f0cf62cd73
CHG: tab fixes in cmdlf.c and minor code clean up CHG: minor variable name change, printstatement in cmddata.c
751 lines
20 KiB
C
751 lines
20 KiB
C
//-----------------------------------------------------------------------------
|
|
// Copyright (C) 2014
|
|
//
|
|
// This code is licensed to you under the terms of the GNU GPL, version 2 or,
|
|
// at your option, any later version. See the LICENSE.txt file for the text of
|
|
// the license.
|
|
//-----------------------------------------------------------------------------
|
|
// Low frequency commands
|
|
//-----------------------------------------------------------------------------
|
|
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include "lfdemod.h"
|
|
|
|
//by marshmellow
|
|
//takes 1s and 0s and searches for EM410x format - output EM ID
|
|
uint64_t Em410xDecode(uint8_t *BitStream, uint32_t BitLen)
|
|
{
|
|
//no arguments needed - built this way in case we want this to be a direct call from "data " cmds in the future
|
|
// otherwise could be a void with no arguments
|
|
//set defaults
|
|
int high = 0, low = 128;
|
|
uint64_t lo = 0;
|
|
uint32_t i = 0;
|
|
uint32_t initLoopMax = 65;
|
|
|
|
if (initLoopMax > BitLen)
|
|
initLoopMax = BitLen;
|
|
|
|
for (; i < initLoopMax; ++i) //65 samples should be plenty to find high and low values
|
|
{
|
|
if (BitStream[i] > high)
|
|
high = BitStream[i];
|
|
else if (BitStream[i] < low)
|
|
low = BitStream[i];
|
|
}
|
|
|
|
if (((high !=1)||(low !=0))){ //allow only 1s and 0s
|
|
return 0;
|
|
}
|
|
|
|
uint8_t parityTest = 0;
|
|
// 111111111 bit pattern represent start of frame
|
|
uint8_t frame_marker_mask[] = {1,1,1,1,1,1,1,1,1};
|
|
uint32_t idx = 0;
|
|
uint32_t j = 0;
|
|
uint8_t resetCnt = 0;
|
|
while( (idx + 64) < BitLen) {
|
|
|
|
restart:
|
|
|
|
// search for a start of frame marker
|
|
if ( memcmp(BitStream+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0) {
|
|
// frame marker found
|
|
idx += 9;//sizeof(frame_marker_mask);
|
|
for ( i = 0; i < 10; ++i){
|
|
for( j = 0; j < 5; ++j){
|
|
parityTest += BitStream[(i*5) + j + idx];
|
|
}
|
|
if (parityTest == ( (parityTest >> 1) << 1)){
|
|
parityTest = 0;
|
|
for (j = 0; j < 4; ++j){
|
|
lo = ( lo << 1LL)|( BitStream[( i * 5 ) + j + idx]);
|
|
}
|
|
} else {
|
|
//parity failed
|
|
parityTest = 0;
|
|
idx -= 8;
|
|
if (resetCnt > 5) return 0;
|
|
resetCnt++;
|
|
goto restart;//continue;
|
|
}
|
|
}
|
|
//skip last 5 bit parity test for simplicity.
|
|
return lo;
|
|
} else {
|
|
idx++;
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
//by marshmellow
|
|
//takes 2 arguments - clock and invert both as integers
|
|
//attempts to demodulate ask while decoding manchester
|
|
//prints binary found and saves in graphbuffer for further commands
|
|
int askmandemod(uint8_t *BinStream, uint32_t *BitLen, int *clk, int *invert)
|
|
{
|
|
int i;
|
|
int high = 0, low = 128;
|
|
*clk = DetectASKClock(BinStream, (size_t)*BitLen, *clk); //clock default
|
|
|
|
if (*clk < 8 ) *clk = 64;
|
|
if (*clk < 32 ) *clk = 32;
|
|
if (*invert != 1) *invert = 0;
|
|
|
|
uint32_t initLoopMax = 200;
|
|
if (initLoopMax > *BitLen)
|
|
initLoopMax = *BitLen;
|
|
|
|
// Detect high and lows
|
|
// 200 samples should be enough to find high and low values
|
|
for (i = 0; i < initLoopMax; ++i) {
|
|
if (BinStream[i] > high)
|
|
high = BinStream[i];
|
|
else if (BinStream[i] < low)
|
|
low = BinStream[i];
|
|
}
|
|
|
|
//throw away static
|
|
if ((high < 158) )
|
|
return -2;
|
|
|
|
//25% fuzz in case highs and lows aren't clipped [marshmellow]
|
|
high = (int)(high * .75);
|
|
low = (int)(low+128 * .25);
|
|
|
|
int lastBit = 0; // set first clock check
|
|
uint32_t bitnum = 0; // output counter
|
|
|
|
// clock tolerance adjust - waves will be accepted as within the clock if they fall + or - this value + clock from last valid wave
|
|
//clock tolerance may not be needed anymore currently set to + or - 1 but could be increased for poor waves or removed entirely
|
|
int tol = ( *clk == 32 ) ? 1 : 0;
|
|
|
|
int j = 0;
|
|
uint32_t gLen = *BitLen;
|
|
|
|
if (gLen > 3000) gLen = 3000;
|
|
|
|
uint8_t errCnt = 0;
|
|
uint32_t bestStart = *BitLen;
|
|
uint32_t bestErrCnt = (*BitLen/1000);
|
|
uint32_t maxErr = bestErrCnt;
|
|
|
|
//loop to find first wave that works
|
|
for (j=0; j < gLen; ++j){
|
|
|
|
if ((BinStream[j] >= high)||(BinStream[j] <= low)){
|
|
lastBit = j - *clk;
|
|
errCnt = 0;
|
|
|
|
//loop through to see if this start location works
|
|
for (i = j; i < *BitLen; ++i) {
|
|
if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
|
|
lastBit += *clk;
|
|
} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
|
|
//low found and we are expecting a bar
|
|
lastBit += *clk;
|
|
} else {
|
|
//mid value found or no bar supposed to be here
|
|
if ((i-lastBit) > (*clk + tol)){
|
|
//should have hit a high or low based on clock!!
|
|
|
|
errCnt++;
|
|
lastBit += *clk;//skip over until hit too many errors
|
|
if (errCnt > maxErr) break; //allow 1 error for every 1000 samples else start over
|
|
}
|
|
}
|
|
if ((i-j) >(400 * *clk)) break; //got plenty of bits
|
|
}
|
|
//we got more than 64 good bits and not all errors
|
|
if ((((i-j)/ *clk) > (64 + errCnt)) && (errCnt < maxErr)) {
|
|
//possible good read
|
|
if (errCnt == 0){
|
|
bestStart = j;
|
|
bestErrCnt = errCnt;
|
|
break; //great read - finish
|
|
}
|
|
if (errCnt < bestErrCnt){ //set this as new best run
|
|
bestErrCnt = errCnt;
|
|
bestStart = j;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (bestErrCnt < maxErr){
|
|
//best run is good enough set to best run and set overwrite BinStream
|
|
j = bestStart;
|
|
lastBit = bestStart - *clk;
|
|
bitnum = 0;
|
|
for (i = j; i < *BitLen; ++i) {
|
|
if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
|
|
lastBit += *clk;
|
|
BinStream[bitnum] = *invert;
|
|
bitnum++;
|
|
} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
|
|
//low found and we are expecting a bar
|
|
lastBit += *clk;
|
|
BinStream[bitnum] = 1 - *invert;
|
|
bitnum++;
|
|
} else {
|
|
//mid value found or no bar supposed to be here
|
|
if ((i-lastBit) > (*clk+tol)){
|
|
//should have hit a high or low based on clock!!
|
|
if (bitnum > 0){
|
|
BinStream[bitnum] = 77;
|
|
bitnum++;
|
|
}
|
|
lastBit += *clk;//skip over error
|
|
}
|
|
}
|
|
if (bitnum >= 400) break;
|
|
}
|
|
*BitLen = bitnum;
|
|
} else {
|
|
*invert = bestStart;
|
|
*clk = j;
|
|
return -1;
|
|
}
|
|
return bestErrCnt;
|
|
}
|
|
|
|
//by marshmellow
|
|
//take 10 and 01 and manchester decode
|
|
//run through 2 times and take least errCnt
|
|
int manrawdecode(uint8_t * bits, int *bitlen)
|
|
{
|
|
int bitnum = 0;
|
|
int errCnt = 0;
|
|
int bestErr = 1000;
|
|
int bestRun = 0;
|
|
int i = 1;
|
|
int j = 1;
|
|
|
|
for (; j < 3; ++j){
|
|
i = 1;
|
|
for ( i = i + j; i < *bitlen-2; i += 2){
|
|
if ( bits[i]==1 && (bits[i+1]==0)){
|
|
} else if ((bits[i]==0)&& bits[i+1]==1){
|
|
} else {
|
|
errCnt++;
|
|
}
|
|
if(bitnum > 300) break;
|
|
}
|
|
if (bestErr > errCnt){
|
|
bestErr = errCnt;
|
|
bestRun = j;
|
|
}
|
|
errCnt = 0;
|
|
}
|
|
errCnt = bestErr;
|
|
if (errCnt < 20){
|
|
j = bestRun;
|
|
i = 1;
|
|
for ( i = i+j; i < *bitlen-2; i += 2){
|
|
if ( bits[i] == 1 && bits[i + 1] == 0 ){
|
|
bits[bitnum++] = 0;
|
|
} else if ( bits[i] == 0 && bits[i + 1] == 1 ){
|
|
bits[bitnum++] = 1;
|
|
} else {
|
|
bits[bitnum++] = 77;
|
|
}
|
|
if ( bitnum > 300 ) break;
|
|
}
|
|
*bitlen = bitnum;
|
|
}
|
|
return errCnt;
|
|
}
|
|
|
|
|
|
//by marshmellow
|
|
//take 01 or 10 = 0 and 11 or 00 = 1
|
|
int BiphaseRawDecode(uint8_t * bits, int *bitlen, int offset)
|
|
{
|
|
uint8_t bitnum = 0;
|
|
uint32_t errCnt = 0;
|
|
uint32_t i = offset;
|
|
|
|
for (; i < *bitlen-2; i += 2 ){
|
|
if ( (bits[i]==1 && bits[i+1]==0)||
|
|
(bits[i]==0 && bits[i+1]==1)){
|
|
bits[bitnum++] = 1;
|
|
} else if ( (bits[i]==0 && bits[i+1]==0)||
|
|
(bits[i]==1 && bits[i+1]==1)){
|
|
bits[bitnum++] = 0;
|
|
} else {
|
|
bits[bitnum++] = 77;
|
|
errCnt++;
|
|
}
|
|
if ( bitnum > 250) break;
|
|
}
|
|
*bitlen = bitnum;
|
|
return errCnt;
|
|
}
|
|
|
|
//by marshmellow
|
|
//takes 2 arguments - clock and invert both as integers
|
|
//attempts to demodulate ask only
|
|
//prints binary found and saves in graphbuffer for further commands
|
|
int askrawdemod(uint8_t *BinStream, int *bitLen, int *clk, int *invert)
|
|
{
|
|
uint32_t i;
|
|
uint32_t initLoopMax = 200;
|
|
int high = 0, low = 128;
|
|
uint8_t BitStream[502] = {0x00};
|
|
|
|
*clk = DetectASKClock(BinStream, *bitLen, *clk); //clock default
|
|
|
|
if (*clk < 8) *clk = 64;
|
|
if (*clk < 32) *clk = 32;
|
|
if (*invert != 1) *invert = 0;
|
|
|
|
if (initLoopMax > *bitLen)
|
|
initLoopMax = *bitLen;
|
|
|
|
// Detect high and lows
|
|
for (i = 0; i < initLoopMax; ++i) //200 samples should be plenty to find high and low values
|
|
{
|
|
if (BinStream[i] > high)
|
|
high = BinStream[i];
|
|
else if (BinStream[i] < low)
|
|
low = BinStream[i];
|
|
}
|
|
|
|
//throw away static
|
|
if ((high < 158)){
|
|
return -2;
|
|
}
|
|
|
|
//25% fuzz in case highs and lows aren't clipped [marshmellow]
|
|
high = (int)(high * .75);
|
|
low = (int)(low+128 * .25);
|
|
|
|
int lastBit = 0; //set first clock check
|
|
uint32_t bitnum = 0; //output counter
|
|
|
|
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
|
|
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
|
|
|
|
uint32_t gLen = *bitLen;
|
|
if (gLen > 500) gLen = 500;
|
|
|
|
uint32_t j = 0;
|
|
uint8_t errCnt = 0;
|
|
uint32_t bestStart = *bitLen;
|
|
uint32_t bestErrCnt = (*bitLen / 1000);
|
|
uint32_t errCntLimit = bestErrCnt;
|
|
uint8_t midBit = 0;
|
|
|
|
//loop to find first wave that works
|
|
for (j = 0; j < gLen; ++j){
|
|
|
|
if ((BinStream[j] >= high)||(BinStream[j] <= low)){
|
|
lastBit = j - *clk;
|
|
//loop through to see if this start location works
|
|
for (i = j; i < *bitLen; ++i) {
|
|
if ((BinStream[i] >= high) && ((i-lastBit)>(*clk-tol))){
|
|
lastBit += *clk;
|
|
BitStream[bitnum] = *invert;
|
|
bitnum++;
|
|
midBit = 0;
|
|
} else if ((BinStream[i] <= low) && ((i-lastBit)>(*clk-tol))){
|
|
//low found and we are expecting a bar
|
|
lastBit += *clk;
|
|
BitStream[bitnum] = 1-*invert;
|
|
bitnum++;
|
|
midBit=0;
|
|
} else if ((BinStream[i]<=low) && (midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
|
|
//mid bar?
|
|
midBit = 1;
|
|
BitStream[bitnum] = 1 - *invert;
|
|
bitnum++;
|
|
} else if ((BinStream[i]>=high)&&(midBit==0) && ((i-lastBit)>((*clk/2)-tol))){
|
|
//mid bar?
|
|
midBit = 1;
|
|
BitStream[bitnum] = *invert;
|
|
bitnum++;
|
|
} else if ((i-lastBit)>((*clk/2)+tol)&&(midBit==0)){
|
|
//no mid bar found
|
|
midBit = 1;
|
|
BitStream[bitnum] = BitStream[bitnum-1];
|
|
bitnum++;
|
|
} else {
|
|
//mid value found or no bar supposed to be here
|
|
|
|
if (( i - lastBit) > ( *clk + tol)){
|
|
//should have hit a high or low based on clock!!
|
|
|
|
if (bitnum > 0){
|
|
BitStream[bitnum] = 77;
|
|
bitnum++;
|
|
}
|
|
|
|
errCnt++;
|
|
lastBit += *clk;//skip over until hit too many errors
|
|
if (errCnt > errCntLimit){ //allow 1 error for every 1000 samples else start over
|
|
errCnt = 0;
|
|
bitnum = 0;//start over
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if (bitnum > 500) break;
|
|
}
|
|
//we got more than 64 good bits and not all errors
|
|
//possible good read
|
|
if ((bitnum > (64 + errCnt)) && (errCnt < errCntLimit)) {
|
|
|
|
//great read - finish
|
|
if (errCnt == 0) break;
|
|
|
|
//if current run == bestErrCnt run (after exhausted testing) then finish
|
|
if (bestStart == j) break;
|
|
|
|
//set this as new best run
|
|
if (errCnt < bestErrCnt){
|
|
bestErrCnt = errCnt;
|
|
bestStart = j;
|
|
}
|
|
}
|
|
}
|
|
if (j >= gLen){ //exhausted test
|
|
//if there was a ok test go back to that one and re-run the best run (then dump after that run)
|
|
if (bestErrCnt < errCntLimit)
|
|
j = bestStart;
|
|
}
|
|
}
|
|
if (bitnum > 16){
|
|
|
|
for (i = 0; i < bitnum; ++i){
|
|
BinStream[i] = BitStream[i];
|
|
}
|
|
*bitLen = bitnum;
|
|
} else {
|
|
return -1;
|
|
}
|
|
return errCnt;
|
|
}
|
|
//translate wave to 11111100000 (1 for each short wave 0 for each long wave)
|
|
size_t fsk_wave_demod(uint8_t * dest, size_t size, uint8_t fchigh, uint8_t fclow)
|
|
{
|
|
uint32_t last_transition = 0;
|
|
uint32_t idx = 1;
|
|
uint32_t maxVal = 0;
|
|
|
|
if (fchigh == 0) fchigh = 10;
|
|
if (fclow == 0) fclow = 8;
|
|
|
|
// we do care about the actual theshold value as sometimes near the center of the
|
|
// wave we may get static that changes direction of wave for one value
|
|
// if our value is too low it might affect the read. and if our tag or
|
|
// antenna is weak a setting too high might not see anything. [marshmellow]
|
|
if ( size < 100)
|
|
return 0;
|
|
|
|
// Find high from first 100 samples
|
|
for ( idx = 1; idx < 100; idx++ ){
|
|
if ( maxVal < dest[idx])
|
|
maxVal = dest[idx];
|
|
}
|
|
|
|
// set close to the top of the wave threshold with 25% margin for error
|
|
// less likely to get a false transition up there.
|
|
// (but have to be careful not to go too high and miss some short waves)
|
|
uint8_t threshold_value = (uint8_t)(maxVal * .75);
|
|
|
|
// sync to first lo-hi transition, and threshold
|
|
// Need to threshold first sample
|
|
|
|
dest[0] = (dest[0] < threshold_value) ? 0 : 1;
|
|
|
|
size_t numBits = 0;
|
|
|
|
// count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
|
|
// or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
|
|
// between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
|
|
for(idx = 1; idx < size; idx++) {
|
|
|
|
// threshold current value
|
|
dest[idx] = (dest[idx] < threshold_value) ? 0 : 1;
|
|
|
|
// Check for 0->1 transition
|
|
if (dest[idx-1] < dest[idx]) { // 0 -> 1 transition
|
|
if ( ( idx - last_transition ) <( fclow - 2 ) ) { //0-5 = garbage noise
|
|
//do nothing with extra garbage
|
|
} else if ((idx - last_transition) < ( fchigh - 1 )) { //6-8 = 8 waves
|
|
dest[numBits]=1;
|
|
} else { //9+ = 10 waves
|
|
dest[numBits]=0;
|
|
}
|
|
last_transition = idx;
|
|
numBits++;
|
|
}
|
|
}
|
|
//it returns the number of bytes, but each byte represents a bit: 1 or 0
|
|
return numBits;
|
|
}
|
|
|
|
uint32_t myround2(float f)
|
|
{
|
|
if (f >= 2000) return 2000;//something bad happened
|
|
return (uint32_t) (f + (float)0.5);
|
|
}
|
|
|
|
//translate 11111100000 to 10
|
|
size_t aggregate_bits(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t maxConsequtiveBits, uint8_t invert, uint8_t fchigh, uint8_t fclow )
|
|
{
|
|
uint8_t lastval = dest[0];
|
|
uint32_t idx = 0;
|
|
uint32_t n = 1;
|
|
size_t numBits = 0;
|
|
|
|
for( idx = 1; idx < size; idx++) {
|
|
|
|
if (dest[idx] == lastval) {
|
|
n++;
|
|
continue;
|
|
}
|
|
//if lastval was 1, we have a 1->0 crossing
|
|
if ( dest[idx-1] == 1 ) {
|
|
n = myround2( (float)( n + 1 ) / ((float)(rfLen)/(float)fclow));
|
|
} else { // 0->1 crossing
|
|
n = myround2( (float)( n + 1 ) / ((float)(rfLen-2)/(float)fchigh)); //-2 for fudge factor
|
|
}
|
|
if (n == 0) n = 1;
|
|
|
|
if(n < maxConsequtiveBits) //Consecutive
|
|
{
|
|
if(invert == 0){ //invert bits
|
|
memset(dest+numBits, dest[idx-1] , n);
|
|
}else{
|
|
memset(dest+numBits, dest[idx-1]^1 , n);
|
|
}
|
|
numBits += n;
|
|
}
|
|
n = 0;
|
|
lastval = dest[idx];
|
|
}//end for
|
|
return numBits;
|
|
}
|
|
|
|
//by marshmellow (from holiman's base)
|
|
// full fsk demod from GraphBuffer wave to decoded 1s and 0s (no mandemod)
|
|
int fskdemod(uint8_t *dest, size_t size, uint8_t rfLen, uint8_t invert, uint8_t fchigh, uint8_t fclow)
|
|
{
|
|
// FSK demodulator
|
|
size = fsk_wave_demod(dest, size, fchigh, fclow);
|
|
if ( size > 0 )
|
|
size = aggregate_bits(dest, size, rfLen, 192, invert, fchigh, fclow);
|
|
return size;
|
|
}
|
|
|
|
// loop to get raw HID waveform then FSK demodulate the TAG ID from it
|
|
int HIDdemodFSK(uint8_t *dest, size_t size, uint32_t *hi2, uint32_t *hi, uint32_t *lo)
|
|
{
|
|
size_t idx = 0;
|
|
int numshifts = 0;
|
|
|
|
// FSK demodulator
|
|
size = fskdemod(dest, size, 50, 0, 10, 8);
|
|
|
|
// final loop, go over previously decoded manchester data and decode into usable tag ID
|
|
// 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0
|
|
uint8_t frame_marker_mask[] = {1,1,1,0,0,0};
|
|
|
|
uint8_t mask_len = sizeof frame_marker_mask / sizeof frame_marker_mask[0];
|
|
|
|
//one scan
|
|
while( idx + mask_len < size) {
|
|
// search for a start of frame marker
|
|
if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
|
|
{ // frame marker found
|
|
idx += mask_len;
|
|
while(dest[idx] != dest[idx+1] && idx < size-2)
|
|
{
|
|
// Keep going until next frame marker (or error)
|
|
// Shift in a bit. Start by shifting high registers
|
|
*hi2 = ( *hi2 << 1 ) | ( *hi >> 31 );
|
|
*hi = ( *hi << 1 ) | ( *lo >> 31 );
|
|
//Then, shift in a 0 or one into low
|
|
if (dest[idx] && !dest[idx+1]) // 1 0
|
|
*lo = ( *lo << 1 ) | 0;
|
|
else // 0 1
|
|
*lo = ( *lo << 1 ) | 1;
|
|
numshifts++;
|
|
idx += 2;
|
|
}
|
|
// Hopefully, we read a tag and hit upon the next frame marker
|
|
if(idx + mask_len < size)
|
|
{
|
|
if ( memcmp(dest+idx, frame_marker_mask, sizeof(frame_marker_mask)) == 0)
|
|
{
|
|
//good return
|
|
return idx;
|
|
}
|
|
}
|
|
// reset
|
|
*hi2 = *hi = *lo = 0;
|
|
numshifts = 0;
|
|
}else {
|
|
idx++;
|
|
}
|
|
}
|
|
return -1;
|
|
}
|
|
|
|
uint32_t bytebits_to_byte(uint8_t *src, int numbits)
|
|
{
|
|
//HACK: potential overflow in numbits is larger then uint32 bits.
|
|
|
|
uint32_t num = 0;
|
|
for(int i = 0 ; i < numbits ; ++i) {
|
|
num = (num << 1) | (*src);
|
|
src++;
|
|
}
|
|
return num;
|
|
}
|
|
|
|
int IOdemodFSK(uint8_t *dest, size_t size)
|
|
{
|
|
//make sure buffer has data
|
|
if (size < 100) return -1;
|
|
|
|
uint32_t idx = 0;
|
|
uint8_t testMax = 0;
|
|
|
|
//test samples are not just noise
|
|
for (; idx < 65; ++idx ){
|
|
if (testMax < dest[idx])
|
|
testMax = dest[idx];
|
|
}
|
|
|
|
//if not just noise
|
|
if (testMax < 170) return -2;
|
|
|
|
// FSK demodulator
|
|
size = fskdemod(dest, size, 64, 1, 10, 8); // RF/64 and invert
|
|
|
|
//did we get a good demod?
|
|
if (size < 65) return -3;
|
|
|
|
//Index map
|
|
//0 10 20 30 40 50 60
|
|
//| | | | | | |
|
|
//01234567 8 90123456 7 89012345 6 78901234 5 67890123 4 56789012 3 45678901 23
|
|
//-----------------------------------------------------------------------------
|
|
//00000000 0 11110000 1 facility 1 version* 1 code*one 1 code*two 1 ???????? 11
|
|
//
|
|
//XSF(version)facility:codeone+codetwo
|
|
//Handle the data
|
|
|
|
uint8_t mask[] = {0,0,0,0,0,0,0,0,0,1};
|
|
|
|
for( idx = 0; idx < (size - 65); ++idx) {
|
|
if ( memcmp(dest + idx, mask, sizeof(mask))==0) {
|
|
//frame marker found
|
|
if (!dest[idx+8] &&
|
|
dest[idx+17] == 1 &&
|
|
dest[idx+26] == 1 &&
|
|
dest[idx+35] == 1 &&
|
|
dest[idx+44] == 1 &&
|
|
dest[idx+53] == 1){
|
|
//confirmed proper separator bits found
|
|
//return start position
|
|
return (int) idx;
|
|
}
|
|
}
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
// by marshmellow
|
|
// not perfect especially with lower clocks or VERY good antennas (heavy wave clipping)
|
|
// maybe somehow adjust peak trimming value based on samples to fix?
|
|
int DetectASKClock(uint8_t dest[], size_t size, int clock)
|
|
{
|
|
int i = 0;
|
|
int clk[] = {16,32,40,50,64,100,128,256};
|
|
uint8_t clkLen = sizeof clk / sizeof clk[0];
|
|
|
|
//if we already have a valid clock quit
|
|
for (; i < clkLen; ++i)
|
|
if (clk[i] == clock)
|
|
return clock;
|
|
|
|
int peak = 0;
|
|
int low = 128;
|
|
int loopCnt = 256;
|
|
if (size < loopCnt)
|
|
loopCnt = size;
|
|
|
|
//get high and low peak
|
|
for ( i = 0; i < loopCnt; ++i ){
|
|
if(dest[i] > peak)
|
|
peak = dest[i];
|
|
if(dest[i] < low)
|
|
low = dest[i];
|
|
}
|
|
|
|
peak = (int)(peak * .75);
|
|
low = (int)(low+128 * .25);
|
|
|
|
int ii, cnt, bestErr, tol = 0;
|
|
int errCnt[clkLen];
|
|
memset(errCnt, 0x00, clkLen);
|
|
|
|
int tmpIndex, tmphigh, tmplow;
|
|
|
|
//test each valid clock from smallest to greatest to see which lines up
|
|
for( cnt = 0; cnt < clkLen; ++cnt ){
|
|
|
|
tol = (clk[cnt] == 32) ? 1 : 0;
|
|
bestErr = 1000;
|
|
tmpIndex = tmphigh = tmplow = 0;
|
|
|
|
//try lining up the peaks by moving starting point (try first 256)
|
|
for (ii=0; ii < loopCnt; ++ii){
|
|
|
|
// not a peak? continue
|
|
if ( (dest[ii] < peak) && (dest[ii] > low))
|
|
continue;
|
|
|
|
errCnt[cnt] = 0;
|
|
|
|
// now that we have the first one lined up test rest of wave array
|
|
for ( i = 0; i < ((int)(size / clk[cnt]) - 1); ++i){
|
|
|
|
tmpIndex = ii + (i * clk[cnt] );
|
|
tmplow = dest[ tmpIndex - tol];
|
|
tmphigh = dest[ tmpIndex + tol];
|
|
|
|
if ( dest[tmpIndex] >= peak || dest[tmpIndex] <= low ) {
|
|
}
|
|
else if ( tmplow >= peak || tmplow <= low){
|
|
}
|
|
else if ( tmphigh >= peak || tmphigh <= low){
|
|
}
|
|
else
|
|
errCnt[cnt]++; //error no peak detected
|
|
}
|
|
|
|
//if we found no errors this is correct one - return this clock
|
|
if ( errCnt[cnt] == 0 )
|
|
return clk[cnt];
|
|
|
|
if ( errCnt[cnt] < bestErr)
|
|
bestErr = errCnt[cnt];
|
|
}
|
|
// save the least error.
|
|
errCnt[cnt] = bestErr;
|
|
}
|
|
// find best clock which has lowest number of errors
|
|
int j = 0, bestIndex = 0;
|
|
for (; j < clkLen; ++j){
|
|
if ( errCnt[j] < errCnt[bestIndex] )
|
|
bestIndex = j;
|
|
}
|
|
return clk[bestIndex];
|
|
}
|