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shorten em4x05 capture samples
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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 }
e39a92bb 81 if (word+pLen >= bLen) break;
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{
59f726c9 153 // Sanity check. If preamble length is bigger than bitstream length.
154 if ( *size <= pLen ) return 0;
155
e0165dcf 156 uint8_t foundCnt=0;
157 for (int idx=0; idx < *size - pLen; idx++){
158 if (memcmp(BitStream+idx, preamble, pLen) == 0){
159 //first index found
160 foundCnt++;
161 if (foundCnt == 1){
162 *startIdx = idx;
163 }
164 if (foundCnt == 2){
165 *size = idx - *startIdx;
166 return 1;
167 }
168 }
169 }
170 return 0;
a1d17964 171}
172
4c6ccc2b 173// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found)
174// does not look for a repeating preamble
175// em4x05/4x69 only sends preamble once, so look for it once in the first pLen bits
176// leave it generic so it could be reused later...
177bool onePreambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t size, size_t *startIdx) {
178 // Sanity check. If preamble length is bigger than bitstream length.
179 if ( size <= pLen ) return false;
180 for (size_t idx = 0; idx < size - pLen; idx++) {
181 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
182 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
183 *startIdx = idx;
184 return true;
185 }
186 }
187 return false;
188}
189
2147c307 190//by marshmellow
191//takes 1s and 0s and searches for EM410x format - output EM ID
192uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
193{
e0165dcf 194 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
195 // otherwise could be a void with no arguments
196 //set defaults
197 uint32_t i = 0;
2767fc02 198 if (BitStream[1]>1) return 0; //allow only 1s and 0s
199
e0165dcf 200 // 111111111 bit pattern represent start of frame
201 // include 0 in front to help get start pos
202 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
203 uint32_t idx = 0;
204 uint32_t parityBits = 0;
205 uint8_t errChk = 0;
206 uint8_t FmtLen = 10;
207 *startIdx = 0;
208 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
209 if (errChk == 0 || *size < 64) return 0;
210 if (*size > 64) FmtLen = 22;
211 *startIdx += 1; //get rid of 0 from preamble
212 idx = *startIdx + 9;
213 for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
214 parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
2eec55c8 215 //check even parity - quit if failed
216 if (parityTest(parityBits, 5, 0) == 0) return 0;
e0165dcf 217 //set uint64 with ID from BitStream
218 for (uint8_t ii=0; ii<4; ii++){
219 *hi = (*hi << 1) | (*lo >> 63);
220 *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
221 }
222 }
223 if (errChk != 0) return 1;
224 //skip last 5 bit parity test for simplicity.
225 // *size = 64 | 128;
226 return 0;
2147c307 227}
228
fef74fdc 229//by marshmellow
230//demodulates strong heavily clipped samples
23f0a7d8 231int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
232{
233 size_t bitCnt=0, smplCnt=0, errCnt=0;
234 uint8_t waveHigh = 0;
23f0a7d8 235 for (size_t i=0; i < *size; i++){
236 if (BinStream[i] >= high && waveHigh){
237 smplCnt++;
238 } else if (BinStream[i] <= low && !waveHigh){
239 smplCnt++;
240 } else { //transition
241 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
242 if (smplCnt > clk-(clk/4)-1) { //full clock
243 if (smplCnt > clk + (clk/4)+1) { //too many samples
244 errCnt++;
d1869c33 245 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
2767fc02 246 BinStream[bitCnt++]=7;
23f0a7d8 247 } else if (waveHigh) {
248 BinStream[bitCnt++] = invert;
249 BinStream[bitCnt++] = invert;
250 } else if (!waveHigh) {
251 BinStream[bitCnt++] = invert ^ 1;
252 BinStream[bitCnt++] = invert ^ 1;
253 }
254 waveHigh ^= 1;
255 smplCnt = 0;
256 } else if (smplCnt > (clk/2) - (clk/4)-1) {
257 if (waveHigh) {
258 BinStream[bitCnt++] = invert;
259 } else if (!waveHigh) {
260 BinStream[bitCnt++] = invert ^ 1;
261 }
262 waveHigh ^= 1;
263 smplCnt = 0;
264 } else if (!bitCnt) {
265 //first bit
266 waveHigh = (BinStream[i] >= high);
267 smplCnt = 1;
268 } else {
269 smplCnt++;
270 //transition bit oops
271 }
272 } else { //haven't hit new high or new low yet
273 smplCnt++;
274 }
275 }
276 }
277 *size = bitCnt;
278 return errCnt;
279}
280
eb191de6 281//by marshmellow
fef74fdc 282void askAmp(uint8_t *BitStream, size_t size)
283{
16ea2b8c 284 uint8_t Last = 128;
fef74fdc 285 for(size_t i = 1; i<size; i++){
286 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
16ea2b8c 287 Last = 255;
288 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
289 Last = 0;
290
291 BitStream[i-1] = Last;
fef74fdc 292 }
293 return;
294}
01d0f8ae 295
fef74fdc 296//by marshmellow
297//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
298int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
eb191de6 299{
fef74fdc 300 if (*size==0) return -1;
6e984446 301 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
2eec55c8 302 if (*clk==0 || start < 0) return -3;
fef74fdc 303 if (*invert != 1) *invert = 0;
304 if (amp==1) askAmp(BinStream, *size);
01d0f8ae 305 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
fef74fdc 306
2eec55c8 307 uint8_t initLoopMax = 255;
308 if (initLoopMax > *size) initLoopMax = *size;
ba1a299c 309 // Detect high and lows
fef74fdc 310 //25% clip in case highs and lows aren't clipped [marshmellow]
2eec55c8 311 int high, low;
fef74fdc 312 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
313 return -2; //just noise
ba1a299c 314
fef74fdc 315 size_t errCnt = 0;
23f0a7d8 316 // if clean clipped waves detected run alternate demod
317 if (DetectCleanAskWave(BinStream, *size, high, low)) {
d1869c33 318 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
fef74fdc 319 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
320 if (askType) //askman
321 return manrawdecode(BinStream, size, 0);
322 else //askraw
323 return errCnt;
23f0a7d8 324 }
d1869c33 325 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
23f0a7d8 326
d1869c33 327 int lastBit; //set first clock check - can go negative
fef74fdc 328 size_t i, bitnum = 0; //output counter
329 uint8_t midBit = 0;
2eec55c8 330 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 331 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
332 size_t MaxBits = 3072; //max bits to collect
6e984446 333 lastBit = start - *clk;
fef74fdc 334
6e984446 335 for (i = start; i < *size; ++i) {
fef74fdc 336 if (i-lastBit >= *clk-tol){
337 if (BinStream[i] >= high) {
338 BinStream[bitnum++] = *invert;
339 } else if (BinStream[i] <= low) {
340 BinStream[bitnum++] = *invert ^ 1;
341 } else if (i-lastBit >= *clk+tol) {
342 if (bitnum > 0) {
d1869c33 343 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
fef74fdc 344 BinStream[bitnum++]=7;
345 errCnt++;
346 }
347 } else { //in tolerance - looking for peak
348 continue;
349 }
350 midBit = 0;
2eec55c8 351 lastBit += *clk;
fef74fdc 352 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
353 if (BinStream[i] >= high) {
354 BinStream[bitnum++] = *invert;
355 } else if (BinStream[i] <= low) {
356 BinStream[bitnum++] = *invert ^ 1;
357 } else if (i-lastBit >= *clk/2+tol) {
358 BinStream[bitnum] = BinStream[bitnum-1];
359 bitnum++;
360 } else { //in tolerance - looking for peak
361 continue;
362 }
363 midBit = 1;
2eec55c8 364 }
365 if (bitnum >= MaxBits) break;
ba1a299c 366 }
2eec55c8 367 *size = bitnum;
6e984446 368 return errCnt;
eb191de6 369}
370
371//by marshmellow
372//take 10 and 01 and manchester decode
373//run through 2 times and take least errCnt
fef74fdc 374int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
eb191de6 375{
13d77ef9 376 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
377 size_t i, ii;
378 uint16_t bestErr = 1000, bestRun = 0;
fef74fdc 379 if (*size < 16) return -1;
2767fc02 380 //find correct start position [alignment]
13d77ef9 381 for (ii=0;ii<2;++ii){
fef74fdc 382 for (i=ii; i<*size-3; i+=2)
2eec55c8 383 if (BitStream[i]==BitStream[i+1])
ba1a299c 384 errCnt++;
2eec55c8 385
ba1a299c 386 if (bestErr>errCnt){
387 bestErr=errCnt;
388 bestRun=ii;
389 }
390 errCnt=0;
391 }
2767fc02 392 //decode
fef74fdc 393 for (i=bestRun; i < *size-3; i+=2){
23f0a7d8 394 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
fef74fdc 395 BitStream[bitnum++]=invert;
23f0a7d8 396 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
fef74fdc 397 BitStream[bitnum++]=invert^1;
23f0a7d8 398 } else {
2767fc02 399 BitStream[bitnum++]=7;
ba1a299c 400 }
23f0a7d8 401 if(bitnum>MaxBits) break;
ba1a299c 402 }
23f0a7d8 403 *size=bitnum;
2eec55c8 404 return bestErr;
f822a063 405}
406
3606ac0a 407uint32_t manchesterEncode2Bytes(uint16_t datain) {
408 uint32_t output = 0;
409 uint8_t curBit = 0;
410 for (uint8_t i=0; i<16; i++) {
411 curBit = (datain >> (15-i) & 1);
412 output |= (1<<(((15-i)*2)+curBit));
413 }
414 return output;
415}
416
fef74fdc 417//by marshmellow
418//encode binary data into binary manchester
419int ManchesterEncode(uint8_t *BitStream, size_t size)
420{
421 size_t modIdx=20000, i=0;
422 if (size>modIdx) return -1;
423 for (size_t idx=0; idx < size; idx++){
424 BitStream[idx+modIdx++] = BitStream[idx];
425 BitStream[idx+modIdx++] = BitStream[idx]^1;
426 }
427 for (; i<(size*2); i++){
428 BitStream[i] = BitStream[i+20000];
429 }
430 return i;
431}
432
f822a063 433//by marshmellow
2147c307 434//take 01 or 10 = 1 and 11 or 00 = 0
435//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
13d77ef9 436//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1e090a61 437int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
f822a063 438{
2eec55c8 439 uint16_t bitnum = 0;
440 uint16_t errCnt = 0;
441 size_t i = offset;
2147c307 442 uint16_t MaxBits=512;
443 //if not enough samples - error
444 if (*size < 51) return -1;
445 //check for phase change faults - skip one sample if faulty
446 uint8_t offsetA = 1, offsetB = 1;
447 for (; i<48; i+=2){
448 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
449 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
450 }
451 if (!offsetA && offsetB) offset++;
452 for (i=offset; i<*size-3; i+=2){
453 //check for phase error
13d77ef9 454 if (BitStream[i+1]==BitStream[i+2]) {
2767fc02 455 BitStream[bitnum++]=7;
2147c307 456 errCnt++;
457 }
ba1a299c 458 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1e090a61 459 BitStream[bitnum++]=1^invert;
ba1a299c 460 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1e090a61 461 BitStream[bitnum++]=invert;
ba1a299c 462 } else {
2767fc02 463 BitStream[bitnum++]=7;
ba1a299c 464 errCnt++;
465 }
6de43508 466 if(bitnum>MaxBits) break;
ba1a299c 467 }
468 *size=bitnum;
469 return errCnt;
eb191de6 470}
471
fef74fdc 472// by marshmellow
11081e04 473// demod gProxIIDemod
474// error returns as -x
475// success returns start position in BitStream
476// BitStream must contain previously askrawdemod and biphasedemoded data
477int gProxII_Demod(uint8_t BitStream[], size_t *size)
478{
479 size_t startIdx=0;
480 uint8_t preamble[] = {1,1,1,1,1,0};
481
482 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
483 if (errChk == 0) return -3; //preamble not found
484 if (*size != 96) return -2; //should have found 96 bits
485 //check first 6 spacer bits to verify format
486 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
487 //confirmed proper separator bits found
488 //return start position
489 return (int) startIdx;
490 }
cf194819 491 return -5; //spacer bits not found - not a valid gproxII
11081e04 492}
493
cf194819 494//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
f822a063 495size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
eb191de6 496{
2eec55c8 497 size_t last_transition = 0;
498 size_t idx = 1;
ac3ba7ee 499 //uint32_t maxVal=0;
ba1a299c 500 if (fchigh==0) fchigh=10;
501 if (fclow==0) fclow=8;
84871873 502 //set the threshold close to 0 (graph) or 128 std to avoid static
503 uint8_t threshold_value = 123;
f4eadf8a 504 size_t preLastSample = 0;
505 size_t LastSample = 0;
506 size_t currSample = 0;
c85858f5 507 if ( size < 1024 ) return 0; // not enough samples
508
509 // jump to modulating data by finding the first 4 threshold crossings (or first 2 waves)
510 // in case you have junk or noise at the beginning of the trace...
511 uint8_t thresholdCnt = 0;
512 size_t waveSizeCnt = 0;
6980d66b 513 bool isAboveThreshold = dest[idx++] >= threshold_value;
c85858f5 514 for (; idx < size-20; idx++ ) {
515 if(dest[idx] < threshold_value && isAboveThreshold) {
516 thresholdCnt++;
6980d66b 517 if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break;
c85858f5 518 isAboveThreshold = false;
519 waveSizeCnt = 0;
520 } else if (dest[idx] >= threshold_value && !isAboveThreshold) {
521 thresholdCnt++;
6980d66b 522 if (thresholdCnt > 2 && waveSizeCnt < fchigh+1) break;
c85858f5 523 isAboveThreshold = true;
524 waveSizeCnt = 0;
525 } else {
526 waveSizeCnt++;
527 }
528 if (thresholdCnt > 10) break;
529 }
530 if (g_debugMode == 2) prnt("threshold Count reached at %u",idx);
ba1a299c 531
532 // Need to threshold first sample
c85858f5 533 if(dest[idx] < threshold_value) dest[0] = 0;
ba1a299c 534 else dest[0] = 1;
c85858f5 535 idx++;
536
ba1a299c 537 size_t numBits = 0;
538 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
63744b56 539 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
ba1a299c 540 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
cf194819 541 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
c85858f5 542 for(; idx < size-20; idx++) {
ba1a299c 543 // threshold current value
544
545 if (dest[idx] < threshold_value) dest[idx] = 0;
546 else dest[idx] = 1;
547
548 // Check for 0->1 transition
cf194819 549 if (dest[idx-1] < dest[idx]) {
f4eadf8a 550 preLastSample = LastSample;
551 LastSample = currSample;
552 currSample = idx-last_transition;
cf194819 553 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
ba1a299c 554 //do nothing with extra garbage
cf194819 555 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
556 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
c85858f5 557 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
cf194819 558 dest[numBits-1]=1;
f4eadf8a 559 }
2eec55c8 560 dest[numBits++]=1;
f4eadf8a 561
c85858f5 562 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
563 //do nothing with beginning garbage and reset.. should be rare..
564 numBits = 0;
cf194819 565 } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
f4eadf8a 566 dest[numBits++]=1;
cf194819 567 } else { //9+ = 10 sample waves (or 6+ = 7)
2eec55c8 568 dest[numBits++]=0;
ba1a299c 569 }
570 last_transition = idx;
ba1a299c 571 }
572 }
573 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
eb191de6 574}
575
ba1a299c 576//translate 11111100000 to 10
cf194819 577//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
2eec55c8 578size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
e0165dcf 579 uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 580{
ba1a299c 581 uint8_t lastval=dest[0];
2eec55c8 582 size_t idx=0;
ba1a299c 583 size_t numBits=0;
584 uint32_t n=1;
ba1a299c 585 for( idx=1; idx < size; idx++) {
13d77ef9 586 n++;
cf194819 587 if (dest[idx]==lastval) continue; //skip until we hit a transition
2eec55c8 588
cf194819 589 //find out how many bits (n) we collected
ba1a299c 590 //if lastval was 1, we have a 1->0 crossing
13d77ef9 591 if (dest[idx-1]==1) {
6fe5c94b 592 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 593 } else {// 0->1 crossing
75cbbe9a 594 n = (n * fchigh + rfLen/2) / rfLen;
ba1a299c 595 }
596 if (n == 0) n = 1;
597
cf194819 598 //add to our destination the bits we collected
2eec55c8 599 memset(dest+numBits, dest[idx-1]^invert , n);
600 numBits += n;
ba1a299c 601 n=0;
602 lastval=dest[idx];
603 }//end for
13d77ef9 604 // if valid extra bits at the end were all the same frequency - add them in
75cbbe9a 605 if (n > rfLen/fchigh) {
13d77ef9 606 if (dest[idx-2]==1) {
75cbbe9a 607 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 608 } else {
75cbbe9a 609 n = (n * fchigh + rfLen/2) / rfLen;
13d77ef9 610 }
2eec55c8 611 memset(dest+numBits, dest[idx-1]^invert , n);
13d77ef9 612 numBits += n;
613 }
ba1a299c 614 return numBits;
eb191de6 615}
6fe5c94b 616
eb191de6 617//by marshmellow (from holiman's base)
618// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
f822a063 619int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 620{
ba1a299c 621 // FSK demodulator
622 size = fsk_wave_demod(dest, size, fchigh, fclow);
2eec55c8 623 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
ba1a299c 624 return size;
eb191de6 625}
a1d17964 626
eb191de6 627// loop to get raw HID waveform then FSK demodulate the TAG ID from it
ec75f5c1 628int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
eb191de6 629{
e0165dcf 630 if (justNoise(dest, *size)) return -1;
631
632 size_t numStart=0, size2=*size, startIdx=0;
633 // FSK demodulator
634 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
2eec55c8 635 if (*size < 96*2) return -2;
e0165dcf 636 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
637 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
638 // find bitstring in array
639 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
640 if (errChk == 0) return -3; //preamble not found
641
642 numStart = startIdx + sizeof(preamble);
643 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
644 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
645 if (dest[idx] == dest[idx+1]){
646 return -4; //not manchester data
647 }
648 *hi2 = (*hi2<<1)|(*hi>>31);
649 *hi = (*hi<<1)|(*lo>>31);
650 //Then, shift in a 0 or one into low
651 if (dest[idx] && !dest[idx+1]) // 1 0
652 *lo=(*lo<<1)|1;
653 else // 0 1
654 *lo=(*lo<<1)|0;
655 }
656 return (int)startIdx;
eb191de6 657}
658
ec75f5c1 659// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
a1d17964 660int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
ec75f5c1 661{
a1d17964 662 if (justNoise(dest, *size)) return -1;
663
664 size_t numStart=0, size2=*size, startIdx=0;
ec75f5c1 665 // FSK demodulator
a1d17964 666 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
667 if (*size < 96) return -2;
ec75f5c1 668
a1d17964 669 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
670 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
671
672 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
673 if (errChk == 0) return -3; //preamble not found
674
675 numStart = startIdx + sizeof(preamble);
676 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
677 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
678 if (dest[idx] == dest[idx+1])
679 return -4; //not manchester data
680 *hi2 = (*hi2<<1)|(*hi>>31);
681 *hi = (*hi<<1)|(*lo>>31);
682 //Then, shift in a 0 or one into low
683 if (dest[idx] && !dest[idx+1]) // 1 0
684 *lo=(*lo<<1)|1;
685 else // 0 1
686 *lo=(*lo<<1)|0;
ec75f5c1 687 }
a1d17964 688 return (int)startIdx;
ec75f5c1 689}
690
eb191de6 691int IOdemodFSK(uint8_t *dest, size_t size)
692{
a1d17964 693 if (justNoise(dest, size)) return -1;
ba1a299c 694 //make sure buffer has data
a1d17964 695 if (size < 66*64) return -2;
ba1a299c 696 // FSK demodulator
a1d17964 697 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
698 if (size < 65) return -3; //did we get a good demod?
ba1a299c 699 //Index map
700 //0 10 20 30 40 50 60
701 //| | | | | | |
702 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
703 //-----------------------------------------------------------------------------
704 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
705 //
706 //XSF(version)facility:codeone+codetwo
707 //Handle the data
a1d17964 708 size_t startIdx = 0;
709 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
710 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
711 if (errChk == 0) return -4; //preamble not found
eb191de6 712
a1d17964 713 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
714 //confirmed proper separator bits found
715 //return start position
716 return (int) startIdx;
1e090a61 717 }
a1d17964 718 return -5;
415274a7 719}
720
721// by marshmellow
722// find viking preamble 0xF200 in already demoded data
723int VikingDemod_AM(uint8_t *dest, size_t *size) {
415274a7 724 //make sure buffer has data
725 if (*size < 64*2) return -2;
726
727 size_t startIdx = 0;
728 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};
729 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
730 if (errChk == 0) return -4; //preamble not found
3ea7254a 731 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
732 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
733 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
734 if ( checkCalc != 0xA8 ) return -5;
14331320 735 if (*size != 64) return -6;
415274a7 736 //return start position
737 return (int) startIdx;
1e090a61 738}
739
6923d3f1 740// find presco preamble 0x10D in already demoded data
741int PrescoDemod(uint8_t *dest, size_t *size) {
742 //make sure buffer has data
743 if (*size < 64*2) return -2;
744
745 size_t startIdx = 0;
746 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
747 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
748 if (errChk == 0) return -4; //preamble not found
749 //return start position
750 return (int) startIdx;
751}
752
04bb0567 753// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
754// BitStream must contain previously askrawdemod and biphasedemoded data
b2c330b3 755int FDXBdemodBI(uint8_t *dest, size_t *size)
04bb0567 756{
757 //make sure buffer has enough data
758 if (*size < 128) return -1;
759
760 size_t startIdx = 0;
761 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
762
763 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
764 if (errChk == 0) return -2; //preamble not found
765 return (int)startIdx;
766}
767
1e090a61 768// by marshmellow
769// FSK Demod then try to locate an AWID ID
a1d17964 770int AWIDdemodFSK(uint8_t *dest, size_t *size)
1e090a61 771{
a1d17964 772 //make sure buffer has enough data
773 if (*size < 96*50) return -1;
774
775 if (justNoise(dest, *size)) return -2;
1e090a61 776
777 // FSK demodulator
a1d17964 778 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
779 if (*size < 96) return -3; //did we get a good demod?
780
781 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
782 size_t startIdx = 0;
783 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
784 if (errChk == 0) return -4; //preamble not found
785 if (*size != 96) return -5;
786 return (int)startIdx;
1e090a61 787}
788
789// by marshmellow
6fe5c94b 790// FSK Demod then try to locate a Farpointe Data (pyramid) ID
a1d17964 791int PyramiddemodFSK(uint8_t *dest, size_t *size)
1e090a61 792{
f3bf15e4 793 //make sure buffer has data
794 if (*size < 128*50) return -5;
a1d17964 795
f3bf15e4 796 //test samples are not just noise
797 if (justNoise(dest, *size)) return -1;
1e090a61 798
f3bf15e4 799 // FSK demodulator
800 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
801 if (*size < 128) return -2; //did we get a good demod?
a1d17964 802
f3bf15e4 803 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
a1d17964 804 size_t startIdx = 0;
805 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
806 if (errChk == 0) return -4; //preamble not found
807 if (*size != 128) return -3;
808 return (int)startIdx;
1e090a61 809}
810
fef74fdc 811// by marshmellow
812// to detect a wave that has heavily clipped (clean) samples
cc15a118 813uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
6de43508 814{
6fe5c94b 815 bool allArePeaks = true;
6de43508 816 uint16_t cntPeaks=0;
db829602 817 size_t loopEnd = 512+160;
1fbf8956 818 if (loopEnd > size) loopEnd = size;
db829602 819 for (size_t i=160; i<loopEnd; i++){
6de43508 820 if (dest[i]>low && dest[i]<high)
6fe5c94b 821 allArePeaks = false;
6de43508 822 else
823 cntPeaks++;
824 }
6fe5c94b 825 if (!allArePeaks){
826 if (cntPeaks > 300) return true;
6de43508 827 }
6fe5c94b 828 return allArePeaks;
6de43508 829}
2eec55c8 830// by marshmellow
831// to help detect clocks on heavily clipped samples
cc15a118 832// based on count of low to low
833int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
13d77ef9 834{
cc15a118 835 uint8_t fndClk[] = {8,16,32,40,50,64,128};
836 size_t startwave;
db829602 837 size_t i = 100;
cc15a118 838 size_t minClk = 255;
839 // get to first full low to prime loop and skip incomplete first pulse
840 while ((dest[i] < high) && (i < size))
841 ++i;
842 while ((dest[i] > low) && (i < size))
843 ++i;
844
845 // loop through all samples
846 while (i < size) {
847 // measure from low to low
848 while ((dest[i] > low) && (i < size))
849 ++i;
850 startwave= i;
851 while ((dest[i] < high) && (i < size))
852 ++i;
853 while ((dest[i] > low) && (i < size))
854 ++i;
855 //get minimum measured distance
856 if (i-startwave < minClk && i < size)
857 minClk = i - startwave;
13d77ef9 858 }
cc15a118 859 // set clock
709665b5 860 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
cc15a118 861 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
862 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
863 return fndClk[clkCnt];
13d77ef9 864 }
cc15a118 865 return 0;
13d77ef9 866}
867
eb191de6 868// by marshmellow
869// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
870// maybe somehow adjust peak trimming value based on samples to fix?
6de43508 871// return start index of best starting position for that clock and return clock (by reference)
872int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
eb191de6 873{
6e984446 874 size_t i=1;
cc15a118 875 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
876 uint8_t clkEnd = 9;
2eec55c8 877 uint8_t loopCnt = 255; //don't need to loop through entire array...
db829602 878 if (size <= loopCnt+60) return -1; //not enough samples
879 size -= 60; //sometimes there is a strange end wave - filter out this....
6e984446 880 //if we already have a valid clock
881 uint8_t clockFnd=0;
cc15a118 882 for (;i<clkEnd;++i)
883 if (clk[i] == *clock) clockFnd = i;
6e984446 884 //clock found but continue to find best startpos
e0165dcf 885
886 //get high and low peak
887 int peak, low;
2eec55c8 888 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
e0165dcf 889
890 //test for large clean peaks
cc15a118 891 if (!clockFnd){
892 if (DetectCleanAskWave(dest, size, peak, low)==1){
893 int ans = DetectStrongAskClock(dest, size, peak, low);
709665b5 894 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
cc15a118 895 for (i=clkEnd-1; i>0; i--){
896 if (clk[i] == ans) {
897 *clock = ans;
898 //clockFnd = i;
899 return 0; // for strong waves i don't use the 'best start position' yet...
900 //break; //clock found but continue to find best startpos [not yet]
901 }
e0165dcf 902 }
903 }
904 }
2eec55c8 905 uint8_t ii;
906 uint8_t clkCnt, tol = 0;
907 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
908 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
909 size_t errCnt = 0;
910 size_t arrLoc, loopEnd;
6e984446 911
cc15a118 912 if (clockFnd>0) {
913 clkCnt = clockFnd;
914 clkEnd = clockFnd+1;
915 }
916 else clkCnt=1;
917
918 //test each valid clock from smallest to greatest to see which lines up
919 for(; clkCnt < clkEnd; clkCnt++){
fef74fdc 920 if (clk[clkCnt] <= 32){
e0165dcf 921 tol=1;
922 }else{
923 tol=0;
924 }
2767fc02 925 //if no errors allowed - keep start within the first clock
cc15a118 926 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
e0165dcf 927 bestErr[clkCnt]=1000;
6e984446 928 //try lining up the peaks by moving starting point (try first few clocks)
cc15a118 929 for (ii=0; ii < loopCnt; ii++){
2eec55c8 930 if (dest[ii] < peak && dest[ii] > low) continue;
931
932 errCnt=0;
933 // now that we have the first one lined up test rest of wave array
934 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
935 for (i=0; i < loopEnd; ++i){
936 arrLoc = ii + (i * clk[clkCnt]);
937 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
938 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
939 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
940 }else{ //error no peak detected
941 errCnt++;
e0165dcf 942 }
943 }
cc15a118 944 //if we found no errors then we can stop here and a low clock (common clocks)
2eec55c8 945 // this is correct one - return this clock
709665b5 946 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
cc15a118 947 if(errCnt==0 && clkCnt<7) {
948 if (!clockFnd) *clock = clk[clkCnt];
2eec55c8 949 return ii;
950 }
951 //if we found errors see if it is lowest so far and save it as best run
952 if(errCnt<bestErr[clkCnt]){
953 bestErr[clkCnt]=errCnt;
954 bestStart[clkCnt]=ii;
955 }
e0165dcf 956 }
957 }
cc15a118 958 uint8_t iii;
e0165dcf 959 uint8_t best=0;
cc15a118 960 for (iii=1; iii<clkEnd; ++iii){
2eec55c8 961 if (bestErr[iii] < bestErr[best]){
962 if (bestErr[iii] == 0) bestErr[iii]=1;
e0165dcf 963 // current best bit to error ratio vs new bit to error ratio
2eec55c8 964 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
e0165dcf 965 best = iii;
966 }
967 }
709665b5 968 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 969 }
cc15a118 970 if (!clockFnd) *clock = clk[best];
e0165dcf 971 return bestStart[best];
eb191de6 972}
ba1a299c 973
974//by marshmellow
6de43508 975//detect psk clock by reading each phase shift
976// a phase shift is determined by measuring the sample length of each wave
977int DetectPSKClock(uint8_t dest[], size_t size, int clock)
ba1a299c 978{
e0165dcf 979 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
980 uint16_t loopCnt = 4096; //don't need to loop through entire array...
981 if (size == 0) return 0;
db829602 982 if (size<loopCnt) loopCnt = size-20;
e0165dcf 983
984 //if we already have a valid clock quit
985 size_t i=1;
986 for (; i < 8; ++i)
987 if (clk[i] == clock) return clock;
988
989 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
990 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
991 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
992 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
993 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
2eec55c8 994 fc = countFC(dest, size, 0);
995 if (fc!=2 && fc!=4 && fc!=8) return -1;
709665b5 996 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
e0165dcf 997
998 //find first full wave
db829602 999 for (i=160; i<loopCnt; i++){
e0165dcf 1000 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1001 if (waveStart == 0) {
1002 waveStart = i+1;
db829602 1003 //prnt("DEBUG: waveStart: %d",waveStart);
e0165dcf 1004 } else {
1005 waveEnd = i+1;
db829602 1006 //prnt("DEBUG: waveEnd: %d",waveEnd);
e0165dcf 1007 waveLenCnt = waveEnd-waveStart;
1008 if (waveLenCnt > fc){
1009 firstFullWave = waveStart;
1010 fullWaveLen=waveLenCnt;
1011 break;
1012 }
1013 waveStart=0;
1014 }
1015 }
1016 }
709665b5 1017 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 1018
1019 //test each valid clock from greatest to smallest to see which lines up
1020 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1021 lastClkBit = firstFullWave; //set end of wave as clock align
1022 waveStart = 0;
1023 errCnt=0;
1024 peakcnt=0;
709665b5 1025 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
e0165dcf 1026
1027 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1028 //top edge of wave = start of new wave
1029 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1030 if (waveStart == 0) {
1031 waveStart = i+1;
1032 waveLenCnt=0;
1033 } else { //waveEnd
1034 waveEnd = i+1;
1035 waveLenCnt = waveEnd-waveStart;
1036 if (waveLenCnt > fc){
1037 //if this wave is a phase shift
709665b5 1038 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 1039 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1040 peakcnt++;
1041 lastClkBit+=clk[clkCnt];
1042 } else if (i<lastClkBit+8){
1043 //noise after a phase shift - ignore
1044 } else { //phase shift before supposed to based on clock
1045 errCnt++;
1046 }
1047 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1048 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1049 }
1050 waveStart=i+1;
1051 }
1052 }
1053 }
1054 if (errCnt == 0){
1055 return clk[clkCnt];
1056 }
1057 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1058 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1059 }
1060 //all tested with errors
1061 //return the highest clk with the most peaks found
1062 uint8_t best=7;
1063 for (i=7; i>=1; i--){
1064 if (peaksdet[i] > peaksdet[best]) {
1065 best = i;
1066 }
709665b5 1067 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
e0165dcf 1068 }
1069 return clk[best];
ba1a299c 1070}
1071
db829602 1072int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1073 //find shortest transition from high to low
1074 size_t i = 0;
1075 size_t transition1 = 0;
1076 int lowestTransition = 255;
6fe5c94b 1077 bool lastWasHigh = false;
1078
1079 //find first valid beginning of a high or low wave
1080 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1081 ++i;
1082 while ((dest[i] < peak && dest[i] > low) && (i < size))
1083 ++i;
1084 lastWasHigh = (dest[i] >= peak);
1085
db829602 1086 if (i==size) return 0;
1087 transition1 = i;
1088
1089 for (;i < size; i++) {
1090 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1091 lastWasHigh = (dest[i] >= peak);
1092 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1093 transition1 = i;
1094 }
1095 }
1096 if (lowestTransition == 255) lowestTransition = 0;
709665b5 1097 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
db829602 1098 return lowestTransition;
1099}
1100
6de43508 1101//by marshmellow
1102//detect nrz clock by reading #peaks vs no peaks(or errors)
1103int DetectNRZClock(uint8_t dest[], size_t size, int clock)
ba1a299c 1104{
2eec55c8 1105 size_t i=0;
1106 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1107 size_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1108 if (size == 0) return 0;
db829602 1109 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1110 //if we already have a valid clock quit
1111 for (; i < 8; ++i)
1112 if (clk[i] == clock) return clock;
1113
1114 //get high and low peak
1115 int peak, low;
2eec55c8 1116 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
e0165dcf 1117
db829602 1118 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
2eec55c8 1119 size_t ii;
e0165dcf 1120 uint8_t clkCnt;
1121 uint8_t tol = 0;
db829602 1122 uint16_t smplCnt = 0;
1123 int16_t peakcnt = 0;
1124 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1125 uint16_t maxPeak = 255;
6fe5c94b 1126 bool firstpeak = false;
e0165dcf 1127 //test for large clipped waves
1128 for (i=0; i<loopCnt; i++){
1129 if (dest[i] >= peak || dest[i] <= low){
db829602 1130 if (!firstpeak) continue;
1131 smplCnt++;
e0165dcf 1132 } else {
6fe5c94b 1133 firstpeak=true;
db829602 1134 if (smplCnt > 6 ){
1135 if (maxPeak > smplCnt){
1136 maxPeak = smplCnt;
1137 //prnt("maxPk: %d",maxPeak);
1138 }
1139 peakcnt++;
1140 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1141 smplCnt=0;
e0165dcf 1142 }
e0165dcf 1143 }
1144 }
6fe5c94b 1145 bool errBitHigh = 0;
1146 bool bitHigh = 0;
1147 uint8_t ignoreCnt = 0;
1148 uint8_t ignoreWindow = 4;
1149 bool lastPeakHigh = 0;
1150 int lastBit = 0;
e0165dcf 1151 peakcnt=0;
1152 //test each valid clock from smallest to greatest to see which lines up
1153 for(clkCnt=0; clkCnt < 8; ++clkCnt){
db829602 1154 //ignore clocks smaller than smallest peak
1155 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
e0165dcf 1156 //try lining up the peaks by moving starting point (try first 256)
db829602 1157 for (ii=20; ii < loopCnt; ++ii){
e0165dcf 1158 if ((dest[ii] >= peak) || (dest[ii] <= low)){
6fe5c94b 1159 peakcnt = 0;
1160 bitHigh = false;
1161 ignoreCnt = 0;
1162 lastBit = ii-clk[clkCnt];
db829602 1163 //loop through to see if this start location works
1164 for (i = ii; i < size-20; ++i) {
6fe5c94b 1165 //if we are at a clock bit
db829602 1166 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1167 //test high/low
1168 if (dest[i] >= peak || dest[i] <= low) {
6fe5c94b 1169 //if same peak don't count it
1170 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1171 peakcnt++;
1172 }
1173 lastPeakHigh = (dest[i] >= peak);
1174 bitHigh = true;
1175 errBitHigh = false;
db829602 1176 ignoreCnt = ignoreWindow;
1177 lastBit += clk[clkCnt];
db829602 1178 } else if (i == lastBit + clk[clkCnt] + tol) {
1179 lastBit += clk[clkCnt];
db829602 1180 }
1181 //else if not a clock bit and no peaks
1182 } else if (dest[i] < peak && dest[i] > low){
db829602 1183 if (ignoreCnt==0){
6fe5c94b 1184 bitHigh=false;
1185 if (errBitHigh==true) peakcnt--;
1186 errBitHigh=false;
db829602 1187 } else {
1188 ignoreCnt--;
1189 }
1190 // else if not a clock bit but we have a peak
6fe5c94b 1191 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
db829602 1192 //error bar found no clock...
6fe5c94b 1193 errBitHigh=true;
e0165dcf 1194 }
1195 }
1196 if(peakcnt>peaksdet[clkCnt]) {
1197 peaksdet[clkCnt]=peakcnt;
1198 }
1199 }
1200 }
1201 }
1202 int iii=7;
2eec55c8 1203 uint8_t best=0;
e0165dcf 1204 for (iii=7; iii > 0; iii--){
6fe5c94b 1205 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1206 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
db829602 1207 best = iii;
1208 }
6fe5c94b 1209 } else if (peaksdet[iii] > peaksdet[best]){
1210 best = iii;
e0165dcf 1211 }
709665b5 1212 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 1213 }
db829602 1214
e0165dcf 1215 return clk[best];
ba1a299c 1216}
1217
04d2721b 1218// by marshmellow
1219// convert psk1 demod to psk2 demod
1220// only transition waves are 1s
1221void psk1TOpsk2(uint8_t *BitStream, size_t size)
1222{
1223 size_t i=1;
1224 uint8_t lastBit=BitStream[0];
1225 for (; i<size; i++){
2767fc02 1226 if (BitStream[i]==7){
7a8a982b 1227 //ignore errors
1228 } else if (lastBit!=BitStream[i]){
04d2721b 1229 lastBit=BitStream[i];
1230 BitStream[i]=1;
1231 } else {
1232 BitStream[i]=0;
1233 }
1234 }
1235 return;
1236}
ba1a299c 1237
3bc66a96 1238// by marshmellow
1239// convert psk2 demod to psk1 demod
1240// from only transition waves are 1s to phase shifts change bit
1241void psk2TOpsk1(uint8_t *BitStream, size_t size)
1242{
712ebfa6 1243 uint8_t phase=0;
1244 for (size_t i=0; i<size; i++){
1245 if (BitStream[i]==1){
3bc66a96 1246 phase ^=1;
1247 }
1248 BitStream[i]=phase;
1249 }
1250 return;
1251}
1252
04d2721b 1253// redesigned by marshmellow adjusted from existing decode functions
1254// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
ba1a299c 1255int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1256{
1257 //26 bit 40134 format (don't know other formats)
14331320 1258 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};
1259 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};
1260 size_t startidx = 0;
1261 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1262 // if didn't find preamble try again inverting
1263 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1264 *invert ^= 1;
1265 }
1266 if (*size != 64 && *size != 224) return -2;
1267 if (*invert==1)
1268 for (size_t i = startidx; i < *size; i++)
1269 bitStream[i] ^= 1;
ba1a299c 1270
14331320 1271 return (int) startidx;
ba1a299c 1272}
1273
d1869c33 1274// by marshmellow - demodulate NRZ wave - requires a read with strong signal
04d2721b 1275// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
db829602 1276int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
e0165dcf 1277 if (justNoise(dest, *size)) return -1;
1278 *clk = DetectNRZClock(dest, *size, *clk);
1279 if (*clk==0) return -2;
2eec55c8 1280 size_t i, gLen = 4096;
db829602 1281 if (gLen>*size) gLen = *size-20;
e0165dcf 1282 int high, low;
1283 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
db829602 1284
1285 uint8_t bit=0;
1286 //convert wave samples to 1's and 0's
1287 for(i=20; i < *size-20; i++){
1288 if (dest[i] >= high) bit = 1;
1289 if (dest[i] <= low) bit = 0;
1290 dest[i] = bit;
e0165dcf 1291 }
db829602 1292 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1293 size_t lastBit = 0;
1294 size_t numBits = 0;
1295 for(i=21; i < *size-20; i++) {
1296 //if transition detected or large number of same bits - store the passed bits
1297 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1298 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1299 numBits += (i - lastBit + (*clk/4)) / *clk;
1300 lastBit = i-1;
e0165dcf 1301 }
e0165dcf 1302 }
db829602 1303 *size = numBits;
1304 return 0;
ba1a299c 1305}
1306
1e090a61 1307//by marshmellow
03e6bb4a 1308//detects the bit clock for FSK given the high and low Field Clocks
1309uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1e090a61 1310{
e0165dcf 1311 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1312 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1313 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1314 uint8_t rfLensFnd = 0;
2eec55c8 1315 uint8_t lastFCcnt = 0;
1316 uint16_t fcCounter = 0;
e0165dcf 1317 uint16_t rfCounter = 0;
1318 uint8_t firstBitFnd = 0;
1319 size_t i;
1320 if (size == 0) return 0;
1321
6fe5c94b 1322 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
e0165dcf 1323 rfLensFnd=0;
1324 fcCounter=0;
1325 rfCounter=0;
1326 firstBitFnd=0;
1327 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
6fe5c94b 1328 // prime i to first peak / up transition
1329 for (i = 160; i < size-20; i++)
e0165dcf 1330 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1331 break;
1332
6fe5c94b 1333 for (; i < size-20; i++){
2eec55c8 1334 fcCounter++;
1335 rfCounter++;
1336
1337 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1338 continue;
1339 // else new peak
1340 // if we got less than the small fc + tolerance then set it to the small fc
1341 if (fcCounter < fcLow+fcTol)
1342 fcCounter = fcLow;
1343 else //set it to the large fc
1344 fcCounter = fcHigh;
1345
1346 //look for bit clock (rf/xx)
1347 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1348 //not the same size as the last wave - start of new bit sequence
1349 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1350 for (int ii=0; ii<15; ii++){
6fe5c94b 1351 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
2eec55c8 1352 rfCnts[ii]++;
1353 rfCounter = 0;
1354 break;
e0165dcf 1355 }
e0165dcf 1356 }
2eec55c8 1357 if (rfCounter > 0 && rfLensFnd < 15){
1358 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1359 rfCnts[rfLensFnd]++;
1360 rfLens[rfLensFnd++] = rfCounter;
1361 }
1362 } else {
1363 firstBitFnd++;
e0165dcf 1364 }
2eec55c8 1365 rfCounter=0;
1366 lastFCcnt=fcCounter;
e0165dcf 1367 }
2eec55c8 1368 fcCounter=0;
e0165dcf 1369 }
1370 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1371
1372 for (i=0; i<15; i++){
e0165dcf 1373 //get highest 2 RF values (might need to get more values to compare or compare all?)
1374 if (rfCnts[i]>rfCnts[rfHighest]){
1375 rfHighest3=rfHighest2;
1376 rfHighest2=rfHighest;
1377 rfHighest=i;
1378 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1379 rfHighest3=rfHighest2;
1380 rfHighest2=i;
1381 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1382 rfHighest3=i;
1383 }
709665b5 1384 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
e0165dcf 1385 }
1386 // set allowed clock remainder tolerance to be 1 large field clock length+1
1387 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1388 uint8_t tol1 = fcHigh+1;
1389
709665b5 1390 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
e0165dcf 1391
1392 // loop to find the highest clock that has a remainder less than the tolerance
1393 // compare samples counted divided by
6fe5c94b 1394 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
e0165dcf 1395 int ii=7;
6fe5c94b 1396 for (; ii>=2; ii--){
e0165dcf 1397 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1398 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1399 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
709665b5 1400 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
e0165dcf 1401 break;
1402 }
1403 }
1404 }
1405 }
1406
1407 if (ii<0) return 0; // oops we went too far
1408
1409 return clk[ii];
03e6bb4a 1410}
1e090a61 1411
03e6bb4a 1412//by marshmellow
1413//countFC is to detect the field clock lengths.
1414//counts and returns the 2 most common wave lengths
6de43508 1415//mainly used for FSK field clock detection
2eec55c8 1416uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
03e6bb4a 1417{
6fe5c94b 1418 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1419 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
e0165dcf 1420 uint8_t fcLensFnd = 0;
2d99d991 1421 uint8_t lastFCcnt = 0;
2eec55c8 1422 uint8_t fcCounter = 0;
e0165dcf 1423 size_t i;
2d99d991 1424 if (size < 180) return 0;
e0165dcf 1425
1426 // prime i to first up transition
6fe5c94b 1427 for (i = 160; i < size-20; i++)
e0165dcf 1428 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1429 break;
1430
6fe5c94b 1431 for (; i < size-20; i++){
e0165dcf 1432 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1433 // new up transition
1434 fcCounter++;
2eec55c8 1435 if (fskAdj){
1436 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1437 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1438 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1439 if ((fcCounter==9) || fcCounter==4) fcCounter++;
e0165dcf 1440 // save last field clock count (fc/xx)
2eec55c8 1441 lastFCcnt = fcCounter;
1442 }
e0165dcf 1443 // find which fcLens to save it to:
6fe5c94b 1444 for (int ii=0; ii<15; ii++){
e0165dcf 1445 if (fcLens[ii]==fcCounter){
1446 fcCnts[ii]++;
1447 fcCounter=0;
1448 break;
1449 }
1450 }
6fe5c94b 1451 if (fcCounter>0 && fcLensFnd<15){
e0165dcf 1452 //add new fc length
1453 fcCnts[fcLensFnd]++;
1454 fcLens[fcLensFnd++]=fcCounter;
1455 }
1456 fcCounter=0;
1457 } else {
1458 // count sample
1459 fcCounter++;
1460 }
1461 }
1462
6fe5c94b 1463 uint8_t best1=14, best2=14, best3=14;
e0165dcf 1464 uint16_t maxCnt1=0;
1465 // go through fclens and find which ones are bigest 2
6fe5c94b 1466 for (i=0; i<15; i++){
e0165dcf 1467 // get the 3 best FC values
1468 if (fcCnts[i]>maxCnt1) {
1469 best3=best2;
1470 best2=best1;
1471 maxCnt1=fcCnts[i];
1472 best1=i;
1473 } else if(fcCnts[i]>fcCnts[best2]){
1474 best3=best2;
1475 best2=i;
1476 } else if(fcCnts[i]>fcCnts[best3]){
1477 best3=i;
1478 }
709665b5 1479 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 1480 }
6fe5c94b 1481 if (fcLens[best1]==0) return 0;
e0165dcf 1482 uint8_t fcH=0, fcL=0;
1483 if (fcLens[best1]>fcLens[best2]){
1484 fcH=fcLens[best1];
1485 fcL=fcLens[best2];
1486 } else{
1487 fcH=fcLens[best2];
1488 fcL=fcLens[best1];
1489 }
709665b5 1490 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1491 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]);
1492 return 0; //lots of waves not psk or fsk
1493 }
e0165dcf 1494 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1495
1496 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
2eec55c8 1497 if (fskAdj) return fcs;
1498 return fcLens[best1];
6de43508 1499}
1500
1501//by marshmellow - demodulate PSK1 wave
1502//uses wave lengths (# Samples)
1503int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1504{
e0165dcf 1505 if (size == 0) return -1;
2eec55c8 1506 uint16_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1507 if (*size<loopCnt) loopCnt = *size;
1508
db829602 1509 size_t numBits=0;
e0165dcf 1510 uint8_t curPhase = *invert;
6980d66b 1511 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
e0165dcf 1512 uint8_t fc=0, fullWaveLen=0, tol=1;
1513 uint16_t errCnt=0, waveLenCnt=0;
2eec55c8 1514 fc = countFC(dest, *size, 0);
e0165dcf 1515 if (fc!=2 && fc!=4 && fc!=8) return -1;
1516 //PrintAndLog("DEBUG: FC: %d",fc);
1517 *clock = DetectPSKClock(dest, *size, *clock);
2eec55c8 1518 if (*clock == 0) return -1;
6980d66b 1519 // jump to modulating data by finding the first 2 threshold crossings (or first 1 waves)
1520 // in case you have junk or noise at the beginning of the trace...
1521 uint8_t thresholdCnt = 0;
1522 size_t waveSizeCnt = 0;
1523 uint8_t threshold_value = 123; //-5
1524 bool isAboveThreshold = dest[i++] >= threshold_value;
1525 for (; i < *size-20; i++ ) {
1526 if(dest[i] < threshold_value && isAboveThreshold) {
1527 thresholdCnt++;
1528 if (thresholdCnt > 2 && waveSizeCnt < fc+1) break;
1529 isAboveThreshold = false;
1530 waveSizeCnt = 0;
1531 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
1532 thresholdCnt++;
1533 if (thresholdCnt > 2 && waveSizeCnt < fc+1) break;
1534 isAboveThreshold = true;
1535 waveSizeCnt = 0;
1536 } else {
1537 waveSizeCnt++;
1538 }
1539 if (thresholdCnt > 10) break;
1540 }
1541 if (g_debugMode == 2) prnt("DEBUG PSK: threshold Count reached at %u, count: %u",i, thresholdCnt);
1542
1543
e0165dcf 1544 int avgWaveVal=0, lastAvgWaveVal=0;
6980d66b 1545 waveStart = i+1;
e0165dcf 1546 //find first phase shift
6980d66b 1547 for (; i<loopCnt; i++){
e0165dcf 1548 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1549 waveEnd = i+1;
6980d66b 1550 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
e0165dcf 1551 waveLenCnt = waveEnd-waveStart;
6980d66b 1552 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
e0165dcf 1553 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1554 firstFullWave = waveStart;
1555 fullWaveLen=waveLenCnt;
1556 //if average wave value is > graph 0 then it is an up wave or a 1
6980d66b 1557 if (lastAvgWaveVal > threshold_value) curPhase ^= 1; //fudge graph 0 a little 123 vs 128
e0165dcf 1558 break;
1559 }
1560 waveStart = i+1;
1561 avgWaveVal = 0;
1562 }
2eec55c8 1563 avgWaveVal += dest[i+2];
e0165dcf 1564 }
db829602 1565 if (firstFullWave == 0) {
1566 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1567 // so skip a little to ensure we are past any Start Signal
1568 firstFullWave = 160;
1569 memset(dest, curPhase, firstFullWave / *clock);
1570 } else {
1571 memset(dest, curPhase^1, firstFullWave / *clock);
1572 }
1573 //advance bits
1574 numBits += (firstFullWave / *clock);
1575 //set start of wave as clock align
1576 lastClkBit = firstFullWave;
cf194819 1577 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u",firstFullWave,fullWaveLen);
1578 if (g_debugMode==2) prnt("DEBUG: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
e0165dcf 1579 waveStart = 0;
e0165dcf 1580 dest[numBits++] = curPhase; //set first read bit
2eec55c8 1581 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
e0165dcf 1582 //top edge of wave = start of new wave
1583 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1584 if (waveStart == 0) {
1585 waveStart = i+1;
2eec55c8 1586 waveLenCnt = 0;
e0165dcf 1587 avgWaveVal = dest[i+1];
1588 } else { //waveEnd
1589 waveEnd = i+1;
1590 waveLenCnt = waveEnd-waveStart;
1591 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1592 if (waveLenCnt > fc){
1593 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
2eec55c8 1594 //this wave is a phase shift
e0165dcf 1595 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1596 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
2eec55c8 1597 curPhase ^= 1;
e0165dcf 1598 dest[numBits++] = curPhase;
1599 lastClkBit += *clock;
2eec55c8 1600 } else if (i < lastClkBit+10+fc){
e0165dcf 1601 //noise after a phase shift - ignore
1602 } else { //phase shift before supposed to based on clock
1603 errCnt++;
2767fc02 1604 dest[numBits++] = 7;
e0165dcf 1605 }
1606 } else if (i+1 > lastClkBit + *clock + tol + fc){
1607 lastClkBit += *clock; //no phase shift but clock bit
1608 dest[numBits++] = curPhase;
1609 }
2eec55c8 1610 avgWaveVal = 0;
1611 waveStart = i+1;
e0165dcf 1612 }
1613 }
2eec55c8 1614 avgWaveVal += dest[i+1];
e0165dcf 1615 }
1616 *size = numBits;
1617 return errCnt;
6de43508 1618}
d1869c33 1619
1620//by marshmellow
1621//attempt to identify a Sequence Terminator in ASK modulated raw wave
1622bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1623 size_t bufsize = *size;
1624 //need to loop through all samples and identify our clock, look for the ST pattern
1625 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1626 int clk = 0;
1627 int tol = 0;
b96bcc79 1628 int i, j, skip, start, end, low, high, minClk, waveStart;
d1869c33 1629 bool complete = false;
01d0f8ae 1630 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1631 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
d1869c33 1632 size_t testsize = (bufsize < 512) ? bufsize : 512;
b96bcc79 1633 int phaseoff = 0;
d1869c33 1634 high = low = 128;
1635 memset(tmpbuff, 0, sizeof(tmpbuff));
1636
1637 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1638 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1639 return false; //just noise
1640 }
d1869c33 1641 i = 0;
1642 j = 0;
1643 minClk = 255;
1644 // get to first full low to prime loop and skip incomplete first pulse
1645 while ((buffer[i] < high) && (i < bufsize))
1646 ++i;
1647 while ((buffer[i] > low) && (i < bufsize))
1648 ++i;
1649 skip = i;
1650
1651 // populate tmpbuff buffer with pulse lengths
1652 while (i < bufsize) {
1653 // measure from low to low
1654 while ((buffer[i] > low) && (i < bufsize))
1655 ++i;
1656 start= i;
1657 while ((buffer[i] < high) && (i < bufsize))
1658 ++i;
b96bcc79 1659 //first high point for this wave
1660 waveStart = i;
d1869c33 1661 while ((buffer[i] > low) && (i < bufsize))
1662 ++i;
01d0f8ae 1663 if (j >= (bufsize/32)) {
d1869c33 1664 break;
1665 }
b96bcc79 1666 waveLen[j] = i - waveStart; //first high to first low
d1869c33 1667 tmpbuff[j++] = i - start;
1668 if (i-start < minClk && i < bufsize) {
1669 minClk = i - start;
1670 }
1671 }
1672 // set clock - might be able to get this externally and remove this work...
1673 if (!clk) {
1674 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1675 tol = fndClk[clkCnt]/8;
1676 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1677 clk=fndClk[clkCnt];
1678 break;
1679 }
1680 }
1681 // clock not found - ERROR
1682 if (!clk) {
1683 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1684 return false;
1685 }
1686 } else tol = clk/8;
1687
1688 *foundclock = clk;
1689
1690 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1691 start = -1;
1692 for (i = 0; i < j - 4; ++i) {
1693 skip += tmpbuff[i];
b96bcc79 1694 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1695 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
1696 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
1697 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1698 start = i + 3;
1699 break;
1700 }
1701 }
1702 }
1703 }
1704 }
1705 // first ST not found - ERROR
1706 if (start < 0) {
1707 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1708 return false;
01d0f8ae 1709 } else {
1710 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
d1869c33 1711 }
b96bcc79 1712 if (waveLen[i+2] > clk*1+tol)
1713 phaseoff = 0;
1714 else
1715 phaseoff = clk/2;
1716
d1869c33 1717 // skip over the remainder of ST
1718 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1719
1720 // now do it again to find the end
1721 end = skip;
1722 for (i += 3; i < j - 4; ++i) {
1723 end += tmpbuff[i];
01d0f8ae 1724 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 1725 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
1726 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
1727 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1728 complete = true;
1729 break;
1730 }
1731 }
1732 }
1733 }
1734 }
b96bcc79 1735 end -= phaseoff;
d1869c33 1736 //didn't find second ST - ERROR
1737 if (!complete) {
1738 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1739 return false;
1740 }
b96bcc79 1741 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 1742 //now begin to trim out ST so we can use normal demod cmds
1743 start = skip;
1744 size_t datalen = end - start;
1745 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
01d0f8ae 1746 if ( clk - (datalen % clk) <= clk/8) {
1747 // padd the amount off - could be problematic... but shouldn't happen often
1748 datalen += clk - (datalen % clk);
1749 } else if ( (datalen % clk) <= clk/8 ) {
1750 // padd the amount off - could be problematic... but shouldn't happen often
1751 datalen -= datalen % clk;
1752 } else {
d1869c33 1753 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1754 return false;
d1869c33 1755 }
1756 // if datalen is less than one t55xx block - ERROR
1757 if (datalen/clk < 8*4) {
1758 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1759 return false;
1760 }
1761 size_t dataloc = start;
01d0f8ae 1762 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1763 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1764 for ( i=0; i <= (clk/8); ++i ) {
1765 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1766 dataloc -= i;
1767 break;
1768 }
1769 }
1770 }
1771
d1869c33 1772 size_t newloc = 0;
1773 i=0;
01d0f8ae 1774 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
1775
d1869c33 1776 // warning - overwriting buffer given with raw wave data with ST removed...
1777 while ( dataloc < bufsize-(clk/2) ) {
cf194819 1778 //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 1779 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1780 for(i=0; i < clk/2-tol; ++i) {
1781 buffer[dataloc+i] = high+5;
1782 }
1783 }
1784 for (i=0; i<datalen; ++i) {
1785 if (i+newloc < bufsize) {
1786 if (i+newloc < dataloc)
1787 buffer[i+newloc] = buffer[dataloc];
1788
01d0f8ae 1789 dataloc++;
d1869c33 1790 }
1791 }
1792 newloc += i;
cf194819 1793 //skip next ST - we just assume it will be there from now on...
01d0f8ae 1794 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
d1869c33 1795 dataloc += clk*4;
1796 }
1797 *size = newloc;
1798 return true;
1799}
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