X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/9e8255d4e99eb2917df13be92402e75a73417696..refs/pull/181/head:/armsrc/iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 54c1db40..27574dad 100644
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -20,7 +20,7 @@
 #include "iso14443a.h"
 #include "crapto1.h"
 #include "mifareutil.h"
-
+#include "BigBuf.h"
 static uint32_t iso14a_timeout;
 int rsamples = 0;
 uint8_t trigger = 0;
@@ -141,6 +141,7 @@ const uint8_t OddByteParity[256] = {
   1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1
 };
 
+
 void iso14a_set_trigger(bool enable) {
 	trigger = enable;
 }
@@ -148,8 +149,32 @@ void iso14a_set_trigger(bool enable) {
 
 void iso14a_set_timeout(uint32_t timeout) {
 	iso14a_timeout = timeout;
+	if(MF_DBGLEVEL >= 3) Dbprintf("ISO14443A Timeout set to %ld (%dms)", iso14a_timeout, iso14a_timeout / 106);
+}
+
+
+void iso14a_set_ATS_timeout(uint8_t *ats) {
+
+	uint8_t tb1;
+	uint8_t fwi; 
+	uint32_t fwt;
+	
+	if (ats[0] > 1) {							// there is a format byte T0
+		if ((ats[1] & 0x20) == 0x20) {			// there is an interface byte TB(1)
+			if ((ats[1] & 0x10) == 0x10) {		// there is an interface byte TA(1) preceding TB(1)
+				tb1 = ats[3];
+			} else {
+				tb1 = ats[2];
+			}
+			fwi = (tb1 & 0xf0) >> 4;			// frame waiting indicator (FWI)
+			fwt = 256 * 16 * (1 << fwi);		// frame waiting time (FWT) in 1/fc
+			
+			iso14a_set_timeout(fwt/(8*16));
+		}
+	}
 }
 
+
 //-----------------------------------------------------------------------------
 // Generate the parity value for a byte sequence
 //
@@ -188,6 +213,11 @@ void AppendCrc14443a(uint8_t* data, int len)
 	ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
 }
 
+void AppendCrc14443b(uint8_t* data, int len)
+{
+	ComputeCrc14443(CRC_14443_B,data,len,data+len,data+len+1);
+}
+
 
 //=============================================================================
 // ISO 14443 Type A - Miller decoder
@@ -208,13 +238,17 @@ void AppendCrc14443a(uint8_t* data, int len)
 static tUart Uart;
 
 // Lookup-Table to decide if 4 raw bits are a modulation.
-// We accept two or three consecutive "0" in any position with the rest "1"
+// We accept the following:
+// 0001  -   a 3 tick wide pause
+// 0011  -   a 2 tick wide pause, or a three tick wide pause shifted left
+// 0111  -   a 2 tick wide pause shifted left
+// 1001  -   a 2 tick wide pause shifted right
 const bool Mod_Miller_LUT[] = {
-	TRUE,  TRUE,  FALSE, TRUE,  FALSE, FALSE, FALSE, FALSE,
-	TRUE,  TRUE,  FALSE, FALSE, TRUE,  FALSE, FALSE, FALSE
+	FALSE,  TRUE, FALSE, TRUE,  FALSE, FALSE, FALSE, TRUE,
+	FALSE,  TRUE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE
 };
-#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x00F0) >> 4])
-#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x000F)])
+#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x000000F0) >> 4])
+#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x0000000F)])
 
 void UartReset()
 {
@@ -224,8 +258,6 @@ void UartReset()
 	Uart.parityLen = 0;					// number of decoded parity bytes
 	Uart.shiftReg = 0;					// shiftreg to hold decoded data bits
 	Uart.parityBits = 0;				// holds 8 parity bits
-	Uart.twoBits = 0x0000;	 			// buffer for 2 Bits
-	Uart.highCnt = 0;
 	Uart.startTime = 0;
 	Uart.endTime = 0;
 }
@@ -234,6 +266,7 @@ void UartInit(uint8_t *data, uint8_t *parity)
 {
 	Uart.output = data;
 	Uart.parity = parity;
+	Uart.fourBits = 0x00000000;			// clear the buffer for 4 Bits
 	UartReset();
 }
 
@@ -241,45 +274,41 @@ void UartInit(uint8_t *data, uint8_t *parity)
 static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
 {
 
-	Uart.twoBits = (Uart.twoBits << 8) | bit;
+	Uart.fourBits = (Uart.fourBits << 8) | bit;
 	
-	if (Uart.state == STATE_UNSYNCD) {												// not yet synced
+	if (Uart.state == STATE_UNSYNCD) {											// not yet synced
 	
-		if (Uart.highCnt < 7) {													// wait for a stable unmodulated signal
-			if (Uart.twoBits == 0xffff) {
-				Uart.highCnt++;
-			} else {
-				Uart.highCnt = 0;
-			}
-		} else {	
-			Uart.syncBit = 0xFFFF; // not set
-			// look for 00xx1111 (the start bit)
-			if 		((Uart.twoBits & 0x6780) == 0x0780) Uart.syncBit = 7; 
-			else if ((Uart.twoBits & 0x33C0) == 0x03C0) Uart.syncBit = 6;
-			else if ((Uart.twoBits & 0x19E0) == 0x01E0) Uart.syncBit = 5;
-			else if ((Uart.twoBits & 0x0CF0) == 0x00F0) Uart.syncBit = 4;
-			else if ((Uart.twoBits & 0x0678) == 0x0078) Uart.syncBit = 3;
-			else if ((Uart.twoBits & 0x033C) == 0x003C) Uart.syncBit = 2;
-			else if ((Uart.twoBits & 0x019E) == 0x001E) Uart.syncBit = 1;
-			else if ((Uart.twoBits & 0x00CF) == 0x000F) Uart.syncBit = 0;
-			if (Uart.syncBit != 0xFFFF) {
-				Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
-				Uart.startTime -= Uart.syncBit;
-				Uart.endTime = Uart.startTime;
-				Uart.state = STATE_START_OF_COMMUNICATION;
-			}
+		Uart.syncBit = 9999; 													// not set
+		// The start bit is one ore more Sequence Y followed by a Sequence Z (... 11111111 00x11111). We need to distinguish from
+		// Sequence X followed by Sequence Y followed by Sequence Z (111100x1 11111111 00x11111)
+		// we therefore look for a ...xx11111111111100x11111xxxxxx... pattern 
+		// (12 '1's followed by 2 '0's, eventually followed by another '0', followed by 5 '1's)
+		#define ISO14443A_STARTBIT_MASK		0x07FFEF80							// mask is    00000111 11111111 11101111 10000000
+		#define ISO14443A_STARTBIT_PATTERN	0x07FF8F80							// pattern is 00000111 11111111 10001111 10000000
+		if		((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 0)) == ISO14443A_STARTBIT_PATTERN >> 0) Uart.syncBit = 7;
+		else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 1)) == ISO14443A_STARTBIT_PATTERN >> 1) Uart.syncBit = 6;
+		else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 2)) == ISO14443A_STARTBIT_PATTERN >> 2) Uart.syncBit = 5;
+		else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 3)) == ISO14443A_STARTBIT_PATTERN >> 3) Uart.syncBit = 4;
+		else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 4)) == ISO14443A_STARTBIT_PATTERN >> 4) Uart.syncBit = 3;
+		else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 5)) == ISO14443A_STARTBIT_PATTERN >> 5) Uart.syncBit = 2;
+		else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 6)) == ISO14443A_STARTBIT_PATTERN >> 6) Uart.syncBit = 1;
+		else if ((Uart.fourBits & (ISO14443A_STARTBIT_MASK >> 7)) == ISO14443A_STARTBIT_PATTERN >> 7) Uart.syncBit = 0;
+
+		if (Uart.syncBit != 9999) {												// found a sync bit
+			Uart.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
+			Uart.startTime -= Uart.syncBit;
+			Uart.endTime = Uart.startTime;
+			Uart.state = STATE_START_OF_COMMUNICATION;
 		}
 
 	} else {
 
-		if (IsMillerModulationNibble1(Uart.twoBits >> Uart.syncBit)) {			
-			if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) {		// Modulation in both halves - error
+		if (IsMillerModulationNibble1(Uart.fourBits >> Uart.syncBit)) {			
+			if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) {		// Modulation in both halves - error
 				UartReset();
-				Uart.highCnt = 6;
 			} else {															// Modulation in first half = Sequence Z = logic "0"
 				if (Uart.state == STATE_MILLER_X) {								// error - must not follow after X
 					UartReset();
-					Uart.highCnt = 6;
 				} else {
 					Uart.bitCount++;
 					Uart.shiftReg = (Uart.shiftReg >> 1);						// add a 0 to the shiftreg
@@ -299,7 +328,7 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
 				}
 			}
 		} else {
-			if (IsMillerModulationNibble2(Uart.twoBits >> Uart.syncBit)) {		// Modulation second half = Sequence X = logic "1"
+			if (IsMillerModulationNibble2(Uart.fourBits >> Uart.syncBit)) {		// Modulation second half = Sequence X = logic "1"
 				Uart.bitCount++;
 				Uart.shiftReg = (Uart.shiftReg >> 1) | 0x100;					// add a 1 to the shiftreg
 				Uart.state = STATE_MILLER_X;
@@ -334,12 +363,11 @@ static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
 					if (Uart.len) {
 						return TRUE;											// we are finished with decoding the raw data sequence
 					} else {
-						UartReset();					// Nothing receiver - start over
+						UartReset();											// Nothing received - start over
 					}
 				}
 				if (Uart.state == STATE_START_OF_COMMUNICATION) {				// error - must not follow directly after SOC
 					UartReset();
-					Uart.highCnt = 6;
 				} else {														// a logic "0"
 					Uart.bitCount++;
 					Uart.shiftReg = (Uart.shiftReg >> 1);						// add a 0 to the shiftreg
@@ -526,32 +554,28 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	// bit 1 - trigger from first reader 7-bit request
 	
 	LEDsoff();
-	// init trace buffer
-	iso14a_clear_trace();
-	iso14a_set_tracing(TRUE);
 
-	// We won't start recording the frames that we acquire until we trigger;
-	// a good trigger condition to get started is probably when we see a
-	// response from the tag.
-	// triggered == FALSE -- to wait first for card
-	bool triggered = !(param & 0x03); 
-	
+	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
+	// Allocate memory from BigBuf for some buffers
+	// free all previous allocations first
+	BigBuf_free();
+
 	// The command (reader -> tag) that we're receiving.
-	// The length of a received command will in most cases be no more than 18 bytes.
-	// So 32 should be enough!
-	uint8_t *receivedCmd = ((uint8_t *)BigBuf) + RECV_CMD_OFFSET;
-	uint8_t *receivedCmdPar = ((uint8_t *)BigBuf) + RECV_CMD_PAR_OFFSET;
+	uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
+	uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
 	
 	// The response (tag -> reader) that we're receiving.
-	uint8_t *receivedResponse = ((uint8_t *)BigBuf) + RECV_RESP_OFFSET;
-	uint8_t *receivedResponsePar = ((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET;
-	
-	// As we receive stuff, we copy it from receivedCmd or receivedResponse
-	// into trace, along with its length and other annotations.
-	//uint8_t *trace = (uint8_t *)BigBuf;
+	uint8_t *receivedResponse = BigBuf_malloc(MAX_FRAME_SIZE);
+	uint8_t *receivedResponsePar = BigBuf_malloc(MAX_PARITY_SIZE);
 	
 	// The DMA buffer, used to stream samples from the FPGA
-	uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+	uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
+
+	// init trace buffer
+	clear_trace();
+	set_tracing(TRUE);
+
 	uint8_t *data = dmaBuf;
 	uint8_t previous_data = 0;
 	int maxDataLen = 0;
@@ -559,8 +583,6 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	bool TagIsActive = FALSE;
 	bool ReaderIsActive = FALSE;
 	
-	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
 	// Set up the demodulator for tag -> reader responses.
 	DemodInit(receivedResponse, receivedResponsePar);
 	
@@ -570,6 +592,12 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	// Setup and start DMA.
 	FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
 	
+	// We won't start recording the frames that we acquire until we trigger;
+	// a good trigger condition to get started is probably when we see a
+	// response from the tag.
+	// triggered == FALSE -- to wait first for card
+	bool triggered = !(param & 0x03); 
+	
 	// And now we loop, receiving samples.
 	for(uint32_t rsamples = 0; TRUE; ) {
 
@@ -591,7 +619,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 		// test for length of buffer
 		if(dataLen > maxDataLen) {
 			maxDataLen = dataLen;
-			if(dataLen > 400) {
+			if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
 				Dbprintf("blew circular buffer! dataLen=%d", dataLen);
 				break;
 			}
@@ -656,6 +684,9 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 
 					// And ready to receive another response.
 					DemodReset();
+					// And reset the Miller decoder including itS (now outdated) input buffer
+					UartInit(receivedCmd, receivedCmdPar);
+
 					LED_C_OFF();
 				} 
 				TagIsActive = (Demod.state != DEMOD_UNSYNCD);
@@ -674,7 +705,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 
 	FpgaDisableSscDma();
 	Dbprintf("maxDataLen=%d, Uart.state=%x, Uart.len=%d", maxDataLen, Uart.state, Uart.len);
-	Dbprintf("traceLen=%d, Uart.output[0]=%08x", traceLen, (uint32_t)Uart.output[0]);
+	Dbprintf("traceLen=%d, Uart.output[0]=%08x", BigBuf_get_traceLen(), (uint32_t)Uart.output[0]);
 	LEDsoff();
 }
 
@@ -820,7 +851,7 @@ int EmSendCmdPar(uint8_t *resp, uint16_t respLen, uint8_t *par);
 bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint8_t *reader_Parity,
 				 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint8_t *tag_Parity);
 
-static uint8_t* free_buffer_pointer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
+static uint8_t* free_buffer_pointer;
 
 typedef struct {
   uint8_t* response;
@@ -830,10 +861,6 @@ typedef struct {
   uint32_t ProxToAirDuration;
 } tag_response_info_t;
 
-void reset_free_buffer() {
-  free_buffer_pointer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
-}
-
 bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffer_size) {
 	// Example response, answer to MIFARE Classic read block will be 16 bytes + 2 CRC = 18 bytes
 	// This will need the following byte array for a modulation sequence
@@ -845,7 +872,8 @@ bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffe
 	// ----------- +
 	//    166 bytes, since every bit that needs to be send costs us a byte
 	//
-  
+ 
+ 
   // Prepare the tag modulation bits from the message
   CodeIso14443aAsTag(response_info->response,response_info->response_n);
   
@@ -866,15 +894,22 @@ bool prepare_tag_modulation(tag_response_info_t* response_info, size_t max_buffe
   return true;
 }
 
+
+// "precompile" responses. There are 7 predefined responses with a total of 28 bytes data to transmit.
+// Coded responses need one byte per bit to transfer (data, parity, start, stop, correction) 
+// 28 * 8 data bits, 28 * 1 parity bits, 7 start bits, 7 stop bits, 7 correction bits
+// -> need 273 bytes buffer
+#define ALLOCATED_TAG_MODULATION_BUFFER_SIZE 273
+
 bool prepare_allocated_tag_modulation(tag_response_info_t* response_info) {
   // Retrieve and store the current buffer index
   response_info->modulation = free_buffer_pointer;
   
   // Determine the maximum size we can use from our buffer
-  size_t max_buffer_size = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + FREE_BUFFER_SIZE) - free_buffer_pointer;
+  size_t max_buffer_size = ALLOCATED_TAG_MODULATION_BUFFER_SIZE;
   
   // Forward the prepare tag modulation function to the inner function
-  if (prepare_tag_modulation(response_info,max_buffer_size)) {
+  if (prepare_tag_modulation(response_info, max_buffer_size)) {
     // Update the free buffer offset
     free_buffer_pointer += ToSendMax;
     return true;
@@ -889,10 +924,6 @@ bool prepare_allocated_tag_modulation(tag_response_info_t* response_info) {
 //-----------------------------------------------------------------------------
 void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 {
-	// Enable and clear the trace
-	iso14a_clear_trace();
-	iso14a_set_tracing(TRUE);
-
 	uint8_t sak;
 
 	// The first response contains the ATQA (note: bytes are transmitted in reverse order).
@@ -936,10 +967,11 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 	}
 	
 	// The second response contains the (mandatory) first 24 bits of the UID
-	uint8_t response2[5];
+	uint8_t response2[5] = {0x00};
 
 	// Check if the uid uses the (optional) part
-	uint8_t response2a[5];
+	uint8_t response2a[5] = {0x00};
+	
 	if (uid_2nd) {
 		response2[0] = 0x88;
 		num_to_bytes(uid_1st,3,response2+1);
@@ -960,12 +992,12 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 	response2[4] = response2[0] ^ response2[1] ^ response2[2] ^ response2[3];
 
 	// Prepare the mandatory SAK (for 4 and 7 byte UID)
-	uint8_t response3[3];
+	uint8_t response3[3]  = {0x00};
 	response3[0] = sak;
 	ComputeCrc14443(CRC_14443_A, response3, 1, &response3[1], &response3[2]);
 
 	// Prepare the optional second SAK (for 7 byte UID), drop the cascade bit
-	uint8_t response3a[3];
+	uint8_t response3a[3]  = {0x00};
 	response3a[0] = sak & 0xFB;
 	ComputeCrc14443(CRC_14443_A, response3a, 1, &response3a[1], &response3a[2]);
 
@@ -1001,9 +1033,20 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 		.modulation_n = 0
 	};
   
-	// Reset the offset pointer of the free buffer
-	reset_free_buffer();
-  
+	// We need to listen to the high-frequency, peak-detected path.
+	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
+	BigBuf_free_keep_EM();
+
+	// allocate buffers:
+	uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
+	uint8_t *receivedCmdPar = BigBuf_malloc(MAX_PARITY_SIZE);
+	free_buffer_pointer = BigBuf_malloc(ALLOCATED_TAG_MODULATION_BUFFER_SIZE);
+
+	// clear trace
+	clear_trace();
+	set_tracing(TRUE);
+
 	// Prepare the responses of the anticollision phase
 	// there will be not enough time to do this at the moment the reader sends it REQA
 	for (size_t i=0; i<TAG_RESPONSE_COUNT; i++) {
@@ -1021,20 +1064,12 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 	int happened2 = 0;
 	int cmdsRecvd = 0;
 
-	// We need to listen to the high-frequency, peak-detected path.
-	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
-	// buffers used on software Uart:
-	uint8_t *receivedCmd = ((uint8_t *)BigBuf) + RECV_CMD_OFFSET;
-	uint8_t *receivedCmdPar = ((uint8_t *)BigBuf) + RECV_CMD_PAR_OFFSET;
-
 	cmdsRecvd = 0;
 	tag_response_info_t* p_response;
 
 	LED_A_ON();
 	for(;;) {
 		// Clean receive command buffer
-		
 		if(!GetIso14443aCommandFromReader(receivedCmd, receivedCmdPar, &len)) {
 			DbpString("Button press");
 			break;
@@ -1188,6 +1223,7 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 
 	Dbprintf("%x %x %x", happened, happened2, cmdsRecvd);
 	LED_A_OFF();
+	BigBuf_free_keep_EM();
 }
 
 
@@ -1307,7 +1343,7 @@ void CodeIso14443aBitsAsReaderPar(const uint8_t *cmd, uint16_t bits, const uint8
 		}
 
 		// Only transmit parity bit if we transmitted a complete byte
-		if (j == 8) {
+		if (j == 8 && parity != NULL) {
 			// Get the parity bit
 			if (parity[i>>3] & (0x80 >> (i&0x0007))) {
 				// Sequence X
@@ -1352,6 +1388,7 @@ void CodeIso14443aAsReaderPar(const uint8_t *cmd, uint16_t len, const uint8_t *p
   CodeIso14443aBitsAsReaderPar(cmd, len*8, parity);
 }
 
+
 //-----------------------------------------------------------------------------
 // Wait for commands from reader
 // Stop when button is pressed (return 1) or field was gone (return 2)
@@ -1374,9 +1411,9 @@ static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
 	// Set ADC to read field strength
 	AT91C_BASE_ADC->ADC_CR = AT91C_ADC_SWRST;
 	AT91C_BASE_ADC->ADC_MR =
-				ADC_MODE_PRESCALE(32) |
-				ADC_MODE_STARTUP_TIME(16) |
-				ADC_MODE_SAMPLE_HOLD_TIME(8);
+				ADC_MODE_PRESCALE(63) |
+				ADC_MODE_STARTUP_TIME(1) |
+				ADC_MODE_SAMPLE_HOLD_TIME(15);
 	AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF);
 	// start ADC
 	AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
@@ -1386,7 +1423,7 @@ static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
 
 	// Clear RXRDY:
     uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-
+	
 	for(;;) {
 		WDT_HIT();
 
@@ -1398,7 +1435,7 @@ static int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *parity)
 			analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF];
 			AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
 			if (analogCnt >= 32) {
-				if ((33000 * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
+				if ((MAX_ADC_HF_VOLTAGE * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
 					vtime = GetTickCount();
 					if (!timer) timer = vtime;
 					// 50ms no field --> card to idle state
@@ -1461,7 +1498,7 @@ static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNe
 	AT91C_BASE_SSC->SSC_THR = SEC_F;
 
 	// send cycle
-	for(; i <= respLen; ) {
+	for(; i < respLen; ) {
 		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
 			AT91C_BASE_SSC->SSC_THR = resp[i++];
 			FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
@@ -1473,14 +1510,15 @@ static int EmSendCmd14443aRaw(uint8_t *resp, uint16_t respLen, bool correctionNe
 	}
 
 	// Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
-	for (i = 0; i < 2 ; ) {
+	uint8_t fpga_queued_bits = FpgaSendQueueDelay >> 3;
+	for (i = 0; i <= fpga_queued_bits/8 + 1; ) {
 		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
 			AT91C_BASE_SSC->SSC_THR = SEC_F;
 			FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 			i++;
 		}
 	}
-	
+
 	LastTimeProxToAirStart = ThisTransferTime + (correctionNeeded?8:0);
 
 	return 0;
@@ -1582,7 +1620,7 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receive
 
 	// clear RXRDY:
     uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-	
+
 	c = 0;
 	for(;;) {
 		WDT_HIT();
@@ -1592,13 +1630,14 @@ static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint8_t *receive
 			if(ManchesterDecoding(b, offset, 0)) {
 				NextTransferTime = MAX(NextTransferTime, Demod.endTime - (DELAY_AIR2ARM_AS_READER + DELAY_ARM2AIR_AS_READER)/16 + FRAME_DELAY_TIME_PICC_TO_PCD);
 				return TRUE;
-			} else if (c++ > iso14a_timeout) {
+			} else if (c++ > iso14a_timeout && Demod.state == DEMOD_UNSYNCD) {
 				return FALSE; 
 			}
 		}
 	}
 }
 
+
 void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t *timing)
 {
 	CodeIso14443aBitsAsReaderPar(frame, bits, par);
@@ -1614,11 +1653,13 @@ void ReaderTransmitBitsPar(uint8_t* frame, uint16_t bits, uint8_t *par, uint32_t
 	}
 }
 
+
 void ReaderTransmitPar(uint8_t* frame, uint16_t len, uint8_t *par, uint32_t *timing)
 {
   ReaderTransmitBitsPar(frame, len*8, par, timing);
 }
 
+
 void ReaderTransmitBits(uint8_t* frame, uint16_t len, uint32_t *timing)
 {
   // Generate parity and redirect
@@ -1627,6 +1668,7 @@ void ReaderTransmitBits(uint8_t* frame, uint16_t len, uint32_t *timing)
   ReaderTransmitBitsPar(frame, len, par, timing);
 }
 
+
 void ReaderTransmit(uint8_t* frame, uint16_t len, uint32_t *timing)
 {
   // Generate parity and redirect
@@ -1661,8 +1703,8 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
 	uint8_t sel_all[]    = { 0x93,0x20 };
 	uint8_t sel_uid[]    = { 0x93,0x70,0x00,0x00,0x00,0x00,0x00,0x00,0x00};
 	uint8_t rats[]       = { 0xE0,0x80,0x00,0x00 }; // FSD=256, FSDI=8, CID=0
-	uint8_t *resp = ((uint8_t *)BigBuf) + RECV_RESP_OFFSET;
-	uint8_t *resp_par = ((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET;
+	uint8_t resp[MAX_FRAME_SIZE]; // theoretically. A usual RATS will be much smaller
+	uint8_t resp_par[MAX_PARITY_SIZE];
 	byte_t uid_resp[4];
 	size_t uid_resp_len;
 
@@ -1687,6 +1729,11 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
 		memset(uid_ptr,0,10);
 	}
 
+	// check for proprietary anticollision:
+	if ((resp[0] & 0x1F) == 0) {
+		return 3;
+	}
+	
 	// OK we will select at least at cascade 1, lets see if first byte of UID was 0x88 in
 	// which case we need to make a cascade 2 request and select - this is a long UID
 	// While the UID is not complete, the 3nd bit (from the right) is set in the SAK.
@@ -1790,6 +1837,10 @@ int iso14443a_select_card(byte_t *uid_ptr, iso14a_card_select_t *p_hi14a_card, u
 
 	// reset the PCB block number
 	iso14_pcb_blocknum = 0;
+
+	// set default timeout based on ATS
+	iso14a_set_ATS_timeout(resp);
+
 	return 1;	
 }
 
@@ -1854,17 +1905,18 @@ void ReaderIso14443a(UsbCommand *c)
 {
 	iso14a_command_t param = c->arg[0];
 	uint8_t *cmd = c->d.asBytes;
-	size_t len = c->arg[1];
-	size_t lenbits = c->arg[2];
+	size_t len = c->arg[1] & 0xffff;
+	size_t lenbits = c->arg[1] >> 16;
+	uint32_t timeout = c->arg[2];
 	uint32_t arg0 = 0;
 	byte_t buf[USB_CMD_DATA_SIZE];
 	uint8_t par[MAX_PARITY_SIZE];
   
 	if(param & ISO14A_CONNECT) {
-		iso14a_clear_trace();
+		clear_trace();
 	}
 
-	iso14a_set_tracing(TRUE);
+	set_tracing(TRUE);
 
 	if(param & ISO14A_REQUEST_TRIGGER) {
 		iso14a_set_trigger(TRUE);
@@ -1880,7 +1932,7 @@ void ReaderIso14443a(UsbCommand *c)
 	}
 
 	if(param & ISO14A_SET_TIMEOUT) {
-		iso14a_set_timeout(c->arg[2]);
+		iso14a_set_timeout(timeout);
 	}
 
 	if(param & ISO14A_APDU) {
@@ -1890,15 +1942,38 @@ void ReaderIso14443a(UsbCommand *c)
 
 	if(param & ISO14A_RAW) {
 		if(param & ISO14A_APPEND_CRC) {
-			AppendCrc14443a(cmd,len);
+			if(param & ISO14A_TOPAZMODE) {
+				AppendCrc14443b(cmd,len);
+			} else {
+				AppendCrc14443a(cmd,len);
+			}
 			len += 2;
 			if (lenbits) lenbits += 16;
 		}
-		if(lenbits>0) {
-			GetParity(cmd, lenbits/8, par);
-			ReaderTransmitBitsPar(cmd, lenbits, par, NULL);
-		} else {
-			ReaderTransmit(cmd,len, NULL);
+		if(lenbits>0) {				// want to send a specific number of bits (e.g. short commands)
+			if(param & ISO14A_TOPAZMODE) {
+				int bits_to_send = lenbits;
+				uint16_t i = 0;
+				ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 7), NULL, NULL);		// first byte is always short (7bits) and no parity
+				bits_to_send -= 7;
+				while (bits_to_send > 0) {
+					ReaderTransmitBitsPar(&cmd[i++], MIN(bits_to_send, 8), NULL, NULL);	// following bytes are 8 bit and no parity
+					bits_to_send -= 8;
+				}
+			} else {
+				GetParity(cmd, lenbits/8, par);
+				ReaderTransmitBitsPar(cmd, lenbits, par, NULL);							// bytes are 8 bit with odd parity
+			}
+		} else {					// want to send complete bytes only
+			if(param & ISO14A_TOPAZMODE) {
+				uint16_t i = 0;
+				ReaderTransmitBitsPar(&cmd[i++], 7, NULL, NULL);						// first byte: 7 bits, no paritiy
+				while (i < len) {
+					ReaderTransmitBitsPar(&cmd[i++], 8, NULL, NULL);					// following bytes: 8 bits, no paritiy
+				}
+			} else {
+				ReaderTransmit(cmd,len, NULL);											// 8 bits, odd parity
+			}
 		}
 		arg0 = ReaderReceive(buf, par);
 		cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
@@ -1934,7 +2009,7 @@ int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
 		nttmp1 = prng_successor(nttmp1, 1);
 		if (nttmp1 == nt2) return i;
 		nttmp2 = prng_successor(nttmp2, 1);
-			if (nttmp2 == nt1) return -i;
+		if (nttmp2 == nt1) return -i;
 		}
 	
 	return(-99999); // either nt1 or nt2 are invalid nonces
@@ -1954,11 +2029,18 @@ void ReaderMifare(bool first_try)
 	uint8_t mf_nr_ar[]   = { 0x00,0x00,0x00,0x00,0x00,0x00,0x00,0x00 };
 	static uint8_t mf_nr_ar3;
 
-	uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + RECV_RESP_OFFSET);
-	uint8_t* receivedAnswerPar = (((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET);
+	uint8_t receivedAnswer[MAX_MIFARE_FRAME_SIZE];
+	uint8_t receivedAnswerPar[MAX_MIFARE_PARITY_SIZE];
 
-	iso14a_clear_trace();
-	iso14a_set_tracing(TRUE);
+	if (first_try) { 
+		iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+	}
+	
+	// free eventually allocated BigBuf memory. We want all for tracing.
+	BigBuf_free();
+	
+	clear_trace();
+	set_tracing(TRUE);
 
 	byte_t nt_diff = 0;
 	uint8_t par[1] = {0};	// maximum 8 Bytes to be sent here, 1 byte parity is therefore enough
@@ -1973,20 +2055,20 @@ void ReaderMifare(bool first_try)
 	byte_t par_list[8] = {0x00};
 	byte_t ks_list[8] = {0x00};
 
+	#define PRNG_SEQUENCE_LENGTH  (1 << 16);
 	static uint32_t sync_time;
-	static uint32_t sync_cycles;
+	static int32_t sync_cycles;
 	int catch_up_cycles = 0;
 	int last_catch_up = 0;
+	uint16_t elapsed_prng_sequences;
 	uint16_t consecutive_resyncs = 0;
 	int isOK = 0;
 
 	if (first_try) { 
 		mf_nr_ar3 = 0;
-		iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
 		sync_time = GetCountSspClk() & 0xfffffff8;
-		sync_cycles = 65536;									// theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the nonces).
+		sync_cycles = PRNG_SEQUENCE_LENGTH;							// theory: Mifare Classic's random generator repeats every 2^16 cycles (and so do the tag nonces).
 		nt_attacked = 0;
-		nt = 0;
 		par[0] = 0;
 	}
 	else {
@@ -2000,33 +2082,84 @@ void ReaderMifare(bool first_try)
 	LED_B_OFF();
 	LED_C_OFF();
 	
-  
+
+	#define MAX_UNEXPECTED_RANDOM	4		// maximum number of unexpected (i.e. real) random numbers when trying to sync. Then give up.
+	#define MAX_SYNC_TRIES			32
+	#define NUM_DEBUG_INFOS			8		// per strategy
+	#define MAX_STRATEGY			3
+	uint16_t unexpected_random = 0;
+	uint16_t sync_tries = 0;
+	int16_t debug_info_nr = -1;
+	uint16_t strategy = 0;
+	int32_t debug_info[MAX_STRATEGY][NUM_DEBUG_INFOS];
+	uint32_t select_time;
+	uint32_t halt_time;
+	
 	for(uint16_t i = 0; TRUE; i++) {
 		
+		LED_C_ON();
 		WDT_HIT();
 
 		// Test if the action was cancelled
 		if(BUTTON_PRESS()) {
+			isOK = -1;
 			break;
 		}
 		
-		LED_C_ON();
+		if (strategy == 2) {
+			// test with additional hlt command
+			halt_time = 0;
+			int len = mifare_sendcmd_short(NULL, false, 0x50, 0x00, receivedAnswer, receivedAnswerPar, &halt_time);
+			if (len && MF_DBGLEVEL >= 3) {
+				Dbprintf("Unexpected response of %d bytes to hlt command (additional debugging).", len);
+			}
+		}
 
+		if (strategy == 3) {
+			// test with FPGA power off/on
+			FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+			SpinDelay(200);
+			iso14443a_setup(FPGA_HF_ISO14443A_READER_MOD);
+			SpinDelay(100);
+		}
+		
 		if(!iso14443a_select_card(uid, NULL, &cuid)) {
 			if (MF_DBGLEVEL >= 1)	Dbprintf("Mifare: Can't select card");
 			continue;
 		}
+		select_time = GetCountSspClk();
 
-		sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
-		catch_up_cycles = 0;
+		elapsed_prng_sequences = 1;
+		if (debug_info_nr == -1) {
+			sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
+			catch_up_cycles = 0;
 
-		// if we missed the sync time already, advance to the next nonce repeat
-		while(GetCountSspClk() > sync_time) {
-			sync_time = (sync_time & 0xfffffff8) + sync_cycles;
-		}
+			// if we missed the sync time already, advance to the next nonce repeat
+			while(GetCountSspClk() > sync_time) {
+				elapsed_prng_sequences++;
+				sync_time = (sync_time & 0xfffffff8) + sync_cycles;
+			}
 
-		// Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
-		ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+			// Transmit MIFARE_CLASSIC_AUTH at synctime. Should result in returning the same tag nonce (== nt_attacked) 
+			ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+		} else {
+			// collect some information on tag nonces for debugging:
+			#define DEBUG_FIXED_SYNC_CYCLES	PRNG_SEQUENCE_LENGTH
+			if (strategy == 0) {
+				// nonce distances at fixed time after card select:
+				sync_time = select_time + DEBUG_FIXED_SYNC_CYCLES;
+			} else if (strategy == 1) {
+				// nonce distances at fixed time between authentications:
+				sync_time = sync_time + DEBUG_FIXED_SYNC_CYCLES;
+			} else if (strategy == 2) {
+				// nonce distances at fixed time after halt:
+				sync_time = halt_time + DEBUG_FIXED_SYNC_CYCLES;
+			} else {
+				// nonce_distances at fixed time after power on
+				sync_time = DEBUG_FIXED_SYNC_CYCLES;
+			}
+			ReaderTransmit(mf_auth, sizeof(mf_auth), &sync_time);
+		}			
 
 		// Receive the (4 Byte) "random" nonce
 		if (!ReaderReceive(receivedAnswer, receivedAnswerPar)) {
@@ -2044,13 +2177,37 @@ void ReaderMifare(bool first_try)
 			int nt_distance = dist_nt(previous_nt, nt);
 			if (nt_distance == 0) {
 				nt_attacked = nt;
-			}
-			else {
-				if (nt_distance == -99999) { // invalid nonce received, try again
-					continue;
+			} else {
+				if (nt_distance == -99999) { // invalid nonce received
+					unexpected_random++;
+					if (unexpected_random > MAX_UNEXPECTED_RANDOM) {
+						isOK = -3;		// Card has an unpredictable PRNG. Give up	
+						break;
+					} else {
+						continue;		// continue trying...
+					}
+				}
+				if (++sync_tries > MAX_SYNC_TRIES) {
+					if (strategy > MAX_STRATEGY || MF_DBGLEVEL < 3) {
+						isOK = -4; 			// Card's PRNG runs at an unexpected frequency or resets unexpectedly
+						break;
+					} else {				// continue for a while, just to collect some debug info
+						debug_info[strategy][debug_info_nr] = nt_distance;
+						debug_info_nr++;
+						if (debug_info_nr == NUM_DEBUG_INFOS) {
+							strategy++;
+							debug_info_nr = 0;
+						}
+						continue;
+					}
+				}
+				sync_cycles = (sync_cycles - nt_distance/elapsed_prng_sequences);
+				if (sync_cycles <= 0) {
+					sync_cycles += PRNG_SEQUENCE_LENGTH;
+				}
+				if (MF_DBGLEVEL >= 3) {
+					Dbprintf("calibrating in cycle %d. nt_distance=%d, elapsed_prng_sequences=%d, new sync_cycles: %d\n", i, nt_distance, elapsed_prng_sequences, sync_cycles);
 				}
-				sync_cycles = (sync_cycles - nt_distance);
-				if (MF_DBGLEVEL >= 3) Dbprintf("calibrating in cycle %d. nt_distance=%d, Sync_cycles: %d\n", i, nt_distance, sync_cycles);
 				continue;
 			}
 		}
@@ -2061,6 +2218,7 @@ void ReaderMifare(bool first_try)
 				catch_up_cycles = 0;
 				continue;
 			}
+			catch_up_cycles /= elapsed_prng_sequences;
 			if (catch_up_cycles == last_catch_up) {
 				consecutive_resyncs++;
 			}
@@ -2074,6 +2232,9 @@ void ReaderMifare(bool first_try)
 			else {	
 				sync_cycles = sync_cycles + catch_up_cycles;
 				if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d for the fourth time consecutively (nt_distance = %d). Adjusting sync_cycles to %d.\n", i, -catch_up_cycles, sync_cycles);
+				last_catch_up = 0;
+				catch_up_cycles = 0;
+				consecutive_resyncs = 0;
 			}
 			continue;
 		}
@@ -2081,12 +2242,10 @@ void ReaderMifare(bool first_try)
 		consecutive_resyncs = 0;
 		
 		// Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
-		if (ReaderReceive(receivedAnswer, receivedAnswerPar))
-		{
+		if (ReaderReceive(receivedAnswer, receivedAnswerPar)) {
 			catch_up_cycles = 8; 	// the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
 	
-			if (nt_diff == 0)
-			{
+			if (nt_diff == 0) {
 				par_low = par[0] & 0xE0; // there is no need to check all parities for other nt_diff. Parity Bits for mf_nr_ar[0..2] won't change
 			}
 
@@ -2109,6 +2268,10 @@ void ReaderMifare(bool first_try)
 			if (nt_diff == 0 && first_try)
 			{
 				par[0]++;
+				if (par[0] == 0x00) {		// tried all 256 possible parities without success. Card doesn't send NACK.
+					isOK = -2;
+					break;
+				}
 			} else {
 				par[0] = ((par[0] & 0x1F) + 1) | par_low;
 			}
@@ -2117,6 +2280,16 @@ void ReaderMifare(bool first_try)
 
 
 	mf_nr_ar[3] &= 0x1F;
+
+	if (isOK == -4) {
+		if (MF_DBGLEVEL >= 3) {
+			for (uint16_t i = 0; i <= MAX_STRATEGY; i++) {
+				for(uint16_t j = 0; j < NUM_DEBUG_INFOS; j++) {
+					Dbprintf("collected debug info[%d][%d] = %d", i, j, debug_info[i][j]);
+				}
+			}
+		}
+	}
 	
 	byte_t buf[28];
 	memcpy(buf + 0,  uid, 4);
@@ -2125,13 +2298,13 @@ void ReaderMifare(bool first_try)
 	memcpy(buf + 16, ks_list, 8);
 	memcpy(buf + 24, mf_nr_ar, 4);
 		
-	cmd_send(CMD_ACK,isOK,0,0,buf,28);
+	cmd_send(CMD_ACK, isOK, 0, 0, buf, 28);
 
 	// Thats it...
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 	LEDsoff();
 
-	iso14a_set_tracing(FALSE);
+	set_tracing(FALSE);
 }
 
 /**
@@ -2166,10 +2339,10 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 	struct Crypto1State *pcs;
 	pcs = &mpcs;
 	uint32_t numReads = 0;//Counts numer of times reader read a block
-	uint8_t* receivedCmd = get_bigbufptr_recvcmdbuf();
-	uint8_t* receivedCmd_par = receivedCmd + MAX_FRAME_SIZE;
-	uint8_t* response = get_bigbufptr_recvrespbuf();
-	uint8_t* response_par = response + MAX_FRAME_SIZE;
+	uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
+	uint8_t receivedCmd_par[MAX_MIFARE_PARITY_SIZE];
+	uint8_t response[MAX_MIFARE_FRAME_SIZE];
+	uint8_t response_par[MAX_MIFARE_PARITY_SIZE];
 	
 	uint8_t rATQA[] = {0x04, 0x00}; // Mifare classic 1k 4BUID
 	uint8_t rUIDBCC1[] = {0xde, 0xad, 0xbe, 0xaf, 0x62};
@@ -2186,10 +2359,6 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 	uint32_t ar_nr_responses[] = {0,0,0,0,0,0,0,0};
 	uint8_t ar_nr_collected = 0;
 
-	// clear trace
-    iso14a_clear_trace();
-	iso14a_set_tracing(TRUE);
-
 	// Authenticate response - nonce
 	uint32_t nonce = bytes_to_num(rAUTH_NT, 4);
 	
@@ -2227,13 +2396,10 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 	if (_7BUID) {
 		rATQA[0] = 0x44;
 		rUIDBCC1[0] = 0x88;
+		rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
 		rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
 	}
 
-	// We need to listen to the high-frequency, peak-detected path.
-	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-
-
 	if (MF_DBGLEVEL >= 1)	{
 		if (!_7BUID) {
 			Dbprintf("4B UID: %02x%02x%02x%02x", 
@@ -2245,15 +2411,24 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 		}
 	}
 
+	// We need to listen to the high-frequency, peak-detected path.
+	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
+
+	// free eventually allocated BigBuf memory but keep Emulator Memory
+	BigBuf_free_keep_EM();
+
+	// clear trace
+	clear_trace();
+	set_tracing(TRUE);
+
+
 	bool finished = FALSE;
 	while (!BUTTON_PRESS() && !finished) {
 		WDT_HIT();
 
 		// find reader field
-		// Vref = 3300mV, and an 10:1 voltage divider on the input
-		// can measure voltages up to 33000 mV
 		if (cardSTATE == MFEMUL_NOFIELD) {
-			vHf = (33000 * AvgAdc(ADC_CHAN_HF)) >> 10;
+			vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
 			if (vHf > MF_MINFIELDV) {
 				cardSTATE_TO_IDLE();
 				LED_A_ON();
@@ -2328,6 +2503,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parity, TRUE);
 					break;
 				}
+
 				uint32_t ar = bytes_to_num(receivedCmd, 4);
 				uint32_t nr = bytes_to_num(&receivedCmd[4], 4);
 
@@ -2434,6 +2610,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 						ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0); 
 						num_to_bytes(ans, 4, rAUTH_AT);
 					}
+
 					EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
 					//Dbprintf("Sending rAUTH %02x%02x%02x%02x", rAUTH_AT[0],rAUTH_AT[1],rAUTH_AT[2],rAUTH_AT[3]);
 					cardSTATE = MFEMUL_AUTH1;
@@ -2466,13 +2643,13 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 						|| receivedCmd[0] == 0xB0) { // transfer
 					if (receivedCmd[1] >= 16 * 4) {
 						EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
-						if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
+						if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on out of range block: %d (0x%02x), nacking",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
 						break;
 					}
 
 					if (receivedCmd[1] / 4 != cardAUTHSC) {
 						EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
-						if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
+						if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate (0x%02x) on block (0x%02x) not authenticated for (0x%02x), nacking",receivedCmd[0],receivedCmd[1],cardAUTHSC);
 						break;
 					}
 				}
@@ -2614,7 +2791,7 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 		if(ar_nr_collected > 1) {
 			Dbprintf("Collected two pairs of AR/NR which can be used to extract keys from reader:");
 			Dbprintf("../tools/mfkey/mfkey32 %08x %08x %08x %08x %08x %08x",
-					 ar_nr_responses[0], // UID
+					ar_nr_responses[0], // UID
 					ar_nr_responses[1], //NT
 					ar_nr_responses[2], //AR1
 					ar_nr_responses[3], //NR1
@@ -2633,7 +2810,8 @@ void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *
 			}
 		}
 	}
-	if (MF_DBGLEVEL >= 1)	Dbprintf("Emulator stopped. Tracing: %d  trace length: %d ",	tracing, traceLen);
+	if (MF_DBGLEVEL >= 1)	Dbprintf("Emulator stopped. Tracing: %d  trace length: %d ",	tracing, BigBuf_get_traceLen());
+	
 }
 
 
@@ -2650,24 +2828,24 @@ void RAMFUNC SniffMifare(uint8_t param) {
 	// C(red) A(yellow) B(green)
 	LEDsoff();
 	// init trace buffer
-	iso14a_clear_trace();
-	iso14a_set_tracing(TRUE);
+	clear_trace();
+	set_tracing(TRUE);
 
 	// The command (reader -> tag) that we're receiving.
 	// The length of a received command will in most cases be no more than 18 bytes.
 	// So 32 should be enough!
-	uint8_t *receivedCmd = (((uint8_t *)BigBuf) + RECV_CMD_OFFSET);
-	uint8_t *receivedCmdPar = ((uint8_t *)BigBuf) + RECV_CMD_PAR_OFFSET;
+	uint8_t receivedCmd[MAX_MIFARE_FRAME_SIZE];
+	uint8_t receivedCmdPar[MAX_MIFARE_PARITY_SIZE];
 	// The response (tag -> reader) that we're receiving.
-	uint8_t *receivedResponse = (((uint8_t *)BigBuf) + RECV_RESP_OFFSET);
-	uint8_t *receivedResponsePar = ((uint8_t *)BigBuf) + RECV_RESP_PAR_OFFSET;
+	uint8_t receivedResponse[MAX_MIFARE_FRAME_SIZE];
+	uint8_t receivedResponsePar[MAX_MIFARE_PARITY_SIZE];
 
-	// As we receive stuff, we copy it from receivedCmd or receivedResponse
-	// into trace, along with its length and other annotations.
-	//uint8_t *trace = (uint8_t *)BigBuf;
-	
-	// The DMA buffer, used to stream samples from the FPGA
-	uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
+
+	// free eventually allocated BigBuf memory
+	BigBuf_free();
+	// allocate the DMA buffer, used to stream samples from the FPGA
+	uint8_t *dmaBuf = BigBuf_malloc(DMA_BUFFER_SIZE);
 	uint8_t *data = dmaBuf;
 	uint8_t previous_data = 0;
 	int maxDataLen = 0;
@@ -2675,8 +2853,6 @@ void RAMFUNC SniffMifare(uint8_t param) {
 	bool ReaderIsActive = FALSE;
 	bool TagIsActive = FALSE;
 
-	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
-
 	// Set up the demodulator for tag -> reader responses.
 	DemodInit(receivedResponse, receivedResponsePar);
 
@@ -2726,7 +2902,7 @@ void RAMFUNC SniffMifare(uint8_t param) {
 		// test for length of buffer
 		if(dataLen > maxDataLen) {					// we are more behind than ever...
 			maxDataLen = dataLen;					
-			if(dataLen > 400) {
+			if(dataLen > (9 * DMA_BUFFER_SIZE / 10)) {
 				Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
 				break;
 			}
@@ -2756,7 +2932,7 @@ void RAMFUNC SniffMifare(uint8_t param) {
 					if (MfSniffLogic(receivedCmd, Uart.len, Uart.parity, Uart.bitCount, TRUE)) break;
 
 					/* And ready to receive another command. */
-					UartReset();
+					UartInit(receivedCmd, receivedCmdPar);
 					
 					/* And also reset the demod code */
 					DemodReset();
@@ -2773,6 +2949,8 @@ void RAMFUNC SniffMifare(uint8_t param) {
 
 					// And ready to receive another response.
 					DemodReset();
+					// And reset the Miller decoder including its (now outdated) input buffer
+					UartInit(receivedCmd, receivedCmdPar);
 				}
 				TagIsActive = (Demod.state != DEMOD_UNSYNCD);
 			}