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cvs.zerfleddert.de Git - proxmark3-svn/blob - common/lfdemod.c
8b31f1a4c10a751cd447d2667aa89f7a57a7e22e
1 //-----------------------------------------------------------------------------
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
7 //-----------------------------------------------------------------------------
8 // Low frequency demod/decode commands
9 //-----------------------------------------------------------------------------
15 //un_comment to allow debug print calls when used not on device
16 void dummy ( char * fmt
, ...){}
20 #include "cmdparser.h"
22 #define prnt PrintAndLog
24 uint8_t g_debugMode
= 0 ;
28 uint8_t justNoise ( uint8_t * BitStream
, size_t size
)
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
;
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
41 int getHiLo ( uint8_t * BitStream
, size_t size
, int * high
, int * low
, uint8_t fuzzHi
, uint8_t fuzzLo
)
45 // get high and low thresholds
46 for ( size_t i
= 0 ; i
< size
; i
++){
47 if ( BitStream
[ i
] > * high
) * high
= BitStream
[ i
];
48 if ( BitStream
[ i
] < * low
) * low
= BitStream
[ i
];
50 if (* high
< 123 ) return - 1 ; // just noise
51 * high
= ((* high
- 128 )* fuzzHi
+ 12800 )/ 100 ;
52 * low
= ((* low
- 128 )* fuzzLo
+ 12800 )/ 100 ;
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
59 uint8_t parityTest ( uint32_t bits
, uint8_t bitLen
, uint8_t pType
)
62 for ( uint8_t i
= 0 ; i
< bitLen
; i
++){
63 ans
^= (( bits
>> i
) & 1 );
65 //PrintAndLog("DEBUG: ans: %d, ptype: %d",ans,pType);
66 return ( ans
== pType
);
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 for Always 1's; 3 for Always 0's), and binary Length (length to run)
72 size_t removeParity ( uint8_t * BitStream
, size_t startIdx
, uint8_t pLen
, uint8_t pType
, size_t bLen
)
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
]);
81 j
--; // overwrite parity with next data
82 // if parity fails then return 0
84 case 3 : if ( BitStream
[ j
]== 1 ) return 0 ; break ; //should be 0 spacer bit
85 case 2 : if ( BitStream
[ j
]== 0 ) return 0 ; break ; //should be 1 spacer bit
86 default : //test parity
87 if ( parityTest ( parityWd
, pLen
, pType
) == 0 ) return 0 ; break ;
92 // if we got here then all the parities passed
93 //return ID start index and size
98 // takes a array of binary values, length of bits per parity (includes parity bit),
99 // Parity Type (1 for odd; 0 for even; 2 Always 1's; 3 Always 0's), and binary Length (length to run)
100 // Make sure *dest is long enough to store original sourceLen + #_of_parities_to_be_added
101 size_t addParity ( uint8_t * BitSource
, uint8_t * dest
, uint8_t sourceLen
, uint8_t pLen
, uint8_t pType
)
103 uint32_t parityWd
= 0 ;
104 size_t j
= 0 , bitCnt
= 0 ;
105 for ( int word
= 0 ; word
< sourceLen
; word
+= pLen
- 1 ) {
106 for ( int bit
= 0 ; bit
< pLen
- 1 ; bit
++){
107 parityWd
= ( parityWd
<< 1 ) | BitSource
[ word
+ bit
];
108 dest
[ j
++] = ( BitSource
[ word
+ bit
]);
111 // if parity fails then return 0
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
116 dest
[ j
++] = parityTest ( parityWd
, pLen
- 1 , pType
) ^ 1 ;
122 // if we got here then all the parities passed
123 //return ID start index and size
127 uint32_t bytebits_to_byte ( uint8_t * src
, size_t numbits
)
130 for ( int i
= 0 ; i
< numbits
; i
++) {
131 num
= ( num
<< 1 ) | (* src
);
137 //least significant bit first
138 uint32_t bytebits_to_byteLSBF ( uint8_t * src
, size_t numbits
)
141 for ( int i
= 0 ; i
< numbits
; i
++) {
142 num
= ( num
<< 1 ) | *( src
+ ( numbits
-( i
+ 1 )));
148 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
149 uint8_t preambleSearch ( uint8_t * BitStream
, uint8_t * preamble
, size_t pLen
, size_t * size
, size_t * startIdx
)
152 for ( int idx
= 0 ; idx
< * size
- pLen
; idx
++){
153 if ( memcmp ( BitStream
+ idx
, preamble
, pLen
) == 0 ){
160 * size
= idx
- * startIdx
;
169 //takes 1s and 0s and searches for EM410x format - output EM ID
170 uint8_t Em410xDecode ( uint8_t * BitStream
, size_t * size
, size_t * startIdx
, uint32_t * hi
, uint64_t * lo
)
172 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
173 // otherwise could be a void with no arguments
176 if ( BitStream
[ 1 ]> 1 ) return 0 ; //allow only 1s and 0s
178 // 111111111 bit pattern represent start of frame
179 // include 0 in front to help get start pos
180 uint8_t preamble
[] = { 0 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 };
182 uint32_t parityBits
= 0 ;
186 errChk
= preambleSearch ( BitStream
, preamble
, sizeof ( preamble
), size
, startIdx
);
187 if ( errChk
== 0 || * size
< 64 ) return 0 ;
188 if (* size
> 64 ) FmtLen
= 22 ;
189 * startIdx
+= 1 ; //get rid of 0 from preamble
191 for ( i
= 0 ; i
< FmtLen
; i
++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
192 parityBits
= bytebits_to_byte ( BitStream
+( i
* 5 )+ idx
, 5 );
193 //check even parity - quit if failed
194 if ( parityTest ( parityBits
, 5 , 0 ) == 0 ) return 0 ;
195 //set uint64 with ID from BitStream
196 for ( uint8_t ii
= 0 ; ii
< 4 ; ii
++){
197 * hi
= (* hi
<< 1 ) | (* lo
>> 63 );
198 * lo
= (* lo
<< 1 ) | ( BitStream
[( i
* 5 )+ ii
+ idx
]);
201 if ( errChk
!= 0 ) return 1 ;
202 //skip last 5 bit parity test for simplicity.
208 //demodulates strong heavily clipped samples
209 int cleanAskRawDemod ( uint8_t * BinStream
, size_t * size
, int clk
, int invert
, int high
, int low
)
211 size_t bitCnt
= 0 , smplCnt
= 0 , errCnt
= 0 ;
212 uint8_t waveHigh
= 0 ;
213 for ( size_t i
= 0 ; i
< * size
; i
++){
214 if ( BinStream
[ i
] >= high
&& waveHigh
){
216 } else if ( BinStream
[ i
] <= low
&& ! waveHigh
){
218 } else { //transition
219 if (( BinStream
[ i
] >= high
&& ! waveHigh
) || ( BinStream
[ i
] <= low
&& waveHigh
)){
220 if ( smplCnt
> clk
-( clk
/ 4 )- 1 ) { //full clock
221 if ( smplCnt
> clk
+ ( clk
/ 4 )+ 1 ) { //too many samples
223 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Modulation Error at: %u" , i
);
224 BinStream
[ bitCnt
++]= 7 ;
225 } else if ( waveHigh
) {
226 BinStream
[ bitCnt
++] = invert
;
227 BinStream
[ bitCnt
++] = invert
;
228 } else if (! waveHigh
) {
229 BinStream
[ bitCnt
++] = invert
^ 1 ;
230 BinStream
[ bitCnt
++] = invert
^ 1 ;
234 } else if ( smplCnt
> ( clk
/ 2 ) - ( clk
/ 4 )- 1 ) {
236 BinStream
[ bitCnt
++] = invert
;
237 } else if (! waveHigh
) {
238 BinStream
[ bitCnt
++] = invert
^ 1 ;
242 } else if (! bitCnt
) {
244 waveHigh
= ( BinStream
[ i
] >= high
);
248 //transition bit oops
250 } else { //haven't hit new high or new low yet
260 void askAmp ( uint8_t * BitStream
, size_t size
)
263 for ( size_t i
= 1 ; i
< size
; ++ i
){
264 if ( BitStream
[ i
]- BitStream
[ i
- 1 ] >= 30 ) //large jump up
266 else if ( BitStream
[ i
- 1 ] - BitStream
[ i
] >= 20 ) //large jump down
274 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
275 int askdemod ( uint8_t * BinStream
, size_t * size
, int * clk
, int * invert
, int maxErr
, uint8_t amp
, uint8_t askType
)
277 if (* size
== 0 ) return - 1 ;
278 int start
= DetectASKClock ( BinStream
, * size
, clk
, maxErr
); //clock default
279 if (* clk
== 0 || start
< 0 ) return - 3 ;
280 if (* invert
!= 1 ) * invert
= 0 ;
281 if ( amp
== 1 ) askAmp ( BinStream
, * size
);
282 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: clk %d, beststart %d" , * clk
, start
);
284 uint8_t initLoopMax
= 255 ;
285 if ( initLoopMax
> * size
) initLoopMax
= * size
;
286 // Detect high and lows
287 //25% clip in case highs and lows aren't clipped [marshmellow]
289 if ( getHiLo ( BinStream
, initLoopMax
, & high
, & low
, 75 , 75 ) < 1 )
290 return - 2 ; //just noise
293 // if clean clipped waves detected run alternate demod
294 if ( DetectCleanAskWave ( BinStream
, * size
, high
, low
)) {
295 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Clean Wave Detected - using clean wave demod" );
296 errCnt
= cleanAskRawDemod ( BinStream
, size
, * clk
, * invert
, high
, low
);
297 if ( askType
) //askman
298 return manrawdecode ( BinStream
, size
, 0 );
302 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Weak Wave Detected - using weak wave demod" );
304 int lastBit
; //set first clock check - can go negative
305 size_t i
, bitnum
= 0 ; //output counter
307 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
308 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
309 size_t MaxBits
= 3072 ; //max bits to collect
310 lastBit
= start
- * clk
;
312 for ( i
= start
; i
< * size
; ++ i
) {
313 if ( i
- lastBit
>= * clk
- tol
){
314 if ( BinStream
[ i
] >= high
) {
315 BinStream
[ bitnum
++] = * invert
;
316 } else if ( BinStream
[ i
] <= low
) {
317 BinStream
[ bitnum
++] = * invert
^ 1 ;
318 } else if ( i
- lastBit
>= * clk
+ tol
) {
320 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Modulation Error at: %u" , i
);
321 BinStream
[ bitnum
++]= 7 ;
324 } else { //in tolerance - looking for peak
329 } else if ( i
- lastBit
>= (* clk
/ 2 - tol
) && ! midBit
&& ! askType
){
330 if ( BinStream
[ i
] >= high
) {
331 BinStream
[ bitnum
++] = * invert
;
332 } else if ( BinStream
[ i
] <= low
) {
333 BinStream
[ bitnum
++] = * invert
^ 1 ;
334 } else if ( i
- lastBit
>= * clk
/ 2 + tol
) {
335 BinStream
[ bitnum
] = BinStream
[ bitnum
- 1 ];
337 } else { //in tolerance - looking for peak
342 if ( bitnum
>= MaxBits
) break ;
349 //take 10 and 01 and manchester decode
350 //run through 2 times and take least errCnt
351 int manrawdecode ( uint8_t * BitStream
, size_t * size
, uint8_t invert
)
353 uint16_t bitnum
= 0 , MaxBits
= 512 , errCnt
= 0 ;
355 uint16_t bestErr
= 1000 , bestRun
= 0 ;
356 if (* size
< 16 ) return - 1 ;
357 //find correct start position [alignment]
358 for ( ii
= 0 ; ii
< 2 ;++ ii
){
359 for ( i
= ii
; i
<* size
- 3 ; i
+= 2 )
360 if ( BitStream
[ i
]== BitStream
[ i
+ 1 ])
370 for ( i
= bestRun
; i
< * size
- 3 ; i
+= 2 ){
371 if ( BitStream
[ i
] == 1 && ( BitStream
[ i
+ 1 ] == 0 )){
372 BitStream
[ bitnum
++]= invert
;
373 } else if (( BitStream
[ i
] == 0 ) && BitStream
[ i
+ 1 ] == 1 ){
374 BitStream
[ bitnum
++]= invert
^ 1 ;
376 BitStream
[ bitnum
++]= 7 ;
378 if ( bitnum
> MaxBits
) break ;
384 uint32_t manchesterEncode2Bytes ( uint16_t datain
) {
387 for ( uint8_t i
= 0 ; i
< 16 ; i
++) {
388 curBit
= ( datain
>> ( 15 - i
) & 1 );
389 output
|= ( 1 <<((( 15 - i
)* 2 )+ curBit
));
395 //encode binary data into binary manchester
396 int ManchesterEncode ( uint8_t * BitStream
, size_t size
)
398 size_t modIdx
= 20000 , i
= 0 ;
399 if ( size
> modIdx
) return - 1 ;
400 for ( size_t idx
= 0 ; idx
< size
; idx
++){
401 BitStream
[ idx
+ modIdx
++] = BitStream
[ idx
];
402 BitStream
[ idx
+ modIdx
++] = BitStream
[ idx
]^ 1 ;
404 for (; i
<( size
* 2 ); i
++){
405 BitStream
[ i
] = BitStream
[ i
+ 20000 ];
411 //take 01 or 10 = 1 and 11 or 00 = 0
412 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
413 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
414 int BiphaseRawDecode ( uint8_t * BitStream
, size_t * size
, int offset
, int invert
)
419 uint16_t MaxBits
= 512 ;
420 //if not enough samples - error
421 if (* size
< 51 ) return - 1 ;
422 //check for phase change faults - skip one sample if faulty
423 uint8_t offsetA
= 1 , offsetB
= 1 ;
425 if ( BitStream
[ i
+ 1 ]== BitStream
[ i
+ 2 ]) offsetA
= 0 ;
426 if ( BitStream
[ i
+ 2 ]== BitStream
[ i
+ 3 ]) offsetB
= 0 ;
428 if (! offsetA
&& offsetB
) offset
++;
429 for ( i
= offset
; i
<* size
- 3 ; i
+= 2 ){
430 //check for phase error
431 if ( BitStream
[ i
+ 1 ]== BitStream
[ i
+ 2 ]) {
432 BitStream
[ bitnum
++]= 7 ;
435 if (( BitStream
[ i
]== 1 && BitStream
[ i
+ 1 ]== 0 ) || ( BitStream
[ i
]== 0 && BitStream
[ i
+ 1 ]== 1 )){
436 BitStream
[ bitnum
++]= 1 ^ invert
;
437 } else if (( BitStream
[ i
]== 0 && BitStream
[ i
+ 1 ]== 0 ) || ( BitStream
[ i
]== 1 && BitStream
[ i
+ 1 ]== 1 )){
438 BitStream
[ bitnum
++]= invert
;
440 BitStream
[ bitnum
++]= 7 ;
443 if ( bitnum
> MaxBits
) break ;
450 // demod gProxIIDemod
451 // error returns as -x
452 // success returns start position in BitStream
453 // BitStream must contain previously askrawdemod and biphasedemoded data
454 int gProxII_Demod ( uint8_t BitStream
[], size_t * size
)
457 uint8_t preamble
[] = { 1 , 1 , 1 , 1 , 1 , 0 };
459 uint8_t errChk
= preambleSearch ( BitStream
, preamble
, sizeof ( preamble
), size
, & startIdx
);
460 if ( errChk
== 0 ) return - 3 ; //preamble not found
461 if (* size
!= 96 ) return - 2 ; //should have found 96 bits
462 //check first 6 spacer bits to verify format
463 if (! BitStream
[ startIdx
+ 5 ] && ! BitStream
[ startIdx
+ 10 ] && ! BitStream
[ startIdx
+ 15 ] && ! BitStream
[ startIdx
+ 20 ] && ! BitStream
[ startIdx
+ 25 ] && ! BitStream
[ startIdx
+ 30 ]){
464 //confirmed proper separator bits found
465 //return start position
466 return ( int ) startIdx
;
468 return - 5 ; //spacer bits not found - not a valid gproxII
471 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
472 size_t fsk_wave_demod ( uint8_t * dest
, size_t size
, uint8_t fchigh
, uint8_t fclow
)
474 size_t last_transition
= 0 ;
477 if ( fchigh
== 0 ) fchigh
= 10 ;
478 if ( fclow
== 0 ) fclow
= 8 ;
479 //set the threshold close to 0 (graph) or 128 std to avoid static
480 uint8_t threshold_value
= 123 ;
481 size_t preLastSample
= 0 ;
482 size_t LastSample
= 0 ;
483 size_t currSample
= 0 ;
484 // sync to first lo-hi transition, and threshold
486 // Need to threshold first sample
487 // skip 160 samples to allow antenna/samples to settle
488 if ( dest
[ 160 ] < threshold_value
) dest
[ 0 ] = 0 ;
492 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
493 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
494 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
495 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
496 for ( idx
= 161 ; idx
< size
- 20 ; idx
++) {
497 // threshold current value
499 if ( dest
[ idx
] < threshold_value
) dest
[ idx
] = 0 ;
502 // Check for 0->1 transition
503 if ( dest
[ idx
- 1 ] < dest
[ idx
]) {
504 preLastSample
= LastSample
;
505 LastSample
= currSample
;
506 currSample
= idx
- last_transition
;
507 if ( currSample
< ( fclow
- 2 )){ //0-5 = garbage noise (or 0-3)
508 //do nothing with extra garbage
509 } else if ( currSample
< ( fchigh
- 1 )) { //6-8 = 8 sample waves (or 3-6 = 5)
510 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
511 if ( LastSample
> ( fchigh
- 2 ) && ( preLastSample
< ( fchigh
- 1 ) || preLastSample
== 0 )){
516 } else if ( currSample
> ( fchigh
) && ! numBits
) { //12 + and first bit = unusable garbage
517 //do nothing with beginning garbage
518 } 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)
520 } else { //9+ = 10 sample waves (or 6+ = 7)
523 last_transition
= idx
;
526 return numBits
; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
529 //translate 11111100000 to 10
530 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
531 size_t aggregate_bits ( uint8_t * dest
, size_t size
, uint8_t rfLen
,
532 uint8_t invert
, uint8_t fchigh
, uint8_t fclow
)
534 uint8_t lastval
= dest
[ 0 ];
538 for ( idx
= 1 ; idx
< size
; idx
++) {
540 if ( dest
[ idx
]== lastval
) continue ;
542 //find out how many bits (n) we collected
543 //if lastval was 1, we have a 1->0 crossing
544 if ( dest
[ idx
- 1 ]== 1 ) {
545 n
= ( n
* fclow
+ rfLen
/ 2 ) / rfLen
;
546 } else { // 0->1 crossing
547 n
= ( n
* fchigh
+ rfLen
/ 2 ) / rfLen
;
551 //add to our destination the bits we collected
552 memset ( dest
+ numBits
, dest
[ idx
- 1 ]^ invert
, n
);
557 // if valid extra bits at the end were all the same frequency - add them in
558 if ( n
> rfLen
/ fchigh
) {
559 if ( dest
[ idx
- 2 ]== 1 ) {
560 n
= ( n
* fclow
+ rfLen
/ 2 ) / rfLen
;
562 n
= ( n
* fchigh
+ rfLen
/ 2 ) / rfLen
;
564 memset ( dest
+ numBits
, dest
[ idx
- 1 ]^ invert
, n
);
570 //by marshmellow (from holiman's base)
571 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
572 int fskdemod ( uint8_t * dest
, size_t size
, uint8_t rfLen
, uint8_t invert
, uint8_t fchigh
, uint8_t fclow
)
575 size
= fsk_wave_demod ( dest
, size
, fchigh
, fclow
);
576 size
= aggregate_bits ( dest
, size
, rfLen
, invert
, fchigh
, fclow
);
580 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
581 int HIDdemodFSK ( uint8_t * dest
, size_t * size
, uint32_t * hi2
, uint32_t * hi
, uint32_t * lo
)
583 if ( justNoise ( dest
, * size
)) return - 1 ;
585 size_t numStart
= 0 , size2
=* size
, startIdx
= 0 ;
587 * size
= fskdemod ( dest
, size2
, 50 , 1 , 10 , 8 ); //fsk2a
588 if (* size
< 96 * 2 ) return - 2 ;
589 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
590 uint8_t preamble
[] = { 0 , 0 , 0 , 1 , 1 , 1 , 0 , 1 };
591 // find bitstring in array
592 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
593 if ( errChk
== 0 ) return - 3 ; //preamble not found
595 numStart
= startIdx
+ sizeof ( preamble
);
596 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
597 for ( size_t idx
= numStart
; ( idx
- numStart
) < * size
- sizeof ( preamble
); idx
+= 2 ){
598 if ( dest
[ idx
] == dest
[ idx
+ 1 ]){
599 return - 4 ; //not manchester data
601 * hi2
= (* hi2
<< 1 )|(* hi
>> 31 );
602 * hi
= (* hi
<< 1 )|(* lo
>> 31 );
603 //Then, shift in a 0 or one into low
604 if ( dest
[ idx
] && ! dest
[ idx
+ 1 ]) // 1 0
609 return ( int ) startIdx
;
612 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
613 int ParadoxdemodFSK ( uint8_t * dest
, size_t * size
, uint32_t * hi2
, uint32_t * hi
, uint32_t * lo
)
615 if ( justNoise ( dest
, * size
)) return - 1 ;
617 size_t numStart
= 0 , size2
=* size
, startIdx
= 0 ;
619 * size
= fskdemod ( dest
, size2
, 50 , 1 , 10 , 8 ); //fsk2a
620 if (* size
< 96 ) return - 2 ;
622 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
623 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 1 , 1 , 1 , 1 };
625 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
626 if ( errChk
== 0 ) return - 3 ; //preamble not found
628 numStart
= startIdx
+ sizeof ( preamble
);
629 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
630 for ( size_t idx
= numStart
; ( idx
- numStart
) < * size
- sizeof ( preamble
); idx
+= 2 ){
631 if ( dest
[ idx
] == dest
[ idx
+ 1 ])
632 return - 4 ; //not manchester data
633 * hi2
= (* hi2
<< 1 )|(* hi
>> 31 );
634 * hi
= (* hi
<< 1 )|(* lo
>> 31 );
635 //Then, shift in a 0 or one into low
636 if ( dest
[ idx
] && ! dest
[ idx
+ 1 ]) // 1 0
641 return ( int ) startIdx
;
644 int IOdemodFSK ( uint8_t * dest
, size_t size
)
646 if ( justNoise ( dest
, size
)) return - 1 ;
647 //make sure buffer has data
648 if ( size
< 66 * 64 ) return - 2 ;
650 size
= fskdemod ( dest
, size
, 64 , 1 , 10 , 8 ); // FSK2a RF/64
651 if ( size
< 65 ) return - 3 ; //did we get a good demod?
653 //0 10 20 30 40 50 60
655 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
656 //-----------------------------------------------------------------------------
657 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
659 //XSF(version)facility:codeone+codetwo
662 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
663 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), & size
, & startIdx
);
664 if ( errChk
== 0 ) return - 4 ; //preamble not found
666 if (! dest
[ startIdx
+ 8 ] && dest
[ startIdx
+ 17 ]== 1 && dest
[ startIdx
+ 26 ]== 1 && dest
[ startIdx
+ 35 ]== 1 && dest
[ startIdx
+ 44 ]== 1 && dest
[ startIdx
+ 53 ]== 1 ){
667 //confirmed proper separator bits found
668 //return start position
669 return ( int ) startIdx
;
675 // find viking preamble 0xF200 in already demoded data
676 int VikingDemod_AM ( uint8_t * dest
, size_t * size
) {
677 //make sure buffer has data
678 if (* size
< 64 * 2 ) return - 2 ;
681 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 };
682 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
683 if ( errChk
== 0 ) return - 4 ; //preamble not found
684 uint32_t checkCalc
= bytebits_to_byte ( dest
+ startIdx
, 8 ) ^
685 bytebits_to_byte ( dest
+ startIdx
+ 8 , 8 ) ^
686 bytebits_to_byte ( dest
+ startIdx
+ 16 , 8 ) ^
687 bytebits_to_byte ( dest
+ startIdx
+ 24 , 8 ) ^
688 bytebits_to_byte ( dest
+ startIdx
+ 32 , 8 ) ^
689 bytebits_to_byte ( dest
+ startIdx
+ 40 , 8 ) ^
690 bytebits_to_byte ( dest
+ startIdx
+ 48 , 8 ) ^
691 bytebits_to_byte ( dest
+ startIdx
+ 56 , 8 );
692 if ( checkCalc
!= 0xA8 ) return - 5 ;
693 if (* size
!= 64 ) return - 6 ;
694 //return start position
695 return ( int ) startIdx
;
698 // find presco preamble 0x10D in already demoded data
699 int PrescoDemod ( uint8_t * dest
, size_t * size
) {
700 //make sure buffer has data
701 if (* size
< 64 * 2 ) return - 2 ;
704 uint8_t preamble
[] = { 1 , 0 , 0 , 0 , 0 , 1 , 1 , 0 , 1 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
705 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
706 if ( errChk
== 0 ) return - 4 ; //preamble not found
707 //return start position
708 return ( int ) startIdx
;
711 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
712 // BitStream must contain previously askrawdemod and biphasedemoded data
713 int FDXBdemodBI ( uint8_t * dest
, size_t * size
)
715 //make sure buffer has enough data
716 if (* size
< 128 ) return - 1 ;
719 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
721 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
722 if ( errChk
== 0 ) return - 2 ; //preamble not found
723 return ( int ) startIdx
;
727 // FSK Demod then try to locate an AWID ID
728 int AWIDdemodFSK ( uint8_t * dest
, size_t * size
)
730 //make sure buffer has enough data
731 if (* size
< 96 * 50 ) return - 1 ;
733 if ( justNoise ( dest
, * size
)) return - 2 ;
736 * size
= fskdemod ( dest
, * size
, 50 , 1 , 10 , 8 ); // fsk2a RF/50
737 if (* size
< 96 ) return - 3 ; //did we get a good demod?
739 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
741 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
742 if ( errChk
== 0 ) return - 4 ; //preamble not found
743 if (* size
!= 96 ) return - 5 ;
744 return ( int ) startIdx
;
748 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
749 int PyramiddemodFSK ( uint8_t * dest
, size_t * size
)
751 //make sure buffer has data
752 if (* size
< 128 * 50 ) return - 5 ;
754 //test samples are not just noise
755 if ( justNoise ( dest
, * size
)) return - 1 ;
758 * size
= fskdemod ( dest
, * size
, 50 , 1 , 10 , 8 ); // fsk2a RF/50
759 if (* size
< 128 ) return - 2 ; //did we get a good demod?
761 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
763 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
764 if ( errChk
== 0 ) return - 4 ; //preamble not found
765 if (* size
!= 128 ) return - 3 ;
766 return ( int ) startIdx
;
769 // find nedap preamble in already demoded data
770 int NedapDemod ( uint8_t * dest
, size_t * size
) {
771 //make sure buffer has data
772 if (* size
< 128 ) return - 3 ;
775 //uint8_t preamble[] = {1,1,1,1,1,1,1,1,1,0,0,0,1};
776 uint8_t preamble
[] = { 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 0 };
777 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
778 if ( errChk
== 0 ) return - 4 ; //preamble not found
779 return ( int ) startIdx
;
783 // to detect a wave that has heavily clipped (clean) samples
784 uint8_t DetectCleanAskWave ( uint8_t dest
[], size_t size
, uint8_t high
, uint8_t low
)
786 bool allArePeaks
= true ;
788 size_t loopEnd
= 512 + 160 ;
789 if ( loopEnd
> size
) loopEnd
= size
;
790 for ( size_t i
= 160 ; i
< loopEnd
; i
++){
791 if ( dest
[ i
]> low
&& dest
[ i
]< high
)
797 if ( cntPeaks
> 300 ) return true ;
802 // to help detect clocks on heavily clipped samples
803 // based on count of low to low
804 int DetectStrongAskClock ( uint8_t dest
[], size_t size
, uint8_t high
, uint8_t low
)
806 uint8_t fndClk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 128 };
810 // get to first full low to prime loop and skip incomplete first pulse
811 while (( dest
[ i
] < high
) && ( i
< size
))
813 while (( dest
[ i
] > low
) && ( i
< size
))
816 // loop through all samples
818 // measure from low to low
819 while (( dest
[ i
] > low
) && ( i
< size
))
822 while (( dest
[ i
] < high
) && ( i
< size
))
824 while (( dest
[ i
] > low
) && ( i
< size
))
826 //get minimum measured distance
827 if ( i
- startwave
< minClk
&& i
< size
)
828 minClk
= i
- startwave
;
831 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: detectstrongASKclk smallest wave: %d" , minClk
);
832 for ( uint8_t clkCnt
= 0 ; clkCnt
< 7 ; clkCnt
++) {
833 if ( minClk
>= fndClk
[ clkCnt
]-( fndClk
[ clkCnt
]/ 8 ) && minClk
<= fndClk
[ clkCnt
]+ 1 )
834 return fndClk
[ clkCnt
];
840 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
841 // maybe somehow adjust peak trimming value based on samples to fix?
842 // return start index of best starting position for that clock and return clock (by reference)
843 int DetectASKClock ( uint8_t dest
[], size_t size
, int * clock
, int maxErr
)
846 uint8_t clk
[] = { 255 , 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 };
848 uint8_t loopCnt
= 255 ; //don't need to loop through entire array...
849 if ( size
<= loopCnt
+ 60 ) return - 1 ; //not enough samples
850 size
-= 60 ; //sometimes there is a strange end wave - filter out this....
851 //if we already have a valid clock
854 if ( clk
[ i
] == * clock
) clockFnd
= i
;
855 //clock found but continue to find best startpos
857 //get high and low peak
859 if ( getHiLo ( dest
, loopCnt
, & peak
, & low
, 75 , 75 ) < 1 ) return - 1 ;
861 //test for large clean peaks
863 if ( DetectCleanAskWave ( dest
, size
, peak
, low
)== 1 ){
864 int ans
= DetectStrongAskClock ( dest
, size
, peak
, low
);
865 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d" , ans
);
866 for ( i
= clkEnd
- 1 ; i
> 0 ; i
--){
870 return 0 ; // for strong waves i don't use the 'best start position' yet...
871 //break; //clock found but continue to find best startpos [not yet]
877 uint8_t clkCnt
, tol
= 0 ;
878 uint16_t bestErr
[]={ 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 };
879 uint8_t bestStart
[]={ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
881 size_t arrLoc
, loopEnd
;
889 //test each valid clock from smallest to greatest to see which lines up
890 for (; clkCnt
< clkEnd
; clkCnt
++){
891 if ( clk
[ clkCnt
] <= 32 ){
896 //if no errors allowed - keep start within the first clock
897 if (! maxErr
&& size
> clk
[ clkCnt
]* 2 + tol
&& clk
[ clkCnt
]< 128 ) loopCnt
= clk
[ clkCnt
]* 2 ;
898 bestErr
[ clkCnt
]= 1000 ;
899 //try lining up the peaks by moving starting point (try first few clocks)
900 for ( ii
= 0 ; ii
< loopCnt
; ii
++){
901 if ( dest
[ ii
] < peak
&& dest
[ ii
] > low
) continue ;
904 // now that we have the first one lined up test rest of wave array
905 loopEnd
= (( size
- ii
- tol
) / clk
[ clkCnt
]) - 1 ;
906 for ( i
= 0 ; i
< loopEnd
; ++ i
){
907 arrLoc
= ii
+ ( i
* clk
[ clkCnt
]);
908 if ( dest
[ arrLoc
] >= peak
|| dest
[ arrLoc
] <= low
){
909 } else if ( dest
[ arrLoc
- tol
] >= peak
|| dest
[ arrLoc
- tol
] <= low
){
910 } else if ( dest
[ arrLoc
+ tol
] >= peak
|| dest
[ arrLoc
+ tol
] <= low
){
911 } else { //error no peak detected
915 //if we found no errors then we can stop here and a low clock (common clocks)
916 // this is correct one - return this clock
917 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: clk %d, err %d, startpos %d, endpos %d" , clk
[ clkCnt
], errCnt
, ii
, i
);
918 if ( errCnt
== 0 && clkCnt
< 7 ) {
919 if (! clockFnd
) * clock
= clk
[ clkCnt
];
922 //if we found errors see if it is lowest so far and save it as best run
923 if ( errCnt
< bestErr
[ clkCnt
]){
924 bestErr
[ clkCnt
]= errCnt
;
925 bestStart
[ clkCnt
]= ii
;
931 for ( iii
= 1 ; iii
< clkEnd
; ++ iii
){
932 if ( bestErr
[ iii
] < bestErr
[ best
]){
933 if ( bestErr
[ iii
] == 0 ) bestErr
[ iii
]= 1 ;
934 // current best bit to error ratio vs new bit to error ratio
935 if ( ( size
/ clk
[ best
])/ bestErr
[ best
] < ( size
/ clk
[ iii
])/ bestErr
[ iii
] ){
939 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
]);
941 if (! clockFnd
) * clock
= clk
[ best
];
942 return bestStart
[ best
];
946 //detect psk clock by reading each phase shift
947 // a phase shift is determined by measuring the sample length of each wave
948 int DetectPSKClock ( uint8_t dest
[], size_t size
, int clock
)
950 uint8_t clk
[]={ 255 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 }; //255 is not a valid clock
951 uint16_t loopCnt
= 4096 ; //don't need to loop through entire array...
952 if ( size
== 0 ) return 0 ;
953 if ( size
< loopCnt
) loopCnt
= size
- 20 ;
955 //if we already have a valid clock quit
958 if ( clk
[ i
] == clock
) return clock
;
960 size_t waveStart
= 0 , waveEnd
= 0 , firstFullWave
= 0 , lastClkBit
= 0 ;
961 uint8_t clkCnt
, fc
= 0 , fullWaveLen
= 0 , tol
= 1 ;
962 uint16_t peakcnt
= 0 , errCnt
= 0 , waveLenCnt
= 0 ;
963 uint16_t bestErr
[]={ 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 };
964 uint16_t peaksdet
[]={ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
965 fc
= countFC ( dest
, size
, 0 );
966 if ( fc
!= 2 && fc
!= 4 && fc
!= 8 ) return - 1 ;
967 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: FC: %d" , fc
);
969 //find first full wave
970 for ( i
= 160 ; i
< loopCnt
; i
++){
971 if ( dest
[ i
] < dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
972 if ( waveStart
== 0 ) {
974 //prnt("DEBUG: waveStart: %d",waveStart);
977 //prnt("DEBUG: waveEnd: %d",waveEnd);
978 waveLenCnt
= waveEnd
- waveStart
;
979 if ( waveLenCnt
> fc
){
980 firstFullWave
= waveStart
;
981 fullWaveLen
= waveLenCnt
;
988 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: firstFullWave: %d, waveLen: %d" , firstFullWave
, fullWaveLen
);
990 //test each valid clock from greatest to smallest to see which lines up
991 for ( clkCnt
= 7 ; clkCnt
>= 1 ; clkCnt
--){
992 lastClkBit
= firstFullWave
; //set end of wave as clock align
996 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: clk: %d, lastClkBit: %d" , clk
[ clkCnt
], lastClkBit
);
998 for ( i
= firstFullWave
+ fullWaveLen
- 1 ; i
< loopCnt
- 2 ; i
++){
999 //top edge of wave = start of new wave
1000 if ( dest
[ i
] < dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1001 if ( waveStart
== 0 ) {
1006 waveLenCnt
= waveEnd
- waveStart
;
1007 if ( waveLenCnt
> fc
){
1008 //if this wave is a phase shift
1009 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
);
1010 if ( i
+ 1 >= lastClkBit
+ clk
[ clkCnt
] - tol
){ //should be a clock bit
1012 lastClkBit
+= clk
[ clkCnt
];
1013 } else if ( i
< lastClkBit
+ 8 ){
1014 //noise after a phase shift - ignore
1015 } else { //phase shift before supposed to based on clock
1018 } else if ( i
+ 1 > lastClkBit
+ clk
[ clkCnt
] + tol
+ fc
){
1019 lastClkBit
+= clk
[ clkCnt
]; //no phase shift but clock bit
1028 if ( errCnt
<= bestErr
[ clkCnt
]) bestErr
[ clkCnt
]= errCnt
;
1029 if ( peakcnt
> peaksdet
[ clkCnt
]) peaksdet
[ clkCnt
]= peakcnt
;
1031 //all tested with errors
1032 //return the highest clk with the most peaks found
1034 for ( i
= 7 ; i
>= 1 ; i
--){
1035 if ( peaksdet
[ i
] > peaksdet
[ best
]) {
1038 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d" , clk
[ i
], peaksdet
[ i
], bestErr
[ i
], clk
[ best
]);
1043 int DetectStrongNRZClk ( uint8_t * dest
, size_t size
, int peak
, int low
){
1044 //find shortest transition from high to low
1046 size_t transition1
= 0 ;
1047 int lowestTransition
= 255 ;
1048 bool lastWasHigh
= false ;
1050 //find first valid beginning of a high or low wave
1051 while (( dest
[ i
] >= peak
|| dest
[ i
] <= low
) && ( i
< size
))
1053 while (( dest
[ i
] < peak
&& dest
[ i
] > low
) && ( i
< size
))
1055 lastWasHigh
= ( dest
[ i
] >= peak
);
1057 if ( i
== size
) return 0 ;
1060 for (; i
< size
; i
++) {
1061 if (( dest
[ i
] >= peak
&& ! lastWasHigh
) || ( dest
[ i
] <= low
&& lastWasHigh
)) {
1062 lastWasHigh
= ( dest
[ i
] >= peak
);
1063 if ( i
- transition1
< lowestTransition
) lowestTransition
= i
- transition1
;
1067 if ( lowestTransition
== 255 ) lowestTransition
= 0 ;
1068 if ( g_debugMode
== 2 ) prnt ( "DEBUG NRZ: detectstrongNRZclk smallest wave: %d" , lowestTransition
);
1069 return lowestTransition
;
1073 //detect nrz clock by reading #peaks vs no peaks(or errors)
1074 int DetectNRZClock ( uint8_t dest
[], size_t size
, int clock
)
1077 uint8_t clk
[]={ 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 };
1078 size_t loopCnt
= 4096 ; //don't need to loop through entire array...
1079 if ( size
== 0 ) return 0 ;
1080 if ( size
< loopCnt
) loopCnt
= size
- 20 ;
1081 //if we already have a valid clock quit
1083 if ( clk
[ i
] == clock
) return clock
;
1085 //get high and low peak
1087 if ( getHiLo ( dest
, loopCnt
, & peak
, & low
, 75 , 75 ) < 1 ) return 0 ;
1089 int lowestTransition
= DetectStrongNRZClk ( dest
, size
- 20 , peak
, low
);
1093 uint16_t smplCnt
= 0 ;
1094 int16_t peakcnt
= 0 ;
1095 int16_t peaksdet
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1096 uint16_t maxPeak
= 255 ;
1097 bool firstpeak
= false ;
1098 //test for large clipped waves
1099 for ( i
= 0 ; i
< loopCnt
; i
++){
1100 if ( dest
[ i
] >= peak
|| dest
[ i
] <= low
){
1101 if (! firstpeak
) continue ;
1106 if ( maxPeak
> smplCnt
){
1108 //prnt("maxPk: %d",maxPeak);
1111 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1116 bool errBitHigh
= 0 ;
1118 uint8_t ignoreCnt
= 0 ;
1119 uint8_t ignoreWindow
= 4 ;
1120 bool lastPeakHigh
= 0 ;
1123 //test each valid clock from smallest to greatest to see which lines up
1124 for ( clkCnt
= 0 ; clkCnt
< 8 ; ++ clkCnt
){
1125 //ignore clocks smaller than smallest peak
1126 if ( clk
[ clkCnt
] < maxPeak
- ( clk
[ clkCnt
]/ 4 )) continue ;
1127 //try lining up the peaks by moving starting point (try first 256)
1128 for ( ii
= 20 ; ii
< loopCnt
; ++ ii
){
1129 if (( dest
[ ii
] >= peak
) || ( dest
[ ii
] <= low
)){
1133 lastBit
= ii
- clk
[ clkCnt
];
1134 //loop through to see if this start location works
1135 for ( i
= ii
; i
< size
- 20 ; ++ i
) {
1136 //if we are at a clock bit
1137 if (( i
>= lastBit
+ clk
[ clkCnt
] - tol
) && ( i
<= lastBit
+ clk
[ clkCnt
] + tol
)) {
1139 if ( dest
[ i
] >= peak
|| dest
[ i
] <= low
) {
1140 //if same peak don't count it
1141 if (( dest
[ i
] >= peak
&& ! lastPeakHigh
) || ( dest
[ i
] <= low
&& lastPeakHigh
)) {
1144 lastPeakHigh
= ( dest
[ i
] >= peak
);
1147 ignoreCnt
= ignoreWindow
;
1148 lastBit
+= clk
[ clkCnt
];
1149 } else if ( i
== lastBit
+ clk
[ clkCnt
] + tol
) {
1150 lastBit
+= clk
[ clkCnt
];
1152 //else if not a clock bit and no peaks
1153 } else if ( dest
[ i
] < peak
&& dest
[ i
] > low
){
1156 if ( errBitHigh
== true ) peakcnt
--;
1161 // else if not a clock bit but we have a peak
1162 } else if (( dest
[ i
]>= peak
|| dest
[ i
]<= low
) && (! bitHigh
)) {
1163 //error bar found no clock...
1167 if ( peakcnt
> peaksdet
[ clkCnt
]) {
1168 peaksdet
[ clkCnt
]= peakcnt
;
1175 for ( iii
= 7 ; iii
> 0 ; iii
--){
1176 if (( peaksdet
[ iii
] >= ( peaksdet
[ best
]- 1 )) && ( peaksdet
[ iii
] <= peaksdet
[ best
]+ 1 ) && lowestTransition
) {
1177 if ( clk
[ iii
] > ( lowestTransition
- ( clk
[ iii
]/ 8 )) && clk
[ iii
] < ( lowestTransition
+ ( clk
[ iii
]/ 8 ))) {
1180 } else if ( peaksdet
[ iii
] > peaksdet
[ best
]){
1183 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
);
1190 // convert psk1 demod to psk2 demod
1191 // only transition waves are 1s
1192 void psk1TOpsk2 ( uint8_t * BitStream
, size_t size
)
1195 uint8_t lastBit
= BitStream
[ 0 ];
1196 for (; i
< size
; i
++){
1197 if ( BitStream
[ i
]== 7 ){
1199 } else if ( lastBit
!= BitStream
[ i
]){
1200 lastBit
= BitStream
[ i
];
1210 // convert psk2 demod to psk1 demod
1211 // from only transition waves are 1s to phase shifts change bit
1212 void psk2TOpsk1 ( uint8_t * BitStream
, size_t size
)
1215 for ( size_t i
= 0 ; i
< size
; i
++){
1216 if ( BitStream
[ i
]== 1 ){
1224 // redesigned by marshmellow adjusted from existing decode functions
1225 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1226 int indala26decode ( uint8_t * bitStream
, size_t * size
, uint8_t * invert
)
1228 //26 bit 40134 format (don't know other formats)
1229 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 };
1230 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 };
1231 size_t startidx
= 0 ;
1232 if (! preambleSearch ( bitStream
, preamble
, sizeof ( preamble
), size
, & startidx
)){
1233 // if didn't find preamble try again inverting
1234 if (! preambleSearch ( bitStream
, preamble_i
, sizeof ( preamble_i
), size
, & startidx
)) return - 1 ;
1237 if (* size
!= 64 && * size
!= 224 ) return - 2 ;
1239 for ( size_t i
= startidx
; i
< * size
; i
++)
1242 return ( int ) startidx
;
1245 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1246 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1247 int nrzRawDemod ( uint8_t * dest
, size_t * size
, int * clk
, int * invert
){
1248 if ( justNoise ( dest
, * size
)) return - 1 ;
1249 * clk
= DetectNRZClock ( dest
, * size
, * clk
);
1250 if (* clk
== 0 ) return - 2 ;
1251 size_t i
, gLen
= 4096 ;
1252 if ( gLen
>* size
) gLen
= * size
- 20 ;
1254 if ( getHiLo ( dest
, gLen
, & high
, & low
, 75 , 75 ) < 1 ) return - 3 ; //25% fuzz on high 25% fuzz on low
1257 //convert wave samples to 1's and 0's
1258 for ( i
= 20 ; i
< * size
- 20 ; i
++){
1259 if ( dest
[ i
] >= high
) bit
= 1 ;
1260 if ( dest
[ i
] <= low
) bit
= 0 ;
1263 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1266 for ( i
= 21 ; i
< * size
- 20 ; i
++) {
1267 //if transition detected or large number of same bits - store the passed bits
1268 if ( dest
[ i
] != dest
[ i
- 1 ] || ( i
- lastBit
) == ( 10 * * clk
)) {
1269 memset ( dest
+ numBits
, dest
[ i
- 1 ] ^ * invert
, ( i
- lastBit
+ (* clk
/ 4 )) / * clk
);
1270 numBits
+= ( i
- lastBit
+ (* clk
/ 4 )) / * clk
;
1279 //detects the bit clock for FSK given the high and low Field Clocks
1280 uint8_t detectFSKClk ( uint8_t * BitStream
, size_t size
, uint8_t fcHigh
, uint8_t fcLow
)
1282 uint8_t clk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 0 };
1283 uint16_t rfLens
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1284 uint8_t rfCnts
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1285 uint8_t rfLensFnd
= 0 ;
1286 uint8_t lastFCcnt
= 0 ;
1287 uint16_t fcCounter
= 0 ;
1288 uint16_t rfCounter
= 0 ;
1289 uint8_t firstBitFnd
= 0 ;
1291 if ( size
== 0 ) return 0 ;
1293 uint8_t fcTol
= (( fcHigh
* 100 - fcLow
* 100 )/ 2 + 50 )/ 100 ; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1298 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
1299 // prime i to first peak / up transition
1300 for ( i
= 160 ; i
< size
- 20 ; i
++)
1301 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
]>= BitStream
[ i
+ 1 ])
1304 for (; i
< size
- 20 ; i
++){
1308 if ( BitStream
[ i
] <= BitStream
[ i
- 1 ] || BitStream
[ i
] < BitStream
[ i
+ 1 ])
1311 // if we got less than the small fc + tolerance then set it to the small fc
1312 if ( fcCounter
< fcLow
+ fcTol
)
1314 else //set it to the large fc
1317 //look for bit clock (rf/xx)
1318 if (( fcCounter
< lastFCcnt
|| fcCounter
> lastFCcnt
)){
1319 //not the same size as the last wave - start of new bit sequence
1320 if ( firstBitFnd
> 1 ){ //skip first wave change - probably not a complete bit
1321 for ( int ii
= 0 ; ii
< 15 ; ii
++){
1322 if ( rfLens
[ ii
] >= ( rfCounter
- 4 ) && rfLens
[ ii
] <= ( rfCounter
+ 4 )){
1328 if ( rfCounter
> 0 && rfLensFnd
< 15 ){
1329 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1330 rfCnts
[ rfLensFnd
]++;
1331 rfLens
[ rfLensFnd
++] = rfCounter
;
1337 lastFCcnt
= fcCounter
;
1341 uint8_t rfHighest
= 15 , rfHighest2
= 15 , rfHighest3
= 15 ;
1343 for ( i
= 0 ; i
< 15 ; i
++){
1344 //get highest 2 RF values (might need to get more values to compare or compare all?)
1345 if ( rfCnts
[ i
]> rfCnts
[ rfHighest
]){
1346 rfHighest3
= rfHighest2
;
1347 rfHighest2
= rfHighest
;
1349 } else if ( rfCnts
[ i
]> rfCnts
[ rfHighest2
]){
1350 rfHighest3
= rfHighest2
;
1352 } else if ( rfCnts
[ i
]> rfCnts
[ rfHighest3
]){
1355 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: RF %d, cnts %d" , rfLens
[ i
], rfCnts
[ i
]);
1357 // set allowed clock remainder tolerance to be 1 large field clock length+1
1358 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1359 uint8_t tol1
= fcHigh
+ 1 ;
1361 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d" , rfLens
[ rfHighest
], rfLens
[ rfHighest2
], rfLens
[ rfHighest3
]);
1363 // loop to find the highest clock that has a remainder less than the tolerance
1364 // compare samples counted divided by
1365 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1367 for (; ii
>= 2 ; ii
--){
1368 if ( rfLens
[ rfHighest
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1369 if ( rfLens
[ rfHighest2
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest2
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1370 if ( rfLens
[ rfHighest3
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest3
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1371 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: clk %d divides into the 3 most rf values within tolerance" , clk
[ ii
]);
1378 if ( ii
< 0 ) return 0 ; // oops we went too far
1384 //countFC is to detect the field clock lengths.
1385 //counts and returns the 2 most common wave lengths
1386 //mainly used for FSK field clock detection
1387 uint16_t countFC ( uint8_t * BitStream
, size_t size
, uint8_t fskAdj
)
1389 uint8_t fcLens
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1390 uint16_t fcCnts
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1391 uint8_t fcLensFnd
= 0 ;
1392 uint8_t lastFCcnt
= 0 ;
1393 uint8_t fcCounter
= 0 ;
1395 if ( size
== 0 ) return 0 ;
1397 // prime i to first up transition
1398 for ( i
= 160 ; i
< size
- 20 ; i
++)
1399 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
] >= BitStream
[ i
+ 1 ])
1402 for (; i
< size
- 20 ; i
++){
1403 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
] >= BitStream
[ i
+ 1 ]){
1404 // new up transition
1407 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1408 if ( lastFCcnt
== 5 && fcCounter
== 9 ) fcCounter
--;
1409 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1410 if (( fcCounter
== 9 ) || fcCounter
== 4 ) fcCounter
++;
1411 // save last field clock count (fc/xx)
1412 lastFCcnt
= fcCounter
;
1414 // find which fcLens to save it to:
1415 for ( int ii
= 0 ; ii
< 15 ; ii
++){
1416 if ( fcLens
[ ii
]== fcCounter
){
1422 if ( fcCounter
> 0 && fcLensFnd
< 15 ){
1424 fcCnts
[ fcLensFnd
]++;
1425 fcLens
[ fcLensFnd
++]= fcCounter
;
1434 uint8_t best1
= 14 , best2
= 14 , best3
= 14 ;
1436 // go through fclens and find which ones are bigest 2
1437 for ( i
= 0 ; i
< 15 ; i
++){
1438 // get the 3 best FC values
1439 if ( fcCnts
[ i
]> maxCnt1
) {
1444 } else if ( fcCnts
[ i
]> fcCnts
[ best2
]){
1447 } else if ( fcCnts
[ i
]> fcCnts
[ best3
]){
1450 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
]);
1452 if ( fcLens
[ best1
]== 0 ) return 0 ;
1453 uint8_t fcH
= 0 , fcL
= 0 ;
1454 if ( fcLens
[ best1
]> fcLens
[ best2
]){
1461 if (( size
- 180 )/ fcH
/ 3 > fcCnts
[ best1
]+ fcCnts
[ best2
]) {
1462 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
]);
1463 return 0 ; //lots of waves not psk or fsk
1465 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1467 uint16_t fcs
= ((( uint16_t ) fcH
)<< 8 ) | fcL
;
1468 if ( fskAdj
) return fcs
;
1469 return fcLens
[ best1
];
1472 //by marshmellow - demodulate PSK1 wave
1473 //uses wave lengths (# Samples)
1474 int pskRawDemod ( uint8_t dest
[], size_t * size
, int * clock
, int * invert
)
1476 if ( size
== 0 ) return - 1 ;
1477 uint16_t loopCnt
= 4096 ; //don't need to loop through entire array...
1478 if (* size
< loopCnt
) loopCnt
= * size
;
1481 uint8_t curPhase
= * invert
;
1482 size_t i
, waveStart
= 1 , waveEnd
= 0 , firstFullWave
= 0 , lastClkBit
= 0 ;
1483 uint8_t fc
= 0 , fullWaveLen
= 0 , tol
= 1 ;
1484 uint16_t errCnt
= 0 , waveLenCnt
= 0 ;
1485 fc
= countFC ( dest
, * size
, 0 );
1486 if ( fc
!= 2 && fc
!= 4 && fc
!= 8 ) return - 1 ;
1487 //PrintAndLog("DEBUG: FC: %d",fc);
1488 * clock
= DetectPSKClock ( dest
, * size
, * clock
);
1489 if (* clock
== 0 ) return - 1 ;
1490 int avgWaveVal
= 0 , lastAvgWaveVal
= 0 ;
1491 //find first phase shift
1492 for ( i
= 0 ; i
< loopCnt
; i
++){
1493 if ( dest
[ i
]+ fc
< dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1495 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1496 waveLenCnt
= waveEnd
- waveStart
;
1497 if ( waveLenCnt
> fc
&& waveStart
> fc
&& !( waveLenCnt
> fc
+ 2 )){ //not first peak and is a large wave but not out of whack
1498 lastAvgWaveVal
= avgWaveVal
/( waveLenCnt
);
1499 firstFullWave
= waveStart
;
1500 fullWaveLen
= waveLenCnt
;
1501 //if average wave value is > graph 0 then it is an up wave or a 1
1502 if ( lastAvgWaveVal
> 123 ) curPhase
^= 1 ; //fudge graph 0 a little 123 vs 128
1508 avgWaveVal
+= dest
[ i
+ 2 ];
1510 if ( firstFullWave
== 0 ) {
1511 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1512 // so skip a little to ensure we are past any Start Signal
1513 firstFullWave
= 160 ;
1514 memset ( dest
, curPhase
, firstFullWave
/ * clock
);
1516 memset ( dest
, curPhase
^ 1 , firstFullWave
/ * clock
);
1519 numBits
+= ( firstFullWave
/ * clock
);
1520 //set start of wave as clock align
1521 lastClkBit
= firstFullWave
;
1522 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: firstFullWave: %u, waveLen: %u" , firstFullWave
, fullWaveLen
);
1523 if ( g_debugMode
== 2 ) prnt ( "DEBUG: clk: %d, lastClkBit: %u, fc: %u" , * clock
, lastClkBit
,( unsigned int ) fc
);
1525 dest
[ numBits
++] = curPhase
; //set first read bit
1526 for ( i
= firstFullWave
+ fullWaveLen
- 1 ; i
< * size
- 3 ; i
++){
1527 //top edge of wave = start of new wave
1528 if ( dest
[ i
]+ fc
< dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1529 if ( waveStart
== 0 ) {
1532 avgWaveVal
= dest
[ i
+ 1 ];
1535 waveLenCnt
= waveEnd
- waveStart
;
1536 lastAvgWaveVal
= avgWaveVal
/ waveLenCnt
;
1537 if ( waveLenCnt
> fc
){
1538 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1539 //this wave is a phase shift
1540 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1541 if ( i
+ 1 >= lastClkBit
+ * clock
- tol
){ //should be a clock bit
1543 dest
[ numBits
++] = curPhase
;
1544 lastClkBit
+= * clock
;
1545 } else if ( i
< lastClkBit
+ 10 + fc
){
1546 //noise after a phase shift - ignore
1547 } else { //phase shift before supposed to based on clock
1549 dest
[ numBits
++] = 7 ;
1551 } else if ( i
+ 1 > lastClkBit
+ * clock
+ tol
+ fc
){
1552 lastClkBit
+= * clock
; //no phase shift but clock bit
1553 dest
[ numBits
++] = curPhase
;
1559 avgWaveVal
+= dest
[ i
+ 1 ];
1566 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1567 bool DetectST ( uint8_t buffer
[], size_t * size
, int * foundclock
) {
1568 size_t bufsize
= * size
;
1569 //need to loop through all samples and identify our clock, look for the ST pattern
1570 uint8_t fndClk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 128 };
1573 int i
, j
, skip
, start
, end
, low
, high
, minClk
, waveStart
;
1574 bool complete
= false ;
1575 int tmpbuff
[ bufsize
/ 64 ];
1576 int waveLen
[ bufsize
/ 64 ];
1577 size_t testsize
= ( bufsize
< 512 ) ? bufsize
: 512 ;
1580 memset ( tmpbuff
, 0 , sizeof ( tmpbuff
));
1582 if ( getHiLo ( buffer
, testsize
, & high
, & low
, 80 , 80 ) == - 1 ) {
1583 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: just noise detected - quitting" );
1584 return false ; //just noise
1589 // get to first full low to prime loop and skip incomplete first pulse
1590 while (( buffer
[ i
] < high
) && ( i
< bufsize
))
1592 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1596 // populate tmpbuff buffer with pulse lengths
1597 while ( i
< bufsize
) {
1598 // measure from low to low
1599 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1602 while (( buffer
[ i
] < high
) && ( i
< bufsize
))
1604 //first high point for this wave
1606 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1608 if ( j
>= ( bufsize
/ 64 )) {
1611 waveLen
[ j
] = i
- waveStart
; //first high to first low
1612 tmpbuff
[ j
++] = i
- start
;
1613 if ( i
- start
< minClk
&& i
< bufsize
) {
1617 // set clock - might be able to get this externally and remove this work...
1619 for ( uint8_t clkCnt
= 0 ; clkCnt
< 7 ; clkCnt
++) {
1620 tol
= fndClk
[ clkCnt
]/ 8 ;
1621 if ( minClk
>= fndClk
[ clkCnt
]- tol
&& minClk
<= fndClk
[ clkCnt
]+ 1 ) {
1626 // clock not found - ERROR
1628 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: clock not found - quitting" );
1635 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1637 for ( i
= 0 ; i
< j
- 4 ; ++ i
) {
1639 if ( tmpbuff
[ i
] >= clk
* 1 - tol
&& tmpbuff
[ i
] <= ( clk
* 2 )+ tol
&& waveLen
[ i
] < clk
+ tol
) { //1 to 2 clocks depending on 2 bits prior
1640 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
1641 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
1642 if ( tmpbuff
[ i
+ 3 ] >= clk
* 1 - tol
&& tmpbuff
[ i
+ 3 ] <= clk
* 2 + tol
) { //1 to 2 clocks for end of ST + first bit
1650 // first ST not found - ERROR
1652 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: first STT not found - quitting" );
1655 if ( waveLen
[ i
+ 2 ] > clk
* 1 + tol
)
1660 // skip over the remainder of ST
1661 skip
+= clk
* 7 / 2 ; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1663 // now do it again to find the end
1665 for ( i
+= 3 ; i
< j
- 4 ; ++ i
) {
1667 if ( tmpbuff
[ i
] >= clk
* 1 - tol
&& tmpbuff
[ i
] <= ( clk
* 2 )+ tol
) { //1 to 2 clocks depending on 2 bits prior
1668 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
1669 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
1670 if ( tmpbuff
[ i
+ 3 ] >= clk
* 1 - tol
&& tmpbuff
[ i
+ 3 ] <= clk
* 2 + tol
) { //1 to 2 clocks for end of ST + first bit
1679 //didn't find second ST - ERROR
1681 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: second STT not found - quitting" );
1684 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
);
1685 //now begin to trim out ST so we can use normal demod cmds
1687 size_t datalen
= end
- start
;
1688 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1689 if ( datalen
% clk
> clk
/ 8 ) {
1690 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting" , datalen
, clk
, datalen
% clk
);
1693 // padd the amount off - could be problematic... but shouldn't happen often
1694 datalen
+= datalen
% clk
;
1696 // if datalen is less than one t55xx block - ERROR
1697 if ( datalen
/ clk
< 8 * 4 ) {
1698 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: datalen is less than 1 full t55xx block - quitting" );
1701 size_t dataloc
= start
;
1704 // warning - overwriting buffer given with raw wave data with ST removed...
1705 while ( dataloc
< bufsize
-( clk
/ 2 ) ) {
1706 //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)
1707 if ( buffer
[ dataloc
]< high
&& buffer
[ dataloc
]> low
&& buffer
[ dataloc
+ 3 ]< high
&& buffer
[ dataloc
+ 3 ]> low
) {
1708 for ( i
= 0 ; i
< clk
/ 2 - tol
; ++ i
) {
1709 buffer
[ dataloc
+ i
] = high
+ 5 ;
1712 for ( i
= 0 ; i
< datalen
; ++ i
) {
1713 if ( i
+ newloc
< bufsize
) {
1714 if ( i
+ newloc
< dataloc
)
1715 buffer
[ i
+ newloc
] = buffer
[ dataloc
];
1721 //skip next ST - we just assume it will be there from now on...