Add basic LEGIC RF communication in tag simulation mode

armsrc/Makefile

@@ -19,6 +19,7 @@ THUMBSRC = start.c \
 	lfops.c \
 	util.c \
 	hitag2.c \
+	legicrf.c \
 	usb.c
 
 # These are to be compiled in ARM mode

armsrc/appmain.c

@@ -8,6 +8,7 @@
 #include <proxmark3.h>
 #include <stdlib.h>
 #include "apps.h"
+#include "legicrf.h"
 #ifdef WITH_LCD
 #include "fonts.h"
 #include "LCD.h"
@@ -588,6 +589,10 @@ void UsbPacketReceived(BYTE *packet, int len)
 			SimulateIso14443aTag(c->ext1, c->ext2);  // ## Simulate iso14443a tag - pass tag type & UID
 			break;
 
+		case CMD_SIMULATE_TAG_LEGIC_RF:
+			LegicRfSimulate();
+			break;
+
 		case CMD_MEASURE_ANTENNA_TUNING:
 			MeasureAntennaTuning();
 			break;

armsrc/legicrf.c

@@ -0,0 +1,172 @@
+/*
+ * LEGIC RF simulation code
+ *  
+ * (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
+ */
+
+#include <proxmark3.h>
+
+#include "apps.h"
+#include "legicrf.h"
+
+static struct legic_frame {
+	int num_bytes;
+	int num_bits;
+	char data[10];
+} current_frame;
+static char response = 0x2b; /* 1101 01 */
+
+static void frame_send(char *response, int num_bytes, int num_bits)
+{
+#if 0
+	/* Use the SSC to send a response. 8-bit transfers, LSBit first, 100us per bit */
+#else 
+	/* 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;
+	
+	/* Wait for the frame start */
+	while(AT91C_BASE_TC1->TC_CV < 490) ;
+	
+	int i;
+	for(i=0; i<(num_bytes*8+num_bits); i++) {
+		int nextbit = AT91C_BASE_TC1->TC_CV + 150;
+		int bit = response[i/8] & (1<<(i%8));
+		if(bit) 
+			AT91C_BASE_PIOA->PIO_SODR = GPIO_SSC_DOUT;
+		else
+			AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
+		while(AT91C_BASE_TC1->TC_CV < nextbit) ;
+	}
+	AT91C_BASE_PIOA->PIO_CODR = GPIO_SSC_DOUT;
+#endif
+}
+
+static void frame_respond(struct legic_frame *f)
+{
+	LED_D_ON();
+	if(f->num_bytes == 0 && f->num_bits == 7) {
+		/* This seems to be the initial dialogue, just send 6 bits of static data */
+		frame_send(&response, 0, 6);
+	}
+	LED_D_OFF();
+}
+
+static void frame_append_bit(struct legic_frame *f, int bit)
+{
+	if(f->num_bytes >= (int)sizeof(f->data))
+		return; /* Overflow, won't happen */
+	f->data[f->num_bytes] |= (bit<<f->num_bits);
+	f->num_bits++;
+	if(f->num_bits > 7) {
+		f->num_bits = 0;
+		f->num_bytes++;
+	}
+}
+
+static int frame_is_empty(struct legic_frame *f)
+{
+	return( (f->num_bytes + f->num_bits) <= 4 );
+}
+
+static void frame_handle(struct legic_frame *f)
+{
+	if( !frame_is_empty(f) ) {
+		frame_respond(f);
+	}
+}
+
+static void frame_clean(struct legic_frame *f)
+{
+	if(!frame_is_empty(f)) 
+		memset(f->data, 0, sizeof(f->data));
+	f->num_bits = 0;
+	f->num_bytes = 0;
+}
+
+static void emit(int bit)
+{
+	if(bit == -1) {
+		frame_handle(&current_frame);
+		frame_clean(&current_frame);
+	} else if(bit == 0) {
+		frame_append_bit(&current_frame, 0);
+	} else if(bit == 1) {
+		frame_append_bit(&current_frame, 1);
+	}
+}
+
+void LegicRfSimulate(void)
+{
+	/* 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.
+	 */
+	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;
+	
+	/* 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);
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+	AT91C_BASE_TC1->TC_CMR = TC_CMR_TCCLKS_TIMER_CLOCK3;
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+	int old_level = 0;
+
+/* At TIMER_CLOCK3 (MCK/32) */
+#define	BIT_TIME_1 150
+#define BIT_TIME_0 90
+#define BIT_TIME_FUZZ 20
+	
+	int active = 0;
+	while(!BUTTON_PRESS()) {
+		int level = !!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
+		int time = AT91C_BASE_TC1->TC_CV;
+		
+		if(level != old_level) {
+			if(level == 1) {
+				AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG;
+				if(time > (BIT_TIME_1-BIT_TIME_FUZZ) && time < (BIT_TIME_1+BIT_TIME_FUZZ)) {
+					/* 1 bit */
+					emit(1);
+					active = 1;
+				} else if(time > (BIT_TIME_0-BIT_TIME_FUZZ) && time < (BIT_TIME_0+BIT_TIME_FUZZ)) {
+					/* 0 bit */
+					emit(0);
+					active = 0;
+				} else {
+					/* invalid */
+					emit(-1);
+					active = 0;
+				}
+			}
+		}
+		
+		if(time >= (BIT_TIME_1+2*BIT_TIME_FUZZ) && active) {
+			/* Frame end */
+			emit(-1);
+			active = 0;
+		}
+		
+		if(time >= (20*BIT_TIME_1) && (AT91C_BASE_TC1->TC_SR & AT91C_TC_CLKSTA)) {
+			AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+		}
+		
+		
+		old_level = level;
+		WDT_HIT();
+	}
+}

armsrc/legicrf.h

@@ -0,0 +1,12 @@
+/*
+ * LEGIC RF emulation public interface
+ * 
+ * (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
+ */
+
+#ifndef LEGICRF_H_
+#define LEGICRF_H_
+
+extern void LegicRfSimulate(void);
+
+#endif /* LEGICRF_H_ */

include/usb_cmd.h

@@ -69,6 +69,7 @@ typedef struct {
 #define CMD_SIMULATE_TAG_ISO_14443a										0x0384
 #define CMD_READER_ISO_14443a													0x0385
 #define CMD_SIMULATE_MIFARE_CARD											0x0386
+#define CMD_SIMULATE_TAG_LEGIC_RF					0x387
 
 // For measurements of the antenna tuning
 #define CMD_MEASURE_ANTENNA_TUNING										0x0400

winsrc/command.cpp

@@ -207,6 +207,13 @@ static void CmdHi14asnoop(char *str)
 	SendCommand(&c, FALSE);
 }
 
+static void CmdLegicRfSim(char *str)
+{
+	UsbCommand c;
+	c.cmd = CMD_SIMULATE_TAG_LEGIC_RF;
+	SendCommand(&c, FALSE);
+}
+
 static void CmdFPGAOff(char *str)		// ## FPGA Control
 {
 	UsbCommand c;
@@ -2900,6 +2907,7 @@ static struct {
 	{"indalademod",		CmdIndalademod,			0, "['224'] -- Demodulate samples for Indala 64 bit UID (option '224' for 224 bit)"},
 	{"lcd",						CmdLcd,							0, "<HEX command> <count> -- Send command/data to LCD"},
 	{"lcdreset",			CmdLcdReset,				0, "Hardware reset LCD"},
+	{"legicrfsim",			CmdLegicRfSim,							0, "Start the LEGIC RF tag simulator"},
 	{"load",					CmdLoad,						1, "<filename> -- Load trace (to graph window"},
 	{"locomread",			CmdLoCommandRead,		0, "<off period> <'0' period> <'1' period> <command> ['h'] -- Modulate LF reader field to send command before read (all periods in microseconds) (option 'h' for 134)"},
 	{"loread",				CmdLoread,					0, "['h'] -- Read 125/134 kHz LF ID-only tag (option 'h' for 134)"},