]>
cvs.zerfleddert.de Git - proxmark3-svn/blob - common/lfdemod.c
d6c024fab9bfa872d9a210fa9dfb9334453e6aca
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 //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
]);
110 // if parity fails then return 0
112 case 3 : dest
[ j
++]= 0 ; break ; // marker bit which should be a 0
113 case 2 : dest
[ j
++]= 1 ; break ; // marker bit which should be a 1
115 dest
[ j
++] = parityTest ( parityWd
, pLen
- 1 , pType
) ^ 1 ;
121 // if we got here then all the parities passed
122 //return ID start index and size
126 uint32_t bytebits_to_byte ( uint8_t * src
, size_t numbits
)
129 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
++)
143 num
= ( num
<< 1 ) | *( src
+ ( numbits
-( i
+ 1 )));
149 //search for given preamble in given BitStream and return success=1 or fail=0 and startIndex and length
150 uint8_t preambleSearch ( uint8_t * BitStream
, uint8_t * preamble
, size_t pLen
, size_t * size
, size_t * startIdx
)
153 for ( int idx
= 0 ; idx
< * size
- pLen
; idx
++){
154 if ( memcmp ( BitStream
+ idx
, preamble
, pLen
) == 0 ){
161 * size
= idx
- * startIdx
;
170 //takes 1s and 0s and searches for EM410x format - output EM ID
171 uint8_t Em410xDecode ( uint8_t * BitStream
, size_t * size
, size_t * startIdx
, uint32_t * hi
, uint64_t * lo
)
173 //no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
174 // otherwise could be a void with no arguments
177 if ( BitStream
[ 1 ]> 1 ) return 0 ; //allow only 1s and 0s
179 // 111111111 bit pattern represent start of frame
180 // include 0 in front to help get start pos
181 uint8_t preamble
[] = { 0 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 , 1 };
183 uint32_t parityBits
= 0 ;
187 errChk
= preambleSearch ( BitStream
, preamble
, sizeof ( preamble
), size
, startIdx
);
188 if ( errChk
== 0 || * size
< 64 ) return 0 ;
189 if (* size
> 64 ) FmtLen
= 22 ;
190 * startIdx
+= 1 ; //get rid of 0 from preamble
192 for ( i
= 0 ; i
< FmtLen
; i
++){ //loop through 10 or 22 sets of 5 bits (50-10p = 40 bits or 88 bits)
193 parityBits
= bytebits_to_byte ( BitStream
+( i
* 5 )+ idx
, 5 );
194 //check even parity - quit if failed
195 if ( parityTest ( parityBits
, 5 , 0 ) == 0 ) return 0 ;
196 //set uint64 with ID from BitStream
197 for ( uint8_t ii
= 0 ; ii
< 4 ; ii
++){
198 * hi
= (* hi
<< 1 ) | (* lo
>> 63 );
199 * lo
= (* lo
<< 1 ) | ( BitStream
[( i
* 5 )+ ii
+ idx
]);
202 if ( errChk
!= 0 ) return 1 ;
203 //skip last 5 bit parity test for simplicity.
209 //demodulates strong heavily clipped samples
210 int cleanAskRawDemod ( uint8_t * BinStream
, size_t * size
, int clk
, int invert
, int high
, int low
)
212 size_t bitCnt
= 0 , smplCnt
= 0 , errCnt
= 0 ;
213 uint8_t waveHigh
= 0 ;
214 for ( size_t i
= 0 ; i
< * size
; i
++){
215 if ( BinStream
[ i
] >= high
&& waveHigh
){
217 } else if ( BinStream
[ i
] <= low
&& ! waveHigh
){
219 } else { //transition
220 if (( BinStream
[ i
] >= high
&& ! waveHigh
) || ( BinStream
[ i
] <= low
&& waveHigh
)){
221 if ( smplCnt
> clk
-( clk
/ 4 )- 1 ) { //full clock
222 if ( smplCnt
> clk
+ ( clk
/ 4 )+ 1 ) { //too many samples
224 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Modulation Error at: %u" , i
);
225 BinStream
[ bitCnt
++]= 7 ;
226 } else if ( waveHigh
) {
227 BinStream
[ bitCnt
++] = invert
;
228 BinStream
[ bitCnt
++] = invert
;
229 } else if (! waveHigh
) {
230 BinStream
[ bitCnt
++] = invert
^ 1 ;
231 BinStream
[ bitCnt
++] = invert
^ 1 ;
235 } else if ( smplCnt
> ( clk
/ 2 ) - ( clk
/ 4 )- 1 ) {
237 BinStream
[ bitCnt
++] = invert
;
238 } else if (! waveHigh
) {
239 BinStream
[ bitCnt
++] = invert
^ 1 ;
243 } else if (! bitCnt
) {
245 waveHigh
= ( BinStream
[ i
] >= high
);
249 //transition bit oops
251 } else { //haven't hit new high or new low yet
261 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
]- BitStream
[ i
- 1 ]<=- 20 ) //large jump down
273 //attempts to demodulate ask modulations, askType == 0 for ask/raw, askType==1 for ask/manchester
274 int askdemod ( uint8_t * BinStream
, size_t * size
, int * clk
, int * invert
, int maxErr
, uint8_t amp
, uint8_t askType
)
276 if (* size
== 0 ) return - 1 ;
277 int start
= DetectASKClock ( BinStream
, * size
, clk
, maxErr
); //clock default
278 if (* clk
== 0 || start
< 0 ) return - 3 ;
279 if (* invert
!= 1 ) * invert
= 0 ;
280 if ( amp
== 1 ) askAmp ( BinStream
, * size
);
281 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: clk %d, beststart %d" , * clk
, start
);
283 uint8_t initLoopMax
= 255 ;
284 if ( initLoopMax
> * size
) initLoopMax
= * size
;
285 // Detect high and lows
286 //25% clip in case highs and lows aren't clipped [marshmellow]
288 if ( getHiLo ( BinStream
, initLoopMax
, & high
, & low
, 75 , 75 ) < 1 )
289 return - 2 ; //just noise
292 // if clean clipped waves detected run alternate demod
293 if ( DetectCleanAskWave ( BinStream
, * size
, high
, low
)) {
294 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Clean Wave Detected - using clean wave demod" );
295 errCnt
= cleanAskRawDemod ( BinStream
, size
, * clk
, * invert
, high
, low
);
296 if ( askType
) //askman
297 return manrawdecode ( BinStream
, size
, 0 );
301 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Weak Wave Detected - using weak wave demod" );
303 int lastBit
; //set first clock check - can go negative
304 size_t i
, bitnum
= 0 ; //output counter
306 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
307 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
308 size_t MaxBits
= 3072 ; //max bits to collect
309 lastBit
= start
- * clk
;
311 for ( i
= start
; i
< * size
; ++ i
) {
312 if ( i
- lastBit
>= * clk
- tol
){
313 if ( BinStream
[ i
] >= high
) {
314 BinStream
[ bitnum
++] = * invert
;
315 } else if ( BinStream
[ i
] <= low
) {
316 BinStream
[ bitnum
++] = * invert
^ 1 ;
317 } else if ( i
- lastBit
>= * clk
+ tol
) {
319 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: Modulation Error at: %u" , i
);
320 BinStream
[ bitnum
++]= 7 ;
323 } else { //in tolerance - looking for peak
328 } else if ( i
- lastBit
>= (* clk
/ 2 - tol
) && ! midBit
&& ! askType
){
329 if ( BinStream
[ i
] >= high
) {
330 BinStream
[ bitnum
++] = * invert
;
331 } else if ( BinStream
[ i
] <= low
) {
332 BinStream
[ bitnum
++] = * invert
^ 1 ;
333 } else if ( i
- lastBit
>= * clk
/ 2 + tol
) {
334 BinStream
[ bitnum
] = BinStream
[ bitnum
- 1 ];
336 } else { //in tolerance - looking for peak
341 if ( bitnum
>= MaxBits
) break ;
348 //take 10 and 01 and manchester decode
349 //run through 2 times and take least errCnt
350 int manrawdecode ( uint8_t * BitStream
, size_t * size
, uint8_t invert
)
352 uint16_t bitnum
= 0 , MaxBits
= 512 , errCnt
= 0 ;
354 uint16_t bestErr
= 1000 , bestRun
= 0 ;
355 if (* size
< 16 ) return - 1 ;
356 //find correct start position [alignment]
357 for ( ii
= 0 ; ii
< 2 ;++ ii
){
358 for ( i
= ii
; i
<* size
- 3 ; i
+= 2 )
359 if ( BitStream
[ i
]== BitStream
[ i
+ 1 ])
369 for ( i
= bestRun
; i
< * size
- 3 ; i
+= 2 ){
370 if ( BitStream
[ i
] == 1 && ( BitStream
[ i
+ 1 ] == 0 )){
371 BitStream
[ bitnum
++]= invert
;
372 } else if (( BitStream
[ i
] == 0 ) && BitStream
[ i
+ 1 ] == 1 ){
373 BitStream
[ bitnum
++]= invert
^ 1 ;
375 BitStream
[ bitnum
++]= 7 ;
377 if ( bitnum
> MaxBits
) break ;
383 uint32_t manchesterEncode2Bytes ( uint16_t datain
) {
386 for ( uint8_t i
= 0 ; i
< 16 ; i
++) {
387 curBit
= ( datain
>> ( 15 - i
) & 1 );
388 output
|= ( 1 <<((( 15 - i
)* 2 )+ curBit
));
394 //encode binary data into binary manchester
395 int ManchesterEncode ( uint8_t * BitStream
, size_t size
)
397 size_t modIdx
= 20000 , i
= 0 ;
398 if ( size
> modIdx
) return - 1 ;
399 for ( size_t idx
= 0 ; idx
< size
; idx
++){
400 BitStream
[ idx
+ modIdx
++] = BitStream
[ idx
];
401 BitStream
[ idx
+ modIdx
++] = BitStream
[ idx
]^ 1 ;
403 for (; i
<( size
* 2 ); i
++){
404 BitStream
[ i
] = BitStream
[ i
+ 20000 ];
410 //take 01 or 10 = 1 and 11 or 00 = 0
411 //check for phase errors - should never have 111 or 000 should be 01001011 or 10110100 for 1010
412 //decodes biphase or if inverted it is AKA conditional dephase encoding AKA differential manchester encoding
413 int BiphaseRawDecode ( uint8_t * BitStream
, size_t * size
, int offset
, int invert
)
418 uint16_t MaxBits
= 512 ;
419 //if not enough samples - error
420 if (* size
< 51 ) return - 1 ;
421 //check for phase change faults - skip one sample if faulty
422 uint8_t offsetA
= 1 , offsetB
= 1 ;
424 if ( BitStream
[ i
+ 1 ]== BitStream
[ i
+ 2 ]) offsetA
= 0 ;
425 if ( BitStream
[ i
+ 2 ]== BitStream
[ i
+ 3 ]) offsetB
= 0 ;
427 if (! offsetA
&& offsetB
) offset
++;
428 for ( i
= offset
; i
<* size
- 3 ; i
+= 2 ){
429 //check for phase error
430 if ( BitStream
[ i
+ 1 ]== BitStream
[ i
+ 2 ]) {
431 BitStream
[ bitnum
++]= 7 ;
434 if (( BitStream
[ i
]== 1 && BitStream
[ i
+ 1 ]== 0 ) || ( BitStream
[ i
]== 0 && BitStream
[ i
+ 1 ]== 1 )){
435 BitStream
[ bitnum
++]= 1 ^ invert
;
436 } else if (( BitStream
[ i
]== 0 && BitStream
[ i
+ 1 ]== 0 ) || ( BitStream
[ i
]== 1 && BitStream
[ i
+ 1 ]== 1 )){
437 BitStream
[ bitnum
++]= invert
;
439 BitStream
[ bitnum
++]= 7 ;
442 if ( bitnum
> MaxBits
) break ;
449 // demod gProxIIDemod
450 // error returns as -x
451 // success returns start position in BitStream
452 // BitStream must contain previously askrawdemod and biphasedemoded data
453 int gProxII_Demod ( uint8_t BitStream
[], size_t * size
)
456 uint8_t preamble
[] = { 1 , 1 , 1 , 1 , 1 , 0 };
458 uint8_t errChk
= preambleSearch ( BitStream
, preamble
, sizeof ( preamble
), size
, & startIdx
);
459 if ( errChk
== 0 ) return - 3 ; //preamble not found
460 if (* size
!= 96 ) return - 2 ; //should have found 96 bits
461 //check first 6 spacer bits to verify format
462 if (! BitStream
[ startIdx
+ 5 ] && ! BitStream
[ startIdx
+ 10 ] && ! BitStream
[ startIdx
+ 15 ] && ! BitStream
[ startIdx
+ 20 ] && ! BitStream
[ startIdx
+ 25 ] && ! BitStream
[ startIdx
+ 30 ]){
463 //confirmed proper separator bits found
464 //return start position
465 return ( int ) startIdx
;
470 //translate wave to 11111100000 (1 for each short wave 0 for each long wave)
471 size_t fsk_wave_demod ( uint8_t * dest
, size_t size
, uint8_t fchigh
, uint8_t fclow
)
473 size_t last_transition
= 0 ;
476 if ( fchigh
== 0 ) fchigh
= 10 ;
477 if ( fclow
== 0 ) fclow
= 8 ;
478 //set the threshold close to 0 (graph) or 128 std to avoid static
479 uint8_t threshold_value
= 123 ;
480 size_t preLastSample
= 0 ;
481 size_t LastSample
= 0 ;
482 size_t currSample
= 0 ;
483 // sync to first lo-hi transition, and threshold
485 // Need to threshold first sample
486 // skip 160 samples to allow antenna/samples to settle
487 if ( dest
[ 160 ] < threshold_value
) dest
[ 0 ] = 0 ;
491 // count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
492 // or 10 (fc/10) cycles but in practice due to noise etc we may end up with anywhere
493 // between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
494 for ( idx
= 161 ; idx
< size
- 20 ; idx
++) {
495 // threshold current value
497 if ( dest
[ idx
] < threshold_value
) dest
[ idx
] = 0 ;
500 // Check for 0->1 transition
501 if ( dest
[ idx
- 1 ] < dest
[ idx
]) { // 0 -> 1 transition
502 preLastSample
= LastSample
;
503 LastSample
= currSample
;
504 currSample
= idx
- last_transition
;
505 if ( currSample
< ( fclow
- 2 )){ //0-5 = garbage noise (or 0-3)
506 //do nothing with extra garbage
507 } else if ( currSample
< ( fchigh
- 1 )) { //6-8 = 8 sample waves or 3-6 = 5
508 if ( LastSample
> ( fchigh
- 2 ) && ( preLastSample
< ( fchigh
- 1 ) || preLastSample
== 0 )){
509 dest
[ numBits
- 1 ]= 1 ; //correct previous 9 wave surrounded by 8 waves
513 } else if ( currSample
> ( fchigh
) && ! numBits
) { //12 + and first bit = garbage
514 //do nothing with beginning garbage
515 } else if ( currSample
== ( fclow
+ 1 ) && LastSample
== ( fclow
- 1 )) { // had a 7 then a 9 should be two 8's
517 } else { //9+ = 10 sample waves
520 last_transition
= idx
;
523 return numBits
; //Actually, it returns the number of bytes, but each byte represents a bit: 1 or 0
526 //translate 11111100000 to 10
527 size_t aggregate_bits ( uint8_t * dest
, size_t size
, uint8_t rfLen
,
528 uint8_t invert
, uint8_t fchigh
, uint8_t fclow
)
530 uint8_t lastval
= dest
[ 0 ];
534 for ( idx
= 1 ; idx
< size
; idx
++) {
536 if ( dest
[ idx
]== lastval
) continue ;
538 //if lastval was 1, we have a 1->0 crossing
539 if ( dest
[ idx
- 1 ]== 1 ) {
540 n
= ( n
* fclow
+ rfLen
/ 2 ) / rfLen
;
541 } else { // 0->1 crossing
542 n
= ( n
* fchigh
+ rfLen
/ 2 ) / rfLen
;
546 memset ( dest
+ numBits
, dest
[ idx
- 1 ]^ invert
, n
);
551 // if valid extra bits at the end were all the same frequency - add them in
552 if ( n
> rfLen
/ fchigh
) {
553 if ( dest
[ idx
- 2 ]== 1 ) {
554 n
= ( n
* fclow
+ rfLen
/ 2 ) / rfLen
;
556 n
= ( n
* fchigh
+ rfLen
/ 2 ) / rfLen
;
558 memset ( dest
+ numBits
, dest
[ idx
- 1 ]^ invert
, n
);
564 //by marshmellow (from holiman's base)
565 // full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
566 int fskdemod ( uint8_t * dest
, size_t size
, uint8_t rfLen
, uint8_t invert
, uint8_t fchigh
, uint8_t fclow
)
569 size
= fsk_wave_demod ( dest
, size
, fchigh
, fclow
);
570 size
= aggregate_bits ( dest
, size
, rfLen
, invert
, fchigh
, fclow
);
574 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
575 int HIDdemodFSK ( uint8_t * dest
, size_t * size
, uint32_t * hi2
, uint32_t * hi
, uint32_t * lo
)
577 if ( justNoise ( dest
, * size
)) return - 1 ;
579 size_t numStart
= 0 , size2
=* size
, startIdx
= 0 ;
581 * size
= fskdemod ( dest
, size2
, 50 , 1 , 10 , 8 ); //fsk2a
582 if (* size
< 96 * 2 ) return - 2 ;
583 // 00011101 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
584 uint8_t preamble
[] = { 0 , 0 , 0 , 1 , 1 , 1 , 0 , 1 };
585 // find bitstring in array
586 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
587 if ( errChk
== 0 ) return - 3 ; //preamble not found
589 numStart
= startIdx
+ sizeof ( preamble
);
590 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
591 for ( size_t idx
= numStart
; ( idx
- numStart
) < * size
- sizeof ( preamble
); idx
+= 2 ){
592 if ( dest
[ idx
] == dest
[ idx
+ 1 ]){
593 return - 4 ; //not manchester data
595 * hi2
= (* hi2
<< 1 )|(* hi
>> 31 );
596 * hi
= (* hi
<< 1 )|(* lo
>> 31 );
597 //Then, shift in a 0 or one into low
598 if ( dest
[ idx
] && ! dest
[ idx
+ 1 ]) // 1 0
603 return ( int ) startIdx
;
606 // loop to get raw paradox waveform then FSK demodulate the TAG ID from it
607 int ParadoxdemodFSK ( uint8_t * dest
, size_t * size
, uint32_t * hi2
, uint32_t * hi
, uint32_t * lo
)
609 if ( justNoise ( dest
, * size
)) return - 1 ;
611 size_t numStart
= 0 , size2
=* size
, startIdx
= 0 ;
613 * size
= fskdemod ( dest
, size2
, 50 , 1 , 10 , 8 ); //fsk2a
614 if (* size
< 96 ) return - 2 ;
616 // 00001111 bit pattern represent start of frame, 01 pattern represents a 0 and 10 represents a 1
617 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 1 , 1 , 1 , 1 };
619 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
620 if ( errChk
== 0 ) return - 3 ; //preamble not found
622 numStart
= startIdx
+ sizeof ( preamble
);
623 // final loop, go over previously decoded FSK data and manchester decode into usable tag ID
624 for ( size_t idx
= numStart
; ( idx
- numStart
) < * size
- sizeof ( preamble
); idx
+= 2 ){
625 if ( dest
[ idx
] == dest
[ idx
+ 1 ])
626 return - 4 ; //not manchester data
627 * hi2
= (* hi2
<< 1 )|(* hi
>> 31 );
628 * hi
= (* hi
<< 1 )|(* lo
>> 31 );
629 //Then, shift in a 0 or one into low
630 if ( dest
[ idx
] && ! dest
[ idx
+ 1 ]) // 1 0
635 return ( int ) startIdx
;
638 int IOdemodFSK ( uint8_t * dest
, size_t size
)
640 if ( justNoise ( dest
, size
)) return - 1 ;
641 //make sure buffer has data
642 if ( size
< 66 * 64 ) return - 2 ;
644 size
= fskdemod ( dest
, size
, 64 , 1 , 10 , 8 ); // FSK2a RF/64
645 if ( size
< 65 ) return - 3 ; //did we get a good demod?
647 //0 10 20 30 40 50 60
649 //01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
650 //-----------------------------------------------------------------------------
651 //00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
653 //XSF(version)facility:codeone+codetwo
656 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
657 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), & size
, & startIdx
);
658 if ( errChk
== 0 ) return - 4 ; //preamble not found
660 if (! dest
[ startIdx
+ 8 ] && dest
[ startIdx
+ 17 ]== 1 && dest
[ startIdx
+ 26 ]== 1 && dest
[ startIdx
+ 35 ]== 1 && dest
[ startIdx
+ 44 ]== 1 && dest
[ startIdx
+ 53 ]== 1 ){
661 //confirmed proper separator bits found
662 //return start position
663 return ( int ) startIdx
;
669 // find viking preamble 0xF200 in already demoded data
670 int VikingDemod_AM ( uint8_t * dest
, size_t * size
) {
671 //make sure buffer has data
672 if (* size
< 64 * 2 ) return - 2 ;
675 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 };
676 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
677 if ( errChk
== 0 ) return - 4 ; //preamble not found
678 uint32_t checkCalc
= bytebits_to_byte ( dest
+ startIdx
, 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 8 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 16 , 8 )
679 ^ bytebits_to_byte ( dest
+ startIdx
+ 24 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 32 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 40 , 8 )
680 ^ bytebits_to_byte ( dest
+ startIdx
+ 48 , 8 ) ^ bytebits_to_byte ( dest
+ startIdx
+ 56 , 8 );
681 if ( checkCalc
!= 0xA8 ) return - 5 ;
682 if (* size
!= 64 ) return - 6 ;
683 //return start position
684 return ( int ) startIdx
;
687 // find presco preamble 0x10D in already demoded data
688 int PrescoDemod ( uint8_t * dest
, size_t * size
) {
689 //make sure buffer has data
690 if (* size
< 64 * 2 ) return - 2 ;
693 uint8_t preamble
[] = { 1 , 0 , 0 , 0 , 0 , 1 , 1 , 0 , 1 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
694 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
695 if ( errChk
== 0 ) return - 4 ; //preamble not found
696 //return start position
697 return ( int ) startIdx
;
700 // Ask/Biphase Demod then try to locate an ISO 11784/85 ID
701 // BitStream must contain previously askrawdemod and biphasedemoded data
702 int FDXBdemodBI ( uint8_t * dest
, size_t * size
)
704 //make sure buffer has enough data
705 if (* size
< 128 ) return - 1 ;
708 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
710 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
711 if ( errChk
== 0 ) return - 2 ; //preamble not found
712 return ( int ) startIdx
;
716 // FSK Demod then try to locate an AWID ID
717 int AWIDdemodFSK ( uint8_t * dest
, size_t * size
)
719 //make sure buffer has enough data
720 if (* size
< 96 * 50 ) return - 1 ;
722 if ( justNoise ( dest
, * size
)) return - 2 ;
725 * size
= fskdemod ( dest
, * size
, 50 , 1 , 10 , 8 ); // fsk2a RF/50
726 if (* size
< 96 ) return - 3 ; //did we get a good demod?
728 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
730 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
731 if ( errChk
== 0 ) return - 4 ; //preamble not found
732 if (* size
!= 96 ) return - 5 ;
733 return ( int ) startIdx
;
737 // FSK Demod then try to locate a Farpointe Data (pyramid) ID
738 int PyramiddemodFSK ( uint8_t * dest
, size_t * size
)
740 //make sure buffer has data
741 if (* size
< 128 * 50 ) return - 5 ;
743 //test samples are not just noise
744 if ( justNoise ( dest
, * size
)) return - 1 ;
747 * size
= fskdemod ( dest
, * size
, 50 , 1 , 10 , 8 ); // fsk2a RF/50
748 if (* size
< 128 ) return - 2 ; //did we get a good demod?
750 uint8_t preamble
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 1 };
752 uint8_t errChk
= preambleSearch ( dest
, preamble
, sizeof ( preamble
), size
, & startIdx
);
753 if ( errChk
== 0 ) return - 4 ; //preamble not found
754 if (* size
!= 128 ) return - 3 ;
755 return ( int ) startIdx
;
759 // to detect a wave that has heavily clipped (clean) samples
760 uint8_t DetectCleanAskWave ( uint8_t dest
[], size_t size
, uint8_t high
, uint8_t low
)
762 bool allArePeaks
= true ;
764 size_t loopEnd
= 512 + 160 ;
765 if ( loopEnd
> size
) loopEnd
= size
;
766 for ( size_t i
= 160 ; i
< loopEnd
; i
++){
767 if ( dest
[ i
]> low
&& dest
[ i
]< high
)
773 if ( cntPeaks
> 300 ) return true ;
778 // to help detect clocks on heavily clipped samples
779 // based on count of low to low
780 int DetectStrongAskClock ( uint8_t dest
[], size_t size
, uint8_t high
, uint8_t low
)
782 uint8_t fndClk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 128 };
786 // get to first full low to prime loop and skip incomplete first pulse
787 while (( dest
[ i
] < high
) && ( i
< size
))
789 while (( dest
[ i
] > low
) && ( i
< size
))
792 // loop through all samples
794 // measure from low to low
795 while (( dest
[ i
] > low
) && ( i
< size
))
798 while (( dest
[ i
] < high
) && ( i
< size
))
800 while (( dest
[ i
] > low
) && ( i
< size
))
802 //get minimum measured distance
803 if ( i
- startwave
< minClk
&& i
< size
)
804 minClk
= i
- startwave
;
807 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: detectstrongASKclk smallest wave: %d" , minClk
);
808 for ( uint8_t clkCnt
= 0 ; clkCnt
< 7 ; clkCnt
++) {
809 if ( minClk
>= fndClk
[ clkCnt
]-( fndClk
[ clkCnt
]/ 8 ) && minClk
<= fndClk
[ clkCnt
]+ 1 )
810 return fndClk
[ clkCnt
];
816 // not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
817 // maybe somehow adjust peak trimming value based on samples to fix?
818 // return start index of best starting position for that clock and return clock (by reference)
819 int DetectASKClock ( uint8_t dest
[], size_t size
, int * clock
, int maxErr
)
822 uint8_t clk
[] = { 255 , 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 };
824 uint8_t loopCnt
= 255 ; //don't need to loop through entire array...
825 if ( size
<= loopCnt
+ 60 ) return - 1 ; //not enough samples
826 size
-= 60 ; //sometimes there is a strange end wave - filter out this....
827 //if we already have a valid clock
830 if ( clk
[ i
] == * clock
) clockFnd
= i
;
831 //clock found but continue to find best startpos
833 //get high and low peak
835 if ( getHiLo ( dest
, loopCnt
, & peak
, & low
, 75 , 75 ) < 1 ) return - 1 ;
837 //test for large clean peaks
839 if ( DetectCleanAskWave ( dest
, size
, peak
, low
)== 1 ){
840 int ans
= DetectStrongAskClock ( dest
, size
, peak
, low
);
841 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: detectaskclk Clean Ask Wave Detected: clk %d" , ans
);
842 for ( i
= clkEnd
- 1 ; i
> 0 ; i
--){
846 return 0 ; // for strong waves i don't use the 'best start position' yet...
847 //break; //clock found but continue to find best startpos [not yet]
853 uint8_t clkCnt
, tol
= 0 ;
854 uint16_t bestErr
[]={ 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 };
855 uint8_t bestStart
[]={ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
857 size_t arrLoc
, loopEnd
;
865 //test each valid clock from smallest to greatest to see which lines up
866 for (; clkCnt
< clkEnd
; clkCnt
++){
867 if ( clk
[ clkCnt
] <= 32 ){
872 //if no errors allowed - keep start within the first clock
873 if (! maxErr
&& size
> clk
[ clkCnt
]* 2 + tol
&& clk
[ clkCnt
]< 128 ) loopCnt
= clk
[ clkCnt
]* 2 ;
874 bestErr
[ clkCnt
]= 1000 ;
875 //try lining up the peaks by moving starting point (try first few clocks)
876 for ( ii
= 0 ; ii
< loopCnt
; ii
++){
877 if ( dest
[ ii
] < peak
&& dest
[ ii
] > low
) continue ;
880 // now that we have the first one lined up test rest of wave array
881 loopEnd
= (( size
- ii
- tol
) / clk
[ clkCnt
]) - 1 ;
882 for ( i
= 0 ; i
< loopEnd
; ++ i
){
883 arrLoc
= ii
+ ( i
* clk
[ clkCnt
]);
884 if ( dest
[ arrLoc
] >= peak
|| dest
[ arrLoc
] <= low
){
885 } else if ( dest
[ arrLoc
- tol
] >= peak
|| dest
[ arrLoc
- tol
] <= low
){
886 } else if ( dest
[ arrLoc
+ tol
] >= peak
|| dest
[ arrLoc
+ tol
] <= low
){
887 } else { //error no peak detected
891 //if we found no errors then we can stop here and a low clock (common clocks)
892 // this is correct one - return this clock
893 if ( g_debugMode
== 2 ) prnt ( "DEBUG ASK: clk %d, err %d, startpos %d, endpos %d" , clk
[ clkCnt
], errCnt
, ii
, i
);
894 if ( errCnt
== 0 && clkCnt
< 7 ) {
895 if (! clockFnd
) * clock
= clk
[ clkCnt
];
898 //if we found errors see if it is lowest so far and save it as best run
899 if ( errCnt
< bestErr
[ clkCnt
]){
900 bestErr
[ clkCnt
]= errCnt
;
901 bestStart
[ clkCnt
]= ii
;
907 for ( iii
= 1 ; iii
< clkEnd
; ++ iii
){
908 if ( bestErr
[ iii
] < bestErr
[ best
]){
909 if ( bestErr
[ iii
] == 0 ) bestErr
[ iii
]= 1 ;
910 // current best bit to error ratio vs new bit to error ratio
911 if ( ( size
/ clk
[ best
])/ bestErr
[ best
] < ( size
/ clk
[ iii
])/ bestErr
[ iii
] ){
915 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
]);
917 if (! clockFnd
) * clock
= clk
[ best
];
918 return bestStart
[ best
];
922 //detect psk clock by reading each phase shift
923 // a phase shift is determined by measuring the sample length of each wave
924 int DetectPSKClock ( uint8_t dest
[], size_t size
, int clock
)
926 uint8_t clk
[]={ 255 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 }; //255 is not a valid clock
927 uint16_t loopCnt
= 4096 ; //don't need to loop through entire array...
928 if ( size
== 0 ) return 0 ;
929 if ( size
< loopCnt
) loopCnt
= size
- 20 ;
931 //if we already have a valid clock quit
934 if ( clk
[ i
] == clock
) return clock
;
936 size_t waveStart
= 0 , waveEnd
= 0 , firstFullWave
= 0 , lastClkBit
= 0 ;
937 uint8_t clkCnt
, fc
= 0 , fullWaveLen
= 0 , tol
= 1 ;
938 uint16_t peakcnt
= 0 , errCnt
= 0 , waveLenCnt
= 0 ;
939 uint16_t bestErr
[]={ 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 , 1000 };
940 uint16_t peaksdet
[]={ 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
941 fc
= countFC ( dest
, size
, 0 );
942 if ( fc
!= 2 && fc
!= 4 && fc
!= 8 ) return - 1 ;
943 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: FC: %d" , fc
);
945 //find first full wave
946 for ( i
= 160 ; i
< loopCnt
; i
++){
947 if ( dest
[ i
] < dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
948 if ( waveStart
== 0 ) {
950 //prnt("DEBUG: waveStart: %d",waveStart);
953 //prnt("DEBUG: waveEnd: %d",waveEnd);
954 waveLenCnt
= waveEnd
- waveStart
;
955 if ( waveLenCnt
> fc
){
956 firstFullWave
= waveStart
;
957 fullWaveLen
= waveLenCnt
;
964 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: firstFullWave: %d, waveLen: %d" , firstFullWave
, fullWaveLen
);
966 //test each valid clock from greatest to smallest to see which lines up
967 for ( clkCnt
= 7 ; clkCnt
>= 1 ; clkCnt
--){
968 lastClkBit
= firstFullWave
; //set end of wave as clock align
972 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: clk: %d, lastClkBit: %d" , clk
[ clkCnt
], lastClkBit
);
974 for ( i
= firstFullWave
+ fullWaveLen
- 1 ; i
< loopCnt
- 2 ; i
++){
975 //top edge of wave = start of new wave
976 if ( dest
[ i
] < dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
977 if ( waveStart
== 0 ) {
982 waveLenCnt
= waveEnd
- waveStart
;
983 if ( waveLenCnt
> fc
){
984 //if this wave is a phase shift
985 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
);
986 if ( i
+ 1 >= lastClkBit
+ clk
[ clkCnt
] - tol
){ //should be a clock bit
988 lastClkBit
+= clk
[ clkCnt
];
989 } else if ( i
< lastClkBit
+ 8 ){
990 //noise after a phase shift - ignore
991 } else { //phase shift before supposed to based on clock
994 } else if ( i
+ 1 > lastClkBit
+ clk
[ clkCnt
] + tol
+ fc
){
995 lastClkBit
+= clk
[ clkCnt
]; //no phase shift but clock bit
1004 if ( errCnt
<= bestErr
[ clkCnt
]) bestErr
[ clkCnt
]= errCnt
;
1005 if ( peakcnt
> peaksdet
[ clkCnt
]) peaksdet
[ clkCnt
]= peakcnt
;
1007 //all tested with errors
1008 //return the highest clk with the most peaks found
1010 for ( i
= 7 ; i
>= 1 ; i
--){
1011 if ( peaksdet
[ i
] > peaksdet
[ best
]) {
1014 if ( g_debugMode
== 2 ) prnt ( "DEBUG PSK: Clk: %d, peaks: %d, errs: %d, bestClk: %d" , clk
[ i
], peaksdet
[ i
], bestErr
[ i
], clk
[ best
]);
1019 int DetectStrongNRZClk ( uint8_t * dest
, size_t size
, int peak
, int low
){
1020 //find shortest transition from high to low
1022 size_t transition1
= 0 ;
1023 int lowestTransition
= 255 ;
1024 bool lastWasHigh
= false ;
1026 //find first valid beginning of a high or low wave
1027 while (( dest
[ i
] >= peak
|| dest
[ i
] <= low
) && ( i
< size
))
1029 while (( dest
[ i
] < peak
&& dest
[ i
] > low
) && ( i
< size
))
1031 lastWasHigh
= ( dest
[ i
] >= peak
);
1033 if ( i
== size
) return 0 ;
1036 for (; i
< size
; i
++) {
1037 if (( dest
[ i
] >= peak
&& ! lastWasHigh
) || ( dest
[ i
] <= low
&& lastWasHigh
)) {
1038 lastWasHigh
= ( dest
[ i
] >= peak
);
1039 if ( i
- transition1
< lowestTransition
) lowestTransition
= i
- transition1
;
1043 if ( lowestTransition
== 255 ) lowestTransition
= 0 ;
1044 if ( g_debugMode
== 2 ) prnt ( "DEBUG NRZ: detectstrongNRZclk smallest wave: %d" , lowestTransition
);
1045 return lowestTransition
;
1049 //detect nrz clock by reading #peaks vs no peaks(or errors)
1050 int DetectNRZClock ( uint8_t dest
[], size_t size
, int clock
)
1053 uint8_t clk
[]={ 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 255 };
1054 size_t loopCnt
= 4096 ; //don't need to loop through entire array...
1055 if ( size
== 0 ) return 0 ;
1056 if ( size
< loopCnt
) loopCnt
= size
- 20 ;
1057 //if we already have a valid clock quit
1059 if ( clk
[ i
] == clock
) return clock
;
1061 //get high and low peak
1063 if ( getHiLo ( dest
, loopCnt
, & peak
, & low
, 75 , 75 ) < 1 ) return 0 ;
1065 int lowestTransition
= DetectStrongNRZClk ( dest
, size
- 20 , peak
, low
);
1069 uint16_t smplCnt
= 0 ;
1070 int16_t peakcnt
= 0 ;
1071 int16_t peaksdet
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1072 uint16_t maxPeak
= 255 ;
1073 bool firstpeak
= false ;
1074 //test for large clipped waves
1075 for ( i
= 0 ; i
< loopCnt
; i
++){
1076 if ( dest
[ i
] >= peak
|| dest
[ i
] <= low
){
1077 if (! firstpeak
) continue ;
1082 if ( maxPeak
> smplCnt
){
1084 //prnt("maxPk: %d",maxPeak);
1087 //prnt("maxPk: %d, smplCnt: %d, peakcnt: %d",maxPeak,smplCnt,peakcnt);
1092 bool errBitHigh
= 0 ;
1094 uint8_t ignoreCnt
= 0 ;
1095 uint8_t ignoreWindow
= 4 ;
1096 bool lastPeakHigh
= 0 ;
1099 //test each valid clock from smallest to greatest to see which lines up
1100 for ( clkCnt
= 0 ; clkCnt
< 8 ; ++ clkCnt
){
1101 //ignore clocks smaller than smallest peak
1102 if ( clk
[ clkCnt
] < maxPeak
- ( clk
[ clkCnt
]/ 4 )) continue ;
1103 //try lining up the peaks by moving starting point (try first 256)
1104 for ( ii
= 20 ; ii
< loopCnt
; ++ ii
){
1105 if (( dest
[ ii
] >= peak
) || ( dest
[ ii
] <= low
)){
1109 lastBit
= ii
- clk
[ clkCnt
];
1110 //loop through to see if this start location works
1111 for ( i
= ii
; i
< size
- 20 ; ++ i
) {
1112 //if we are at a clock bit
1113 if (( i
>= lastBit
+ clk
[ clkCnt
] - tol
) && ( i
<= lastBit
+ clk
[ clkCnt
] + tol
)) {
1115 if ( dest
[ i
] >= peak
|| dest
[ i
] <= low
) {
1116 //if same peak don't count it
1117 if (( dest
[ i
] >= peak
&& ! lastPeakHigh
) || ( dest
[ i
] <= low
&& lastPeakHigh
)) {
1120 lastPeakHigh
= ( dest
[ i
] >= peak
);
1123 ignoreCnt
= ignoreWindow
;
1124 lastBit
+= clk
[ clkCnt
];
1125 } else if ( i
== lastBit
+ clk
[ clkCnt
] + tol
) {
1126 lastBit
+= clk
[ clkCnt
];
1128 //else if not a clock bit and no peaks
1129 } else if ( dest
[ i
] < peak
&& dest
[ i
] > low
){
1132 if ( errBitHigh
== true ) peakcnt
--;
1137 // else if not a clock bit but we have a peak
1138 } else if (( dest
[ i
]>= peak
|| dest
[ i
]<= low
) && (! bitHigh
)) {
1139 //error bar found no clock...
1143 if ( peakcnt
> peaksdet
[ clkCnt
]) {
1144 peaksdet
[ clkCnt
]= peakcnt
;
1151 for ( iii
= 7 ; iii
> 0 ; iii
--){
1152 if (( peaksdet
[ iii
] >= ( peaksdet
[ best
]- 1 )) && ( peaksdet
[ iii
] <= peaksdet
[ best
]+ 1 ) && lowestTransition
) {
1153 if ( clk
[ iii
] > ( lowestTransition
- ( clk
[ iii
]/ 8 )) && clk
[ iii
] < ( lowestTransition
+ ( clk
[ iii
]/ 8 ))) {
1156 } else if ( peaksdet
[ iii
] > peaksdet
[ best
]){
1159 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
);
1166 // convert psk1 demod to psk2 demod
1167 // only transition waves are 1s
1168 void psk1TOpsk2 ( uint8_t * BitStream
, size_t size
)
1171 uint8_t lastBit
= BitStream
[ 0 ];
1172 for (; i
< size
; i
++){
1173 if ( BitStream
[ i
]== 7 ){
1175 } else if ( lastBit
!= BitStream
[ i
]){
1176 lastBit
= BitStream
[ i
];
1186 // convert psk2 demod to psk1 demod
1187 // from only transition waves are 1s to phase shifts change bit
1188 void psk2TOpsk1 ( uint8_t * BitStream
, size_t size
)
1191 for ( size_t i
= 0 ; i
< size
; i
++){
1192 if ( BitStream
[ i
]== 1 ){
1200 // redesigned by marshmellow adjusted from existing decode functions
1201 // indala id decoding - only tested on 26 bit tags, but attempted to make it work for more
1202 int indala26decode ( uint8_t * bitStream
, size_t * size
, uint8_t * invert
)
1204 //26 bit 40134 format (don't know other formats)
1205 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 };
1206 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 };
1207 size_t startidx
= 0 ;
1208 if (! preambleSearch ( bitStream
, preamble
, sizeof ( preamble
), size
, & startidx
)){
1209 // if didn't find preamble try again inverting
1210 if (! preambleSearch ( bitStream
, preamble_i
, sizeof ( preamble_i
), size
, & startidx
)) return - 1 ;
1213 if (* size
!= 64 && * size
!= 224 ) return - 2 ;
1215 for ( size_t i
= startidx
; i
< * size
; i
++)
1218 return ( int ) startidx
;
1221 // by marshmellow - demodulate NRZ wave - requires a read with strong signal
1222 // peaks invert bit (high=1 low=0) each clock cycle = 1 bit determined by last peak
1223 int nrzRawDemod ( uint8_t * dest
, size_t * size
, int * clk
, int * invert
){
1224 if ( justNoise ( dest
, * size
)) return - 1 ;
1225 * clk
= DetectNRZClock ( dest
, * size
, * clk
);
1226 if (* clk
== 0 ) return - 2 ;
1227 size_t i
, gLen
= 4096 ;
1228 if ( gLen
>* size
) gLen
= * size
- 20 ;
1230 if ( getHiLo ( dest
, gLen
, & high
, & low
, 75 , 75 ) < 1 ) return - 3 ; //25% fuzz on high 25% fuzz on low
1233 //convert wave samples to 1's and 0's
1234 for ( i
= 20 ; i
< * size
- 20 ; i
++){
1235 if ( dest
[ i
] >= high
) bit
= 1 ;
1236 if ( dest
[ i
] <= low
) bit
= 0 ;
1239 //now demod based on clock (rf/32 = 32 1's for one 1 bit, 32 0's for one 0 bit)
1242 for ( i
= 21 ; i
< * size
- 20 ; i
++) {
1243 //if transition detected or large number of same bits - store the passed bits
1244 if ( dest
[ i
] != dest
[ i
- 1 ] || ( i
- lastBit
) == ( 10 * * clk
)) {
1245 memset ( dest
+ numBits
, dest
[ i
- 1 ] ^ * invert
, ( i
- lastBit
+ (* clk
/ 4 )) / * clk
);
1246 numBits
+= ( i
- lastBit
+ (* clk
/ 4 )) / * clk
;
1255 //detects the bit clock for FSK given the high and low Field Clocks
1256 uint8_t detectFSKClk ( uint8_t * BitStream
, size_t size
, uint8_t fcHigh
, uint8_t fcLow
)
1258 uint8_t clk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 100 , 128 , 0 };
1259 uint16_t rfLens
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1260 uint8_t rfCnts
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1261 uint8_t rfLensFnd
= 0 ;
1262 uint8_t lastFCcnt
= 0 ;
1263 uint16_t fcCounter
= 0 ;
1264 uint16_t rfCounter
= 0 ;
1265 uint8_t firstBitFnd
= 0 ;
1267 if ( size
== 0 ) return 0 ;
1269 uint8_t fcTol
= (( fcHigh
* 100 - fcLow
* 100 )/ 2 + 50 )/ 100 ; //(uint8_t)(0.5+(float)(fcHigh-fcLow)/2);
1274 //PrintAndLog("DEBUG: fcTol: %d",fcTol);
1275 // prime i to first peak / up transition
1276 for ( i
= 160 ; i
< size
- 20 ; i
++)
1277 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
]>= BitStream
[ i
+ 1 ])
1280 for (; i
< size
- 20 ; i
++){
1284 if ( BitStream
[ i
] <= BitStream
[ i
- 1 ] || BitStream
[ i
] < BitStream
[ i
+ 1 ])
1287 // if we got less than the small fc + tolerance then set it to the small fc
1288 if ( fcCounter
< fcLow
+ fcTol
)
1290 else //set it to the large fc
1293 //look for bit clock (rf/xx)
1294 if (( fcCounter
< lastFCcnt
|| fcCounter
> lastFCcnt
)){
1295 //not the same size as the last wave - start of new bit sequence
1296 if ( firstBitFnd
> 1 ){ //skip first wave change - probably not a complete bit
1297 for ( int ii
= 0 ; ii
< 15 ; ii
++){
1298 if ( rfLens
[ ii
] >= ( rfCounter
- 4 ) && rfLens
[ ii
] <= ( rfCounter
+ 4 )){
1304 if ( rfCounter
> 0 && rfLensFnd
< 15 ){
1305 //PrintAndLog("DEBUG: rfCntr %d, fcCntr %d",rfCounter,fcCounter);
1306 rfCnts
[ rfLensFnd
]++;
1307 rfLens
[ rfLensFnd
++] = rfCounter
;
1313 lastFCcnt
= fcCounter
;
1317 uint8_t rfHighest
= 15 , rfHighest2
= 15 , rfHighest3
= 15 ;
1319 for ( i
= 0 ; i
< 15 ; i
++){
1320 //get highest 2 RF values (might need to get more values to compare or compare all?)
1321 if ( rfCnts
[ i
]> rfCnts
[ rfHighest
]){
1322 rfHighest3
= rfHighest2
;
1323 rfHighest2
= rfHighest
;
1325 } else if ( rfCnts
[ i
]> rfCnts
[ rfHighest2
]){
1326 rfHighest3
= rfHighest2
;
1328 } else if ( rfCnts
[ i
]> rfCnts
[ rfHighest3
]){
1331 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: RF %d, cnts %d" , rfLens
[ i
], rfCnts
[ i
]);
1333 // set allowed clock remainder tolerance to be 1 large field clock length+1
1334 // we could have mistakenly made a 9 a 10 instead of an 8 or visa versa so rfLens could be 1 FC off
1335 uint8_t tol1
= fcHigh
+ 1 ;
1337 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: most counted rf values: 1 %d, 2 %d, 3 %d" , rfLens
[ rfHighest
], rfLens
[ rfHighest2
], rfLens
[ rfHighest3
]);
1339 // loop to find the highest clock that has a remainder less than the tolerance
1340 // compare samples counted divided by
1341 // test 128 down to 32 (shouldn't be possible to have fc/10 & fc/8 and rf/16 or less)
1343 for (; ii
>= 2 ; ii
--){
1344 if ( rfLens
[ rfHighest
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1345 if ( rfLens
[ rfHighest2
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest2
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1346 if ( rfLens
[ rfHighest3
] % clk
[ ii
] < tol1
|| rfLens
[ rfHighest3
] % clk
[ ii
] > clk
[ ii
]- tol1
){
1347 if ( g_debugMode
== 2 ) prnt ( "DEBUG FSK: clk %d divides into the 3 most rf values within tolerance" , clk
[ ii
]);
1354 if ( ii
< 0 ) return 0 ; // oops we went too far
1360 //countFC is to detect the field clock lengths.
1361 //counts and returns the 2 most common wave lengths
1362 //mainly used for FSK field clock detection
1363 uint16_t countFC ( uint8_t * BitStream
, size_t size
, uint8_t fskAdj
)
1365 uint8_t fcLens
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1366 uint16_t fcCnts
[] = { 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 , 0 };
1367 uint8_t fcLensFnd
= 0 ;
1368 uint8_t lastFCcnt
= 0 ;
1369 uint8_t fcCounter
= 0 ;
1371 if ( size
== 0 ) return 0 ;
1373 // prime i to first up transition
1374 for ( i
= 160 ; i
< size
- 20 ; i
++)
1375 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
] >= BitStream
[ i
+ 1 ])
1378 for (; i
< size
- 20 ; i
++){
1379 if ( BitStream
[ i
] > BitStream
[ i
- 1 ] && BitStream
[ i
] >= BitStream
[ i
+ 1 ]){
1380 // new up transition
1383 //if we had 5 and now have 9 then go back to 8 (for when we get a fc 9 instead of an 8)
1384 if ( lastFCcnt
== 5 && fcCounter
== 9 ) fcCounter
--;
1385 //if fc=9 or 4 add one (for when we get a fc 9 instead of 10 or a 4 instead of a 5)
1386 if (( fcCounter
== 9 ) || fcCounter
== 4 ) fcCounter
++;
1387 // save last field clock count (fc/xx)
1388 lastFCcnt
= fcCounter
;
1390 // find which fcLens to save it to:
1391 for ( int ii
= 0 ; ii
< 15 ; ii
++){
1392 if ( fcLens
[ ii
]== fcCounter
){
1398 if ( fcCounter
> 0 && fcLensFnd
< 15 ){
1400 fcCnts
[ fcLensFnd
]++;
1401 fcLens
[ fcLensFnd
++]= fcCounter
;
1410 uint8_t best1
= 14 , best2
= 14 , best3
= 14 ;
1412 // go through fclens and find which ones are bigest 2
1413 for ( i
= 0 ; i
< 15 ; i
++){
1414 // get the 3 best FC values
1415 if ( fcCnts
[ i
]> maxCnt1
) {
1420 } else if ( fcCnts
[ i
]> fcCnts
[ best2
]){
1423 } else if ( fcCnts
[ i
]> fcCnts
[ best3
]){
1426 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
]);
1428 if ( fcLens
[ best1
]== 0 ) return 0 ;
1429 uint8_t fcH
= 0 , fcL
= 0 ;
1430 if ( fcLens
[ best1
]> fcLens
[ best2
]){
1437 if (( size
- 180 )/ fcH
/ 3 > fcCnts
[ best1
]+ fcCnts
[ best2
]) {
1438 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
]);
1439 return 0 ; //lots of waves not psk or fsk
1441 // TODO: take top 3 answers and compare to known Field clocks to get top 2
1443 uint16_t fcs
= ((( uint16_t ) fcH
)<< 8 ) | fcL
;
1444 if ( fskAdj
) return fcs
;
1445 return fcLens
[ best1
];
1448 //by marshmellow - demodulate PSK1 wave
1449 //uses wave lengths (# Samples)
1450 int pskRawDemod ( uint8_t dest
[], size_t * size
, int * clock
, int * invert
)
1452 if ( size
== 0 ) return - 1 ;
1453 uint16_t loopCnt
= 4096 ; //don't need to loop through entire array...
1454 if (* size
< loopCnt
) loopCnt
= * size
;
1457 uint8_t curPhase
= * invert
;
1458 size_t i
, waveStart
= 1 , waveEnd
= 0 , firstFullWave
= 0 , lastClkBit
= 0 ;
1459 uint8_t fc
= 0 , fullWaveLen
= 0 , tol
= 1 ;
1460 uint16_t errCnt
= 0 , waveLenCnt
= 0 ;
1461 fc
= countFC ( dest
, * size
, 0 );
1462 if ( fc
!= 2 && fc
!= 4 && fc
!= 8 ) return - 1 ;
1463 //PrintAndLog("DEBUG: FC: %d",fc);
1464 * clock
= DetectPSKClock ( dest
, * size
, * clock
);
1465 if (* clock
== 0 ) return - 1 ;
1466 int avgWaveVal
= 0 , lastAvgWaveVal
= 0 ;
1467 //find first phase shift
1468 for ( i
= 0 ; i
< loopCnt
; i
++){
1469 if ( dest
[ i
]+ fc
< dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1471 //PrintAndLog("DEBUG: waveEnd: %d",waveEnd);
1472 waveLenCnt
= waveEnd
- waveStart
;
1473 if ( waveLenCnt
> fc
&& waveStart
> fc
&& !( waveLenCnt
> fc
+ 2 )){ //not first peak and is a large wave but not out of whack
1474 lastAvgWaveVal
= avgWaveVal
/( waveLenCnt
);
1475 firstFullWave
= waveStart
;
1476 fullWaveLen
= waveLenCnt
;
1477 //if average wave value is > graph 0 then it is an up wave or a 1
1478 if ( lastAvgWaveVal
> 123 ) curPhase
^= 1 ; //fudge graph 0 a little 123 vs 128
1484 avgWaveVal
+= dest
[ i
+ 2 ];
1486 if ( firstFullWave
== 0 ) {
1487 // no phase shift detected - could be all 1's or 0's - doesn't matter where we start
1488 // so skip a little to ensure we are past any Start Signal
1489 firstFullWave
= 160 ;
1490 memset ( dest
, curPhase
, firstFullWave
/ * clock
);
1492 memset ( dest
, curPhase
^ 1 , firstFullWave
/ * clock
);
1495 numBits
+= ( firstFullWave
/ * clock
);
1496 //set start of wave as clock align
1497 lastClkBit
= firstFullWave
;
1498 //PrintAndLog("DEBUG: firstFullWave: %d, waveLen: %d",firstFullWave,fullWaveLen);
1499 //PrintAndLog("DEBUG: clk: %d, lastClkBit: %d", *clock, lastClkBit);
1501 dest
[ numBits
++] = curPhase
; //set first read bit
1502 for ( i
= firstFullWave
+ fullWaveLen
- 1 ; i
< * size
- 3 ; i
++){
1503 //top edge of wave = start of new wave
1504 if ( dest
[ i
]+ fc
< dest
[ i
+ 1 ] && dest
[ i
+ 1 ] >= dest
[ i
+ 2 ]){
1505 if ( waveStart
== 0 ) {
1508 avgWaveVal
= dest
[ i
+ 1 ];
1511 waveLenCnt
= waveEnd
- waveStart
;
1512 lastAvgWaveVal
= avgWaveVal
/ waveLenCnt
;
1513 if ( waveLenCnt
> fc
){
1514 //PrintAndLog("DEBUG: avgWaveVal: %d, waveSum: %d",lastAvgWaveVal,avgWaveVal);
1515 //this wave is a phase shift
1516 //PrintAndLog("DEBUG: phase shift at: %d, len: %d, nextClk: %d, i: %d, fc: %d",waveStart,waveLenCnt,lastClkBit+*clock-tol,i+1,fc);
1517 if ( i
+ 1 >= lastClkBit
+ * clock
- tol
){ //should be a clock bit
1519 dest
[ numBits
++] = curPhase
;
1520 lastClkBit
+= * clock
;
1521 } else if ( i
< lastClkBit
+ 10 + fc
){
1522 //noise after a phase shift - ignore
1523 } else { //phase shift before supposed to based on clock
1525 dest
[ numBits
++] = 7 ;
1527 } else if ( i
+ 1 > lastClkBit
+ * clock
+ tol
+ fc
){
1528 lastClkBit
+= * clock
; //no phase shift but clock bit
1529 dest
[ numBits
++] = curPhase
;
1535 avgWaveVal
+= dest
[ i
+ 1 ];
1542 //attempt to identify a Sequence Terminator in ASK modulated raw wave
1543 bool DetectST ( uint8_t buffer
[], size_t * size
, int * foundclock
) {
1544 size_t bufsize
= * size
;
1545 //need to loop through all samples and identify our clock, look for the ST pattern
1546 uint8_t fndClk
[] = { 8 , 16 , 32 , 40 , 50 , 64 , 128 };
1549 int i
, j
, skip
, start
, end
, low
, high
, minClk
, waveStart
;
1550 bool complete
= false ;
1551 int tmpbuff
[ bufsize
/ 64 ];
1552 int waveLen
[ bufsize
/ 64 ];
1553 size_t testsize
= ( bufsize
< 512 ) ? bufsize
: 512 ;
1556 memset ( tmpbuff
, 0 , sizeof ( tmpbuff
));
1558 if ( getHiLo ( buffer
, testsize
, & high
, & low
, 80 , 80 ) == - 1 ) {
1559 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: just noise detected - quitting" );
1560 return false ; //just noise
1565 // get to first full low to prime loop and skip incomplete first pulse
1566 while (( buffer
[ i
] < high
) && ( i
< bufsize
))
1568 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1572 // populate tmpbuff buffer with pulse lengths
1573 while ( i
< bufsize
) {
1574 // measure from low to low
1575 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1578 while (( buffer
[ i
] < high
) && ( i
< bufsize
))
1580 //first high point for this wave
1582 while (( buffer
[ i
] > low
) && ( i
< bufsize
))
1584 if ( j
>= ( bufsize
/ 64 )) {
1587 waveLen
[ j
] = i
- waveStart
; //first high to first low
1588 tmpbuff
[ j
++] = i
- start
;
1589 if ( i
- start
< minClk
&& i
< bufsize
) {
1593 // set clock - might be able to get this externally and remove this work...
1595 for ( uint8_t clkCnt
= 0 ; clkCnt
< 7 ; clkCnt
++) {
1596 tol
= fndClk
[ clkCnt
]/ 8 ;
1597 if ( minClk
>= fndClk
[ clkCnt
]- tol
&& minClk
<= fndClk
[ clkCnt
]+ 1 ) {
1602 // clock not found - ERROR
1604 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: clock not found - quitting" );
1611 // look for Sequence Terminator - should be pulses of clk*(1 or 1.5), clk*2, clk*(1.5 or 2)
1613 for ( i
= 0 ; i
< j
- 4 ; ++ i
) {
1615 if ( tmpbuff
[ i
] >= clk
* 1 - tol
&& tmpbuff
[ i
] <= ( clk
* 2 )+ tol
&& waveLen
[ i
] < clk
+ tol
) { //1 to 2 clocks depending on 2 bits prior
1616 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
1617 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
1618 if ( tmpbuff
[ i
+ 3 ] >= clk
* 1 - tol
&& tmpbuff
[ i
+ 3 ] <= clk
* 2 + tol
) { //1 to 2 clocks for end of ST + first bit
1626 // first ST not found - ERROR
1628 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: first STT not found - quitting" );
1631 if ( waveLen
[ i
+ 2 ] > clk
* 1 + tol
)
1636 // skip over the remainder of ST
1637 skip
+= clk
* 7 / 2 ; //3.5 clocks from tmpbuff[i] = end of st - also aligns for ending point
1639 // now do it again to find the end
1641 for ( i
+= 3 ; i
< j
- 4 ; ++ i
) {
1643 if ( tmpbuff
[ i
] >= clk
* 1 - tol
&& tmpbuff
[ i
] <= ( clk
* 2 )+ tol
) { //1 to 2 clocks depending on 2 bits prior
1644 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
1645 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
1646 if ( tmpbuff
[ i
+ 3 ] >= clk
* 1 - tol
&& tmpbuff
[ i
+ 3 ] <= clk
* 2 + tol
) { //1 to 2 clocks for end of ST + first bit
1655 //didn't find second ST - ERROR
1657 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: second STT not found - quitting" );
1660 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
);
1661 //now begin to trim out ST so we can use normal demod cmds
1663 size_t datalen
= end
- start
;
1664 // check validity of datalen (should be even clock increments) - use a tolerance of up to 1/8th a clock
1665 if ( datalen
% clk
> clk
/ 8 ) {
1666 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: datalen not divisible by clk: %u %% %d = %d - quitting" , datalen
, clk
, datalen
% clk
);
1669 // padd the amount off - could be problematic... but shouldn't happen often
1670 datalen
+= datalen
% clk
;
1672 // if datalen is less than one t55xx block - ERROR
1673 if ( datalen
/ clk
< 8 * 4 ) {
1674 if ( g_debugMode
== 2 ) prnt ( "DEBUG STT: datalen is less than 1 full t55xx block - quitting" );
1677 size_t dataloc
= start
;
1680 // warning - overwriting buffer given with raw wave data with ST removed...
1681 while ( dataloc
< bufsize
-( clk
/ 2 ) ) {
1682 //compensate for long high at end of ST not being high... (we cut out the high part)
1683 if ( buffer
[ dataloc
]< high
&& buffer
[ dataloc
]> low
&& buffer
[ dataloc
+ 3 ]< high
&& buffer
[ dataloc
+ 3 ]> low
) {
1684 for ( i
= 0 ; i
< clk
/ 2 - tol
; ++ i
) {
1685 buffer
[ dataloc
+ i
] = high
+ 5 ;
1688 for ( i
= 0 ; i
< datalen
; ++ i
) {
1689 if ( i
+ newloc
< bufsize
) {
1690 if ( i
+ newloc
< dataloc
)
1691 buffer
[ i
+ newloc
] = buffer
[ dataloc
];