X-Git-Url: http://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/2561caa24c84be1f93649a8c5abce0fabe29a5d5..b642ce7ab58f1f91dc2edc04fbe6f2bf4f8b9afd:/armsrc/legicrf.c diff --git a/armsrc/legicrf.c b/armsrc/legicrf.c index 86c0c360..27dcc297 100644 --- a/armsrc/legicrf.c +++ b/armsrc/legicrf.c @@ -1,21 +1,44 @@ -/* - * LEGIC RF simulation code - * - * (c) 2009 Henryk Plötz - */ - -#include +//----------------------------------------------------------------------------- +// (c) 2009 Henryk Plötz +// +// 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 "unistd.h" -#include "stdint.h" +#include "legic_prng.h" +#include "crc.h" static struct legic_frame { int bits; - uint16_t data; + 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) { @@ -25,9 +48,20 @@ static void setup_timer(void) AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1); timer = AT91C_BASE_TC1; timer->TC_CCR = AT91C_TC_CLKDIS; - timer->TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK3; + 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 */ @@ -36,40 +70,123 @@ static void setup_timer(void) #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(); + if(count == 6) { i = -1; } else { i = 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; iPIO_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; iTC_CV < (TAG_TIME_WAIT - 30)) ; + + int i; + for(i=0; iTC_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(uint16_t data, int bits) +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; iTC_CV; int pause_end = starttime + RWD_TIME_PAUSE, bit_end; int bit = data & 1; data = data >> 1; - - if(bit) { + + 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; @@ -77,7 +194,7 @@ static void frame_send_rwd(uint16_t data, int bits) 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 */ @@ -85,12 +202,12 @@ static void frame_send_rwd(uint16_t data, int bits) /* 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 @@ -99,28 +216,41 @@ static void frame_send_rwd(uint16_t data, int bits) * 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 + * + * 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. + * 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) +static void frame_receive_rwd(struct legic_frame * const f, int bits, int crypt) { - uint16_t the_bit = 1; /* Use a bitmask to save on shifts */ - uint16_t data=0; + 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 > 16) - bits = 16; + 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; iTC_CV < next_bit_at) ; + next_bit_at += TAG_TIME_BIT; - + for(i=0; iTC_CV < next_bit_at) { @@ -132,121 +262,498 @@ static void frame_receive_rwd(struct legic_frame * const f, int bits) next_bit_at += TAG_TIME_BIT; if(edges > 20 && edges < 60) { /* expected are 42 edges */ - data |= the_bit; + 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<bits); + f->bits++; +} + static void frame_clean(struct legic_frame * const f) { f->data = 0; f->bits = 0; } -static uint16_t perform_setup_phase_rwd(void) +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); - - frame_send_rwd(0x55, 7); + + legic_prng_init(0); /* no keystream yet */ + frame_send_rwd(iv, 7); + legic_prng_init(iv); + frame_clean(¤t_frame); - frame_receive_rwd(¤t_frame, 6); + frame_receive_rwd(¤t_frame, 6, 1); + legic_prng_forward(1); /* we wait anyways */ while(timer->TC_CV < 387) ; /* ~ 258us */ - frame_send_rwd(0x019, 6); - - return current_frame.data ^ 0x26; -} + frame_send_rwd(0x19, 6); -static void switch_off_tag_rwd(void) -{ - /* Switch off carrier, make sure tag is reset */ - AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT; - SpinDelay(10); - - WDT_HIT(); + return current_frame.data; } -void LegicRfReader(void) -{ +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); +} + +static void switch_off_tag_rwd(void) +{ + /* Switch off carrier, make sure tag is reset */ + 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(¤t_frame); + + frame_receive_rwd(¤t_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) { + //do not write UID, CRC, DCF + if(addr <= 0x06) { + 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(2); /* we wait anyways */ + while(timer->TC_CV < 387) {}; /* ~ 258us */ + frame_send_rwd(cmd, cmd_sz); + + //== 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); + 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) { + int byte_index=0, cmd_sz=0, card_sz=0; + + LegicCommonInit(); + + uint8_t *BigBuf = BigBuf_get_addr(); memset(BigBuf, 0, 1024); - - int byte_index = 0, card_size = 0, command_size = 0; - uint16_t command_obfuscation = 0x57, response_obfuscation = 0; - uint16_t tag_type = perform_setup_phase_rwd(); - switch_off_tag_rwd(); - - int error = 0; + + 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 0x1d: - DbpString("MIM 256 card found, reading card ..."); - command_size = 9; - card_size = 256; - response_obfuscation = 0x52; - break; - case 0x3d: - DbpString("MIM 1024 card found, reading card ..."); - command_size = 11; - card_size = 1024; - response_obfuscation = 0xd4; - break; - default: - DbpString("No or unknown card found, aborting"); - error = 1; - break; + case 0x1d: + DbpString("MIM 256 card found, reading card ..."); + cmd_sz = 9; + card_sz = 256; + break; + case 0x3d: + DbpString("MIM 1024 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(!BUTTON_PRESS() && (byte_indexTC_CV < 387) ; /* ~ 258us */ - frame_send_rwd(command_obfuscation ^ (byte_index<<1), command_size); - frame_clean(¤t_frame); - frame_receive_rwd(¤t_frame, 8); - ((uint8_t*)BigBuf)[byte_index] = (current_frame.data ^ response_obfuscation) & 0xff; - - switch_off_tag_rwd(); - - WDT_HIT(); + BigBuf[byte_index] = r; + WDT_HIT(); byte_index++; - if(byte_index & 0x04) LED_C_ON(); else LED_C_OFF(); + if(byte_index & 0x10) LED_C_ON(); else LED_C_OFF(); } LED_B_OFF(); - LED_C_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; +} + +void LegicRfWriter(int bytes, int offset) { + int byte_index=0, addr_sz=0; + uint8_t *BigBuf = BigBuf_get_addr(); + + LegicCommonInit(); - if(!error) { - if(card_size == 256) { - DbpString("Card read, use hexsamples 256 to view results"); - } else if(card_size == 1024) { - DbpString("Card read, use hexsamples 1024 to view results"); + DbpString("setting up legic card"); + uint32_t tag_type = perform_setup_phase_rwd(SESSION_IV); + switch_off_tag_rwd(); + switch(tag_type) { + case 0x1d: + if(offset+bytes > 0x100) { + Dbprintf("Error: can not write to 0x%03.3x on MIM 256", offset+bytes); + return; + } + addr_sz = 8; + Dbprintf("MIM 256 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 MIM 1024", offset+bytes); + return; + } + addr_sz = 10; + Dbprintf("MIM 1024 card found, writing 0x%03.3x - 0x%03.3x ...", offset, offset+bytes); + break; + default: + Dbprintf("No or unknown card found, aborting"); + return; + } + + LED_B_ON(); + perform_setup_phase_rwd(SESSION_IV); + legic_prng_forward(2); + while(byte_index < bytes) { + int 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"); } + +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; iPIO_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()) { + 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(); +} +