X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/3e750be37cd8e3231ae02260be6899391d206cb4..d41efbf21b66e47b0ae7b4154bebf77669f4b607:/armsrc/legicrf.c?ds=sidebyside

diff --git a/armsrc/legicrf.c b/armsrc/legicrf.c
index 7a156f69..19f12a95 100644
--- a/armsrc/legicrf.c
+++ b/armsrc/legicrf.c
@@ -1,5 +1,6 @@
 //-----------------------------------------------------------------------------
 // (c) 2009 Henryk Plötz <henryk@ploetzli.ch>
+//     2016 Iceman
 //
 // 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
@@ -10,7 +11,7 @@
 #include "legicrf.h"
 
 static struct legic_frame {
-	int bits;
+	uint8_t bits;
 	uint32_t data;
 } current_frame;
 
@@ -68,15 +69,11 @@ static void setup_timer(void) {
 */
 
 // 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 */
-
 // testing calculating in (us) microseconds.
 #define	RWD_TIME_1 120		// READER_TIME_PAUSE 20us off, 80us on = 100us  80 * 1.5 == 120ticks
 #define RWD_TIME_0 60		// READER_TIME_PAUSE 20us off, 40us on = 60us   40 * 1.5 == 60ticks 
 #define RWD_TIME_PAUSE 30	// 20us == 20 * 1.5 == 30ticks */
-#define TAG_BIT_PERIOD 150	// 100us == 100 * 1.5 == 150ticks
+#define TAG_BIT_PERIOD 142	// 100us == 100 * 1.5 == 150ticks
 #define TAG_FRAME_WAIT 495  // 330us from READER frame end to TAG frame start. 330 * 1.5 == 495
 
 #define RWD_TIME_FUZZ 20   // rather generous 13us, since the peak detector + hysteresis fuzz quite a bit
@@ -89,14 +86,12 @@ static void setup_timer(void) {
 #define FUZZ_EQUAL(value, target, fuzz) ((value) > ((target)-(fuzz)) && (value) < ((target)+(fuzz)))
 
 #ifndef SHORT_COIL
-# define SHORT_COIL	LOW(GPIO_SSC_DOUT);
+# define SHORT_COIL	 LOW(GPIO_SSC_DOUT);
 #endif
 #ifndef OPEN_COIL
 # define OPEN_COIL	HIGH(GPIO_SSC_DOUT);
 #endif
 
-uint32_t sendFrameStop = 0;
-
 // Pause pulse,  off in 20us / 30ticks,
 // ONE / ZERO bit pulse,  
 //    one == 80us / 120ticks
@@ -108,7 +103,7 @@ uint32_t sendFrameStop = 0;
 		WaitTicks( (RWD_TIME_PAUSE) ); \
 		OPEN_COIL; \
 		WaitTicks((x)); \
-	} while (0) 
+	} while (0); 
 #endif
 
 // ToDo: define a meaningful maximum size for auth_table. The bigger this is, the lower will be the available memory for traces. 
@@ -146,14 +141,13 @@ static void frame_clean(struct legic_frame * const f) {
 
 /* Generate Keystream */
 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;
 
 	// reset the prng timer.
-	ResetTimer(prng_timer);
 
 	/* If skip == -1, forward prng time based */
 	if(skip == -1) {
@@ -167,55 +161,41 @@ uint32_t get_key_stream(int skip, int count) {
 
 	i = (count == 6) ? -1 : legic_read_count;
 
-	/* Write Time Data into LOG */
-	// uint8_t *BigBuf = BigBuf_get_addr();
-	// 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;
+	// log
+	//uint8_t cmdbytes[] = {bits,	BYTEx(data, 0), BYTEx(data, 1),	BYTEx(send, 0), BYTEx(send, 1), legic_prng_count()};
+	//LogTrace(cmdbytes, sizeof(cmdbytes), starttime, GET_TICKS, NULL, TRUE);
 
 	/* Generate KeyStream */
-	for(i=0; i<count; i++) {
-		key |= legic_prng_get_bit() << i;
-		legic_prng_forward(1);
-	}
-	return key;
+	return legic_prng_get_bits(count);
 }
 
 /* Send a frame in tag mode, the FPGA must have been set up by
  * LegicRfSimulate
  */
-void frame_send_tag(uint16_t response, uint8_t bits, uint8_t crypt) {
+void frame_send_tag(uint16_t response, uint8_t bits) {
+
+	uint16_t mask = 1;
+	
 	/* Bitbang the response */
-	LOW(GPIO_SSC_DOUT);
+	SHORT_COIL;
 	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_FRAME_WAIT -> shift by 2 */
-		response ^= legic_prng_get_bits(bits);
-	}
+	 /* TAG_FRAME_WAIT -> shift by 2 */
+	legic_prng_forward(2);
+	response ^= legic_prng_get_bits(bits);
 
 	/* Wait for the frame start */
-	WaitUS( TAG_FRAME_WAIT );
-
-	uint8_t bit = 0;
-	for(int i = 0; i < bits; i++) {
-
-		bit = response & 1;
-		response >>= 1;
+	WaitTicks( TAG_FRAME_WAIT );
 
-		if (bit)
-			HIGH(GPIO_SSC_DOUT);
+	for (; mask < BITMASK(bits); mask <<= 1) {	
+		if (response & mask)
+			OPEN_COIL
 		else
-			LOW(GPIO_SSC_DOUT);
-		  
-		WaitUS(100);
+			SHORT_COIL
+		WaitTicks(TAG_BIT_PERIOD);
    }
-   LOW(GPIO_SSC_DOUT);
+   SHORT_COIL;
 }
 
 /* Send a frame in reader mode, the FPGA must have been set up by
@@ -225,33 +205,23 @@ void frame_sendAsReader(uint32_t data, uint8_t bits){
 
 	uint32_t starttime = GET_TICKS, send = 0;
 	uint16_t mask = 1;
-	uint8_t prngstart = legic_prng_count() ;
 	
 	// xor lsfr onto data.
 	send = data ^ legic_prng_get_bits(bits);
 				
 	for (; mask < BITMASK(bits); mask <<= 1) {	
-		if (send & mask) {
-			COIL_PULSE(RWD_TIME_1);
-		} else {
-			COIL_PULSE(RWD_TIME_0);
-		}
+		if (send & mask)
+			COIL_PULSE(RWD_TIME_1)
+		else
+			COIL_PULSE(RWD_TIME_0)
 	}
 
 	// Final pause to mark the end of the frame
 	COIL_PULSE(0);
 	
-	sendFrameStop = GET_TICKS;
-	uint8_t cmdbytes[] = {
-		bits,
-		BYTEx(data, 0), 
-		BYTEx(data, 1),
-		BYTEx(send, 0), 
-		BYTEx(send, 1),
-		prngstart,
-		legic_prng_count()
-	};
-	LogTrace(cmdbytes, sizeof(cmdbytes), starttime, sendFrameStop, NULL, TRUE);
+	// log
+	uint8_t cmdbytes[] = {bits,	BYTEx(data, 0), BYTEx(data, 1),	BYTEx(send, 0), BYTEx(send, 1)};
+	LogTrace(cmdbytes, sizeof(cmdbytes), starttime, GET_TICKS, NULL, TRUE);
 }
 
 /* Receive a frame from the card in reader emulation mode, the FPGA and
@@ -277,48 +247,31 @@ void frame_sendAsReader(uint32_t data, uint8_t bits){
  */
 static void frame_receiveAsReader(struct legic_frame * const f, uint8_t bits) {
 
-	frame_clean(f);
 	if ( bits > 32 ) return;
 	
 	uint8_t i = bits, edges = 0;	
-	uint16_t lsfr = 0;
-	uint32_t the_bit = 1, next_bit_at = 0, data;
-	
-	int old_level = 0, level = 0;
+	uint32_t the_bit = 1, next_bit_at = 0, data = 0;
+	uint32_t old_level = 0;
+	volatile uint32_t level = 0;
 	
+	frame_clean(f);
+		
 	AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_DIN;
 	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DIN;
 	
 	// calibrate the prng.
-	// 
 	legic_prng_forward(2);
-	
-	// precompute the cipher
-	uint8_t prngstart =  legic_prng_count() ;
-
-	data = lsfr = legic_prng_get_bits(bits);
+	data = legic_prng_get_bits(bits);
 	
 	//FIXED time between sending frame and now listening frame. 330us
-	// 387 = 0x19  0001 1001
-	// 480 = 0x19
-	// 500 = 0x1C  0001 1100
 	uint32_t starttime = GET_TICKS;
-	//uint16_t mywait =  TAG_FRAME_WAIT - (starttime - sendFrameStop);
-	//uint16_t mywait =  495 - (starttime - sendFrameStop);
-	if ( bits == 6) {
-		//Dbprintf("6 WAIT %d", 495 - 9 - 9 );
-		WaitTicks( 495 - 9 - 9 );
-	} else {
-		//Dbprintf("x WAIT %d", mywait );
-		//WaitTicks( mywait );
-		WaitTicks( 450 );
-	}
+	// its about 9+9 ticks delay from end-send to here.
+	WaitTicks( 477 );
 
-	next_bit_at =  GET_TICKS + TAG_BIT_PERIOD;
+	next_bit_at = GET_TICKS + TAG_BIT_PERIOD;
 
 	while ( i-- ){
 		edges = 0;
-		uint8_t adjust = 0;
 		while  ( GET_TICKS < next_bit_at) {
 
 			level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
@@ -327,17 +280,11 @@ static void frame_receiveAsReader(struct legic_frame * const f, uint8_t bits) {
 				++edges;
 			
 			old_level = level;
-			
-			if(edges > 20 && adjust == 0) {
-				next_bit_at -= 15;
-				adjust = 1;
-			}
 		}		
 
 		next_bit_at += TAG_BIT_PERIOD;
 		
-		// We expect 42 edges  == ONE
-		//if (edges > 20 && edges < 64)
+		// We expect 42 edges (ONE)
 		if ( edges > 20 )
 			data ^= the_bit;
 
@@ -348,15 +295,8 @@ static void frame_receiveAsReader(struct legic_frame * const f, uint8_t bits) {
 	f->data = data;
 	f->bits = bits;
 	
-	uint8_t cmdbytes[] = {
-		bits,
-		BYTEx(data,0),
-		BYTEx(data,1),
-		BYTEx(data, 0) ^ BYTEx(lsfr,0),
-		BYTEx(data, 1) ^ BYTEx(lsfr,1),
-		prngstart,
-		legic_prng_count()
-	};
+	// log
+	uint8_t cmdbytes[] = {bits,	BYTEx(data, 0),	BYTEx(data, 1)};
 	LogTrace(cmdbytes, sizeof(cmdbytes), starttime, GET_TICKS, NULL, FALSE);
 }
 
@@ -365,7 +305,7 @@ static uint32_t setup_phase_reader(uint8_t iv) {
 	
 	// Switch on carrier and let the tag charge for 1ms
 	HIGH(GPIO_SSC_DOUT);
-	WaitUS(1000);	
+	WaitUS(5000);	
 	
 	ResetTicks();
 	
@@ -380,9 +320,10 @@ static uint32_t setup_phase_reader(uint8_t iv) {
 
 	frame_receiveAsReader(&current_frame, 6);
 
-	// fixed delay before sending ack.
-	WaitTicks(366);  // 244us
-	legic_prng_forward(1);  //240us / 100 == 2.4 iterations
+	// 292us (438t) - fixed delay before sending ack.
+	// minus log and stuff 100tick?
+	WaitTicks(338);
+	legic_prng_forward(3); 
 	
 	// Send obsfuscated acknowledgment frame.
 	// 0x19 = 0x18 MIM22, 0x01 LSB READCMD 
@@ -393,6 +334,8 @@ static uint32_t setup_phase_reader(uint8_t iv) {
 		case 0x3D: frame_sendAsReader(0x39, 6); break;
 		default: break;
 	}
+
+	legic_prng_forward(2);
 	return current_frame.data;
 }
 
@@ -408,7 +351,7 @@ static void LegicCommonInit(void) {
 	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
 
 	// reserve a cardmem,  meaning we can use the tracelog function in bigbuff easier.
-	cardmem = BigBuf_malloc(LEGIC_CARD_MEMSIZE);
+	cardmem = BigBuf_get_EM_addr();
 	memset(cardmem, 0x00, LEGIC_CARD_MEMSIZE);
 
 	clear_trace();
@@ -423,46 +366,39 @@ static void switch_off_tag_rwd(void) {
 	LOW(GPIO_SSC_DOUT);
 	WaitUS(20);
 	WDT_HIT();
-	set_tracing(FALSE);
 }
 
 // calculate crc4 for a legic READ command 
-// 5,8,10 address size.
-static uint32_t legic4Crc(uint8_t legicCmd, uint16_t byte_index, uint8_t value, uint8_t cmd_sz) {
+static uint32_t legic4Crc(uint8_t cmd, uint16_t byte_index, uint8_t value, uint8_t cmd_sz) {
 	crc_clear(&legic_crc);	
-	//uint32_t temp =  (value << cmd_sz) | (byte_index << 1) | legicCmd;
-	//crc_update(&legic_crc, temp, cmd_sz + 8 );
-	crc_update(&legic_crc, 1, 1); /* CMD_READ */
-	crc_update(&legic_crc, byte_index, cmd_sz-1);
-	crc_update(&legic_crc, value, 8);
+	uint32_t temp =  (value << cmd_sz) | (byte_index << 1) | cmd;
+	crc_update(&legic_crc, temp, cmd_sz + 8 );
 	return crc_finish(&legic_crc);
 }
 
-int legic_read_byte(int byte_index, int cmd_sz) {
+int legic_read_byte( uint16_t index, uint8_t cmd_sz) {
 
-	uint8_t byte = 0, crc = 0, calcCrc = 0;
-	uint32_t cmd = (byte_index << 1) | LEGIC_READ;
+	uint8_t byte, crc, calcCrc = 0;
+	uint32_t cmd = (index << 1) | LEGIC_READ;
 	
-	// (us)| ticks
-	// -------------
-	// 330 | 495
-	// 460 | 690
-	// 258 | 387
-	// 244 | 366
-	WaitTicks(387); 
-	legic_prng_forward(4); // 460 / 100 = 4.6  iterations
+	// 90ticks = 60us (should be 100us but crc calc takes time.)
+	//WaitTicks(330); // 330ticks prng(4) - works
+	WaitTicks(240); // 240ticks prng(3) - works
 	
 	frame_sendAsReader(cmd, cmd_sz);
 	frame_receiveAsReader(&current_frame, 12);
 
+	// CRC check. 
 	byte = BYTEx(current_frame.data, 0);
-	calcCrc = legic4Crc(LEGIC_READ, byte_index, byte, cmd_sz);
 	crc = BYTEx(current_frame.data, 1);
+	calcCrc = legic4Crc(LEGIC_READ, index, byte, cmd_sz);
 
 	if( calcCrc != crc ) {
 		Dbprintf("!!! crc mismatch: expected %x but got %x !!!",  calcCrc, crc);
 		return -1;
 	}
+
+	legic_prng_forward(3);
 	return byte;
 }
 
@@ -471,58 +407,55 @@ int legic_read_byte(int byte_index, int cmd_sz) {
  * - 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(uint8_t byte, uint16_t addr, uint8_t addr_sz) {
-
-    //do not write UID, CRC at offset 0-4.
-	if (addr <= 4) return 0;
+int legic_write_byte(uint16_t index, uint8_t byte, uint8_t addr_sz) {
 
 	// crc
 	crc_clear(&legic_crc);
 	crc_update(&legic_crc, 0, 1); /* CMD_WRITE */
-	crc_update(&legic_crc, addr, addr_sz);
+	crc_update(&legic_crc, index, addr_sz);
 	crc_update(&legic_crc, byte, 8);
 	uint32_t crc = crc_finish(&legic_crc);
-
-	uint32_t crc2 = legic4Crc(LEGIC_WRITE, addr, byte, addr_sz+1);
-	if ( crc != crc2 ) 
+	uint32_t crc2 = legic4Crc(LEGIC_WRITE, index, byte, addr_sz+1);
+	if ( crc != crc2 ) {
 		Dbprintf("crc is missmatch");
-	
+		return 1;
+	}
 	// send write command
 	uint32_t cmd = ((crc     <<(addr_sz+1+8)) //CRC
                    |(byte    <<(addr_sz+1))   //Data
-                   |(addr    <<1)             //Address
-                   | LEGIC_WRITE);             //CMD = Write
+                   |(index    <<1)             //index
+                   | LEGIC_WRITE);            //CMD = Write
 				   
     uint32_t cmd_sz = addr_sz+1+8+4;          //crc+data+cmd
 
-    legic_prng_forward(2); /* we wait anyways */
+    legic_prng_forward(2);
 	
-	WaitUS(TAG_FRAME_WAIT);
+	WaitTicks(330);
 	
 	frame_sendAsReader(cmd, cmd_sz);
-  
-	// wllm-rbnt doesnt have these
+
+	// wait for ack
 	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;
 
-	WaitUS(TAG_FRAME_WAIT);
+	// ACK 3.6ms = 3600us * 1.5 = 5400ticks.
+	WaitTicks(5360);
 
     for( t = 0; t < 80; ++t) {
         edges = 0;
 		next_bit_at += TAG_BIT_PERIOD;
         while(timer->TC_CV < next_bit_at) {
-            int level = (AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_DIN);
+            volatile uint32_t 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 */
+		/* expected are 42 edges (ONE) */
+        if(edges > 20 ) {
 			int t = timer->TC_CV;
 			int c = t / TAG_BIT_PERIOD;
 			
@@ -532,63 +465,39 @@ int legic_write_byte(uint8_t byte, uint16_t addr, uint8_t addr_sz) {
         }
     }
 
-	ResetTimer(timer);
 	return -1;
 }
 
-int LegicRfReader(int offset, int bytes, int iv) {
+int LegicRfReader(uint16_t offset, uint16_t len, uint8_t iv) {
 	
-	uint16_t byte_index = 0;
-	uint8_t cmd_sz = 0, isOK = 1;
-	int card_sz = 0;
-
-	LegicCommonInit();
-
-	uint32_t tag_type = setup_phase_reader(iv);
+	uint16_t i = 0;
+	uint8_t isOK = 1;
+	legic_card_select_t card;
 	
-	switch_off_tag_rwd();
+	LegicCommonInit();
 	
-	switch(tag_type) {
-		case 0x0d:
-			if ( MF_DBGLEVEL >= 2) DbpString("MIM22 card found, reading card");
-            cmd_sz = 6;
-			card_sz = 22;
-			break;
-		case 0x1d:
-			if ( MF_DBGLEVEL >= 2) DbpString("MIM256 card found, reading card");
-            cmd_sz = 9;
-			card_sz = 256;
-			break;
-		case 0x3d:
-			if ( MF_DBGLEVEL >= 2) DbpString("MIM1024 card found, reading card");
-            cmd_sz = 11;
-			card_sz = 1024;
-			break;
-		default:
-			if ( MF_DBGLEVEL >= 1) Dbprintf("Unknown card format: %x", tag_type);
-			isOK = 0;
-			goto OUT;
-			break;
+	if ( legic_select_card_iv(&card, iv) ) {
+		isOK = 0;
+		goto OUT;
 	}
-	if (bytes == -1)
-		bytes = card_sz;
 
-	if (bytes + offset >= card_sz)
-		bytes = card_sz - offset;
+	switch_off_tag_rwd();
+
+	if (len + offset >= card.cardsize)
+		len = card.cardsize - offset;
 
-	// Start setup and read bytes.
 	setup_phase_reader(iv);
-	
+		
 	LED_B_ON();
-	while (byte_index < bytes) {
-		int r = legic_read_byte(byte_index + offset, cmd_sz);
+	while (i < len) {
+		int r = legic_read_byte(offset + i, card.cmdsize);
 		
 		if (r == -1 || BUTTON_PRESS()) {			
-	        if ( MF_DBGLEVEL >= 3) DbpString("operation aborted");
+	        if ( MF_DBGLEVEL >= 2) DbpString("operation aborted");
 			isOK = 0;
 			goto OUT;
 		}
-		cardmem[++byte_index] = r;
+		cardmem[i++] = r;
         WDT_HIT();
 	}
 
@@ -596,229 +505,175 @@ OUT:
 	WDT_HIT();
 	switch_off_tag_rwd();
 	LEDsoff();
-	uint8_t len = (bytes & 0x3FF);
-	cmd_send(CMD_ACK,isOK,len,0,cardmem,len);
+	cmd_send(CMD_ACK, isOK, len, 0, cardmem, len);
     return 0;
 }
 
-/*int _LegicRfWriter(int offset, int bytes, int addr_sz, uint8_t *BigBuf, int RoundBruteforceValue) {
-	int byte_index=0;
-
-    LED_B_ON();
-	setup_phase_reader(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 offset, int bytes, int iv) {
+void LegicRfWriter(uint16_t offset, uint16_t len, uint8_t iv, uint8_t *data) {
 
-	int byte_index = 0, addr_sz = 0;								  
-
-	LegicCommonInit();
+	uint8_t isOK = 1;
 	
-	if ( MF_DBGLEVEL >= 2) 	DbpString("setting up legic card");
+	// UID not is writeable.
+	if ( offset <= 4 ) {
+		isOK = 0;
+		goto OUT;
+	}
 	
-	uint32_t tag_type = setup_phase_reader(iv);
+	legic_card_select_t card;
 	
-	switch_off_tag_rwd();
+	LegicCommonInit();
 	
-	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;
-			if ( MF_DBGLEVEL >= 2) 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;
-			if ( MF_DBGLEVEL >= 2) 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;
-			if ( MF_DBGLEVEL >= 2) 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 ( legic_select_card_iv(&card, iv) ) {
+		isOK = 0;
+		goto OUT;
 	}
+	
+	if (len + offset >= card.cardsize)
+		len = card.cardsize - offset;
 
-    LED_B_ON();
 	setup_phase_reader(iv);
-	int r = 0;
-	while(byte_index < bytes) {
-
-		//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(cardmem[(0x06-byte_index)], (0x06-byte_index), addr_sz);
 
-			// write second byte on success...
-			if(r == 0) {
-				byte_index++;
-				r = legic_write_byte(cardmem[(0x06-byte_index)], (0x06-byte_index), addr_sz);
-			}
-		}
-		else {
-			r = legic_write_byte(cardmem[byte_index+offset], byte_index+offset, addr_sz);
-		}
+    LED_B_ON();	
+	int r = 0;
+	// how about we write backwards instead. no need for this extra DCF check.	
+	// index = len - cardsize
+	// stops uid 01234, 
+	/*
+	len = 20
+	offset = 5
+	
+	index = 20+5 = 25
+	if ( index > cardsize ) return -1;
+	
+	loop
+		write( cardmem[index], index , card.addrsize);
+		--index;
+	end loop	
+	*/
+	uint16_t index = len;
+	while(index > 4) {
+
+		r = legic_write_byte( index, cardmem[ index ], card.addrsize);
 		
-		if ((r != 0) || BUTTON_PRESS()) {
-			Dbprintf("operation aborted @ 0x%03.3x", byte_index);
-			switch_off_tag_rwd();
-			LEDsoff();
-			return;
+		if ( r ) {
+			Dbprintf("operation aborted @ 0x%03.3x", index);
+			isOK = 0;
+			goto OUT;
 		}
-
-        WDT_HIT();
-		byte_index++;
+		--index;
+		WDT_HIT();
 	}
-	LEDsoff();
-    if ( MF_DBGLEVEL >= 1) DbpString("write successful");
+
+OUT:
+	cmd_send(CMD_ACK, isOK, 0,0,0,0);
+	switch_off_tag_rwd();
+	LEDsoff();	
 }
 
-void LegicRfRawWriter(int address, int byte, int iv) {
+int legic_select_card_iv(legic_card_select_t *p_card, uint8_t iv){
 
-	int byte_index = 0, addr_sz = 0;
-	
-	LegicCommonInit();
-	
-	if ( MF_DBGLEVEL >= 2) DbpString("setting up legic card");
-	
-	uint32_t tag_type = setup_phase_reader(iv);
+	if ( p_card == NULL ) return 1;
 	
-	switch_off_tag_rwd();
+	p_card->tagtype = setup_phase_reader(iv);
 	
-	switch(tag_type) {
+	switch(p_card->tagtype) {
 		case 0x0d:
-			if(address > 22) {
-				Dbprintf("Error: can not write to 0x%03.3x on MIM22", address);
-				return;
-			}
-			addr_sz = 5;
-			if ( MF_DBGLEVEL >= 2) Dbprintf("MIM22 card found, writing at addr 0x%02.2x - value 0x%02.2x ...", address, byte);
+            p_card->cmdsize = 6;
+			p_card->addrsize = 5;
+			p_card->cardsize = 22;
 			break;
 		case 0x1d:
-			if(address > 0x100) {
-				Dbprintf("Error: can not write to 0x%03.3x on MIM256", address);
-				return;
-			}
-			addr_sz = 8;
-			if ( MF_DBGLEVEL >= 2) Dbprintf("MIM256 card found, writing at addr 0x%02.2x - value 0x%02.2x ...", address, byte);
+			p_card->cmdsize = 9;
+			p_card->addrsize = 8;
+			p_card->cardsize = 256;
 			break;
 		case 0x3d:
-			if(address > 0x400) {
-          		Dbprintf("Error: can not write to 0x%03.3x on MIM1024", address);
-           		return;
-          	}
-			addr_sz = 10;
-			if ( MF_DBGLEVEL >= 2) Dbprintf("MIM1024 card found, writing at addr 0x%03.3x - value 0x%03.3x ...", address, byte);
+            p_card->cmdsize = 11;
+			p_card->addrsize = 10;
+			p_card->cardsize = 1024;
 			break;
-		default:
-			Dbprintf("No or unknown card found, aborting");
-            return;
-	}
-	
-	Dbprintf("integer value: %d address: %d  addr_sz: %d", byte, address, addr_sz);
-    LED_B_ON();
-	
-	setup_phase_reader(iv);
-    		
-	int r = legic_write_byte(byte, address, addr_sz);
-		
-	if((r != 0) || BUTTON_PRESS()) {
-		Dbprintf("operation aborted @ 0x%03.3x (%1d)", byte_index, r);
-		switch_off_tag_rwd();
-		LEDsoff();
-		return;
+		default: 
+		    p_card->cmdsize = 0;
+			p_card->addrsize = 0;
+			p_card->cardsize = 0;
+			return 2;
 	}
+	return 0;
+}
+int legic_select_card(legic_card_select_t *p_card){
+	return legic_select_card_iv(p_card, 0x01);
+}
 
-    LEDsoff();
-    if ( MF_DBGLEVEL >= 1) DbpString("write successful");
+//-----------------------------------------------------------------------------
+// Work with emulator memory
+// 
+// Note: we call FpgaDownloadAndGo(FPGA_BITSTREAM_HF) here although FPGA is not
+// involved in dealing with emulator memory. But if it is called later, it might
+// destroy the Emulator Memory.
+//-----------------------------------------------------------------------------
+// arg0 = offset
+// arg1 = num of bytes
+void LegicEMemSet(uint32_t arg0, uint32_t arg1, uint8_t *data) {
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	legic_emlset_mem(data, arg0, arg1);
+}
+// arg0 = offset
+// arg1 = num of bytes
+void LegicEMemGet(uint32_t arg0, uint32_t arg1) {
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	uint8_t buf[USB_CMD_DATA_SIZE] = {0x00};
+	legic_emlget_mem(buf, arg0, arg1);
+	LED_B_ON();
+	cmd_send(CMD_ACK, arg0, arg1, 0, buf, USB_CMD_DATA_SIZE);
+	LED_B_OFF();
+}
+void legic_emlset_mem(uint8_t *data, int offset, int numofbytes) {
+	cardmem = BigBuf_get_EM_addr();
+	memcpy(cardmem + offset, data, numofbytes);
+}
+void legic_emlget_mem(uint8_t *data, int offset, int numofbytes) {
+	cardmem = BigBuf_get_EM_addr();
+	memcpy(data, cardmem + offset, numofbytes);
 }
 
 void LegicRfInfo(void){
 
-	LegicCommonInit();
-	uint32_t tag_type = setup_phase_reader(0x55);
-	uint8_t cmd_sz = 0;
-	uint16_t card_sz = 0;
+	int r;
 	
-	switch(tag_type) {
-		case 0x0d:
-            cmd_sz = 6;
-			card_sz = 22;
-			break;
-		case 0x1d:
-			cmd_sz = 9;
-			card_sz = 256;
-			break;
-		case 0x3d:
-            cmd_sz = 11;
-			card_sz = 1024;
-			break;
-		default: 
-			cmd_send(CMD_ACK,0,0,0,0,0);
-			goto OUT;
+	uint8_t buf[sizeof(legic_card_select_t)] = {0x00};
+	legic_card_select_t *card = (legic_card_select_t*) buf;
+	
+	LegicCommonInit();
+
+	if ( legic_select_card(card) ) {
+		cmd_send(CMD_ACK,0,0,0,0,0);
+		goto OUT;
 	}
 
-	// read UID bytes.
-	uint8_t uid[] = {0,0,0,0};
-	for ( uint8_t i = 0; i < sizeof(uid); ++i) {
-		int r = legic_read_byte(i, cmd_sz);
+	// read UID bytes
+	for ( uint8_t i = 0; i < sizeof(card->uid); ++i) {
+		r = legic_read_byte(i, card->cmdsize);
 		if ( r == -1 ) {
 			cmd_send(CMD_ACK,0,0,0,0,0);
 			goto OUT;
 		}
-		uid[i] = r & 0xFF;
+		card->uid[i] = r & 0xFF;
+	}
+
+	// MCC byte.
+	r = legic_read_byte(4, card->cmdsize);
+	uint32_t calc_mcc =  CRC8Legic(card->uid, 4);;
+	if ( r != calc_mcc) {
+		cmd_send(CMD_ACK,0,0,0,0,0);
+		goto OUT;
 	}
+	
+	// OK
+	cmd_send(CMD_ACK, 1, 0, 0, buf, sizeof(legic_card_select_t));
 
-	cmd_send(CMD_ACK,1,card_sz,0,uid,sizeof(uid));
-out:	
+OUT:
 	switch_off_tag_rwd();
 	LEDsoff();
-
 }
 
 /* Handle (whether to respond) a frame in tag mode
@@ -828,26 +683,26 @@ 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) {
+	/* First Part of Handshake (IV) */
+	if(f->bits == 7) {
+
+		LED_C_ON();
 
-        LED_C_ON();
-        
 		// Reset prng timer
 		ResetTimer(prng_timer);
-		
-        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;
- 
- 
+
+		legic_prng_init(f->data);
+		frame_send_tag(0x3d, 6); /* 0x3d^0x26 = 0x1B */
+		legic_state = STATE_IV;
+		legic_read_count = 0;
+		legic_prng_bc = 0;
+		legic_prng_iv = f->data;
+
+
 		ResetTimer(timer);
 		WaitUS(280);
-        return;
-   }
+		return;
+	}
 
    /* 0x19==??? */
    if(legic_state == STATE_IV) {
@@ -881,7 +736,7 @@ static void frame_handle_tag(struct legic_frame const * const f)
          //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);
+         frame_send_tag(hash | data, 12);
 
 		 ResetTimer(timer);
          legic_prng_forward(2);
@@ -1127,6 +982,7 @@ void LegicRfSimulate(int phase, int frame, int reqresp)
 // The software UART that receives commands from the reader, and its state
 // variables.
 //-----------------------------------------------------------------------------
+/*
 static struct {
 	enum {
 		STATE_UNSYNCD,
@@ -1141,7 +997,7 @@ static struct {
 	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).
@@ -1266,7 +1122,7 @@ static struct {
 
 	// return FALSE;
 // }
-
+/*
 
 static void UartReset() {
 	Uart.byteCntMax = 3;
@@ -1276,7 +1132,7 @@ static void UartReset() {
 	Uart.posCnt = 0;
 	memset(Uart.output, 0x00, 3);
 }
-
+*/
 // static void UartInit(uint8_t *data) {
 	// Uart.output = data;
 	// UartReset();
@@ -1288,7 +1144,7 @@ static void UartReset() {
 // tag's response, which we leave in the buffer to be demodulated on the
 // PC side.
 //=============================================================================
-
+/*
 static struct {
 	enum {
 		DEMOD_UNSYNCD,
@@ -1307,7 +1163,7 @@ static struct {
 	int     sumI;
 	int     sumQ;
 } Demod;
-
+*/
 /*
  * Handles reception of a bit from the tag
  *
@@ -1322,32 +1178,8 @@ static struct {
  *          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;
@@ -1502,7 +1334,8 @@ static RAMFUNC int HandleLegicSamplesDemod(int ci, int cq)
 	}
 	return FALSE;
 }
-
+*/
+/*
 // Clear out the state of the "UART" that receives from the tag.
 static void DemodReset() {
 	Demod.len = 0;
@@ -1520,13 +1353,17 @@ 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)
+
+ static void GetSamplesForLegicDemod(int n, bool quiet)
 {
 	int max = 0;
 	bool gotFrame = FALSE;
@@ -1601,9 +1438,13 @@ static void GetSamplesForLegicDemod(int n, bool quiet)
 		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;
@@ -1650,12 +1491,13 @@ static void TransmitForLegic(void)
 	}
 	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;
@@ -1687,11 +1529,12 @@ static void CodeLegicBitsAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
 	// 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)
+/*
+  static void CodeAndTransmitLegicAsReader(const uint8_t *cmd, uint8_t cmdlen, int bits)
 {
 	CodeLegicBitsAsReader(cmd, cmdlen, bits);
 	TransmitForLegic();
@@ -1701,8 +1544,9 @@ static void CodeAndTransmitLegicAsReader(const uint8_t *cmd, uint8_t cmdlen, int
 	}
 }
 
-
+*/
 // Set up LEGIC communication
+/*
 void ice_legic_setup() {
 
 	// standard things.
@@ -1731,4 +1575,5 @@ void ice_legic_setup() {
 
 	// initalize prng
 	legic_prng_init(0);
-}
\ No newline at end of file
+}
+*/
\ No newline at end of file