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ISO15693 device side improvements (#652)

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* ISO15693 device side improvements
* increase accuracy by doubling the sample frequency (hi_read_rx_xcorr.v)
* adjust armsrc/iso15693.c and client/cmdhf15.c accordingly
* use more accurate approximation for sqrt(ci^2 + cq^2)
* improve EOF detection (was often mistaken for Logic0, resulting in "error, uneven octet! (extra bits!)")
* hi_read_r_xcorr.v: avoid overflows during accumulation and truncation
* explicitely cast unsigned ADC samples to signed
This commit is contained in:
pwpiwi 2018-08-15 14:03:20 +02:00 • committed by GitHub
commit 315e18e66c
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4 changed files with 174 additions and 130 deletions
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49
client/cmdhf15.c
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@ -268,7 +268,7 @@ static char* TagErrorStr(uint8_t error) {
case 0x02: return "The command is not recognised";
case 0x03: return "The option is not supported.";
case 0x0f: return "Unknown error.";
case 0x10: return "The specified block is not available (doesn’t exist).";
case 0x10: return "The specified block is not available (doesn't exist).";
case 0x11: return "The specified block is already -locked and thus cannot be locked again";
case 0x12: return "The specified block is locked and its content cannot be changed.";
case 0x13: return "The specified block was not successfully programmed.";
@ -286,12 +286,12 @@ int CmdHF15Demod(const char *Cmd)
int i, j;
int max = 0, maxPos = 0;
int skip = 4;
int skip = 2;
if (GraphTraceLen < 1000) return 0;
if (GraphTraceLen < 2000) return 0;
// First, correlate for SOF
for (i = 0; i < 100; i++) {
for (i = 0; i < 200; i++) {
int corr = 0;
for (j = 0; j < arraylen(FrameSOF); j += skip) {
corr += FrameSOF[j] * GraphBuffer[i + (j / skip)];
@ -310,23 +310,30 @@ int CmdHF15Demod(const char *Cmd)
memset(outBuf, 0, sizeof(outBuf));
uint8_t mask = 0x01;
for (;;) {
int corr0 = 0, corr1 = 0, corrEOF = 0;
for (j = 0; j < arraylen(Logic0); j += skip) {
corr0 += Logic0[j] * GraphBuffer[i + (j / skip)];
}
for (j = 0; j < arraylen(Logic1); j += skip) {
corr1 += Logic1[j] * GraphBuffer[i + (j / skip)];
}
for (j = 0; j < arraylen(FrameEOF); j += skip) {
corrEOF += FrameEOF[j] * GraphBuffer[i + (j / skip)];
}
// Even things out by the length of the target waveform.
corr0 *= 4;
corr1 *= 4;
if (corrEOF > corr1 && corrEOF > corr0) {
PrintAndLog("EOF at %d", i);
break;
int corr0 = 0, corr00 = 0, corr01 = 0, corr1 = 0, corrEOF = 0;
for(j = 0; j < arraylen(Logic0); j += skip) {
corr0 += Logic0[j]*GraphBuffer[i+(j/skip)];
}
corr01 = corr00 = corr0;
for(j = 0; j < arraylen(Logic0); j += skip) {
corr00 += Logic0[j]*GraphBuffer[i+arraylen(Logic0)/skip+(j/skip)];
corr01 += Logic1[j]*GraphBuffer[i+arraylen(Logic0)/skip+(j/skip)];
}
for(j = 0; j < arraylen(Logic1); j += skip) {
corr1 += Logic1[j]*GraphBuffer[i+(j/skip)];
}
for(j = 0; j < arraylen(FrameEOF); j += skip) {
corrEOF += FrameEOF[j]*GraphBuffer[i+(j/skip)];
}
// Even things out by the length of the target waveform.
corr00 *= 2;
corr01 *= 2;
corr0 *= 4;
corr1 *= 4;
if(corrEOF > corr1 && corrEOF > corr00 && corrEOF > corr01) {
PrintAndLog("EOF at %d", i);
break;
} else if (corr1 > corr0) {
i += arraylen(Logic1) / skip;
outBuf[k] |= mask;