started to enable demod graphing
[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>
eb191de6 12#include "lfdemod.h"
d1869c33 13#include <string.h>
6fe5c94b 14
d1869c33 15//to allow debug print calls when used not on device
6fe5c94b 16void dummy(char *fmt, ...){}
17
18#ifndef ON_DEVICE
19#include "ui.h"
709665b5 20#include "cmdparser.h"
21#include "cmddata.h"
6fe5c94b 22#define prnt PrintAndLog
23#else
709665b5 24 uint8_t g_debugMode=0;
6fe5c94b 25#define prnt dummy
26#endif
6fe5c94b 27
a1d17964 28uint8_t justNoise(uint8_t *BitStream, size_t size)
29{
30 static const uint8_t THRESHOLD = 123;
31 //test samples are not just noise
32 uint8_t justNoise1 = 1;
33 for(size_t idx=0; idx < size && justNoise1 ;idx++){
34 justNoise1 = BitStream[idx] < THRESHOLD;
35 }
36 return justNoise1;
37}
38
1e090a61 39//by marshmellow
872e3d4d 40//get high and low values of a wave with passed in fuzz factor. also return noise test = 1 for passed or 0 for only noise
1e090a61 41int getHiLo(uint8_t *BitStream, size_t size, int *high, int *low, uint8_t fuzzHi, uint8_t fuzzLo)
42{
43 *high=0;
44 *low=255;
45 // get high and low thresholds
2eec55c8 46 for (size_t i=0; i < size; i++){
1e090a61 47 if (BitStream[i] > *high) *high = BitStream[i];
48 if (BitStream[i] < *low) *low = BitStream[i];
49 }
50 if (*high < 123) return -1; // just noise
75cbbe9a 51 *high = ((*high-128)*fuzzHi + 12800)/100;
52 *low = ((*low-128)*fuzzLo + 12800)/100;
1e090a61 53 return 1;
54}
55
a1d17964 56// by marshmellow
57// pass bits to be tested in bits, length bits passed in bitLen, and parity type (even=0 | odd=1) in pType
58// returns 1 if passed
59uint8_t parityTest(uint32_t bits, uint8_t bitLen, uint8_t pType)
60{
61 uint8_t ans = 0;
62 for (uint8_t i = 0; i < bitLen; i++){
63 ans ^= ((bits >> i) & 1);
64 }
e39a92bb 65 if (g_debugMode) prnt("DEBUG: ans: %d, ptype: %d, bits: %08X",ans,pType,bits);
a1d17964 66 return (ans == pType);
67}
68
709665b5 69// by marshmellow
70// takes a array of binary values, start position, length of bits per parity (includes parity bit),
88e85bde 71// Parity Type (1 for odd; 0 for even; 2 for Always 1's; 3 for Always 0's), and binary Length (length to run)
709665b5 72size_t removeParity(uint8_t *BitStream, size_t startIdx, uint8_t pLen, uint8_t pType, size_t bLen)
73{
74 uint32_t parityWd = 0;
75 size_t j = 0, bitCnt = 0;
e39a92bb 76 for (int word = 0; word < (bLen); word+=pLen) {
77 for (int bit=0; bit < pLen; bit++) {
709665b5 78 parityWd = (parityWd << 1) | BitStream[startIdx+word+bit];
79 BitStream[j++] = (BitStream[startIdx+word+bit]);
80 }
e88096ba 81 if (word+pLen > bLen) break;
e39a92bb 82
709665b5 83 j--; // overwrite parity with next data
84 // if parity fails then return 0
88e85bde 85 switch (pType) {
29435274 86 case 3: if (BitStream[j]==1) {return 0;} break; //should be 0 spacer bit
87 case 2: if (BitStream[j]==0) {return 0;} break; //should be 1 spacer bit
88 default: if (parityTest(parityWd, pLen, pType) == 0) {return 0;} break; //test parity
709665b5 89 }
90 bitCnt+=(pLen-1);
91 parityWd = 0;
92 }
93 // if we got here then all the parities passed
94 //return ID start index and size
95 return bitCnt;
96}
97
98// by marshmellow
99// takes a array of binary values, length of bits per parity (includes parity bit),
88e85bde 100// Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
101// Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
709665b5 102size_t addParity(uint8_t *BitSource, uint8_t *dest, uint8_t sourceLen, uint8_t pLen, uint8_t pType)
103{
104 uint32_t parityWd = 0;
105 size_t j = 0, bitCnt = 0;
106 for (int word = 0; word < sourceLen; word+=pLen-1) {
107 for (int bit=0; bit < pLen-1; bit++){
108 parityWd = (parityWd << 1) | BitSource[word+bit];
109 dest[j++] = (BitSource[word+bit]);
110 }
111 // if parity fails then return 0
88e85bde 112 switch (pType) {
113 case 3: dest[j++]=0; break; // marker bit which should be a 0
114 case 2: dest[j++]=1; break; // marker bit which should be a 1
115 default:
116 dest[j++] = parityTest(parityWd, pLen-1, pType) ^ 1;
117 break;
709665b5 118 }
119 bitCnt += pLen;
120 parityWd = 0;
121 }
122 // if we got here then all the parities passed
123 //return ID start index and size
124 return bitCnt;
125}
126
127uint32_t bytebits_to_byte(uint8_t *src, size_t numbits)
128{
129 uint32_t num = 0;
130 for(int i = 0 ; i < numbits ; i++)
131 {
132 num = (num << 1) | (*src);
133 src++;
134 }
135 return num;
136}
137
138//least significant bit first
139uint32_t bytebits_to_byteLSBF(uint8_t *src, size_t numbits)
140{
141 uint32_t num = 0;
142 for(int i = 0 ; i < numbits ; i++)
143 {
144 num = (num << 1) | *(src + (numbits-(i+1)));
145 }
146 return num;
147}
148
a1d17964 149//by marshmellow
2147c307 150//search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
a1d17964 151uint8_t preambleSearch(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx)
152{
e88096ba 153 return (preambleSearchEx(BitStream, preamble, pLen, size, startIdx, false)) ? 1 : 0;
154}
155
156// search for given preamble in given BitStream and return success=1 or fail=0 and startIndex (where it was found) and length if not fineone
157// fineone does not look for a repeating preamble for em4x05/4x69 sends preamble once, so look for it once in the first pLen bits
158bool preambleSearchEx(uint8_t *BitStream, uint8_t *preamble, size_t pLen, size_t *size, size_t *startIdx, bool findone) {
59f726c9 159 // Sanity check. If preamble length is bigger than bitstream length.
e88096ba 160 if ( *size <= pLen ) return false;
59f726c9 161
e88096ba 162 uint8_t foundCnt = 0;
163 for (size_t idx = 0; idx < *size - pLen; idx++) {
164 if (memcmp(BitStream+idx, preamble, pLen) == 0) {
e0165dcf 165 //first index found
166 foundCnt++;
e88096ba 167 if (foundCnt == 1) {
168 if (g_debugMode) prnt("DEBUG: preamble found at %u", idx);
e0165dcf 169 *startIdx = idx;
e88096ba 170 if (findone) return true;
171 } else if (foundCnt == 2) {
e0165dcf 172 *size = idx - *startIdx;
e88096ba 173 return true;
e0165dcf 174 }
175 }
176 }
4c6ccc2b 177 return false;
178}
179
34ff8985 180// find start of modulating data (for fsk and psk) in case of beginning noise or slow chip startup.
181size_t findModStart(uint8_t dest[], size_t size, uint8_t threshold_value, uint8_t expWaveSize) {
182 size_t i = 0;
183 size_t waveSizeCnt = 0;
184 uint8_t thresholdCnt = 0;
185 bool isAboveThreshold = dest[i++] >= threshold_value;
186 for (; i < size-20; i++ ) {
187 if(dest[i] < threshold_value && isAboveThreshold) {
188 thresholdCnt++;
189 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
190 isAboveThreshold = false;
191 waveSizeCnt = 0;
192 } else if (dest[i] >= threshold_value && !isAboveThreshold) {
193 thresholdCnt++;
194 if (thresholdCnt > 2 && waveSizeCnt < expWaveSize+1) break;
195 isAboveThreshold = true;
196 waveSizeCnt = 0;
197 } else {
198 waveSizeCnt++;
199 }
200 if (thresholdCnt > 10) break;
201 }
202 if (g_debugMode == 2) prnt("DEBUG: threshold Count reached at %u, count: %u",i, thresholdCnt);
203 return i;
204}
205
2147c307 206//by marshmellow
207//takes 1s and 0s and searches for EM410x format - output EM ID
208uint8_t Em410xDecode(uint8_t *BitStream, size_t *size, size_t *startIdx, uint32_t *hi, uint64_t *lo)
209{
e88096ba 210 //sanity checks
211 if (*size < 64) return 0;
2767fc02 212 if (BitStream[1]>1) return 0; //allow only 1s and 0s
213
e0165dcf 214 // 111111111 bit pattern represent start of frame
215 // include 0 in front to help get start pos
216 uint8_t preamble[] = {0,1,1,1,1,1,1,1,1,1};
e0165dcf 217 uint8_t errChk = 0;
e88096ba 218 uint8_t FmtLen = 10; // sets of 4 bits = end data
e0165dcf 219 *startIdx = 0;
220 errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, startIdx);
b1ee7eed 221 if ( errChk == 0 || (*size != 64 && *size != 128) ) return 0;
222 if (*size == 128) FmtLen = 22; // 22 sets of 4 bits
e88096ba 223
224 //skip last 4bit parity row for simplicity
225 *size = removeParity(BitStream, *startIdx + sizeof(preamble), 5, 0, FmtLen * 5);
226 if (*size == 40) { // std em410x format
227 *hi = 0;
228 *lo = ((uint64_t)(bytebits_to_byte(BitStream, 8)) << 32) | (bytebits_to_byte(BitStream + 8, 32));
229 } else if (*size == 88) { // long em format
230 *hi = (bytebits_to_byte(BitStream, 24));
231 *lo = ((uint64_t)(bytebits_to_byte(BitStream + 24, 32)) << 32) | (bytebits_to_byte(BitStream + 24 + 32, 32));
232 } else {
233 return 0;
e0165dcf 234 }
e88096ba 235 return 1;
2147c307 236}
237
fef74fdc 238//by marshmellow
239//demodulates strong heavily clipped samples
669959bc 240int cleanAskRawDemod(uint8_t *BinStream, size_t *size, int clk, int invert, int high, int low, int *startIdx)
23f0a7d8 241{
669959bc 242 *startIdx=0;
243 size_t bitCnt=0, smplCnt=1, errCnt=0;
244 bool waveHigh = (BinStream[0] >= high);
245 for (size_t i=1; i < *size; i++){
23f0a7d8 246 if (BinStream[i] >= high && waveHigh){
247 smplCnt++;
248 } else if (BinStream[i] <= low && !waveHigh){
249 smplCnt++;
250 } else { //transition
251 if ((BinStream[i] >= high && !waveHigh) || (BinStream[i] <= low && waveHigh)){
252 if (smplCnt > clk-(clk/4)-1) { //full clock
253 if (smplCnt > clk + (clk/4)+1) { //too many samples
254 errCnt++;
d1869c33 255 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
669959bc 256 BinStream[bitCnt++] = 7;
23f0a7d8 257 } else if (waveHigh) {
258 BinStream[bitCnt++] = invert;
259 BinStream[bitCnt++] = invert;
260 } else if (!waveHigh) {
261 BinStream[bitCnt++] = invert ^ 1;
262 BinStream[bitCnt++] = invert ^ 1;
263 }
669959bc 264 if (*startIdx==0) *startIdx = i-clk;
265 waveHigh = !waveHigh;
23f0a7d8 266 smplCnt = 0;
669959bc 267 } else if (smplCnt > (clk/2) - (clk/4)-1) { //half clock
23f0a7d8 268 if (waveHigh) {
269 BinStream[bitCnt++] = invert;
270 } else if (!waveHigh) {
271 BinStream[bitCnt++] = invert ^ 1;
272 }
669959bc 273 if (*startIdx==0) *startIdx = i-(clk/2);
274 waveHigh = !waveHigh;
23f0a7d8 275 smplCnt = 0;
23f0a7d8 276 } else {
277 smplCnt++;
278 //transition bit oops
279 }
280 } else { //haven't hit new high or new low yet
281 smplCnt++;
282 }
283 }
284 }
285 *size = bitCnt;
286 return errCnt;
287}
288
eb191de6 289//by marshmellow
fac69c3d 290//amplify based on ask edge detection
fef74fdc 291void askAmp(uint8_t *BitStream, size_t size)
292{
16ea2b8c 293 uint8_t Last = 128;
fef74fdc 294 for(size_t i = 1; i<size; i++){
295 if (BitStream[i]-BitStream[i-1]>=30) //large jump up
16ea2b8c 296 Last = 255;
297 else if(BitStream[i-1]-BitStream[i]>=20) //large jump down
298 Last = 0;
299
300 BitStream[i-1] = Last;
fef74fdc 301 }
302 return;
303}
01d0f8ae 304
fef74fdc 305//by marshmellow
306//attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
669959bc 307int askdemod_ext(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType, int *startIdx) {
fef74fdc 308 if (*size==0) return -1;
6e984446 309 int start = DetectASKClock(BinStream, *size, clk, maxErr); //clock default
2eec55c8 310 if (*clk==0 || start < 0) return -3;
fef74fdc 311 if (*invert != 1) *invert = 0;
312 if (amp==1) askAmp(BinStream, *size);
01d0f8ae 313 if (g_debugMode==2) prnt("DEBUG ASK: clk %d, beststart %d, amp %d", *clk, start, amp);
fef74fdc 314
669959bc 315 //start pos from detect ask clock is 1/2 clock offset
316 // NOTE: can be negative (demod assumes rest of wave was there)
317 *startIdx = start - (*clk/2);
2eec55c8 318 uint8_t initLoopMax = 255;
319 if (initLoopMax > *size) initLoopMax = *size;
ba1a299c 320 // Detect high and lows
fef74fdc 321 //25% clip in case highs and lows aren't clipped [marshmellow]
2eec55c8 322 int high, low;
fef74fdc 323 if (getHiLo(BinStream, initLoopMax, &high, &low, 75, 75) < 1)
324 return -2; //just noise
ba1a299c 325
fef74fdc 326 size_t errCnt = 0;
23f0a7d8 327 // if clean clipped waves detected run alternate demod
328 if (DetectCleanAskWave(BinStream, *size, high, low)) {
d1869c33 329 if (g_debugMode==2) prnt("DEBUG ASK: Clean Wave Detected - using clean wave demod");
669959bc 330 errCnt = cleanAskRawDemod(BinStream, size, *clk, *invert, high, low, startIdx);
331 if (askType) { //askman
332 uint8_t alignPos = 0;
333 errCnt = manrawdecode(BinStream, size, 0, &alignPos);
334 *startIdx += *clk/2 * alignPos;
335 if (g_debugMode) prnt("DEBUG ASK CLEAN: startIdx %i, alignPos %u", *startIdx, alignPos);
336 return errCnt;
337 } else { //askraw
fef74fdc 338 return errCnt;
669959bc 339 }
23f0a7d8 340 }
669959bc 341 if (g_debugMode) prnt("DEBUG ASK WEAK: startIdx %i", *startIdx);
d1869c33 342 if (g_debugMode==2) prnt("DEBUG ASK: Weak Wave Detected - using weak wave demod");
23f0a7d8 343
d1869c33 344 int lastBit; //set first clock check - can go negative
fef74fdc 345 size_t i, bitnum = 0; //output counter
346 uint8_t midBit = 0;
8b6abef5 347 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 348 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
349 size_t MaxBits = 3072; //max bits to collect
6e984446 350 lastBit = start - *clk;
fef74fdc 351
6e984446 352 for (i = start; i < *size; ++i) {
fef74fdc 353 if (i-lastBit >= *clk-tol){
354 if (BinStream[i] >= high) {
355 BinStream[bitnum++] = *invert;
356 } else if (BinStream[i] <= low) {
357 BinStream[bitnum++] = *invert ^ 1;
358 } else if (i-lastBit >= *clk+tol) {
359 if (bitnum > 0) {
d1869c33 360 if (g_debugMode==2) prnt("DEBUG ASK: Modulation Error at: %u", i);
fef74fdc 361 BinStream[bitnum++]=7;
362 errCnt++;
363 }
364 } else { //in tolerance - looking for peak
365 continue;
366 }
367 midBit = 0;
2eec55c8 368 lastBit += *clk;
fef74fdc 369 } else if (i-lastBit >= (*clk/2-tol) && !midBit && !askType){
370 if (BinStream[i] >= high) {
371 BinStream[bitnum++] = *invert;
372 } else if (BinStream[i] <= low) {
373 BinStream[bitnum++] = *invert ^ 1;
374 } else if (i-lastBit >= *clk/2+tol) {
375 BinStream[bitnum] = BinStream[bitnum-1];
376 bitnum++;
377 } else { //in tolerance - looking for peak
378 continue;
379 }
380 midBit = 1;
2eec55c8 381 }
382 if (bitnum >= MaxBits) break;
ba1a299c 383 }
2eec55c8 384 *size = bitnum;
6e984446 385 return errCnt;
eb191de6 386}
387
669959bc 388int askdemod(uint8_t *BinStream, size_t *size, int *clk, int *invert, int maxErr, uint8_t amp, uint8_t askType) {
389 int start = 0;
390 return askdemod_ext(BinStream, size, clk, invert, maxErr, amp, askType, &start);
391}
eb191de6 392//by marshmellow
393//take 10 and 01 and manchester decode
394//run through 2 times and take least errCnt
669959bc 395int manrawdecode(uint8_t * BitStream, size_t *size, uint8_t invert, uint8_t *alignPos)
eb191de6 396{
13d77ef9 397 uint16_t bitnum=0, MaxBits = 512, errCnt = 0;
398 size_t i, ii;
399 uint16_t bestErr = 1000, bestRun = 0;
fef74fdc 400 if (*size < 16) return -1;
2767fc02 401 //find correct start position [alignment]
13d77ef9 402 for (ii=0;ii<2;++ii){
fef74fdc 403 for (i=ii; i<*size-3; i+=2)
2eec55c8 404 if (BitStream[i]==BitStream[i+1])
ba1a299c 405 errCnt++;
2eec55c8 406
ba1a299c 407 if (bestErr>errCnt){
408 bestErr=errCnt;
409 bestRun=ii;
410 }
411 errCnt=0;
412 }
669959bc 413 *alignPos=bestRun;
2767fc02 414 //decode
fef74fdc 415 for (i=bestRun; i < *size-3; i+=2){
23f0a7d8 416 if(BitStream[i] == 1 && (BitStream[i+1] == 0)){
fef74fdc 417 BitStream[bitnum++]=invert;
23f0a7d8 418 } else if((BitStream[i] == 0) && BitStream[i+1] == 1){
fef74fdc 419 BitStream[bitnum++]=invert^1;
23f0a7d8 420 } else {
2767fc02 421 BitStream[bitnum++]=7;
ba1a299c 422 }
23f0a7d8 423 if(bitnum>MaxBits) break;
ba1a299c 424 }
23f0a7d8 425 *size=bitnum;
2eec55c8 426 return bestErr;
f822a063 427}
428
3606ac0a 429uint32_t manchesterEncode2Bytes(uint16_t datain) {
430 uint32_t output = 0;
431 uint8_t curBit = 0;
432 for (uint8_t i=0; i<16; i++) {
433 curBit = (datain >> (15-i) & 1);
434 output |= (1<<(((15-i)*2)+curBit));
435 }
436 return output;
437}
438
fef74fdc 439//by marshmellow
440//encode binary data into binary manchester
441int ManchesterEncode(uint8_t *BitStream, size_t size)
442{
443 size_t modIdx=20000, i=0;
444 if (size>modIdx) return -1;
445 for (size_t idx=0; idx < size; idx++){
446 BitStream[idx+modIdx++] = BitStream[idx];
447 BitStream[idx+modIdx++] = BitStream[idx]^1;
448 }
449 for (; i<(size*2); i++){
450 BitStream[i] = BitStream[i+20000];
451 }
452 return i;
453}
454
f822a063 455//by marshmellow
2147c307 456//take 01 or 10 = 1 and 11 or 00 = 0
457//check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
13d77ef9 458//decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
1e090a61 459int BiphaseRawDecode(uint8_t *BitStream, size_t *size, int offset, int invert)
f822a063 460{
2eec55c8 461 uint16_t bitnum = 0;
462 uint16_t errCnt = 0;
463 size_t i = offset;
2147c307 464 uint16_t MaxBits=512;
465 //if not enough samples - error
466 if (*size < 51) return -1;
467 //check for phase change faults - skip one sample if faulty
468 uint8_t offsetA = 1, offsetB = 1;
469 for (; i<48; i+=2){
470 if (BitStream[i+1]==BitStream[i+2]) offsetA=0;
471 if (BitStream[i+2]==BitStream[i+3]) offsetB=0;
472 }
473 if (!offsetA && offsetB) offset++;
474 for (i=offset; i<*size-3; i+=2){
475 //check for phase error
13d77ef9 476 if (BitStream[i+1]==BitStream[i+2]) {
2767fc02 477 BitStream[bitnum++]=7;
2147c307 478 errCnt++;
479 }
ba1a299c 480 if((BitStream[i]==1 && BitStream[i+1]==0) || (BitStream[i]==0 && BitStream[i+1]==1)){
1e090a61 481 BitStream[bitnum++]=1^invert;
ba1a299c 482 } else if((BitStream[i]==0 && BitStream[i+1]==0) || (BitStream[i]==1 && BitStream[i+1]==1)){
1e090a61 483 BitStream[bitnum++]=invert;
ba1a299c 484 } else {
2767fc02 485 BitStream[bitnum++]=7;
ba1a299c 486 errCnt++;
487 }
6de43508 488 if(bitnum>MaxBits) break;
ba1a299c 489 }
490 *size=bitnum;
491 return errCnt;
eb191de6 492}
493
fef74fdc 494// by marshmellow
11081e04 495// demod gProxIIDemod
496// error returns as -x
497// success returns start position in BitStream
498// BitStream must contain previously askrawdemod and biphasedemoded data
499int gProxII_Demod(uint8_t BitStream[], size_t *size)
500{
501 size_t startIdx=0;
502 uint8_t preamble[] = {1,1,1,1,1,0};
503
504 uint8_t errChk = preambleSearch(BitStream, preamble, sizeof(preamble), size, &startIdx);
505 if (errChk == 0) return -3; //preamble not found
506 if (*size != 96) return -2; //should have found 96 bits
507 //check first 6 spacer bits to verify format
508 if (!BitStream[startIdx+5] && !BitStream[startIdx+10] && !BitStream[startIdx+15] && !BitStream[startIdx+20] && !BitStream[startIdx+25] && !BitStream[startIdx+30]){
509 //confirmed proper separator bits found
510 //return start position
511 return (int) startIdx;
512 }
cf194819 513 return -5; //spacer bits not found - not a valid gproxII
11081e04 514}
515
cf194819 516//translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
669959bc 517size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow, int *startIdx)
eb191de6 518{
2eec55c8 519 size_t last_transition = 0;
520 size_t idx = 1;
ba1a299c 521 if (fchigh==0) fchigh=10;
522 if (fclow==0) fclow=8;
84871873 523 //set the threshold close to 0 (graph) or 128 std to avoid static
524 uint8_t threshold_value = 123;
f4eadf8a 525 size_t preLastSample = 0;
526 size_t LastSample = 0;
527 size_t currSample = 0;
c85858f5 528 if ( size < 1024 ) return 0; // not enough samples
529
34ff8985 530 //find start of modulating data in trace
531 idx = findModStart(dest, size, threshold_value, fchigh);
ba1a299c 532 // Need to threshold first sample
c85858f5 533 if(dest[idx] < threshold_value) dest[0] = 0;
ba1a299c 534 else dest[0] = 1;
c85858f5 535
669959bc 536 last_transition = idx;
537 idx++;
ba1a299c 538 size_t numBits = 0;
539 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
63744b56 540 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
ba1a299c 541 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
cf194819 542 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
669959bc 543 for(; idx < size; idx++) {
ba1a299c 544 // threshold current value
ba1a299c 545 if (dest[idx] < threshold_value) dest[idx] = 0;
546 else dest[idx] = 1;
547
548 // Check for 0->1 transition
cf194819 549 if (dest[idx-1] < dest[idx]) {
f4eadf8a 550 preLastSample = LastSample;
551 LastSample = currSample;
552 currSample = idx-last_transition;
cf194819 553 if (currSample < (fclow-2)) { //0-5 = garbage noise (or 0-3)
ba1a299c 554 //do nothing with extra garbage
cf194819 555 } else if (currSample < (fchigh-1)) { //6-8 = 8 sample waves (or 3-6 = 5)
556 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
669959bc 557 if (numBits > 1 && LastSample > (fchigh-2) && (preLastSample < (fchigh-1))){
cf194819 558 dest[numBits-1]=1;
f4eadf8a 559 }
2eec55c8 560 dest[numBits++]=1;
669959bc 561 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
c85858f5 562 } else if (currSample > (fchigh+1) && numBits < 3) { //12 + and first two bit = unusable garbage
563 //do nothing with beginning garbage and reset.. should be rare..
564 numBits = 0;
cf194819 565 } else if (currSample == (fclow+1) && LastSample == (fclow-1)) { // had a 7 then a 9 should be two 8's (or 4 then a 6 should be two 5's)
f4eadf8a 566 dest[numBits++]=1;
669959bc 567 if (numBits > 0 && *startIdx==0) *startIdx = idx - fclow;
cf194819 568 } else { //9+ = 10 sample waves (or 6+ = 7)
2eec55c8 569 dest[numBits++]=0;
669959bc 570 if (numBits > 0 && *startIdx==0) *startIdx = idx - fchigh;
ba1a299c 571 }
572 last_transition = idx;
ba1a299c 573 }
574 }
575 return numBits; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
eb191de6 576}
577
ba1a299c 578//translate 11111100000 to 10
cf194819 579//rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
2eec55c8 580size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen,
669959bc 581 uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx)
eb191de6 582{
ba1a299c 583 uint8_t lastval=dest[0];
2eec55c8 584 size_t idx=0;
ba1a299c 585 size_t numBits=0;
586 uint32_t n=1;
ba1a299c 587 for( idx=1; idx < size; idx++) {
13d77ef9 588 n++;
cf194819 589 if (dest[idx]==lastval) continue; //skip until we hit a transition
2eec55c8 590
669959bc 591 //find out how many bits (n) we collected (use 1/2 clk tolerance)
ba1a299c 592 //if lastval was 1, we have a 1->0 crossing
13d77ef9 593 if (dest[idx-1]==1) {
6fe5c94b 594 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 595 } else {// 0->1 crossing
75cbbe9a 596 n = (n * fchigh + rfLen/2) / rfLen;
ba1a299c 597 }
598 if (n == 0) n = 1;
669959bc 599
600 //first transition - save startidx
601 if (numBits == 0) {
602 if (lastval == 1) { //high to low
603 *startIdx += (fclow * idx) - (n*rfLen);
604 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fclow*idx %i, n*rflen %u", *startIdx, fclow*(idx), n*rfLen);
605 } else {
606 *startIdx += (fchigh * idx) - (n*rfLen);
607 if (g_debugMode==2) prnt("DEBUG FSK: startIdx %i, fchigh*idx %i, n*rflen %u", *startIdx, fchigh*(idx), n*rfLen);
608 }
609 }
ba1a299c 610
cf194819 611 //add to our destination the bits we collected
2eec55c8 612 memset(dest+numBits, dest[idx-1]^invert , n);
613 numBits += n;
ba1a299c 614 n=0;
615 lastval=dest[idx];
616 }//end for
13d77ef9 617 // if valid extra bits at the end were all the same frequency - add them in
75cbbe9a 618 if (n > rfLen/fchigh) {
13d77ef9 619 if (dest[idx-2]==1) {
75cbbe9a 620 n = (n * fclow + rfLen/2) / rfLen;
13d77ef9 621 } else {
75cbbe9a 622 n = (n * fchigh + rfLen/2) / rfLen;
13d77ef9 623 }
2eec55c8 624 memset(dest+numBits, dest[idx-1]^invert , n);
13d77ef9 625 numBits += n;
626 }
ba1a299c 627 return numBits;
eb191de6 628}
6fe5c94b 629
eb191de6 630//by marshmellow (from holiman's base)
631// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
669959bc 632int fskdemod_ext(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow, int *startIdx) {
ba1a299c 633 // FSK demodulator
669959bc 634 size = fsk_wave_demod(dest, size, fchigh, fclow, startIdx);
635 size = aggregate_bits(dest, size, rfLen, invert, fchigh, fclow, startIdx);
ba1a299c 636 return size;
eb191de6 637}
a1d17964 638
669959bc 639int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow) {
640 int startIdx=0;
641 return fskdemod_ext(dest, size, rfLen, invert, fchigh, fclow, &startIdx);
642}
643
eb191de6 644// loop to get raw HID waveform then FSK demodulate the TAG ID from it
ec75f5c1 645int HIDdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
eb191de6 646{
e0165dcf 647 if (justNoise(dest, *size)) return -1;
648
649 size_t numStart=0, size2=*size, startIdx=0;
650 // FSK demodulator
651 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
2eec55c8 652 if (*size < 96*2) return -2;
e0165dcf 653 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
654 uint8_t preamble[] = {0,0,0,1,1,1,0,1};
655 // find bitstring in array
656 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
657 if (errChk == 0) return -3; //preamble not found
658
659 numStart = startIdx + sizeof(preamble);
660 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
661 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
662 if (dest[idx] == dest[idx+1]){
663 return -4; //not manchester data
664 }
665 *hi2 = (*hi2<<1)|(*hi>>31);
666 *hi = (*hi<<1)|(*lo>>31);
667 //Then, shift in a 0 or one into low
668 if (dest[idx] && !dest[idx+1]) // 1 0
669 *lo=(*lo<<1)|1;
670 else // 0 1
671 *lo=(*lo<<1)|0;
672 }
673 return (int)startIdx;
eb191de6 674}
675
ec75f5c1 676// loop to get raw paradox waveform then FSK demodulate the TAG ID from it
a1d17964 677int ParadoxdemodFSK(uint8_t *dest, size_t *size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
ec75f5c1 678{
a1d17964 679 if (justNoise(dest, *size)) return -1;
680
681 size_t numStart=0, size2=*size, startIdx=0;
ec75f5c1 682 // FSK demodulator
a1d17964 683 *size = fskdemod(dest, size2,50,1,10,8); //fsk2a
684 if (*size < 96) return -2;
ec75f5c1 685
a1d17964 686 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
687 uint8_t preamble[] = {0,0,0,0,1,1,1,1};
688
689 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
690 if (errChk == 0) return -3; //preamble not found
691
692 numStart = startIdx + sizeof(preamble);
693 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
694 for (size_t idx = numStart; (idx-numStart) < *size - sizeof(preamble); idx+=2){
695 if (dest[idx] == dest[idx+1])
696 return -4; //not manchester data
697 *hi2 = (*hi2<<1)|(*hi>>31);
698 *hi = (*hi<<1)|(*lo>>31);
699 //Then, shift in a 0 or one into low
700 if (dest[idx] && !dest[idx+1]) // 1 0
701 *lo=(*lo<<1)|1;
702 else // 0 1
703 *lo=(*lo<<1)|0;
ec75f5c1 704 }
a1d17964 705 return (int)startIdx;
ec75f5c1 706}
707
eb191de6 708int IOdemodFSK(uint8_t *dest, size_t size)
709{
a1d17964 710 if (justNoise(dest, size)) return -1;
ba1a299c 711 //make sure buffer has data
a1d17964 712 if (size < 66*64) return -2;
ba1a299c 713 // FSK demodulator
a1d17964 714 size = fskdemod(dest, size, 64, 1, 10, 8); // FSK2a RF/64
715 if (size < 65) return -3; //did we get a good demod?
ba1a299c 716 //Index map
717 //0 10 20 30 40 50 60
718 //| | | | | | |
719 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
720 //-----------------------------------------------------------------------------
721 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
722 //
723 //XSF(version)facility:codeone+codetwo
724 //Handle the data
a1d17964 725 size_t startIdx = 0;
726 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,1};
727 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), &size, &startIdx);
728 if (errChk == 0) return -4; //preamble not found
eb191de6 729
a1d17964 730 if (!dest[startIdx+8] && dest[startIdx+17]==1 && dest[startIdx+26]==1 && dest[startIdx+35]==1 && dest[startIdx+44]==1 && dest[startIdx+53]==1){
731 //confirmed proper separator bits found
732 //return start position
733 return (int) startIdx;
1e090a61 734 }
a1d17964 735 return -5;
415274a7 736}
737
738// by marshmellow
739// find viking preamble 0xF200 in already demoded data
740int VikingDemod_AM(uint8_t *dest, size_t *size) {
415274a7 741 //make sure buffer has data
742 if (*size < 64*2) return -2;
743
744 size_t startIdx = 0;
745 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};
746 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
747 if (errChk == 0) return -4; //preamble not found
3ea7254a 748 uint32_t checkCalc = bytebits_to_byte(dest+startIdx,8) ^ bytebits_to_byte(dest+startIdx+8,8) ^ bytebits_to_byte(dest+startIdx+16,8)
749 ^ bytebits_to_byte(dest+startIdx+24,8) ^ bytebits_to_byte(dest+startIdx+32,8) ^ bytebits_to_byte(dest+startIdx+40,8)
750 ^ bytebits_to_byte(dest+startIdx+48,8) ^ bytebits_to_byte(dest+startIdx+56,8);
751 if ( checkCalc != 0xA8 ) return -5;
14331320 752 if (*size != 64) return -6;
415274a7 753 //return start position
754 return (int) startIdx;
1e090a61 755}
756
6923d3f1 757// find presco preamble 0x10D in already demoded data
758int PrescoDemod(uint8_t *dest, size_t *size) {
759 //make sure buffer has data
760 if (*size < 64*2) return -2;
761
762 size_t startIdx = 0;
763 uint8_t preamble[] = {1,0,0,0,0,1,1,0,1,0,0,0,0,0,0,0,0,0,0,0};
764 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
765 if (errChk == 0) return -4; //preamble not found
766 //return start position
767 return (int) startIdx;
768}
769
04bb0567 770// Ask/Biphase Demod then try to locate an ISO 11784/85 ID
771// BitStream must contain previously askrawdemod and biphasedemoded data
b2c330b3 772int FDXBdemodBI(uint8_t *dest, size_t *size)
04bb0567 773{
774 //make sure buffer has enough data
775 if (*size < 128) return -1;
776
777 size_t startIdx = 0;
778 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,1};
779
780 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
781 if (errChk == 0) return -2; //preamble not found
782 return (int)startIdx;
783}
784
1e090a61 785// by marshmellow
786// FSK Demod then try to locate an AWID ID
a1d17964 787int AWIDdemodFSK(uint8_t *dest, size_t *size)
1e090a61 788{
a1d17964 789 //make sure buffer has enough data
790 if (*size < 96*50) return -1;
791
792 if (justNoise(dest, *size)) return -2;
1e090a61 793
794 // FSK demodulator
a1d17964 795 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
796 if (*size < 96) return -3; //did we get a good demod?
797
798 uint8_t preamble[] = {0,0,0,0,0,0,0,1};
799 size_t startIdx = 0;
800 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
801 if (errChk == 0) return -4; //preamble not found
802 if (*size != 96) return -5;
803 return (int)startIdx;
1e090a61 804}
805
806// by marshmellow
6fe5c94b 807// FSK Demod then try to locate a Farpointe Data (pyramid) ID
a1d17964 808int PyramiddemodFSK(uint8_t *dest, size_t *size)
1e090a61 809{
f3bf15e4 810 //make sure buffer has data
811 if (*size < 128*50) return -5;
a1d17964 812
f3bf15e4 813 //test samples are not just noise
814 if (justNoise(dest, *size)) return -1;
1e090a61 815
f3bf15e4 816 // FSK demodulator
817 *size = fskdemod(dest, *size, 50, 1, 10, 8); // fsk2a RF/50
818 if (*size < 128) return -2; //did we get a good demod?
a1d17964 819
f3bf15e4 820 uint8_t preamble[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
a1d17964 821 size_t startIdx = 0;
822 uint8_t errChk = preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx);
823 if (errChk == 0) return -4; //preamble not found
824 if (*size != 128) return -3;
825 return (int)startIdx;
1e090a61 826}
827
fef74fdc 828// by marshmellow
829// to detect a wave that has heavily clipped (clean) samples
cc15a118 830uint8_t DetectCleanAskWave(uint8_t dest[], size_t size, uint8_t high, uint8_t low)
6de43508 831{
6fe5c94b 832 bool allArePeaks = true;
6de43508 833 uint16_t cntPeaks=0;
db829602 834 size_t loopEnd = 512+160;
1fbf8956 835 if (loopEnd > size) loopEnd = size;
db829602 836 for (size_t i=160; i<loopEnd; i++){
6de43508 837 if (dest[i]>low && dest[i]<high)
6fe5c94b 838 allArePeaks = false;
6de43508 839 else
840 cntPeaks++;
841 }
6fe5c94b 842 if (!allArePeaks){
843 if (cntPeaks > 300) return true;
6de43508 844 }
6fe5c94b 845 return allArePeaks;
6de43508 846}
2eec55c8 847// by marshmellow
848// to help detect clocks on heavily clipped samples
cc15a118 849// based on count of low to low
8b6abef5 850int DetectStrongAskClock(uint8_t dest[], size_t size, uint8_t high, uint8_t low, int *clock) {
cc15a118 851 uint8_t fndClk[] = {8,16,32,40,50,64,128};
852 size_t startwave;
db829602 853 size_t i = 100;
cc15a118 854 size_t minClk = 255;
8b6abef5 855 int shortestWaveIdx = 0;
cc15a118 856 // get to first full low to prime loop and skip incomplete first pulse
857 while ((dest[i] < high) && (i < size))
858 ++i;
859 while ((dest[i] > low) && (i < size))
860 ++i;
861
862 // loop through all samples
863 while (i < size) {
864 // measure from low to low
865 while ((dest[i] > low) && (i < size))
866 ++i;
8b6abef5 867 startwave = i;
cc15a118 868 while ((dest[i] < high) && (i < size))
869 ++i;
870 while ((dest[i] > low) && (i < size))
871 ++i;
872 //get minimum measured distance
8b6abef5 873 if (i-startwave < minClk && i < size) {
cc15a118 874 minClk = i - startwave;
8b6abef5 875 shortestWaveIdx = startwave;
876 }
13d77ef9 877 }
cc15a118 878 // set clock
709665b5 879 if (g_debugMode==2) prnt("DEBUG ASK: detectstrongASKclk smallest wave: %d",minClk);
cc15a118 880 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
8b6abef5 881 if (minClk >= fndClk[clkCnt]-(fndClk[clkCnt]/8) && minClk <= fndClk[clkCnt]+1) {
882 *clock = fndClk[clkCnt];
883 return shortestWaveIdx;
884 }
13d77ef9 885 }
cc15a118 886 return 0;
13d77ef9 887}
888
eb191de6 889// by marshmellow
890// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
891// maybe somehow adjust peak trimming value based on samples to fix?
6de43508 892// return start index of best starting position for that clock and return clock (by reference)
893int DetectASKClock(uint8_t dest[], size_t size, int *clock, int maxErr)
eb191de6 894{
6e984446 895 size_t i=1;
cc15a118 896 uint8_t clk[] = {255,8,16,32,40,50,64,100,128,255};
897 uint8_t clkEnd = 9;
2eec55c8 898 uint8_t loopCnt = 255; //don't need to loop through entire array...
db829602 899 if (size <= loopCnt+60) return -1; //not enough samples
900 size -= 60; //sometimes there is a strange end wave - filter out this....
6e984446 901 //if we already have a valid clock
902 uint8_t clockFnd=0;
cc15a118 903 for (;i<clkEnd;++i)
904 if (clk[i] == *clock) clockFnd = i;
6e984446 905 //clock found but continue to find best startpos
e0165dcf 906
907 //get high and low peak
908 int peak, low;
2eec55c8 909 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return -1;
e0165dcf 910
911 //test for large clean peaks
cc15a118 912 if (!clockFnd){
913 if (DetectCleanAskWave(dest, size, peak, low)==1){
8b6abef5 914 int ans = DetectStrongAskClock(dest, size, peak, low, clock);
915 if (g_debugMode==2) prnt("DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %i, ShortestWave: %i",clock, ans);
916 if (ans > 0) {
917 return ans; //return shortest wave start position
e0165dcf 918 }
919 }
920 }
2eec55c8 921 uint8_t ii;
922 uint8_t clkCnt, tol = 0;
923 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
924 uint8_t bestStart[]={0,0,0,0,0,0,0,0,0};
925 size_t errCnt = 0;
926 size_t arrLoc, loopEnd;
6e984446 927
cc15a118 928 if (clockFnd>0) {
929 clkCnt = clockFnd;
930 clkEnd = clockFnd+1;
931 }
932 else clkCnt=1;
933
934 //test each valid clock from smallest to greatest to see which lines up
935 for(; clkCnt < clkEnd; clkCnt++){
fef74fdc 936 if (clk[clkCnt] <= 32){
e0165dcf 937 tol=1;
938 }else{
939 tol=0;
940 }
2767fc02 941 //if no errors allowed - keep start within the first clock
cc15a118 942 if (!maxErr && size > clk[clkCnt]*2 + tol && clk[clkCnt]<128) loopCnt=clk[clkCnt]*2;
e0165dcf 943 bestErr[clkCnt]=1000;
6e984446 944 //try lining up the peaks by moving starting point (try first few clocks)
cc15a118 945 for (ii=0; ii < loopCnt; ii++){
2eec55c8 946 if (dest[ii] < peak && dest[ii] > low) continue;
947
948 errCnt=0;
949 // now that we have the first one lined up test rest of wave array
950 loopEnd = ((size-ii-tol) / clk[clkCnt]) - 1;
951 for (i=0; i < loopEnd; ++i){
952 arrLoc = ii + (i * clk[clkCnt]);
953 if (dest[arrLoc] >= peak || dest[arrLoc] <= low){
954 }else if (dest[arrLoc-tol] >= peak || dest[arrLoc-tol] <= low){
955 }else if (dest[arrLoc+tol] >= peak || dest[arrLoc+tol] <= low){
956 }else{ //error no peak detected
957 errCnt++;
e0165dcf 958 }
959 }
cc15a118 960 //if we found no errors then we can stop here and a low clock (common clocks)
2eec55c8 961 // this is correct one - return this clock
709665b5 962 if (g_debugMode == 2) prnt("DEBUG ASK: clk %d, err %d, startpos %d, endpos %d",clk[clkCnt],errCnt,ii,i);
cc15a118 963 if(errCnt==0 && clkCnt<7) {
964 if (!clockFnd) *clock = clk[clkCnt];
2eec55c8 965 return ii;
966 }
967 //if we found errors see if it is lowest so far and save it as best run
968 if(errCnt<bestErr[clkCnt]){
969 bestErr[clkCnt]=errCnt;
970 bestStart[clkCnt]=ii;
971 }
e0165dcf 972 }
973 }
cc15a118 974 uint8_t iii;
e0165dcf 975 uint8_t best=0;
cc15a118 976 for (iii=1; iii<clkEnd; ++iii){
2eec55c8 977 if (bestErr[iii] < bestErr[best]){
978 if (bestErr[iii] == 0) bestErr[iii]=1;
e0165dcf 979 // current best bit to error ratio vs new bit to error ratio
2eec55c8 980 if ( (size/clk[best])/bestErr[best] < (size/clk[iii])/bestErr[iii] ){
e0165dcf 981 best = iii;
982 }
983 }
709665b5 984 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 985 }
cc15a118 986 if (!clockFnd) *clock = clk[best];
e0165dcf 987 return bestStart[best];
eb191de6 988}
ba1a299c 989
990//by marshmellow
6de43508 991//detect psk clock by reading each phase shift
992// a phase shift is determined by measuring the sample length of each wave
8b6abef5 993int DetectPSKClock_ext(uint8_t dest[], size_t size, int clock, int *firstPhaseShift) {
e0165dcf 994 uint8_t clk[]={255,16,32,40,50,64,100,128,255}; //255 is not a valid clock
995 uint16_t loopCnt = 4096; //don't need to loop through entire array...
996 if (size == 0) return 0;
db829602 997 if (size<loopCnt) loopCnt = size-20;
e0165dcf 998
999 //if we already have a valid clock quit
1000 size_t i=1;
1001 for (; i < 8; ++i)
1002 if (clk[i] == clock) return clock;
1003
1004 size_t waveStart=0, waveEnd=0, firstFullWave=0, lastClkBit=0;
1005 uint8_t clkCnt, fc=0, fullWaveLen=0, tol=1;
1006 uint16_t peakcnt=0, errCnt=0, waveLenCnt=0;
1007 uint16_t bestErr[]={1000,1000,1000,1000,1000,1000,1000,1000,1000};
1008 uint16_t peaksdet[]={0,0,0,0,0,0,0,0,0};
2eec55c8 1009 fc = countFC(dest, size, 0);
1010 if (fc!=2 && fc!=4 && fc!=8) return -1;
709665b5 1011 if (g_debugMode==2) prnt("DEBUG PSK: FC: %d",fc);
e0165dcf 1012
1013 //find first full wave
db829602 1014 for (i=160; i<loopCnt; i++){
e0165dcf 1015 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1016 if (waveStart == 0) {
1017 waveStart = i+1;
db829602 1018 //prnt("DEBUG: waveStart: %d",waveStart);
e0165dcf 1019 } else {
1020 waveEnd = i+1;
db829602 1021 //prnt("DEBUG: waveEnd: %d",waveEnd);
e0165dcf 1022 waveLenCnt = waveEnd-waveStart;
1023 if (waveLenCnt > fc){
1024 firstFullWave = waveStart;
1025 fullWaveLen=waveLenCnt;
1026 break;
1027 }
1028 waveStart=0;
1029 }
1030 }
1031 }
8b6abef5 1032 *firstPhaseShift = firstFullWave;
709665b5 1033 if (g_debugMode ==2) prnt("DEBUG PSK: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
e0165dcf 1034 //test each valid clock from greatest to smallest to see which lines up
1035 for(clkCnt=7; clkCnt >= 1 ; clkCnt--){
1036 lastClkBit = firstFullWave; //set end of wave as clock align
1037 waveStart = 0;
1038 errCnt=0;
1039 peakcnt=0;
709665b5 1040 if (g_debugMode == 2) prnt("DEBUG PSK: clk: %d, lastClkBit: %d",clk[clkCnt],lastClkBit);
e0165dcf 1041
1042 for (i = firstFullWave+fullWaveLen-1; i < loopCnt-2; i++){
1043 //top edge of wave = start of new wave
1044 if (dest[i] < dest[i+1] && dest[i+1] >= dest[i+2]){
1045 if (waveStart == 0) {
1046 waveStart = i+1;
1047 waveLenCnt=0;
1048 } else { //waveEnd
1049 waveEnd = i+1;
1050 waveLenCnt = waveEnd-waveStart;
1051 if (waveLenCnt > fc){
1052 //if this wave is a phase shift
709665b5 1053 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 1054 if (i+1 >= lastClkBit + clk[clkCnt] - tol){ //should be a clock bit
1055 peakcnt++;
1056 lastClkBit+=clk[clkCnt];
1057 } else if (i<lastClkBit+8){
1058 //noise after a phase shift - ignore
1059 } else { //phase shift before supposed to based on clock
1060 errCnt++;
1061 }
1062 } else if (i+1 > lastClkBit + clk[clkCnt] + tol + fc){
1063 lastClkBit+=clk[clkCnt]; //no phase shift but clock bit
1064 }
1065 waveStart=i+1;
1066 }
1067 }
1068 }
1069 if (errCnt == 0){
1070 return clk[clkCnt];
1071 }
1072 if (errCnt <= bestErr[clkCnt]) bestErr[clkCnt]=errCnt;
1073 if (peakcnt > peaksdet[clkCnt]) peaksdet[clkCnt]=peakcnt;
1074 }
1075 //all tested with errors
1076 //return the highest clk with the most peaks found
1077 uint8_t best=7;
1078 for (i=7; i>=1; i--){
1079 if (peaksdet[i] > peaksdet[best]) {
1080 best = i;
1081 }
709665b5 1082 if (g_debugMode == 2) prnt("DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d",clk[i],peaksdet[i],bestErr[i],clk[best]);
e0165dcf 1083 }
1084 return clk[best];
ba1a299c 1085}
1086
669959bc 1087int DetectPSKClock(uint8_t dest[], size_t size, int clock) {
1088 int firstPhaseShift = 0;
1089 return DetectPSKClock_ext(dest, size, clock, &firstPhaseShift);
1090}
1091
db829602 1092int DetectStrongNRZClk(uint8_t *dest, size_t size, int peak, int low){
1093 //find shortest transition from high to low
1094 size_t i = 0;
1095 size_t transition1 = 0;
1096 int lowestTransition = 255;
6fe5c94b 1097 bool lastWasHigh = false;
1098
1099 //find first valid beginning of a high or low wave
1100 while ((dest[i] >= peak || dest[i] <= low) && (i < size))
1101 ++i;
1102 while ((dest[i] < peak && dest[i] > low) && (i < size))
1103 ++i;
1104 lastWasHigh = (dest[i] >= peak);
1105
db829602 1106 if (i==size) return 0;
1107 transition1 = i;
1108
1109 for (;i < size; i++) {
1110 if ((dest[i] >= peak && !lastWasHigh) || (dest[i] <= low && lastWasHigh)) {
1111 lastWasHigh = (dest[i] >= peak);
1112 if (i-transition1 < lowestTransition) lowestTransition = i-transition1;
1113 transition1 = i;
1114 }
1115 }
1116 if (lowestTransition == 255) lowestTransition = 0;
709665b5 1117 if (g_debugMode==2) prnt("DEBUG NRZ: detectstrongNRZclk smallest wave: %d",lowestTransition);
db829602 1118 return lowestTransition;
1119}
1120
6de43508 1121//by marshmellow
1122//detect nrz clock by reading #peaks vs no peaks(or errors)
8b6abef5 1123int DetectNRZClock_ext(uint8_t dest[], size_t size, int clock, size_t *clockStartIdx) {
2eec55c8 1124 size_t i=0;
1125 uint8_t clk[]={8,16,32,40,50,64,100,128,255};
1126 size_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1127 if (size == 0) return 0;
db829602 1128 if (size<loopCnt) loopCnt = size-20;
e0165dcf 1129 //if we already have a valid clock quit
1130 for (; i < 8; ++i)
1131 if (clk[i] == clock) return clock;
1132
1133 //get high and low peak
1134 int peak, low;
2eec55c8 1135 if (getHiLo(dest, loopCnt, &peak, &low, 75, 75) < 1) return 0;
e0165dcf 1136
db829602 1137 int lowestTransition = DetectStrongNRZClk(dest, size-20, peak, low);
2eec55c8 1138 size_t ii;
e0165dcf 1139 uint8_t clkCnt;
1140 uint8_t tol = 0;
db829602 1141 uint16_t smplCnt = 0;
1142 int16_t peakcnt = 0;
1143 int16_t peaksdet[] = {0,0,0,0,0,0,0,0};
1144 uint16_t maxPeak = 255;
6fe5c94b 1145 bool firstpeak = false;
e0165dcf 1146 //test for large clipped waves
1147 for (i=0; i<loopCnt; i++){
1148 if (dest[i] >= peak || dest[i] <= low){
db829602 1149 if (!firstpeak) continue;
1150 smplCnt++;
e0165dcf 1151 } else {
6fe5c94b 1152 firstpeak=true;
db829602 1153 if (smplCnt > 6 ){
1154 if (maxPeak > smplCnt){
1155 maxPeak = smplCnt;
1156 //prnt("maxPk: %d",maxPeak);
1157 }
1158 peakcnt++;
1159 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1160 smplCnt=0;
e0165dcf 1161 }
e0165dcf 1162 }
1163 }
6fe5c94b 1164 bool errBitHigh = 0;
1165 bool bitHigh = 0;
1166 uint8_t ignoreCnt = 0;
1167 uint8_t ignoreWindow = 4;
1168 bool lastPeakHigh = 0;
1169 int lastBit = 0;
8b6abef5 1170 size_t bestStart[]={0,0,0,0,0,0,0,0,0};
e0165dcf 1171 peakcnt=0;
1172 //test each valid clock from smallest to greatest to see which lines up
1173 for(clkCnt=0; clkCnt < 8; ++clkCnt){
db829602 1174 //ignore clocks smaller than smallest peak
1175 if (clk[clkCnt] < maxPeak - (clk[clkCnt]/4)) continue;
e0165dcf 1176 //try lining up the peaks by moving starting point (try first 256)
db829602 1177 for (ii=20; ii < loopCnt; ++ii){
e0165dcf 1178 if ((dest[ii] >= peak) || (dest[ii] <= low)){
6fe5c94b 1179 peakcnt = 0;
1180 bitHigh = false;
1181 ignoreCnt = 0;
1182 lastBit = ii-clk[clkCnt];
db829602 1183 //loop through to see if this start location works
1184 for (i = ii; i < size-20; ++i) {
6fe5c94b 1185 //if we are at a clock bit
db829602 1186 if ((i >= lastBit + clk[clkCnt] - tol) && (i <= lastBit + clk[clkCnt] + tol)) {
1187 //test high/low
1188 if (dest[i] >= peak || dest[i] <= low) {
6fe5c94b 1189 //if same peak don't count it
1190 if ((dest[i] >= peak && !lastPeakHigh) || (dest[i] <= low && lastPeakHigh)) {
1191 peakcnt++;
1192 }
1193 lastPeakHigh = (dest[i] >= peak);
1194 bitHigh = true;
1195 errBitHigh = false;
db829602 1196 ignoreCnt = ignoreWindow;
1197 lastBit += clk[clkCnt];
db829602 1198 } else if (i == lastBit + clk[clkCnt] + tol) {
1199 lastBit += clk[clkCnt];
db829602 1200 }
1201 //else if not a clock bit and no peaks
1202 } else if (dest[i] < peak && dest[i] > low){
db829602 1203 if (ignoreCnt==0){
6fe5c94b 1204 bitHigh=false;
1205 if (errBitHigh==true) peakcnt--;
1206 errBitHigh=false;
db829602 1207 } else {
1208 ignoreCnt--;
1209 }
1210 // else if not a clock bit but we have a peak
6fe5c94b 1211 } else if ((dest[i]>=peak || dest[i]<=low) && (!bitHigh)) {
db829602 1212 //error bar found no clock...
6fe5c94b 1213 errBitHigh=true;
e0165dcf 1214 }
1215 }
1216 if(peakcnt>peaksdet[clkCnt]) {
8b6abef5 1217 bestStart[clkCnt]=ii;
e0165dcf 1218 peaksdet[clkCnt]=peakcnt;
1219 }
1220 }
1221 }
1222 }
1223 int iii=7;
2eec55c8 1224 uint8_t best=0;
e0165dcf 1225 for (iii=7; iii > 0; iii--){
6fe5c94b 1226 if ((peaksdet[iii] >= (peaksdet[best]-1)) && (peaksdet[iii] <= peaksdet[best]+1) && lowestTransition) {
1227 if (clk[iii] > (lowestTransition - (clk[iii]/8)) && clk[iii] < (lowestTransition + (clk[iii]/8))) {
db829602 1228 best = iii;
1229 }
6fe5c94b 1230 } else if (peaksdet[iii] > peaksdet[best]){
1231 best = iii;
e0165dcf 1232 }
709665b5 1233 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 1234 }
8b6abef5 1235 *clockStartIdx = bestStart[best];
e0165dcf 1236 return clk[best];
ba1a299c 1237}
1238
669959bc 1239int DetectNRZClock(uint8_t dest[], size_t size, int clock) {
1240 size_t bestStart=0;
1241 return DetectNRZClock_ext(dest, size, clock, &bestStart);
1242}
1243
04d2721b 1244// by marshmellow
1245// convert psk1 demod to psk2 demod
1246// only transition waves are 1s
1247void psk1TOpsk2(uint8_t *BitStream, size_t size)
1248{
1249 size_t i=1;
1250 uint8_t lastBit=BitStream[0];
1251 for (; i<size; i++){
2767fc02 1252 if (BitStream[i]==7){
7a8a982b 1253 //ignore errors
1254 } else if (lastBit!=BitStream[i]){
04d2721b 1255 lastBit=BitStream[i];
1256 BitStream[i]=1;
1257 } else {
1258 BitStream[i]=0;
1259 }
1260 }
1261 return;
1262}
ba1a299c 1263
3bc66a96 1264// by marshmellow
1265// convert psk2 demod to psk1 demod
1266// from only transition waves are 1s to phase shifts change bit
1267void psk2TOpsk1(uint8_t *BitStream, size_t size)
1268{
712ebfa6 1269 uint8_t phase=0;
1270 for (size_t i=0; i<size; i++){
1271 if (BitStream[i]==1){
3bc66a96 1272 phase ^=1;
1273 }
1274 BitStream[i]=phase;
1275 }
1276 return;
1277}
1278
04d2721b 1279// redesigned by marshmellow adjusted from existing decode functions
1280// indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
ba1a299c 1281int indala26decode(uint8_t *bitStream, size_t *size, uint8_t *invert)
1282{
1283 //26 bit 40134 format (don't know other formats)
14331320 1284 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};
1285 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};
1286 size_t startidx = 0;
1287 if (!preambleSearch(bitStream, preamble, sizeof(preamble), size, &startidx)){
1288 // if didn't find preamble try again inverting
1289 if (!preambleSearch(bitStream, preamble_i, sizeof(preamble_i), size, &startidx)) return -1;
1290 *invert ^= 1;
1291 }
1292 if (*size != 64 && *size != 224) return -2;
1293 if (*invert==1)
1294 for (size_t i = startidx; i < *size; i++)
1295 bitStream[i] ^= 1;
ba1a299c 1296
14331320 1297 return (int) startidx;
ba1a299c 1298}
1299
d1869c33 1300// by marshmellow - demodulate NRZ wave - requires a read with strong signal
04d2721b 1301// peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
669959bc 1302int nrzRawDemod_ext(uint8_t *dest, size_t *size, int *clk, int *invert, int *startIdx) {
e0165dcf 1303 if (justNoise(dest, *size)) return -1;
1304 *clk = DetectNRZClock(dest, *size, *clk);
1305 if (*clk==0) return -2;
2eec55c8 1306 size_t i, gLen = 4096;
db829602 1307 if (gLen>*size) gLen = *size-20;
e0165dcf 1308 int high, low;
1309 if (getHiLo(dest, gLen, &high, &low, 75, 75) < 1) return -3; //25% fuzz on high 25% fuzz on low
db829602 1310
1311 uint8_t bit=0;
1312 //convert wave samples to 1's and 0's
1313 for(i=20; i < *size-20; i++){
1314 if (dest[i] >= high) bit = 1;
1315 if (dest[i] <= low) bit = 0;
1316 dest[i] = bit;
e0165dcf 1317 }
db829602 1318 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1319 size_t lastBit = 0;
1320 size_t numBits = 0;
1321 for(i=21; i < *size-20; i++) {
1322 //if transition detected or large number of same bits - store the passed bits
1323 if (dest[i] != dest[i-1] || (i-lastBit) == (10 * *clk)) {
1324 memset(dest+numBits, dest[i-1] ^ *invert, (i - lastBit + (*clk/4)) / *clk);
1325 numBits += (i - lastBit + (*clk/4)) / *clk;
669959bc 1326 if (lastBit == 0) {
1327 *startIdx = i - (numBits * *clk);
1328 if (g_debugMode==2) prnt("DEBUG NRZ: startIdx %i", *startIdx);
1329 }
db829602 1330 lastBit = i-1;
e0165dcf 1331 }
e0165dcf 1332 }
db829602 1333 *size = numBits;
1334 return 0;
ba1a299c 1335}
669959bc 1336int nrzRawDemod(uint8_t *dest, size_t *size, int *clk, int *invert) {
1337 int startIdx = 0;
1338 return nrzRawDemod_ext(dest, size, clk, invert, &startIdx);
8b6abef5 1339}
1340
1e090a61 1341//by marshmellow
03e6bb4a 1342//detects the bit clock for FSK given the high and low Field Clocks
8b6abef5 1343uint8_t detectFSKClk_ext(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow, int *firstClockEdge) {
e0165dcf 1344 uint8_t clk[] = {8,16,32,40,50,64,100,128,0};
1345 uint16_t rfLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1346 uint8_t rfCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1347 uint8_t rfLensFnd = 0;
2eec55c8 1348 uint8_t lastFCcnt = 0;
1349 uint16_t fcCounter = 0;
e0165dcf 1350 uint16_t rfCounter = 0;
1351 uint8_t firstBitFnd = 0;
1352 size_t i;
1353 if (size == 0) return 0;
1354
6fe5c94b 1355 uint8_t fcTol = ((fcHigh*100 - fcLow*100)/2 + 50)/100; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
e0165dcf 1356 rfLensFnd=0;
1357 fcCounter=0;
1358 rfCounter=0;
1359 firstBitFnd=0;
1360 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
6fe5c94b 1361 // prime i to first peak / up transition
1362 for (i = 160; i < size-20; i++)
e0165dcf 1363 if (BitStream[i] > BitStream[i-1] && BitStream[i]>=BitStream[i+1])
1364 break;
1365
6fe5c94b 1366 for (; i < size-20; i++){
2eec55c8 1367 fcCounter++;
1368 rfCounter++;
1369
1370 if (BitStream[i] <= BitStream[i-1] || BitStream[i] < BitStream[i+1])
1371 continue;
1372 // else new peak
1373 // if we got less than the small fc + tolerance then set it to the small fc
33a1fe96 1374 // if it is inbetween set it to the last counter
1375 if (fcCounter < fcHigh && fcCounter > fcLow)
1376 fcCounter = lastFCcnt;
1377 else if (fcCounter < fcLow+fcTol)
2eec55c8 1378 fcCounter = fcLow;
1379 else //set it to the large fc
1380 fcCounter = fcHigh;
1381
1382 //look for bit clock (rf/xx)
1383 if ((fcCounter < lastFCcnt || fcCounter > lastFCcnt)){
1384 //not the same size as the last wave - start of new bit sequence
1385 if (firstBitFnd > 1){ //skip first wave change - probably not a complete bit
1386 for (int ii=0; ii<15; ii++){
6fe5c94b 1387 if (rfLens[ii] >= (rfCounter-4) && rfLens[ii] <= (rfCounter+4)){
2eec55c8 1388 rfCnts[ii]++;
1389 rfCounter = 0;
1390 break;
e0165dcf 1391 }
e0165dcf 1392 }
2eec55c8 1393 if (rfCounter > 0 && rfLensFnd < 15){
1394 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1395 rfCnts[rfLensFnd]++;
1396 rfLens[rfLensFnd++] = rfCounter;
1397 }
1398 } else {
8b6abef5 1399 *firstClockEdge = i;
2eec55c8 1400 firstBitFnd++;
e0165dcf 1401 }
2eec55c8 1402 rfCounter=0;
1403 lastFCcnt=fcCounter;
e0165dcf 1404 }
2eec55c8 1405 fcCounter=0;
e0165dcf 1406 }
1407 uint8_t rfHighest=15, rfHighest2=15, rfHighest3=15;
1408
1409 for (i=0; i<15; i++){
e0165dcf 1410 //get highest 2 RF values (might need to get more values to compare or compare all?)
1411 if (rfCnts[i]>rfCnts[rfHighest]){
1412 rfHighest3=rfHighest2;
1413 rfHighest2=rfHighest;
1414 rfHighest=i;
1415 } else if(rfCnts[i]>rfCnts[rfHighest2]){
1416 rfHighest3=rfHighest2;
1417 rfHighest2=i;
1418 } else if(rfCnts[i]>rfCnts[rfHighest3]){
1419 rfHighest3=i;
1420 }
709665b5 1421 if (g_debugMode==2) prnt("DEBUG FSK: RF %d, cnts %d",rfLens[i], rfCnts[i]);
e0165dcf 1422 }
1423 // set allowed clock remainder tolerance to be 1 large field clock length+1
1424 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1425 uint8_t tol1 = fcHigh+1;
1426
709665b5 1427 if (g_debugMode==2) prnt("DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d",rfLens[rfHighest],rfLens[rfHighest2],rfLens[rfHighest3]);
e0165dcf 1428
1429 // loop to find the highest clock that has a remainder less than the tolerance
1430 // compare samples counted divided by
6fe5c94b 1431 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
e0165dcf 1432 int ii=7;
6fe5c94b 1433 for (; ii>=2; ii--){
e0165dcf 1434 if (rfLens[rfHighest] % clk[ii] < tol1 || rfLens[rfHighest] % clk[ii] > clk[ii]-tol1){
1435 if (rfLens[rfHighest2] % clk[ii] < tol1 || rfLens[rfHighest2] % clk[ii] > clk[ii]-tol1){
1436 if (rfLens[rfHighest3] % clk[ii] < tol1 || rfLens[rfHighest3] % clk[ii] > clk[ii]-tol1){
709665b5 1437 if (g_debugMode==2) prnt("DEBUG FSK: clk %d divides into the 3 most rf values within tolerance",clk[ii]);
e0165dcf 1438 break;
1439 }
1440 }
1441 }
1442 }
1443
33a1fe96 1444 if (ii<2) return 0; // oops we went too far
e0165dcf 1445
1446 return clk[ii];
03e6bb4a 1447}
1e090a61 1448
669959bc 1449uint8_t detectFSKClk(uint8_t *BitStream, size_t size, uint8_t fcHigh, uint8_t fcLow) {
1450 int firstClockEdge = 0;
1451 return detectFSKClk_ext(BitStream, size, fcHigh, fcLow, &firstClockEdge);
1452}
1453
03e6bb4a 1454//by marshmellow
1455//countFC is to detect the field clock lengths.
1456//counts and returns the 2 most common wave lengths
6de43508 1457//mainly used for FSK field clock detection
2eec55c8 1458uint16_t countFC(uint8_t *BitStream, size_t size, uint8_t fskAdj)
03e6bb4a 1459{
6fe5c94b 1460 uint8_t fcLens[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
1461 uint16_t fcCnts[] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
e0165dcf 1462 uint8_t fcLensFnd = 0;
2d99d991 1463 uint8_t lastFCcnt = 0;
2eec55c8 1464 uint8_t fcCounter = 0;
e0165dcf 1465 size_t i;
2d99d991 1466 if (size < 180) return 0;
e0165dcf 1467
1468 // prime i to first up transition
6fe5c94b 1469 for (i = 160; i < size-20; i++)
e0165dcf 1470 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1])
1471 break;
1472
6fe5c94b 1473 for (; i < size-20; i++){
e0165dcf 1474 if (BitStream[i] > BitStream[i-1] && BitStream[i] >= BitStream[i+1]){
1475 // new up transition
1476 fcCounter++;
2eec55c8 1477 if (fskAdj){
1478 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1479 if (lastFCcnt==5 && fcCounter==9) fcCounter--;
1480 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1481 if ((fcCounter==9) || fcCounter==4) fcCounter++;
e0165dcf 1482 // save last field clock count (fc/xx)
2eec55c8 1483 lastFCcnt = fcCounter;
1484 }
e0165dcf 1485 // find which fcLens to save it to:
6fe5c94b 1486 for (int ii=0; ii<15; ii++){
e0165dcf 1487 if (fcLens[ii]==fcCounter){
1488 fcCnts[ii]++;
1489 fcCounter=0;
1490 break;
1491 }
1492 }
6fe5c94b 1493 if (fcCounter>0 && fcLensFnd<15){
e0165dcf 1494 //add new fc length
1495 fcCnts[fcLensFnd]++;
1496 fcLens[fcLensFnd++]=fcCounter;
1497 }
1498 fcCounter=0;
1499 } else {
1500 // count sample
1501 fcCounter++;
1502 }
1503 }
1504
6fe5c94b 1505 uint8_t best1=14, best2=14, best3=14;
e0165dcf 1506 uint16_t maxCnt1=0;
1507 // go through fclens and find which ones are bigest 2
6fe5c94b 1508 for (i=0; i<15; i++){
e0165dcf 1509 // get the 3 best FC values
1510 if (fcCnts[i]>maxCnt1) {
1511 best3=best2;
1512 best2=best1;
1513 maxCnt1=fcCnts[i];
1514 best1=i;
1515 } else if(fcCnts[i]>fcCnts[best2]){
1516 best3=best2;
1517 best2=i;
1518 } else if(fcCnts[i]>fcCnts[best3]){
1519 best3=i;
1520 }
709665b5 1521 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 1522 }
6fe5c94b 1523 if (fcLens[best1]==0) return 0;
e0165dcf 1524 uint8_t fcH=0, fcL=0;
1525 if (fcLens[best1]>fcLens[best2]){
1526 fcH=fcLens[best1];
1527 fcL=fcLens[best2];
1528 } else{
1529 fcH=fcLens[best2];
1530 fcL=fcLens[best1];
1531 }
709665b5 1532 if ((size-180)/fcH/3 > fcCnts[best1]+fcCnts[best2]) {
1533 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]);
1534 return 0; //lots of waves not psk or fsk
1535 }
e0165dcf 1536 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1537
1538 uint16_t fcs = (((uint16_t)fcH)<<8) | fcL;
2eec55c8 1539 if (fskAdj) return fcs;
1540 return fcLens[best1];
6de43508 1541}
1542
1543//by marshmellow - demodulate PSK1 wave
1544//uses wave lengths (# Samples)
669959bc 1545int pskRawDemod_ext(uint8_t dest[], size_t *size, int *clock, int *invert, int *startIdx) {
e0165dcf 1546 if (size == 0) return -1;
2eec55c8 1547 uint16_t loopCnt = 4096; //don't need to loop through entire array...
e0165dcf 1548 if (*size<loopCnt) loopCnt = *size;
1549
db829602 1550 size_t numBits=0;
e0165dcf 1551 uint8_t curPhase = *invert;
6980d66b 1552 size_t i=0, waveStart=1, waveEnd=0, firstFullWave=0, lastClkBit=0;
34ff8985 1553 uint16_t fc=0, fullWaveLen=0, tol=1;
1554 uint16_t errCnt=0, waveLenCnt=0, errCnt2=0;
1555 fc = countFC(dest, *size, 1);
1556 uint8_t fc2 = fc >> 8;
1557 if (fc2 == 10) return -1; //fsk found - quit
1558 fc = fc & 0xFF;
e0165dcf 1559 if (fc!=2 && fc!=4 && fc!=8) return -1;
1560 //PrintAndLog("DEBUG: FC: %d",fc);
1561 *clock = DetectPSKClock(dest, *size, *clock);
2eec55c8 1562 if (*clock == 0) return -1;
6980d66b 1563
34ff8985 1564 //find start of modulating data in trace
1565 uint8_t threshold_value = 123; //-5
1566 i = findModStart(dest, *size, threshold_value, fc);
6980d66b 1567
e0165dcf 1568 //find first phase shift
34ff8985 1569 int avgWaveVal=0, lastAvgWaveVal=0;
1570 waveStart = i;
1571 for (; i<loopCnt; i++) {
1572 // find peak
e0165dcf 1573 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1574 waveEnd = i+1;
6980d66b 1575 if (g_debugMode == 2) prnt("DEBUG PSK: waveEnd: %u, waveStart: %u",waveEnd, waveStart);
e0165dcf 1576 waveLenCnt = waveEnd-waveStart;
6980d66b 1577 if (waveLenCnt > fc && waveStart > fc && !(waveLenCnt > fc+3)){ //not first peak and is a large wave but not out of whack
e0165dcf 1578 lastAvgWaveVal = avgWaveVal/(waveLenCnt);
1579 firstFullWave = waveStart;
1580 fullWaveLen=waveLenCnt;
34ff8985 1581 //if average wave value is > graph 0 then it is an up wave or a 1 (could cause inverting)
1582 if (lastAvgWaveVal > threshold_value) curPhase ^= 1;
e0165dcf 1583 break;
669959bc 1584 }
1585
e0165dcf 1586 waveStart = i+1;
1587 avgWaveVal = 0;
1588 }
2eec55c8 1589 avgWaveVal += dest[i+2];
e0165dcf 1590 }
db829602 1591 if (firstFullWave == 0) {
1592 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1593 // so skip a little to ensure we are past any Start Signal
1594 firstFullWave = 160;
1595 memset(dest, curPhase, firstFullWave / *clock);
1596 } else {
1597 memset(dest, curPhase^1, firstFullWave / *clock);
1598 }
1599 //advance bits
1600 numBits += (firstFullWave / *clock);
669959bc 1601 *startIdx = firstFullWave - (*clock * numBits)+2;
db829602 1602 //set start of wave as clock align
1603 lastClkBit = firstFullWave;
669959bc 1604 if (g_debugMode==2) prnt("DEBUG PSK: firstFullWave: %u, waveLen: %u, startIdx %i",firstFullWave,fullWaveLen, *startIdx);
34ff8985 1605 if (g_debugMode==2) prnt("DEBUG PSK: clk: %d, lastClkBit: %u, fc: %u", *clock, lastClkBit,(unsigned int) fc);
e0165dcf 1606 waveStart = 0;
e0165dcf 1607 dest[numBits++] = curPhase; //set first read bit
2eec55c8 1608 for (i = firstFullWave + fullWaveLen - 1; i < *size-3; i++){
e0165dcf 1609 //top edge of wave = start of new wave
1610 if (dest[i]+fc < dest[i+1] && dest[i+1] >= dest[i+2]){
1611 if (waveStart == 0) {
1612 waveStart = i+1;
2eec55c8 1613 waveLenCnt = 0;
e0165dcf 1614 avgWaveVal = dest[i+1];
1615 } else { //waveEnd
1616 waveEnd = i+1;
1617 waveLenCnt = waveEnd-waveStart;
1618 lastAvgWaveVal = avgWaveVal/waveLenCnt;
669959bc 1619 if (waveLenCnt > fc){
e0165dcf 1620 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
2eec55c8 1621 //this wave is a phase shift
e0165dcf 1622 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1623 if (i+1 >= lastClkBit + *clock - tol){ //should be a clock bit
2eec55c8 1624 curPhase ^= 1;
e0165dcf 1625 dest[numBits++] = curPhase;
1626 lastClkBit += *clock;
2eec55c8 1627 } else if (i < lastClkBit+10+fc){
e0165dcf 1628 //noise after a phase shift - ignore
1629 } else { //phase shift before supposed to based on clock
1630 errCnt++;
2767fc02 1631 dest[numBits++] = 7;
e0165dcf 1632 }
1633 } else if (i+1 > lastClkBit + *clock + tol + fc){
1634 lastClkBit += *clock; //no phase shift but clock bit
1635 dest[numBits++] = curPhase;
34ff8985 1636 } else if (waveLenCnt < fc - 1) { //wave is smaller than field clock (shouldn't happen often)
1637 errCnt2++;
1638 if(errCnt2 > 101) return errCnt2;
e0165dcf 1639 }
2eec55c8 1640 avgWaveVal = 0;
1641 waveStart = i+1;
e0165dcf 1642 }
1643 }
2eec55c8 1644 avgWaveVal += dest[i+1];
e0165dcf 1645 }
1646 *size = numBits;
1647 return errCnt;
6de43508 1648}
d1869c33 1649
669959bc 1650int pskRawDemod(uint8_t dest[], size_t *size, int *clock, int *invert) {
1651 int startIdx = 0;
1652 return pskRawDemod_ext(dest, size, clock, invert, &startIdx);
ab812dfa 1653}
1654
d1869c33 1655//by marshmellow
1656//attempt to identify a Sequence Terminator in ASK modulated raw wave
ab812dfa 1657bool DetectST_ext(uint8_t buffer[], size_t *size, int *foundclock, size_t *ststart, size_t *stend) {
d1869c33 1658 size_t bufsize = *size;
1659 //need to loop through all samples and identify our clock, look for the ST pattern
1660 uint8_t fndClk[] = {8,16,32,40,50,64,128};
1661 int clk = 0;
1662 int tol = 0;
b96bcc79 1663 int i, j, skip, start, end, low, high, minClk, waveStart;
d1869c33 1664 bool complete = false;
01d0f8ae 1665 int tmpbuff[bufsize / 32]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1666 int waveLen[bufsize / 32]; // if clock is larger then we waste memory in array size that is not needed...
d1869c33 1667 size_t testsize = (bufsize < 512) ? bufsize : 512;
b96bcc79 1668 int phaseoff = 0;
d1869c33 1669 high = low = 128;
1670 memset(tmpbuff, 0, sizeof(tmpbuff));
1671
1672 if ( getHiLo(buffer, testsize, &high, &low, 80, 80) == -1 ) {
1673 if (g_debugMode==2) prnt("DEBUG STT: just noise detected - quitting");
1674 return false; //just noise
1675 }
d1869c33 1676 i = 0;
1677 j = 0;
1678 minClk = 255;
1679 // get to first full low to prime loop and skip incomplete first pulse
1680 while ((buffer[i] < high) && (i < bufsize))
1681 ++i;
1682 while ((buffer[i] > low) && (i < bufsize))
1683 ++i;
1684 skip = i;
1685
1686 // populate tmpbuff buffer with pulse lengths
1687 while (i < bufsize) {
1688 // measure from low to low
1689 while ((buffer[i] > low) && (i < bufsize))
1690 ++i;
1691 start= i;
1692 while ((buffer[i] < high) && (i < bufsize))
1693 ++i;
b96bcc79 1694 //first high point for this wave
1695 waveStart = i;
d1869c33 1696 while ((buffer[i] > low) && (i < bufsize))
1697 ++i;
01d0f8ae 1698 if (j >= (bufsize/32)) {
d1869c33 1699 break;
1700 }
b96bcc79 1701 waveLen[j] = i - waveStart; //first high to first low
d1869c33 1702 tmpbuff[j++] = i - start;
1703 if (i-start < minClk && i < bufsize) {
1704 minClk = i - start;
1705 }
1706 }
1707 // set clock - might be able to get this externally and remove this work...
1708 if (!clk) {
1709 for (uint8_t clkCnt = 0; clkCnt<7; clkCnt++) {
1710 tol = fndClk[clkCnt]/8;
1711 if (minClk >= fndClk[clkCnt]-tol && minClk <= fndClk[clkCnt]+1) {
1712 clk=fndClk[clkCnt];
1713 break;
1714 }
1715 }
1716 // clock not found - ERROR
1717 if (!clk) {
1718 if (g_debugMode==2) prnt("DEBUG STT: clock not found - quitting");
1719 return false;
1720 }
1721 } else tol = clk/8;
1722
1723 *foundclock = clk;
1724
1725 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1726 start = -1;
1727 for (i = 0; i < j - 4; ++i) {
1728 skip += tmpbuff[i];
b96bcc79 1729 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
1730 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
1731 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
1732 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1733 start = i + 3;
1734 break;
1735 }
1736 }
1737 }
1738 }
1739 }
1740 // first ST not found - ERROR
1741 if (start < 0) {
1742 if (g_debugMode==2) prnt("DEBUG STT: first STT not found - quitting");
1743 return false;
01d0f8ae 1744 } else {
1745 if (g_debugMode==2) prnt("DEBUG STT: first STT found at: %d, j=%d",start, j);
d1869c33 1746 }
b96bcc79 1747 if (waveLen[i+2] > clk*1+tol)
1748 phaseoff = 0;
1749 else
1750 phaseoff = clk/2;
1751
d1869c33 1752 // skip over the remainder of ST
1753 skip += clk*7/2; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1754
1755 // now do it again to find the end
1756 end = skip;
1757 for (i += 3; i < j - 4; ++i) {
1758 end += tmpbuff[i];
01d0f8ae 1759 if (tmpbuff[i] >= clk*1-tol && tmpbuff[i] <= (clk*2)+tol && waveLen[i] < clk+tol) { //1 to 2 clocks depending on 2 bits prior
b96bcc79 1760 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
1761 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
1762 if (tmpbuff[i+3] >= clk*1-tol && tmpbuff[i+3] <= clk*2+tol) { //1 to 2 clocks for end of ST + first bit
d1869c33 1763 complete = true;
1764 break;
1765 }
1766 }
1767 }
1768 }
1769 }
b96bcc79 1770 end -= phaseoff;
d1869c33 1771 //didn't find second ST - ERROR
1772 if (!complete) {
1773 if (g_debugMode==2) prnt("DEBUG STT: second STT not found - quitting");
1774 return false;
1775 }
b96bcc79 1776 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 1777 //now begin to trim out ST so we can use normal demod cmds
1778 start = skip;
1779 size_t datalen = end - start;
1780 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
01d0f8ae 1781 if ( clk - (datalen % clk) <= clk/8) {
1782 // padd the amount off - could be problematic... but shouldn't happen often
1783 datalen += clk - (datalen % clk);
1784 } else if ( (datalen % clk) <= clk/8 ) {
1785 // padd the amount off - could be problematic... but shouldn't happen often
1786 datalen -= datalen % clk;
1787 } else {
d1869c33 1788 if (g_debugMode==2) prnt("DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting", datalen, clk, datalen % clk);
1789 return false;
d1869c33 1790 }
1791 // if datalen is less than one t55xx block - ERROR
1792 if (datalen/clk < 8*4) {
1793 if (g_debugMode==2) prnt("DEBUG STT: datalen is less than 1 full t55xx block - quitting");
1794 return false;
1795 }
1796 size_t dataloc = start;
01d0f8ae 1797 if (buffer[dataloc-(clk*4)-(clk/8)] <= low && buffer[dataloc] <= low && buffer[dataloc-(clk*4)] >= high) {
1798 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1799 for ( i=0; i <= (clk/8); ++i ) {
1800 if ( buffer[dataloc - (clk*4) - i] <= low ) {
1801 dataloc -= i;
1802 break;
1803 }
1804 }
1805 }
1806
d1869c33 1807 size_t newloc = 0;
1808 i=0;
01d0f8ae 1809 if (g_debugMode==2) prnt("DEBUG STT: Starting STT trim - start: %d, datalen: %d ",dataloc, datalen);
ab812dfa 1810 bool firstrun = true;
d1869c33 1811 // warning - overwriting buffer given with raw wave data with ST removed...
1812 while ( dataloc < bufsize-(clk/2) ) {
cf194819 1813 //compensate for long high at end of ST not being high due to signal loss... (and we cut out the start of wave high part)
d1869c33 1814 if (buffer[dataloc]<high && buffer[dataloc]>low && buffer[dataloc+3]<high && buffer[dataloc+3]>low) {
1815 for(i=0; i < clk/2-tol; ++i) {
1816 buffer[dataloc+i] = high+5;
1817 }
dda5a928 1818 } //test for single sample outlier (high between two lows) in the case of very strong waves
1819 if (buffer[dataloc] >= high && buffer[dataloc+2] <= low) {
1820 buffer[dataloc] = buffer[dataloc+2];
1821 buffer[dataloc+1] = buffer[dataloc+2];
d1869c33 1822 }
ab812dfa 1823 if (firstrun) {
f75b313b 1824 *stend = dataloc;
1825 *ststart = dataloc-(clk*4);
ab812dfa 1826 firstrun=false;
1827 }
d1869c33 1828 for (i=0; i<datalen; ++i) {
1829 if (i+newloc < bufsize) {
1830 if (i+newloc < dataloc)
1831 buffer[i+newloc] = buffer[dataloc];
1832
01d0f8ae 1833 dataloc++;
d1869c33 1834 }
1835 }
1836 newloc += i;
cf194819 1837 //skip next ST - we just assume it will be there from now on...
01d0f8ae 1838 if (g_debugMode==2) prnt("DEBUG STT: skipping STT at %d to %d", dataloc, dataloc+(clk*4));
d1869c33 1839 dataloc += clk*4;
1840 }
1841 *size = newloc;
1842 return true;
1843}
8b6abef5 1844
669959bc 1845bool DetectST(uint8_t buffer[], size_t *size, int *foundclock) {
1846 size_t ststart = 0, stend = 0;
1847 return DetectST_ext(buffer, size, foundclock, &ststart, &stend);
1848}
1849
8b6abef5 1850// by iceman
1851// find Visa2000 preamble in already demoded data
1852int Visa2kDemod_AM(uint8_t *dest, size_t *size) {
1853 if (*size < 96) return -1; //make sure buffer has data
1854 size_t startIdx = 0;
1855 uint8_t preamble[] = {0,1,0,1,0,1,1,0,0,1,0,0,1,0,0,1,0,1,0,1,0,0,1,1,0,0,1,1,0,0,1,0};
1856 if (preambleSearch(dest, preamble, sizeof(preamble), size, &startIdx) == 0)
1857 return -2; //preamble not found
1858 if (*size != 96) return -3; //wrong demoded size
1859 //return start position
1860 return (int)startIdx;
1861}
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