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[proxmark3-svn] / common / lfdemod.c
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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>
12#include <string.h>
eb191de6 13#include "lfdemod.h"
6426f6ba 14#include "common.h"
15
a126332a 16//un_comment to allow debug print calls when used not on device
6426f6ba 17void dummy(char *fmt, ...){}
18
19#ifndef ON_DEVICE
20#include "ui.h"
a126332a 21#include "cmdparser.h"
22#include "cmddata.h"
6426f6ba 23#define prnt PrintAndLog
24#else
a126332a 25 uint8_t g_debugMode=0;
6426f6ba 26#define prnt dummy
27#endif
6426f6ba 28
a1d17964 29uint8_t justNoise(uint8_t *BitStream, size_t size)
30{
31 static const uint8_t THRESHOLD = 123;
32 //test samples are not just noise
33 uint8_t justNoise1 = 1;
34 for(size_t idx=0; idx < size && justNoise1 ;idx++){
35 justNoise1 = BitStream[idx] < THRESHOLD;
36 }
37 return justNoise1;
38}
39
1e090a61 40//by marshmellow
872e3d4d 41//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 42int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
43{
44 *high=0;
45 *low=255;
46 // get high and low thresholds
2eec55c8 47 for (size_t i=0; i < size; i++){
1e090a61 48 if (BitStream[i] > *high) *high = BitStream[i];
49 if (BitStream[i] < *low) *low = BitStream[i];
50 }
51 if (*high < 123) return -1; // just noise
75cbbe9a 52 *high = ((*high-128)*fuzzHi + 12800)/100;
53 *low = ((*low-128)*fuzzLo + 12800)/100;
1e090a61 54 return 1;
55}
56
a1d17964 57// by marshmellow
58// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
59// returns 1 if passed
60uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
61{
62 uint8_t ans = 0;
63 for (uint8_t i = 0; i < bitLen; i++){
64 ans ^= ((bits >> i) & 1);
65 }
f3bf15e4 66 //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
a1d17964 67 return (ans == pType);
68}
69
a126332a 70//by marshmellow
71// takes a array of binary values, start position, length of bits per parity (includes parity bit),
72// Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run)
73size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
74{
75 uint32_t parityWd = 0;
76 size_t j = 0, bitCnt = 0;
77 for (int word = 0; word < (bLen); word+=pLen){
78 for (int bit=0; bit < pLen; bit++){
79 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
80 BitStream[j++] = (BitStream[startIdx+word+bit]);
81 }
82 j--; // overwrite parity with next data
83 // if parity fails then return 0
84 if (pType == 2) { // then marker bit which should be a 1
85 if (!BitStream[j]) return 0;
86 } else {
87 if (parityTest(parityWd, pLen, pType) == 0) return 0;
88 }
89 bitCnt+=(pLen-1);
90 parityWd = 0;
91 }
92 // if we got here then all the parities passed
93 //return ID start index and size
94 return bitCnt;
95}
96
97// by marshmellow
98// takes a array of binary values, length of bits per parity (includes parity bit),
99// Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run)
100size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
101{
102 uint32_t parityWd = 0;
103 size_t j = 0, bitCnt = 0;
104 for (int word = 0; word < sourceLen; word+=pLen-1) {
105 for (int bit=0; bit < pLen-1; bit++){
106 parityWd = (parityWd << 1) | BitSource[word+bit];
107 dest[j++] = (BitSource[word+bit]);
108 }
109 // if parity fails then return 0
110 if (pType == 2) { // then marker bit which should be a 1
111 dest[j++]=1;
112 } else {
113 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
114 }
115 bitCnt += pLen;
116 parityWd = 0;
117 }
118 // if we got here then all the parities passed
119 //return ID start index and size
120 return bitCnt;
121}
122
123uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
124{
125 uint32_t num = 0;
126 for(int i = 0 ; i < numbits ; i++)
127 {
128 num = (num << 1) | (*src);
129 src++;
130 }
131 return num;
132}
133
134//least significant bit first
135uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
136{
137 uint32_t num = 0;
6b6815bc 138 for(int i = 0 ; i < numbits ; i++) {
a126332a 139 num = (num << 1) | *(src + (numbits-(i+1)));
140 }
141 return num;
142}
143
a1d17964 144//by marshmellow
2147c307 145//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
a1d17964 146uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
147{
e0165dcf 148 uint8_t foundCnt=0;
149 for (int idx=0; idx < *size - pLen; idx++){
150 if (memcmp(BitStream+idx, preamble, pLen) == 0){
151 //first index found
152 foundCnt++;
153 if (foundCnt == 1){
154 *startIdx = idx;
155 }
156 if (foundCnt == 2){
157 *size = idx - *startIdx;
158 return 1;
159 }
160 }
161 }
162 return 0;
a1d17964 163}
164
2147c307 165//by marshmellow
166//takes 1s and 0s and searches for EM410x format - output EM ID
167uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
168{
e0165dcf 169 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
170 // otherwise could be a void with no arguments
171 //set defaults
172 uint32_t i = 0;
2767fc02 173 if (BitStream[1]>1) return 0; //allow only 1s and 0s
174
e0165dcf 175 // 111111111 bit pattern represent start of frame
176 // include 0 in front to help get start pos
177 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
178 uint32_t idx = 0;
179 uint32_t parityBits = 0;
180 uint8_t errChk = 0;
181 uint8_t FmtLen = 10;
182 *startIdx = 0;
183 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
184 if (errChk == 0 || *size < 64) return 0;
185 if (*size > 64) FmtLen = 22;
186 *startIdx += 1; //get rid of 0 from preamble
187 idx = *startIdx + 9;
188 for (i=0; i<FmtLen; i++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
189 parityBits = bytebits_to_byte(BitStream+(i*5)+idx,5);
2eec55c8 190 //check even parity - quit if failed
191 if (parityTest(parityBits, 5, 0) == 0) return 0;
e0165dcf 192 //set uint64 with ID from BitStream
193 for (uint8_t ii=0; ii<4; ii++){
194 *hi = (*hi << 1) | (*lo >> 63);
195 *lo = (*lo << 1) | (BitStream[(i*5)+ii+idx]);
196 }
197 }
198 if (errChk != 0) return 1;
199 //skip last 5 bit parity test for simplicity.
200 // *size = 64 | 128;
201 return 0;
2147c307 202}
203
fef74fdc 204//by marshmellow
205//demodulates strong heavily clipped samples
23f0a7d8 206int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low)
207{
208 size_t bitCnt=0, smplCnt=0, errCnt=0;
209 uint8_t waveHigh = 0;
23f0a7d8 210 for (size_t i=0; i < *size; i++){
211 if (BinStream[i] >= high && waveHigh){
212 smplCnt++;
213 } else if (BinStream[i] <= low && !waveHigh){
214 smplCnt++;
215 } else { //transition
216 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
217 if (smplCnt > clk-(clk/4)-1) { //full clock
218 if (smplCnt > clk + (clk/4)+1) { //too many samples
219 errCnt++;
2767fc02 220 BinStream[bitCnt++]=7;
23f0a7d8 221 } else if (waveHigh) {
222 BinStream[bitCnt++] = invert;
223 BinStream[bitCnt++] = invert;
224 } else if (!waveHigh) {
225 BinStream[bitCnt++] = invert ^ 1;
226 BinStream[bitCnt++] = invert ^ 1;
227 }
228 waveHigh ^= 1;
229 smplCnt = 0;
230 } else if (smplCnt > (clk/2) - (clk/4)-1) {
231 if (waveHigh) {
232 BinStream[bitCnt++] = invert;
233 } else if (!waveHigh) {
234 BinStream[bitCnt++] = invert ^ 1;
235 }
236 waveHigh ^= 1;
237 smplCnt = 0;
238 } else if (!bitCnt) {
239 //first bit
240 waveHigh = (BinStream[i] >= high);
241 smplCnt = 1;
242 } else {
243 smplCnt++;
244 //transition bit oops
245 }
246 } else { //haven't hit new high or new low yet
247 smplCnt++;
248 }
249 }
250 }
251 *size = bitCnt;
252 return errCnt;
253}
254
eb191de6 255//by marshmellow
fef74fdc 256void askAmp(uint8_t *BitStream, size_t size)
257{
258 for(size_t i = 1; i<size; i++){
259 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
260 BitStream[i]=127;
261 else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
262 BitStream[i]=-127;
263 }
264 return;
265}
266
267//by marshmellow
268//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
269int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
eb191de6 270{
fef74fdc 271 if (*size==0) return -1;
6e984446 272 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
2eec55c8 273 if (*clk==0 || start < 0) return -3;
fef74fdc 274 if (*invert != 1) *invert = 0;
275 if (amp==1) askAmp(BinStream, *size);
a126332a 276 if (g_debugMode==2) prnt("DEBUG: clk %d, beststart %d", *clk, start);
fef74fdc 277
2eec55c8 278 uint8_t initLoopMax = 255;
279 if (initLoopMax > *size) initLoopMax = *size;
ba1a299c 280 // Detect high and lows
fef74fdc 281 //25% clip in case highs and lows aren't clipped [marshmellow]
2eec55c8 282 int high, low;
fef74fdc 283 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
284 return -2; //just noise
ba1a299c 285
fef74fdc 286 size_t errCnt = 0;
23f0a7d8 287 // if clean clipped waves detected run alternate demod
288 if (DetectCleanAskWave(BinStream, *size, high, low)) {
a126332a 289 if (g_debugMode==2) prnt("DEBUG: Clean Wave Detected");
fef74fdc 290 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
291 if (askType) //askman
292 return manrawdecode(BinStream, size, 0);
293 else //askraw
294 return errCnt;
23f0a7d8 295 }
296
fef74fdc 297 int lastBit; //set first clock check - can go negative
298 size_t i, bitnum = 0; //output counter
299 uint8_t midBit = 0;
2eec55c8 300 uint8_t tol = 0; //clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
fef74fdc 301 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
bf32dd92 302 size_t MaxBits = 3072;
6e984446 303 lastBit = start - *clk;
fef74fdc 304
6e984446 305 for (i = start; i < *size; ++i) {
fef74fdc 306 if (i-lastBit >= *clk-tol){
307 if (BinStream[i] >= high) {
308 BinStream[bitnum++] = *invert;
309 } else if (BinStream[i] <= low) {
310 BinStream[bitnum++] = *invert ^ 1;
311 } else if (i-lastBit >= *clk+tol) {
312 if (bitnum > 0) {
313 BinStream[bitnum++]=7;
314 errCnt++;
315 }
316 } else { //in tolerance - looking for peak
317 continue;
318 }
319 midBit = 0;
2eec55c8 320 lastBit += *clk;
fef74fdc 321 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
322 if (BinStream[i] >= high) {
323 BinStream[bitnum++] = *invert;
324 } else if (BinStream[i] <= low) {
325 BinStream[bitnum++] = *invert ^ 1;
326 } else if (i-lastBit >= *clk/2+tol) {
327 BinStream[bitnum] = BinStream[bitnum-1];
328 bitnum++;
329 } else { //in tolerance - looking for peak
330 continue;
331 }
332 midBit = 1;
2eec55c8 333 }
334 if (bitnum >= MaxBits) break;
ba1a299c 335 }
2eec55c8 336 *size = bitnum;
6e984446 337 return errCnt;
eb191de6 338}
339
340//by marshmellow
341//take 10 and 01 and manchester decode
342//run through 2 times and take least errCnt
fef74fdc 343int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
eb191de6 344{
13d77ef9 345 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
346 size_t i, ii;
347 uint16_t bestErr = 1000, bestRun = 0;
fef74fdc 348 if (*size < 16) return -1;
2767fc02 349 //find correct start position [alignment]
13d77ef9 350 for (ii=0;ii<2;++ii){
fef74fdc 351 for (i=ii; i<*size-3; i+=2)
2eec55c8 352 if (BitStream[i]==BitStream[i+1])
ba1a299c 353 errCnt++;
2eec55c8 354
ba1a299c 355 if (bestErr>errCnt){
356 bestErr=errCnt;
357 bestRun=ii;
358 }
359 errCnt=0;
360 }
2767fc02 361 //decode
fef74fdc 362 for (i=bestRun; i < *size-3; i+=2){
23f0a7d8 363 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
fef74fdc 364 BitStream[bitnum++]=invert;
23f0a7d8 365 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
fef74fdc 366 BitStream[bitnum++]=invert^1;
23f0a7d8 367 } else {
2767fc02 368 BitStream[bitnum++]=7;
ba1a299c 369 }
23f0a7d8 370 if(bitnum>MaxBits) break;
ba1a299c 371 }
23f0a7d8 372 *size=bitnum;
2eec55c8 373 return bestErr;
f822a063 374}
375
1d0ccbe0 376uint32_t manchesterEncode2Bytes(uint16_t datain) {
377 uint32_t output = 0;
378 uint8_t curBit = 0;
379 for (uint8_t i=0; i<16; i++) {
380 curBit = (datain >> (15-i) & 1);
381 output |= (1<<(((15-i)*2)+curBit));
382 }
383 return output;
384}
385
fef74fdc 386//by marshmellow
387//encode binary data into binary manchester
388int ManchesterEncode(uint8_t *BitStream, size_t size)
389{
390 size_t modIdx=20000, i=0;
391 if (size>modIdx) return -1;
392 for (size_t idx=0; idx < size; idx++){
393 BitStream[idx+modIdx++] = BitStream[idx];
394 BitStream[idx+modIdx++] = BitStream[idx]^1;
395 }
396 for (; i<(size*2); i++){
397 BitStream[i] = BitStream[i+20000];
398 }
399 return i;
400}
401
f822a063 402//by marshmellow
2147c307 403//take 01 or 10 = 1 and 11 or 00 = 0
404//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
13d77ef9 405//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1e090a61 406int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
f822a063 407{
2eec55c8 408 uint16_t bitnum = 0;
409 uint16_t errCnt = 0;
410 size_t i = offset;
2147c307 411 uint16_t MaxBits=512;
412 //if not enough samples - error
413 if (*size < 51) return -1;
414 //check for phase change faults - skip one sample if faulty
415 uint8_t offsetA = 1, offsetB = 1;
416 for (; i<48; i+=2){
417 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
418 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
419 }
420 if (!offsetA && offsetB) offset++;
421 for (i=offset; i<*size-3; i+=2){
422 //check for phase error
13d77ef9 423 if (BitStream[i+1]==BitStream[i+2]) {
2767fc02 424 BitStream[bitnum++]=7;
2147c307 425 errCnt++;
426 }
ba1a299c 427 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1e090a61 428 BitStream[bitnum++]=1^invert;
ba1a299c 429 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1e090a61 430 BitStream[bitnum++]=invert;
ba1a299c 431 } else {
2767fc02 432 BitStream[bitnum++]=7;
ba1a299c 433 errCnt++;
434 }
6de43508 435 if(bitnum>MaxBits) break;
ba1a299c 436 }
437 *size=bitnum;
438 return errCnt;
eb191de6 439}
440
fef74fdc 441// by marshmellow
11081e04 442// demod gProxIIDemod
443// error returns as -x
444// success returns start position in BitStream
445// BitStream must contain previously askrawdemod and biphasedemoded data
446int gProxII_Demod(uint8_t BitStream[], size_t *size)
447{
448 size_t startIdx=0;
449 uint8_t preamble[] = {1,1,1,1,1,0};
450
451 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
452 if (errChk == 0) return -3; //preamble not found
453 if (*size != 96) return -2; //should have found 96 bits
454 //check first 6 spacer bits to verify format
455 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
456 //confirmed proper separator bits found
457 //return start position
458 return (int) startIdx;
459 }
460 return -5;
461}
462
ba1a299c 463//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
f822a063 464size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
eb191de6 465{
2eec55c8 466 size_t last_transition = 0;
467 size_t idx = 1;
ac3ba7ee 468 //uint32_t maxVal=0;
ba1a299c 469 if (fchigh==0) fchigh=10;
470 if (fclow==0) fclow=8;
84871873 471 //set the threshold close to 0 (graph) or 128 std to avoid static
472 uint8_t threshold_value = 123;
ac2df346 473 size_t preLastSample = 0;
474 size_t LastSample = 0;
475 size_t currSample = 0;
ba1a299c 476 // sync to first lo-hi transition, and threshold
477
478 // Need to threshold first sample
6426f6ba 479 // skip 160 samples to allow antenna/samples to settle
480 if(dest[160] < threshold_value) dest[0] = 0;
ba1a299c 481 else dest[0] = 1;
482
483 size_t numBits = 0;
484 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
485 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
486 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
6426f6ba 487 for(idx = 161; idx < size-20; idx++) {
ba1a299c 488 // threshold current value
489
490 if (dest[idx] < threshold_value) dest[idx] = 0;
491 else dest[idx] = 1;
492
493 // Check for 0->1 transition
494 if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
ac2df346 495 preLastSample = LastSample;
496 LastSample = currSample;
497 currSample = idx-last_transition;
6426f6ba 498 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
ba1a299c 499 //do nothing with extra garbage
6426f6ba 500 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves or 3-6 = 5
501 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){
502 dest[numBits-1]=1; //correct previous 9 wave surrounded by 8 waves
ac2df346 503 }
2eec55c8 504 dest[numBits++]=1;
ac2df346 505
6426f6ba 506 } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = garbage
13d77ef9 507 //do nothing with beginning garbage
ac2df346 508 } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's
509 dest[numBits++]=1;
510 } else { //9+ = 10 sample waves
2eec55c8 511 dest[numBits++]=0;
ba1a299c 512 }
513 last_transition = idx;
ba1a299c 514 }
515 }
516 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
eb191de6 517}
518
ba1a299c 519//translate 11111100000 to 10
2eec55c8 520size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
e0165dcf 521 uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 522{
ba1a299c 523 uint8_t lastval=dest[0];
2eec55c8 524 size_t idx=0;
ba1a299c 525 size_t numBits=0;
526 uint32_t n=1;
ba1a299c 527 for( idx=1; idx < size; idx++) {
13d77ef9 528 n++;
2eec55c8 529 if (dest[idx]==lastval) continue;
530
ba1a299c 531 //if lastval was 1, we have a 1->0 crossing
13d77ef9 532 if (dest[idx-1]==1) {
75cbbe9a 533 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 534 } else {// 0->1 crossing
75cbbe9a 535 n = (n * fchigh + rfLen/2) / rfLen;
ba1a299c 536 }
537 if (n == 0) n = 1;
538
2eec55c8 539 memset(dest+numBits, dest[idx-1]^invert , n);
540 numBits += n;
ba1a299c 541 n=0;
542 lastval=dest[idx];
543 }//end for
13d77ef9 544 // if valid extra bits at the end were all the same frequency - add them in
75cbbe9a 545 if (n > rfLen/fchigh) {
13d77ef9 546 if (dest[idx-2]==1) {
75cbbe9a 547 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 548 } else {
75cbbe9a 549 n = (n * fchigh + rfLen/2) / rfLen;
13d77ef9 550 }
2eec55c8 551 memset(dest+numBits, dest[idx-1]^invert , n);
13d77ef9 552 numBits += n;
553 }
ba1a299c 554 return numBits;
eb191de6 555}
6426f6ba 556
eb191de6 557//by marshmellow (from holiman's base)
558// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
f822a063 559int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 560{
ba1a299c 561 // FSK demodulator
562 size = fsk_wave_demod(dest, size, fchigh, fclow);
2eec55c8 563 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
ba1a299c 564 return size;
eb191de6 565}
a1d17964 566
eb191de6 567// loop to get raw HID waveform then FSK demodulate the TAG ID from it
ec75f5c1 568int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
eb191de6 569{
e0165dcf 570 if (justNoise(dest, *size)) return -1;
571
572 size_t numStart=0, size2=*size, startIdx=0;
573 // FSK demodulator
574 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
2eec55c8 575 if (*size < 96*2) return -2;
e0165dcf 576 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
577 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
578 // find bitstring in array
579 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
580 if (errChk == 0) return -3; //preamble not found
581
582 numStart = startIdx + sizeof(preamble);
583 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
584 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
585 if (dest[idx] == dest[idx+1]){
586 return -4; //not manchester data
587 }
588 *hi2 = (*hi2<<1)|(*hi>>31);
589 *hi = (*hi<<1)|(*lo>>31);
590 //Then, shift in a 0 or one into low
591 if (dest[idx] && !dest[idx+1]) // 1 0
592 *lo=(*lo<<1)|1;
593 else // 0 1
594 *lo=(*lo<<1)|0;
595 }
596 return (int)startIdx;
eb191de6 597}
598
ec75f5c1 599// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
a1d17964 600int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
ec75f5c1 601{
a1d17964 602 if (justNoise(dest, *size)) return -1;
603
604 size_t numStart=0, size2=*size, startIdx=0;
ec75f5c1 605 // FSK demodulator
a1d17964 606 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
607 if (*size < 96) return -2;
ec75f5c1 608
a1d17964 609 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
610 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
611
612 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
613 if (errChk == 0) return -3; //preamble not found
614
615 numStart = startIdx + sizeof(preamble);
616 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
617 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
618 if (dest[idx] == dest[idx+1])
619 return -4; //not manchester data
620 *hi2 = (*hi2<<1)|(*hi>>31);
621 *hi = (*hi<<1)|(*lo>>31);
622 //Then, shift in a 0 or one into low
623 if (dest[idx] && !dest[idx+1]) // 1 0
624 *lo=(*lo<<1)|1;
625 else // 0 1
626 *lo=(*lo<<1)|0;
ec75f5c1 627 }
a1d17964 628 return (int)startIdx;
ec75f5c1 629}
630
eb191de6 631int IOdemodFSK(uint8_t *dest, size_t size)
632{
a1d17964 633 if (justNoise(dest, size)) return -1;
ba1a299c 634 //make sure buffer has data
a1d17964 635 if (size < 66*64) return -2;
ba1a299c 636 // FSK demodulator
a1d17964 637 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
638 if (size < 65) return -3; //did we get a good demod?
ba1a299c 639 //Index map
640 //0 10 20 30 40 50 60
641 //| | | | | | |
642 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
643 //-----------------------------------------------------------------------------
644 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
645 //
646 //XSF(version)facility:codeone+codetwo
647 //Handle the data
a1d17964 648 size_t startIdx = 0;
649 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
650 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
651 if (errChk == 0) return -4; //preamble not found
eb191de6 652
a1d17964 653 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
654 //confirmed proper separator bits found
655 //return start position
656 return (int) startIdx;
1e090a61 657 }
a1d17964 658 return -5;
1e090a61 659}
660
70459879 661// by marshmellow
662// find viking preamble 0xF200 in already demoded data
663int VikingDemod_AM(uint8_t *dest, size_t *size) {
70459879 664 //make sure buffer has data
665 if (*size < 64*2) return -2;
666
667 size_t startIdx = 0;
668 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};
669 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
670 if (errChk == 0) return -4; //preamble not found
671 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
672 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
673 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
674 if ( checkCalc != 0xA8 ) return -5;
57c7b44b 675 if (*size != 64) return -6;
70459879 676 //return start position
677 return (int) startIdx;
678}
679
4469412e 680// find presco preamble 0x10D in already demoded data
681int PrescoDemod(uint8_t *dest, size_t *size) {
682 //make sure buffer has data
683 if (*size < 64*2) return -2;
684
685 size_t startIdx = 0;
686 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
687 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
688 if (errChk == 0) return -4; //preamble not found
689 //return start position
690 return (int) startIdx;
691}
692
693
615f21dd 694// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
0df669a2 695// BitStream must contain previously askrawdemod and biphasedemoded data
ad6219fc 696int FDXBdemodBI(uint8_t *dest, size_t *size)
615f21dd 697{
698 //make sure buffer has enough data
0df669a2 699 if (*size < 128) return -1;
615f21dd 700
615f21dd 701 size_t startIdx = 0;
0df669a2 702 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
703
615f21dd 704 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
0df669a2 705 if (errChk == 0) return -2; //preamble not found
615f21dd 706 return (int)startIdx;
707}
1e090a61 708
709// by marshmellow
710// FSK Demod then try to locate an AWID ID
a1d17964 711int AWIDdemodFSK(uint8_t *dest, size_t *size)
1e090a61 712{
a1d17964 713 //make sure buffer has enough data
714 if (*size < 96*50) return -1;
715
716 if (justNoise(dest, *size)) return -2;
1e090a61 717
718 // FSK demodulator
a1d17964 719 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
720 if (*size < 96) return -3; //did we get a good demod?
721
722 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
723 size_t startIdx = 0;
724 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
725 if (errChk == 0) return -4; //preamble not found
726 if (*size != 96) return -5;
727 return (int)startIdx;
1e090a61 728}
729
730// by marshmellow
6426f6ba 731// FSK Demod then try to locate a Farpointe Data (pyramid) ID
a1d17964 732int PyramiddemodFSK(uint8_t *dest, size_t *size)
1e090a61 733{
f3bf15e4 734 //make sure buffer has data
735 if (*size < 128*50) return -5;
a1d17964 736
f3bf15e4 737 //test samples are not just noise
738 if (justNoise(dest, *size)) return -1;
1e090a61 739
f3bf15e4 740 // FSK demodulator
741 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
742 if (*size < 128) return -2; //did we get a good demod?
a1d17964 743
f3bf15e4 744 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
a1d17964 745 size_t startIdx = 0;
746 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
747 if (errChk == 0) return -4; //preamble not found
748 if (*size != 128) return -3;
749 return (int)startIdx;
1e090a61 750}
751
fef74fdc 752// by marshmellow
753// to detect a wave that has heavily clipped (clean) samples
cc15a118 754uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
6de43508 755{
6426f6ba 756 bool allArePeaks = true;
6de43508 757 uint16_t cntPeaks=0;
6426f6ba 758 size_t loopEnd = 512+160;
1fbf8956 759 if (loopEnd > size) loopEnd = size;
6426f6ba 760 for (size_t i=160; i<loopEnd; i++){
6de43508 761 if (dest[i]>low && dest[i]<high)
6426f6ba 762 allArePeaks = false;
6de43508 763 else
764 cntPeaks++;
765 }
6426f6ba 766 if (!allArePeaks){
767 if (cntPeaks > 300) return true;
6de43508 768 }
6426f6ba 769 return allArePeaks;
6de43508 770}
2eec55c8 771// by marshmellow
772// to help detect clocks on heavily clipped samples
cc15a118 773// based on count of low to low
774int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
13d77ef9 775{
cc15a118 776 uint8_t fndClk[] = {8,16,32,40,50,64,128};
777 size_t startwave;
6426f6ba 778 size_t i = 100;
cc15a118 779 size_t minClk = 255;
780 // get to first full low to prime loop and skip incomplete first pulse
781 while ((dest[i] < high) && (i < size))
782 ++i;
783 while ((dest[i] > low) && (i < size))
784 ++i;
785
786 // loop through all samples
787 while (i < size) {
788 // measure from low to low
789 while ((dest[i] > low) && (i < size))
790 ++i;
791 startwave= i;
792 while ((dest[i] < high) && (i < size))
793 ++i;
794 while ((dest[i] > low) && (i < size))
795 ++i;
796 //get minimum measured distance
797 if (i-startwave < minClk && i < size)
798 minClk = i - startwave;
13d77ef9 799 }
cc15a118 800 // set clock
a126332a 801 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
cc15a118 802 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
803 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
804 return fndClk[clkCnt];
13d77ef9 805 }
cc15a118 806 return 0;
13d77ef9 807}
808
eb191de6 809// by marshmellow
810// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
811// maybe somehow adjust peak trimming value based on samples to fix?
6de43508 812// return start index of best starting position for that clock and return clock (by reference)
813int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
eb191de6 814{
6e984446 815 size_t i=1;
cc15a118 816 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
817 uint8_t clkEnd = 9;
2eec55c8 818 uint8_t loopCnt = 255; //don't need to loop through entire array...
6426f6ba 819 if (size <= loopCnt+60) return -1; //not enough samples
820 size -= 60; //sometimes there is a strange end wave - filter out this....
6e984446 821 //if we already have a valid clock
822 uint8_t clockFnd=0;
cc15a118 823 for (;i<clkEnd;++i)
824 if (clk[i] == *clock) clockFnd = i;
6e984446 825 //clock found but continue to find best startpos
e0165dcf 826
827 //get high and low peak
828 int peak, low;
2eec55c8 829 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
e0165dcf 830
831 //test for large clean peaks
cc15a118 832 if (!clockFnd){
833 if (DetectCleanAskWave(dest, size, peak, low)==1){
834 int ans = DetectStrongAskClock(dest, size, peak, low);
a126332a 835 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
cc15a118 836 for (i=clkEnd-1; i>0; i--){
837 if (clk[i] == ans) {
838 *clock = ans;
839 //clockFnd = i;
840 return 0; // for strong waves i don't use the 'best start position' yet...
841 //break; //clock found but continue to find best startpos [not yet]
842 }
e0165dcf 843 }
844 }
845 }
2eec55c8 846 uint8_t ii;
847 uint8_t clkCnt, tol = 0;
848 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
849 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
850 size_t errCnt = 0;
851 size_t arrLoc, loopEnd;
6e984446 852
cc15a118 853 if (clockFnd>0) {
854 clkCnt = clockFnd;
855 clkEnd = clockFnd+1;
856 }
857 else clkCnt=1;
858
859 //test each valid clock from smallest to greatest to see which lines up
860 for(; clkCnt < clkEnd; clkCnt++){
fef74fdc 861 if (clk[clkCnt] <= 32){
e0165dcf 862 tol=1;
863 }else{
864 tol=0;
865 }
2767fc02 866 //if no errors allowed - keep start within the first clock
cc15a118 867 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
e0165dcf 868 bestErr[clkCnt]=1000;
6e984446 869 //try lining up the peaks by moving starting point (try first few clocks)
cc15a118 870 for (ii=0; ii < loopCnt; ii++){
2eec55c8 871 if (dest[ii] < peak && dest[ii] > low) continue;
872
873 errCnt=0;
874 // now that we have the first one lined up test rest of wave array
875 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
876 for (i=0; i < loopEnd; ++i){
877 arrLoc = ii + (i * clk[clkCnt]);
878 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
879 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
880 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
881 }else{ //error no peak detected
882 errCnt++;
e0165dcf 883 }
884 }
cc15a118 885 //if we found no errors then we can stop here and a low clock (common clocks)
2eec55c8 886 // this is correct one - return this clock
a126332a 887 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
cc15a118 888 if(errCnt==0 && clkCnt<7) {
889 if (!clockFnd) *clock = clk[clkCnt];
2eec55c8 890 return ii;
891 }
892 //if we found errors see if it is lowest so far and save it as best run
893 if(errCnt<bestErr[clkCnt]){
894 bestErr[clkCnt]=errCnt;
895 bestStart[clkCnt]=ii;
896 }
e0165dcf 897 }
898 }
cc15a118 899 uint8_t iii;
e0165dcf 900 uint8_t best=0;
cc15a118 901 for (iii=1; iii<clkEnd; ++iii){
2eec55c8 902 if (bestErr[iii] < bestErr[best]){
903 if (bestErr[iii] == 0) bestErr[iii]=1;
e0165dcf 904 // current best bit to error ratio vs new bit to error ratio
2eec55c8 905 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
e0165dcf 906 best = iii;
907 }
908 }
a126332a 909 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 910 }
cc15a118 911 if (!clockFnd) *clock = clk[best];
e0165dcf 912 return bestStart[best];
eb191de6 913}
ba1a299c 914
915//by marshmellow
6de43508 916//detect psk clock by reading each phase shift
917// a phase shift is determined by measuring the sample length of each wave
918int DetectPSKClock(uint8_t dest[], size_t size, int clock)
ba1a299c 919{
e0165dcf 920 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
921 uint16_t loopCnt = 4096; //don't need to loop through entire array...
922 if (size == 0) return 0;
6426f6ba 923 if (size<loopCnt) loopCnt = size-20;
e0165dcf 924
925 //if we already have a valid clock quit
926 size_t i=1;
927 for (; i < 8; ++i)
928 if (clk[i] == clock) return clock;
929
930 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
931 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
932 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
933 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
934 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
2eec55c8 935 fc = countFC(dest, size, 0);
936 if (fc!=2 && fc!=4 && fc!=8) return -1;
a126332a 937 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
e0165dcf 938
939 //find first full wave
6426f6ba 940 for (i=160; i<loopCnt; i++){
e0165dcf 941 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
942 if (waveStart == 0) {
943 waveStart = i+1;
6426f6ba 944 //prnt("DEBUG: waveStart: %d",waveStart);
e0165dcf 945 } else {
946 waveEnd = i+1;
6426f6ba 947 //prnt("DEBUG: waveEnd: %d",waveEnd);
e0165dcf 948 waveLenCnt = waveEnd-waveStart;
949 if (waveLenCnt > fc){
950 firstFullWave = waveStart;
951 fullWaveLen=waveLenCnt;
952 break;
953 }
954 waveStart=0;
955 }
956 }
957 }
a126332a 958 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 959
960 //test each valid clock from greatest to smallest to see which lines up
961 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
962 lastClkBit = firstFullWave; //set end of wave as clock align
963 waveStart = 0;
964 errCnt=0;
965 peakcnt=0;
a126332a 966 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
e0165dcf 967
968 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
969 //top edge of wave = start of new wave
970 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
971 if (waveStart == 0) {
972 waveStart = i+1;
973 waveLenCnt=0;
974 } else { //waveEnd
975 waveEnd = i+1;
976 waveLenCnt = waveEnd-waveStart;
977 if (waveLenCnt > fc){
978 //if this wave is a phase shift
a126332a 979 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 980 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
981 peakcnt++;
982 lastClkBit+=clk[clkCnt];
983 } else if (i<lastClkBit+8){
984 //noise after a phase shift - ignore
985 } else { //phase shift before supposed to based on clock
986 errCnt++;
987 }
988 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
989 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
990 }
991 waveStart=i+1;
992 }
993 }
994 }
995 if (errCnt == 0){
996 return clk[clkCnt];
997 }
998 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
999 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1000 }
1001 //all tested with errors
1002 //return the highest clk with the most peaks found
1003 uint8_t best=7;
1004 for (i=7; i>=1; i--){
1005 if (peaksdet[i] > peaksdet[best]) {
1006 best = i;
1007 }
a126332a 1008 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
e0165dcf 1009 }
1010 return clk[best];
ba1a299c 1011}
1012
6426f6ba 1013int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1014 //find shortest transition from high to low
1015 size_t i = 0;
1016 size_t transition1 = 0;
1017 int lowestTransition = 255;
1018 bool lastWasHigh = false;
1019
1020 //find first valid beginning of a high or low wave
1021 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1022 ++i;
1023 while ((dest[i] < peak && dest[i] > low) && (i < size))
1024 ++i;
1025 lastWasHigh = (dest[i] >= peak);
1026
1027 if (i==size) return 0;
1028 transition1 = i;
1029
1030 for (;i < size; i++) {
1031 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1032 lastWasHigh = (dest[i] >= peak);
1033 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1034 transition1 = i;
1035 }
1036 }
6426f6ba 1037 if (lowestTransition == 255) lowestTransition = 0;
a126332a 1038 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
6426f6ba 1039 return lowestTransition;
1040}
1041
6de43508 1042//by marshmellow
1043//detect nrz clock by reading #peaks vs no peaks(or errors)
1044int DetectNRZClock(uint8_t dest[], size_t size, int clock)
ba1a299c 1045{
2eec55c8 1046 size_t i=0;
1047 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1048 size_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1049 if (size == 0) return 0;
6426f6ba 1050 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1051 //if we already have a valid clock quit
1052 for (; i < 8; ++i)
1053 if (clk[i] == clock) return clock;
1054
1055 //get high and low peak
1056 int peak, low;
2eec55c8 1057 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
e0165dcf 1058
6426f6ba 1059 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
2eec55c8 1060 size_t ii;
e0165dcf 1061 uint8_t clkCnt;
1062 uint8_t tol = 0;
6426f6ba 1063 uint16_t smplCnt = 0;
1064 int16_t peakcnt = 0;
1065 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1066 uint16_t maxPeak = 255;
1067 bool firstpeak = false;
e0165dcf 1068 //test for large clipped waves
1069 for (i=0; i<loopCnt; i++){
1070 if (dest[i] >= peak || dest[i] <= low){
6426f6ba 1071 if (!firstpeak) continue;
1072 smplCnt++;
e0165dcf 1073 } else {
6426f6ba 1074 firstpeak=true;
1075 if (smplCnt > 6 ){
1076 if (maxPeak > smplCnt){
1077 maxPeak = smplCnt;
1078 //prnt("maxPk: %d",maxPeak);
1079 }
1080 peakcnt++;
1081 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1082 smplCnt=0;
e0165dcf 1083 }
e0165dcf 1084 }
1085 }
6426f6ba 1086 bool errBitHigh = 0;
1087 bool bitHigh = 0;
1088 uint8_t ignoreCnt = 0;
1089 uint8_t ignoreWindow = 4;
1090 bool lastPeakHigh = 0;
1091 int lastBit = 0;
e0165dcf 1092 peakcnt=0;
1093 //test each valid clock from smallest to greatest to see which lines up
1094 for(clkCnt=0; clkCnt < 8; ++clkCnt){
6426f6ba 1095 //ignore clocks smaller than smallest peak
1096 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
e0165dcf 1097 //try lining up the peaks by moving starting point (try first 256)
6426f6ba 1098 for (ii=20; ii < loopCnt; ++ii){
e0165dcf 1099 if ((dest[ii] >= peak) || (dest[ii] <= low)){
1100 peakcnt=0;
6426f6ba 1101 bitHigh = false;
1102 ignoreCnt = 0;
1103 lastBit = ii-clk[clkCnt];
1104 //loop through to see if this start location works
1105 for (i = ii; i < size-20; ++i) {
1106 //if we are at a clock bit
1107 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1108 //test high/low
1109 if (dest[i] >= peak || dest[i] <= low) {
1110 //if same peak don't count it
1111 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
e0165dcf 1112 peakcnt++;
6426f6ba 1113 }
1114 lastPeakHigh = (dest[i] >= peak);
1115 bitHigh = true;
1116 errBitHigh = false;
1117 ignoreCnt = ignoreWindow;
1118 lastBit += clk[clkCnt];
1119 } else if (i == lastBit + clk[clkCnt] + tol) {
1120 lastBit += clk[clkCnt];
1121 }
1122 //else if not a clock bit and no peaks
1123 } else if (dest[i] < peak && dest[i] > low){
1124 if (ignoreCnt==0){
1125 bitHigh=false;
1126 if (errBitHigh==true) peakcnt--;
1127 errBitHigh=false;
1128 } else {
1129 ignoreCnt--;
1130 }
1131 // else if not a clock bit but we have a peak
1132 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
1133 //error bar found no clock...
1134 errBitHigh=true;
e0165dcf 1135 }
1136 }
1137 if(peakcnt>peaksdet[clkCnt]) {
1138 peaksdet[clkCnt]=peakcnt;
1139 }
1140 }
1141 }
1142 }
1143 int iii=7;
2eec55c8 1144 uint8_t best=0;
e0165dcf 1145 for (iii=7; iii > 0; iii--){
6426f6ba 1146 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1147 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
1148 best = iii;
1149 }
1150 } else if (peaksdet[iii] > peaksdet[best]){
e0165dcf 1151 best = iii;
1152 }
a126332a 1153 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 1154 }
6426f6ba 1155
e0165dcf 1156 return clk[best];
ba1a299c 1157}
1158
04d2721b 1159// by marshmellow
1160// convert psk1 demod to psk2 demod
1161// only transition waves are 1s
1162void psk1TOpsk2(uint8_t *BitStream, size_t size)
1163{
1164 size_t i=1;
1165 uint8_t lastBit=BitStream[0];
1166 for (; i<size; i++){
2767fc02 1167 if (BitStream[i]==7){
7a8a982b 1168 //ignore errors
1169 } else if (lastBit!=BitStream[i]){
04d2721b 1170 lastBit=BitStream[i];
1171 BitStream[i]=1;
1172 } else {
1173 BitStream[i]=0;
1174 }
1175 }
1176 return;
1177}
ba1a299c 1178
3bc66a96 1179// by marshmellow
1180// convert psk2 demod to psk1 demod
1181// from only transition waves are 1s to phase shifts change bit
1182void psk2TOpsk1(uint8_t *BitStream, size_t size)
1183{
712ebfa6 1184 uint8_t phase=0;
1185 for (size_t i=0; i<size; i++){
1186 if (BitStream[i]==1){
3bc66a96 1187 phase ^=1;
1188 }
1189 BitStream[i]=phase;
1190 }
1191 return;
1192}
1193
04d2721b 1194// redesigned by marshmellow adjusted from existing decode functions
1195// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
ba1a299c 1196int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1197{
1198 //26 bit 40134 format (don't know other formats)
57c7b44b 1199 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};
1200 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};
1201 size_t startidx = 0;
1202 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1203 // if didn't find preamble try again inverting
1204 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1205 *invert ^= 1;
1206 }
1207 if (*size != 64 && *size != 224) return -2;
1208 if (*invert==1)
1209 for (size_t i = startidx; i < *size; i++)
1210 bitStream[i] ^= 1;
ba1a299c 1211
57c7b44b 1212 return (int) startidx;
ba1a299c 1213}
1214
6426f6ba 1215// by marshmellow - demodulate NRZ wave
04d2721b 1216// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
6426f6ba 1217int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
e0165dcf 1218 if (justNoise(dest, *size)) return -1;
1219 *clk = DetectNRZClock(dest, *size, *clk);
1220 if (*clk==0) return -2;
2eec55c8 1221 size_t i, gLen = 4096;
6426f6ba 1222 if (gLen>*size) gLen = *size-20;
e0165dcf 1223 int high, low;
1224 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
6426f6ba 1225
1226 uint8_t bit=0;
1227 //convert wave samples to 1's and 0's
1228 for(i=20; i < *size-20; i++){
1229 if (dest[i] >= high) bit = 1;
1230 if (dest[i] <= low) bit = 0;
1231 dest[i] = bit;
e0165dcf 1232 }
6426f6ba 1233 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1234 size_t lastBit = 0;
1235 size_t numBits = 0;
1236 for(i=21; i < *size-20; i++) {
1237 //if transition detected or large number of same bits - store the passed bits
1238 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1239 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1240 numBits += (i - lastBit + (*clk/4)) / *clk;
1241 lastBit = i-1;
e0165dcf 1242 }
e0165dcf 1243 }
6426f6ba 1244 *size = numBits;
1245 return 0;
ba1a299c 1246}
1247
1e090a61 1248//by marshmellow
03e6bb4a 1249//detects the bit clock for FSK given the high and low Field Clocks
1250uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1e090a61 1251{
e0165dcf 1252 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1253 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1254 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1255 uint8_t rfLensFnd = 0;
2eec55c8 1256 uint8_t lastFCcnt = 0;
1257 uint16_t fcCounter = 0;
e0165dcf 1258 uint16_t rfCounter = 0;
1259 uint8_t firstBitFnd = 0;
1260 size_t i;
1261 if (size == 0) return 0;
1262
6426f6ba 1263 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
e0165dcf 1264 rfLensFnd=0;
1265 fcCounter=0;
1266 rfCounter=0;
1267 firstBitFnd=0;
1268 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
6426f6ba 1269 // prime i to first peak / up transition
1270 for (i = 160; i < size-20; i++)
e0165dcf 1271 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1272 break;
1273
6426f6ba 1274 for (; i < size-20; i++){
2eec55c8 1275 fcCounter++;
1276 rfCounter++;
1277
1278 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1279 continue;
1280 // else new peak
1281 // if we got less than the small fc + tolerance then set it to the small fc
1282 if (fcCounter < fcLow+fcTol)
1283 fcCounter = fcLow;
1284 else //set it to the large fc
1285 fcCounter = fcHigh;
1286
1287 //look for bit clock (rf/xx)
1288 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1289 //not the same size as the last wave - start of new bit sequence
1290 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1291 for (int ii=0; ii<15; ii++){
6426f6ba 1292 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
2eec55c8 1293 rfCnts[ii]++;
1294 rfCounter = 0;
1295 break;
e0165dcf 1296 }
e0165dcf 1297 }
2eec55c8 1298 if (rfCounter > 0 && rfLensFnd < 15){
1299 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1300 rfCnts[rfLensFnd]++;
1301 rfLens[rfLensFnd++] = rfCounter;
1302 }
1303 } else {
1304 firstBitFnd++;
e0165dcf 1305 }
2eec55c8 1306 rfCounter=0;
1307 lastFCcnt=fcCounter;
e0165dcf 1308 }
2eec55c8 1309 fcCounter=0;
e0165dcf 1310 }
1311 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1312
1313 for (i=0; i<15; i++){
e0165dcf 1314 //get highest 2 RF values (might need to get more values to compare or compare all?)
1315 if (rfCnts[i]>rfCnts[rfHighest]){
1316 rfHighest3=rfHighest2;
1317 rfHighest2=rfHighest;
1318 rfHighest=i;
1319 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1320 rfHighest3=rfHighest2;
1321 rfHighest2=i;
1322 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1323 rfHighest3=i;
1324 }
a126332a 1325 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
e0165dcf 1326 }
1327 // set allowed clock remainder tolerance to be 1 large field clock length+1
1328 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1329 uint8_t tol1 = fcHigh+1;
1330
a126332a 1331 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
e0165dcf 1332
1333 // loop to find the highest clock that has a remainder less than the tolerance
1334 // compare samples counted divided by
6426f6ba 1335 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
e0165dcf 1336 int ii=7;
6426f6ba 1337 for (; ii>=2; ii--){
e0165dcf 1338 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1339 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1340 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
a126332a 1341 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
e0165dcf 1342 break;
1343 }
1344 }
1345 }
1346 }
1347
1348 if (ii<0) return 0; // oops we went too far
1349
1350 return clk[ii];
03e6bb4a 1351}
1e090a61 1352
03e6bb4a 1353//by marshmellow
1354//countFC is to detect the field clock lengths.
1355//counts and returns the 2 most common wave lengths
6de43508 1356//mainly used for FSK field clock detection
2eec55c8 1357uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
03e6bb4a 1358{
6426f6ba 1359 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1360 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
e0165dcf 1361 uint8_t fcLensFnd = 0;
1362 uint8_t lastFCcnt=0;
2eec55c8 1363 uint8_t fcCounter = 0;
e0165dcf 1364 size_t i;
1365 if (size == 0) return 0;
1366
1367 // prime i to first up transition
6426f6ba 1368 for (i = 160; i < size-20; i++)
e0165dcf 1369 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1370 break;
1371
6426f6ba 1372 for (; i < size-20; i++){
e0165dcf 1373 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1374 // new up transition
1375 fcCounter++;
2eec55c8 1376 if (fskAdj){
1377 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1378 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1379 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1380 if ((fcCounter==9) || fcCounter==4) fcCounter++;
e0165dcf 1381 // save last field clock count (fc/xx)
2eec55c8 1382 lastFCcnt = fcCounter;
1383 }
e0165dcf 1384 // find which fcLens to save it to:
6426f6ba 1385 for (int ii=0; ii<15; ii++){
e0165dcf 1386 if (fcLens[ii]==fcCounter){
1387 fcCnts[ii]++;
1388 fcCounter=0;
1389 break;
1390 }
1391 }
6426f6ba 1392 if (fcCounter>0 && fcLensFnd<15){
e0165dcf 1393 //add new fc length
1394 fcCnts[fcLensFnd]++;
1395 fcLens[fcLensFnd++]=fcCounter;
1396 }
1397 fcCounter=0;
1398 } else {
1399 // count sample
1400 fcCounter++;
1401 }
1402 }
1403
6426f6ba 1404 uint8_t best1=14, best2=14, best3=14;
e0165dcf 1405 uint16_t maxCnt1=0;
1406 // go through fclens and find which ones are bigest 2
6426f6ba 1407 for (i=0; i<15; i++){
e0165dcf 1408 // get the 3 best FC values
1409 if (fcCnts[i]>maxCnt1) {
1410 best3=best2;
1411 best2=best1;
1412 maxCnt1=fcCnts[i];
1413 best1=i;
1414 } else if(fcCnts[i]>fcCnts[best2]){
1415 best3=best2;
1416 best2=i;
1417 } else if(fcCnts[i]>fcCnts[best3]){
1418 best3=i;
1419 }
a126332a 1420 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 1421 }
6426f6ba 1422 if (fcLens[best1]==0) return 0;
e0165dcf 1423 uint8_t fcH=0, fcL=0;
1424 if (fcLens[best1]>fcLens[best2]){
1425 fcH=fcLens[best1];
1426 fcL=fcLens[best2];
1427 } else{
1428 fcH=fcLens[best2];
1429 fcL=fcLens[best1];
1430 }
a126332a 1431 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1432 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]);
1433 return 0; //lots of waves not psk or fsk
1434 }
e0165dcf 1435 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1436
1437 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
2eec55c8 1438 if (fskAdj) return fcs;
1439 return fcLens[best1];
6de43508 1440}
1441
1442//by marshmellow - demodulate PSK1 wave
1443//uses wave lengths (# Samples)
1444int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1445{
e0165dcf 1446 if (size == 0) return -1;
2eec55c8 1447 uint16_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1448 if (*size<loopCnt) loopCnt = *size;
1449
6426f6ba 1450 size_t numBits=0;
e0165dcf 1451 uint8_t curPhase = *invert;
1452 size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1453 uint8_t fc=0, fullWaveLen=0, tol=1;
1454 uint16_t errCnt=0, waveLenCnt=0;
2eec55c8 1455 fc = countFC(dest, *size, 0);
e0165dcf 1456 if (fc!=2 && fc!=4 && fc!=8) return -1;
1457 //PrintAndLog("DEBUG: FC: %d",fc);
1458 *clock = DetectPSKClock(dest, *size, *clock);
2eec55c8 1459 if (*clock == 0) return -1;
e0165dcf 1460 int avgWaveVal=0, lastAvgWaveVal=0;
1461 //find first phase shift
1462 for (i=0; i<loopCnt; i++){
1463 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1464 waveEnd = i+1;
1465 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1466 waveLenCnt = waveEnd-waveStart;
6426f6ba 1467 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack
e0165dcf 1468 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1469 firstFullWave = waveStart;
1470 fullWaveLen=waveLenCnt;
1471 //if average wave value is > graph 0 then it is an up wave or a 1
2eec55c8 1472 if (lastAvgWaveVal > 123) curPhase ^= 1; //fudge graph 0 a little 123 vs 128
e0165dcf 1473 break;
1474 }
1475 waveStart = i+1;
1476 avgWaveVal = 0;
1477 }
2eec55c8 1478 avgWaveVal += dest[i+2];
e0165dcf 1479 }
6426f6ba 1480 if (firstFullWave == 0) {
1481 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1482 // so skip a little to ensure we are past any Start Signal
1483 firstFullWave = 160;
1484 memset(dest, curPhase, firstFullWave / *clock);
1485 } else {
1486 memset(dest, curPhase^1, firstFullWave / *clock);
1487 }
1488 //advance bits
1489 numBits += (firstFullWave / *clock);
1490 //set start of wave as clock align
1491 lastClkBit = firstFullWave;
e0165dcf 1492 //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 1493 //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
1494 waveStart = 0;
e0165dcf 1495 dest[numBits++] = curPhase; //set first read bit
2eec55c8 1496 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
e0165dcf 1497 //top edge of wave = start of new wave
1498 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1499 if (waveStart == 0) {
1500 waveStart = i+1;
2eec55c8 1501 waveLenCnt = 0;
e0165dcf 1502 avgWaveVal = dest[i+1];
1503 } else { //waveEnd
1504 waveEnd = i+1;
1505 waveLenCnt = waveEnd-waveStart;
1506 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1507 if (waveLenCnt > fc){
1508 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
2eec55c8 1509 //this wave is a phase shift
e0165dcf 1510 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1511 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
2eec55c8 1512 curPhase ^= 1;
e0165dcf 1513 dest[numBits++] = curPhase;
1514 lastClkBit += *clock;
2eec55c8 1515 } else if (i < lastClkBit+10+fc){
e0165dcf 1516 //noise after a phase shift - ignore
1517 } else { //phase shift before supposed to based on clock
1518 errCnt++;
2767fc02 1519 dest[numBits++] = 7;
e0165dcf 1520 }
1521 } else if (i+1 > lastClkBit + *clock + tol + fc){
1522 lastClkBit += *clock; //no phase shift but clock bit
1523 dest[numBits++] = curPhase;
1524 }
2eec55c8 1525 avgWaveVal = 0;
1526 waveStart = i+1;
e0165dcf 1527 }
1528 }
2eec55c8 1529 avgWaveVal += dest[i+1];
e0165dcf 1530 }
1531 *size = numBits;
1532 return errCnt;
6de43508 1533}
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