fixing iso14443b (issue ):

- fix: IQ demodulator (FPGA)
- fix: approximately align reader signal delay to tag response delay (FPGA)
- fix: remove deprecated RSSI calculation to improve decoder speed (iso14443b.c)
- fix: better approximation of signal amplitude to avoid false carrier detection (iso14443b.c)
- fix: remove initial power off in iso14443b raw command (iso14443b.c)
- add: enable tracing for iso14443b raw command (iso14443b.c)
- fix: client crashed when checking CRC for incomplete responses (iso14433b.c)
- speeding up snoop to avoid circular buffer overflow
- added some comments for better documentation
- rename functions (iso14443 -> iso14443b)
- remove unused code in hi_read_rx_xcorr.v
This commit is contained in:
pwpiwi 2015-06-12 07:43:00 +02:00
parent 09c66f1f09
commit 51d4f6f114
7 changed files with 279 additions and 320 deletions

View file

@ -263,7 +263,7 @@ void SimulateTagHfListen(void)
// We're using this mode just so that I can test it out; the simulated
// tag mode would work just as well and be simpler.
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | FPGA_HF_READER_RX_XCORR_SNOOP);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_SNOOP);
// We need to listen to the high-frequency, peak-detected path.
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
@ -783,19 +783,19 @@ void UsbPacketReceived(uint8_t *packet, int len)
#ifdef WITH_ISO14443b
case CMD_ACQUIRE_RAW_ADC_SAMPLES_ISO_14443:
AcquireRawAdcSamplesIso14443(c->arg[0]);
AcquireRawAdcSamplesIso14443b(c->arg[0]);
break;
case CMD_READ_SRI512_TAG:
ReadSTMemoryIso14443(0x0F);
ReadSTMemoryIso14443b(0x0F);
break;
case CMD_READ_SRIX4K_TAG:
ReadSTMemoryIso14443(0x7F);
ReadSTMemoryIso14443b(0x7F);
break;
case CMD_SNOOP_ISO_14443:
SnoopIso14443();
SnoopIso14443b();
break;
case CMD_SIMULATE_TAG_ISO_14443:
SimulateIso14443Tag();
SimulateIso14443bTag();
break;
case CMD_ISO_14443B_COMMAND:
SendRawCommand14443B(c->arg[0],c->arg[1],c->arg[2],c->d.asBytes);

View file

@ -141,10 +141,10 @@ void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode);
void EM4xWriteWord(uint32_t Data, uint8_t Address, uint32_t Pwd, uint8_t PwdMode);
/// iso14443.h
void SimulateIso14443Tag(void);
void AcquireRawAdcSamplesIso14443(uint32_t parameter);
void ReadSTMemoryIso14443(uint32_t);
void RAMFUNC SnoopIso14443(void);
void SimulateIso14443bTag(void);
void AcquireRawAdcSamplesIso14443b(uint32_t parameter);
void ReadSTMemoryIso14443b(uint32_t);
void RAMFUNC SnoopIso14443b(void);
void SendRawCommand14443B(uint32_t, uint32_t, uint8_t, uint8_t[]);
/// iso14443a.h

View file

@ -5,9 +5,8 @@
// at your option, any later version. See the LICENSE.txt file for the text of
// the license.
//-----------------------------------------------------------------------------
// Routines to support ISO 14443. This includes both the reader software and
// the `fake tag' modes. At the moment only the Type B modulation is
// supported.
// Routines to support ISO 14443B. This includes both the reader software and
// the `fake tag' modes.
//-----------------------------------------------------------------------------
#include "proxmark3.h"
@ -17,15 +16,8 @@
#include "iso14443crc.h"
//static void GetSamplesFor14443(int weTx, int n);
/*#define DEMOD_TRACE_SIZE 4096
#define READER_TAG_BUFFER_SIZE 2048
#define TAG_READER_BUFFER_SIZE 2048
#define DEMOD_DMA_BUFFER_SIZE 1024
*/
#define RECEIVE_SAMPLES_TIMEOUT 2000
#define ISO14443B_DMA_BUFFER_SIZE 512
//=============================================================================
// An ISO 14443 Type B tag. We listen for commands from the reader, using
@ -104,14 +96,14 @@ static void CodeIso14443bAsTag(const uint8_t *cmd, int len)
ToSendStuffBit(1);
}
// Send SOF.
// Send EOF.
for(i = 0; i < 10; i++) {
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
ToSendStuffBit(0);
}
for(i = 0; i < 10; i++) {
for(i = 0; i < 2; i++) {
ToSendStuffBit(1);
ToSendStuffBit(1);
ToSendStuffBit(1);
@ -120,9 +112,6 @@ static void CodeIso14443bAsTag(const uint8_t *cmd, int len)
// Convert from last byte pos to length
ToSendMax++;
// Add a few more for slop
ToSendMax += 2;
}
//-----------------------------------------------------------------------------
@ -146,6 +135,9 @@ static struct {
} Uart;
/* Receive & handle a bit coming from the reader.
*
* This function is called 4 times per bit (every 2 subcarrier cycles).
* Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us
*
* LED handling:
* LED A -> ON once we have received the SOF and are expecting the rest.
@ -154,7 +146,7 @@ static struct {
* Returns: true if we received a EOF
* false if we are still waiting for some more
*/
static int Handle14443UartBit(int bit)
static int Handle14443bUartBit(int bit)
{
switch(Uart.state) {
case STATE_UNSYNCD:
@ -169,9 +161,9 @@ static int Handle14443UartBit(int bit)
case STATE_GOT_FALLING_EDGE_OF_SOF:
Uart.posCnt++;
if(Uart.posCnt == 2) {
if(Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit
if(bit) {
if(Uart.bitCnt >= 10) {
if(Uart.bitCnt > 9) {
// we've seen enough consecutive
// zeros that it's a valid SOF
Uart.posCnt = 0;
@ -189,7 +181,7 @@ static int Handle14443UartBit(int bit)
Uart.bitCnt++;
}
if(Uart.posCnt >= 4) Uart.posCnt = 0;
if(Uart.bitCnt > 14) {
if(Uart.bitCnt > 12) {
// Give up if we see too many zeros without
// a one, too.
Uart.state = STATE_ERROR_WAIT;
@ -199,7 +191,7 @@ static int Handle14443UartBit(int bit)
case STATE_AWAITING_START_BIT:
Uart.posCnt++;
if(bit) {
if(Uart.posCnt > 25) {
if(Uart.posCnt > 50/2) { // max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
// stayed high for too long between
// characters, error
Uart.state = STATE_ERROR_WAIT;
@ -283,12 +275,12 @@ static int Handle14443UartBit(int bit)
// Assume that we're called with the SSC (to the FPGA) and ADC path set
// correctly.
//-----------------------------------------------------------------------------
static int GetIso14443CommandFromReader(uint8_t *received, int *len, int maxLen)
static int GetIso14443bCommandFromReader(uint8_t *received, int *len, int maxLen)
{
uint8_t mask;
int i, bit;
// Set FPGA mode to "simulated ISO 14443 tag", no modulation (listen
// Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
// only, since we are receiving, not transmitting).
// Signal field is off with the appropriate LED
LED_D_OFF();
@ -314,7 +306,7 @@ static int GetIso14443CommandFromReader(uint8_t *received, int *len, int maxLen)
mask = 0x80;
for(i = 0; i < 8; i++, mask >>= 1) {
bit = (b & mask);
if(Handle14443UartBit(bit)) {
if(Handle14443bUartBit(bit)) {
*len = Uart.byteCnt;
return TRUE;
}
@ -327,9 +319,13 @@ static int GetIso14443CommandFromReader(uint8_t *received, int *len, int maxLen)
// Main loop of simulated tag: receive commands from reader, decide what
// response to send, and send it.
//-----------------------------------------------------------------------------
void SimulateIso14443Tag(void)
void SimulateIso14443bTag(void)
{
// the only command we understand is REQB, AFI=0, Select All, N=0:
static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
// ... and we respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
// supports only 106kBit/s in both directions, max frame size = 32Bytes,
// supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
static const uint8_t response1[] = {
0x50, 0x82, 0x0d, 0xe1, 0x74, 0x20, 0x38, 0x19, 0x22,
0x00, 0x21, 0x85, 0x5e, 0xd7
@ -338,10 +334,9 @@ void SimulateIso14443Tag(void)
uint8_t *resp;
int respLen;
uint8_t *resp1 = BigBuf_get_addr() + 800;
int resp1Len;
uint8_t *receivedCmd = BigBuf_get_addr();
// allocate command receive buffer
BigBuf_free();
uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
int len;
int i;
@ -349,10 +344,12 @@ void SimulateIso14443Tag(void)
int cmdsRecvd = 0;
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
memset(receivedCmd, 0x44, 400);
// prepare the (only one) tag answer:
CodeIso14443bAsTag(response1, sizeof(response1));
memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax;
uint8_t *resp1 = BigBuf_malloc(ToSendMax);
memcpy(resp1, ToSend, ToSendMax);
uint16_t resp1Len = ToSendMax;
// We need to listen to the high-frequency, peak-detected path.
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
@ -363,14 +360,14 @@ void SimulateIso14443Tag(void)
for(;;) {
uint8_t b1, b2;
if(!GetIso14443CommandFromReader(receivedCmd, &len, 100)) {
Dbprintf("button pressed, received %d commands", cmdsRecvd);
break;
}
if(!GetIso14443bCommandFromReader(receivedCmd, &len, 100)) {
Dbprintf("button pressed, received %d commands", cmdsRecvd);
break;
}
// Good, look at the command now.
if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len)==0) {
if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0) {
resp = resp1; respLen = resp1Len;
} else {
Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
@ -385,8 +382,6 @@ void SimulateIso14443Tag(void)
break;
}
memset(receivedCmd, 0x44, 32);
cmdsRecvd++;
if(cmdsRecvd > 0x30) {
@ -444,8 +439,10 @@ static struct {
int bitCount;
int posCount;
int thisBit;
/* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
int metric;
int metricN;
*/
uint16_t shiftReg;
uint8_t *output;
int len;
@ -456,6 +453,9 @@ static struct {
/*
* Handles reception of a bit from the tag
*
* This function is called 2 times per bit (every 4 subcarrier cycles).
* Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 4,72us
*
* LED handling:
* LED C -> ON once we have received the SOF and are expecting the rest.
* LED C -> OFF once we have received EOF or are unsynced
@ -464,12 +464,12 @@ static struct {
* false if we are still waiting for some more
*
*/
static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
static RAMFUNC int Handle14443bSamplesDemod(int ci, int cq)
{
int v;
// The soft decision on the bit uses an estimate of just the
// quadrant of the reference angle, not the exact angle.
// The soft decision on the bit uses an estimate of just the
// quadrant of the reference angle, not the exact angle.
#define MAKE_SOFT_DECISION() { \
if(Demod.sumI > 0) { \
v = ci; \
@ -483,47 +483,87 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
} \
}
#define SUBCARRIER_DETECT_THRESHOLD 8
// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by abs(ci) + abs(cq)
/* #define CHECK_FOR_SUBCARRIER() { \
v = ci; \
if(v < 0) v = -v; \
if(cq > 0) { \
v += cq; \
} else { \
v -= cq; \
} \
}
*/
// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
#define CHECK_FOR_SUBCARRIER() { \
if(ci < 0) { \
if(cq < 0) { /* ci < 0, cq < 0 */ \
if (cq < ci) { \
v = -cq - (ci >> 1); \
} else { \
v = -ci - (cq >> 1); \
} \
} else { /* ci < 0, cq >= 0 */ \
if (cq < -ci) { \
v = -ci + (cq >> 1); \
} else { \
v = cq - (ci >> 1); \
} \
} \
} else { \
if(cq < 0) { /* ci >= 0, cq < 0 */ \
if (-cq < ci) { \
v = ci - (cq >> 1); \
} else { \
v = -cq + (ci >> 1); \
} \
} else { /* ci >= 0, cq >= 0 */ \
if (cq < ci) { \
v = ci + (cq >> 1); \
} else { \
v = cq + (ci >> 1); \
} \
} \
} \
}
switch(Demod.state) {
case DEMOD_UNSYNCD:
v = ci;
if(v < 0) v = -v;
if(cq > 0) {
v += cq;
} else {
v -= cq;
}
if(v > 40) {
Demod.posCount = 0;
CHECK_FOR_SUBCARRIER();
if(v > SUBCARRIER_DETECT_THRESHOLD) { // subcarrier detected
Demod.state = DEMOD_PHASE_REF_TRAINING;
Demod.sumI = 0;
Demod.sumQ = 0;
}
Demod.sumI = ci;
Demod.sumQ = cq;
Demod.posCount = 1;
}
break;
case DEMOD_PHASE_REF_TRAINING:
if(Demod.posCount < 8) {
Demod.sumI += ci;
Demod.sumQ += cq;
} else if(Demod.posCount > 100) {
// error, waited too long
Demod.state = DEMOD_UNSYNCD;
} else {
MAKE_SOFT_DECISION();
if(v < 0) {
Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
Demod.posCount = 0;
CHECK_FOR_SUBCARRIER();
if (v > SUBCARRIER_DETECT_THRESHOLD) {
// set the reference phase (will code a logic '1') by averaging over 32 1/fs.
// note: synchronization time > 80 1/fs
Demod.sumI += ci;
Demod.sumQ += cq;
Demod.posCount++;
} else { // subcarrier lost
Demod.state = DEMOD_UNSYNCD;
}
} else {
Demod.state = DEMOD_AWAITING_FALLING_EDGE_OF_SOF;
}
Demod.posCount++;
break;
case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
MAKE_SOFT_DECISION();
if(v < 0) {
if(v < 0) { // logic '0' detected
Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
Demod.posCount = 0;
Demod.posCount = 0; // start of SOF sequence
} else {
if(Demod.posCount > 100) {
if(Demod.posCount > 200/4) { // maximum length of TR1 = 200 1/fs
Demod.state = DEMOD_UNSYNCD;
}
}
@ -531,37 +571,40 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
break;
case DEMOD_GOT_FALLING_EDGE_OF_SOF:
Demod.posCount++;
MAKE_SOFT_DECISION();
if(v > 0) {
if(Demod.posCount < 12) {
if(Demod.posCount < 9*2) { // low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
Demod.state = DEMOD_UNSYNCD;
} else {
LED_C_ON(); // Got SOF
Demod.state = DEMOD_AWAITING_START_BIT;
Demod.posCount = 0;
Demod.len = 0;
/* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
Demod.metricN = 0;
Demod.metric = 0;
*/
}
} else {
if(Demod.posCount > 100) {
if(Demod.posCount > 12*2) { // low phase of SOF too long (> 12 etu)
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
}
}
Demod.posCount++;
break;
case DEMOD_AWAITING_START_BIT:
Demod.posCount++;
MAKE_SOFT_DECISION();
if(v > 0) {
if(Demod.posCount > 10) {
if(Demod.posCount > 3*2) { // max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
}
} else {
} else { // start bit detected
Demod.bitCount = 0;
Demod.posCount = 1;
Demod.posCount = 1; // this was the first half
Demod.thisBit = v;
Demod.shiftReg = 0;
Demod.state = DEMOD_RECEIVING_DATA;
@ -570,28 +613,30 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
case DEMOD_RECEIVING_DATA:
MAKE_SOFT_DECISION();
if(Demod.posCount == 0) {
if(Demod.posCount == 0) { // first half of bit
Demod.thisBit = v;
Demod.posCount = 1;
} else {
} else { // second half of bit
Demod.thisBit += v;
/* this had been used to add RSSI (Received Signal Strength Indication) to traces. Currently not implemented.
if(Demod.thisBit > 0) {
Demod.metric += Demod.thisBit;
} else {
Demod.metric -= Demod.thisBit;
}
(Demod.metricN)++;
*/
Demod.shiftReg >>= 1;
if(Demod.thisBit > 0) {
if(Demod.thisBit > 0) { // logic '1'
Demod.shiftReg |= 0x200;
}
Demod.bitCount++;
if(Demod.bitCount == 10) {
uint16_t s = Demod.shiftReg;
if((s & 0x200) && !(s & 0x001)) {
if((s & 0x200) && !(s & 0x001)) { // stop bit == '1', start bit == '0'
uint8_t b = (s >> 1);
Demod.output[Demod.len] = b;
Demod.len++;
@ -600,7 +645,7 @@ static RAMFUNC int Handle14443SamplesDemod(int ci, int cq)
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
if(s == 0x000) {
// This is EOF
// This is EOF (start, stop and all data bits == '0'
return TRUE;
}
}
@ -624,6 +669,7 @@ static void DemodReset()
// Clear out the state of the "UART" that receives from the tag.
Demod.len = 0;
Demod.state = DEMOD_UNSYNCD;
Demod.posCount = 0;
memset(Demod.output, 0x00, MAX_FRAME_SIZE);
}
@ -653,14 +699,12 @@ static void UartInit(uint8_t *data)
/*
* Demodulate the samples we received from the tag, also log to tracebuffer
* weTx: set to 'TRUE' if we behave like a reader
* set to 'FALSE' if we behave like a snooper
* quiet: set to 'TRUE' to disable debug output
*/
static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
static void GetSamplesFor14443bDemod(int n, bool quiet)
{
int max = 0;
int gotFrame = FALSE;
bool gotFrame = FALSE;
int lastRxCounter, ci, cq, samples = 0;
// Allocate memory from BigBuf for some buffers
@ -671,57 +715,56 @@ static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
// The DMA buffer, used to stream samples from the FPGA
int8_t *dmaBuf = (int8_t*) BigBuf_malloc(DMA_BUFFER_SIZE);
int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
// Set up the demodulator for tag -> reader responses.
DemodInit(receivedResponse);
// Setup and start DMA.
FpgaSetupSscDma((uint8_t*) dmaBuf, DMA_BUFFER_SIZE);
FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);
int8_t *upTo = dmaBuf;
lastRxCounter = DMA_BUFFER_SIZE;
lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
// Signal field is ON with the appropriate LED:
if (weTx) LED_D_ON(); else LED_D_OFF();
LED_D_ON();
// And put the FPGA in the appropriate mode
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
(weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
for(;;) {
int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
if(behindBy > max) max = behindBy;
while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (DMA_BUFFER_SIZE-1))
> 2)
{
while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (ISO14443B_DMA_BUFFER_SIZE-1)) > 2) {
ci = upTo[0];
cq = upTo[1];
upTo += 2;
if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
upTo = dmaBuf;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
}
lastRxCounter -= 2;
if(lastRxCounter <= 0) {
lastRxCounter += DMA_BUFFER_SIZE;
lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
}
samples += 2;
if(Handle14443SamplesDemod(ci, cq)) {
gotFrame = 1;
if(Handle14443bSamplesDemod(ci, cq)) {
gotFrame = TRUE;
break;
}
}
if(samples > n) {
if(samples > n || gotFrame) {
break;
}
}
AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
if (!quiet) Dbprintf("%x %x %x", max, gotFrame, Demod.len);
if (!quiet) Dbprintf("max behindby = %d, samples = %d, gotFrame = %d, Demod.len = %d, Demod.sumI = %d, Demod.sumQ = %d", max, samples, gotFrame, Demod.len, Demod.sumI, Demod.sumQ);
//Tracing
if (tracing && Demod.len > 0) {
uint8_t parity[MAX_PARITY_SIZE];
@ -731,43 +774,10 @@ static void GetSamplesFor14443Demod(int weTx, int n, int quiet)
}
//-----------------------------------------------------------------------------
// Read the tag's response. We just receive a stream of slightly-processed
// samples from the FPGA, which we will later do some signal processing on,
// to get the bits.
//-----------------------------------------------------------------------------
/*static void GetSamplesFor14443(int weTx, int n)
{
uint8_t *dest = (uint8_t *)BigBuf;
int c;
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
(weTx ? 0 : FPGA_HF_READER_RX_XCORR_SNOOP));
c = 0;
for(;;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0x43;
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
int8_t b;
b = (int8_t)AT91C_BASE_SSC->SSC_RHR;
dest[c++] = (uint8_t)b;
if(c >= n) {
break;
}
}
}
}*/
//-----------------------------------------------------------------------------
// Transmit the command (to the tag) that was placed in ToSend[].
//-----------------------------------------------------------------------------
static void TransmitFor14443(void)
static void TransmitFor14443b(void)
{
int c;
@ -781,8 +791,7 @@ static void TransmitFor14443(void)
LED_D_ON();
// Signal we are transmitting with the Green LED
LED_B_ON();
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
for(c = 0; c < 10;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
@ -817,7 +826,7 @@ static void TransmitFor14443(void)
//-----------------------------------------------------------------------------
// Code a layer 2 command (string of octets, including CRC) into ToSend[],
// so that it is ready to transmit to the tag using TransmitFor14443().
// so that it is ready to transmit to the tag using TransmitFor14443b().
//-----------------------------------------------------------------------------
static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
{
@ -873,16 +882,16 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
//-----------------------------------------------------------------------------
// Read an ISO 14443 tag. We send it some set of commands, and record the
// Read an ISO 14443B tag. We send it some set of commands, and record the
// responses.
// The command name is misleading, it actually decodes the reponse in HEX
// into the output buffer (read the result using hexsamples, not hisamples)
//
// obsolete function only for test
//-----------------------------------------------------------------------------
void AcquireRawAdcSamplesIso14443(uint32_t parameter)
void AcquireRawAdcSamplesIso14443b(uint32_t parameter)
{
uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 }; // REQB with AFI=0, Request All, N=0
SendRawCommand14443B(sizeof(cmd1),1,1,cmd1);
}
@ -894,7 +903,7 @@ void AcquireRawAdcSamplesIso14443(uint32_t parameter)
static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
{
CodeIso14443bAsReader(cmd, len);
TransmitFor14443();
TransmitFor14443b();
if (tracing) {
uint8_t parity[MAX_PARITY_SIZE];
GetParity(cmd, len, parity);
@ -904,7 +913,7 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
//-----------------------------------------------------------------------------
// Read a SRI512 ISO 14443 tag.
// Read a SRI512 ISO 14443B tag.
//
// SRI512 tags are just simple memory tags, here we're looking at making a dump
// of the contents of the memory. No anticollision algorithm is done, we assume
@ -912,7 +921,7 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
//
// I tried to be systematic and check every answer of the tag, every CRC, etc...
//-----------------------------------------------------------------------------
void ReadSTMemoryIso14443(uint32_t dwLast)
void ReadSTMemoryIso14443b(uint32_t dwLast)
{
clear_trace();
set_tracing(TRUE);
@ -933,15 +942,15 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
// Signal field is on with the appropriate LED
LED_D_ON();
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
SpinDelay(200);
// First command: wake up the tag using the INITIATE command
uint8_t cmd1[] = { 0x06, 0x00, 0x97, 0x5b};
uint8_t cmd1[] = {0x06, 0x00, 0x97, 0x5b};
CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
// LED_A_OFF();
if (Demod.len == 0) {
@ -949,7 +958,7 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
return;
} else {
Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %x %x %x",
Demod.output[0], Demod.output[1],Demod.output[2]);
Demod.output[0], Demod.output[1], Demod.output[2]);
}
// There is a response, SELECT the uid
DbpString("Now SELECT tag:");
@ -959,22 +968,22 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
// LED_A_OFF();
if (Demod.len != 3) {
Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
return;
Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
return;
}
// Check the CRC of the answer:
ComputeCrc14443(CRC_14443_B, Demod.output, 1 , &cmd1[2], &cmd1[3]);
if(cmd1[2] != Demod.output[1] || cmd1[3] != Demod.output[2]) {
DbpString("CRC Error reading select response.");
return;
DbpString("CRC Error reading select response.");
return;
}
// Check response from the tag: should be the same UID as the command we just sent:
if (cmd1[1] != Demod.output[0]) {
Dbprintf("Bad response to SELECT from Tag, aborting: %x %x", cmd1[1], Demod.output[0]);
return;
Dbprintf("Bad response to SELECT from Tag, aborting: %x %x", cmd1[1], Demod.output[0]);
return;
}
// Tag is now selected,
// First get the tag's UID:
@ -983,22 +992,22 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
CodeAndTransmit14443bAsReader(cmd1, 3); // Only first three bytes for this one
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
// LED_A_OFF();
if (Demod.len != 10) {
Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
return;
Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
return;
}
// The check the CRC of the answer (use cmd1 as temporary variable):
ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
(cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
// Do not return;, let's go on... (we should retry, maybe ?)
if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
(cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
// Do not return;, let's go on... (we should retry, maybe ?)
}
Dbprintf("Tag UID (64 bits): %08x %08x",
(Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
(Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
// Now loop to read all 16 blocks, address from 0 to last block
Dbprintf("Tag memory dump, block 0 to %d",dwLast);
@ -1006,7 +1015,7 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
i = 0x00;
dwLast++;
for (;;) {
if (i == dwLast) {
if (i == dwLast) {
DbpString("System area block (0xff):");
i = 0xff;
}
@ -1015,25 +1024,25 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
// LED_A_ON();
GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
// LED_A_OFF();
if (Demod.len != 6) { // Check if we got an answer from the tag
DbpString("Expected 6 bytes from tag, got less...");
return;
DbpString("Expected 6 bytes from tag, got less...");
return;
}
// The check the CRC of the answer (use cmd1 as temporary variable):
ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
(cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
// Do not return;, let's go on... (we should retry, maybe ?)
if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
(cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
// Do not return;, let's go on... (we should retry, maybe ?)
}
// Now print out the memory location:
Dbprintf("Address=%x, Contents=%x, CRC=%x", i,
(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
(Demod.output[4]<<8)+Demod.output[5]);
(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
(Demod.output[4]<<8)+Demod.output[5]);
if (i == 0xff) {
break;
break;
}
i++;
}
@ -1054,10 +1063,10 @@ void ReadSTMemoryIso14443(uint32_t dwLast)
* Memory usage for this function, (within BigBuf)
* Last Received command (reader->tag) - MAX_FRAME_SIZE
* Last Received command (tag->reader) - MAX_FRAME_SIZE
* DMA Buffer, 1024 bytes (samples) - DMA_BUFFER_SIZE
* DMA Buffer - ISO14443B_DMA_BUFFER_SIZE
* Demodulated samples received - all the rest
*/
void RAMFUNC SnoopIso14443(void)
void RAMFUNC SnoopIso14443b(void)
{
// We won't start recording the frames that we acquire until we trigger;
// a good trigger condition to get started is probably when we see a
@ -1071,7 +1080,7 @@ void RAMFUNC SnoopIso14443(void)
set_tracing(TRUE);
// The DMA buffer, used to stream samples from the FPGA
int8_t *dmaBuf = (int8_t*) BigBuf_malloc(DMA_BUFFER_SIZE);
int8_t *dmaBuf = (int8_t*) BigBuf_malloc(ISO14443B_DMA_BUFFER_SIZE);
int lastRxCounter;
int8_t *upTo;
int ci, cq;
@ -1089,24 +1098,21 @@ void RAMFUNC SnoopIso14443(void)
Dbprintf(" Trace: %i bytes", BigBuf_max_traceLen());
Dbprintf(" Reader -> tag: %i bytes", MAX_FRAME_SIZE);
Dbprintf(" tag -> Reader: %i bytes", MAX_FRAME_SIZE);
Dbprintf(" DMA: %i bytes", DMA_BUFFER_SIZE);
Dbprintf(" DMA: %i bytes", ISO14443B_DMA_BUFFER_SIZE);
// Signal field is off with the appropriate LED
LED_D_OFF();
// Signal field is off, no reader signal, no tag signal
LEDsoff();
// And put the FPGA in the appropriate mode
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ |
FPGA_HF_READER_RX_XCORR_SNOOP);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_SNOOP);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// Setup for the DMA.
FpgaSetupSsc();
upTo = dmaBuf;
lastRxCounter = DMA_BUFFER_SIZE;
FpgaSetupSscDma((uint8_t*) dmaBuf, DMA_BUFFER_SIZE);
lastRxCounter = ISO14443B_DMA_BUFFER_SIZE;
FpgaSetupSscDma((uint8_t*) dmaBuf, ISO14443B_DMA_BUFFER_SIZE);
uint8_t parity[MAX_PARITY_SIZE];
LED_A_ON();
bool TagIsActive = FALSE;
bool ReaderIsActive = FALSE;
@ -1114,50 +1120,56 @@ void RAMFUNC SnoopIso14443(void)
// And now we loop, receiving samples.
for(;;) {
int behindBy = (lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR) &
(DMA_BUFFER_SIZE-1);
(ISO14443B_DMA_BUFFER_SIZE-1);
if(behindBy > maxBehindBy) {
maxBehindBy = behindBy;
if(behindBy > (9*DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
break;
}
}
if(behindBy < 2) continue;
ci = upTo[0];
cq = upTo[1];
upTo += 2;
lastRxCounter -= 2;
if(upTo >= dmaBuf + DMA_BUFFER_SIZE) {
if(upTo >= dmaBuf + ISO14443B_DMA_BUFFER_SIZE) {
upTo = dmaBuf;
lastRxCounter += DMA_BUFFER_SIZE;
lastRxCounter += ISO14443B_DMA_BUFFER_SIZE;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;
AT91C_BASE_PDC_SSC->PDC_RNCR = DMA_BUFFER_SIZE;
AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
WDT_HIT();
if(behindBy > (9*ISO14443B_DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
break;
}
if(!tracing) {
DbpString("Reached trace limit");
break;
}
if(BUTTON_PRESS()) {
DbpString("cancelled");
break;
}
}
samples += 2;
if (!TagIsActive) { // no need to try decoding reader data if the tag is sending
if(Handle14443UartBit(ci & 0x01)) {
if(Handle14443bUartBit(ci & 0x01)) {
if(triggered && tracing) {
GetParity(Uart.output, Uart.byteCnt, parity);
LogTrace(Uart.output,Uart.byteCnt,samples, samples,parity,TRUE);
LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);
}
if(Uart.byteCnt==0) Dbprintf("[1] Error, Uart.byteCnt==0, Uart.bitCnt=%d", Uart.bitCnt);
/* And ready to receive another command. */
UartReset();
/* And also reset the demod code, which might have been */
/* false-triggered by the commands from the reader. */
DemodReset();
}
if(Handle14443UartBit(cq & 0x01)) {
if(Handle14443bUartBit(cq & 0x01)) {
if(triggered && tracing) {
GetParity(Uart.output, Uart.byteCnt, parity);
LogTrace(Uart.output,Uart.byteCnt,samples, samples, parity, TRUE);
LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);
}
if(Uart.byteCnt==0) Dbprintf("[2] Error, Uart.byteCnt==0, Uart.bitCnt=%d", Uart.bitCnt);
/* And ready to receive another command. */
UartReset();
/* And also reset the demod code, which might have been */
@ -1168,7 +1180,7 @@ void RAMFUNC SnoopIso14443(void)
}
if(!ReaderIsActive) { // no need to try decoding tag data if the reader is sending - and we cannot afford the time
if(Handle14443SamplesDemod(ci & 0xFE, cq & 0xFE)) {
if(Handle14443bSamplesDemod(ci & 0xFE, cq & 0xFE)) {
//Use samples as a time measurement
if(tracing)
@ -1178,31 +1190,17 @@ void RAMFUNC SnoopIso14443(void)
LogTrace(Demod.output, Demod.len, samples, samples, parity, FALSE);
}
triggered = TRUE;
LED_A_OFF();
LED_B_ON();
// And ready to receive another response.
DemodReset();
}
TagIsActive = (Demod.state != DEMOD_UNSYNCD);
TagIsActive = (Demod.state > DEMOD_PHASE_REF_TRAINING);
}
WDT_HIT();
if(!tracing) {
DbpString("Reached trace limit");
break;
}
if(BUTTON_PRESS()) {
DbpString("cancelled");
break;
}
}
FpgaDisableSscDma();
LED_A_OFF();
LED_B_OFF();
LED_C_OFF();
LEDsoff();
AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
DbpString("Snoop statistics:");
Dbprintf(" Max behind by: %i", maxBehindBy);
@ -1228,38 +1226,36 @@ void RAMFUNC SnoopIso14443(void)
void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield, uint8_t data[])
{
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
if(!powerfield)
{
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
FpgaSetupSsc();
set_tracing(TRUE);
/* if(!powerfield) {
// Make sure that we start from off, since the tags are stateful;
// confusing things will happen if we don't reset them between reads.
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LED_D_OFF();
SpinDelay(200);
}
*/
if(!GETBIT(GPIO_LED_D))
{
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
FpgaSetupSsc();
// Now give it time to spin up.
// Signal field is on with the appropriate LED
LED_D_ON();
FpgaWriteConfWord(
FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
SpinDelay(200);
}
// if(!GETBIT(GPIO_LED_D)) { // if field is off
// FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
// // Signal field is on with the appropriate LED
// LED_D_ON();
// SpinDelay(200);
// }
CodeAndTransmit14443bAsReader(data, datalen);
if(recv)
{
GetSamplesFor14443Demod(TRUE, RECEIVE_SAMPLES_TIMEOUT, TRUE);
uint16_t iLen = MIN(Demod.len,USB_CMD_DATA_SIZE);
cmd_send(CMD_ACK,iLen,0,0,Demod.output,iLen);
if(recv) {
GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
uint16_t iLen = MIN(Demod.len, USB_CMD_DATA_SIZE);
cmd_send(CMD_ACK, iLen, 0, 0, Demod.output, iLen);
}
if(!powerfield)
{
if(!powerfield) {
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LED_D_OFF();
}

View file

@ -288,7 +288,7 @@ int CmdHF14BCmdRaw (const char *cmd) {
if (WaitForResponseTimeout(CMD_ACK,&resp,1000)) {
recv = resp.d.asBytes;
PrintAndLog("received %i octets",resp.arg[0]);
if(!resp.arg[0])
if(resp.arg[0] == 0)
return 0;
hexout = (char *)malloc(resp.arg[0] * 3 + 1);
if (hexout != NULL) {
@ -298,11 +298,13 @@ int CmdHF14BCmdRaw (const char *cmd) {
}
PrintAndLog("%s", hexout);
free(hexout);
ComputeCrc14443(CRC_14443_B, recv, resp.arg[0]-2, &first, &second);
if(recv[resp.arg[0]-2]==first && recv[resp.arg[0]-1]==second) {
PrintAndLog("CRC OK");
} else {
PrintAndLog("CRC failed");
if (resp.arg[0] > 2) {
ComputeCrc14443(CRC_14443_B, recv, resp.arg[0]-2, &first, &second);
if(recv[resp.arg[0]-2]==first && recv[resp.arg[0]-1]==second) {
PrintAndLog("CRC OK");
} else {
PrintAndLog("CRC failed");
}
}
} else {
PrintAndLog("malloc failed your client has low memory?");

Binary file not shown.

View file

@ -67,15 +67,10 @@ assign major_mode = conf_word[7:5];
// some fraction of the buffers)
wire hi_read_tx_shallow_modulation = conf_word[0];
// For the high-frequency receive correlator: frequency against which to
// correlate.
wire hi_read_rx_xcorr_848 = conf_word[0];
// and whether to drive the coil (reader) or just short it (snooper)
// For the high-frequency receive correlator:
// whether to drive the coil (reader) or just short it (snooper)
wire hi_read_rx_xcorr_snoop = conf_word[1];
// Divide the expected subcarrier frequency for hi_read_rx_xcorr by 4
wire hi_read_rx_xcorr_quarter = conf_word[2];
// For the high-frequency simulated tag: what kind of modulation to use.
wire [2:0] hi_simulate_mod_type = conf_word[2:0];
@ -102,7 +97,7 @@ hi_read_rx_xcorr hrxc(
hrxc_ssp_frame, hrxc_ssp_din, ssp_dout, hrxc_ssp_clk,
cross_hi, cross_lo,
hrxc_dbg,
hi_read_rx_xcorr_848, hi_read_rx_xcorr_snoop, hi_read_rx_xcorr_quarter
hi_read_rx_xcorr_snoop
);
hi_simulate hs(

View file

@ -10,7 +10,7 @@ module hi_read_rx_xcorr(
ssp_frame, ssp_din, ssp_dout, ssp_clk,
cross_hi, cross_lo,
dbg,
xcorr_is_848, snoop, xcorr_quarter_freq
snoop
);
input pck0, ck_1356meg, ck_1356megb;
output pwr_lo, pwr_hi, pwr_oe1, pwr_oe2, pwr_oe3, pwr_oe4;
@ -20,58 +20,20 @@ module hi_read_rx_xcorr(
output ssp_frame, ssp_din, ssp_clk;
input cross_hi, cross_lo;
output dbg;
input xcorr_is_848, snoop, xcorr_quarter_freq;
input snoop;
// Carrier is steady on through this, unless we're snooping.
assign pwr_hi = ck_1356megb & (~snoop);
assign pwr_oe1 = 1'b0;
assign pwr_oe2 = 1'b0;
assign pwr_oe3 = 1'b0;
assign pwr_oe4 = 1'b0;
reg ssp_clk;
reg ssp_frame;
reg fc_div_2;
always @(posedge ck_1356meg)
fc_div_2 = ~fc_div_2;
reg fc_div_4;
always @(posedge fc_div_2)
fc_div_4 = ~fc_div_4;
reg fc_div_8;
always @(posedge fc_div_4)
fc_div_8 = ~fc_div_8;
reg adc_clk;
always @(xcorr_is_848 or xcorr_quarter_freq or ck_1356meg)
if(~xcorr_quarter_freq)
begin
if(xcorr_is_848)
// The subcarrier frequency is fc/16; we will sample at fc, so that
// means the subcarrier is 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 1 1 ...
adc_clk <= ck_1356meg;
else
// The subcarrier frequency is fc/32; we will sample at fc/2, and
// the subcarrier will look identical.
adc_clk <= fc_div_2;
end
else
begin
if(xcorr_is_848)
// The subcarrier frequency is fc/64
adc_clk <= fc_div_4;
else
// The subcarrier frequency is fc/128
adc_clk <= fc_div_8;
end
wire adc_clk = ck_1356megb;
// When we're a reader, we just need to do the BPSK demod; but when we're an
// eavesdropper, we also need to pick out the commands sent by the reader,
// using AM. Do this the same way that we do it for the simulated tag.
reg after_hysteresis, after_hysteresis_prev;
reg after_hysteresis, after_hysteresis_prev, after_hysteresis_prev_prev;
reg [11:0] has_been_low_for;
always @(negedge adc_clk)
begin
@ -97,7 +59,6 @@ end
// Let us report a correlation every 4 subcarrier cycles, or 4*16 samples,
// so we need a 6-bit counter.
reg [5:0] corr_i_cnt;
reg [5:0] corr_q_cnt;
// And a couple of registers in which to accumulate the correlations.
// we would add at most 32 times adc_d, the result can be held in 13 bits.
// Need one additional bit because it can be negative as well
@ -105,32 +66,38 @@ reg signed [13:0] corr_i_accum;
reg signed [13:0] corr_q_accum;
reg signed [7:0] corr_i_out;
reg signed [7:0] corr_q_out;
// clock and frame signal for communication to ARM
reg ssp_clk;
reg ssp_frame;
// ADC data appears on the rising edge, so sample it on the falling edge
always @(negedge adc_clk)
begin
corr_i_cnt <= corr_i_cnt + 1;
// These are the correlators: we correlate against in-phase and quadrature
// versions of our reference signal, and keep the (signed) result to
// send out later over the SSP.
if(corr_i_cnt == 7'd63)
if(corr_i_cnt == 7'd0)
begin
if(snoop)
begin
// highest 7 significant bits of tag signal (signed), 1 bit reader signal:
corr_i_out <= {corr_i_accum[13:7], after_hysteresis_prev};
corr_q_out <= {corr_q_accum[13:7], after_hysteresis};
// 7 most significant bits of tag signal (signed), 1 bit reader signal:
corr_i_out <= {corr_i_accum[13:7], after_hysteresis_prev_prev};
corr_q_out <= {corr_q_accum[13:7], after_hysteresis_prev};
after_hysteresis_prev_prev <= after_hysteresis;
end
else
begin
// highest 8 significant bits of tag signal
// 8 most significant bits of tag signal
corr_i_out <= corr_i_accum[13:6];
corr_q_out <= corr_q_accum[13:6];
end
corr_i_accum <= adc_d;
corr_q_accum <= adc_d;
corr_q_cnt <= 4;
corr_i_cnt <= 0;
end
else
begin
@ -139,13 +106,11 @@ begin
else
corr_i_accum <= corr_i_accum + adc_d;
if(corr_q_cnt[3])
corr_q_accum <= corr_q_accum - adc_d;
else
if(corr_i_cnt[3] == corr_i_cnt[2]) // phase shifted by pi/2
corr_q_accum <= corr_q_accum + adc_d;
else
corr_q_accum <= corr_q_accum - adc_d;
corr_i_cnt <= corr_i_cnt + 1;
corr_q_cnt <= corr_q_cnt + 1;
end
// The logic in hi_simulate.v reports 4 samples per bit. We report two
@ -172,7 +137,7 @@ begin
end
// set ssp_frame signal for corr_i_cnt = 0..3 and corr_i_cnt = 32..35
// (two frames with 8 Bits each)
// (send two frames with 8 Bits each)
if(corr_i_cnt[5:2] == 4'b0000 || corr_i_cnt[5:2] == 4'b1000)
ssp_frame = 1'b1;
else
@ -186,5 +151,6 @@ assign dbg = corr_i_cnt[3];
// Unused.
assign pwr_lo = 1'b0;
assign pwr_oe2 = 1'b0;
endmodule