Merge pull request #25 from drandreas/rdv4-legic

Legic Tag Simulator
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RFID Research Group 2018-09-06 20:26:39 +02:00 committed by GitHub
commit eb0b5116a2
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GPG key ID: 4AEE18F83AFDEB23
10 changed files with 546 additions and 58 deletions

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@ -54,7 +54,7 @@ SRC_FELICA = felica.c
SRC_CRAPTO1 = crypto1.c des.c aes.c desfire_key.c desfire_crypto.c mifaredesfire.c
SRC_CRC = crc.c crc16.c crc32.c
SRC_ICLASS = iclass.c optimized_cipher.c
SRC_LEGIC = legicrf.c legic_prng.c
SRC_LEGIC = legicrf.c legicrfsim.c legic_prng.c
SRC_BEE = bee.c
# RDV40 related hardware support

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@ -19,6 +19,7 @@
#include "printf.h"
#include "string.h"
#include "legicrf.h"
#include "legicrfsim.h"
#include "lfsampling.h"
#include "BigBuf.h"
#include "mifareutil.h"
@ -796,10 +797,10 @@ void UsbPacketReceived(uint8_t *packet, int len) {
#ifdef WITH_LEGICRF
case CMD_SIMULATE_TAG_LEGIC_RF:
LegicRfSimulate(c->arg[0], c->arg[1], c->arg[2]);
LegicRfSimulate(c->arg[0]);
break;
case CMD_WRITER_LEGIC_RF:
LegicRfWriter( c->arg[0], c->arg[1], c->arg[2], c->d.asBytes);
LegicRfWriter(c->arg[0], c->arg[1], c->arg[2], c->d.asBytes);
break;
case CMD_READER_LEGIC_RF:
LegicRfReader(c->arg[0], c->arg[1], c->arg[2]);

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@ -1,7 +1,7 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2016 Iceman
// 2018 AntiCat (rwd rewritten)
// 2018 AntiCat
//
// 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
@ -16,7 +16,7 @@
#include "legic_prng.h" /* legic PRNG impl */
#include "legic.h" /* legic_card_select_t struct */
static uint8_t* legic_mem; /* card memory, used for read, write and sim */
static uint8_t* legic_mem; /* card memory, used for read, write */
static legic_card_select_t card;/* metadata of currently selected card */
static crc_t legic_crc;
@ -179,7 +179,7 @@ static uint32_t rx_frame(uint8_t len) {
uint32_t last_frame_start = last_frame_end;
uint32_t frame = 0;
for(uint8_t i = 0; i < len; i++) {
for(uint8_t i = 0; i < len; ++i) {
frame |= (rx_bit() ^ legic_prng_get_bit()) << i;
legic_prng_forward(1);
@ -235,7 +235,7 @@ static bool rx_ack() {
// Legic Reader
//-----------------------------------------------------------------------------
int init_card(uint8_t cardtype, legic_card_select_t *p_card) {
static int init_card(uint8_t cardtype, legic_card_select_t *p_card) {
p_card->tagtype = cardtype;
switch(p_card->tagtype) {
@ -302,8 +302,8 @@ static void init_reader(bool clear_mem) {
// The setup consists of a three way handshake:
// - Transmit initialisation vector 7 bits
// - Receive card type 6 bits
// - Acknowledge frame 6 bits
static uint32_t setup_phase_reader(uint8_t iv) {
// - Transmit Acknowledge 6 bits
static uint32_t setup_phase(uint8_t iv) {
// init coordination timestamp
last_frame_end = GET_TICKS;
@ -314,7 +314,7 @@ static uint32_t setup_phase_reader(uint8_t iv) {
legic_prng_init(0);
tx_frame(iv, 7);
// configure iv
// configure prng
legic_prng_init(iv);
legic_prng_forward(2);
@ -398,7 +398,7 @@ void LegicRfInfo(void) {
init_reader(false);
// establish shared secret and detect card type
uint8_t card_type = setup_phase_reader(0x01);
uint8_t card_type = setup_phase(0x01);
if(init_card(card_type, &card) != 0) {
cmd_send(CMD_ACK, 0, 0, 0, 0, 0);
goto OUT;
@ -435,7 +435,7 @@ void LegicRfReader(uint16_t offset, uint16_t len, uint8_t iv) {
init_reader(false);
// establish shared secret and detect card type
uint8_t card_type = setup_phase_reader(iv);
uint8_t card_type = setup_phase(iv);
if(init_card(card_type, &card) != 0) {
cmd_send(CMD_ACK, 0, 0, 0, 0, 0);
goto OUT;
@ -474,7 +474,7 @@ void LegicRfWriter(uint16_t offset, uint16_t len, uint8_t iv, uint8_t *data) {
}
// establish shared secret and detect card type
uint8_t card_type = setup_phase_reader(iv);
uint8_t card_type = setup_phase(iv);
if(init_card(card_type, &card) != 0) {
cmd_send(CMD_ACK, 0, 0, 0, 0, 0);
goto OUT;
@ -501,7 +501,3 @@ OUT:
switch_off();
StopTicks();
}
void LegicRfSimulate(int phase, int frame, int reqresp) {
cmd_send(CMD_ACK, 0, 0, 0, 0, 0); //TODO Implement
}

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@ -1,5 +1,6 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2018 AntiCat
//
// 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
@ -16,6 +17,5 @@
extern void LegicRfInfo(void);
extern void LegicRfReader(uint16_t offset, uint16_t len, uint8_t iv);
extern void LegicRfWriter(uint16_t offset, uint16_t byte, uint8_t iv, uint8_t *data);
extern void LegicRfSimulate(int phase, int frame, int reqresp);
#endif /* __LEGICRF_H */

486
armsrc/legicrfsim.c Normal file
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@ -0,0 +1,486 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2016 Iceman
// 2018 AntiCat
//
// 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 "legicrf.h"
#include "ticks.h" /* timers */
#include "crc.h" /* legic crc-4 */
#include "legic_prng.h" /* legic PRNG impl */
#include "legic.h" /* legic_card_select_t struct */
static uint8_t* legic_mem; /* card memory, used for sim */
static legic_card_select_t card;/* metadata of currently selected card */
static crc_t legic_crc;
//-----------------------------------------------------------------------------
// Frame timing and pseudorandom number generator
//
// The Prng is forwarded every 99.1us (TAG_BIT_PERIOD), except when the reader is
// transmitting. In that case the prng has to be forwarded every bit transmitted:
// - 31.3us for a 0 (RWD_TIME_0)
// - 99.1us for a 1 (RWD_TIME_1)
//
// The data dependent timing makes writing comprehensible code significantly
// harder. The current aproach forwards the prng data based if there is data on
// air and time based, using GetCountSspClk(), during computational and wait
// periodes. SSP Clock is clocked by the FPGA at 212 kHz (subcarrier frequency).
//
// To not have the necessity to calculate/guess exection time dependend timeouts
// tx_frame and rx_frame use a shared timestamp to coordinate tx and rx timeslots.
//-----------------------------------------------------------------------------
static uint32_t last_frame_end; /* ts of last bit of previews rx or tx frame */
#define TAG_FRAME_WAIT 70 /* 330us from READER frame end to TAG frame start */
#define TAG_ACK_WAIT 758 /* 3.57ms from READER frame end to TAG write ACK */
#define TAG_BIT_PERIOD 21 /* 99.1us */
#define RWD_TIME_PAUSE 4 /* 18.9us */
#define RWD_TIME_1 21 /* RWD_TIME_PAUSE 18.9us off + 80.2us on = 99.1us */
#define RWD_TIME_0 13 /* RWD_TIME_PAUSE 18.9us off + 42.4us on = 61.3us */
#define RWD_CMD_TIMEOUT 40 /* 40 * 99.1us (arbitrary value) */
#define RWD_MIN_FRAME_LEN 6 /* Shortest frame is 6 bits */
#define RWD_MAX_FRAME_LEN 23 /* Longest frame is 23 bits */
#define RWD_PULSE 1 /* Pulse is signaled with GPIO_SSC_DIN high */
#define RWD_PAUSE 0 /* Pause is signaled with GPIO_SSC_DIN low */
//-----------------------------------------------------------------------------
// Demodulation
//-----------------------------------------------------------------------------
// Returns true if a pulse/pause is received within timeout
static inline bool wait_for(bool value, const uint32_t timeout) {
while((bool)(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN) != value) {
if(GetCountSspClk() > timeout) {
return false;
}
}
return true;
}
// Returns a demedulated bit or -1 on code violation
//
// rx_bit decodes bits using a thresholds. rx_bit has to be called by as soon as
// a frame starts (first pause is received). rx_bit checks for a pause up to
// 18.9us followed by a pulse of 80.2us or 42.4us:
// - A bit length <18.9us is a code violation
// - A bit length >80.2us is a 1
// - A bit length <80.2us is a 0
// - A bit length >148.6us is a code violation
static inline int8_t rx_bit() {
// backup ts for threshold calculation
uint32_t bit_start = last_frame_end;
// wait for pause to end
if(!wait_for(RWD_PULSE, bit_start + RWD_TIME_1*3/2)) {
return -1;
}
// wait for next pause
if(!wait_for(RWD_PAUSE, bit_start + RWD_TIME_1*3/2)) {
return -1;
}
// update bit and frame end
last_frame_end = GetCountSspClk();
// check for code violation (bit to short)
if(last_frame_end - bit_start < RWD_TIME_PAUSE) {
return -1;
}
// apply threshold (average of RWD_TIME_0 and )
return (last_frame_end - bit_start > (RWD_TIME_0 + RWD_TIME_1) / 2);
}
//-----------------------------------------------------------------------------
// Modulation
//
// LEGIC RF uses a very basic load modulation from card to reader:
// - Subcarrier on for a 1
// - Subcarrier off for for a 0
//
// The 212kHz subcarrier is generated by the FPGA as well as a mathcing ssp clk.
// Each bit is transfered in a 99.1us slot and the first timeslot starts 330us
// after the final 20us pause generated by the reader.
//-----------------------------------------------------------------------------
// Transmits a bit
//
// Note: The Subcarrier is not disabled during bits to prevent glitches. This is
// not mandatory but results in a cleaner signal. tx_frame will disable
// the subcarrier when the frame is done.
static inline void tx_bit(bool bit) {
LED_C_ON();
if(bit) {
// modulate subcarrier
HIGH(GPIO_SSC_DOUT);
} else {
// do not modulate subcarrier
LOW(GPIO_SSC_DOUT);
}
// wait for tx timeslot to end
last_frame_end += TAG_BIT_PERIOD;
while(GetCountSspClk() < last_frame_end) { };
LED_C_OFF();
}
//-----------------------------------------------------------------------------
// Frame Handling
//
// The LEGIC RF protocol from reader to card does not include explicit frame
// start/stop information or length information. The tag detects end of frame
// trough an extended pulse (>99.1us) without a pause.
// In reverse direction (card to reader) the number of bites is well known
// and depends only the command received (IV, ACK, READ or WRITE).
//-----------------------------------------------------------------------------
static void tx_frame(uint32_t frame, uint8_t len) {
// wait for next tx timeslot
last_frame_end += TAG_FRAME_WAIT;
legic_prng_forward(TAG_FRAME_WAIT/TAG_BIT_PERIOD - 1);
while(GetCountSspClk() < last_frame_end) { };
// backup ts for trace log
uint32_t last_frame_start = last_frame_end;
// transmit frame, MSB first
for(uint8_t i = 0; i < len; ++i) {
bool bit = (frame >> i) & 0x01;
tx_bit(bit ^ legic_prng_get_bit());
legic_prng_forward(1);
};
// disable subcarrier
LOW(GPIO_SSC_DOUT);
// log
uint8_t cmdbytes[] = {len, BYTEx(frame, 0), BYTEx(frame, 1)};
LogTrace(cmdbytes, sizeof(cmdbytes), last_frame_start, last_frame_end, NULL, false);
}
static void tx_ack() {
// wait for ack timeslot
last_frame_end += TAG_ACK_WAIT;
legic_prng_forward(TAG_ACK_WAIT/TAG_BIT_PERIOD - 1);
while(GetCountSspClk() < last_frame_end) { };
// backup ts for trace log
uint32_t last_frame_start = last_frame_end;
// transmit ack (ack is not encrypted)
tx_bit(true);
legic_prng_forward(1);
// disable subcarrier
LOW(GPIO_SSC_DOUT);
// log
uint8_t cmdbytes[] = {1, 1};
LogTrace(cmdbytes, sizeof(cmdbytes), last_frame_start, last_frame_end, NULL, false);
}
// Returns a demedulated frame or -1 on code violation
//
// Since TX to RX delay is arbitrary rx_frame has to:
// - detect start of frame (first pause)
// - forward prng based on ts/TAG_BIT_PERIOD
// - receive the frame
// - detect end of frame (last pause)
static int32_t rx_frame(uint8_t *len) {
int32_t frame = 0;
// add 2 SSP clock cycles (1 for tx and 1 for rx pipeline delay)
// those will be substracted at the end of the rx phase
last_frame_end -= 2;
// wait for first pause (start of frame)
for(uint8_t i = 0; true; ++i) {
// increment prng every TAG_BIT_PERIOD
last_frame_end += TAG_BIT_PERIOD;
legic_prng_forward(1);
// if start of frame was received exit delay loop
if(wait_for(RWD_PAUSE, last_frame_end)) {
last_frame_end = GetCountSspClk();
break;
}
// check for code violation
if(i > RWD_CMD_TIMEOUT) {
return -1;
}
}
// backup ts for trace log
uint32_t last_frame_start = last_frame_end;
// receive frame
for(*len = 0; true; ++(*len)) {
// receive next bit
LED_B_ON();
int8_t bit = rx_bit();
LED_B_OFF();
// check for code violation and to short / long frame
if((bit < 0) && ((*len < RWD_MIN_FRAME_LEN) || (*len > RWD_MAX_FRAME_LEN))) {
return -1;
}
// check for code violation caused by end of frame
if(bit < 0) {
break;
}
// append bit
frame |= (bit ^ legic_prng_get_bit()) << (*len);
legic_prng_forward(1);
}
// rx_bit sets coordination timestamp to start of pause, append pause duration
// and substract 2 SSP clock cycles (1 for rx and 1 for tx pipeline delay) to
// obtain exact end of frame.
last_frame_end += RWD_TIME_PAUSE - 2;
// log
uint8_t cmdbytes[] = {*len, BYTEx(frame, 0), BYTEx(frame, 1), BYTEx(frame, 2)};
LogTrace(cmdbytes, sizeof(cmdbytes), last_frame_start, last_frame_end, NULL, true);
return frame;
}
//-----------------------------------------------------------------------------
// Legic Simulator
//-----------------------------------------------------------------------------
static int32_t init_card(uint8_t cardtype, legic_card_select_t *p_card) {
p_card->tagtype = cardtype;
switch(p_card->tagtype) {
case 0:
p_card->cmdsize = 6;
p_card->addrsize = 5;
p_card->cardsize = 22;
break;
case 1:
p_card->cmdsize = 9;
p_card->addrsize = 8;
p_card->cardsize = 256;
break;
case 2:
p_card->cmdsize = 11;
p_card->addrsize = 10;
p_card->cardsize = 1024;
break;
default:
p_card->cmdsize = 0;
p_card->addrsize = 0;
p_card->cardsize = 0;
return 2;
}
return 0;
}
static void init_tag() {
// configure FPGA
FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR
| FPGA_HF_SIMULATOR_MODULATE_212K);
SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
// configure SSC with defaults
FpgaSetupSsc();
// first pull output to low to prevent glitches then re-claim GPIO_SSC_DOUT
LOW(GPIO_SSC_DOUT);
AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
// reserve a cardmem, meaning we can use the tracelog function in bigbuff easier.
legic_mem = BigBuf_get_EM_addr();
// start trace
clear_trace();
set_tracing(true);
// init crc calculator
crc_init(&legic_crc, 4, 0x19 >> 1, 0x05, 0);
// start 212kHz timer (running from SSP Clock)
StartCountSspClk();
}
// Setup reader to card connection
//
// The setup consists of a three way handshake:
// - Receive initialisation vector 7 bits
// - Transmit card type 6 bits
// - Receive Acknowledge 6 bits
static int32_t setup_phase(legic_card_select_t *p_card) {
uint8_t len = 0;
// init coordination timestamp
last_frame_end = GetCountSspClk();
// reset prng
legic_prng_init(0);
// wait for iv
int32_t iv = rx_frame(&len);
if((len != 7) || (iv < 0)) {
return -1;
}
// configure prng
legic_prng_init(iv);
// reply with card type
switch(p_card->tagtype) {
case 0:
tx_frame(0x0D, 6);
break;
case 1:
tx_frame(0x1D, 6);
break;
case 2:
tx_frame(0x3D, 6);
break;
}
// wait for ack
int32_t ack = rx_frame(&len);
if((len != 6) || (ack < 0)) {
return -1;
}
// validate data
switch(p_card->tagtype) {
case 0:
if(ack != 0x19) return -1;
break;
case 1:
if(ack != 0x39) return -1;
break;
case 2:
if(ack != 0x39) return -1;
break;
}
// During rx the prng is clocked using the variable reader period.
// Since rx_frame detects end of frame by detecting a code violation,
// the prng is off by one bit period after each rx phase. Hence, tx
// code advances the prng by (TAG_FRAME_WAIT/TAG_BIT_PERIOD - 1).
// This is not possible for back to back rx, so this quirk reduces
// the gap by one period.
last_frame_end += TAG_BIT_PERIOD;
return 0;
}
static uint8_t calc_crc4(uint16_t cmd, uint8_t cmd_sz, uint8_t value) {
crc_clear(&legic_crc);
crc_update(&legic_crc, (value << cmd_sz) | cmd, 8 + cmd_sz);
return crc_finish(&legic_crc);
}
static int32_t connected_phase(legic_card_select_t *p_card) {
uint8_t len = 0;
// wait for command
int32_t cmd = rx_frame(&len);
if(cmd < 0) {
return -1;
}
// check if command is LEGIC_READ
if(len == p_card->cmdsize) {
// prepare data
uint8_t byte = legic_mem[cmd >> 1];
uint8_t crc = calc_crc4(cmd, p_card->cmdsize, byte);
// transmit data
tx_frame((crc << 8) | byte, 12);
return 0;
}
// check if command is LEGIC_WRITE
if(len == p_card->cmdsize + 8 + 4) {
// decode data
uint16_t mask = (1 << p_card->addrsize) - 1;
uint16_t addr = (cmd >> 1) & mask;
uint8_t byte = (cmd >> p_card->cmdsize) & 0xff;
uint8_t crc = (cmd >> (p_card->cmdsize + 8)) & 0xf;
// check received against calculated crc
uint8_t calc_crc = calc_crc4(addr << 1, p_card->cmdsize, byte);
if(calc_crc != crc) {
Dbprintf("!!! crc mismatch: %x != %x !!!", calc_crc, crc);
return -1;
}
// store data
legic_mem[addr] = byte;
// transmit ack
tx_ack();
return 0;
}
return -1;
}
//-----------------------------------------------------------------------------
// Command Line Interface
//
// Only this function is public / called from appmain.c
//-----------------------------------------------------------------------------
void LegicRfSimulate(uint8_t cardtype) {
// configure ARM and FPGA
init_tag();
// verify command line input
if(init_card(cardtype, &card) != 0) {
DbpString("Unknown tagtype.");
goto OUT;
}
LED_A_ON();
DbpString("Starting Legic emulator, press button to end");
while(!BUTTON_PRESS()) {
WDT_HIT();
// wait for carrier, restart after timeout
if(!wait_for(RWD_PULSE, GetCountSspClk() + TAG_BIT_PERIOD)) {
continue;
}
// wait for connection, restart on error
if(setup_phase(&card)) {
continue;
}
// conection is established, process commands until one fails
while(!connected_phase(&card)) {
WDT_HIT();
}
}
OUT:
DbpString("Stopped");
switch_off();
StopTicks();
}

19
armsrc/legicrfsim.h Normal file
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@ -0,0 +1,19 @@
//-----------------------------------------------------------------------------
// (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
// 2018 AntiCat
//
// 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 emulation public interface
//-----------------------------------------------------------------------------
#ifndef __LEGICRFSIM_H
#define __LEGICRFSIM_H
#include "proxmark3.h"
extern void LegicRfSimulate(uint8_t tagtype);
#endif /* __LEGICRFSIM_H */

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@ -46,19 +46,15 @@ int usage_legic_rdmem(void){
int usage_legic_sim(void){
PrintAndLogEx(NORMAL, "Simulates a LEGIC Prime tag. MIM22, MIM256, MIM1024 types can be emulated");
PrintAndLogEx(NORMAL, "Use eload/esave to upload a dump into emulator memory");
PrintAndLogEx(NORMAL, "Usage: hf legic sim [h] <tagtype> <phase> <frame> <reqresp>");
PrintAndLogEx(NORMAL, "Usage: hf legic sim [h] <tagtype>");
PrintAndLogEx(NORMAL, "Options:");
PrintAndLogEx(NORMAL, " h : this help");
PrintAndLogEx(NORMAL, " <tagtype> : 0 = MIM22");
PrintAndLogEx(NORMAL, " : 1 = MIM256 (default)");
PrintAndLogEx(NORMAL, " : 2 = MIM1024");
PrintAndLogEx(NORMAL, " <phase> : phase drift");
PrintAndLogEx(NORMAL, " <frame> : frame drift");
PrintAndLogEx(NORMAL, " <reqresp> : reqresp drift");
PrintAndLogEx(NORMAL, " : 2 = MIM1024");
PrintAndLogEx(NORMAL, "");
PrintAndLogEx(NORMAL, "Examples:");
PrintAndLogEx(NORMAL, " hf legic sim");
PrintAndLogEx(NORMAL, " hf legic sim ");
return 0;
}
int usage_legic_write(void){
@ -504,12 +500,13 @@ int CmdLegicRdmem(const char *Cmd) {
return status;
}
// should say which tagtype
// should load a tag to device mem.
// int phase, int frame, int reqresp
int CmdLegicRfSim(const char *Cmd) {
UsbCommand c = {CMD_SIMULATE_TAG_LEGIC_RF, {6,3,0}};
sscanf(Cmd, " %" SCNi64 " %" SCNi64 " %" SCNi64 , &c.arg[0], &c.arg[1], &c.arg[2]);
char cmdp = param_getchar(Cmd, 0);
if ( cmdp == 'H' || cmdp == 'h' ) return usage_legic_sim();
UsbCommand c = {CMD_SIMULATE_TAG_LEGIC_RF, {1}};
sscanf(Cmd, " %" SCNi64, &c.arg[0]);
clearCommandBuffer();
SendCommand(&c);
return 0;

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@ -521,7 +521,8 @@ int CmdTraceList(const char *Cmd) {
if ( protocol == ICLASS )
PrintAndLogEx(NORMAL, "iClass - Timings are not as accurate");
if ( protocol == LEGIC )
PrintAndLogEx(NORMAL, "LEGIC - Timings are in ticks (1us == 1.5ticks)");
PrintAndLogEx(NORMAL, "LEGIC - Reader Mode: Timings are in ticks (1us == 1.5ticks)\n"
" Tag Mode: Timings are in sub carrier periods (1/212 kHz == 4.7us)");
if ( protocol == ISO_15693 )
PrintAndLogEx(NORMAL, "ISO15693 - Timings are not as accurate");
if ( protocol == FELICA )

Binary file not shown.

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@ -51,38 +51,29 @@ begin
end
// Divide 13.56 MHz by 32 to produce the SSP_CLK
// The register is bigger to allow higher division factors of up to /128
// Divide 13.56 MHz to produce various frequencies for SSP_CLK
// and modulation. 11 bits allow for factors of up to /128.
reg [10:0] ssp_clk_divider;
always @(posedge adc_clk)
ssp_clk_divider <= (ssp_clk_divider + 1);
reg ssp_clk;
reg ssp_frame;
always @(negedge adc_clk)
begin
//If we're in 101, we only need a new bit every 8th carrier bit (53Hz). Otherwise, get next bit at 424Khz
if(mod_type == 3'b101)
begin
if(ssp_clk_divider[7:0] == 8'b00000000)
ssp_clk <= 1'b0;
if(ssp_clk_divider[7:0] == 8'b10000000)
ssp_clk <= 1'b1;
end
// Get bit every at 53KHz (every 8th carrier bit of 424kHz)
ssp_clk <= ssp_clk_divider[7];
else if(mod_type == 3'b010)
// Get next bit at 212kHz
ssp_clk <= ssp_clk_divider[5];
else
begin
if(ssp_clk_divider[4:0] == 5'd0)//[4:0] == 5'b00000)
ssp_clk <= 1'b1;
if(ssp_clk_divider[4:0] == 5'd16) //[4:0] == 5'b10000)
ssp_clk <= 1'b0;
end
// Get next bit at 424Khz
ssp_clk <= ssp_clk_divider[4];
end
//assign ssp_clk = ssp_clk_divider[4];
// Divide SSP_CLK by 8 to produce the byte framing signal; the phase of
// this is arbitrary, because it's just a bitstream.
// One nasty issue, though: I can't make it work with both rx and tx at
@ -96,19 +87,19 @@ always @(negedge ssp_clk)
ssp_frame_divider_from_arm <= (ssp_frame_divider_from_arm + 1);
reg ssp_frame;
always @(ssp_frame_divider_to_arm or ssp_frame_divider_from_arm or mod_type)
if(mod_type == 3'b000) // not modulating, so listening, to ARM
ssp_frame = (ssp_frame_divider_to_arm == 3'b000);
else
ssp_frame = (ssp_frame_divider_from_arm == 3'b000);
ssp_frame = (ssp_frame_divider_from_arm == 3'b000);
// Synchronize up the after-hysteresis signal, to produce DIN.
reg ssp_din;
always @(posedge ssp_clk)
ssp_din = after_hysteresis;
// Modulating carrier frequency is fc/16, reuse ssp_clk divider for that
// Modulating carrier frequency is fc/64 (212kHz) to fc/16 (848kHz). Reuse ssp_clk divider for that.
reg modulating_carrier;
always @(mod_type or ssp_clk or ssp_dout)
if(mod_type == 3'b000)
@ -116,9 +107,9 @@ always @(mod_type or ssp_clk or ssp_dout)
else if(mod_type == 3'b001)
modulating_carrier <= ssp_dout ^ ssp_clk_divider[3]; // XOR means BPSK
else if(mod_type == 3'b010)
modulating_carrier <= ssp_dout & ssp_clk_divider[5]; // switch 212kHz subcarrier on/off
modulating_carrier <= ssp_dout & ssp_clk_divider[5]; // switch 212kHz subcarrier on/off
else if(mod_type == 3'b100 || mod_type == 3'b101)
modulating_carrier <= ssp_dout & ssp_clk_divider[4]; // switch 424kHz modulation on/off
modulating_carrier <= ssp_dout & ssp_clk_divider[4]; // switch 424kHz modulation on/off
else
modulating_carrier <= 1'b0; // yet unused
@ -133,9 +124,6 @@ assign pwr_oe4 = modulating_carrier;
// This one is always on, so that we can watch the carrier.
assign pwr_oe3 = 1'b0;
assign dbg = modulating_carrier;
//reg dbg;
//always @(ssp_dout)
// dbg <= ssp_dout;
assign dbg = ssp_din;
endmodule