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proxmark3/armsrc/lfops.c
cex123@gmail.com ec09b62d88
2011-10-15 15:15:49 +00:00

1084 lines
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//-----------------------------------------------------------------------------
// 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.
//-----------------------------------------------------------------------------
// Miscellaneous routines for low frequency tag operations.
// Tags supported here so far are Texas Instruments (TI), HID
// Also routines for raw mode reading/simulating of LF waveform
//-----------------------------------------------------------------------------
#include "proxmark3.h"
#include "apps.h"
#include "util.h"
#include "hitag2.h"
#include "crc16.h"
#include "string.h"
void AcquireRawAdcSamples125k(int at134khz)
{
if (at134khz)
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
else
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
// Connect the A/D to the peak-detected low-frequency path.
SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
// Give it a bit of time for the resonant antenna to settle.
SpinDelay(50);
// Now set up the SSC to get the ADC samples that are now streaming at us.
FpgaSetupSsc();
// Now call the acquisition routine
DoAcquisition125k();
}
// split into two routines so we can avoid timing issues after sending commands //
void DoAcquisition125k(void)
{
uint8_t *dest = (uint8_t *)BigBuf;
int n = sizeof(BigBuf);
int i;
memset(dest, 0, n);
i = 0;
for(;;) {
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
AT91C_BASE_SSC->SSC_THR = 0x43;
LED_D_ON();
}
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
i++;
LED_D_OFF();
if (i >= n) break;
}
}
Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
}
void ModThenAcquireRawAdcSamples125k(int delay_off, int period_0, int period_1, uint8_t *command)
{
int at134khz;
/* Make sure the tag is reset */
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
SpinDelay(2500);
// see if 'h' was specified
if (command[strlen((char *) command) - 1] == 'h')
at134khz = TRUE;
else
at134khz = FALSE;
if (at134khz)
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
else
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
// Give it a bit of time for the resonant antenna to settle.
SpinDelay(50);
// And a little more time for the tag to fully power up
SpinDelay(2000);
// Now set up the SSC to get the ADC samples that are now streaming at us.
FpgaSetupSsc();
// now modulate the reader field
while(*command != '\0' && *command != ' ') {
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LED_D_OFF();
SpinDelayUs(delay_off);
if (at134khz)
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
else
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
LED_D_ON();
if(*(command++) == '0')
SpinDelayUs(period_0);
else
SpinDelayUs(period_1);
}
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
LED_D_OFF();
SpinDelayUs(delay_off);
if (at134khz)
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
else
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
// now do the read
DoAcquisition125k();
}
/* blank r/w tag data stream
...0000000000000000 01111111
1010101010101010101010101010101010101010101010101010101010101010
0011010010100001
01111111
101010101010101[0]000...
[5555fe852c5555555555555555fe0000]
*/
void ReadTItag(void)
{
// some hardcoded initial params
// when we read a TI tag we sample the zerocross line at 2Mhz
// TI tags modulate a 1 as 16 cycles of 123.2Khz
// TI tags modulate a 0 as 16 cycles of 134.2Khz
#define FSAMPLE 2000000
#define FREQLO 123200
#define FREQHI 134200
signed char *dest = (signed char *)BigBuf;
int n = sizeof(BigBuf);
// int *dest = GraphBuffer;
// int n = GraphTraceLen;
// 128 bit shift register [shift3:shift2:shift1:shift0]
uint32_t shift3 = 0, shift2 = 0, shift1 = 0, shift0 = 0;
int i, cycles=0, samples=0;
// how many sample points fit in 16 cycles of each frequency
uint32_t sampleslo = (FSAMPLE<<4)/FREQLO, sampleshi = (FSAMPLE<<4)/FREQHI;
// when to tell if we're close enough to one freq or another
uint32_t threshold = (sampleslo - sampleshi + 1)>>1;
// TI tags charge at 134.2Khz
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
// Place FPGA in passthrough mode, in this mode the CROSS_LO line
// connects to SSP_DIN and the SSP_DOUT logic level controls
// whether we're modulating the antenna (high)
// or listening to the antenna (low)
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
// get TI tag data into the buffer
AcquireTiType();
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
for (i=0; i<n-1; i++) {
// count cycles by looking for lo to hi zero crossings
if ( (dest[i]<0) && (dest[i+1]>0) ) {
cycles++;
// after 16 cycles, measure the frequency
if (cycles>15) {
cycles=0;
samples=i-samples; // number of samples in these 16 cycles
// TI bits are coming to us lsb first so shift them
// right through our 128 bit right shift register
shift0 = (shift0>>1) | (shift1 << 31);
shift1 = (shift1>>1) | (shift2 << 31);
shift2 = (shift2>>1) | (shift3 << 31);
shift3 >>= 1;
// check if the cycles fall close to the number
// expected for either the low or high frequency
if ( (samples>(sampleslo-threshold)) && (samples<(sampleslo+threshold)) ) {
// low frequency represents a 1
shift3 |= (1<<31);
} else if ( (samples>(sampleshi-threshold)) && (samples<(sampleshi+threshold)) ) {
// high frequency represents a 0
} else {
// probably detected a gay waveform or noise
// use this as gaydar or discard shift register and start again
shift3 = shift2 = shift1 = shift0 = 0;
}
samples = i;
// for each bit we receive, test if we've detected a valid tag
// if we see 17 zeroes followed by 6 ones, we might have a tag
// remember the bits are backwards
if ( ((shift0 & 0x7fffff) == 0x7e0000) ) {
// if start and end bytes match, we have a tag so break out of the loop
if ( ((shift0>>16)&0xff) == ((shift3>>8)&0xff) ) {
cycles = 0xF0B; //use this as a flag (ugly but whatever)
break;
}
}
}
}
}
// if flag is set we have a tag
if (cycles!=0xF0B) {
DbpString("Info: No valid tag detected.");
} else {
// put 64 bit data into shift1 and shift0
shift0 = (shift0>>24) | (shift1 << 8);
shift1 = (shift1>>24) | (shift2 << 8);
// align 16 bit crc into lower half of shift2
shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;
// if r/w tag, check ident match
if ( shift3&(1<<15) ) {
DbpString("Info: TI tag is rewriteable");
// only 15 bits compare, last bit of ident is not valid
if ( ((shift3>>16)^shift0)&0x7fff ) {
DbpString("Error: Ident mismatch!");
} else {
DbpString("Info: TI tag ident is valid");
}
} else {
DbpString("Info: TI tag is readonly");
}
// WARNING the order of the bytes in which we calc crc below needs checking
// i'm 99% sure the crc algorithm is correct, but it may need to eat the
// bytes in reverse or something
// calculate CRC
uint32_t crc=0;
crc = update_crc16(crc, (shift0)&0xff);
crc = update_crc16(crc, (shift0>>8)&0xff);
crc = update_crc16(crc, (shift0>>16)&0xff);
crc = update_crc16(crc, (shift0>>24)&0xff);
crc = update_crc16(crc, (shift1)&0xff);
crc = update_crc16(crc, (shift1>>8)&0xff);
crc = update_crc16(crc, (shift1>>16)&0xff);
crc = update_crc16(crc, (shift1>>24)&0xff);
Dbprintf("Info: Tag data: %x%08x, crc=%x",
(unsigned int)shift1, (unsigned int)shift0, (unsigned int)shift2 & 0xFFFF);
if (crc != (shift2&0xffff)) {
Dbprintf("Error: CRC mismatch, expected %x", (unsigned int)crc);
} else {
DbpString("Info: CRC is good");
}
}
}
void WriteTIbyte(uint8_t b)
{
int i = 0;
// modulate 8 bits out to the antenna
for (i=0; i<8; i++)
{
if (b&(1<<i)) {
// stop modulating antenna
LOW(GPIO_SSC_DOUT);
SpinDelayUs(1000);
// modulate antenna
HIGH(GPIO_SSC_DOUT);
SpinDelayUs(1000);
} else {
// stop modulating antenna
LOW(GPIO_SSC_DOUT);
SpinDelayUs(300);
// modulate antenna
HIGH(GPIO_SSC_DOUT);
SpinDelayUs(1700);
}
}
}
void AcquireTiType(void)
{
int i, j, n;
// tag transmission is <20ms, sampling at 2M gives us 40K samples max
// each sample is 1 bit stuffed into a uint32_t so we need 1250 uint32_t
#define TIBUFLEN 1250
// clear buffer
memset(BigBuf,0,sizeof(BigBuf));
// Set up the synchronous serial port
AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN;
// steal this pin from the SSP and use it to control the modulation
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
AT91C_BASE_SSC->SSC_CR = AT91C_SSC_SWRST;
AT91C_BASE_SSC->SSC_CR = AT91C_SSC_RXEN | AT91C_SSC_TXEN;
// Sample at 2 Mbit/s, so TI tags are 16.2 vs. 14.9 clocks long
// 48/2 = 24 MHz clock must be divided by 12
AT91C_BASE_SSC->SSC_CMR = 12;
AT91C_BASE_SSC->SSC_RCMR = SSC_CLOCK_MODE_SELECT(0);
AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(32) | AT91C_SSC_MSBF;
AT91C_BASE_SSC->SSC_TCMR = 0;
AT91C_BASE_SSC->SSC_TFMR = 0;
LED_D_ON();
// modulate antenna
HIGH(GPIO_SSC_DOUT);
// Charge TI tag for 50ms.
SpinDelay(50);
// stop modulating antenna and listen
LOW(GPIO_SSC_DOUT);
LED_D_OFF();
i = 0;
for(;;) {
if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
BigBuf[i] = AT91C_BASE_SSC->SSC_RHR; // store 32 bit values in buffer
i++; if(i >= TIBUFLEN) break;
}
WDT_HIT();
}
// return stolen pin to SSP
AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN | GPIO_SSC_DOUT;
char *dest = (char *)BigBuf;
n = TIBUFLEN*32;
// unpack buffer
for (i=TIBUFLEN-1; i>=0; i--) {
for (j=0; j<32; j++) {
if(BigBuf[i] & (1 << j)) {
dest[--n] = 1;
} else {
dest[--n] = -1;
}
}
}
}
// arguments: 64bit data split into 32bit idhi:idlo and optional 16bit crc
// if crc provided, it will be written with the data verbatim (even if bogus)
// if not provided a valid crc will be computed from the data and written.
void WriteTItag(uint32_t idhi, uint32_t idlo, uint16_t crc)
{
if(crc == 0) {
crc = update_crc16(crc, (idlo)&0xff);
crc = update_crc16(crc, (idlo>>8)&0xff);
crc = update_crc16(crc, (idlo>>16)&0xff);
crc = update_crc16(crc, (idlo>>24)&0xff);
crc = update_crc16(crc, (idhi)&0xff);
crc = update_crc16(crc, (idhi>>8)&0xff);
crc = update_crc16(crc, (idhi>>16)&0xff);
crc = update_crc16(crc, (idhi>>24)&0xff);
}
Dbprintf("Writing to tag: %x%08x, crc=%x",
(unsigned int) idhi, (unsigned int) idlo, crc);
// TI tags charge at 134.2Khz
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
// Place FPGA in passthrough mode, in this mode the CROSS_LO line
// connects to SSP_DIN and the SSP_DOUT logic level controls
// whether we're modulating the antenna (high)
// or listening to the antenna (low)
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
LED_A_ON();
// steal this pin from the SSP and use it to control the modulation
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
// writing algorithm:
// a high bit consists of a field off for 1ms and field on for 1ms
// a low bit consists of a field off for 0.3ms and field on for 1.7ms
// initiate a charge time of 50ms (field on) then immediately start writing bits
// start by writing 0xBB (keyword) and 0xEB (password)
// then write 80 bits of data (or 64 bit data + 16 bit crc if you prefer)
// finally end with 0x0300 (write frame)
// all data is sent lsb firts
// finish with 15ms programming time
// modulate antenna
HIGH(GPIO_SSC_DOUT);
SpinDelay(50); // charge time
WriteTIbyte(0xbb); // keyword
WriteTIbyte(0xeb); // password
WriteTIbyte( (idlo )&0xff );
WriteTIbyte( (idlo>>8 )&0xff );
WriteTIbyte( (idlo>>16)&0xff );
WriteTIbyte( (idlo>>24)&0xff );
WriteTIbyte( (idhi )&0xff );
WriteTIbyte( (idhi>>8 )&0xff );
WriteTIbyte( (idhi>>16)&0xff );
WriteTIbyte( (idhi>>24)&0xff ); // data hi to lo
WriteTIbyte( (crc )&0xff ); // crc lo
WriteTIbyte( (crc>>8 )&0xff ); // crc hi
WriteTIbyte(0x00); // write frame lo
WriteTIbyte(0x03); // write frame hi
HIGH(GPIO_SSC_DOUT);
SpinDelay(50); // programming time
LED_A_OFF();
// get TI tag data into the buffer
AcquireTiType();
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
DbpString("Now use tiread to check");
}
void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
{
int i;
uint8_t *tab = (uint8_t *)BigBuf;
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT | GPIO_SSC_CLK;
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_CLK;
#define SHORT_COIL() LOW(GPIO_SSC_DOUT)
#define OPEN_COIL() HIGH(GPIO_SSC_DOUT)
i = 0;
for(;;) {
while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)) {
if(BUTTON_PRESS()) {
DbpString("Stopped");
return;
}
WDT_HIT();
}
if (ledcontrol)
LED_D_ON();
if(tab[i])
OPEN_COIL();
else
SHORT_COIL();
if (ledcontrol)
LED_D_OFF();
while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK) {
if(BUTTON_PRESS()) {
DbpString("Stopped");
return;
}
WDT_HIT();
}
i++;
if(i == period) {
i = 0;
if (gap) {
SHORT_COIL();
SpinDelayUs(gap);
}
}
}
}
/* Provides a framework for bidirectional LF tag communication
* Encoding is currently Hitag2, but the general idea can probably
* be transferred to other encodings.
*
* The new FPGA code will, for the LF simulator mode, give on SSC_FRAME
* (PA15) a thresholded version of the signal from the ADC. Setting the
* ADC path to the low frequency peak detection signal, will enable a
* somewhat reasonable receiver for modulation on the carrier signal
* that is generated by the reader. The signal is low when the reader
* field is switched off, and high when the reader field is active. Due
* to the way that the signal looks like, mostly only the rising edge is
* useful, your mileage may vary.
*
* Neat perk: PA15 can not only be used as a bit-banging GPIO, but is also
* TIOA1, which can be used as the capture input for timer 1. This should
* make it possible to measure the exact edge-to-edge time, without processor
* intervention.
*
* Arguments: divisor is the divisor to be sent to the FPGA (e.g. 95 for 125kHz)
* t0 is the carrier frequency cycle duration in terms of MCK (384 for 125kHz)
*
* The following defines are in carrier periods:
*/
#define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */
#define HITAG_T_1_MIN 24 /* T[1] should be 26..30 */
#define HITAG_T_EOF 40 /* T_EOF should be > 36 */
#define HITAG_T_WRESP 208 /* T_wresp should be 204..212 */
static void hitag_handle_frame(int t0, int frame_len, char *frame);
//#define DEBUG_RA_VALUES 1
#define DEBUG_FRAME_CONTENTS 1
void SimulateTagLowFrequencyBidir(int divisor, int t0)
{
#if DEBUG_RA_VALUES || DEBUG_FRAME_CONTENTS
int i = 0;
#endif
char frame[10];
int frame_pos=0;
DbpString("Starting Hitag2 emulator, press button to end");
hitag2_init();
/* Set up simulator mode, frequency divisor which will drive the FPGA
* and analog mux selection.
*/
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
RELAY_OFF();
/* Set up Timer 1:
* Capture mode, timer source MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
* external trigger rising edge, load RA on rising edge of TIOA, load RB on rising
* edge of TIOA. Assign PA15 to TIOA1 (peripheral B)
*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK |
AT91C_TC_ETRGEDG_RISING |
AT91C_TC_ABETRG |
AT91C_TC_LDRA_RISING |
AT91C_TC_LDRB_RISING;
AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN |
AT91C_TC_SWTRG;
/* calculate the new value for the carrier period in terms of TC1 values */
t0 = t0/2;
int overflow = 0;
while(!BUTTON_PRESS()) {
WDT_HIT();
if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
int ra = AT91C_BASE_TC1->TC_RA;
if((ra > t0*HITAG_T_EOF) | overflow) ra = t0*HITAG_T_EOF+1;
#if DEBUG_RA_VALUES
if(ra > 255 || overflow) ra = 255;
((char*)BigBuf)[i] = ra;
i = (i+1) % 8000;
#endif
if(overflow || (ra > t0*HITAG_T_EOF) || (ra < t0*HITAG_T_0_MIN)) {
/* Ignore */
} else if(ra >= t0*HITAG_T_1_MIN ) {
/* '1' bit */
if(frame_pos < 8*sizeof(frame)) {
frame[frame_pos / 8] |= 1<<( 7-(frame_pos%8) );
frame_pos++;
}
} else if(ra >= t0*HITAG_T_0_MIN) {
/* '0' bit */
if(frame_pos < 8*sizeof(frame)) {
frame[frame_pos / 8] |= 0<<( 7-(frame_pos%8) );
frame_pos++;
}
}
overflow = 0;
LED_D_ON();
} else {
if(AT91C_BASE_TC1->TC_CV > t0*HITAG_T_EOF) {
/* Minor nuisance: In Capture mode, the timer can not be
* stopped by a Compare C. There's no way to stop the clock
* in software, so we'll just have to note the fact that an
* overflow happened and the next loaded timer value might
* have wrapped. Also, this marks the end of frame, and the
* still running counter can be used to determine the correct
* time for the start of the reply.
*/
overflow = 1;
if(frame_pos > 0) {
/* Have a frame, do something with it */
#if DEBUG_FRAME_CONTENTS
((char*)BigBuf)[i++] = frame_pos;
memcpy( ((char*)BigBuf)+i, frame, 7);
i+=7;
i = i % sizeof(BigBuf);
#endif
hitag_handle_frame(t0, frame_pos, frame);
memset(frame, 0, sizeof(frame));
}
frame_pos = 0;
}
LED_D_OFF();
}
}
DbpString("All done");
}
static void hitag_send_bit(int t0, int bit) {
if(bit == 1) {
/* Manchester: Loaded, then unloaded */
LED_A_ON();
SHORT_COIL();
while(AT91C_BASE_TC1->TC_CV < t0*15);
OPEN_COIL();
while(AT91C_BASE_TC1->TC_CV < t0*31);
LED_A_OFF();
} else if(bit == 0) {
/* Manchester: Unloaded, then loaded */
LED_B_ON();
OPEN_COIL();
while(AT91C_BASE_TC1->TC_CV < t0*15);
SHORT_COIL();
while(AT91C_BASE_TC1->TC_CV < t0*31);
LED_B_OFF();
}
AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; /* Reset clock for the next bit */
}
static void hitag_send_frame(int t0, int frame_len, const char const * frame, int fdt)
{
OPEN_COIL();
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
/* Wait for HITAG_T_WRESP carrier periods after the last reader bit,
* not that since the clock counts since the rising edge, but T_wresp is
* with respect to the falling edge, we need to wait actually (T_wresp - T_g)
* periods. The gap time T_g varies (4..10).
*/
while(AT91C_BASE_TC1->TC_CV < t0*(fdt-8));
int saved_cmr = AT91C_BASE_TC1->TC_CMR;
AT91C_BASE_TC1->TC_CMR &= ~AT91C_TC_ETRGEDG; /* Disable external trigger for the clock */
AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; /* Reset the clock and use it for response timing */
int i;
for(i=0; i<5; i++)
hitag_send_bit(t0, 1); /* Start of frame */
for(i=0; i<frame_len; i++) {
hitag_send_bit(t0, !!(frame[i/ 8] & (1<<( 7-(i%8) ))) );
}
OPEN_COIL();
AT91C_BASE_TC1->TC_CMR = saved_cmr;
}
/* Callback structure to cleanly separate tag emulation code from the radio layer. */
static int hitag_cb(const char* response_data, const int response_length, const int fdt, void *cb_cookie)
{
hitag_send_frame(*(int*)cb_cookie, response_length, response_data, fdt);
return 0;
}
/* Frame length in bits, frame contents in MSBit first format */
static void hitag_handle_frame(int t0, int frame_len, char *frame)
{
hitag2_handle_command(frame, frame_len, hitag_cb, &t0);
}
// compose fc/8 fc/10 waveform
static void fc(int c, int *n) {
uint8_t *dest = (uint8_t *)BigBuf;
int idx;
// for when we want an fc8 pattern every 4 logical bits
if(c==0) {
dest[((*n)++)]=1;
dest[((*n)++)]=1;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
}
// an fc/8 encoded bit is a bit pattern of 11000000 x6 = 48 samples
if(c==8) {
for (idx=0; idx<6; idx++) {
dest[((*n)++)]=1;
dest[((*n)++)]=1;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
}
}
// an fc/10 encoded bit is a bit pattern of 1110000000 x5 = 50 samples
if(c==10) {
for (idx=0; idx<5; idx++) {
dest[((*n)++)]=1;
dest[((*n)++)]=1;
dest[((*n)++)]=1;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
dest[((*n)++)]=0;
}
}
}
// prepare a waveform pattern in the buffer based on the ID given then
// simulate a HID tag until the button is pressed
void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
{
int n=0, i=0;
/*
HID tag bitstream format
The tag contains a 44bit unique code. This is sent out MSB first in sets of 4 bits
A 1 bit is represented as 6 fc8 and 5 fc10 patterns
A 0 bit is represented as 5 fc10 and 6 fc8 patterns
A fc8 is inserted before every 4 bits
A special start of frame pattern is used consisting a0b0 where a and b are neither 0
nor 1 bits, they are special patterns (a = set of 12 fc8 and b = set of 10 fc10)
*/
if (hi>0xFFF) {
DbpString("Tags can only have 44 bits.");
return;
}
fc(0,&n);
// special start of frame marker containing invalid bit sequences
fc(8, &n); fc(8, &n); // invalid
fc(8, &n); fc(10, &n); // logical 0
fc(10, &n); fc(10, &n); // invalid
fc(8, &n); fc(10, &n); // logical 0
WDT_HIT();
// manchester encode bits 43 to 32
for (i=11; i>=0; i--) {
if ((i%4)==3) fc(0,&n);
if ((hi>>i)&1) {
fc(10, &n); fc(8, &n); // low-high transition
} else {
fc(8, &n); fc(10, &n); // high-low transition
}
}
WDT_HIT();
// manchester encode bits 31 to 0
for (i=31; i>=0; i--) {
if ((i%4)==3) fc(0,&n);
if ((lo>>i)&1) {
fc(10, &n); fc(8, &n); // low-high transition
} else {
fc(8, &n); fc(10, &n); // high-low transition
}
}
if (ledcontrol)
LED_A_ON();
SimulateTagLowFrequency(n, 0, ledcontrol);
if (ledcontrol)
LED_A_OFF();
}
// loop to capture raw HID waveform then FSK demodulate the TAG ID from it
void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
{
uint8_t *dest = (uint8_t *)BigBuf;
int m=0, n=0, i=0, idx=0, found=0, lastval=0;
uint32_t hi=0, lo=0;
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
// Connect the A/D to the peak-detected low-frequency path.
SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
// Give it a bit of time for the resonant antenna to settle.
SpinDelay(50);
// Now set up the SSC to get the ADC samples that are now streaming at us.
FpgaSetupSsc();
for(;;) {
WDT_HIT();
if (ledcontrol)
LED_A_ON();
if(BUTTON_PRESS()) {
DbpString("Stopped");
if (ledcontrol)
LED_A_OFF();
return;
}
i = 0;
m = sizeof(BigBuf);
memset(dest,128,m);
for(;;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0x43;
if (ledcontrol)
LED_D_ON();
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
// we don't care about actual value, only if it's more or less than a
// threshold essentially we capture zero crossings for later analysis
if(dest[i] < 127) dest[i] = 0; else dest[i] = 1;
i++;
if (ledcontrol)
LED_D_OFF();
if(i >= m) {
break;
}
}
}
// FSK demodulator
// sync to first lo-hi transition
for( idx=1; idx<m; idx++) {
if (dest[idx-1]<dest[idx])
lastval=idx;
break;
}
WDT_HIT();
// 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( i=0; idx<m; idx++) {
if (dest[idx-1]<dest[idx]) {
dest[i]=idx-lastval;
if (dest[i] <= 8) {
dest[i]=1;
} else {
dest[i]=0;
}
lastval=idx;
i++;
}
}
m=i;
WDT_HIT();
// we now have a set of cycle counts, loop over previous results and aggregate data into bit patterns
lastval=dest[0];
idx=0;
i=0;
n=0;
for( idx=0; idx<m; idx++) {
if (dest[idx]==lastval) {
n++;
} else {
// a bit time is five fc/10 or six fc/8 cycles so figure out how many bits a pattern width represents,
// an extra fc/8 pattern preceeds every 4 bits (about 200 cycles) just to complicate things but it gets
// swallowed up by rounding
// expected results are 1 or 2 bits, any more and it's an invalid manchester encoding
// special start of frame markers use invalid manchester states (no transitions) by using sequences
// like 111000
if (dest[idx-1]) {
n=(n+1)/6; // fc/8 in sets of 6
} else {
n=(n+1)/5; // fc/10 in sets of 5
}
switch (n) { // stuff appropriate bits in buffer
case 0:
case 1: // one bit
dest[i++]=dest[idx-1];
break;
case 2: // two bits
dest[i++]=dest[idx-1];
dest[i++]=dest[idx-1];
break;
case 3: // 3 bit start of frame markers
dest[i++]=dest[idx-1];
dest[i++]=dest[idx-1];
dest[i++]=dest[idx-1];
break;
// When a logic 0 is immediately followed by the start of the next transmisson
// (special pattern) a pattern of 4 bit duration lengths is created.
case 4:
dest[i++]=dest[idx-1];
dest[i++]=dest[idx-1];
dest[i++]=dest[idx-1];
dest[i++]=dest[idx-1];
break;
default: // this shouldn't happen, don't stuff any bits
break;
}
n=0;
lastval=dest[idx];
}
}
m=i;
WDT_HIT();
// 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
for( idx=0; idx<m-6; idx++) {
// search for a start of frame marker
if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
{
found=1;
idx+=6;
if (found && (hi|lo)) {
Dbprintf("TAG ID: %x%08x (%d)",
(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
/* if we're only looking for one tag */
if (findone)
{
*high = hi;
*low = lo;
return;
}
hi=0;
lo=0;
found=0;
}
}
if (found) {
if (dest[idx] && (!dest[idx+1]) ) {
hi=(hi<<1)|(lo>>31);
lo=(lo<<1)|0;
} else if ( (!dest[idx]) && dest[idx+1]) {
hi=(hi<<1)|(lo>>31);
lo=(lo<<1)|1;
} else {
found=0;
hi=0;
lo=0;
}
idx++;
}
if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
{
found=1;
idx+=6;
if (found && (hi|lo)) {
Dbprintf("TAG ID: %x%08x (%d)",
(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
/* if we're only looking for one tag */
if (findone)
{
*high = hi;
*low = lo;
return;
}
hi=0;
lo=0;
found=0;
}
}
}
WDT_HIT();
}
}
//----------------------
// T5557/T5567 routines
// Relevant times in microsecond
// To compensate antenna falling times shorten the write times
// and enlarge the gap ones.
#define start_gap 250
#define write_gap 160
#define write_0 144 //192
#define write_1 400 //432 for T55x7; 448 for E5550
//Write one bit to card
void T5567WriteBit(int bit)
{
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
if (bit == 0) SpinDelayUs(write_0);
else SpinDelayUs(write_1);
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
SpinDelayUs(write_gap);
}
//Write one card block in page 0, no lock
void T5567WriteBlock(int Data, int Block)
{
/* Make sure the tag is reset */
// FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
// SpinDelay(2500);
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
// Give it a bit of time for the resonant antenna to settle.
// And for the tag to fully power up
SpinDelay(150);
// now start writting
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
SpinDelayUs(start_gap);
//Opcode
T5567WriteBit(1);
T5567WriteBit(0); //Page 0
//Lock bit
T5567WriteBit(0);
//Data
for (int i=0;i<32;i++){
T5567WriteBit(Data&(1<<(31-i)));
}
//Page
for (int i=0;i<3;i++){
T5567WriteBit(Block&(1<<(2-i)));
}
//Now perform write (nominal is 5.6 ms for T55x7 and 18ms for E5550,
// so wait a little more)
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
SpinDelay(20);
}
//Copy HID id to card and setup block 0 config
void CopyHIDtoT5567(int hi, int lo)
{
int data1, data2, data3;
// ensure no more than 44 bits supplied
if (hi>0xFFF) {
DbpString("Tags can only have 44 bits.");
return;
}
//Build the 3 data blocks for supplied 44bit ID
data1 = 0x1D000000; //load preamble
for (int i=0;i<12;i++){
if (hi & (1<<(11-i))) data1 |= (1<<(((11-i)*2)+1)); // 1 -> 10
else data1 |= (1<<((11-i)*2)); // 0 -> 01
}
data2 = 0;
for (int i=0;i<16;i++){
if (lo & (1<<(31-i))) data2 |= (1<<(((15-i)*2)+1)); // 1 -> 10
else data2 |= (1<<((15-i)*2)); // 0 -> 01
}
data3 = 0;
for (int i=0;i<16;i++){
if (lo & (1<<(15-i))) data3 |= (1<<(((15-i)*2)+1)); // 1 -> 10
else data3 |= (1<<((15-i)*2)); // 0 -> 01
}
//Program the 3 data blocks for supplied 44bit ID
// and the block 0 for HID format
T5567WriteBlock(data1,1);
T5567WriteBlock(data2,2);
T5567WriteBlock(data3,3);
//Config for HID (RF/50;FSK2a;Maxblock=3)
T5567WriteBlock(0x00107060,0);
DbpString("DONE!");
}
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