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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 }
f3bf15e4 65 //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
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),
71// Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run)
72size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
73{
74 uint32_t parityWd = 0;
75 size_t j = 0, bitCnt = 0;
76 for (int word = 0; word < (bLen); word+=pLen){
77 for (int bit=0; bit < pLen; bit++){
78 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
79 BitStream[j++] = (BitStream[startIdx+word+bit]);
80 }
81 j--; // overwrite parity with next data
82 // if parity fails then return 0
83 if (pType == 2) { // then marker bit which should be a 1
84 if (!BitStream[j]) return 0;
85 } else {
86 if (parityTest(parityWd, pLen, pType) == 0) return 0;
87 }
88 bitCnt+=(pLen-1);
89 parityWd = 0;
90 }
91 // if we got here then all the parities passed
92 //return ID start index and size
93 return bitCnt;
94}
95
96// by marshmellow
97// takes a array of binary values, length of bits per parity (includes parity bit),
98// Parity Type (1 for odd; 0 for even; 2 Always 1's), and binary Length (length to run)
99size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
100{
101 uint32_t parityWd = 0;
102 size_t j = 0, bitCnt = 0;
103 for (int word = 0; word < sourceLen; word+=pLen-1) {
104 for (int bit=0; bit < pLen-1; bit++){
105 parityWd = (parityWd << 1) | BitSource[word+bit];
106 dest[j++] = (BitSource[word+bit]);
107 }
108 // if parity fails then return 0
109 if (pType == 2) { // then marker bit which should be a 1
110 dest[j++]=1;
111 } else {
112 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
113 }
114 bitCnt += pLen;
115 parityWd = 0;
116 }
117 // if we got here then all the parities passed
118 //return ID start index and size
119 return bitCnt;
120}
121
122uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
123{
124 uint32_t num = 0;
125 for(int i = 0 ; i < numbits ; i++)
126 {
127 num = (num << 1) | (*src);
128 src++;
129 }
130 return num;
131}
132
133//least significant bit first
134uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
135{
136 uint32_t num = 0;
137 for(int i = 0 ; i < numbits ; i++)
138 {
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++;
d1869c33 220 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
2767fc02 221 BinStream[bitCnt++]=7;
23f0a7d8 222 } else if (waveHigh) {
223 BinStream[bitCnt++] = invert;
224 BinStream[bitCnt++] = invert;
225 } else if (!waveHigh) {
226 BinStream[bitCnt++] = invert ^ 1;
227 BinStream[bitCnt++] = invert ^ 1;
228 }
229 waveHigh ^= 1;
230 smplCnt = 0;
231 } else if (smplCnt > (clk/2) - (clk/4)-1) {
232 if (waveHigh) {
233 BinStream[bitCnt++] = invert;
234 } else if (!waveHigh) {
235 BinStream[bitCnt++] = invert ^ 1;
236 }
237 waveHigh ^= 1;
238 smplCnt = 0;
239 } else if (!bitCnt) {
240 //first bit
241 waveHigh = (BinStream[i] >= high);
242 smplCnt = 1;
243 } else {
244 smplCnt++;
245 //transition bit oops
246 }
247 } else { //haven't hit new high or new low yet
248 smplCnt++;
249 }
250 }
251 }
252 *size = bitCnt;
253 return errCnt;
254}
255
eb191de6 256//by marshmellow
fef74fdc 257void askAmp(uint8_t *BitStream, size_t size)
258{
259 for(size_t i = 1; i<size; i++){
260 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
261 BitStream[i]=127;
262 else if(BitStream[i]-BitStream[i-1]<=-20) //large jump down
263 BitStream[i]=-127;
264 }
265 return;
266}
267
268//by marshmellow
269//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
270int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType)
eb191de6 271{
fef74fdc 272 if (*size==0) return -1;
6e984446 273 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
2eec55c8 274 if (*clk==0 || start < 0) return -3;
fef74fdc 275 if (*invert != 1) *invert = 0;
276 if (amp==1) askAmp(BinStream, *size);
d1869c33 277 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d", *clk, start);
fef74fdc 278
2eec55c8 279 uint8_t initLoopMax = 255;
280 if (initLoopMax > *size) initLoopMax = *size;
ba1a299c 281 // Detect high and lows
fef74fdc 282 //25% clip in case highs and lows aren't clipped [marshmellow]
2eec55c8 283 int high, low;
fef74fdc 284 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
285 return -2; //just noise
ba1a299c 286
fef74fdc 287 size_t errCnt = 0;
23f0a7d8 288 // if clean clipped waves detected run alternate demod
289 if (DetectCleanAskWave(BinStream, *size, high, low)) {
d1869c33 290 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
fef74fdc 291 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low);
292 if (askType) //askman
293 return manrawdecode(BinStream, size, 0);
294 else //askraw
295 return errCnt;
23f0a7d8 296 }
d1869c33 297 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
23f0a7d8 298
d1869c33 299 int lastBit; //set first clock check - can go negative
fef74fdc 300 size_t i, bitnum = 0; //output counter
301 uint8_t midBit = 0;
2eec55c8 302 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 303 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
304 size_t MaxBits = 3072; //max bits to collect
6e984446 305 lastBit = start - *clk;
fef74fdc 306
6e984446 307 for (i = start; i < *size; ++i) {
fef74fdc 308 if (i-lastBit >= *clk-tol){
309 if (BinStream[i] >= high) {
310 BinStream[bitnum++] = *invert;
311 } else if (BinStream[i] <= low) {
312 BinStream[bitnum++] = *invert ^ 1;
313 } else if (i-lastBit >= *clk+tol) {
314 if (bitnum > 0) {
d1869c33 315 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
fef74fdc 316 BinStream[bitnum++]=7;
317 errCnt++;
318 }
319 } else { //in tolerance - looking for peak
320 continue;
321 }
322 midBit = 0;
2eec55c8 323 lastBit += *clk;
fef74fdc 324 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
325 if (BinStream[i] >= high) {
326 BinStream[bitnum++] = *invert;
327 } else if (BinStream[i] <= low) {
328 BinStream[bitnum++] = *invert ^ 1;
329 } else if (i-lastBit >= *clk/2+tol) {
330 BinStream[bitnum] = BinStream[bitnum-1];
331 bitnum++;
332 } else { //in tolerance - looking for peak
333 continue;
334 }
335 midBit = 1;
2eec55c8 336 }
337 if (bitnum >= MaxBits) break;
ba1a299c 338 }
2eec55c8 339 *size = bitnum;
6e984446 340 return errCnt;
eb191de6 341}
342
343//by marshmellow
344//take 10 and 01 and manchester decode
345//run through 2 times and take least errCnt
fef74fdc 346int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert)
eb191de6 347{
13d77ef9 348 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
349 size_t i, ii;
350 uint16_t bestErr = 1000, bestRun = 0;
fef74fdc 351 if (*size < 16) return -1;
2767fc02 352 //find correct start position [alignment]
13d77ef9 353 for (ii=0;ii<2;++ii){
fef74fdc 354 for (i=ii; i<*size-3; i+=2)
2eec55c8 355 if (BitStream[i]==BitStream[i+1])
ba1a299c 356 errCnt++;
2eec55c8 357
ba1a299c 358 if (bestErr>errCnt){
359 bestErr=errCnt;
360 bestRun=ii;
361 }
362 errCnt=0;
363 }
2767fc02 364 //decode
fef74fdc 365 for (i=bestRun; i < *size-3; i+=2){
23f0a7d8 366 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
fef74fdc 367 BitStream[bitnum++]=invert;
23f0a7d8 368 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
fef74fdc 369 BitStream[bitnum++]=invert^1;
23f0a7d8 370 } else {
2767fc02 371 BitStream[bitnum++]=7;
ba1a299c 372 }
23f0a7d8 373 if(bitnum>MaxBits) break;
ba1a299c 374 }
23f0a7d8 375 *size=bitnum;
2eec55c8 376 return bestErr;
f822a063 377}
378
3606ac0a 379uint32_t manchesterEncode2Bytes(uint16_t datain) {
380 uint32_t output = 0;
381 uint8_t curBit = 0;
382 for (uint8_t i=0; i<16; i++) {
383 curBit = (datain >> (15-i) & 1);
384 output |= (1<<(((15-i)*2)+curBit));
385 }
386 return output;
387}
388
fef74fdc 389//by marshmellow
390//encode binary data into binary manchester
391int ManchesterEncode(uint8_t *BitStream, size_t size)
392{
393 size_t modIdx=20000, i=0;
394 if (size>modIdx) return -1;
395 for (size_t idx=0; idx < size; idx++){
396 BitStream[idx+modIdx++] = BitStream[idx];
397 BitStream[idx+modIdx++] = BitStream[idx]^1;
398 }
399 for (; i<(size*2); i++){
400 BitStream[i] = BitStream[i+20000];
401 }
402 return i;
403}
404
f822a063 405//by marshmellow
2147c307 406//take 01 or 10 = 1 and 11 or 00 = 0
407//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
13d77ef9 408//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1e090a61 409int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
f822a063 410{
2eec55c8 411 uint16_t bitnum = 0;
412 uint16_t errCnt = 0;
413 size_t i = offset;
2147c307 414 uint16_t MaxBits=512;
415 //if not enough samples - error
416 if (*size < 51) return -1;
417 //check for phase change faults - skip one sample if faulty
418 uint8_t offsetA = 1, offsetB = 1;
419 for (; i<48; i+=2){
420 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
421 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
422 }
423 if (!offsetA && offsetB) offset++;
424 for (i=offset; i<*size-3; i+=2){
425 //check for phase error
13d77ef9 426 if (BitStream[i+1]==BitStream[i+2]) {
2767fc02 427 BitStream[bitnum++]=7;
2147c307 428 errCnt++;
429 }
ba1a299c 430 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1e090a61 431 BitStream[bitnum++]=1^invert;
ba1a299c 432 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1e090a61 433 BitStream[bitnum++]=invert;
ba1a299c 434 } else {
2767fc02 435 BitStream[bitnum++]=7;
ba1a299c 436 errCnt++;
437 }
6de43508 438 if(bitnum>MaxBits) break;
ba1a299c 439 }
440 *size=bitnum;
441 return errCnt;
eb191de6 442}
443
fef74fdc 444// by marshmellow
11081e04 445// demod gProxIIDemod
446// error returns as -x
447// success returns start position in BitStream
448// BitStream must contain previously askrawdemod and biphasedemoded data
449int gProxII_Demod(uint8_t BitStream[], size_t *size)
450{
451 size_t startIdx=0;
452 uint8_t preamble[] = {1,1,1,1,1,0};
453
454 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
455 if (errChk == 0) return -3; //preamble not found
456 if (*size != 96) return -2; //should have found 96 bits
457 //check first 6 spacer bits to verify format
458 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
459 //confirmed proper separator bits found
460 //return start position
461 return (int) startIdx;
462 }
463 return -5;
464}
465
ba1a299c 466//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
f822a063 467size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
eb191de6 468{
2eec55c8 469 size_t last_transition = 0;
470 size_t idx = 1;
ac3ba7ee 471 //uint32_t maxVal=0;
ba1a299c 472 if (fchigh==0) fchigh=10;
473 if (fclow==0) fclow=8;
84871873 474 //set the threshold close to 0 (graph) or 128 std to avoid static
475 uint8_t threshold_value = 123;
f4eadf8a 476 size_t preLastSample = 0;
477 size_t LastSample = 0;
478 size_t currSample = 0;
ba1a299c 479 // sync to first lo-hi transition, and threshold
480
481 // Need to threshold first sample
6fe5c94b 482 // skip 160 samples to allow antenna/samples to settle
483 if(dest[160] < threshold_value) dest[0] = 0;
ba1a299c 484 else dest[0] = 1;
485
486 size_t numBits = 0;
487 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
63744b56 488 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
ba1a299c 489 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
6fe5c94b 490 for(idx = 161; idx < size-20; idx++) {
ba1a299c 491 // threshold current value
492
493 if (dest[idx] < threshold_value) dest[idx] = 0;
494 else dest[idx] = 1;
495
496 // Check for 0->1 transition
497 if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
f4eadf8a 498 preLastSample = LastSample;
499 LastSample = currSample;
500 currSample = idx-last_transition;
6fe5c94b 501 if (currSample < (fclow-2)){ //0-5 = garbage noise (or 0-3)
ba1a299c 502 //do nothing with extra garbage
6fe5c94b 503 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves or 3-6 = 5
db829602 504 if (LastSample > (fchigh-2) && (preLastSample < (fchigh-1) || preLastSample == 0 )){
6fe5c94b 505 dest[numBits-1]=1; //correct previous 9 wave surrounded by 8 waves
f4eadf8a 506 }
2eec55c8 507 dest[numBits++]=1;
f4eadf8a 508
db829602 509 } else if (currSample > (fchigh) && !numBits) { //12 + and first bit = garbage
13d77ef9 510 //do nothing with beginning garbage
f4eadf8a 511 } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's
512 dest[numBits++]=1;
513 } else { //9+ = 10 sample waves
2eec55c8 514 dest[numBits++]=0;
ba1a299c 515 }
516 last_transition = idx;
ba1a299c 517 }
518 }
519 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
eb191de6 520}
521
ba1a299c 522//translate 11111100000 to 10
2eec55c8 523size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
e0165dcf 524 uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 525{
ba1a299c 526 uint8_t lastval=dest[0];
2eec55c8 527 size_t idx=0;
ba1a299c 528 size_t numBits=0;
529 uint32_t n=1;
ba1a299c 530 for( idx=1; idx < size; idx++) {
13d77ef9 531 n++;
2eec55c8 532 if (dest[idx]==lastval) continue;
533
ba1a299c 534 //if lastval was 1, we have a 1->0 crossing
13d77ef9 535 if (dest[idx-1]==1) {
6fe5c94b 536 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 537 } else {// 0->1 crossing
75cbbe9a 538 n = (n * fchigh + rfLen/2) / rfLen;
ba1a299c 539 }
540 if (n == 0) n = 1;
541
2eec55c8 542 memset(dest+numBits, dest[idx-1]^invert , n);
543 numBits += n;
ba1a299c 544 n=0;
545 lastval=dest[idx];
546 }//end for
13d77ef9 547 // if valid extra bits at the end were all the same frequency - add them in
75cbbe9a 548 if (n > rfLen/fchigh) {
13d77ef9 549 if (dest[idx-2]==1) {
75cbbe9a 550 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 551 } else {
75cbbe9a 552 n = (n * fchigh + rfLen/2) / rfLen;
13d77ef9 553 }
2eec55c8 554 memset(dest+numBits, dest[idx-1]^invert , n);
13d77ef9 555 numBits += n;
556 }
ba1a299c 557 return numBits;
eb191de6 558}
6fe5c94b 559
eb191de6 560//by marshmellow (from holiman's base)
561// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
f822a063 562int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
eb191de6 563{
ba1a299c 564 // FSK demodulator
565 size = fsk_wave_demod(dest, size, fchigh, fclow);
2eec55c8 566 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow);
ba1a299c 567 return size;
eb191de6 568}
a1d17964 569
eb191de6 570// loop to get raw HID waveform then FSK demodulate the TAG ID from it
ec75f5c1 571int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
eb191de6 572{
e0165dcf 573 if (justNoise(dest, *size)) return -1;
574
575 size_t numStart=0, size2=*size, startIdx=0;
576 // FSK demodulator
577 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
2eec55c8 578 if (*size < 96*2) return -2;
e0165dcf 579 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
580 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
581 // find bitstring in array
582 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
583 if (errChk == 0) return -3; //preamble not found
584
585 numStart = startIdx + sizeof(preamble);
586 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
587 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
588 if (dest[idx] == dest[idx+1]){
589 return -4; //not manchester data
590 }
591 *hi2 = (*hi2<<1)|(*hi>>31);
592 *hi = (*hi<<1)|(*lo>>31);
593 //Then, shift in a 0 or one into low
594 if (dest[idx] && !dest[idx+1]) // 1 0
595 *lo=(*lo<<1)|1;
596 else // 0 1
597 *lo=(*lo<<1)|0;
598 }
599 return (int)startIdx;
eb191de6 600}
601
ec75f5c1 602// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
a1d17964 603int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
ec75f5c1 604{
a1d17964 605 if (justNoise(dest, *size)) return -1;
606
607 size_t numStart=0, size2=*size, startIdx=0;
ec75f5c1 608 // FSK demodulator
a1d17964 609 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
610 if (*size < 96) return -2;
ec75f5c1 611
a1d17964 612 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
613 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
614
615 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
616 if (errChk == 0) return -3; //preamble not found
617
618 numStart = startIdx + sizeof(preamble);
619 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
620 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
621 if (dest[idx] == dest[idx+1])
622 return -4; //not manchester data
623 *hi2 = (*hi2<<1)|(*hi>>31);
624 *hi = (*hi<<1)|(*lo>>31);
625 //Then, shift in a 0 or one into low
626 if (dest[idx] && !dest[idx+1]) // 1 0
627 *lo=(*lo<<1)|1;
628 else // 0 1
629 *lo=(*lo<<1)|0;
ec75f5c1 630 }
a1d17964 631 return (int)startIdx;
ec75f5c1 632}
633
eb191de6 634int IOdemodFSK(uint8_t *dest, size_t size)
635{
a1d17964 636 if (justNoise(dest, size)) return -1;
ba1a299c 637 //make sure buffer has data
a1d17964 638 if (size < 66*64) return -2;
ba1a299c 639 // FSK demodulator
a1d17964 640 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
641 if (size < 65) return -3; //did we get a good demod?
ba1a299c 642 //Index map
643 //0 10 20 30 40 50 60
644 //| | | | | | |
645 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
646 //-----------------------------------------------------------------------------
647 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
648 //
649 //XSF(version)facility:codeone+codetwo
650 //Handle the data
a1d17964 651 size_t startIdx = 0;
652 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
653 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
654 if (errChk == 0) return -4; //preamble not found
eb191de6 655
a1d17964 656 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
657 //confirmed proper separator bits found
658 //return start position
659 return (int) startIdx;
1e090a61 660 }
a1d17964 661 return -5;
415274a7 662}
663
664// by marshmellow
665// find viking preamble 0xF200 in already demoded data
666int VikingDemod_AM(uint8_t *dest, size_t *size) {
415274a7 667 //make sure buffer has data
668 if (*size < 64*2) return -2;
669
670 size_t startIdx = 0;
671 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};
672 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
673 if (errChk == 0) return -4; //preamble not found
3ea7254a 674 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
675 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
676 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
677 if ( checkCalc != 0xA8 ) return -5;
14331320 678 if (*size != 64) return -6;
415274a7 679 //return start position
680 return (int) startIdx;
1e090a61 681}
682
04bb0567 683// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
684// BitStream must contain previously askrawdemod and biphasedemoded data
b2c330b3 685int FDXBdemodBI(uint8_t *dest, size_t *size)
04bb0567 686{
687 //make sure buffer has enough data
688 if (*size < 128) return -1;
689
690 size_t startIdx = 0;
691 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
692
693 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
694 if (errChk == 0) return -2; //preamble not found
695 return (int)startIdx;
696}
697
1e090a61 698// by marshmellow
699// FSK Demod then try to locate an AWID ID
a1d17964 700int AWIDdemodFSK(uint8_t *dest, size_t *size)
1e090a61 701{
a1d17964 702 //make sure buffer has enough data
703 if (*size < 96*50) return -1;
704
705 if (justNoise(dest, *size)) return -2;
1e090a61 706
707 // FSK demodulator
a1d17964 708 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
709 if (*size < 96) return -3; //did we get a good demod?
710
711 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
712 size_t startIdx = 0;
713 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
714 if (errChk == 0) return -4; //preamble not found
715 if (*size != 96) return -5;
716 return (int)startIdx;
1e090a61 717}
718
719// by marshmellow
6fe5c94b 720// FSK Demod then try to locate a Farpointe Data (pyramid) ID
a1d17964 721int PyramiddemodFSK(uint8_t *dest, size_t *size)
1e090a61 722{
f3bf15e4 723 //make sure buffer has data
724 if (*size < 128*50) return -5;
a1d17964 725
f3bf15e4 726 //test samples are not just noise
727 if (justNoise(dest, *size)) return -1;
1e090a61 728
f3bf15e4 729 // FSK demodulator
730 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
731 if (*size < 128) return -2; //did we get a good demod?
a1d17964 732
f3bf15e4 733 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
a1d17964 734 size_t startIdx = 0;
735 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
736 if (errChk == 0) return -4; //preamble not found
737 if (*size != 128) return -3;
738 return (int)startIdx;
1e090a61 739}
740
fef74fdc 741// by marshmellow
742// to detect a wave that has heavily clipped (clean) samples
cc15a118 743uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
6de43508 744{
6fe5c94b 745 bool allArePeaks = true;
6de43508 746 uint16_t cntPeaks=0;
db829602 747 size_t loopEnd = 512+160;
1fbf8956 748 if (loopEnd > size) loopEnd = size;
db829602 749 for (size_t i=160; i<loopEnd; i++){
6de43508 750 if (dest[i]>low && dest[i]<high)
6fe5c94b 751 allArePeaks = false;
6de43508 752 else
753 cntPeaks++;
754 }
6fe5c94b 755 if (!allArePeaks){
756 if (cntPeaks > 300) return true;
6de43508 757 }
6fe5c94b 758 return allArePeaks;
6de43508 759}
2eec55c8 760// by marshmellow
761// to help detect clocks on heavily clipped samples
cc15a118 762// based on count of low to low
763int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
13d77ef9 764{
cc15a118 765 uint8_t fndClk[] = {8,16,32,40,50,64,128};
766 size_t startwave;
db829602 767 size_t i = 100;
cc15a118 768 size_t minClk = 255;
769 // get to first full low to prime loop and skip incomplete first pulse
770 while ((dest[i] < high) && (i < size))
771 ++i;
772 while ((dest[i] > low) && (i < size))
773 ++i;
774
775 // loop through all samples
776 while (i < size) {
777 // measure from low to low
778 while ((dest[i] > low) && (i < size))
779 ++i;
780 startwave= i;
781 while ((dest[i] < high) && (i < size))
782 ++i;
783 while ((dest[i] > low) && (i < size))
784 ++i;
785 //get minimum measured distance
786 if (i-startwave < minClk && i < size)
787 minClk = i - startwave;
13d77ef9 788 }
cc15a118 789 // set clock
709665b5 790 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
cc15a118 791 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
792 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1)
793 return fndClk[clkCnt];
13d77ef9 794 }
cc15a118 795 return 0;
13d77ef9 796}
797
eb191de6 798// by marshmellow
799// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
800// maybe somehow adjust peak trimming value based on samples to fix?
6de43508 801// return start index of best starting position for that clock and return clock (by reference)
802int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
eb191de6 803{
6e984446 804 size_t i=1;
cc15a118 805 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
806 uint8_t clkEnd = 9;
2eec55c8 807 uint8_t loopCnt = 255; //don't need to loop through entire array...
db829602 808 if (size <= loopCnt+60) return -1; //not enough samples
809 size -= 60; //sometimes there is a strange end wave - filter out this....
6e984446 810 //if we already have a valid clock
811 uint8_t clockFnd=0;
cc15a118 812 for (;i<clkEnd;++i)
813 if (clk[i] == *clock) clockFnd = i;
6e984446 814 //clock found but continue to find best startpos
e0165dcf 815
816 //get high and low peak
817 int peak, low;
2eec55c8 818 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
e0165dcf 819
820 //test for large clean peaks
cc15a118 821 if (!clockFnd){
822 if (DetectCleanAskWave(dest, size, peak, low)==1){
823 int ans = DetectStrongAskClock(dest, size, peak, low);
709665b5 824 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d",ans);
cc15a118 825 for (i=clkEnd-1; i>0; i--){
826 if (clk[i] == ans) {
827 *clock = ans;
828 //clockFnd = i;
829 return 0; // for strong waves i don't use the 'best start position' yet...
830 //break; //clock found but continue to find best startpos [not yet]
831 }
e0165dcf 832 }
833 }
834 }
2eec55c8 835 uint8_t ii;
836 uint8_t clkCnt, tol = 0;
837 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
838 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
839 size_t errCnt = 0;
840 size_t arrLoc, loopEnd;
6e984446 841
cc15a118 842 if (clockFnd>0) {
843 clkCnt = clockFnd;
844 clkEnd = clockFnd+1;
845 }
846 else clkCnt=1;
847
848 //test each valid clock from smallest to greatest to see which lines up
849 for(; clkCnt < clkEnd; clkCnt++){
fef74fdc 850 if (clk[clkCnt] <= 32){
e0165dcf 851 tol=1;
852 }else{
853 tol=0;
854 }
2767fc02 855 //if no errors allowed - keep start within the first clock
cc15a118 856 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
e0165dcf 857 bestErr[clkCnt]=1000;
6e984446 858 //try lining up the peaks by moving starting point (try first few clocks)
cc15a118 859 for (ii=0; ii < loopCnt; ii++){
2eec55c8 860 if (dest[ii] < peak && dest[ii] > low) continue;
861
862 errCnt=0;
863 // now that we have the first one lined up test rest of wave array
864 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
865 for (i=0; i < loopEnd; ++i){
866 arrLoc = ii + (i * clk[clkCnt]);
867 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
868 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
869 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
870 }else{ //error no peak detected
871 errCnt++;
e0165dcf 872 }
873 }
cc15a118 874 //if we found no errors then we can stop here and a low clock (common clocks)
2eec55c8 875 // this is correct one - return this clock
709665b5 876 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
cc15a118 877 if(errCnt==0 && clkCnt<7) {
878 if (!clockFnd) *clock = clk[clkCnt];
2eec55c8 879 return ii;
880 }
881 //if we found errors see if it is lowest so far and save it as best run
882 if(errCnt<bestErr[clkCnt]){
883 bestErr[clkCnt]=errCnt;
884 bestStart[clkCnt]=ii;
885 }
e0165dcf 886 }
887 }
cc15a118 888 uint8_t iii;
e0165dcf 889 uint8_t best=0;
cc15a118 890 for (iii=1; iii<clkEnd; ++iii){
2eec55c8 891 if (bestErr[iii] < bestErr[best]){
892 if (bestErr[iii] == 0) bestErr[iii]=1;
e0165dcf 893 // current best bit to error ratio vs new bit to error ratio
2eec55c8 894 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
e0165dcf 895 best = iii;
896 }
897 }
709665b5 898 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 899 }
cc15a118 900 if (!clockFnd) *clock = clk[best];
e0165dcf 901 return bestStart[best];
eb191de6 902}
ba1a299c 903
904//by marshmellow
6de43508 905//detect psk clock by reading each phase shift
906// a phase shift is determined by measuring the sample length of each wave
907int DetectPSKClock(uint8_t dest[], size_t size, int clock)
ba1a299c 908{
e0165dcf 909 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
910 uint16_t loopCnt = 4096; //don't need to loop through entire array...
911 if (size == 0) return 0;
db829602 912 if (size<loopCnt) loopCnt = size-20;
e0165dcf 913
914 //if we already have a valid clock quit
915 size_t i=1;
916 for (; i < 8; ++i)
917 if (clk[i] == clock) return clock;
918
919 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
920 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
921 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
922 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
923 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
2eec55c8 924 fc = countFC(dest, size, 0);
925 if (fc!=2 && fc!=4 && fc!=8) return -1;
709665b5 926 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
e0165dcf 927
928 //find first full wave
db829602 929 for (i=160; i<loopCnt; i++){
e0165dcf 930 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
931 if (waveStart == 0) {
932 waveStart = i+1;
db829602 933 //prnt("DEBUG: waveStart: %d",waveStart);
e0165dcf 934 } else {
935 waveEnd = i+1;
db829602 936 //prnt("DEBUG: waveEnd: %d",waveEnd);
e0165dcf 937 waveLenCnt = waveEnd-waveStart;
938 if (waveLenCnt > fc){
939 firstFullWave = waveStart;
940 fullWaveLen=waveLenCnt;
941 break;
942 }
943 waveStart=0;
944 }
945 }
946 }
709665b5 947 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 948
949 //test each valid clock from greatest to smallest to see which lines up
950 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
951 lastClkBit = firstFullWave; //set end of wave as clock align
952 waveStart = 0;
953 errCnt=0;
954 peakcnt=0;
709665b5 955 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
e0165dcf 956
957 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
958 //top edge of wave = start of new wave
959 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
960 if (waveStart == 0) {
961 waveStart = i+1;
962 waveLenCnt=0;
963 } else { //waveEnd
964 waveEnd = i+1;
965 waveLenCnt = waveEnd-waveStart;
966 if (waveLenCnt > fc){
967 //if this wave is a phase shift
709665b5 968 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 969 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
970 peakcnt++;
971 lastClkBit+=clk[clkCnt];
972 } else if (i<lastClkBit+8){
973 //noise after a phase shift - ignore
974 } else { //phase shift before supposed to based on clock
975 errCnt++;
976 }
977 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
978 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
979 }
980 waveStart=i+1;
981 }
982 }
983 }
984 if (errCnt == 0){
985 return clk[clkCnt];
986 }
987 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
988 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
989 }
990 //all tested with errors
991 //return the highest clk with the most peaks found
992 uint8_t best=7;
993 for (i=7; i>=1; i--){
994 if (peaksdet[i] > peaksdet[best]) {
995 best = i;
996 }
709665b5 997 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
e0165dcf 998 }
999 return clk[best];
ba1a299c 1000}
1001
db829602 1002int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1003 //find shortest transition from high to low
1004 size_t i = 0;
1005 size_t transition1 = 0;
1006 int lowestTransition = 255;
6fe5c94b 1007 bool lastWasHigh = false;
1008
1009 //find first valid beginning of a high or low wave
1010 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1011 ++i;
1012 while ((dest[i] < peak && dest[i] > low) && (i < size))
1013 ++i;
1014 lastWasHigh = (dest[i] >= peak);
1015
db829602 1016 if (i==size) return 0;
1017 transition1 = i;
1018
1019 for (;i < size; i++) {
1020 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1021 lastWasHigh = (dest[i] >= peak);
1022 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1023 transition1 = i;
1024 }
1025 }
1026 if (lowestTransition == 255) lowestTransition = 0;
709665b5 1027 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
db829602 1028 return lowestTransition;
1029}
1030
6de43508 1031//by marshmellow
1032//detect nrz clock by reading #peaks vs no peaks(or errors)
1033int DetectNRZClock(uint8_t dest[], size_t size, int clock)
ba1a299c 1034{
2eec55c8 1035 size_t i=0;
1036 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1037 size_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1038 if (size == 0) return 0;
db829602 1039 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1040 //if we already have a valid clock quit
1041 for (; i < 8; ++i)
1042 if (clk[i] == clock) return clock;
1043
1044 //get high and low peak
1045 int peak, low;
2eec55c8 1046 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
e0165dcf 1047
db829602 1048 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
2eec55c8 1049 size_t ii;
e0165dcf 1050 uint8_t clkCnt;
1051 uint8_t tol = 0;
db829602 1052 uint16_t smplCnt = 0;
1053 int16_t peakcnt = 0;
1054 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1055 uint16_t maxPeak = 255;
6fe5c94b 1056 bool firstpeak = false;
e0165dcf 1057 //test for large clipped waves
1058 for (i=0; i<loopCnt; i++){
1059 if (dest[i] >= peak || dest[i] <= low){
db829602 1060 if (!firstpeak) continue;
1061 smplCnt++;
e0165dcf 1062 } else {
6fe5c94b 1063 firstpeak=true;
db829602 1064 if (smplCnt > 6 ){
1065 if (maxPeak > smplCnt){
1066 maxPeak = smplCnt;
1067 //prnt("maxPk: %d",maxPeak);
1068 }
1069 peakcnt++;
1070 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1071 smplCnt=0;
e0165dcf 1072 }
e0165dcf 1073 }
1074 }
6fe5c94b 1075 bool errBitHigh = 0;
1076 bool bitHigh = 0;
1077 uint8_t ignoreCnt = 0;
1078 uint8_t ignoreWindow = 4;
1079 bool lastPeakHigh = 0;
1080 int lastBit = 0;
e0165dcf 1081 peakcnt=0;
1082 //test each valid clock from smallest to greatest to see which lines up
1083 for(clkCnt=0; clkCnt < 8; ++clkCnt){
db829602 1084 //ignore clocks smaller than smallest peak
1085 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
e0165dcf 1086 //try lining up the peaks by moving starting point (try first 256)
db829602 1087 for (ii=20; ii < loopCnt; ++ii){
e0165dcf 1088 if ((dest[ii] >= peak) || (dest[ii] <= low)){
6fe5c94b 1089 peakcnt = 0;
1090 bitHigh = false;
1091 ignoreCnt = 0;
1092 lastBit = ii-clk[clkCnt];
db829602 1093 //loop through to see if this start location works
1094 for (i = ii; i < size-20; ++i) {
6fe5c94b 1095 //if we are at a clock bit
db829602 1096 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1097 //test high/low
1098 if (dest[i] >= peak || dest[i] <= low) {
6fe5c94b 1099 //if same peak don't count it
1100 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1101 peakcnt++;
1102 }
1103 lastPeakHigh = (dest[i] >= peak);
1104 bitHigh = true;
1105 errBitHigh = false;
db829602 1106 ignoreCnt = ignoreWindow;
1107 lastBit += clk[clkCnt];
db829602 1108 } else if (i == lastBit + clk[clkCnt] + tol) {
1109 lastBit += clk[clkCnt];
db829602 1110 }
1111 //else if not a clock bit and no peaks
1112 } else if (dest[i] < peak && dest[i] > low){
db829602 1113 if (ignoreCnt==0){
6fe5c94b 1114 bitHigh=false;
1115 if (errBitHigh==true) peakcnt--;
1116 errBitHigh=false;
db829602 1117 } else {
1118 ignoreCnt--;
1119 }
1120 // else if not a clock bit but we have a peak
6fe5c94b 1121 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
db829602 1122 //error bar found no clock...
6fe5c94b 1123 errBitHigh=true;
e0165dcf 1124 }
1125 }
1126 if(peakcnt>peaksdet[clkCnt]) {
1127 peaksdet[clkCnt]=peakcnt;
1128 }
1129 }
1130 }
1131 }
1132 int iii=7;
2eec55c8 1133 uint8_t best=0;
e0165dcf 1134 for (iii=7; iii > 0; iii--){
6fe5c94b 1135 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1136 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
db829602 1137 best = iii;
1138 }
6fe5c94b 1139 } else if (peaksdet[iii] > peaksdet[best]){
1140 best = iii;
e0165dcf 1141 }
709665b5 1142 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 1143 }
db829602 1144
e0165dcf 1145 return clk[best];
ba1a299c 1146}
1147
04d2721b 1148// by marshmellow
1149// convert psk1 demod to psk2 demod
1150// only transition waves are 1s
1151void psk1TOpsk2(uint8_t *BitStream, size_t size)
1152{
1153 size_t i=1;
1154 uint8_t lastBit=BitStream[0];
1155 for (; i<size; i++){
2767fc02 1156 if (BitStream[i]==7){
7a8a982b 1157 //ignore errors
1158 } else if (lastBit!=BitStream[i]){
04d2721b 1159 lastBit=BitStream[i];
1160 BitStream[i]=1;
1161 } else {
1162 BitStream[i]=0;
1163 }
1164 }
1165 return;
1166}
ba1a299c 1167
3bc66a96 1168// by marshmellow
1169// convert psk2 demod to psk1 demod
1170// from only transition waves are 1s to phase shifts change bit
1171void psk2TOpsk1(uint8_t *BitStream, size_t size)
1172{
712ebfa6 1173 uint8_t phase=0;
1174 for (size_t i=0; i<size; i++){
1175 if (BitStream[i]==1){
3bc66a96 1176 phase ^=1;
1177 }
1178 BitStream[i]=phase;
1179 }
1180 return;
1181}
1182
04d2721b 1183// redesigned by marshmellow adjusted from existing decode functions
1184// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
ba1a299c 1185int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1186{
1187 //26 bit 40134 format (don't know other formats)
14331320 1188 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};
1189 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};
1190 size_t startidx = 0;
1191 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1192 // if didn't find preamble try again inverting
1193 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1194 *invert ^= 1;
1195 }
1196 if (*size != 64 && *size != 224) return -2;
1197 if (*invert==1)
1198 for (size_t i = startidx; i < *size; i++)
1199 bitStream[i] ^= 1;
ba1a299c 1200
14331320 1201 return (int) startidx;
ba1a299c 1202}
1203
d1869c33 1204// by marshmellow - demodulate NRZ wave - requires a read with strong signal
04d2721b 1205// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
db829602 1206int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert){
e0165dcf 1207 if (justNoise(dest, *size)) return -1;
1208 *clk = DetectNRZClock(dest, *size, *clk);
1209 if (*clk==0) return -2;
2eec55c8 1210 size_t i, gLen = 4096;
db829602 1211 if (gLen>*size) gLen = *size-20;
e0165dcf 1212 int high, low;
1213 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
db829602 1214
1215 uint8_t bit=0;
1216 //convert wave samples to 1's and 0's
1217 for(i=20; i < *size-20; i++){
1218 if (dest[i] >= high) bit = 1;
1219 if (dest[i] <= low) bit = 0;
1220 dest[i] = bit;
e0165dcf 1221 }
db829602 1222 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1223 size_t lastBit = 0;
1224 size_t numBits = 0;
1225 for(i=21; i < *size-20; i++) {
1226 //if transition detected or large number of same bits - store the passed bits
1227 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1228 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1229 numBits += (i - lastBit + (*clk/4)) / *clk;
1230 lastBit = i-1;
e0165dcf 1231 }
e0165dcf 1232 }
db829602 1233 *size = numBits;
1234 return 0;
ba1a299c 1235}
1236
1e090a61 1237//by marshmellow
03e6bb4a 1238//detects the bit clock for FSK given the high and low Field Clocks
1239uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow)
1e090a61 1240{
e0165dcf 1241 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1242 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1243 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1244 uint8_t rfLensFnd = 0;
2eec55c8 1245 uint8_t lastFCcnt = 0;
1246 uint16_t fcCounter = 0;
e0165dcf 1247 uint16_t rfCounter = 0;
1248 uint8_t firstBitFnd = 0;
1249 size_t i;
1250 if (size == 0) return 0;
1251
6fe5c94b 1252 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
e0165dcf 1253 rfLensFnd=0;
1254 fcCounter=0;
1255 rfCounter=0;
1256 firstBitFnd=0;
1257 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
6fe5c94b 1258 // prime i to first peak / up transition
1259 for (i = 160; i < size-20; i++)
e0165dcf 1260 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1261 break;
1262
6fe5c94b 1263 for (; i < size-20; i++){
2eec55c8 1264 fcCounter++;
1265 rfCounter++;
1266
1267 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1268 continue;
1269 // else new peak
1270 // if we got less than the small fc + tolerance then set it to the small fc
1271 if (fcCounter < fcLow+fcTol)
1272 fcCounter = fcLow;
1273 else //set it to the large fc
1274 fcCounter = fcHigh;
1275
1276 //look for bit clock (rf/xx)
1277 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1278 //not the same size as the last wave - start of new bit sequence
1279 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1280 for (int ii=0; ii<15; ii++){
6fe5c94b 1281 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
2eec55c8 1282 rfCnts[ii]++;
1283 rfCounter = 0;
1284 break;
e0165dcf 1285 }
e0165dcf 1286 }
2eec55c8 1287 if (rfCounter > 0 && rfLensFnd < 15){
1288 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1289 rfCnts[rfLensFnd]++;
1290 rfLens[rfLensFnd++] = rfCounter;
1291 }
1292 } else {
1293 firstBitFnd++;
e0165dcf 1294 }
2eec55c8 1295 rfCounter=0;
1296 lastFCcnt=fcCounter;
e0165dcf 1297 }
2eec55c8 1298 fcCounter=0;
e0165dcf 1299 }
1300 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1301
1302 for (i=0; i<15; i++){
e0165dcf 1303 //get highest 2 RF values (might need to get more values to compare or compare all?)
1304 if (rfCnts[i]>rfCnts[rfHighest]){
1305 rfHighest3=rfHighest2;
1306 rfHighest2=rfHighest;
1307 rfHighest=i;
1308 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1309 rfHighest3=rfHighest2;
1310 rfHighest2=i;
1311 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1312 rfHighest3=i;
1313 }
709665b5 1314 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
e0165dcf 1315 }
1316 // set allowed clock remainder tolerance to be 1 large field clock length+1
1317 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1318 uint8_t tol1 = fcHigh+1;
1319
709665b5 1320 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
e0165dcf 1321
1322 // loop to find the highest clock that has a remainder less than the tolerance
1323 // compare samples counted divided by
6fe5c94b 1324 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
e0165dcf 1325 int ii=7;
6fe5c94b 1326 for (; ii>=2; ii--){
e0165dcf 1327 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1328 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1329 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
709665b5 1330 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
e0165dcf 1331 break;
1332 }
1333 }
1334 }
1335 }
1336
1337 if (ii<0) return 0; // oops we went too far
1338
1339 return clk[ii];
03e6bb4a 1340}
1e090a61 1341
03e6bb4a 1342//by marshmellow
1343//countFC is to detect the field clock lengths.
1344//counts and returns the 2 most common wave lengths
6de43508 1345//mainly used for FSK field clock detection
2eec55c8 1346uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
03e6bb4a 1347{
6fe5c94b 1348 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1349 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
e0165dcf 1350 uint8_t fcLensFnd = 0;
1351 uint8_t lastFCcnt=0;
2eec55c8 1352 uint8_t fcCounter = 0;
e0165dcf 1353 size_t i;
1354 if (size == 0) return 0;
1355
1356 // prime i to first up transition
6fe5c94b 1357 for (i = 160; i < size-20; i++)
e0165dcf 1358 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1359 break;
1360
6fe5c94b 1361 for (; i < size-20; i++){
e0165dcf 1362 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1363 // new up transition
1364 fcCounter++;
2eec55c8 1365 if (fskAdj){
1366 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1367 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1368 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1369 if ((fcCounter==9) || fcCounter==4) fcCounter++;
e0165dcf 1370 // save last field clock count (fc/xx)
2eec55c8 1371 lastFCcnt = fcCounter;
1372 }
e0165dcf 1373 // find which fcLens to save it to:
6fe5c94b 1374 for (int ii=0; ii<15; ii++){
e0165dcf 1375 if (fcLens[ii]==fcCounter){
1376 fcCnts[ii]++;
1377 fcCounter=0;
1378 break;
1379 }
1380 }
6fe5c94b 1381 if (fcCounter>0 && fcLensFnd<15){
e0165dcf 1382 //add new fc length
1383 fcCnts[fcLensFnd]++;
1384 fcLens[fcLensFnd++]=fcCounter;
1385 }
1386 fcCounter=0;
1387 } else {
1388 // count sample
1389 fcCounter++;
1390 }
1391 }
1392
6fe5c94b 1393 uint8_t best1=14, best2=14, best3=14;
e0165dcf 1394 uint16_t maxCnt1=0;
1395 // go through fclens and find which ones are bigest 2
6fe5c94b 1396 for (i=0; i<15; i++){
e0165dcf 1397 // get the 3 best FC values
1398 if (fcCnts[i]>maxCnt1) {
1399 best3=best2;
1400 best2=best1;
1401 maxCnt1=fcCnts[i];
1402 best1=i;
1403 } else if(fcCnts[i]>fcCnts[best2]){
1404 best3=best2;
1405 best2=i;
1406 } else if(fcCnts[i]>fcCnts[best3]){
1407 best3=i;
1408 }
709665b5 1409 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 1410 }
6fe5c94b 1411 if (fcLens[best1]==0) return 0;
e0165dcf 1412 uint8_t fcH=0, fcL=0;
1413 if (fcLens[best1]>fcLens[best2]){
1414 fcH=fcLens[best1];
1415 fcL=fcLens[best2];
1416 } else{
1417 fcH=fcLens[best2];
1418 fcL=fcLens[best1];
1419 }
709665b5 1420 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1421 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]);
1422 return 0; //lots of waves not psk or fsk
1423 }
e0165dcf 1424 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1425
1426 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
2eec55c8 1427 if (fskAdj) return fcs;
1428 return fcLens[best1];
6de43508 1429}
1430
1431//by marshmellow - demodulate PSK1 wave
1432//uses wave lengths (# Samples)
1433int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert)
1434{
e0165dcf 1435 if (size == 0) return -1;
2eec55c8 1436 uint16_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1437 if (*size<loopCnt) loopCnt = *size;
1438
db829602 1439 size_t numBits=0;
e0165dcf 1440 uint8_t curPhase = *invert;
1441 size_t i, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
1442 uint8_t fc=0, fullWaveLen=0, tol=1;
1443 uint16_t errCnt=0, waveLenCnt=0;
2eec55c8 1444 fc = countFC(dest, *size, 0);
e0165dcf 1445 if (fc!=2 && fc!=4 && fc!=8) return -1;
1446 //PrintAndLog("DEBUG: FC: %d",fc);
1447 *clock = DetectPSKClock(dest, *size, *clock);
2eec55c8 1448 if (*clock == 0) return -1;
e0165dcf 1449 int avgWaveVal=0, lastAvgWaveVal=0;
1450 //find first phase shift
1451 for (i=0; i<loopCnt; i++){
1452 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1453 waveEnd = i+1;
1454 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1455 waveLenCnt = waveEnd-waveStart;
db829602 1456 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+2)){ //not first peak and is a large wave but not out of whack
e0165dcf 1457 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1458 firstFullWave = waveStart;
1459 fullWaveLen=waveLenCnt;
1460 //if average wave value is > graph 0 then it is an up wave or a 1
2eec55c8 1461 if (lastAvgWaveVal > 123) curPhase ^= 1; //fudge graph 0 a little 123 vs 128
e0165dcf 1462 break;
1463 }
1464 waveStart = i+1;
1465 avgWaveVal = 0;
1466 }
2eec55c8 1467 avgWaveVal += dest[i+2];
e0165dcf 1468 }
db829602 1469 if (firstFullWave == 0) {
1470 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1471 // so skip a little to ensure we are past any Start Signal
1472 firstFullWave = 160;
1473 memset(dest, curPhase, firstFullWave / *clock);
1474 } else {
1475 memset(dest, curPhase^1, firstFullWave / *clock);
1476 }
1477 //advance bits
1478 numBits += (firstFullWave / *clock);
1479 //set start of wave as clock align
1480 lastClkBit = firstFullWave;
e0165dcf 1481 //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 1482 //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
1483 waveStart = 0;
e0165dcf 1484 dest[numBits++] = curPhase; //set first read bit
2eec55c8 1485 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
e0165dcf 1486 //top edge of wave = start of new wave
1487 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1488 if (waveStart == 0) {
1489 waveStart = i+1;
2eec55c8 1490 waveLenCnt = 0;
e0165dcf 1491 avgWaveVal = dest[i+1];
1492 } else { //waveEnd
1493 waveEnd = i+1;
1494 waveLenCnt = waveEnd-waveStart;
1495 lastAvgWaveVal = avgWaveVal/waveLenCnt;
1496 if (waveLenCnt > fc){
1497 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
2eec55c8 1498 //this wave is a phase shift
e0165dcf 1499 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1500 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
2eec55c8 1501 curPhase ^= 1;
e0165dcf 1502 dest[numBits++] = curPhase;
1503 lastClkBit += *clock;
2eec55c8 1504 } else if (i < lastClkBit+10+fc){
e0165dcf 1505 //noise after a phase shift - ignore
1506 } else { //phase shift before supposed to based on clock
1507 errCnt++;
2767fc02 1508 dest[numBits++] = 7;
e0165dcf 1509 }
1510 } else if (i+1 > lastClkBit + *clock + tol + fc){
1511 lastClkBit += *clock; //no phase shift but clock bit
1512 dest[numBits++] = curPhase;
1513 }
2eec55c8 1514 avgWaveVal = 0;
1515 waveStart = i+1;
e0165dcf 1516 }
1517 }
2eec55c8 1518 avgWaveVal += dest[i+1];
e0165dcf 1519 }
1520 *size = numBits;
1521 return errCnt;
6de43508 1522}
d1869c33 1523
1524//by marshmellow
1525//attempt to identify a Sequence Terminator in ASK modulated raw wave
1526bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1527 size_t bufsize = *size;
1528 //need to loop through all samples and identify our clock, look for the ST pattern
1529 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1530 int clk = 0;
1531 int tol = 0;
b96bcc79 1532 int i, j, skip, start, end, low, high, minClk, waveStart;
d1869c33 1533 bool complete = false;
1534 int tmpbuff[bufsize / 64];
b96bcc79 1535 int waveLen[bufsize / 64];
d1869c33 1536 size_t testsize = (bufsize < 512) ? bufsize : 512;
b96bcc79 1537 int phaseoff = 0;
d1869c33 1538 high = low = 128;
1539 memset(tmpbuff, 0, sizeof(tmpbuff));
1540
1541 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1542 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1543 return false; //just noise
1544 }
d1869c33 1545 i = 0;
1546 j = 0;
1547 minClk = 255;
1548 // get to first full low to prime loop and skip incomplete first pulse
1549 while ((buffer[i] < high) && (i < bufsize))
1550 ++i;
1551 while ((buffer[i] > low) && (i < bufsize))
1552 ++i;
1553 skip = i;
1554
1555 // populate tmpbuff buffer with pulse lengths
1556 while (i < bufsize) {
1557 // measure from low to low
1558 while ((buffer[i] > low) && (i < bufsize))
1559 ++i;
1560 start= i;
1561 while ((buffer[i] < high) && (i < bufsize))
1562 ++i;
b96bcc79 1563 //first high point for this wave
1564 waveStart = i;
d1869c33 1565 while ((buffer[i] > low) && (i < bufsize))
1566 ++i;
1567 if (j >= (bufsize/64)) {
1568 break;
1569 }
b96bcc79 1570 waveLen[j] = i - waveStart; //first high to first low
d1869c33 1571 tmpbuff[j++] = i - start;
1572 if (i-start < minClk && i < bufsize) {
1573 minClk = i - start;
1574 }
1575 }
1576 // set clock - might be able to get this externally and remove this work...
1577 if (!clk) {
1578 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1579 tol = fndClk[clkCnt]/8;
1580 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1581 clk=fndClk[clkCnt];
1582 break;
1583 }
1584 }
1585 // clock not found - ERROR
1586 if (!clk) {
1587 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1588 return false;
1589 }
1590 } else tol = clk/8;
1591
1592 *foundclock = clk;
1593
1594 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1595 start = -1;
1596 for (i = 0; i < j - 4; ++i) {
1597 skip += tmpbuff[i];
b96bcc79 1598 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1599 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
1600 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
1601 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1602 start = i + 3;
1603 break;
1604 }
1605 }
1606 }
1607 }
1608 }
1609 // first ST not found - ERROR
1610 if (start < 0) {
1611 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1612 return false;
1613 }
b96bcc79 1614 if (waveLen[i+2] > clk*1+tol)
1615 phaseoff = 0;
1616 else
1617 phaseoff = clk/2;
1618
d1869c33 1619 // skip over the remainder of ST
1620 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1621
1622 // now do it again to find the end
1623 end = skip;
1624 for (i += 3; i < j - 4; ++i) {
1625 end += tmpbuff[i];
1626 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol) { //1 to 2 clocks depending on 2 bits prior
b96bcc79 1627 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
1628 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
1629 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1630 complete = true;
1631 break;
1632 }
1633 }
1634 }
1635 }
1636 }
b96bcc79 1637 end -= phaseoff;
d1869c33 1638 //didn't find second ST - ERROR
1639 if (!complete) {
1640 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1641 return false;
1642 }
b96bcc79 1643 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 1644 //now begin to trim out ST so we can use normal demod cmds
1645 start = skip;
1646 size_t datalen = end - start;
1647 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1648 if (datalen % clk > clk/8) {
1649 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1650 return false;
1651 } else {
1652 // padd the amount off - could be problematic... but shouldn't happen often
1653 datalen += datalen % clk;
1654 }
1655 // if datalen is less than one t55xx block - ERROR
1656 if (datalen/clk < 8*4) {
1657 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1658 return false;
1659 }
1660 size_t dataloc = start;
1661 size_t newloc = 0;
1662 i=0;
1663 // warning - overwriting buffer given with raw wave data with ST removed...
1664 while ( dataloc < bufsize-(clk/2) ) {
1665 //compensate for long high at end of ST not being high... (we cut out the high part)
1666 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1667 for(i=0; i < clk/2-tol; ++i) {
1668 buffer[dataloc+i] = high+5;
1669 }
1670 }
1671 for (i=0; i<datalen; ++i) {
1672 if (i+newloc < bufsize) {
1673 if (i+newloc < dataloc)
1674 buffer[i+newloc] = buffer[dataloc];
1675
1676 dataloc++;
1677 }
1678 }
1679 newloc += i;
1680 //skip next ST
1681 dataloc += clk*4;
1682 }
1683 *size = newloc;
1684 return true;
1685}
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