i < 8; ++i)
976 if (clk[i] == clock) return clock;
977
978 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
979 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
980 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
981 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
982 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
2eec55c8 983 fc = countFC(dest, size, 0);
984 if (fc!=2 && fc!=4 && fc!=8) return -1;
709665b5 985 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
e0165dcf 986
987 //find first full wave
db829602 988 for (i=160; i<loopCnt; i++){
e0165dcf 989 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
990 if (waveStart == 0) {
991 waveStart = i+1;
db829602 992 //prnt("DEBUG: waveStart: %d",waveStart);
e0165dcf 993 } else {
994 waveEnd = i+1;
db829602 995 //prnt("DEBUG: waveEnd: %d",waveEnd);
e0165dcf 996 waveLenCnt = waveEnd-waveStart;
997 if (waveLenCnt > fc){
998 firstFullWave = waveStart;
999 fullWaveLen=waveLenCnt;
1000 break;
1001 }
1002 waveStart=0;
1003 }
1004 }
1005 }
709665b5 1006 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 1007
1008 //test each valid clock from greatest to smallest to see which lines up
1009 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1010 lastClkBit = firstFullWave; //set end of wave as clock align
1011 waveStart = 0;
1012 errCnt=0;
1013 peakcnt=0;
709665b5 1014 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
e0165dcf 1015
1016 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1017 //top edge of wave = start of new wave
1018 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1019 if (waveStart == 0) {
1020 waveStart = i+1;
1021 waveLenCnt=0;
1022 } else { //waveEnd
1023 waveEnd = i+1;
1024 waveLenCnt = waveEnd-waveStart;
1025 if (waveLenCnt > fc){
1026 //if this wave is a phase shift
709665b5 1027 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 1028 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1029 peakcnt++;
1030 lastClkBit+=clk[clkCnt];
1031 } else if (i<lastClkBit+8){
1032 //noise after a phase shift - ignore
1033 } else { //phase shift before supposed to based on clock
1034 errCnt++;
1035 }
1036 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1037 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1038 }
1039 waveStart=i+1;
1040 }
1041 }
1042 }
1043 if (errCnt == 0){
1044 return clk[clkCnt];
1045 }
1046 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1047 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1048 }
1049 //all tested with errors
1050 //return the highest clk with the most peaks found
1051 uint8_t best=7;
1052 for (i=7; i>=1; i--){
1053 if (peaksdet[i] > peaksdet[best]) {
1054 best = i;
1055 }
709665b5 1056 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
e0165dcf 1057 }
1058 return clk[best];
ba1a299c 1059}
1060
db829602 1061int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1062 //find shortest transition from high to low
1063 size_t i = 0;
1064 size_t transition1 = 0;
1065 int lowestTransition = 255;
6fe5c94b 1066 bool lastWasHigh = false;
1067
1068 //find first valid beginning of a high or low wave
1069 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1070 ++i;
1071 while ((dest[i] < peak && dest[i] > low) && (i < size))
1072 ++i;
1073 lastWasHigh = (dest[i] >= peak);
1074
db829602 1075 if (i==size) return 0;
1076 transition1 = i;
1077
1078 for (;i < size; i++) {
1079 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1080 lastWasHigh = (dest[i] >= peak);
1081 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1082 transition1 = i;
1083 }
1084 }
1085 if (lowestTransition == 255) lowestTransition = 0;
709665b5 1086 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
db829602 1087 return lowestTransition;
1088}
1089
6de43508 1090//by marshmellow
1091//detect nrz clock by reading #peaks vs no peaks(or errors)
1092int DetectNRZClock(uint8_t dest[], size_t size, int clock)
ba1a299c 1093{
2eec55c8 1094 size_t i=0;
1095 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1096 size_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1097 if (size == 0) return 0;
db829602 1098 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1099 //if we already have a valid clock quit
1100 for (; i < 8; ++i)
1101 if (clk[i] == clock) return clock;
1102
1103 //get high and low peak
1104 int peak, low;
2eec55c8 1105 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
e0165dcf 1106
db829602 1107 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
2eec55c8 1108 size_t ii;
e0165dcf 1109 uint8_t clkCnt;
1110 uint8_t tol = 0;
db829602 1111 uint16_t smplCnt = 0;
1112 int16_t peakcnt = 0;
1113 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1114 uint16_t maxPeak = 255;
6fe5c94b 1115 bool firstpeak = false;
e0165dcf 1116 //test for large clipped waves
1117 for (i=0; i<loopCnt; i++){
1118 if (dest[i] >= peak || dest[i] <= low){
db829602 1119 if (!firstpeak) continue;
1120 smplCnt++;
e0165dcf 1121 } else {
6fe5c94b 1122 firstpeak=true;
db829602 1123 if (smplCnt > 6 ){
1124 if (maxPeak > smplCnt){
1125 maxPeak = smplCnt;
1126 //prnt("maxPk: %d",maxPeak);
1127 }
1128 peakcnt++;
1129 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1130 smplCnt=0;
e0165dcf 1131 }
e0165dcf 1132 }
1133 }
6fe5c94b 1134 bool errBitHigh = 0;
1135 bool bitHigh = 0;
1136 uint8_t ignoreCnt = 0;
1137 uint8_t ignoreWindow = 4;
1138 bool lastPeakHigh = 0;
1139 int lastBit = 0;
e0165dcf 1140 peakcnt=0;
1141 //test each valid clock from smallest to greatest to see which lines up
1142 for(clkCnt=0; clkCnt < 8; ++clkCnt){
db829602 1143 //ignore clocks smaller than smallest peak
1144 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
e0165dcf 1145 //try lining up the peaks by moving starting point (try first 256)
db829602 1146 for (ii=20; ii < loopCnt; ++ii){
e0165dcf 1147 if ((dest[ii] >= peak) || (dest[ii] <= low)){
6fe5c94b 1148 peakcnt = 0;
1149 bitHigh = false;
1150 ignoreCnt = 0;
1151 lastBit = ii-clk[clkCnt];
db829602 1152 //loop through to see if this start location works
1153 for (i = ii; i < size-20; ++i) {
6fe5c94b 1154 //if we are at a clock bit
db829602 1155 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1156 //test high/low
1157 if (dest[i] >= peak || dest[i] <= low) {
6fe5c94b 1158 //if same peak don't count it
1159 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1160 peakcnt++;
1161 }
1162 lastPeakHigh = (dest[i] >= peak);
1163 bitHigh = true;
1164 errBitHigh = false;
db829602 1165 ignoreCnt = ignoreWindow;
1166 lastBit += clk[clkCnt];
db829602 1167 } else if (i == lastBit + clk[clkCnt] + tol) {
1168 lastBit += clk[clkCnt];
db829602 1169 }
1170 //else if not a clock bit and no peaks
1171 } else if (dest[i] < peak && dest[i] > low){
db829602 1172 if (ignoreCnt==0){
6fe5c94b 1173 bitHigh=false;
1174 if (errBitHigh==true) peakcnt--;
1175 errBitHigh=false;
db829602 1176 } else {
1177 ignoreCnt--;
1178 }
1179 // else if not a clock bit but we have a peak
6fe5c94b 1180 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
db829602 1181 //error bar found no clock...
6fe5c94b 1182 errBitHigh=true;
e0165dcf 1183 }
1184 }
1185 if(peakcnt>peaksdet[clkCnt]) {
1186 peaksdet[clkCnt]=peakcnt;
1187 }
1188 }
1189 }
1190 }
1191 int iii=7;
2eec55c8 1192 uint8_t best=0;
e0165dcf 1193 for (iii=7; iii > 0; iii--){
6fe5c94b 1194 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1195 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
db829602 1196 best = iii;
1197 }
6fe5c94b 1198 } else if (peaksdet[iii] > peaksdet[best]){
1199 best = iii;
e0165dcf 1200 }
709665b5 1201 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 1202 }
db829602 1203
e0165dcf 1204 return clk[best];
ba1a299c 1205}
1206
04d2721b 1207// by marshmellow
1208// convert psk1 demod to psk2 demod
1209// only transition waves are 1s
1210void psk1TOpsk2(uint8_t *BitStream, size_t size)
1211{
1212 size_t i=1;
1213 uint8_t lastBit=BitStream[0];
1214 for (; i<size; i++){
2767fc02 1215 if (BitStream[i]==7){
7a8a982b 1216 //ignore errors
1217 } else if (lastBit!=BitStream[i]){
04d2721b 1218 lastBit=BitStream[i];
1219 BitStream[i]=1;
1220 } else {
1221 BitStream[i]=0;
1222 }
1223 }
1224 return;
1225}
ba1a299c 1226
3bc66a96 1227// by marshmellow
1228// convert psk2 demod to psk1 demod
1229// from only transition waves are 1s to phase shifts change bit
1230void psk2TOpsk1(uint8_t *BitStream, size_t size)
1231{
712ebfa6 1232 uint8_t phase=0;
1233 for (size_t i=0; i<size; i++){
1234 if (BitStream[i]==1){
3bc66a96 1235 phase ^=1;
1236 }
1237 BitStream[i]=phase;
1238 }
1239 return;
1240}
1241
04d2721b 1242// redesigned by marshmellow adjusted from existing decode functions
1243// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
ba1a299c 1244int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1245{
1246 //26 bit 40134 format (don't know other formats)
14331320 1247 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};
1248 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};
1249 size_t startidx = 0;
1250 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1251 // if didn't find preamble try again inverting
1252 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1253 *invert ^= 1;
1254 }
1255 if (*size != 64 && *size != 224) return -2;
1256 if (*invert==1)
1257 for (size_t i = startidx; i < *size; i++)
1258 bitStream[i] ^= 1;
ba1a299c 1259
14331320 1260 return (int) startidx;
ba1a299c 1261}
1262
d1869c33 1263// by marshmellow - demodulate NRZ wave - requires a read with strong signal
04d2721b 1264// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
db829602 1265int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
e0165dcf 1266 if (justNoise(dest, *size)) return -1;
1267 *clk = DetectNRZClock(dest, *size, *clk);
1268 if (*clk==0) return -2;
2eec55c8 1269 size_t i, gLen = 4096;
db829602 1270 if (gLen>*size) gLen = *size-20;
e0165dcf 1271 int high, low;
1272 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
db829602 1273
1274 uint8_t bit=0;
1275 //convert wave samples to 1's and 0's
1276 for(i=20; i < *size-20; i++){
1277 if (dest[i] >= high) bit = 1;
1278 if (dest[i] <= low) bit = 0;
1279 dest[i] = bit;
e0165dcf 1280 }
db829602 1281 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1282 size_t lastBit = 0;
1283 size_t numBits = 0;
1284 for(i=21; i < *size-20; i++) {
1285 //if transition detected or large number of same bits - store the passed bits
1286 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1287 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1288 numBits += (i - lastBit + (*clk/4)) / *clk;
1289 lastBit = i-1;
e0165dcf 1290 }
e0165dcf 1291 }
db829602 1292 *size = numBits;
1293 return 0;
ba1a299c 1294}
1295
1e090a61 1296//by marshmellow
03e6bb4a 1297//detects the bit clock for FSK given the high and low Field Clocks
1298uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1e090a61 1299{
e0165dcf 1300 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1301 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1302 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1303 uint8_t rfLensFnd = 0;
2eec55c8 1304 uint8_t lastFCcnt = 0;
1305 uint16_t fcCounter = 0;
e0165dcf 1306 uint16_t rfCounter = 0;
1307 uint8_t firstBitFnd = 0;
1308 size_t i;
1309 if (size == 0) return 0;
1310
6fe5c94b 1311 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
e0165dcf 1312 rfLensFnd=0;
1313 fcCounter=0;
1314 rfCounter=0;
1315 firstBitFnd=0;
1316 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
6fe5c94b 1317 // prime i to first peak / up transition
1318 for (i = 160; i < size-20; i++)
e0165dcf 1319 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1320 break;
1321
6fe5c94b 1322 for (; i < size-20; i++){
2eec55c8 1323 fcCounter++;
1324 rfCounter++;
1325
1326 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1327 continue;
1328 // else new peak
1329 // if we got less than the small fc + tolerance then set it to the small fc
33a1fe96 1330 // if it is inbetween set it to the last counter
1331 if (fcCounter < fcHigh && fcCounter > fcLow)
1332 fcCounter = lastFCcnt;
1333 else if (fcCounter < fcLow+fcTol)
2eec55c8 1334 fcCounter = fcLow;
1335 else //set it to the large fc
1336 fcCounter = fcHigh;
1337
1338 //look for bit clock (rf/xx)
1339 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1340 //not the same size as the last wave - start of new bit sequence
1341 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1342 for (int ii=0; ii<15; ii++){
6fe5c94b 1343 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
2eec55c8 1344 rfCnts[ii]++;
1345 rfCounter = 0;
1346 break;
e0165dcf 1347 }
e0165dcf 1348 }
2eec55c8 1349 if (rfCounter > 0 && rfLensFnd < 15){
1350 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1351 rfCnts[rfLensFnd]++;
1352 rfLens[rfLensFnd++] = rfCounter;
1353 }
1354 } else {
1355 firstBitFnd++;
e0165dcf 1356 }
2eec55c8 1357 rfCounter=0;
1358 lastFCcnt=fcCounter;
e0165dcf 1359 }
2eec55c8 1360 fcCounter=0;
e0165dcf 1361 }
1362 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1363
1364 for (i=0; i<15; i++){
e0165dcf 1365 //get highest 2 RF values (might need to get more values to compare or compare all?)
1366 if (rfCnts[i]>rfCnts[rfHighest]){
1367 rfHighest3=rfHighest2;
1368 rfHighest2=rfHighest;
1369 rfHighest=i;
1370 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1371 rfHighest3=rfHighest2;
1372 rfHighest2=i;
1373 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1374 rfHighest3=i;
1375 }
709665b5 1376 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
e0165dcf 1377 }
1378 // set allowed clock remainder tolerance to be 1 large field clock length+1
1379 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1380 uint8_t tol1 = fcHigh+1;
1381
709665b5 1382 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
e0165dcf 1383
1384 // loop to find the highest clock that has a remainder less than the tolerance
1385 // compare samples counted divided by
6fe5c94b 1386 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
e0165dcf 1387 int ii=7;
6fe5c94b 1388 for (; ii>=2; ii--){
e0165dcf 1389 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1390 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1391 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
709665b5 1392 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
e0165dcf 1393 break;
1394 }
1395 }
1396 }
1397 }
1398
33a1fe96 1399 if (ii<2) return 0; // oops we went too far
e0165dcf 1400
1401 return clk[ii];
03e6bb4a 1402}
1e090a61 1403
03e6bb4a 1404//by marshmellow
1405//countFC is to detect the field clock lengths.
1406//counts and returns the 2 most common wave lengths
6de43508 1407//mainly used for FSK field clock detection
2eec55c8 1408uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
03e6bb4a 1409{
6fe5c94b 1410 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1411 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
e0165dcf 1412 uint8_t fcLensFnd = 0;
2d99d991 1413 uint8_t lastFCcnt = 0;
2eec55c8 1414 uint8_t fcCounter = 0;
e0165dcf 1415 size_t i;
2d99d991 1416 if (size < 180) return 0;
e0165dcf 1417
1418 // prime i to first up transition
6fe5c94b 1419 for (i = 160; i < size-20; i++)
e0165dcf 1420 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1421 break;
1422
6fe5c94b 1423 for (; i < size-20; i++){
e0165dcf 1424 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1425 // new up transition
1426 fcCounter++;
2eec55c8 1427 if (fskAdj){
1428 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1429 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1430 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1431 if ((fcCounter==9) || fcCounter==4) fcCounter++;
e0165dcf 1432 // save last field clock count (fc/xx)
2eec55c8 1433 lastFCcnt = fcCounter;
1434 }
e0165dcf 1435 // find which fcLens to save it to:
6fe5c94b 1436 for (int ii=0; ii<15; ii++){
e0165dcf 1437 if (fcLens[ii]==fcCounter){
1438 fcCnts[ii]++;
1439 fcCounter=0;
1440 break;
1441 }
1442 }
6fe5c94b 1443 if (fcCounter>0 && fcLensFnd<15){
e0165dcf 1444 //add new fc length
1445 fcCnts[fcLensFnd]++;
1446 fcLens[fcLensFnd++]=fcCounter;
1447 }
1448 fcCounter=0;
1449 } else {
1450 // count sample
1451 fcCounter++;
1452 }
1453 }
1454
6fe5c94b 1455 uint8_t best1=14, best2=14, best3=14;
e0165dcf 1456 uint16_t maxCnt1=0;
1457 // go through fclens and find which ones are bigest 2
6fe5c94b 1458 for (i=0; i<15; i++){
e0165dcf 1459 // get the 3 best FC values
1460 if (fcCnts[i]>maxCnt1) {
1461 best3=best2;
1462 best2=best1;
1463 maxCnt1=fcCnts[i];
1464 best1=i;
1465 } else if(fcCnts[i]>fcCnts[best2]){
1466 best3=best2;
1467 best2=i;
1468 } else if(fcCnts[i]>fcCnts[best3]){
1469 best3=i;
1470 }
709665b5 1471 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 1472 }
6fe5c94b 1473 if (fcLens[best1]==0) return 0;
e0165dcf 1474 uint8_t fcH=0, fcL=0;
1475 if (fcLens[best1]>fcLens[best2]){
1476 fcH=fcLens[best1];
1477 fcL=fcLens[best2];
1478 } else{
1479 fcH=fcLens[best2];
1480 fcL=fcLens[best1];
1481 }
709665b5 1482 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1483 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]);
1484 return 0; //lots of waves not psk or fsk
1485 }
e0165dcf 1486 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1487
1488 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
2eec55c8 1489 if (fskAdj) return fcs;
1490 return fcLens[best1];
6de43508 1491}
1492
1493//by marshmellow - demodulate PSK1 wave
1494//uses wave lengths (# Samples)
1495int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1496{
e0165dcf 1497 if (size == 0) return -1;
2eec55c8 1498 uint16_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1499 if (*size<loopCnt) loopCnt = *size;
1500
db829602 1501 size_t numBits=0;
e0165dcf 1502 uint8_t curPhase = *invert;
6980d66b 1503 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
34ff8985 1504 uint16_t fc=0, fullWaveLen=0, tol=1;
1505 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1506 fc = countFC(dest, *size, 1);
1507 uint8_t fc2 = fc >> 8;
1508 if (fc2 == 10) return -1; //fsk found - quit
1509 fc = fc & 0xFF;
e0165dcf 1510 if (fc!=2 && fc!=4 && fc!=8) return -1;
1511 //PrintAndLog("DEBUG: FC: %d",fc);
1512 *clock = DetectPSKClock(dest, *size, *clock);
2eec55c8 1513 if (*clock == 0) return -1;
6980d66b 1514
34ff8985 1515 //find start of modulating data in trace
1516 uint8_t threshold_value = 123; //-5
1517 i = findModStart(dest, *size, threshold_value, fc);
6980d66b 1518
e0165dcf 1519 //find first phase shift
34ff8985 1520 int avgWaveVal=0, lastAvgWaveVal=0;
1521 waveStart = i;
1522 for (; i<loopCnt; i++) {
1523 // find peak
e0165dcf 1524 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1525 waveEnd = i+1;
6980d66b 1526 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
e0165dcf 1527 waveLenCnt = waveEnd-waveStart;
6980d66b 1528 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
e0165dcf 1529 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1530 firstFullWave = waveStart;
1531 fullWaveLen=waveLenCnt;
34ff8985 1532 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1533 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
e0165dcf 1534 break;
1535 }
1536 waveStart = i+1;
1537 avgWaveVal = 0;
1538 }
2eec55c8 1539 avgWaveVal += dest[i+2];
e0165dcf 1540 }
db829602 1541 if (firstFullWave == 0) {
1542 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1543 // so skip a little to ensure we are past any Start Signal
1544 firstFullWave = 160;
1545 memset(dest, curPhase, firstFullWave / *clock);
1546 } else {
1547 memset(dest, curPhase^1, firstFullWave / *clock);
1548 }
1549 //advance bits
1550 numBits += (firstFullWave / *clock);
1551 //set start of wave as clock align
1552 lastClkBit = firstFullWave;
cf194819 1553 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
34ff8985 1554 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
e0165dcf 1555 waveStart = 0;
e0165dcf 1556 dest[numBits++] = curPhase; //set first read bit
2eec55c8 1557 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
e0165dcf 1558 //top edge of wave = start of new wave
1559 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1560 if (waveStart == 0) {
1561 waveStart = i+1;
2eec55c8 1562 waveLenCnt = 0;
e0165dcf 1563 avgWaveVal = dest[i+1];
1564 } else { //waveEnd
1565 waveEnd = i+1;
1566 waveLenCnt = waveEnd-waveStart;
1567 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1568 if (waveLenCnt > fc){
1569 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
2eec55c8 1570 //this wave is a phase shift
e0165dcf 1571 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1572 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
2eec55c8 1573 curPhase ^= 1;
e0165dcf 1574 dest[numBits++] = curPhase;
1575 lastClkBit += *clock;
2eec55c8 1576 } else if (i < lastClkBit+10+fc){
e0165dcf 1577 //noise after a phase shift - ignore
1578 } else { //phase shift before supposed to based on clock
1579 errCnt++;
2767fc02 1580 dest[numBits++] = 7;
e0165dcf 1581 }
1582 } else if (i+1 > lastClkBit + *clock + tol + fc){
1583 lastClkBit += *clock; //no phase shift but clock bit
1584 dest[numBits++] = curPhase;
34ff8985 1585 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1586 errCnt2++;
1587 if(errCnt2 > 101) return errCnt2;
e0165dcf 1588 }
2eec55c8 1589 avgWaveVal = 0;
1590 waveStart = i+1;
e0165dcf 1591 }
1592 }
2eec55c8 1593 avgWaveVal += dest[i+1];
e0165dcf 1594 }
1595 *size = numBits;
1596 return errCnt;
6de43508 1597}
d1869c33 1598
ab812dfa 1599bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1600 size_t ststart = 0, stend = 0;
1601 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1602}
1603
d1869c33 1604//by marshmellow
1605//attempt to identify a Sequence Terminator in ASK modulated raw wave
ab812dfa 1606bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
d1869c33 1607 size_t bufsize = *size;
1608 //need to loop through all samples and identify our clock, look for the ST pattern
1609 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1610 int clk = 0;
1611 int tol = 0;
b96bcc79 1612 int i, j, skip, start, end, low, high, minClk, waveStart;
d1869c33 1613 bool complete = false;
01d0f8ae 1614 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1615 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
d1869c33 1616 size_t testsize = (bufsize < 512) ? bufsize : 512;
b96bcc79 1617 int phaseoff = 0;
d1869c33 1618 high = low = 128;
1619 memset(tmpbuff, 0, sizeof(tmpbuff));
1620
1621 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1622 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1623 return false; //just noise
1624 }
d1869c33 1625 i = 0;
1626 j = 0;
1627 minClk = 255;
1628 // get to first full low to prime loop and skip incomplete first pulse
1629 while ((buffer[i] < high) && (i < bufsize))
1630 ++i;
1631 while ((buffer[i] > low) && (i < bufsize))
1632 ++i;
1633 skip = i;
1634
1635 // populate tmpbuff buffer with pulse lengths
1636 while (i < bufsize) {
1637 // measure from low to low
1638 while ((buffer[i] > low) && (i < bufsize))
1639 ++i;
1640 start= i;
1641 while ((buffer[i] < high) && (i < bufsize))
1642 ++i;
b96bcc79 1643 //first high point for this wave
1644 waveStart = i;
d1869c33 1645 while ((buffer[i] > low) && (i < bufsize))
1646 ++i;
01d0f8ae 1647 if (j >= (bufsize/32)) {
d1869c33 1648 break;
1649 }
b96bcc79 1650 waveLen[j] = i - waveStart; //first high to first low
d1869c33 1651 tmpbuff[j++] = i - start;
1652 if (i-start < minClk && i < bufsize) {
1653 minClk = i - start;
1654 }
1655 }
1656 // set clock - might be able to get this externally and remove this work...
1657 if (!clk) {
1658 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1659 tol = fndClk[clkCnt]/8;
1660 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1661 clk=fndClk[clkCnt];
1662 break;
1663 }
1664 }
1665 // clock not found - ERROR
1666 if (!clk) {
1667 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1668 return false;
1669 }
1670 } else tol = clk/8;
1671
1672 *foundclock = clk;
1673
1674 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1675 start = -1;
1676 for (i = 0; i < j - 4; ++i) {
1677 skip += tmpbuff[i];
b96bcc79 1678 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1679 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
1680 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
1681 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1682 start = i + 3;
1683 break;
1684 }
1685 }
1686 }
1687 }
1688 }
1689 // first ST not found - ERROR
1690 if (start < 0) {
1691 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1692 return false;
01d0f8ae 1693 } else {
1694 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
d1869c33 1695 }
b96bcc79 1696 if (waveLen[i+2] > clk*1+tol)
1697 phaseoff = 0;
1698 else
1699 phaseoff = clk/2;
1700
d1869c33 1701 // skip over the remainder of ST
1702 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1703
1704 // now do it again to find the end
1705 end = skip;
1706 for (i += 3; i < j - 4; ++i) {
1707 end += tmpbuff[i];
01d0f8ae 1708 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
b96bcc79 1709 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
1710 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
1711 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1712 complete = true;
1713 break;
1714 }
1715 }
1716 }
1717 }
1718 }
b96bcc79 1719 end -= phaseoff;
d1869c33 1720 //didn't find second ST - ERROR
1721 if (!complete) {
1722 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1723 return false;
1724 }
b96bcc79 1725 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);
d1869c33 1726 //now begin to trim out ST so we can use normal demod cmds
1727 start = skip;
1728 size_t datalen = end - start;
1729 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
01d0f8ae 1730 if ( clk - (datalen % clk) <= clk/8) {
1731 // padd the amount off - could be problematic... but shouldn't happen often
1732 datalen += clk - (datalen % clk);
1733 } else if ( (datalen % clk) <= clk/8 ) {
1734 // padd the amount off - could be problematic... but shouldn't happen often
1735 datalen -= datalen % clk;
1736 } else {
d1869c33 1737 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1738 return false;
d1869c33 1739 }
1740 // if datalen is less than one t55xx block - ERROR
1741 if (datalen/clk < 8*4) {
1742 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1743 return false;
1744 }
1745 size_t dataloc = start;
01d0f8ae 1746 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1747 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1748 for ( i=0; i <= (clk/8); ++i ) {
1749 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1750 dataloc -= i;
1751 break;
1752 }
1753 }
1754 }
1755
d1869c33 1756 size_t newloc = 0;
1757 i=0;
01d0f8ae 1758 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
ab812dfa 1759 bool firstrun = true;
d1869c33 1760 // warning - overwriting buffer given with raw wave data with ST removed...
1761 while ( dataloc < bufsize-(clk/2) ) {
cf194819 1762 //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)
d1869c33 1763 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1764 for(i=0; i < clk/2-tol; ++i) {
1765 buffer[dataloc+i] = high+5;
1766 }
dda5a928 1767 } //test for single sample outlier (high between two lows) in the case of very strong waves
1768 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1769 buffer[dataloc] = buffer[dataloc+2];
1770 buffer[dataloc+1] = buffer[dataloc+2];
d1869c33 1771 }
ab812dfa 1772 if (firstrun) {
f75b313b 1773 *stend = dataloc;
1774 *ststart = dataloc-(clk*4);
ab812dfa 1775 firstrun=false;
1776 }
d1869c33 1777 for (i=0; i<datalen; ++i) {
1778 if (i+newloc < bufsize) {
1779 if (i+newloc < dataloc)
1780 buffer[i+newloc] = buffer[dataloc];
1781
01d0f8ae 1782 dataloc++;
d1869c33 1783 }
1784 }
1785 newloc += i;
cf194819 1786 //skip next ST - we just assume it will be there from now on...
01d0f8ae 1787 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
d1869c33 1788 dataloc += clk*4;
1789 }
1790 *size = newloc;
1791 return true;
1792}
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