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proxmark3/armsrc/legicrf.c

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//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
//
// 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.
//-----------------------------------------------------------------------------
// LEGIC RF simulation code
//-----------------------------------------------------------------------------
#include "proxmark3.h"
#include "apps.h"
#include "util.h"
#include "string.h"
#include "legicrf.h"
#include "legic_prng.h"
#include "crc.h"
static struct legic_frame {
int bits;
uint32_t data;
} current_frame;
static enum {
STATE_DISCON,
STATE_IV,
STATE_CON,
} legic_state;
static crc_t legic_crc;
static int legic_read_count;
static uint32_t legic_prng_bc;
static uint32_t legic_prng_iv;
static int legic_phase_drift;
static int legic_frame_drift;
static int legic_reqresp_drift;
AT91PS_TC timer;
AT91PS_TC prng_timer;
static void setup_timer(void)
{
/* Set up Timer 1 to use for measuring time between pulses. Since we're bit-banging
* this it won't be terribly accurate but should be good enough.
*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
timer = AT91C_BASE_TC1;
timer->TC_CCR = AT91C_TC_CLKDIS;
timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;
timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
/*
* Set up Timer 2 to use for measuring time between frames in
* tag simulation mode. Runs 4x faster as Timer 1
*/
AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC2);
prng_timer = AT91C_BASE_TC2;
prng_timer->TC_CCR = AT91C_TC_CLKDIS;
prng_timer->TC_CMR = AT91C_TC_CLKS_TIMER_DIV2_CLOCK;
prng_timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
}
/* At TIMER_CLOCK3 (MCK/32) */
#define RWD_TIME_1 150 /* RWD_TIME_PAUSE off, 80us on = 100us */
#define RWD_TIME_0 90 /* RWD_TIME_PAUSE off, 40us on = 60us */
#define RWD_TIME_PAUSE 30 /* 20us */
#define RWD_TIME_FUZZ 20 /* rather generous 13us, since the peak detector + hysteresis fuzz quite a bit */
#define TAG_TIME_BIT 150 /* 100us for every bit */
#define TAG_TIME_WAIT 490 /* time from RWD frame end to tag frame start, experimentally determined */
#define SIM_DIVISOR 586 /* prng_time/SIM_DIVISOR count prng needs to be forwared */
#define SIM_SHIFT 900 /* prng_time+SIM_SHIFT shift of delayed start */
#define SESSION_IV 0x55
#define OFFSET_LOG 1024
#define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
/* Generate Keystream */
static uint32_t get_key_stream(int skip, int count)
{
uint32_t key=0; int i;
/* Use int to enlarge timer tc to 32bit */
legic_prng_bc += prng_timer->TC_CV;
prng_timer->TC_CCR = AT91C_TC_SWTRG;
/* If skip == -1, forward prng time based */
if(skip == -1) {
i = (legic_prng_bc+SIM_SHIFT)/SIM_DIVISOR; /* Calculate Cycles based on timer */
i -= legic_prng_count(); /* substract cycles of finished frames */
i -= count; /* substract current frame length, rewidn to bedinning */
legic_prng_forward(i);
} else {
legic_prng_forward(skip);
}
/* Write Time Data into LOG */
uint8_t *BigBuf = BigBuf_get_addr();
i = (count == 6) ? -1 : legic_read_count;
BigBuf[OFFSET_LOG+128+i] = legic_prng_count();
BigBuf[OFFSET_LOG+256+i*4] = (legic_prng_bc >> 0) & 0xff;
BigBuf[OFFSET_LOG+256+i*4+1] = (legic_prng_bc >> 8) & 0xff;
BigBuf[OFFSET_LOG+256+i*4+2] = (legic_prng_bc >>16) & 0xff;
BigBuf[OFFSET_LOG+256+i*4+3] = (legic_prng_bc >>24) & 0xff;
BigBuf[OFFSET_LOG+384+i] = count;
/* Generate KeyStream */
for(i=0; i<count; i++) {
key |= legic_prng_get_bit() << i;
legic_prng_forward(1);
}
return key;
}
/* Send a frame in tag mode, the FPGA must have been set up by
* LegicRfSimulate
*/
static void frame_send_tag(uint16_t response, int bits, int crypt)
{
/* Bitbang the response */
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
/* Use time to crypt frame */
if(crypt) {
legic_prng_forward(2); /* TAG_TIME_WAIT -> shift by 2 */
int i; int key = 0;
for(i=0; i<bits; i++) {
key |= legic_prng_get_bit() << i;
legic_prng_forward(1);
}
//Dbprintf("key = 0x%x", key);
response = response ^ key;
}
/* Wait for the frame start */
while(timer->TC_CV < (TAG_TIME_WAIT - 30)) ;
int i;
for(i=0; i<bits; i++) {
int nextbit = timer->TC_CV + TAG_TIME_BIT;
int bit = response & 1;
response = response >> 1;
if(bit)
AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
else
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
while(timer->TC_CV < nextbit) ;
}
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
}
/* Send a frame in reader mode, the FPGA must have been set up by
* LegicRfReader
*/
static void frame_send_rwd(uint32_t data, int bits)
{
/* Start clock */
timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
int i;
for(i=0; i<bits; i++) {
int starttime = timer->TC_CV;
int pause_end = starttime + RWD_TIME_PAUSE, bit_end;
int bit = data & 1;
data = data >> 1;
if(bit ^ legic_prng_get_bit())
bit_end = starttime + RWD_TIME_1;
else
bit_end = starttime + RWD_TIME_0;
/* RWD_TIME_PAUSE time off, then some time on, so that the complete bit time is
* RWD_TIME_x, where x is the bit to be transmitted */
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
while(timer->TC_CV < pause_end) ;
AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
legic_prng_forward(1); /* bit duration is longest. use this time to forward the lfsr */
while(timer->TC_CV < bit_end);
}
/* One final pause to mark the end of the frame */
int pause_end = timer->TC_CV + RWD_TIME_PAUSE;
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
while(timer->TC_CV < pause_end) ;
AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
/* Reset the timer, to measure time until the start of the tag frame */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
}
/* Receive a frame from the card in reader emulation mode, the FPGA and
* timer must have been set up by LegicRfReader and frame_send_rwd.
*
* The LEGIC RF protocol from card to reader does not include explicit
* frame start/stop information or length information. The reader must
* know beforehand how many bits it wants to receive. (Notably: a card
* sending a stream of 0-bits is indistinguishable from no card present.)
*
* Receive methodology: There is a fancy correlator in hi_read_rx_xcorr, but
* I'm not smart enough to use it. Instead I have patched hi_read_tx to output
* the ADC signal with hysteresis on SSP_DIN. Bit-bang that signal and look
* for edges. Count the edges in each bit interval. If they are approximately
* 0 this was a 0-bit, if they are approximately equal to the number of edges
* expected for a 212kHz subcarrier, this was a 1-bit. For timing we use the
* timer that's still running from frame_send_rwd in order to get a synchronization
* with the frame that we just sent.
*
* FIXME: Because we're relying on the hysteresis to just do the right thing
* the range is severely reduced (and you'll probably also need a good antenna).
* So this should be fixed some time in the future for a proper receiver.
*/
static void frame_receive_rwd(struct legic_frame * const f, int bits, int crypt)
{
uint32_t the_bit = 1; /* Use a bitmask to save on shifts */
uint32_t data=0;
int i, old_level=0, edges=0;
int next_bit_at = TAG_TIME_WAIT;
if(bits > 32) {
bits = 32;
}
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
/* we have some time now, precompute the cipher
* since we cannot compute it on the fly while reading */
legic_prng_forward(2);
if(crypt) {
for(i=0; i<bits; i++) {
data |= legic_prng_get_bit() << i;
legic_prng_forward(1);
}
}
while(timer->TC_CV < next_bit_at) ;
next_bit_at += TAG_TIME_BIT;
for(i=0; i<bits; i++) {
edges = 0;
while(timer->TC_CV < next_bit_at) {
int level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
if(level != old_level)
edges++;
old_level = level;
}
next_bit_at += TAG_TIME_BIT;
if(edges > 20 && edges < 60) { /* expected are 42 edges */
data ^= the_bit;
}
the_bit <<= 1;
}
f->data = data;
f->bits = bits;
/* Reset the timer, to synchronize the next frame */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
}
static void frame_append_bit(struct legic_frame * const f, int bit)
{
if (f->bits >= 31)
return; /* Overflow, won't happen */
f->data |= (bit << f->bits);
f->bits++;
}
static void frame_clean(struct legic_frame * const f)
{
f->data = 0;
f->bits = 0;
}
static uint32_t perform_setup_phase_rwd(int iv)
{
/* Switch on carrier and let the tag charge for 1ms */
AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
SpinDelay(1);
legic_prng_init(0); /* no keystream yet */
frame_send_rwd(iv, 7);
legic_prng_init(iv);
frame_clean(&current_frame);
frame_receive_rwd(&current_frame, 6, 1);
legic_prng_forward(1); /* we wait anyways */
while(timer->TC_CV < 387) ; /* ~ 258us */
frame_send_rwd(0x19, 6);
return current_frame.data;
}
static void LegicCommonInit(void) {
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
FpgaSetupSsc();
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
/* Bitbang the transmitter */
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
setup_timer();
crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
}
/* Switch off carrier, make sure tag is reset */
static void switch_off_tag_rwd(void)
{
AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
SpinDelay(10);
WDT_HIT();
}
/* calculate crc for a legic command */
static int LegicCRC(int byte_index, int value, int cmd_sz) {
crc_clear(&legic_crc);
crc_update(&legic_crc, 1, 1); /* CMD_READ */
crc_update(&legic_crc, byte_index, cmd_sz-1);
crc_update(&legic_crc, value, 8);
return crc_finish(&legic_crc);
}
int legic_read_byte(int byte_index, int cmd_sz) {
int byte;
legic_prng_forward(4); /* we wait anyways */
while(timer->TC_CV < 387) ; /* ~ 258us + 100us*delay */
frame_send_rwd(1 | (byte_index << 1), cmd_sz);
frame_clean(&current_frame);
frame_receive_rwd(&current_frame, 12, 1);
byte = current_frame.data & 0xff;
if( LegicCRC(byte_index, byte, cmd_sz) != (current_frame.data >> 8) ) {
Dbprintf("!!! crc mismatch: expected %x but got %x !!!",
LegicCRC(byte_index, current_frame.data & 0xff, cmd_sz),
current_frame.data >> 8);
return -1;
}
return byte;
}
/* legic_write_byte() is not included, however it's trivial to implement
* and here are some hints on what remains to be done:
*
* * assemble a write_cmd_frame with crc and send it
* * wait until the tag sends back an ACK ('1' bit unencrypted)
* * forward the prng based on the timing
*/
//int legic_write_byte(int byte, int addr, int addr_sz, int PrngCorrection) {
int legic_write_byte(int byte, int addr, int addr_sz) {
//do not write UID, CRC
if(addr <= 0x04) {
return 0;
}
//== send write command ==============================
crc_clear(&legic_crc);
crc_update(&legic_crc, 0, 1); /* CMD_WRITE */
crc_update(&legic_crc, addr, addr_sz);
crc_update(&legic_crc, byte, 8);
uint32_t crc = crc_finish(&legic_crc);
uint32_t cmd = ((crc <<(addr_sz+1+8)) //CRC
|(byte <<(addr_sz+1)) //Data
|(addr <<1) //Address
|(0x00 <<0)); //CMD = W
uint32_t cmd_sz = addr_sz+1+8+4; //crc+data+cmd
legic_prng_forward(4); /* we wait anyways */
while(timer->TC_CV < 387) ; /* ~ 258us */
frame_send_rwd(cmd, cmd_sz);
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
//== wait for ack ====================================
int t, old_level=0, edges=0;
int next_bit_at =0;
while(timer->TC_CV < 387) ; /* ~ 258us */
for(t=0; t<80; t++) {
edges = 0;
next_bit_at += TAG_TIME_BIT;
while(timer->TC_CV < next_bit_at) {
int level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
if(level != old_level) {
edges++;
}
old_level = level;
}
if(edges > 20 && edges < 60) { /* expected are 42 edges */
int t = timer->TC_CV;
int c = t/TAG_TIME_BIT;
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
legic_prng_forward(c-1);
return 0;
}
}
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1) ; /* Wait till the clock has reset */
return -1;
}
int LegicRfReader(int offset, int bytes) {
// ice_legic_setup();
// ice_legic_select_card();
// return 0;
int byte_index=0, cmd_sz=0, card_sz=0;
LegicCommonInit();
uint8_t *BigBuf = BigBuf_get_addr();
memset(BigBuf, 0, 1024);
DbpString("setting up legic card");
uint32_t tag_type = perform_setup_phase_rwd(SESSION_IV);
switch_off_tag_rwd(); //we lose to mutch time with dprintf
switch(tag_type) {
case 0x0d:
DbpString("MIM22 card found, reading card ...");
cmd_sz = 6;
card_sz = 22;
break;
case 0x1d:
DbpString("MIM256 card found, reading card ...");
cmd_sz = 9;
card_sz = 256;
break;
case 0x3d:
DbpString("MIM1024 card found, reading card ...");
cmd_sz = 11;
card_sz = 1024;
break;
default:
Dbprintf("Unknown card format: %x",tag_type);
return -1;
}
if(bytes == -1)
bytes = card_sz;
if(bytes+offset >= card_sz)
bytes = card_sz-offset;
perform_setup_phase_rwd(SESSION_IV);
LED_B_ON();
while(byte_index < bytes) {
int r = legic_read_byte(byte_index+offset, cmd_sz);
if(r == -1 ||BUTTON_PRESS()) {
DbpString("operation aborted");
switch_off_tag_rwd();
LED_B_OFF();
LED_C_OFF();
return -1;
}
BigBuf[byte_index] = r;
WDT_HIT();
byte_index++;
if (byte_index & 0x10) LED_C_ON(); else LED_C_OFF();
}
LED_B_OFF();
LED_C_OFF();
switch_off_tag_rwd();
Dbprintf("Card read, use 'hf legic decode' or");
Dbprintf("'data hexsamples %d' to view results", (bytes+7) & ~7);
return 0;
}
/*int _LegicRfWriter(int bytes, int offset, int addr_sz, uint8_t *BigBuf, int RoundBruteforceValue) {
int byte_index=0;
LED_B_ON();
perform_setup_phase_rwd(SESSION_IV);
//legic_prng_forward(2);
while(byte_index < bytes) {
int r;
//check if the DCF should be changed
if ( (offset == 0x05) && (bytes == 0x02) ) {
//write DCF in reverse order (addr 0x06 before 0x05)
r = legic_write_byte(BigBuf[(0x06-byte_index)], (0x06-byte_index), addr_sz, RoundBruteforceValue);
//legic_prng_forward(1);
if(r == 0) {
byte_index++;
r = legic_write_byte(BigBuf[(0x06-byte_index)], (0x06-byte_index), addr_sz, RoundBruteforceValue);
}
//legic_prng_forward(1);
}
else {
r = legic_write_byte(BigBuf[byte_index+offset], byte_index+offset, addr_sz, RoundBruteforceValue);
}
if((r != 0) || BUTTON_PRESS()) {
Dbprintf("operation aborted @ 0x%03.3x", byte_index);
switch_off_tag_rwd();
LED_B_OFF();
LED_C_OFF();
return -1;
}
WDT_HIT();
byte_index++;
if(byte_index & 0x10) LED_C_ON(); else LED_C_OFF();
}
LED_B_OFF();
LED_C_OFF();
DbpString("write successful");
return 0;
}*/
void LegicRfWriter(int bytes, int offset) {
int byte_index=0, addr_sz=0;
uint8_t *BigBuf = BigBuf_get_addr();
LegicCommonInit();
DbpString("setting up legic card");
uint32_t tag_type = perform_setup_phase_rwd(SESSION_IV);
switch_off_tag_rwd();
switch(tag_type) {
case 0x0d:
if(offset+bytes > 22) {
Dbprintf("Error: can not write to 0x%03.3x on MIM22", offset+bytes);
return;
}
addr_sz = 5;
Dbprintf("MIM22 card found, writing 0x%02.2x - 0x%02.2x ...", offset, offset+bytes);
break;
case 0x1d:
if(offset+bytes > 0x100) {
Dbprintf("Error: can not write to 0x%03.3x on MIM256", offset+bytes);
return;
}
addr_sz = 8;
Dbprintf("MIM256 card found, writing 0x%02.2x - 0x%02.2x ...", offset, offset+bytes);
break;
case 0x3d:
if(offset+bytes > 0x400) {
Dbprintf("Error: can not write to 0x%03.3x on MIM1024", offset+bytes);
return;
}
addr_sz = 10;
Dbprintf("MIM1024 card found, writing 0x%03.3x - 0x%03.3x ...", offset, offset+bytes);
break;
default:
Dbprintf("No or unknown card found, aborting");
return;
}
#if 1
LED_B_ON();
perform_setup_phase_rwd(SESSION_IV);
while(byte_index < bytes) {
int r;
//check if the DCF should be changed
if ( ((byte_index+offset) == 0x05) && (bytes >= 0x02) ) {
//write DCF in reverse order (addr 0x06 before 0x05)
r = legic_write_byte(BigBuf[(0x06-byte_index)], (0x06-byte_index), addr_sz);
// write second byte on success...
if(r == 0) {
byte_index++;
r = legic_write_byte(BigBuf[(0x06-byte_index)], (0x06-byte_index), addr_sz);
}
}
else {
r = legic_write_byte(BigBuf[byte_index+offset], byte_index+offset, addr_sz);
}
if((r != 0) || BUTTON_PRESS()) {
Dbprintf("operation aborted @ 0x%03.3x", byte_index);
switch_off_tag_rwd();
LED_B_OFF();
LED_C_OFF();
return;
}
WDT_HIT();
byte_index++;
if(byte_index & 0x10) LED_C_ON(); else LED_C_OFF();
}
LED_B_OFF();
LED_C_OFF();
DbpString("write successful");
#else
for(byte_index = -2; byte_index < 200; byte_index++)
{
Dbprintf("+ Try RndValue %d...", byte_index);
if(_LegicRfWriter(bytes, offset, addr_sz, BigBuf, byte_index) == 0)
break;
}
#endif
}
void LegicRfRawWriter(int offset, int byte) {
int byte_index=0, addr_sz=0;
LegicCommonInit();
DbpString("setting up legic card");
uint32_t tag_type = perform_setup_phase_rwd(SESSION_IV);
switch_off_tag_rwd();
switch(tag_type) {
case 0x0d:
if(offset > 22) {
Dbprintf("Error: can not write to 0x%03.3x on MIM22", offset);
return;
}
addr_sz = 5;
Dbprintf("MIM22 card found, writing at addr 0x%02.2x - value 0x%02.2x ...", offset, byte);
break;
case 0x1d:
if(offset > 0x100) {
Dbprintf("Error: can not write to 0x%03.3x on MIM256", offset);
return;
}
addr_sz = 8;
Dbprintf("MIM256 card found, writing at addr 0x%02.2x - value 0x%02.2x ...", offset, byte);
break;
case 0x3d:
if(offset > 0x400) {
Dbprintf("Error: can not write to 0x%03.3x on MIM1024", offset);
return;
}
addr_sz = 10;
Dbprintf("MIM1024 card found, writing at addr 0x%03.3x - value 0x%03.3x ...", offset, byte);
break;
default:
Dbprintf("No or unknown card found, aborting");
return;
}
Dbprintf("integer value: %d offset: %d addr_sz: %d", byte, offset, addr_sz);
LED_B_ON();
perform_setup_phase_rwd(SESSION_IV);
//legic_prng_forward(2);
int r = legic_write_byte(byte, offset, addr_sz);
if((r != 0) || BUTTON_PRESS()) {
Dbprintf("operation aborted @ 0x%03.3x (%1d)", byte_index, r);
switch_off_tag_rwd();
LED_B_OFF();
LED_C_OFF();
return;
}
LED_B_OFF();
LED_C_OFF();
DbpString("write successful");
}
int timestamp;
/* Handle (whether to respond) a frame in tag mode */
static void frame_handle_tag(struct legic_frame const * const f)
{
uint8_t *BigBuf = BigBuf_get_addr();
/* First Part of Handshake (IV) */
if(f->bits == 7) {
if(f->data == SESSION_IV) {
LED_C_ON();
prng_timer->TC_CCR = AT91C_TC_SWTRG;
legic_prng_init(f->data);
frame_send_tag(0x3d, 6, 1); /* 0x3d^0x26 = 0x1b */
legic_state = STATE_IV;
legic_read_count = 0;
legic_prng_bc = 0;
legic_prng_iv = f->data;
/* TIMEOUT */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1);
while(timer->TC_CV < 280);
return;
} else if((prng_timer->TC_CV % 50) > 40) {
legic_prng_init(f->data);
frame_send_tag(0x3d, 6, 1);
SpinDelay(20);
return;
}
}
/* 0x19==??? */
if(legic_state == STATE_IV) {
if((f->bits == 6) && (f->data == (0x19 ^ get_key_stream(1, 6)))) {
legic_state = STATE_CON;
/* TIMEOUT */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1);
while(timer->TC_CV < 200);
return;
} else {
legic_state = STATE_DISCON;
LED_C_OFF();
Dbprintf("0x19 - Frame: %03.3x", f->data);
return;
}
}
/* Read */
if(f->bits == 11) {
if(legic_state == STATE_CON) {
int key = get_key_stream(-1, 11); //legic_phase_drift, 11);
int addr = f->data ^ key; addr = addr >> 1;
int data = BigBuf[addr];
int hash = LegicCRC(addr, data, 11) << 8;
BigBuf[OFFSET_LOG+legic_read_count] = (uint8_t)addr;
legic_read_count++;
//Dbprintf("Data:%03.3x, key:%03.3x, addr: %03.3x, read_c:%u", f->data, key, addr, read_c);
legic_prng_forward(legic_reqresp_drift);
frame_send_tag(hash | data, 12, 1);
/* SHORT TIMEOUT */
timer->TC_CCR = AT91C_TC_SWTRG;
while(timer->TC_CV > 1);
legic_prng_forward(legic_frame_drift);
while(timer->TC_CV < 180);
return;
}
}
/* Write */
if(f->bits == 23) {
int key = get_key_stream(-1, 23); //legic_frame_drift, 23);
int addr = f->data ^ key; addr = addr >> 1; addr = addr & 0x3ff;
int data = f->data ^ key; data = data >> 11; data = data & 0xff;
/* write command */
legic_state = STATE_DISCON;
LED_C_OFF();
Dbprintf("write - addr: %x, data: %x", addr, data);
return;
}
if(legic_state != STATE_DISCON) {
Dbprintf("Unexpected: sz:%u, Data:%03.3x, State:%u, Count:%u", f->bits, f->data, legic_state, legic_read_count);
int i;
Dbprintf("IV: %03.3x", legic_prng_iv);
for(i = 0; i<legic_read_count; i++) {
Dbprintf("Read Nb: %u, Addr: %u", i, BigBuf[OFFSET_LOG+i]);
}
for(i = -1; i<legic_read_count; i++) {
uint32_t t;
t = BigBuf[OFFSET_LOG+256+i*4];
t |= BigBuf[OFFSET_LOG+256+i*4+1] << 8;
t |= BigBuf[OFFSET_LOG+256+i*4+2] <<16;
t |= BigBuf[OFFSET_LOG+256+i*4+3] <<24;
Dbprintf("Cycles: %u, Frame Length: %u, Time: %u",
BigBuf[OFFSET_LOG+128+i],
BigBuf[OFFSET_LOG+384+i],
t);
}
}
legic_state = STATE_DISCON;
legic_read_count = 0;
SpinDelay(10);
LED_C_OFF();
return;
}
/* Read bit by bit untill full frame is received
* Call to process frame end answer
*/
static void emit(int bit)
{
if(bit == -1) {
if(current_frame.bits <= 4) {
frame_clean(&current_frame);
} else {
frame_handle_tag(&current_frame);
frame_clean(&current_frame);
}
WDT_HIT();
} else if(bit == 0) {
frame_append_bit(&current_frame, 0);
} else if(bit == 1) {
frame_append_bit(&current_frame, 1);
}
}
void LegicRfSimulate(int phase, int frame, int reqresp)
{
/* ADC path high-frequency peak detector, FPGA in high-frequency simulator mode,
* modulation mode set to 212kHz subcarrier. We are getting the incoming raw
* envelope waveform on DIN and should send our response on DOUT.
*
* The LEGIC RF protocol is pulse-pause-encoding from reader to card, so we'll
* measure the time between two rising edges on DIN, and no encoding on the
* subcarrier from card to reader, so we'll just shift out our verbatim data
* on DOUT, 1 bit is 100us. The time from reader to card frame is still unclear,
* seems to be 300us-ish.
*/
if(phase < 0) {
int i;
for(i=0; i<=reqresp; i++) {
legic_prng_init(SESSION_IV);
Dbprintf("i=%u, key 0x%3.3x", i, get_key_stream(i, frame));
}
return;
}
legic_phase_drift = phase;
legic_frame_drift = frame;
legic_reqresp_drift = reqresp;
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
FpgaSetupSsc();
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_212K);
/* Bitbang the receiver */
AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
setup_timer();
crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
int old_level = 0;
int active = 0;
legic_state = STATE_DISCON;
LED_B_ON();
DbpString("Starting Legic emulator, press button to end");
while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
int level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
int time = timer->TC_CV;
if(level != old_level) {
if(level == 1) {
timer->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
if(FUZZ_EQUAL(time, RWD_TIME_1, RWD_TIME_FUZZ)) {
/* 1 bit */
emit(1);
active = 1;
LED_A_ON();
} else if(FUZZ_EQUAL(time, RWD_TIME_0, RWD_TIME_FUZZ)) {
/* 0 bit */
emit(0);
active = 1;
LED_A_ON();
} else if(active) {
/* invalid */
emit(-1);
active = 0;
LED_A_OFF();
}
}
}
if(time >= (RWD_TIME_1+RWD_TIME_FUZZ) && active) {
/* Frame end */
emit(-1);
active = 0;
LED_A_OFF();
}
if(time >= (20*RWD_TIME_1) && (timer->TC_SR & AT91C_TC_CLKSTA)) {
timer->TC_CCR = AT91C_TC_CLKDIS;
}
old_level = level;
WDT_HIT();
}
DbpString("Stopped");
LED_B_OFF();
LED_A_OFF();
LED_C_OFF();
}
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
//-----------------------------------------------------------------------------
// Code up a string of octets at layer 2 (including CRC, we don't generate
// that here) so that they can be transmitted to the reader. Doesn't transmit
// them yet, just leaves them ready to send in ToSend[].
//-----------------------------------------------------------------------------
// static void CodeLegicAsTag(const uint8_t *cmd, int len)
// {
// int i;
// ToSendReset();
// // Transmit a burst of ones, as the initial thing that lets the
// // reader get phase sync. This (TR1) must be > 80/fs, per spec,
// // but tag that I've tried (a Paypass) exceeds that by a fair bit,
// // so I will too.
// for(i = 0; i < 20; i++) {
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// }
// // Send SOF.
// for(i = 0; i < 10; i++) {
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// }
// for(i = 0; i < 2; i++) {
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// }
// for(i = 0; i < len; i++) {
// int j;
// uint8_t b = cmd[i];
// // Start bit
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// // Data bits
// for(j = 0; j < 8; j++) {
// if(b & 1) {
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// } else {
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// }
// b >>= 1;
// }
// // Stop bit
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// }
// // Send EOF.
// for(i = 0; i < 10; i++) {
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// ToSendStuffBit(0);
// }
// for(i = 0; i < 2; i++) {
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// ToSendStuffBit(1);
// }
// // Convert from last byte pos to length
// ToSendMax++;
// }
//-----------------------------------------------------------------------------
// The software UART that receives commands from the reader, and its state
// variables.
//-----------------------------------------------------------------------------
static struct {
enum {
STATE_UNSYNCD,
STATE_GOT_FALLING_EDGE_OF_SOF,
STATE_AWAITING_START_BIT,
STATE_RECEIVING_DATA
} state;
uint16_t shiftReg;
int bitCnt;
int byteCnt;
int byteCntMax;
int posCnt;
uint8_t *output;
} 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 212kHz, 1/fs = 4,72us, i.e. function is called every 9,44us
*
* LED handling:
* LED A -> ON once we have received the SOF and are expecting the rest.
* LED A -> OFF once we have received EOF or are in error state or unsynced
*
* Returns: true if we received a EOF
* false if we are still waiting for some more
*/
// static RAMFUNC int HandleLegicUartBit(uint8_t bit)
// {
// switch(Uart.state) {
// case STATE_UNSYNCD:
// if(!bit) {
// // we went low, so this could be the beginning of an SOF
// Uart.state = STATE_GOT_FALLING_EDGE_OF_SOF;
// Uart.posCnt = 0;
// Uart.bitCnt = 0;
// }
// break;
// case STATE_GOT_FALLING_EDGE_OF_SOF:
// Uart.posCnt++;
// if(Uart.posCnt == 2) { // sample every 4 1/fs in the middle of a bit
// if(bit) {
// if(Uart.bitCnt > 9) {
// // we've seen enough consecutive
// // zeros that it's a valid SOF
// Uart.posCnt = 0;
// Uart.byteCnt = 0;
// Uart.state = STATE_AWAITING_START_BIT;
// LED_A_ON(); // Indicate we got a valid SOF
// } else {
// // didn't stay down long enough
// // before going high, error
// Uart.state = STATE_UNSYNCD;
// }
// } else {
// // do nothing, keep waiting
// }
// Uart.bitCnt++;
// }
// if(Uart.posCnt >= 4) Uart.posCnt = 0;
// if(Uart.bitCnt > 12) {
// // Give up if we see too many zeros without
// // a one, too.
// LED_A_OFF();
// Uart.state = STATE_UNSYNCD;
// }
// break;
// case STATE_AWAITING_START_BIT:
// Uart.posCnt++;
// if(bit) {
// 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_UNSYNCD;
// }
// } else {
// // falling edge, this starts the data byte
// Uart.posCnt = 0;
// Uart.bitCnt = 0;
// Uart.shiftReg = 0;
// Uart.state = STATE_RECEIVING_DATA;
// }
// break;
// case STATE_RECEIVING_DATA:
// Uart.posCnt++;
// if(Uart.posCnt == 2) {
// // time to sample a bit
// Uart.shiftReg >>= 1;
// if(bit) {
// Uart.shiftReg |= 0x200;
// }
// Uart.bitCnt++;
// }
// if(Uart.posCnt >= 4) {
// Uart.posCnt = 0;
// }
// if(Uart.bitCnt == 10) {
// if((Uart.shiftReg & 0x200) && !(Uart.shiftReg & 0x001))
// {
// // this is a data byte, with correct
// // start and stop bits
// Uart.output[Uart.byteCnt] = (Uart.shiftReg >> 1) & 0xff;
// Uart.byteCnt++;
// if(Uart.byteCnt >= Uart.byteCntMax) {
// // Buffer overflowed, give up
// LED_A_OFF();
// Uart.state = STATE_UNSYNCD;
// } else {
// // so get the next byte now
// Uart.posCnt = 0;
// Uart.state = STATE_AWAITING_START_BIT;
// }
// } else if (Uart.shiftReg == 0x000) {
// // this is an EOF byte
// LED_A_OFF(); // Finished receiving
// Uart.state = STATE_UNSYNCD;
// if (Uart.byteCnt != 0) {
// return TRUE;
// }
// } else {
// // this is an error
// LED_A_OFF();
// Uart.state = STATE_UNSYNCD;
// }
// }
// break;
// default:
// LED_A_OFF();
// Uart.state = STATE_UNSYNCD;
// break;
// }
// return FALSE;
// }
static void UartReset()
{
Uart.byteCntMax = MAX_FRAME_SIZE;
Uart.state = STATE_UNSYNCD;
Uart.byteCnt = 0;
Uart.bitCnt = 0;
Uart.posCnt = 0;
memset(Uart.output, 0x00, MAX_FRAME_SIZE);
}
// static void UartInit(uint8_t *data)
// {
// Uart.output = data;
// UartReset();
// }
//=============================================================================
// An LEGIC reader. We take layer two commands, code them
// appropriately, and then send them to the tag. We then listen for the
// tag's response, which we leave in the buffer to be demodulated on the
// PC side.
//=============================================================================
static struct {
enum {
DEMOD_UNSYNCD,
DEMOD_PHASE_REF_TRAINING,
DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
DEMOD_GOT_FALLING_EDGE_OF_SOF,
DEMOD_AWAITING_START_BIT,
DEMOD_RECEIVING_DATA
} state;
int bitCount;
int posCount;
int thisBit;
uint16_t shiftReg;
uint8_t *output;
int len;
int sumI;
int sumQ;
} Demod;
/*
* Handles reception of a bit from the tag
*
* This function is called 2 times per bit (every 4 subcarrier cycles).
* Subcarrier frequency fs is 212kHz, 1/fs = 4,72us, i.e. function is called every 9,44us
*
* 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
*
* Returns: true if we received a EOF
* false if we are still waiting for some more
*
*/
#ifndef SUBCARRIER_DETECT_THRESHOLD
# define SUBCARRIER_DETECT_THRESHOLD 8
#endif
// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
#ifndef CHECK_FOR_SUBCARRIER
# define CHECK_FOR_SUBCARRIER() { v = MAX(ai, aq) + MIN(halfci, halfcq); }
#endif
// The soft decision on the bit uses an estimate of just the
// quadrant of the reference angle, not the exact angle.
// Subcarrier amplitude v = sqrt(ci^2 + cq^2), approximated here by max(abs(ci),abs(cq)) + 1/2*min(abs(ci),abs(cq)))
#define MAKE_SOFT_DECISION() { \
if(Demod.sumI > 0) \
v = ci; \
else \
v = -ci; \
\
if(Demod.sumQ > 0) \
v += cq; \
else \
v -= cq; \
\
}
static RAMFUNC int HandleLegicSamplesDemod(int ci, int cq)
{
int v = 0;
int ai = ABS(ci);
int aq = ABS(cq);
int halfci = (ai >> 1);
int halfcq = (aq >> 1);
switch(Demod.state) {
case DEMOD_UNSYNCD:
CHECK_FOR_SUBCARRIER()
if(v > SUBCARRIER_DETECT_THRESHOLD) { // subcarrier detected
Demod.state = DEMOD_PHASE_REF_TRAINING;
Demod.sumI = ci;
Demod.sumQ = cq;
Demod.posCount = 1;
}
break;
case DEMOD_PHASE_REF_TRAINING:
if(Demod.posCount < 8) {
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;
}
break;
case DEMOD_AWAITING_FALLING_EDGE_OF_SOF:
MAKE_SOFT_DECISION()
//Dbprintf("ICE: %d %d %d %d %d", v, Demod.sumI, Demod.sumQ, ci, cq );
// logic '0' detected
if (v <= 0) {
Demod.state = DEMOD_GOT_FALLING_EDGE_OF_SOF;
// start of SOF sequence
Demod.posCount = 0;
} else {
// maximum length of TR1 = 200 1/fs
if(Demod.posCount > 25*2) Demod.state = DEMOD_UNSYNCD;
}
++Demod.posCount;
break;
case DEMOD_GOT_FALLING_EDGE_OF_SOF:
++Demod.posCount;
MAKE_SOFT_DECISION()
if(v > 0) {
// low phase of SOF too short (< 9 etu). Note: spec is >= 10, but FPGA tends to "smear" edges
if(Demod.posCount < 10*2) {
Demod.state = DEMOD_UNSYNCD;
} else {
LED_C_ON(); // Got SOF
Demod.state = DEMOD_AWAITING_START_BIT;
Demod.posCount = 0;
Demod.len = 0;
}
} else {
// low phase of SOF too long (> 12 etu)
if(Demod.posCount > 13*2) {
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
}
}
break;
case DEMOD_AWAITING_START_BIT:
++Demod.posCount;
MAKE_SOFT_DECISION()
if(v > 0) {
// max 19us between characters = 16 1/fs, max 3 etu after low phase of SOF = 24 1/fs
if(Demod.posCount > 3*2) {
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
}
} else {
// start bit detected
Demod.bitCount = 0;
Demod.posCount = 1; // this was the first half
Demod.thisBit = v;
Demod.shiftReg = 0;
Demod.state = DEMOD_RECEIVING_DATA;
}
break;
case DEMOD_RECEIVING_DATA:
MAKE_SOFT_DECISION()
if(Demod.posCount == 0) {
// first half of bit
Demod.thisBit = v;
Demod.posCount = 1;
} else {
// second half of bit
Demod.thisBit += v;
Demod.shiftReg >>= 1;
// logic '1'
if(Demod.thisBit > 0)
Demod.shiftReg |= 0x200;
++Demod.bitCount;
if(Demod.bitCount == 10) {
uint16_t s = Demod.shiftReg;
if((s & 0x200) && !(s & 0x001)) {
// stop bit == '1', start bit == '0'
uint8_t b = (s >> 1);
Demod.output[Demod.len] = b;
++Demod.len;
Demod.state = DEMOD_AWAITING_START_BIT;
} else {
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
if(s == 0x000) {
// This is EOF (start, stop and all data bits == '0'
return TRUE;
}
}
}
Demod.posCount = 0;
}
break;
default:
Demod.state = DEMOD_UNSYNCD;
LED_C_OFF();
break;
}
return FALSE;
}
// Clear out the state of the "UART" that receives from the tag.
static void DemodReset() {
Demod.len = 0;
Demod.state = DEMOD_UNSYNCD;
Demod.posCount = 0;
Demod.sumI = 0;
Demod.sumQ = 0;
Demod.bitCount = 0;
Demod.thisBit = 0;
Demod.shiftReg = 0;
memset(Demod.output, 0x00, MAX_FRAME_SIZE);
}
static void DemodInit(uint8_t *data) {
Demod.output = data;
DemodReset();
}
/*
* Demodulate the samples we received from the tag, also log to tracebuffer
* quiet: set to 'TRUE' to disable debug output
*/
#define LEGIC_DMA_BUFFER_SIZE 256
static void GetSamplesForLegicDemod(int n, bool quiet)
{
int max = 0;
bool gotFrame = FALSE;
int lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
int ci, cq, samples = 0;
BigBuf_free();
// And put the FPGA in the appropriate mode
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_QUARTER_FREQ);
// The response (tag -> reader) that we're receiving.
// Set up the demodulator for tag -> reader responses.
DemodInit(BigBuf_malloc(MAX_FRAME_SIZE));
// The DMA buffer, used to stream samples from the FPGA
int8_t *dmaBuf = (int8_t*) BigBuf_malloc(LEGIC_DMA_BUFFER_SIZE);
int8_t *upTo = dmaBuf;
// Setup and start DMA.
if ( !FpgaSetupSscDma((uint8_t*) dmaBuf, LEGIC_DMA_BUFFER_SIZE) ){
if (MF_DBGLEVEL > 1) Dbprintf("FpgaSetupSscDma failed. Exiting");
return;
}
// Signal field is ON with the appropriate LED:
LED_D_ON();
for(;;) {
int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
if(behindBy > max) max = behindBy;
while(((lastRxCounter-AT91C_BASE_PDC_SSC->PDC_RCR) & (LEGIC_DMA_BUFFER_SIZE-1)) > 2) {
ci = upTo[0];
cq = upTo[1];
upTo += 2;
if(upTo >= dmaBuf + LEGIC_DMA_BUFFER_SIZE) {
upTo = dmaBuf;
AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) upTo;
AT91C_BASE_PDC_SSC->PDC_RNCR = LEGIC_DMA_BUFFER_SIZE;
}
lastRxCounter -= 2;
if(lastRxCounter <= 0)
lastRxCounter = LEGIC_DMA_BUFFER_SIZE;
samples += 2;
gotFrame = HandleLegicSamplesDemod(ci , cq );
if ( gotFrame )
break;
}
if(samples > n || gotFrame)
break;
}
FpgaDisableSscDma();
if (!quiet && Demod.len == 0) {
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 (Demod.len > 0) {
uint8_t parity[MAX_PARITY_SIZE] = {0x00};
LogTrace(Demod.output, Demod.len, 0, 0, parity, FALSE);
}
}
//-----------------------------------------------------------------------------
// Transmit the command (to the tag) that was placed in ToSend[].
//-----------------------------------------------------------------------------
static void TransmitForLegic(void)
{
int c;
FpgaSetupSsc();
while(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))
AT91C_BASE_SSC->SSC_THR = 0xff;
// Signal field is ON with the appropriate Red LED
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);
for(c = 0; c < 10;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = 0xff;
c++;
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
(void)r;
}
WDT_HIT();
}
c = 0;
for(;;) {
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
AT91C_BASE_SSC->SSC_THR = ToSend[c];
legic_prng_forward(1); // forward the lfsr
c++;
if(c >= ToSendMax) {
break;
}
}
if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
(void)r;
}
WDT_HIT();
}
LED_B_OFF();
}
//-----------------------------------------------------------------------------
// Code a layer 2 command (string of octets, including CRC) into ToSend[],
// so that it is ready to transmit to the tag using TransmitForLegic().
//-----------------------------------------------------------------------------
static void CodeLegicBitsAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
{
int i, j;
uint8_t b;
ToSendReset();
// Send SOF
for(i = 0; i < 7; i++)
ToSendStuffBit(1);
for(i = 0; i < cmdlen; i++) {
// Start bit
ToSendStuffBit(0);
// Data bits
b = cmd[i];
for(j = 0; j < bits; j++) {
if(b & 1) {
ToSendStuffBit(1);
} else {
ToSendStuffBit(0);
}
b >>= 1;
}
}
// Convert from last character reference to length
++ToSendMax;
}
/**
Convenience function to encode, transmit and trace Legic comms
**/
static void CodeAndTransmitLegicAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
{
CodeLegicBitsAsReader(cmd, cmdlen, bits);
TransmitForLegic();
if (tracing) {
uint8_t parity[1] = {0x00};
LogTrace(cmd, cmdlen, 0, 0, parity, TRUE);
}
}
int ice_legic_select_card()
{
//int cmd_size=0, card_size=0;
uint8_t wakeup[] = { 0x7F };
uint8_t getid[] = {0x19};
legic_prng_init(SESSION_IV);
// first, wake up the tag, 7bits
CodeAndTransmitLegicAsReader(wakeup, sizeof(wakeup), 7);
GetSamplesForLegicDemod(1000, TRUE);
// frame_clean(&current_frame);
//frame_receive_rwd(&current_frame, 6, 1);
legic_prng_forward(1); /* we wait anyways */
//while(timer->TC_CV < 387) ; /* ~ 258us */
//frame_send_rwd(0x19, 6);
CodeAndTransmitLegicAsReader(getid, sizeof(getid), 8);
GetSamplesForLegicDemod(1000, TRUE);
//if (Demod.len < 14) return 2;
Dbprintf("CARD TYPE: %02x LEN: %d", Demod.output[0], Demod.len);
switch(Demod.output[0]) {
case 0x1d:
DbpString("MIM 256 card found");
// cmd_size = 9;
// card_size = 256;
break;
case 0x3d:
DbpString("MIM 1024 card found");
// cmd_size = 11;
// card_size = 1024;
break;
default:
return -1;
}
// if(bytes == -1)
// bytes = card_size;
// if(bytes + offset >= card_size)
// bytes = card_size - offset;
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
set_tracing(FALSE);
return 1;
}
// Set up LEGIC communication
void ice_legic_setup() {
// standard things.
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
BigBuf_free(); BigBuf_Clear_ext(false);
clear_trace();
set_tracing(TRUE);
DemodReset();
UartReset();
// Set up the synchronous serial port
FpgaSetupSsc();
// connect Demodulated Signal to ADC:
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// Signal field is on with the appropriate LED
LED_D_ON();
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX | FPGA_HF_READER_TX_SHALLOW_MOD);
SpinDelay(200);
// Start the timer
//StartCountSspClk();
// initalize CRC
crc_init(&legic_crc, 4, 0x19 >> 1, 0x5, 0);
// initalize prng
legic_prng_init(0);
}
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