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cvs.zerfleddert.de Git - proxmark3-svn/blob - common/lfdemod.c
a32d3b85e492401c2d04ea971789d23378bf8f3f
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 //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 if ( g_debugMode
) prnt ( "DEBUG: ans: %d, ptype: %d, bits: %08X" , ans
, pType
, bits
);
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 if ( word
+ pLen
>= bLen
) break ;
83 j
--; // overwrite parity with next data
84 // if parity fails then return 0
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
93 // if we got here then all the parities passed
94 //return ID start index and size
99 // takes a array of binary values, length of bits per parity (includes parity bit),
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
102 size_t addParity ( uint8_t * BitSource
, uint8_t * dest
, uint8_t sourceLen
, uint8_t pLen
, uint8_t pType
)
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
]);
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
++)
132 num
= ( num
<< 1 ) | (* src
);
138 //least significant bit first
139 uint32_t bytebits_to_byteLSBF ( uint8_t * src
, size_t numbits
)
142 for ( int i
= 0 ; i
< numbits
; i
++)
144 num
= ( num
<< 1 ) | *( src
+ ( numbits
-( i
+ 1 )));
150 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
151 uint8_t preambleSearch ( uint8_t * BitStream
, uint8_t * preamble
, size_t pLen
, size_t * size
, size_t * startIdx
)
153 // Sanity check. If preamble length is bigger than bitstream length.
154 if ( * size
<= pLen
) return 0 ;
157 for ( int idx
= 0 ; idx
< * size
- pLen
; idx
++){
158 if ( memcmp ( BitStream
+ idx
, preamble
, pLen
) == 0 ){
165 * size
= idx
- * startIdx
;
174 //takes 1s and 0s and searches for EM410x format - output EM ID
175 uint8_t Em410xDecode ( uint8_t * BitStream
, size_t * size
, size_t * startIdx
, uint32_t * hi
, uint64_t * lo
)
177 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
178 // otherwise could be a void with no arguments
181 if ( BitStream
[ 1 ]> 1 ) return 0 ; //allow only 1s and 0s
183 // 111111111 bit pattern represent start of frame
184 // include 0 in front to help get start pos
185 uint8_t preamble
[] = { 0 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 };
187 uint32_t parityBits
= 0 ;
191 errChk
= preambleSearch ( BitStream
, preamble
, sizeof ( preamble
), size
, startIdx
);
192 if ( errChk
== 0 || * size
< 64 ) return 0 ;
193 if (* size
> 64 ) FmtLen
= 22 ;
194 * startIdx
+= 1 ; //get rid of 0 from preamble
196 for ( i
= 0 ; i
< FmtLen
; i
++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
197 parityBits
= bytebits_to_byte ( BitStream
+( i
* 5 )+ idx
, 5 );
198 //check even parity - quit if failed
199 if ( parityTest ( parityBits
, 5 , 0 ) == 0 ) return 0 ;
200 //set uint64 with ID from BitStream
201 for ( uint8_t ii
= 0 ; ii
< 4 ; ii
++){
202 * hi
= (* hi
<< 1 ) | (* lo
>> 63 );
203 * lo
= (* lo
<< 1 ) | ( BitStream
[( i
* 5 )+ ii
+ idx
]);
206 if ( errChk
!= 0 ) return 1 ;
207 //skip last 5 bit parity test for simplicity.
213 //demodulates strong heavily clipped samples
214 int cleanAskRawDemod ( uint8_t * BinStream
, size_t * size
, int clk
, int invert
, int high
, int low
)
216 size_t bitCnt
= 0 , smplCnt
= 0 , errCnt
= 0 ;
217 uint8_t waveHigh
= 0 ;
218 for ( size_t i
= 0 ; i
< * size
; i
++){
219 if ( BinStream
[ i
] >= high
&& waveHigh
){
221 } else if ( BinStream
[ i
] <= low
&& ! waveHigh
){
223 } else { //transition
224 if (( BinStream
[ i
] >= high
&& ! waveHigh
) || ( BinStream
[ i
] <= low
&& waveHigh
)){
225 if ( smplCnt
> clk
-( clk
/ 4 )- 1 ) { //full clock
226 if ( smplCnt
> clk
+ ( clk
/ 4 )+ 1 ) { //too many samples
228 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Modulation Error at: %u" , i
);
229 BinStream
[ bitCnt
++]= 7 ;
230 } else if ( waveHigh
) {
231 BinStream
[ bitCnt
++] = invert
;
232 BinStream
[ bitCnt
++] = invert
;
233 } else if (! waveHigh
) {
234 BinStream
[ bitCnt
++] = invert
^ 1 ;
235 BinStream
[ bitCnt
++] = invert
^ 1 ;
239 } else if ( smplCnt
> ( clk
/ 2 ) - ( clk
/ 4 )- 1 ) {
241 BinStream
[ bitCnt
++] = invert
;
242 } else if (! waveHigh
) {
243 BinStream
[ bitCnt
++] = invert
^ 1 ;
247 } else if (! bitCnt
) {
249 waveHigh
= ( BinStream
[ i
] >= high
);
253 //transition bit oops
255 } else { //haven't hit new high or new low yet
265 void askAmp ( uint8_t * BitStream
, size_t size
)
268 for ( size_t i
= 1 ; i
< size
; i
++){
269 if ( BitStream
[ i
]- BitStream
[ i
- 1 ]>= 30 ) //large jump up
271 else if ( BitStream
[ i
- 1 ]- BitStream
[ i
]>= 20 ) //large jump down
274 BitStream
[ i
- 1 ] = Last
;
280 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
281 int askdemod ( uint8_t * BinStream
, size_t * size
, int * clk
, int * invert
, int maxErr
, uint8_t amp
, uint8_t askType
)
283 if (* size
== 0 ) return - 1 ;
284 int start
= DetectASKClock ( BinStream
, * size
, clk
, maxErr
); //clock default
285 if (* clk
== 0 || start
< 0 ) return - 3 ;
286 if (* invert
!= 1 ) * invert
= 0 ;
287 if ( amp
== 1 ) askAmp ( BinStream
, * size
);
288 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: clk %d, beststart %d, amp %d" , * clk
, start
, amp
);
290 uint8_t initLoopMax
= 255 ;
291 if ( initLoopMax
> * size
) initLoopMax
= * size
;
292 // Detect high and lows
293 //25% clip in case highs and lows aren't clipped [marshmellow]
295 if ( getHiLo ( BinStream
, initLoopMax
, & high
, & low
, 75 , 75 ) < 1 )
296 return - 2 ; //just noise
299 // if clean clipped waves detected run alternate demod
300 if ( DetectCleanAskWave ( BinStream
, * size
, high
, low
)) {
301 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Clean Wave Detected - using clean wave demod" );
302 errCnt
= cleanAskRawDemod ( BinStream
, size
, * clk
, * invert
, high
, low
);
303 if ( askType
) //askman
304 return manrawdecode ( BinStream
, size
, 0 );
308 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Weak Wave Detected - using weak wave demod" );
310 int lastBit
; //set first clock check - can go negative
311 size_t i
, bitnum
= 0 ; //output counter
313 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
314 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
315 size_t MaxBits
= 3072 ; //max bits to collect
316 lastBit
= start
- * clk
;
318 for ( i
= start
; i
< * size
; ++ i
) {
319 if ( i
- lastBit
>= * clk
- tol
){
320 if ( BinStream
[ i
] >= high
) {
321 BinStream
[ bitnum
++] = * invert
;
322 } else if ( BinStream
[ i
] <= low
) {
323 BinStream
[ bitnum
++] = * invert
^ 1 ;
324 } else if ( i
- lastBit
>= * clk
+ tol
) {
326 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Modulation Error at: %u" , i
);
327 BinStream
[ bitnum
++]= 7 ;
330 } else { //in tolerance - looking for peak
335 } else if ( i
- lastBit
>= (* clk
/ 2 - tol
) && ! midBit
&& ! askType
){
336 if ( BinStream
[ i
] >= high
) {
337 BinStream
[ bitnum
++] = * invert
;
338 } else if ( BinStream
[ i
] <= low
) {
339 BinStream
[ bitnum
++] = * invert
^ 1 ;
340 } else if ( i
- lastBit
>= * clk
/ 2 + tol
) {
341 BinStream
[ bitnum
] = BinStream
[ bitnum
- 1 ];
343 } else { //in tolerance - looking for peak
348 if ( bitnum
>= MaxBits
) break ;
355 //take 10 and 01 and manchester decode
356 //run through 2 times and take least errCnt
357 int manrawdecode ( uint8_t * BitStream
, size_t * size
, uint8_t invert
)
359 uint16_t bitnum
= 0 , MaxBits
= 512 , errCnt
= 0 ;
361 uint16_t bestErr
= 1000 , bestRun
= 0 ;
362 if (* size
< 16 ) return - 1 ;
363 //find correct start position [alignment]
364 for ( ii
= 0 ; ii
< 2 ;++ ii
){
365 for ( i
= ii
; i
<* size
- 3 ; i
+= 2 )
366 if ( BitStream
[ i
]== BitStream
[ i
+ 1 ])
376 for ( i
= bestRun
; i
< * size
- 3 ; i
+= 2 ){
377 if ( BitStream
[ i
] == 1 && ( BitStream
[ i
+ 1 ] == 0 )){
378 BitStream
[ bitnum
++]= invert
;
379 } else if (( BitStream
[ i
] == 0 ) && BitStream
[ i
+ 1 ] == 1 ){
380 BitStream
[ bitnum
++]= invert
^ 1 ;
382 BitStream
[ bitnum
++]= 7 ;
384 if ( bitnum
> MaxBits
) break ;
390 uint32_t manchesterEncode2Bytes ( uint16_t datain
) {
393 for ( uint8_t i
= 0 ; i
< 16 ; i
++) {
394 curBit
= ( datain
>> ( 15 - i
) & 1 );
395 output
|= ( 1 <<((( 15 - i
)* 2 )+ curBit
));
401 //encode binary data into binary manchester
402 int ManchesterEncode ( uint8_t * BitStream
, size_t size
)
404 size_t modIdx
= 20000 , i
= 0 ;
405 if ( size
> modIdx
) return - 1 ;
406 for ( size_t idx
= 0 ; idx
< size
; idx
++){
407 BitStream
[ idx
+ modIdx
++] = BitStream
[ idx
];
408 BitStream
[ idx
+ modIdx
++] = BitStream
[ idx
]^ 1 ;
410 for (; i
<( size
* 2 ); i
++){
411 BitStream
[ i
] = BitStream
[ i
+ 20000 ];
417 //take 01 or 10 = 1 and 11 or 00 = 0
418 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
419 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
420 int BiphaseRawDecode ( uint8_t * BitStream
, size_t * size
, int offset
, int invert
)
425 uint16_t MaxBits
= 512 ;
426 //if not enough samples - error
427 if (* size
< 51 ) return - 1 ;
428 //check for phase change faults - skip one sample if faulty
429 uint8_t offsetA
= 1 , offsetB
= 1 ;
431 if ( BitStream
[ i
+ 1 ]== BitStream
[ i
+ 2 ]) offsetA
= 0 ;
432 if ( BitStream
[ i
+ 2 ]== BitStream
[ i
+ 3 ]) offsetB
= 0 ;
434 if (! offsetA
&& offsetB
) offset
++;
435 for ( i
= offset
; i
<* size
- 3 ; i
+= 2 ){
436 //check for phase error
437 if ( BitStream
[ i
+ 1 ]== BitStream
[ i
+ 2 ]) {
438 BitStream
[ bitnum
++]= 7 ;
441 if (( BitStream
[ i
]== 1 && BitStream
[ i
+ 1 ]== 0 ) || ( BitStream
[ i
]== 0 && BitStream
[ i
+ 1 ]== 1 )){
442 BitStream
[ bitnum
++]= 1 ^ invert
;
443 } else if (( BitStream
[ i
]== 0 && BitStream
[ i
+ 1 ]== 0 ) || ( BitStream
[ i
]== 1 && BitStream
[ i
+ 1 ]== 1 )){
444 BitStream
[ bitnum
++]= invert
;
446 BitStream
[ bitnum
++]= 7 ;
449 if ( bitnum
> MaxBits
) break ;
456 // demod gProxIIDemod
457 // error returns as -x
458 // success returns start position in BitStream
459 // BitStream must contain previously askrawdemod and biphasedemoded data
460 int gProxII_Demod ( uint8_t BitStream
[], size_t * size
)
463 uint8_t preamble
[] = { 1 , 1 , 1 , 1 , 1 , 0 };
465 uint8_t errChk
= preambleSearch ( BitStream
, preamble
, sizeof ( preamble
), size
, & startIdx
);
466 if ( errChk
== 0 ) return - 3 ; //preamble not found
467 if (* size
!= 96 ) return - 2 ; //should have found 96 bits
468 //check first 6 spacer bits to verify format
469 if (! BitStream
[ startIdx
+ 5 ] && ! BitStream
[ startIdx
+ 10 ] && ! BitStream
[ startIdx
+ 15 ] && ! BitStream
[ startIdx
+ 20 ] && ! BitStream
[ startIdx
+ 25 ] && ! BitStream
[ startIdx
+ 30 ]){
470 //confirmed proper separator bits found
471 //return start position
472 return ( int ) startIdx
;
474 return - 5 ; //spacer bits not found - not a valid gproxII
477 //translate wave to 11111100000 (1 for each short wave [higher freq] 0 for each long wave [lower freq])
478 size_t fsk_wave_demod ( uint8_t * dest
, size_t size
, uint8_t fchigh
, uint8_t fclow
)
480 size_t last_transition
= 0 ;
483 if ( fchigh
== 0 ) fchigh
= 10 ;
484 if ( fclow
== 0 ) fclow
= 8 ;
485 //set the threshold close to 0 (graph) or 128 std to avoid static
486 uint8_t threshold_value
= 123 ;
487 size_t preLastSample
= 0 ;
488 size_t LastSample
= 0 ;
489 size_t currSample
= 0 ;
490 if ( size
< 1024 ) return 0 ; // not enough samples
492 // jump to modulating data by finding the first 4 threshold crossings (or first 2 waves)
493 // in case you have junk or noise at the beginning of the trace...
494 uint8_t thresholdCnt
= 0 ;
495 size_t waveSizeCnt
= 0 ;
496 bool isAboveThreshold
= dest
[ idx
] >= threshold_value
;
497 for (; idx
< size
- 20 ; idx
++ ) {
498 if ( dest
[ idx
] < threshold_value
&& isAboveThreshold
) {
500 if ( thresholdCnt
> 4 && waveSizeCnt
< fchigh
+ 1 ) break ;
501 isAboveThreshold
= false ;
503 } else if ( dest
[ idx
] >= threshold_value
&& ! isAboveThreshold
) {
505 if ( thresholdCnt
> 4 && waveSizeCnt
< fchigh
+ 1 ) break ;
506 isAboveThreshold
= true ;
511 if ( thresholdCnt
> 10 ) break ;
513 if ( g_debugMode
== 2 ) prnt ( "threshold Count reached at %u" , idx
);
515 // Need to threshold first sample
516 if ( dest
[ idx
] < threshold_value
) dest
[ 0 ] = 0 ;
521 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
522 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
523 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
524 // (could also be fc/5 && fc/7 for fsk1 = 4-9)
525 for (; idx
< size
- 20 ; idx
++) {
526 // threshold current value
528 if ( dest
[ idx
] < threshold_value
) dest
[ idx
] = 0 ;
531 // Check for 0->1 transition
532 if ( dest
[ idx
- 1 ] < dest
[ idx
]) {
533 preLastSample
= LastSample
;
534 LastSample
= currSample
;
535 currSample
= idx
- last_transition
;
536 if ( currSample
< ( fclow
- 2 )) { //0-5 = garbage noise (or 0-3)
537 //do nothing with extra garbage
538 } else if ( currSample
< ( fchigh
- 1 )) { //6-8 = 8 sample waves (or 3-6 = 5)
539 //correct previous 9 wave surrounded by 8 waves (or 6 surrounded by 5)
540 if ( LastSample
> ( fchigh
- 2 ) && ( preLastSample
< ( fchigh
- 1 ))){
545 } else if ( currSample
> ( fchigh
+ 1 ) && numBits
< 3 ) { //12 + and first two bit = unusable garbage
546 //do nothing with beginning garbage and reset.. should be rare..
548 } 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)
550 } else { //9+ = 10 sample waves (or 6+ = 7)
553 last_transition
= idx
;
556 return numBits
; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
559 //translate 11111100000 to 10
560 //rfLen = clock, fchigh = larger field clock, fclow = smaller field clock
561 size_t aggregate_bits ( uint8_t * dest
, size_t size
, uint8_t rfLen
,
562 uint8_t invert
, uint8_t fchigh
, uint8_t fclow
)
564 uint8_t lastval
= dest
[ 0 ];
568 for ( idx
= 1 ; idx
< size
; idx
++) {
570 if ( dest
[ idx
]== lastval
) continue ; //skip until we hit a transition
572 //find out how many bits (n) we collected
573 //if lastval was 1, we have a 1->0 crossing
574 if ( dest
[ idx
- 1 ]== 1 ) {
575 n
= ( n
* fclow
+ rfLen
/ 2 ) / rfLen
;
576 } else { // 0->1 crossing
577 n
= ( n
* fchigh
+ rfLen
/ 2 ) / rfLen
;
581 //add to our destination the bits we collected
582 memset ( dest
+ numBits
, dest
[ idx
- 1 ]^ invert
, n
);
587 // if valid extra bits at the end were all the same frequency - add them in
588 if ( n
> rfLen
/ fchigh
) {
589 if ( dest
[ idx
- 2 ]== 1 ) {
590 n
= ( n
* fclow
+ rfLen
/ 2 ) / rfLen
;
592 n
= ( n
* fchigh
+ rfLen
/ 2 ) / rfLen
;
594 memset ( dest
+ numBits
, dest
[ idx
- 1 ]^ invert
, n
);
600 //by marshmellow (from holiman's base)
601 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
602 int fskdemod ( uint8_t * dest
, size_t size
, uint8_t rfLen
, uint8_t invert
, uint8_t fchigh
, uint8_t fclow
)
605 size
= fsk_wave_demod ( dest
, size
, fchigh
, fclow
);
606 size
= aggregate_bits ( dest
, size
, rfLen
, invert
, fchigh
, fclow
);
610 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
611 int HIDdemodFSK ( uint8_t * dest
, size_t * size
, uint32_t * hi2
, uint32_t * hi
, uint32_t * lo
)
613 if ( justNoise ( dest
, * size
)) return - 1 ;
615 size_t numStart
= 0 , size2
=* size
, startIdx
= 0 ;
617 * size
= fskdemod ( dest
, size2
, 50 , 1 , 10 , 8 ); //fsk2a
618 if (* size
< 96 * 2 ) return - 2 ;
619 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
620 uint8_t preamble
[] = { 0 , 0 , 0 , 1 , 1 , 1 , 0 , 1 };
621 // find bitstring in array
622 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
623 if ( errChk
== 0 ) return - 3 ; //preamble not found
625 numStart
= startIdx
+ sizeof ( preamble
);
626 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
627 for ( size_t idx
= numStart
; ( idx
- numStart
) < * size
- sizeof ( preamble
); idx
+= 2 ){
628 if ( dest
[ idx
] == dest
[ idx
+ 1 ]){
629 return - 4 ; //not manchester data
631 * hi2
= (* hi2
<< 1 )|(* hi
>> 31 );
632 * hi
= (* hi
<< 1 )|(* lo
>> 31 );
633 //Then, shift in a 0 or one into low
634 if ( dest
[ idx
] && ! dest
[ idx
+ 1 ]) // 1 0
639 return ( int ) startIdx
;
642 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
643 int ParadoxdemodFSK ( uint8_t * dest
, size_t * size
, uint32_t * hi2
, uint32_t * hi
, uint32_t * lo
)
645 if ( justNoise ( dest
, * size
)) return - 1 ;
647 size_t numStart
= 0 , size2
=* size
, startIdx
= 0 ;
649 * size
= fskdemod ( dest
, size2
, 50 , 1 , 10 , 8 ); //fsk2a
650 if (* size
< 96 ) return - 2 ;
652 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
653 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 1 , 1 , 1 , 1 };
655 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
656 if ( errChk
== 0 ) return - 3 ; //preamble not found
658 numStart
= startIdx
+ sizeof ( preamble
);
659 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
660 for ( size_t idx
= numStart
; ( idx
- numStart
) < * size
- sizeof ( preamble
); idx
+= 2 ){
661 if ( dest
[ idx
] == dest
[ idx
+ 1 ])
662 return - 4 ; //not manchester data
663 * hi2
= (* hi2
<< 1 )|(* hi
>> 31 );
664 * hi
= (* hi
<< 1 )|(* lo
>> 31 );
665 //Then, shift in a 0 or one into low
666 if ( dest
[ idx
] && ! dest
[ idx
+ 1 ]) // 1 0
671 return ( int ) startIdx
;
674 int IOdemodFSK ( uint8_t * dest
, size_t size
)
676 if ( justNoise ( dest
, size
)) return - 1 ;
677 //make sure buffer has data
678 if ( size
< 66 * 64 ) return - 2 ;
680 size
= fskdemod ( dest
, size
, 64 , 1 , 10 , 8 ); // FSK2a RF/64
681 if ( size
< 65 ) return - 3 ; //did we get a good demod?
683 //0 10 20 30 40 50 60
685 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
686 //-----------------------------------------------------------------------------
687 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
689 //XSF(version)facility:codeone+codetwo
692 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
693 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), & size
, & startIdx
);
694 if ( errChk
== 0 ) return - 4 ; //preamble not found
696 if (! dest
[ startIdx
+ 8 ] && dest
[ startIdx
+ 17 ]== 1 && dest
[ startIdx
+ 26 ]== 1 && dest
[ startIdx
+ 35 ]== 1 && dest
[ startIdx
+ 44 ]== 1 && dest
[ startIdx
+ 53 ]== 1 ){
697 //confirmed proper separator bits found
698 //return start position
699 return ( int ) startIdx
;
705 // find viking preamble 0xF200 in already demoded data
706 int VikingDemod_AM ( uint8_t * dest
, size_t * size
) {
707 //make sure buffer has data
708 if (* size
< 64 * 2 ) return - 2 ;
711 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 };
712 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
713 if ( errChk
== 0 ) return - 4 ; //preamble not found
714 uint32_t checkCalc
= bytebits_to_byte ( dest
+ startIdx
, 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 8 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 16 , 8 )
715 ^ bytebits_to_byte ( dest
+ startIdx
+ 24 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 32 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 40 , 8 )
716 ^ bytebits_to_byte ( dest
+ startIdx
+ 48 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 56 , 8 );
717 if ( checkCalc
!= 0xA8 ) return - 5 ;
718 if (* size
!= 64 ) return - 6 ;
719 //return start position
720 return ( int ) startIdx
;
723 // find presco preamble 0x10D in already demoded data
724 int PrescoDemod ( uint8_t * dest
, size_t * size
) {
725 //make sure buffer has data
726 if (* size
< 64 * 2 ) return - 2 ;
729 uint8_t preamble
[] = { 1 , 0 , 0 , 0 , 0 , 1 , 1 , 0 , 1 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
730 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
731 if ( errChk
== 0 ) return - 4 ; //preamble not found
732 //return start position
733 return ( int ) startIdx
;
736 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
737 // BitStream must contain previously askrawdemod and biphasedemoded data
738 int FDXBdemodBI ( uint8_t * dest
, size_t * size
)
740 //make sure buffer has enough data
741 if (* size
< 128 ) return - 1 ;
744 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
746 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
747 if ( errChk
== 0 ) return - 2 ; //preamble not found
748 return ( int ) startIdx
;
752 // FSK Demod then try to locate an AWID ID
753 int AWIDdemodFSK ( uint8_t * dest
, size_t * size
)
755 //make sure buffer has enough data
756 if (* size
< 96 * 50 ) return - 1 ;
758 if ( justNoise ( dest
, * size
)) return - 2 ;
761 * size
= fskdemod ( dest
, * size
, 50 , 1 , 10 , 8 ); // fsk2a RF/50
762 if (* size
< 96 ) return - 3 ; //did we get a good demod?
764 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
766 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
767 if ( errChk
== 0 ) return - 4 ; //preamble not found
768 if (* size
!= 96 ) return - 5 ;
769 return ( int ) startIdx
;
773 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
774 int PyramiddemodFSK ( uint8_t * dest
, size_t * size
)
776 //make sure buffer has data
777 if (* size
< 128 * 50 ) return - 5 ;
779 //test samples are not just noise
780 if ( justNoise ( dest
, * size
)) return - 1 ;
783 * size
= fskdemod ( dest
, * size
, 50 , 1 , 10 , 8 ); // fsk2a RF/50
784 if (* size
< 128 ) return - 2 ; //did we get a good demod?
786 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
788 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
789 if ( errChk
== 0 ) return - 4 ; //preamble not found
790 if (* size
!= 128 ) return - 3 ;
791 return ( int ) startIdx
;
795 // to detect a wave that has heavily clipped (clean) samples
796 uint8_t DetectCleanAskWave ( uint8_t dest
[], size_t size
, uint8_t high
, uint8_t low
)
798 bool allArePeaks
= true ;
800 size_t loopEnd
= 512 + 160 ;
801 if ( loopEnd
> size
) loopEnd
= size
;
802 for ( size_t i
= 160 ; i
< loopEnd
; i
++){
803 if ( dest
[ i
]> low
&& dest
[ i
]< high
)
809 if ( cntPeaks
> 300 ) return true ;
814 // to help detect clocks on heavily clipped samples
815 // based on count of low to low
816 int DetectStrongAskClock ( uint8_t dest
[], size_t size
, uint8_t high
, uint8_t low
)
818 uint8_t fndClk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 128 };
822 // get to first full low to prime loop and skip incomplete first pulse
823 while (( dest
[ i
] < high
) && ( i
< size
))
825 while (( dest
[ i
] > low
) && ( i
< size
))
828 // loop through all samples
830 // measure from low to low
831 while (( dest
[ i
] > low
) && ( i
< size
))
834 while (( dest
[ i
] < high
) && ( i
< size
))
836 while (( dest
[ i
] > low
) && ( i
< size
))
838 //get minimum measured distance
839 if ( i
- startwave
< minClk
&& i
< size
)
840 minClk
= i
- startwave
;
843 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: detectstrongASKclk smallest wave: %d" , minClk
);
844 for ( uint8_t clkCnt
= 0 ; clkCnt
< 7 ; clkCnt
++) {
845 if ( minClk
>= fndClk
[ clkCnt
]-( fndClk
[ clkCnt
]/ 8 ) && minClk
<= fndClk
[ clkCnt
]+ 1 )
846 return fndClk
[ clkCnt
];
852 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
853 // maybe somehow adjust peak trimming value based on samples to fix?
854 // return start index of best starting position for that clock and return clock (by reference)
855 int DetectASKClock ( uint8_t dest
[], size_t size
, int * clock
, int maxErr
)
858 uint8_t clk
[] = { 255 , 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 };
860 uint8_t loopCnt
= 255 ; //don't need to loop through entire array...
861 if ( size
<= loopCnt
+ 60 ) return - 1 ; //not enough samples
862 size
-= 60 ; //sometimes there is a strange end wave - filter out this....
863 //if we already have a valid clock
866 if ( clk
[ i
] == * clock
) clockFnd
= i
;
867 //clock found but continue to find best startpos
869 //get high and low peak
871 if ( getHiLo ( dest
, loopCnt
, & peak
, & low
, 75 , 75 ) < 1 ) return - 1 ;
873 //test for large clean peaks
875 if ( DetectCleanAskWave ( dest
, size
, peak
, low
)== 1 ){
876 int ans
= DetectStrongAskClock ( dest
, size
, peak
, low
);
877 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d" , ans
);
878 for ( i
= clkEnd
- 1 ; i
> 0 ; i
--){
882 return 0 ; // for strong waves i don't use the 'best start position' yet...
883 //break; //clock found but continue to find best startpos [not yet]
889 uint8_t clkCnt
, tol
= 0 ;
890 uint16_t bestErr
[]={ 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 };
891 uint8_t bestStart
[]={ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
893 size_t arrLoc
, loopEnd
;
901 //test each valid clock from smallest to greatest to see which lines up
902 for (; clkCnt
< clkEnd
; clkCnt
++){
903 if ( clk
[ clkCnt
] <= 32 ){
908 //if no errors allowed - keep start within the first clock
909 if (! maxErr
&& size
> clk
[ clkCnt
]* 2 + tol
&& clk
[ clkCnt
]< 128 ) loopCnt
= clk
[ clkCnt
]* 2 ;
910 bestErr
[ clkCnt
]= 1000 ;
911 //try lining up the peaks by moving starting point (try first few clocks)
912 for ( ii
= 0 ; ii
< loopCnt
; ii
++){
913 if ( dest
[ ii
] < peak
&& dest
[ ii
] > low
) continue ;
916 // now that we have the first one lined up test rest of wave array
917 loopEnd
= (( size
- ii
- tol
) / clk
[ clkCnt
]) - 1 ;
918 for ( i
= 0 ; i
< loopEnd
; ++ i
){
919 arrLoc
= ii
+ ( i
* clk
[ clkCnt
]);
920 if ( dest
[ arrLoc
] >= peak
|| dest
[ arrLoc
] <= low
){
921 } else if ( dest
[ arrLoc
- tol
] >= peak
|| dest
[ arrLoc
- tol
] <= low
){
922 } else if ( dest
[ arrLoc
+ tol
] >= peak
|| dest
[ arrLoc
+ tol
] <= low
){
923 } else { //error no peak detected
927 //if we found no errors then we can stop here and a low clock (common clocks)
928 // this is correct one - return this clock
929 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: clk %d, err %d, startpos %d, endpos %d" , clk
[ clkCnt
], errCnt
, ii
, i
);
930 if ( errCnt
== 0 && clkCnt
< 7 ) {
931 if (! clockFnd
) * clock
= clk
[ clkCnt
];
934 //if we found errors see if it is lowest so far and save it as best run
935 if ( errCnt
< bestErr
[ clkCnt
]){
936 bestErr
[ clkCnt
]= errCnt
;
937 bestStart
[ clkCnt
]= ii
;
943 for ( iii
= 1 ; iii
< clkEnd
; ++ iii
){
944 if ( bestErr
[ iii
] < bestErr
[ best
]){
945 if ( bestErr
[ iii
] == 0 ) bestErr
[ iii
]= 1 ;
946 // current best bit to error ratio vs new bit to error ratio
947 if ( ( size
/ clk
[ best
])/ bestErr
[ best
] < ( size
/ clk
[ iii
])/ bestErr
[ iii
] ){
951 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
]);
953 if (! clockFnd
) * clock
= clk
[ best
];
954 return bestStart
[ best
];
958 //detect psk clock by reading each phase shift
959 // a phase shift is determined by measuring the sample length of each wave
960 int DetectPSKClock ( uint8_t dest
[], size_t size
, int clock
)
962 uint8_t clk
[]={ 255 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 }; //255 is not a valid clock
963 uint16_t loopCnt
= 4096 ; //don't need to loop through entire array...
964 if ( size
== 0 ) return 0 ;
965 if ( size
< loopCnt
) loopCnt
= size
- 20 ;
967 //if we already have a valid clock quit
970 if ( clk
[ i
] == clock
) return clock
;
972 size_t waveStart
= 0 , waveEnd
= 0 , firstFullWave
= 0 , lastClkBit
= 0 ;
973 uint8_t clkCnt
, fc
= 0 , fullWaveLen
= 0 , tol
= 1 ;
974 uint16_t peakcnt
= 0 , errCnt
= 0 , waveLenCnt
= 0 ;
975 uint16_t bestErr
[]={ 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 };
976 uint16_t peaksdet
[]={ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
977 fc
= countFC ( dest
, size
, 0 );
978 if ( fc
!= 2 && fc
!= 4 && fc
!= 8 ) return - 1 ;
979 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: FC: %d" , fc
);
981 //find first full wave
982 for ( i
= 160 ; i
< loopCnt
; i
++){
983 if ( dest
[ i
] < dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
984 if ( waveStart
== 0 ) {
986 //prnt("DEBUG: waveStart: %d",waveStart);
989 //prnt("DEBUG: waveEnd: %d",waveEnd);
990 waveLenCnt
= waveEnd
- waveStart
;
991 if ( waveLenCnt
> fc
){
992 firstFullWave
= waveStart
;
993 fullWaveLen
= waveLenCnt
;
1000 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: firstFullWave: %d, waveLen: %d" , firstFullWave
, fullWaveLen
);
1002 //test each valid clock from greatest to smallest to see which lines up
1003 for ( clkCnt
= 7 ; clkCnt
>= 1 ; clkCnt
--){
1004 lastClkBit
= firstFullWave
; //set end of wave as clock align
1008 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: clk: %d, lastClkBit: %d" , clk
[ clkCnt
], lastClkBit
);
1010 for ( i
= firstFullWave
+ fullWaveLen
- 1 ; i
< loopCnt
- 2 ; i
++){
1011 //top edge of wave = start of new wave
1012 if ( dest
[ i
] < dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1013 if ( waveStart
== 0 ) {
1018 waveLenCnt
= waveEnd
- waveStart
;
1019 if ( waveLenCnt
> fc
){
1020 //if this wave is a phase shift
1021 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
);
1022 if ( i
+ 1 >= lastClkBit
+ clk
[ clkCnt
] - tol
){ //should be a clock bit
1024 lastClkBit
+= clk
[ clkCnt
];
1025 } else if ( i
< lastClkBit
+ 8 ){
1026 //noise after a phase shift - ignore
1027 } else { //phase shift before supposed to based on clock
1030 } else if ( i
+ 1 > lastClkBit
+ clk
[ clkCnt
] + tol
+ fc
){
1031 lastClkBit
+= clk
[ clkCnt
]; //no phase shift but clock bit
1040 if ( errCnt
<= bestErr
[ clkCnt
]) bestErr
[ clkCnt
]= errCnt
;
1041 if ( peakcnt
> peaksdet
[ clkCnt
]) peaksdet
[ clkCnt
]= peakcnt
;
1043 //all tested with errors
1044 //return the highest clk with the most peaks found
1046 for ( i
= 7 ; i
>= 1 ; i
--){
1047 if ( peaksdet
[ i
] > peaksdet
[ best
]) {
1050 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d" , clk
[ i
], peaksdet
[ i
], bestErr
[ i
], clk
[ best
]);
1055 int DetectStrongNRZClk ( uint8_t * dest
, size_t size
, int peak
, int low
){
1056 //find shortest transition from high to low
1058 size_t transition1
= 0 ;
1059 int lowestTransition
= 255 ;
1060 bool lastWasHigh
= false ;
1062 //find first valid beginning of a high or low wave
1063 while (( dest
[ i
] >= peak
|| dest
[ i
] <= low
) && ( i
< size
))
1065 while (( dest
[ i
] < peak
&& dest
[ i
] > low
) && ( i
< size
))
1067 lastWasHigh
= ( dest
[ i
] >= peak
);
1069 if ( i
== size
) return 0 ;
1072 for (; i
< size
; i
++) {
1073 if (( dest
[ i
] >= peak
&& ! lastWasHigh
) || ( dest
[ i
] <= low
&& lastWasHigh
)) {
1074 lastWasHigh
= ( dest
[ i
] >= peak
);
1075 if ( i
- transition1
< lowestTransition
) lowestTransition
= i
- transition1
;
1079 if ( lowestTransition
== 255 ) lowestTransition
= 0 ;
1080 if ( g_debugMode
== 2 ) prnt ( "DEBUG NRZ: detectstrongNRZclk smallest wave: %d" , lowestTransition
);
1081 return lowestTransition
;
1085 //detect nrz clock by reading #peaks vs no peaks(or errors)
1086 int DetectNRZClock ( uint8_t dest
[], size_t size
, int clock
)
1089 uint8_t clk
[]={ 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 };
1090 size_t loopCnt
= 4096 ; //don't need to loop through entire array...
1091 if ( size
== 0 ) return 0 ;
1092 if ( size
< loopCnt
) loopCnt
= size
- 20 ;
1093 //if we already have a valid clock quit
1095 if ( clk
[ i
] == clock
) return clock
;
1097 //get high and low peak
1099 if ( getHiLo ( dest
, loopCnt
, & peak
, & low
, 75 , 75 ) < 1 ) return 0 ;
1101 int lowestTransition
= DetectStrongNRZClk ( dest
, size
- 20 , peak
, low
);
1105 uint16_t smplCnt
= 0 ;
1106 int16_t peakcnt
= 0 ;
1107 int16_t peaksdet
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1108 uint16_t maxPeak
= 255 ;
1109 bool firstpeak
= false ;
1110 //test for large clipped waves
1111 for ( i
= 0 ; i
< loopCnt
; i
++){
1112 if ( dest
[ i
] >= peak
|| dest
[ i
] <= low
){
1113 if (! firstpeak
) continue ;
1118 if ( maxPeak
> smplCnt
){
1120 //prnt("maxPk: %d",maxPeak);
1123 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1128 bool errBitHigh
= 0 ;
1130 uint8_t ignoreCnt
= 0 ;
1131 uint8_t ignoreWindow
= 4 ;
1132 bool lastPeakHigh
= 0 ;
1135 //test each valid clock from smallest to greatest to see which lines up
1136 for ( clkCnt
= 0 ; clkCnt
< 8 ; ++ clkCnt
){
1137 //ignore clocks smaller than smallest peak
1138 if ( clk
[ clkCnt
] < maxPeak
- ( clk
[ clkCnt
]/ 4 )) continue ;
1139 //try lining up the peaks by moving starting point (try first 256)
1140 for ( ii
= 20 ; ii
< loopCnt
; ++ ii
){
1141 if (( dest
[ ii
] >= peak
) || ( dest
[ ii
] <= low
)){
1145 lastBit
= ii
- clk
[ clkCnt
];
1146 //loop through to see if this start location works
1147 for ( i
= ii
; i
< size
- 20 ; ++ i
) {
1148 //if we are at a clock bit
1149 if (( i
>= lastBit
+ clk
[ clkCnt
] - tol
) && ( i
<= lastBit
+ clk
[ clkCnt
] + tol
)) {
1151 if ( dest
[ i
] >= peak
|| dest
[ i
] <= low
) {
1152 //if same peak don't count it
1153 if (( dest
[ i
] >= peak
&& ! lastPeakHigh
) || ( dest
[ i
] <= low
&& lastPeakHigh
)) {
1156 lastPeakHigh
= ( dest
[ i
] >= peak
);
1159 ignoreCnt
= ignoreWindow
;
1160 lastBit
+= clk
[ clkCnt
];
1161 } else if ( i
== lastBit
+ clk
[ clkCnt
] + tol
) {
1162 lastBit
+= clk
[ clkCnt
];
1164 //else if not a clock bit and no peaks
1165 } else if ( dest
[ i
] < peak
&& dest
[ i
] > low
){
1168 if ( errBitHigh
== true ) peakcnt
--;
1173 // else if not a clock bit but we have a peak
1174 } else if (( dest
[ i
]>= peak
|| dest
[ i
]<= low
) && (! bitHigh
)) {
1175 //error bar found no clock...
1179 if ( peakcnt
> peaksdet
[ clkCnt
]) {
1180 peaksdet
[ clkCnt
]= peakcnt
;
1187 for ( iii
= 7 ; iii
> 0 ; iii
--){
1188 if (( peaksdet
[ iii
] >= ( peaksdet
[ best
]- 1 )) && ( peaksdet
[ iii
] <= peaksdet
[ best
]+ 1 ) && lowestTransition
) {
1189 if ( clk
[ iii
] > ( lowestTransition
- ( clk
[ iii
]/ 8 )) && clk
[ iii
] < ( lowestTransition
+ ( clk
[ iii
]/ 8 ))) {
1192 } else if ( peaksdet
[ iii
] > peaksdet
[ best
]){
1195 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
);
1202 // convert psk1 demod to psk2 demod
1203 // only transition waves are 1s
1204 void psk1TOpsk2 ( uint8_t * BitStream
, size_t size
)
1207 uint8_t lastBit
= BitStream
[ 0 ];
1208 for (; i
< size
; i
++){
1209 if ( BitStream
[ i
]== 7 ){
1211 } else if ( lastBit
!= BitStream
[ i
]){
1212 lastBit
= BitStream
[ i
];
1222 // convert psk2 demod to psk1 demod
1223 // from only transition waves are 1s to phase shifts change bit
1224 void psk2TOpsk1 ( uint8_t * BitStream
, size_t size
)
1227 for ( size_t i
= 0 ; i
< size
; i
++){
1228 if ( BitStream
[ i
]== 1 ){
1236 // redesigned by marshmellow adjusted from existing decode functions
1237 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1238 int indala26decode ( uint8_t * bitStream
, size_t * size
, uint8_t * invert
)
1240 //26 bit 40134 format (don't know other formats)
1241 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 };
1242 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 };
1243 size_t startidx
= 0 ;
1244 if (! preambleSearch ( bitStream
, preamble
, sizeof ( preamble
), size
, & startidx
)){
1245 // if didn't find preamble try again inverting
1246 if (! preambleSearch ( bitStream
, preamble_i
, sizeof ( preamble_i
), size
, & startidx
)) return - 1 ;
1249 if (* size
!= 64 && * size
!= 224 ) return - 2 ;
1251 for ( size_t i
= startidx
; i
< * size
; i
++)
1254 return ( int ) startidx
;
1257 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1258 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1259 int nrzRawDemod ( uint8_t * dest
, size_t * size
, int * clk
, int * invert
){
1260 if ( justNoise ( dest
, * size
)) return - 1 ;
1261 * clk
= DetectNRZClock ( dest
, * size
, * clk
);
1262 if (* clk
== 0 ) return - 2 ;
1263 size_t i
, gLen
= 4096 ;
1264 if ( gLen
>* size
) gLen
= * size
- 20 ;
1266 if ( getHiLo ( dest
, gLen
, & high
, & low
, 75 , 75 ) < 1 ) return - 3 ; //25% fuzz on high 25% fuzz on low
1269 //convert wave samples to 1's and 0's
1270 for ( i
= 20 ; i
< * size
- 20 ; i
++){
1271 if ( dest
[ i
] >= high
) bit
= 1 ;
1272 if ( dest
[ i
] <= low
) bit
= 0 ;
1275 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1278 for ( i
= 21 ; i
< * size
- 20 ; i
++) {
1279 //if transition detected or large number of same bits - store the passed bits
1280 if ( dest
[ i
] != dest
[ i
- 1 ] || ( i
- lastBit
) == ( 10 * * clk
)) {
1281 memset ( dest
+ numBits
, dest
[ i
- 1 ] ^ * invert
, ( i
- lastBit
+ (* clk
/ 4 )) / * clk
);
1282 numBits
+= ( i
- lastBit
+ (* clk
/ 4 )) / * clk
;
1291 //detects the bit clock for FSK given the high and low Field Clocks
1292 uint8_t detectFSKClk ( uint8_t * BitStream
, size_t size
, uint8_t fcHigh
, uint8_t fcLow
)
1294 uint8_t clk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 0 };
1295 uint16_t rfLens
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1296 uint8_t rfCnts
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1297 uint8_t rfLensFnd
= 0 ;
1298 uint8_t lastFCcnt
= 0 ;
1299 uint16_t fcCounter
= 0 ;
1300 uint16_t rfCounter
= 0 ;
1301 uint8_t firstBitFnd
= 0 ;
1303 if ( size
== 0 ) return 0 ;
1305 uint8_t fcTol
= (( fcHigh
* 100 - fcLow
* 100 )/ 2 + 50 )/ 100 ; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1310 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
1311 // prime i to first peak / up transition
1312 for ( i
= 160 ; i
< size
- 20 ; i
++)
1313 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
]>= BitStream
[ i
+ 1 ])
1316 for (; i
< size
- 20 ; i
++){
1320 if ( BitStream
[ i
] <= BitStream
[ i
- 1 ] || BitStream
[ i
] < BitStream
[ i
+ 1 ])
1323 // if we got less than the small fc + tolerance then set it to the small fc
1324 if ( fcCounter
< fcLow
+ fcTol
)
1326 else //set it to the large fc
1329 //look for bit clock (rf/xx)
1330 if (( fcCounter
< lastFCcnt
|| fcCounter
> lastFCcnt
)){
1331 //not the same size as the last wave - start of new bit sequence
1332 if ( firstBitFnd
> 1 ){ //skip first wave change - probably not a complete bit
1333 for ( int ii
= 0 ; ii
< 15 ; ii
++){
1334 if ( rfLens
[ ii
] >= ( rfCounter
- 4 ) && rfLens
[ ii
] <= ( rfCounter
+ 4 )){
1340 if ( rfCounter
> 0 && rfLensFnd
< 15 ){
1341 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1342 rfCnts
[ rfLensFnd
]++;
1343 rfLens
[ rfLensFnd
++] = rfCounter
;
1349 lastFCcnt
= fcCounter
;
1353 uint8_t rfHighest
= 15 , rfHighest2
= 15 , rfHighest3
= 15 ;
1355 for ( i
= 0 ; i
< 15 ; i
++){
1356 //get highest 2 RF values (might need to get more values to compare or compare all?)
1357 if ( rfCnts
[ i
]> rfCnts
[ rfHighest
]){
1358 rfHighest3
= rfHighest2
;
1359 rfHighest2
= rfHighest
;
1361 } else if ( rfCnts
[ i
]> rfCnts
[ rfHighest2
]){
1362 rfHighest3
= rfHighest2
;
1364 } else if ( rfCnts
[ i
]> rfCnts
[ rfHighest3
]){
1367 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: RF %d, cnts %d" , rfLens
[ i
], rfCnts
[ i
]);
1369 // set allowed clock remainder tolerance to be 1 large field clock length+1
1370 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1371 uint8_t tol1
= fcHigh
+ 1 ;
1373 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d" , rfLens
[ rfHighest
], rfLens
[ rfHighest2
], rfLens
[ rfHighest3
]);
1375 // loop to find the highest clock that has a remainder less than the tolerance
1376 // compare samples counted divided by
1377 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1379 for (; ii
>= 2 ; ii
--){
1380 if ( rfLens
[ rfHighest
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1381 if ( rfLens
[ rfHighest2
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest2
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1382 if ( rfLens
[ rfHighest3
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest3
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1383 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: clk %d divides into the 3 most rf values within tolerance" , clk
[ ii
]);
1390 if ( ii
< 0 ) return 0 ; // oops we went too far
1396 //countFC is to detect the field clock lengths.
1397 //counts and returns the 2 most common wave lengths
1398 //mainly used for FSK field clock detection
1399 uint16_t countFC ( uint8_t * BitStream
, size_t size
, uint8_t fskAdj
)
1401 uint8_t fcLens
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1402 uint16_t fcCnts
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1403 uint8_t fcLensFnd
= 0 ;
1404 uint8_t lastFCcnt
= 0 ;
1405 uint8_t fcCounter
= 0 ;
1407 if ( size
< 180 ) return 0 ;
1409 // prime i to first up transition
1410 for ( i
= 160 ; i
< size
- 20 ; i
++)
1411 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
] >= BitStream
[ i
+ 1 ])
1414 for (; i
< size
- 20 ; i
++){
1415 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
] >= BitStream
[ i
+ 1 ]){
1416 // new up transition
1419 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1420 if ( lastFCcnt
== 5 && fcCounter
== 9 ) fcCounter
--;
1421 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1422 if (( fcCounter
== 9 ) || fcCounter
== 4 ) fcCounter
++;
1423 // save last field clock count (fc/xx)
1424 lastFCcnt
= fcCounter
;
1426 // find which fcLens to save it to:
1427 for ( int ii
= 0 ; ii
< 15 ; ii
++){
1428 if ( fcLens
[ ii
]== fcCounter
){
1434 if ( fcCounter
> 0 && fcLensFnd
< 15 ){
1436 fcCnts
[ fcLensFnd
]++;
1437 fcLens
[ fcLensFnd
++]= fcCounter
;
1446 uint8_t best1
= 14 , best2
= 14 , best3
= 14 ;
1448 // go through fclens and find which ones are bigest 2
1449 for ( i
= 0 ; i
< 15 ; i
++){
1450 // get the 3 best FC values
1451 if ( fcCnts
[ i
]> maxCnt1
) {
1456 } else if ( fcCnts
[ i
]> fcCnts
[ best2
]){
1459 } else if ( fcCnts
[ i
]> fcCnts
[ best3
]){
1462 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
]);
1464 if ( fcLens
[ best1
]== 0 ) return 0 ;
1465 uint8_t fcH
= 0 , fcL
= 0 ;
1466 if ( fcLens
[ best1
]> fcLens
[ best2
]){
1473 if (( size
- 180 )/ fcH
/ 3 > fcCnts
[ best1
]+ fcCnts
[ best2
]) {
1474 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
]);
1475 return 0 ; //lots of waves not psk or fsk
1477 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1479 uint16_t fcs
= ((( uint16_t ) fcH
)<< 8 ) | fcL
;
1480 if ( fskAdj
) return fcs
;
1481 return fcLens
[ best1
];
1484 //by marshmellow - demodulate PSK1 wave
1485 //uses wave lengths (# Samples)
1486 int pskRawDemod ( uint8_t dest
[], size_t * size
, int * clock
, int * invert
)
1488 if ( size
== 0 ) return - 1 ;
1489 uint16_t loopCnt
= 4096 ; //don't need to loop through entire array...
1490 if (* size
< loopCnt
) loopCnt
= * size
;
1493 uint8_t curPhase
= * invert
;
1494 size_t i
, waveStart
= 1 , waveEnd
= 0 , firstFullWave
= 0 , lastClkBit
= 0 ;
1495 uint8_t fc
= 0 , fullWaveLen
= 0 , tol
= 1 ;
1496 uint16_t errCnt
= 0 , waveLenCnt
= 0 ;
1497 fc
= countFC ( dest
, * size
, 0 );
1498 if ( fc
!= 2 && fc
!= 4 && fc
!= 8 ) return - 1 ;
1499 //PrintAndLog("DEBUG: FC: %d",fc);
1500 * clock
= DetectPSKClock ( dest
, * size
, * clock
);
1501 if (* clock
== 0 ) return - 1 ;
1502 int avgWaveVal
= 0 , lastAvgWaveVal
= 0 ;
1503 //find first phase shift
1504 for ( i
= 0 ; i
< loopCnt
; i
++){
1505 if ( dest
[ i
]+ fc
< dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1507 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1508 waveLenCnt
= waveEnd
- waveStart
;
1509 if ( waveLenCnt
> fc
&& waveStart
> fc
&& !( waveLenCnt
> fc
+ 2 )){ //not first peak and is a large wave but not out of whack
1510 lastAvgWaveVal
= avgWaveVal
/( waveLenCnt
);
1511 firstFullWave
= waveStart
;
1512 fullWaveLen
= waveLenCnt
;
1513 //if average wave value is > graph 0 then it is an up wave or a 1
1514 if ( lastAvgWaveVal
> 123 ) curPhase
^= 1 ; //fudge graph 0 a little 123 vs 128
1520 avgWaveVal
+= dest
[ i
+ 2 ];
1522 if ( firstFullWave
== 0 ) {
1523 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1524 // so skip a little to ensure we are past any Start Signal
1525 firstFullWave
= 160 ;
1526 memset ( dest
, curPhase
, firstFullWave
/ * clock
);
1528 memset ( dest
, curPhase
^ 1 , firstFullWave
/ * clock
);
1531 numBits
+= ( firstFullWave
/ * clock
);
1532 //set start of wave as clock align
1533 lastClkBit
= firstFullWave
;
1534 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: firstFullWave: %u, waveLen: %u" , firstFullWave
, fullWaveLen
);
1535 if ( g_debugMode
== 2 ) prnt ( "DEBUG: clk: %d, lastClkBit: %u, fc: %u" , * clock
, lastClkBit
,( unsigned int ) fc
);
1537 dest
[ numBits
++] = curPhase
; //set first read bit
1538 for ( i
= firstFullWave
+ fullWaveLen
- 1 ; i
< * size
- 3 ; i
++){
1539 //top edge of wave = start of new wave
1540 if ( dest
[ i
]+ fc
< dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1541 if ( waveStart
== 0 ) {
1544 avgWaveVal
= dest
[ i
+ 1 ];
1547 waveLenCnt
= waveEnd
- waveStart
;
1548 lastAvgWaveVal
= avgWaveVal
/ waveLenCnt
;
1549 if ( waveLenCnt
> fc
){
1550 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1551 //this wave is a phase shift
1552 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1553 if ( i
+ 1 >= lastClkBit
+ * clock
- tol
){ //should be a clock bit
1555 dest
[ numBits
++] = curPhase
;
1556 lastClkBit
+= * clock
;
1557 } else if ( i
< lastClkBit
+ 10 + fc
){
1558 //noise after a phase shift - ignore
1559 } else { //phase shift before supposed to based on clock
1561 dest
[ numBits
++] = 7 ;
1563 } else if ( i
+ 1 > lastClkBit
+ * clock
+ tol
+ fc
){
1564 lastClkBit
+= * clock
; //no phase shift but clock bit
1565 dest
[ numBits
++] = curPhase
;
1571 avgWaveVal
+= dest
[ i
+ 1 ];
1578 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1579 bool DetectST ( uint8_t buffer
[], size_t * size
, int * foundclock
) {
1580 size_t bufsize
= * size
;
1581 //need to loop through all samples and identify our clock, look for the ST pattern
1582 uint8_t fndClk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 128 };
1585 int i
, j
, skip
, start
, end
, low
, high
, minClk
, waveStart
;
1586 bool complete
= false ;
1587 int tmpbuff
[ bufsize
/ 32 ]; //guess rf/32 clock, if click is smaller we will only have room for a fraction of the samples captured
1588 int waveLen
[ bufsize
/ 32 ]; // if clock is larger then we waste memory in array size that is not needed...
1589 size_t testsize
= ( bufsize
< 512 ) ? bufsize
: 512 ;
1592 memset ( tmpbuff
, 0 , sizeof ( tmpbuff
));
1594 if ( getHiLo ( buffer
, testsize
, & high
, & low
, 80 , 80 ) == - 1 ) {
1595 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: just noise detected - quitting" );
1596 return false ; //just noise
1601 // get to first full low to prime loop and skip incomplete first pulse
1602 while (( buffer
[ i
] < high
) && ( i
< bufsize
))
1604 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1608 // populate tmpbuff buffer with pulse lengths
1609 while ( i
< bufsize
) {
1610 // measure from low to low
1611 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1614 while (( buffer
[ i
] < high
) && ( i
< bufsize
))
1616 //first high point for this wave
1618 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1620 if ( j
>= ( bufsize
/ 32 )) {
1623 waveLen
[ j
] = i
- waveStart
; //first high to first low
1624 tmpbuff
[ j
++] = i
- start
;
1625 if ( i
- start
< minClk
&& i
< bufsize
) {
1629 // set clock - might be able to get this externally and remove this work...
1631 for ( uint8_t clkCnt
= 0 ; clkCnt
< 7 ; clkCnt
++) {
1632 tol
= fndClk
[ clkCnt
]/ 8 ;
1633 if ( minClk
>= fndClk
[ clkCnt
]- tol
&& minClk
<= fndClk
[ clkCnt
]+ 1 ) {
1638 // clock not found - ERROR
1640 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: clock not found - quitting" );
1647 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1649 for ( i
= 0 ; i
< j
- 4 ; ++ i
) {
1651 if ( tmpbuff
[ i
] >= clk
* 1 - tol
&& tmpbuff
[ i
] <= ( clk
* 2 )+ tol
&& waveLen
[ i
] < clk
+ tol
) { //1 to 2 clocks depending on 2 bits prior
1652 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
1653 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
1654 if ( tmpbuff
[ i
+ 3 ] >= clk
* 1 - tol
&& tmpbuff
[ i
+ 3 ] <= clk
* 2 + tol
) { //1 to 2 clocks for end of ST + first bit
1662 // first ST not found - ERROR
1664 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: first STT not found - quitting" );
1667 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: first STT found at: %d, j=%d" , start
, j
);
1669 if ( waveLen
[ i
+ 2 ] > clk
* 1 + tol
)
1674 // skip over the remainder of ST
1675 skip
+= clk
* 7 / 2 ; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1677 // now do it again to find the end
1679 for ( i
+= 3 ; i
< j
- 4 ; ++ i
) {
1681 if ( tmpbuff
[ i
] >= clk
* 1 - tol
&& tmpbuff
[ i
] <= ( clk
* 2 )+ tol
&& waveLen
[ i
] < clk
+ tol
) { //1 to 2 clocks depending on 2 bits prior
1682 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
1683 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
1684 if ( tmpbuff
[ i
+ 3 ] >= clk
* 1 - tol
&& tmpbuff
[ i
+ 3 ] <= clk
* 2 + tol
) { //1 to 2 clocks for end of ST + first bit
1693 //didn't find second ST - ERROR
1695 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: second STT not found - quitting" );
1698 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
);
1699 //now begin to trim out ST so we can use normal demod cmds
1701 size_t datalen
= end
- start
;
1702 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1703 if ( clk
- ( datalen
% clk
) <= clk
/ 8 ) {
1704 // padd the amount off - could be problematic... but shouldn't happen often
1705 datalen
+= clk
- ( datalen
% clk
);
1706 } else if ( ( datalen
% clk
) <= clk
/ 8 ) {
1707 // padd the amount off - could be problematic... but shouldn't happen often
1708 datalen
-= datalen
% clk
;
1710 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting" , datalen
, clk
, datalen
% clk
);
1713 // if datalen is less than one t55xx block - ERROR
1714 if ( datalen
/ clk
< 8 * 4 ) {
1715 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: datalen is less than 1 full t55xx block - quitting" );
1718 size_t dataloc
= start
;
1719 if ( buffer
[ dataloc
-( clk
* 4 )-( clk
/ 8 )] <= low
&& buffer
[ dataloc
] <= low
&& buffer
[ dataloc
-( clk
* 4 )] >= high
) {
1720 //we have low drift (and a low just before the ST and a low just after the ST) - compensate by backing up the start
1721 for ( i
= 0 ; i
<= ( clk
/ 8 ); ++ i
) {
1722 if ( buffer
[ dataloc
- ( clk
* 4 ) - i
] <= low
) {
1731 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: Starting STT trim - start: %d, datalen: %d " , dataloc
, datalen
);
1733 // warning - overwriting buffer given with raw wave data with ST removed...
1734 while ( dataloc
< bufsize
-( clk
/ 2 ) ) {
1735 //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)
1736 if ( buffer
[ dataloc
]< high
&& buffer
[ dataloc
]> low
&& buffer
[ dataloc
+ 3 ]< high
&& buffer
[ dataloc
+ 3 ]> low
) {
1737 for ( i
= 0 ; i
< clk
/ 2 - tol
; ++ i
) {
1738 buffer
[ dataloc
+ i
] = high
+ 5 ;
1741 for ( i
= 0 ; i
< datalen
; ++ i
) {
1742 if ( i
+ newloc
< bufsize
) {
1743 if ( i
+ newloc
< dataloc
)
1744 buffer
[ i
+ newloc
] = buffer
[ dataloc
];
1750 //skip next ST - we just assume it will be there from now on...
1751 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: skipping STT at %d to %d" , dataloc
, dataloc
+( clk
* 4 ));