X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/5cd9ec01e0d6594f7f0f5869f116d8816047d4cb..c936a22f1921f5dd8ebf49a8d1a0fab60337dd31:/armsrc/iso14443a.c

diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index 4bdbb810..d5dd05ca 100644
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -14,6 +14,7 @@
 #include "apps.h"
 #include "util.h"
 #include "string.h"
+#include "cmd.h"
 
 #include "iso14443crc.h"
 #include "iso14443a.h"
@@ -21,11 +22,93 @@
 #include "mifareutil.h"
 
 static uint32_t iso14a_timeout;
-uint8_t *trace = (uint8_t *) BigBuf;
-int traceLen = 0;
+uint8_t *trace = (uint8_t *) BigBuf+TRACE_OFFSET;
 int rsamples = 0;
+int traceLen = 0;
 int tracing = TRUE;
 uint8_t trigger = 0;
+// the block number for the ISO14443-4 PCB
+static uint8_t iso14_pcb_blocknum = 0;
+
+//
+// ISO14443 timing:
+//
+// minimum time between the start bits of consecutive transfers from reader to tag: 7000 carrier (13.56Mhz) cycles
+#define REQUEST_GUARD_TIME (7000/16 + 1)
+// minimum time between last modulation of tag and next start bit from reader to tag: 1172 carrier cycles 
+#define FRAME_DELAY_TIME_PICC_TO_PCD (1172/16 + 1) 
+// bool LastCommandWasRequest = FALSE;
+
+//
+// Total delays including SSC-Transfers between ARM and FPGA. These are in carrier clock cycles (1/13,56MHz)
+//
+// When the PM acts as reader and is receiving tag data, it takes
+// 3 ticks delay in the AD converter
+// 16 ticks until the modulation detector completes and sets curbit
+// 8 ticks until bit_to_arm is assigned from curbit
+// 8*16 ticks for the transfer from FPGA to ARM
+// 4*16 ticks until we measure the time
+// - 8*16 ticks because we measure the time of the previous transfer 
+#define DELAY_AIR2ARM_AS_READER (3 + 16 + 8 + 8*16 + 4*16 - 8*16) 
+
+// When the PM acts as a reader and is sending, it takes
+// 4*16 ticks until we can write data to the sending hold register
+// 8*16 ticks until the SHR is transferred to the Sending Shift Register
+// 8 ticks until the first transfer starts
+// 8 ticks later the FPGA samples the data
+// 1 tick to assign mod_sig_coil
+#define DELAY_ARM2AIR_AS_READER (4*16 + 8*16 + 8 + 8 + 1)
+
+// When the PM acts as tag and is receiving it takes
+// 2 ticks delay in the RF part (for the first falling edge),
+// 3 ticks for the A/D conversion,
+// 8 ticks on average until the start of the SSC transfer,
+// 8 ticks until the SSC samples the first data
+// 7*16 ticks to complete the transfer from FPGA to ARM
+// 8 ticks until the next ssp_clk rising edge
+// 4*16 ticks until we measure the time 
+// - 8*16 ticks because we measure the time of the previous transfer 
+#define DELAY_AIR2ARM_AS_TAG (2 + 3 + 8 + 8 + 7*16 + 8 + 4*16 - 8*16)
+ 
+// The FPGA will report its internal sending delay in
+uint16_t FpgaSendQueueDelay;
+// the 5 first bits are the number of bits buffered in mod_sig_buf
+// the last three bits are the remaining ticks/2 after the mod_sig_buf shift
+#define DELAY_FPGA_QUEUE (FpgaSendQueueDelay<<1)
+
+// When the PM acts as tag and is sending, it takes
+// 4*16 ticks until we can write data to the sending hold register
+// 8*16 ticks until the SHR is transferred to the Sending Shift Register
+// 8 ticks until the first transfer starts
+// 8 ticks later the FPGA samples the data
+// + a varying number of ticks in the FPGA Delay Queue (mod_sig_buf)
+// + 1 tick to assign mod_sig_coil
+#define DELAY_ARM2AIR_AS_TAG (4*16 + 8*16 + 8 + 8 + DELAY_FPGA_QUEUE + 1)
+
+// When the PM acts as sniffer and is receiving tag data, it takes
+// 3 ticks A/D conversion
+// 14 ticks to complete the modulation detection
+// 8 ticks (on average) until the result is stored in to_arm
+// + the delays in transferring data - which is the same for
+// sniffing reader and tag data and therefore not relevant
+#define DELAY_TAG_AIR2ARM_AS_SNIFFER (3 + 14 + 8) 
+ 
+// When the PM acts as sniffer and is receiving reader data, it takes
+// 2 ticks delay in analogue RF receiver (for the falling edge of the 
+// start bit, which marks the start of the communication)
+// 3 ticks A/D conversion
+// 8 ticks on average until the data is stored in to_arm.
+// + the delays in transferring data - which is the same for
+// sniffing reader and tag data and therefore not relevant
+#define DELAY_READER_AIR2ARM_AS_SNIFFER (2 + 3 + 8) 
+
+//variables used for timing purposes:
+//these are in ssp_clk cycles:
+uint32_t NextTransferTime;
+uint32_t LastTimeProxToAirStart;
+uint32_t LastProxToAirDuration;
+
+
 
 // CARD TO READER - manchester
 // Sequence D: 11110000 modulation with subcarrier during first half
@@ -62,500 +145,348 @@ const uint8_t OddByteParity[256] = {
 };
 
 
-void iso14a_set_trigger(int enable) {
+void iso14a_set_trigger(bool enable) {
 	trigger = enable;
 }
 
-void iso14a_clear_tracelen(void) {
+void iso14a_clear_trace() {
+	memset(trace, 0x44, TRACE_SIZE);
 	traceLen = 0;
 }
-void iso14a_set_tracing(int enable) {
+
+void iso14a_set_tracing(bool enable) {
 	tracing = enable;
 }
 
+void iso14a_set_timeout(uint32_t timeout) {
+	iso14a_timeout = timeout;
+}
+
 //-----------------------------------------------------------------------------
 // Generate the parity value for a byte sequence
 //
 //-----------------------------------------------------------------------------
 byte_t oddparity (const byte_t bt)
 {
-  return OddByteParity[bt];
+	return OddByteParity[bt];
 }
 
 uint32_t GetParity(const uint8_t * pbtCmd, int iLen)
 {
-  int i;
-  uint32_t dwPar = 0;
+	int i;
+	uint32_t dwPar = 0;
 
-  // Generate the encrypted data
-  for (i = 0; i < iLen; i++) {
-    // Save the encrypted parity bit
-    dwPar |= ((OddByteParity[pbtCmd[i]]) << i);
-  }
-  return dwPar;
+	// Generate the parity bits
+	for (i = 0; i < iLen; i++) {
+		// and save them to a 32Bit word
+		dwPar |= ((OddByteParity[pbtCmd[i]]) << i);
+	}
+	return dwPar;
 }
 
 void AppendCrc14443a(uint8_t* data, int len)
 {
-  ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
+	ComputeCrc14443(CRC_14443_A,data,len,data+len,data+len+1);
 }
 
 // The function LogTrace() is also used by the iClass implementation in iClass.c
-int RAMFUNC LogTrace(const uint8_t * btBytes, int iLen, int iSamples, uint32_t dwParity, int bReader)
+bool RAMFUNC LogTrace(const uint8_t * btBytes, uint8_t iLen, uint32_t timestamp, uint32_t dwParity, bool readerToTag)
 {
-  // Return when trace is full
-  if (traceLen >= TRACE_SIZE) return FALSE;
-
-  // Trace the random, i'm curious
-  rsamples += iSamples;
-  trace[traceLen++] = ((rsamples >> 0) & 0xff);
-  trace[traceLen++] = ((rsamples >> 8) & 0xff);
-  trace[traceLen++] = ((rsamples >> 16) & 0xff);
-  trace[traceLen++] = ((rsamples >> 24) & 0xff);
-  if (!bReader) {
-    trace[traceLen - 1] |= 0x80;
-  }
-  trace[traceLen++] = ((dwParity >> 0) & 0xff);
-  trace[traceLen++] = ((dwParity >> 8) & 0xff);
-  trace[traceLen++] = ((dwParity >> 16) & 0xff);
-  trace[traceLen++] = ((dwParity >> 24) & 0xff);
-  trace[traceLen++] = iLen;
-  memcpy(trace + traceLen, btBytes, iLen);
-  traceLen += iLen;
-  return TRUE;
+	if (!tracing) return FALSE;
+	// Return when trace is full
+	if (traceLen + sizeof(timestamp) + sizeof(dwParity) + iLen >= TRACE_SIZE) {
+		tracing = FALSE;	// don't trace any more
+		return FALSE;
+	}
+	
+	// Trace the random, i'm curious
+	trace[traceLen++] = ((timestamp >> 0) & 0xff);
+	trace[traceLen++] = ((timestamp >> 8) & 0xff);
+	trace[traceLen++] = ((timestamp >> 16) & 0xff);
+	trace[traceLen++] = ((timestamp >> 24) & 0xff);
+
+	if (!readerToTag) {
+		trace[traceLen - 1] |= 0x80;
+	}
+	trace[traceLen++] = ((dwParity >> 0) & 0xff);
+	trace[traceLen++] = ((dwParity >> 8) & 0xff);
+	trace[traceLen++] = ((dwParity >> 16) & 0xff);
+	trace[traceLen++] = ((dwParity >> 24) & 0xff);
+	trace[traceLen++] = iLen;
+	if (btBytes != NULL && iLen != 0) {
+		memcpy(trace + traceLen, btBytes, iLen);
+	}
+	traceLen += iLen;
+	return TRUE;
 }
 
-//-----------------------------------------------------------------------------
-// The software UART that receives commands from the reader, and its state
-// variables.
+//=============================================================================
+// ISO 14443 Type A - Miller decoder
+//=============================================================================
+// Basics:
+// This decoder is used when the PM3 acts as a tag.
+// The reader will generate "pauses" by temporarily switching of the field. 
+// At the PM3 antenna we will therefore measure a modulated antenna voltage. 
+// The FPGA does a comparison with a threshold and would deliver e.g.:
+// ........  1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1 0 0 1 1 1 1 1 1 1 1 1 1  .......
+// The Miller decoder needs to identify the following sequences:
+// 2 (or 3) ticks pause followed by 6 (or 5) ticks unmodulated: 	pause at beginning - Sequence Z ("start of communication" or a "0")
+// 8 ticks without a modulation: 									no pause - Sequence Y (a "0" or "end of communication" or "no information")
+// 4 ticks unmodulated followed by 2 (or 3) ticks pause:			pause in second half - Sequence X (a "1")
+// Note 1: the bitstream may start at any time. We therefore need to sync.
+// Note 2: the interpretation of Sequence Y and Z depends on the preceding sequence.
 //-----------------------------------------------------------------------------
 static tUart Uart;
 
-static RAMFUNC int MillerDecoding(int bit)
-{
-	//int error = 0;
-	int bitright;
-
-	if(!Uart.bitBuffer) {
-		Uart.bitBuffer = bit ^ 0xFF0;
-		return FALSE;
-	}
-	else {
-		Uart.bitBuffer <<= 4;
-		Uart.bitBuffer ^= bit;
-	}
+// 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"
+const bool Mod_Miller_LUT[] = {
+	TRUE,  TRUE,  FALSE, TRUE,  FALSE, FALSE, FALSE, FALSE,
+	TRUE,  TRUE,  FALSE, FALSE, TRUE,  FALSE, FALSE, FALSE
+};
+#define IsMillerModulationNibble1(b) (Mod_Miller_LUT[(b & 0x00F0) >> 4])
+#define IsMillerModulationNibble2(b) (Mod_Miller_LUT[(b & 0x000F)])
 
-	int EOC = FALSE;
+void UartReset()
+{
+	Uart.state = STATE_UNSYNCD;
+	Uart.bitCount = 0;
+	Uart.len = 0;						// number of decoded data bytes
+	Uart.shiftReg = 0;					// shiftreg to hold decoded data bits
+	Uart.parityBits = 0;				// 
+	Uart.twoBits = 0x0000;	 			// buffer for 2 Bits
+	Uart.highCnt = 0;
+	Uart.startTime = 0;
+	Uart.endTime = 0;
+}
 
-	if(Uart.state != STATE_UNSYNCD) {
-		Uart.posCnt++;
 
-		if((Uart.bitBuffer & Uart.syncBit) ^ Uart.syncBit) {
-			bit = 0x00;
-		}
-		else {
-			bit = 0x01;
-		}
-		if(((Uart.bitBuffer << 1) & Uart.syncBit) ^ Uart.syncBit) {
-			bitright = 0x00;
-		}
-		else {
-			bitright = 0x01;
-		}
-		if(bit != bitright) { bit = bitright; }
+// use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
+static RAMFUNC bool MillerDecoding(uint8_t bit, uint32_t non_real_time)
+{
 
-		if(Uart.posCnt == 1) {
-			// measurement first half bitperiod
-			if(!bit) {
-				Uart.drop = DROP_FIRST_HALF;
-			}
-		}
-		else {
-			// measurement second half bitperiod
-			if(!bit & (Uart.drop == DROP_NONE)) {
-				Uart.drop = DROP_SECOND_HALF;
+	Uart.twoBits = (Uart.twoBits << 8) | bit;
+	
+	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 if(!bit) {
-				// measured a drop in first and second half
-				// which should not be possible
-				Uart.state = STATE_ERROR_WAIT;
-				//error = 0x01;
+		} 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.posCnt = 0;
-
-			switch(Uart.state) {
-				case STATE_START_OF_COMMUNICATION:
-					Uart.shiftReg = 0;
-					if(Uart.drop == DROP_SECOND_HALF) {
-						// error, should not happen in SOC
-						Uart.state = STATE_ERROR_WAIT;
-						//error = 0x02;
-					}
-					else {
-						// correct SOC
-						Uart.state = STATE_MILLER_Z;
-					}
-					break;
-
-				case STATE_MILLER_Z:
-					Uart.bitCnt++;
-					Uart.shiftReg >>= 1;
-					if(Uart.drop == DROP_NONE) {
-						// logic '0' followed by sequence Y
-						// end of communication
-						Uart.state = STATE_UNSYNCD;
-						EOC = TRUE;
-					}
-					// if(Uart.drop == DROP_FIRST_HALF) {
-					// 	Uart.state = STATE_MILLER_Z; stay the same
-					// 	we see a logic '0' }
-					if(Uart.drop == DROP_SECOND_HALF) {
-						// we see a logic '1'
-						Uart.shiftReg |= 0x100;
-						Uart.state = STATE_MILLER_X;
-					}
-					break;
-
-				case STATE_MILLER_X:
-					Uart.shiftReg >>= 1;
-					if(Uart.drop == DROP_NONE) {
-						// sequence Y, we see a '0'
-						Uart.state = STATE_MILLER_Y;
-						Uart.bitCnt++;
-					}
-					if(Uart.drop == DROP_FIRST_HALF) {
-						// Would be STATE_MILLER_Z
-						// but Z does not follow X, so error
-						Uart.state = STATE_ERROR_WAIT;
-						//error = 0x03;
-					}
-					if(Uart.drop == DROP_SECOND_HALF) {
-						// We see a '1' and stay in state X
-						Uart.shiftReg |= 0x100;
-						Uart.bitCnt++;
-					}
-					break;
-
-				case STATE_MILLER_Y:
-					Uart.bitCnt++;
-					Uart.shiftReg >>= 1;
-					if(Uart.drop == DROP_NONE) {
-						// logic '0' followed by sequence Y
-						// end of communication
-						Uart.state = STATE_UNSYNCD;
-						EOC = TRUE;
-					}
-					if(Uart.drop == DROP_FIRST_HALF) {
-						// we see a '0'
-						Uart.state = STATE_MILLER_Z;
-					}
-					if(Uart.drop == DROP_SECOND_HALF) {
-						// We see a '1' and go to state X
-						Uart.shiftReg |= 0x100;
-						Uart.state = STATE_MILLER_X;
-					}
-					break;
+	} else {
 
-				case STATE_ERROR_WAIT:
-					// That went wrong. Now wait for at least two bit periods
-					// and try to sync again
-					if(Uart.drop == DROP_NONE) {
-						Uart.highCnt = 6;
-						Uart.state = STATE_UNSYNCD;
+		if (IsMillerModulationNibble1(Uart.twoBits >> Uart.syncBit)) {			
+			if (IsMillerModulationNibble2(Uart.twoBits >> 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
+					Uart.state = STATE_MILLER_Z;
+					Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 6;
+					if(Uart.bitCount >= 9) {									// if we decoded a full byte (including parity)
+						Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+						Uart.parityBits <<= 1;									// make room for the parity bit
+						Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01);		// store parity bit
+						Uart.bitCount = 0;
+						Uart.shiftReg = 0;
 					}
-					break;
-
-				default:
-					Uart.state = STATE_UNSYNCD;
-					Uart.highCnt = 0;
-					break;
-			}
-
-			Uart.drop = DROP_NONE;
-
-			// should have received at least one whole byte...
-			if((Uart.bitCnt == 2) && EOC && (Uart.byteCnt > 0)) {
-				return TRUE;
+				}
 			}
-
-			if(Uart.bitCnt == 9) {
-				Uart.output[Uart.byteCnt] = (Uart.shiftReg & 0xff);
-				Uart.byteCnt++;
-
-				Uart.parityBits <<= 1;
-				Uart.parityBits ^= ((Uart.shiftReg >> 8) & 0x01);
-
-				if(EOC) {
-					// when End of Communication received and
-					// all data bits processed..
+		} else {
+			if (IsMillerModulationNibble2(Uart.twoBits >> 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;
+				Uart.endTime = Uart.startTime + 8*(9*Uart.len + Uart.bitCount + 1) - 2;
+				if(Uart.bitCount >= 9) {										// if we decoded a full byte (including parity)
+					Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+					Uart.parityBits <<= 1;										// make room for the new parity bit
+					Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); 			// store parity bit
+					Uart.bitCount = 0;
+					Uart.shiftReg = 0;
+				}
+			} else {															// no modulation in both halves - Sequence Y
+				if (Uart.state == STATE_MILLER_Z || Uart.state == STATE_MILLER_Y) {	// Y after logic "0" - End of Communication
+					Uart.state = STATE_UNSYNCD;
+					if(Uart.len == 0 && Uart.bitCount > 0) {										// if we decoded some bits
+						Uart.shiftReg >>= (9 - Uart.bitCount);					// add them to the output
+						Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+						Uart.parityBits <<= 1;									// no parity bit - add "0"
+						Uart.bitCount--;										// last "0" was part of the EOC sequence
+					}
 					return TRUE;
 				}
-				Uart.bitCnt = 0;
-			}
-
-			/*if(error) {
-				Uart.output[Uart.byteCnt] = 0xAA;
-				Uart.byteCnt++;
-				Uart.output[Uart.byteCnt] = error & 0xFF;
-				Uart.byteCnt++;
-				Uart.output[Uart.byteCnt] = 0xAA;
-				Uart.byteCnt++;
-				Uart.output[Uart.byteCnt] = (Uart.bitBuffer >> 8) & 0xFF;
-				Uart.byteCnt++;
-				Uart.output[Uart.byteCnt] = Uart.bitBuffer & 0xFF;
-				Uart.byteCnt++;
-				Uart.output[Uart.byteCnt] = (Uart.syncBit >> 3) & 0xFF;
-				Uart.byteCnt++;
-				Uart.output[Uart.byteCnt] = 0xAA;
-				Uart.byteCnt++;
-				return TRUE;
-			}*/
-		}
-
-	}
-	else {
-		bit = Uart.bitBuffer & 0xf0;
-		bit >>= 4;
-		bit ^= 0x0F;
-		if(bit) {
-			// should have been high or at least (4 * 128) / fc
-			// according to ISO this should be at least (9 * 128 + 20) / fc
-			if(Uart.highCnt == 8) {
-				// we went low, so this could be start of communication
-				// it turns out to be safer to choose a less significant
-				// syncbit... so we check whether the neighbour also represents the drop
-				Uart.posCnt = 1;   // apparently we are busy with our first half bit period
-				Uart.syncBit = bit & 8;
-				Uart.samples = 3;
-				if(!Uart.syncBit)	{ Uart.syncBit = bit & 4; Uart.samples = 2; }
-				else if(bit & 4)	{ Uart.syncBit = bit & 4; Uart.samples = 2; bit <<= 2; }
-				if(!Uart.syncBit)	{ Uart.syncBit = bit & 2; Uart.samples = 1; }
-				else if(bit & 2)	{ Uart.syncBit = bit & 2; Uart.samples = 1; bit <<= 1; }
-				if(!Uart.syncBit)	{ Uart.syncBit = bit & 1; Uart.samples = 0;
-					if(Uart.syncBit && (Uart.bitBuffer & 8)) {
-						Uart.syncBit = 8;
-
-						// the first half bit period is expected in next sample
-						Uart.posCnt = 0;
-						Uart.samples = 3;
+				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
+					Uart.state = STATE_MILLER_Y;
+					if(Uart.bitCount >= 9) {									// if we decoded a full byte (including parity)
+						Uart.output[Uart.len++] = (Uart.shiftReg & 0xff);
+						Uart.parityBits <<= 1;									// make room for the parity bit
+						Uart.parityBits |= ((Uart.shiftReg >> 8) & 0x01); 		// store parity bit
+						Uart.bitCount = 0;
+						Uart.shiftReg = 0;
 					}
 				}
-				else if(bit & 1)	{ Uart.syncBit = bit & 1; Uart.samples = 0; }
-
-				Uart.syncBit <<= 4;
-				Uart.state = STATE_START_OF_COMMUNICATION;
-				Uart.drop = DROP_FIRST_HALF;
-				Uart.bitCnt = 0;
-				Uart.byteCnt = 0;
-				Uart.parityBits = 0;
-				//error = 0;
-			}
-			else {
-				Uart.highCnt = 0;
-			}
-		}
-		else {
-			if(Uart.highCnt < 8) {
-				Uart.highCnt++;
 			}
 		}
-	}
+			
+	} 
 
-    return FALSE;
+    return FALSE;	// not finished yet, need more data
 }
 
+
+
 //=============================================================================
-// ISO 14443 Type A - Manchester
+// ISO 14443 Type A - Manchester decoder
 //=============================================================================
+// Basics:
+// This decoder is used when the PM3 acts as a reader.
+// The tag will modulate the reader field by asserting different loads to it. As a consequence, the voltage
+// at the reader antenna will be modulated as well. The FPGA detects the modulation for us and would deliver e.g. the following:
+// ........ 0 0 1 1 1 1 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 .......
+// The Manchester decoder needs to identify the following sequences:
+// 4 ticks modulated followed by 4 ticks unmodulated: 	Sequence D = 1 (also used as "start of communication")
+// 4 ticks unmodulated followed by 4 ticks modulated: 	Sequence E = 0
+// 8 ticks unmodulated:									Sequence F = end of communication
+// 8 ticks modulated:									A collision. Save the collision position and treat as Sequence D
+// Note 1: the bitstream may start at any time. We therefore need to sync.
+// Note 2: parameter offset is used to determine the position of the parity bits (required for the anticollision command only)
 static tDemod Demod;
 
-static RAMFUNC int ManchesterDecoding(int v)
-{
-	int bit;
-	int modulation;
-	//int error = 0;
-
-	if(!Demod.buff) {
-		Demod.buff = 1;
-		Demod.buffer = v;
-		return FALSE;
-	}
-	else {
-		bit = Demod.buffer;
-		Demod.buffer = v;
-	}
-
-	if(Demod.state==DEMOD_UNSYNCD) {
-		Demod.output[Demod.len] = 0xfa;
-		Demod.syncBit = 0;
-		//Demod.samples = 0;
-		Demod.posCount = 1;		// This is the first half bit period, so after syncing handle the second part
+// Lookup-Table to decide if 4 raw bits are a modulation.
+// We accept three or four "1" in any position
+const bool Mod_Manchester_LUT[] = {
+	FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, FALSE, TRUE,
+	FALSE, FALSE, FALSE, TRUE,  FALSE, TRUE,  TRUE,  TRUE
+};
 
-		if(bit & 0x08) {
-			Demod.syncBit = 0x08;
-		}
+#define IsManchesterModulationNibble1(b) (Mod_Manchester_LUT[(b & 0x00F0) >> 4])
+#define IsManchesterModulationNibble2(b) (Mod_Manchester_LUT[(b & 0x000F)])
 
-		if(bit & 0x04) {
-			if(Demod.syncBit) {
-				bit <<= 4;
-			}
-			Demod.syncBit = 0x04;
-		}
 
-		if(bit & 0x02) {
-			if(Demod.syncBit) {
-				bit <<= 2;
-			}
-			Demod.syncBit = 0x02;
-		}
+void DemodReset()
+{
+	Demod.state = DEMOD_UNSYNCD;
+	Demod.len = 0;						// number of decoded data bytes
+	Demod.shiftReg = 0;					// shiftreg to hold decoded data bits
+	Demod.parityBits = 0;				// 
+	Demod.collisionPos = 0;				// Position of collision bit
+	Demod.twoBits = 0xffff;				// buffer for 2 Bits
+	Demod.highCnt = 0;
+	Demod.startTime = 0;
+	Demod.endTime = 0;
+}
 
-		if(bit & 0x01 && Demod.syncBit) {
-			Demod.syncBit = 0x01;
-		}
-		
-		if(Demod.syncBit) {
-			Demod.len = 0;
-			Demod.state = DEMOD_START_OF_COMMUNICATION;
-			Demod.sub = SUB_FIRST_HALF;
-			Demod.bitCount = 0;
-			Demod.shiftReg = 0;
-			Demod.parityBits = 0;
-			Demod.samples = 0;
-			if(Demod.posCount) {
-				if(trigger) LED_A_OFF();
-				switch(Demod.syncBit) {
-					case 0x08: Demod.samples = 3; break;
-					case 0x04: Demod.samples = 2; break;
-					case 0x02: Demod.samples = 1; break;
-					case 0x01: Demod.samples = 0; break;
-				}
-			}
-			//error = 0;
-		}
-	}
-	else {
-		//modulation = bit & Demod.syncBit;
-		modulation = ((bit << 1) ^ ((Demod.buffer & 0x08) >> 3)) & Demod.syncBit;
+// use parameter non_real_time to provide a timestamp. Set to 0 if the decoder should measure real time
+static RAMFUNC int ManchesterDecoding(uint8_t bit, uint16_t offset, uint32_t non_real_time)
+{
 
-		Demod.samples += 4;
+	Demod.twoBits = (Demod.twoBits << 8) | bit;
+	
+	if (Demod.state == DEMOD_UNSYNCD) {
 
-		if(Demod.posCount==0) {
-			Demod.posCount = 1;
-			if(modulation) {
-				Demod.sub = SUB_FIRST_HALF;
+		if (Demod.highCnt < 2) {											// wait for a stable unmodulated signal
+			if (Demod.twoBits == 0x0000) {
+				Demod.highCnt++;
+			} else {
+				Demod.highCnt = 0;
 			}
-			else {
-				Demod.sub = SUB_NONE;
+		} else {
+			Demod.syncBit = 0xFFFF;			// not set
+			if 		((Demod.twoBits & 0x7700) == 0x7000) Demod.syncBit = 7; 
+			else if ((Demod.twoBits & 0x3B80) == 0x3800) Demod.syncBit = 6;
+			else if ((Demod.twoBits & 0x1DC0) == 0x1C00) Demod.syncBit = 5;
+			else if ((Demod.twoBits & 0x0EE0) == 0x0E00) Demod.syncBit = 4;
+			else if ((Demod.twoBits & 0x0770) == 0x0700) Demod.syncBit = 3;
+			else if ((Demod.twoBits & 0x03B8) == 0x0380) Demod.syncBit = 2;
+			else if ((Demod.twoBits & 0x01DC) == 0x01C0) Demod.syncBit = 1;
+			else if ((Demod.twoBits & 0x00EE) == 0x00E0) Demod.syncBit = 0;
+			if (Demod.syncBit != 0xFFFF) {
+				Demod.startTime = non_real_time?non_real_time:(GetCountSspClk() & 0xfffffff8);
+				Demod.startTime -= Demod.syncBit;
+				Demod.bitCount = offset;			// number of decoded data bits
+				Demod.state = DEMOD_MANCHESTER_DATA;
 			}
 		}
-		else {
-			Demod.posCount = 0;
-			if(modulation && (Demod.sub == SUB_FIRST_HALF)) {
-				if(Demod.state!=DEMOD_ERROR_WAIT) {
-					Demod.state = DEMOD_ERROR_WAIT;
-					Demod.output[Demod.len] = 0xaa;
-					//error = 0x01;
-				}
-			}
-			else if(modulation) {
-				Demod.sub = SUB_SECOND_HALF;
-			}
-
-			switch(Demod.state) {
-				case DEMOD_START_OF_COMMUNICATION:
-					if(Demod.sub == SUB_FIRST_HALF) {
-						Demod.state = DEMOD_MANCHESTER_D;
-					}
-					else {
-						Demod.output[Demod.len] = 0xab;
-						Demod.state = DEMOD_ERROR_WAIT;
-						//error = 0x02;
-					}
-					break;
 
-				case DEMOD_MANCHESTER_D:
-				case DEMOD_MANCHESTER_E:
-					if(Demod.sub == SUB_FIRST_HALF) {
-						Demod.bitCount++;
-						Demod.shiftReg = (Demod.shiftReg >> 1) ^ 0x100;
-						Demod.state = DEMOD_MANCHESTER_D;
-					}
-					else if(Demod.sub == SUB_SECOND_HALF) {
-						Demod.bitCount++;
-						Demod.shiftReg >>= 1;
-						Demod.state = DEMOD_MANCHESTER_E;
-					}
-					else {
-						Demod.state = DEMOD_MANCHESTER_F;
-					}
-					break;
-
-				case DEMOD_MANCHESTER_F:
-					// Tag response does not need to be a complete byte!
-					if(Demod.len > 0 || Demod.bitCount > 0) {
-						if(Demod.bitCount > 0) {
-							Demod.shiftReg >>= (9 - Demod.bitCount);
-							Demod.output[Demod.len] = Demod.shiftReg & 0xff;
-							Demod.len++;
-							// No parity bit, so just shift a 0
-							Demod.parityBits <<= 1;
-						}
-
-						Demod.state = DEMOD_UNSYNCD;
-						return TRUE;
-					}
-					else {
-						Demod.output[Demod.len] = 0xad;
-						Demod.state = DEMOD_ERROR_WAIT;
-						//error = 0x03;
-					}
-					break;
-
-				case DEMOD_ERROR_WAIT:
-					Demod.state = DEMOD_UNSYNCD;
-					break;
-
-				default:
-					Demod.output[Demod.len] = 0xdd;
-					Demod.state = DEMOD_UNSYNCD;
-					break;
-			}
-
-			if(Demod.bitCount>=9) {
-				Demod.output[Demod.len] = Demod.shiftReg & 0xff;
-				Demod.len++;
-
-				Demod.parityBits <<= 1;
-				Demod.parityBits ^= ((Demod.shiftReg >> 8) & 0x01);
+	} else {
 
+		if (IsManchesterModulationNibble1(Demod.twoBits >> Demod.syncBit)) {		// modulation in first half
+			if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) {	// ... and in second half = collision
+				if (!Demod.collisionPos) {
+					Demod.collisionPos = (Demod.len << 3) + Demod.bitCount;
+				}
+			}															// modulation in first half only - Sequence D = 1
+			Demod.bitCount++;
+			Demod.shiftReg = (Demod.shiftReg >> 1) | 0x100;				// in both cases, add a 1 to the shiftreg
+			if(Demod.bitCount == 9) {									// if we decoded a full byte (including parity)
+				Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
+				Demod.parityBits <<= 1;									// make room for the parity bit
+				Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); 	// store parity bit
 				Demod.bitCount = 0;
 				Demod.shiftReg = 0;
 			}
-
-			/*if(error) {
-				Demod.output[Demod.len] = 0xBB;
-				Demod.len++;
-				Demod.output[Demod.len] = error & 0xFF;
-				Demod.len++;
-				Demod.output[Demod.len] = 0xBB;
-				Demod.len++;
-				Demod.output[Demod.len] = bit & 0xFF;
-				Demod.len++;
-				Demod.output[Demod.len] = Demod.buffer & 0xFF;
-				Demod.len++;
-				Demod.output[Demod.len] = Demod.syncBit & 0xFF;
-				Demod.len++;
-				Demod.output[Demod.len] = 0xBB;
-				Demod.len++;
-				return TRUE;
-			}*/
-
+			Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1) - 4;
+		} else {														// no modulation in first half
+			if (IsManchesterModulationNibble2(Demod.twoBits >> Demod.syncBit)) {	// and modulation in second half = Sequence E = 0
+				Demod.bitCount++;
+				Demod.shiftReg = (Demod.shiftReg >> 1);					// add a 0 to the shiftreg
+				if(Demod.bitCount >= 9) {								// if we decoded a full byte (including parity)
+					Demod.output[Demod.len++] = (Demod.shiftReg & 0xff);
+					Demod.parityBits <<= 1;								// make room for the new parity bit
+					Demod.parityBits |= ((Demod.shiftReg >> 8) & 0x01); // store parity bit
+					Demod.bitCount = 0;
+					Demod.shiftReg = 0;
+				}
+				Demod.endTime = Demod.startTime + 8*(9*Demod.len + Demod.bitCount + 1);
+			} else {													// no modulation in both halves - End of communication
+				if (Demod.len > 0 || Demod.bitCount > 0) {				// received something
+					if(Demod.bitCount > 0) {							// if we decoded bits
+						Demod.shiftReg >>= (9 - Demod.bitCount);		// add the remaining decoded bits to the output
+						Demod.output[Demod.len++] = Demod.shiftReg & 0xff;
+						// No parity bit, so just shift a 0
+						Demod.parityBits <<= 1;
+					}
+					return TRUE;										// we are finished with decoding the raw data sequence
+				} else { 												// nothing received. Start over
+					DemodReset();
+				}
+			}
 		}
+			
+	} 
 
-	} // end (state != UNSYNCED)
-
-    return FALSE;
+    return FALSE;	// not finished yet, need more data
 }
 
 //=============================================================================
@@ -575,15 +506,14 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	
 	LEDsoff();
 	// init trace buffer
-	traceLen = 0;
-	memset(trace, 0x44, TRACE_SIZE);
+	iso14a_clear_trace();
 
 	// 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
-	int triggered = !(param & 0x03); 
-
+	bool triggered = !(param & 0x03); 
+	
 	// 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!
@@ -596,40 +526,31 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 	//uint8_t *trace = (uint8_t *)BigBuf;
 	
 	// The DMA buffer, used to stream samples from the FPGA
-	int8_t *dmaBuf = ((int8_t *)BigBuf) + DMA_BUFFER_OFFSET;
-	int8_t *data = dmaBuf;
+	uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+	uint8_t *data = dmaBuf;
+	uint8_t previous_data = 0;
 	int maxDataLen = 0;
 	int dataLen = 0;
+	bool TagIsActive = FALSE;
+	bool ReaderIsActive = FALSE;
+	
+	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
 
 	// Set up the demodulator for tag -> reader responses.
 	Demod.output = receivedResponse;
-	Demod.len = 0;
-	Demod.state = DEMOD_UNSYNCD;
 
 	// Set up the demodulator for the reader -> tag commands
-	memset(&Uart, 0, sizeof(Uart));
 	Uart.output = receivedCmd;
-	Uart.byteCntMax = 32;                        // was 100 (greg)//////////////////
-	Uart.state = STATE_UNSYNCD;
 
-	// Setup for the DMA.
-	FpgaSetupSsc();
+	// Setup and start DMA.
 	FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
-
-	// And put the FPGA in the appropriate mode
-	// Signal field is off with the appropriate LED
-	LED_D_OFF();
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_SNIFFER);
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-
-	// Count of samples received so far, so that we can include timing
-	// information in the trace buffer.
-	rsamples = 0;
+	
 	// And now we loop, receiving samples.
-	while(true) {
+	for(uint32_t rsamples = 0; TRUE; ) {
+
 		if(BUTTON_PRESS()) {
 			DbpString("cancelled by button");
-			goto done;
+			break;
 		}
 
 		LED_A_ON();
@@ -640,14 +561,14 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 		if (readBufDataP <= dmaBufDataP){
 			dataLen = dmaBufDataP - readBufDataP;
 		} else {
-			dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP + 1;
+			dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP;
 		}
 		// test for length of buffer
 		if(dataLen > maxDataLen) {
 			maxDataLen = dataLen;
 			if(dataLen > 400) {
-				Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
-				goto done;
+				Dbprintf("blew circular buffer! dataLen=%d", dataLen);
+				break;
 			}
 		}
 		if(dataLen < 1) continue;
@@ -656,7 +577,7 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 		if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
 			AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
 			AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
-			Dbprintf("RxEmpty ERROR!!! %d", dataLen); // temporary
+			Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
 		}
 		// secondary buffer sets as primary, secondary buffer was stopped
 		if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
@@ -666,50 +587,61 @@ void RAMFUNC SnoopIso14443a(uint8_t param) {
 
 		LED_A_OFF();
 		
-		rsamples += 4;
-		if(MillerDecoding((data[0] & 0xF0) >> 4)) {
-			LED_C_ON();
+		if (rsamples & 0x01) {				// Need two samples to feed Miller and Manchester-Decoder
+
+			if(!TagIsActive) {		// no need to try decoding reader data if the tag is sending
+				uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
+				if (MillerDecoding(readerdata, (rsamples-1)*4)) {
+					LED_C_ON();
 
-			// check - if there is a short 7bit request from reader
-			if ((!triggered) && (param & 0x02) && (Uart.byteCnt == 1) && (Uart.bitCnt = 9)) triggered = TRUE;
+					// check - if there is a short 7bit request from reader
+					if ((!triggered) && (param & 0x02) && (Uart.len == 1) && (Uart.bitCount == 7)) triggered = TRUE;
 
-			if(triggered) {
-				if (!LogTrace(receivedCmd, Uart.byteCnt, 0 - Uart.samples, Uart.parityBits, TRUE)) break;
+					if(triggered) {
+						if (!LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER, Uart.parityBits, TRUE)) break;
+						if (!LogTrace(NULL, 0, Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER, 0, TRUE)) break;
+					}
+					/* And ready to receive another command. */
+					UartReset();
+					/* And also reset the demod code, which might have been */
+					/* false-triggered by the commands from the reader. */
+					DemodReset();
+					LED_B_OFF();
+				}
+				ReaderIsActive = (Uart.state != STATE_UNSYNCD);
 			}
-			/* And ready to receive another command. */
-			Uart.state = STATE_UNSYNCD;
-			/* And also reset the demod code, which might have been */
-			/* false-triggered by the commands from the reader. */
-			Demod.state = DEMOD_UNSYNCD;
-			LED_B_OFF();
-		}
 
-		if(ManchesterDecoding(data[0] & 0x0F)) {
-			LED_B_ON();
+			if(!ReaderIsActive) {		// no need to try decoding tag data if the reader is sending - and we cannot afford the time
+				uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
+				if(ManchesterDecoding(tagdata, 0, (rsamples-1)*4)) {
+					LED_B_ON();
 
-			if (!LogTrace(receivedResponse, Demod.len, 0 - Demod.samples, Demod.parityBits, FALSE)) break;
+					if (!LogTrace(receivedResponse, Demod.len, Demod.startTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER, Demod.parityBits, FALSE)) break;
+					if (!LogTrace(NULL, 0, Demod.endTime*16 - DELAY_TAG_AIR2ARM_AS_SNIFFER, 0, FALSE)) break;
 
-			if ((!triggered) && (param & 0x01)) triggered = TRUE;
+					if ((!triggered) && (param & 0x01)) triggered = TRUE;
 
-			// And ready to receive another response.
-			memset(&Demod, 0, sizeof(Demod));
-			Demod.output = receivedResponse;
-			Demod.state = DEMOD_UNSYNCD;
-			LED_C_OFF();
+					// And ready to receive another response.
+					DemodReset();
+					LED_C_OFF();
+				} 
+				TagIsActive = (Demod.state != DEMOD_UNSYNCD);
+			}
 		}
 
+		previous_data = *data;
+		rsamples++;
 		data++;
-		if(data > dmaBuf + DMA_BUFFER_SIZE) {
+		if(data == dmaBuf + DMA_BUFFER_SIZE) {
 			data = dmaBuf;
 		}
 	} // main cycle
 
 	DbpString("COMMAND FINISHED");
 
-done:
-	AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
-	Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.byteCnt=%x", maxDataLen, Uart.state, Uart.byteCnt);
-	Dbprintf("Uart.byteCntMax=%x, traceLen=%x, Uart.output[0]=%08x", Uart.byteCntMax, traceLen, (int)Uart.output[0]);
+	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]);
 	LEDsoff();
 }
 
@@ -734,6 +666,7 @@ static void CodeIso14443aAsTagPar(const uint8_t *cmd, int len, uint32_t dwParity
 	
 	// Send startbit
 	ToSend[++ToSendMax] = SEC_D;
+	LastProxToAirDuration = 8 * ToSendMax - 4;
 
 	for(i = 0; i < len; i++) {
 		int j;
@@ -752,8 +685,10 @@ static void CodeIso14443aAsTagPar(const uint8_t *cmd, int len, uint32_t dwParity
 		// Get the parity bit
 		if ((dwParity >> i) & 0x01) {
 			ToSend[++ToSendMax] = SEC_D;
+			LastProxToAirDuration = 8 * ToSendMax - 4;
 		} else {
 			ToSend[++ToSendMax] = SEC_E;
+			LastProxToAirDuration = 8 * ToSendMax;
 		}
 	}
 
@@ -768,54 +703,12 @@ static void CodeIso14443aAsTag(const uint8_t *cmd, int len){
 	CodeIso14443aAsTagPar(cmd, len, GetParity(cmd, len));
 }
 
-//-----------------------------------------------------------------------------
-// This is to send a NACK kind of answer, its only 3 bits, I know it should be 4
-//-----------------------------------------------------------------------------
-static void CodeStrangeAnswerAsTag()
-{
-	int i;
-
-    ToSendReset();
-
-	// Correction bit, might be removed when not needed
-	ToSendStuffBit(0);
-	ToSendStuffBit(0);
-	ToSendStuffBit(0);
-	ToSendStuffBit(0);
-	ToSendStuffBit(1);  // 1
-	ToSendStuffBit(0);
-	ToSendStuffBit(0);
-	ToSendStuffBit(0);
-
-	// Send startbit
-	ToSend[++ToSendMax] = SEC_D;
-
-	// 0
-	ToSend[++ToSendMax] = SEC_E;
-
-	// 0
-	ToSend[++ToSendMax] = SEC_E;
-
-	// 1
-	ToSend[++ToSendMax] = SEC_D;
-
-    // Send stopbit
-	ToSend[++ToSendMax] = SEC_F;
-
-	// Flush the buffer in FPGA!!
-	for(i = 0; i < 5; i++) {
-		ToSend[++ToSendMax] = SEC_F;
-	}
-
-    // Convert from last byte pos to length
-    ToSendMax++;
-}
 
 static void Code4bitAnswerAsTag(uint8_t cmd)
 {
 	int i;
 
-    ToSendReset();
+	ToSendReset();
 
 	// Correction bit, might be removed when not needed
 	ToSendStuffBit(0);
@@ -834,8 +727,10 @@ static void Code4bitAnswerAsTag(uint8_t cmd)
 	for(i = 0; i < 4; i++) {
 		if(b & 1) {
 			ToSend[++ToSendMax] = SEC_D;
+			LastProxToAirDuration = 8 * ToSendMax - 4;
 		} else {
 			ToSend[++ToSendMax] = SEC_E;
+			LastProxToAirDuration = 8 * ToSendMax;
 		}
 		b >>= 1;
 	}
@@ -843,13 +738,8 @@ static void Code4bitAnswerAsTag(uint8_t cmd)
 	// Send stopbit
 	ToSend[++ToSendMax] = SEC_F;
 
-	// Flush the buffer in FPGA!!
-	for(i = 0; i < 5; i++) {
-		ToSend[++ToSendMax] = SEC_F;
-	}
-
-    // Convert from last byte pos to length
-    ToSendMax++;
+	// Convert from last byte pos to length
+	ToSendMax++;
 }
 
 //-----------------------------------------------------------------------------
@@ -866,45 +756,111 @@ static int GetIso14443aCommandFromReader(uint8_t *received, int *len, int maxLen
     FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
 
     // Now run a `software UART' on the stream of incoming samples.
+	UartReset();
     Uart.output = received;
-    Uart.byteCntMax = maxLen;
-    Uart.state = STATE_UNSYNCD;
+
+	// clear RXRDY:
+    uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 
     for(;;) {
         WDT_HIT();
 
         if(BUTTON_PRESS()) return FALSE;
-
-        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-            AT91C_BASE_SSC->SSC_THR = 0x00;
-        }
+		
         if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-            uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-			if(MillerDecoding((b & 0xf0) >> 4)) {
-				*len = Uart.byteCnt;
+            b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+			if(MillerDecoding(b, 0)) {
+				*len = Uart.len;
 				return TRUE;
 			}
-			if(MillerDecoding(b & 0x0f)) {
-				*len = Uart.byteCnt;
-				return TRUE;
-			}
-        }
+ 		}
     }
 }
-static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, int correctionNeeded);
+
+static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, bool correctionNeeded);
+int EmSend4bitEx(uint8_t resp, bool correctionNeeded);
+int EmSend4bit(uint8_t resp);
+int EmSendCmdExPar(uint8_t *resp, int respLen, bool correctionNeeded, uint32_t par);
+int EmSendCmdExPar(uint8_t *resp, int respLen, bool correctionNeeded, uint32_t par);
+int EmSendCmdEx(uint8_t *resp, int respLen, bool correctionNeeded);
+int EmSendCmd(uint8_t *resp, int respLen);
+int EmSendCmdPar(uint8_t *resp, int respLen, uint32_t par);
+bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint32_t reader_Parity,
+				 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint32_t tag_Parity);
+
+static uint8_t* free_buffer_pointer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
+
+typedef struct {
+  uint8_t* response;
+  size_t   response_n;
+  uint8_t* modulation;
+  size_t   modulation_n;
+  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
+	//    144        data bits (18 * 8)
+	//     18        parity bits
+	//      2        Start and stop
+	//      1        Correction bit (Answer in 1172 or 1236 periods, see FPGA)
+	//      1        just for the case
+	// ----------- +
+	//    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);
+  
+  // Make sure we do not exceed the free buffer space
+  if (ToSendMax > max_buffer_size) {
+    Dbprintf("Out of memory, when modulating bits for tag answer:");
+    Dbhexdump(response_info->response_n,response_info->response,false);
+    return false;
+  }
+  
+  // Copy the byte array, used for this modulation to the buffer position
+  memcpy(response_info->modulation,ToSend,ToSendMax);
+  
+  // Store the number of bytes that were used for encoding/modulation and the time needed to transfer them
+  response_info->modulation_n = ToSendMax;
+  response_info->ProxToAirDuration = LastProxToAirDuration;
+  
+  return true;
+}
+
+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;
+  
+  // Forward the prepare tag modulation function to the inner function
+  if (prepare_tag_modulation(response_info,max_buffer_size)) {
+    // Update the free buffer offset
+    free_buffer_pointer += ToSendMax;
+    return true;
+  } else {
+    return false;
+  }
+}
 
 //-----------------------------------------------------------------------------
 // Main loop of simulated tag: receive commands from reader, decide what
 // response to send, and send it.
 //-----------------------------------------------------------------------------
-void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
+void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd, byte_t* data)
 {
-  // Enable and clear the trace
-	tracing = TRUE;
-	traceLen = 0;
-  memset(trace, 0x44, TRACE_SIZE);
+	// Enable and clear the trace
+	iso14a_clear_trace();
+	iso14a_set_tracing(TRUE);
 
-	// This function contains the tag emulation
 	uint8_t sak;
 
 	// The first response contains the ATQA (note: bytes are transmitted in reverse order).
@@ -976,60 +932,44 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
 	ComputeCrc14443(CRC_14443_A, response3a, 1, &response3a[1], &response3a[2]);
 
 	uint8_t response5[] = { 0x00, 0x00, 0x00, 0x00 }; // Very random tag nonce
-	uint8_t response6[] = { 0x03, 0x3B, 0x00, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS
-	ComputeCrc14443(CRC_14443_A, response6, 3, &response6[3], &response6[4]);
-
-	uint8_t *resp;
-	int respLen;
-
-  // Longest possible response will be 16 bytes + 2 CRC = 18 bytes
-	// This will need
-	//    144        data bits (18 * 8)
-	//     18        parity bits
-	//      2        Start and stop
-	//      1        Correction bit (Answer in 1172 or 1236 periods, see FPGA)
-	//      1        just for the case
-	// ----------- +
-	//    166
-	//
-	// 166 bytes, since every bit that needs to be send costs us a byte
-	//
-
-	// Respond with card type
-	uint8_t *resp1 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
-	int resp1Len;
-
-	// Anticollision cascade1 - respond with uid
-	uint8_t *resp2 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + 166);
-	int resp2Len;
-
-	// Anticollision cascade2 - respond with 2nd half of uid if asked
-	// we're only going to be asked if we set the 1st byte of the UID (during cascade1) to 0x88
-	uint8_t *resp2a = (((uint8_t *)BigBuf) + 1140);
-	int resp2aLen;
-
-	// Acknowledge select - cascade 1
-	uint8_t *resp3 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*2));
-	int resp3Len;
-
-	// Acknowledge select - cascade 2
-	uint8_t *resp3a = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*3));
-	int resp3aLen;
-
-	// Response to a read request - not implemented atm
-	uint8_t *resp4 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*4));
-	int resp4Len;
-
-	// Authenticate response - nonce
-	uint8_t *resp5 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*5));
-	int resp5Len;
-
-	// Authenticate response - nonce
-	uint8_t *resp6 = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET + (166*6));
-	int resp6Len;
+	uint8_t response6[] = { 0x04, 0x58, 0x00, 0x02, 0x00, 0x00 }; // dummy ATS (pseudo-ATR), answer to RATS
+	ComputeCrc14443(CRC_14443_A, response6, 4, &response6[4], &response6[5]);
+
+	#define TAG_RESPONSE_COUNT 7
+	tag_response_info_t responses[TAG_RESPONSE_COUNT] = {
+		{ .response = response1,  .response_n = sizeof(response1)  },  // Answer to request - respond with card type
+		{ .response = response2,  .response_n = sizeof(response2)  },  // Anticollision cascade1 - respond with uid
+		{ .response = response2a, .response_n = sizeof(response2a) },  // Anticollision cascade2 - respond with 2nd half of uid if asked
+		{ .response = response3,  .response_n = sizeof(response3)  },  // Acknowledge select - cascade 1
+		{ .response = response3a, .response_n = sizeof(response3a) },  // Acknowledge select - cascade 2
+		{ .response = response5,  .response_n = sizeof(response5)  },  // Authentication answer (random nonce)
+		{ .response = response6,  .response_n = sizeof(response6)  },  // dummy ATS (pseudo-ATR), answer to RATS
+	};
+
+	// Allocate 512 bytes for the dynamic modulation, created when the reader queries for it
+	// Such a response is less time critical, so we can prepare them on the fly
+	#define DYNAMIC_RESPONSE_BUFFER_SIZE 64
+	#define DYNAMIC_MODULATION_BUFFER_SIZE 512
+	uint8_t dynamic_response_buffer[DYNAMIC_RESPONSE_BUFFER_SIZE];
+	uint8_t dynamic_modulation_buffer[DYNAMIC_MODULATION_BUFFER_SIZE];
+	tag_response_info_t dynamic_response_info = {
+		.response = dynamic_response_buffer,
+		.response_n = 0,
+		.modulation = dynamic_modulation_buffer,
+		.modulation_n = 0
+	};
+  
+	// Reset the offset pointer of the free buffer
+	reset_free_buffer();
+  
+	// 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++) {
+		prepare_allocated_tag_modulation(&responses[i]);
+	}
 
 	uint8_t *receivedCmd = (((uint8_t *)BigBuf) + RECV_CMD_OFFSET);
-	int len;
+	int len = 0;
 
 	// To control where we are in the protocol
 	int order = 0;
@@ -1038,119 +978,136 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
 	// Just to allow some checks
 	int happened = 0;
 	int happened2 = 0;
-
 	int cmdsRecvd = 0;
-	uint8_t* respdata = NULL;
-	int respsize = 0;
-	uint8_t nack = 0x04;
-
-	memset(receivedCmd, 0x44, RECV_CMD_SIZE);
-
-	// Prepare the responses of the anticollision phase
-	// there will be not enough time to do this at the moment the reader sends it REQA
-
-	// Answer to request
-	CodeIso14443aAsTag(response1, sizeof(response1));
-	memcpy(resp1, ToSend, ToSendMax); resp1Len = ToSendMax;
-
-	// Send our UID (cascade 1)
-	CodeIso14443aAsTag(response2, sizeof(response2));
-	memcpy(resp2, ToSend, ToSendMax); resp2Len = ToSendMax;
-
-	// Answer to select (cascade1)
-	CodeIso14443aAsTag(response3, sizeof(response3));
-	memcpy(resp3, ToSend, ToSendMax); resp3Len = ToSendMax;
-
-	// Send the cascade 2 2nd part of the uid
-	CodeIso14443aAsTag(response2a, sizeof(response2a));
-	memcpy(resp2a, ToSend, ToSendMax); resp2aLen = ToSendMax;
-
-	// Answer to select (cascade 2)
-	CodeIso14443aAsTag(response3a, sizeof(response3a));
-	memcpy(resp3a, ToSend, ToSendMax); resp3aLen = ToSendMax;
-
-	// Strange answer is an example of rare message size (3 bits)
-	CodeStrangeAnswerAsTag();
-	memcpy(resp4, ToSend, ToSendMax); resp4Len = ToSendMax;
-
-	// Authentication answer (random nonce)
-	CodeIso14443aAsTag(response5, sizeof(response5));
-	memcpy(resp5, ToSend, ToSendMax); resp5Len = ToSendMax;
-
-	// dummy ATS (pseudo-ATR), answer to RATS
-	CodeIso14443aAsTag(response6, sizeof(response6));
-	memcpy(resp6, ToSend, ToSendMax); resp6Len = ToSendMax;
 
 	// We need to listen to the high-frequency, peak-detected path.
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-	FpgaSetupSsc();
+	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
 
 	cmdsRecvd = 0;
+	tag_response_info_t* p_response;
 
 	LED_A_ON();
 	for(;;) {
-	
+		// Clean receive command buffer
+		
 		if(!GetIso14443aCommandFromReader(receivedCmd, &len, RECV_CMD_SIZE)) {
-			DbpString("button press");
+			DbpString("Button press");
 			break;
 		}
+
+		p_response = NULL;
+		
 		// doob - added loads of debug strings so we can see what the reader is saying to us during the sim as hi14alist is not populated
 		// Okay, look at the command now.
 		lastorder = order;
 		if(receivedCmd[0] == 0x26) { // Received a REQUEST
-			resp = resp1; respLen = resp1Len; order = 1;
-			respdata = response1;
-			respsize = sizeof(response1);
+			p_response = &responses[0]; order = 1;
 		} else if(receivedCmd[0] == 0x52) { // Received a WAKEUP
-			resp = resp1; respLen = resp1Len; order = 6;
-			respdata = response1;
-			respsize = sizeof(response1);
+			p_response = &responses[0]; order = 6;
 		} else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x93) {	// Received request for UID (cascade 1)
-			resp = resp2; respLen = resp2Len; order = 2;
-			respdata = response2;
-			respsize = sizeof(response2);
+			p_response = &responses[1]; order = 2;
 		} else if(receivedCmd[1] == 0x20 && receivedCmd[0] == 0x95) { // Received request for UID (cascade 2)
-			resp = resp2a; respLen = resp2aLen; order = 20;
-			respdata = response2a;
-			respsize = sizeof(response2a);
+			p_response = &responses[2]; order = 20;
 		} else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x93) {	// Received a SELECT (cascade 1)
-			resp = resp3; respLen = resp3Len; order = 3;
-			respdata = response3;
-			respsize = sizeof(response3);
+			p_response = &responses[3]; order = 3;
 		} else if(receivedCmd[1] == 0x70 && receivedCmd[0] == 0x95) {	// Received a SELECT (cascade 2)
-			resp = resp3a; respLen = resp3aLen; order = 30;
-			respdata = response3a;
-			respsize = sizeof(response3a);
+			p_response = &responses[4]; order = 30;
 		} else if(receivedCmd[0] == 0x30) {	// Received a (plain) READ
-			resp = resp4; respLen = resp4Len; order = 4; // Do nothing
-			Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
-			respdata = &nack;
-			respsize = sizeof(nack); // 4-bit answer
+			EmSendCmdEx(data+(4*receivedCmd[0]),16,false);
+			// Dbprintf("Read request from reader: %x %x",receivedCmd[0],receivedCmd[1]);
+			// We already responded, do not send anything with the EmSendCmd14443aRaw() that is called below
+			p_response = NULL;
 		} else if(receivedCmd[0] == 0x50) {	// Received a HALT
-			DbpString("Reader requested we HALT!:");
-			// Do not respond
-			resp = resp1; respLen = 0; order = 0;
-			respdata = NULL;
-			respsize = 0;
+//			DbpString("Reader requested we HALT!:");
+			if (tracing) {
+				LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+				LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+			}
+			p_response = NULL;
 		} else if(receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61) {	// Received an authentication request
-			resp = resp5; respLen = resp5Len; order = 7;
-			respdata = response5;
-			respsize = sizeof(response5);
+			p_response = &responses[5]; order = 7;
 		} else if(receivedCmd[0] == 0xE0) {	// Received a RATS request
-			resp = resp6; respLen = resp6Len; order = 70;
-			respdata = response6;
-			respsize = sizeof(response6);
+			if (tagType == 1 || tagType == 2) {	// RATS not supported
+				EmSend4bit(CARD_NACK_NA);
+				p_response = NULL;
+			} else {
+				p_response = &responses[6]; order = 70;
+			}
+		} else if (order == 7 && len == 8) { // Received authentication request
+			if (tracing) {
+				LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+				LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+			}
+			uint32_t nr = bytes_to_num(receivedCmd,4);
+			uint32_t ar = bytes_to_num(receivedCmd+4,4);
+			Dbprintf("Auth attempt {nr}{ar}: %08x %08x",nr,ar);
 		} else {
-			// Never seen this command before
-			Dbprintf("Received (len=%d): %02x %02x %02x %02x %02x %02x %02x %02x %02x",
-			len,
-			receivedCmd[0], receivedCmd[1], receivedCmd[2],
-			receivedCmd[3], receivedCmd[4], receivedCmd[5],
-			receivedCmd[6], receivedCmd[7], receivedCmd[8]);
-			// Do not respond
-			resp = resp1; respLen = 0; order = 0;
-			respdata = NULL;
-			respsize = 0;
+			// Check for ISO 14443A-4 compliant commands, look at left nibble
+			switch (receivedCmd[0]) {
+
+				case 0x0B:
+				case 0x0A: { // IBlock (command)
+				  dynamic_response_info.response[0] = receivedCmd[0];
+				  dynamic_response_info.response[1] = 0x00;
+				  dynamic_response_info.response[2] = 0x90;
+				  dynamic_response_info.response[3] = 0x00;
+				  dynamic_response_info.response_n = 4;
+				} break;
+
+				case 0x1A:
+				case 0x1B: { // Chaining command
+				  dynamic_response_info.response[0] = 0xaa | ((receivedCmd[0]) & 1);
+				  dynamic_response_info.response_n = 2;
+				} break;
+
+				case 0xaa:
+				case 0xbb: {
+				  dynamic_response_info.response[0] = receivedCmd[0] ^ 0x11;
+				  dynamic_response_info.response_n = 2;
+				} break;
+				  
+				case 0xBA: { //
+				  memcpy(dynamic_response_info.response,"\xAB\x00",2);
+				  dynamic_response_info.response_n = 2;
+				} break;
+
+				case 0xCA:
+				case 0xC2: { // Readers sends deselect command
+				  memcpy(dynamic_response_info.response,"\xCA\x00",2);
+				  dynamic_response_info.response_n = 2;
+				} break;
+
+				default: {
+					// Never seen this command before
+					if (tracing) {
+						LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+						LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					}
+					Dbprintf("Received unknown command (len=%d):",len);
+					Dbhexdump(len,receivedCmd,false);
+					// Do not respond
+					dynamic_response_info.response_n = 0;
+				} break;
+			}
+      
+			if (dynamic_response_info.response_n > 0) {
+				// Copy the CID from the reader query
+				dynamic_response_info.response[1] = receivedCmd[1];
+
+				// Add CRC bytes, always used in ISO 14443A-4 compliant cards
+				AppendCrc14443a(dynamic_response_info.response,dynamic_response_info.response_n);
+				dynamic_response_info.response_n += 2;
+        
+				if (prepare_tag_modulation(&dynamic_response_info,DYNAMIC_MODULATION_BUFFER_SIZE) == false) {
+					Dbprintf("Error preparing tag response");
+					if (tracing) {
+						LogTrace(receivedCmd, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+						LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					}
+					break;
+				}
+				p_response = &dynamic_response_info;
+			}
 		}
 
 		// Count number of wakeups received after a halt
@@ -1159,217 +1116,205 @@ void SimulateIso14443aTag(int tagType, int uid_1st, int uid_2nd)
 		// Count number of other messages after a halt
 		if(order != 6 && lastorder == 5) { happened2++; }
 
-		// Look at last parity bit to determine timing of answer
-		if((Uart.parityBits & 0x01) || receivedCmd[0] == 0x52) {
-			// 1236, so correction bit needed
-			//i = 0;
-		}
-
 		if(cmdsRecvd > 999) {
 			DbpString("1000 commands later...");
 			break;
-		} else {
-			cmdsRecvd++;
 		}
-
-		if(respLen > 0) {
-			EmSendCmd14443aRaw(resp, respLen, receivedCmd[0] == 0x52);
+		cmdsRecvd++;
+
+		if (p_response != NULL) {
+			EmSendCmd14443aRaw(p_response->modulation, p_response->modulation_n, receivedCmd[0] == 0x52);
+			// do the tracing for the previous reader request and this tag answer:
+			EmLogTrace(Uart.output, 
+						Uart.len, 
+						Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, 
+						Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 
+						Uart.parityBits,
+						p_response->response, 
+						p_response->response_n,
+						LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
+						(LastTimeProxToAirStart + p_response->ProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG, 
+						SwapBits(GetParity(p_response->response, p_response->response_n), p_response->response_n));
 		}
 		
-		if (tracing) {
-			LogTrace(receivedCmd,len, 0, Uart.parityBits, TRUE);
-			if (respdata != NULL) {
-				LogTrace(respdata,respsize, 0, SwapBits(GetParity(respdata,respsize),respsize), FALSE);
-			}
-			if(traceLen > TRACE_SIZE) {
-				DbpString("Trace full");
-				break;
-			}
+		if (!tracing) {
+			Dbprintf("Trace Full. Simulation stopped.");
+			break;
 		}
-
-		memset(receivedCmd, 0x44, RECV_CMD_SIZE);
-  }
+	}
 
 	Dbprintf("%x %x %x", happened, happened2, cmdsRecvd);
 	LED_A_OFF();
 }
 
-//-----------------------------------------------------------------------------
+
+// prepare a delayed transfer. This simply shifts ToSend[] by a number
+// of bits specified in the delay parameter.
+void PrepareDelayedTransfer(uint16_t delay)
+{
+	uint8_t bitmask = 0;
+	uint8_t bits_to_shift = 0;
+	uint8_t bits_shifted = 0;
+	
+	delay &= 0x07;
+	if (delay) {
+		for (uint16_t i = 0; i < delay; i++) {
+			bitmask |= (0x01 << i);
+		}
+		ToSend[ToSendMax++] = 0x00;
+		for (uint16_t i = 0; i < ToSendMax; i++) {
+			bits_to_shift = ToSend[i] & bitmask;
+			ToSend[i] = ToSend[i] >> delay;
+			ToSend[i] = ToSend[i] | (bits_shifted << (8 - delay));
+			bits_shifted = bits_to_shift;
+		}
+	}
+}
+
+
+//-------------------------------------------------------------------------------------
 // Transmit the command (to the tag) that was placed in ToSend[].
-//-----------------------------------------------------------------------------
-static void TransmitFor14443a(const uint8_t *cmd, int len, int *samples, int *wait)
+// Parameter timing:
+// if NULL: transfer at next possible time, taking into account
+// 			request guard time and frame delay time
+// if == 0:	transfer immediately and return time of transfer
+// if != 0: delay transfer until time specified
+//-------------------------------------------------------------------------------------
+static void TransmitFor14443a(const uint8_t *cmd, int len, uint32_t *timing)
 {
-  int c;
+	
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
 
-  FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
+	uint32_t ThisTransferTime = 0;
 
-	if (wait)
-    if(*wait < 10)
-      *wait = 10;
+	if (timing) {
+		if(*timing == 0) {										// Measure time
+			*timing = (GetCountSspClk() + 8) & 0xfffffff8;
+		} else {
+			PrepareDelayedTransfer(*timing & 0x00000007);		// Delay transfer (fine tuning - up to 7 MF clock ticks)
+		}
+		if(MF_DBGLEVEL >= 4 && GetCountSspClk() >= (*timing & 0xfffffff8)) Dbprintf("TransmitFor14443a: Missed timing");
+		while(GetCountSspClk() < (*timing & 0xfffffff8));		// Delay transfer (multiple of 8 MF clock ticks)
+		LastTimeProxToAirStart = *timing;
+	} else {
+		ThisTransferTime = ((MAX(NextTransferTime, GetCountSspClk()) & 0xfffffff8) + 8);
+		while(GetCountSspClk() < ThisTransferTime);
+		LastTimeProxToAirStart = ThisTransferTime;
+	}
+	
+	// clear TXRDY
+	AT91C_BASE_SSC->SSC_THR = SEC_Y;
 
-  for(c = 0; c < *wait;) {
-    if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-      AT91C_BASE_SSC->SSC_THR = 0x00;		// For exact timing!
-      c++;
-    }
-    if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-      volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
-      (void)r;
-    }
-    WDT_HIT();
-  }
+	// for(uint16_t c = 0; c < 10;) {	// standard delay for each transfer (allow tag to be ready after last transmission)
+		// if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+			// AT91C_BASE_SSC->SSC_THR = SEC_Y;	
+			// c++;
+		// }
+	// }
 
-  c = 0;
-  for(;;) {
-    if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-      AT91C_BASE_SSC->SSC_THR = cmd[c];
-      c++;
-      if(c >= len) {
-        break;
-      }
-    }
-    if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-      volatile uint32_t r = AT91C_BASE_SSC->SSC_RHR;
-      (void)r;
-    }
-    WDT_HIT();
-  }
-	if (samples) *samples = (c + *wait) << 3;
+	uint16_t c = 0;
+	for(;;) {
+		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+			AT91C_BASE_SSC->SSC_THR = cmd[c];
+			c++;
+			if(c >= len) {
+				break;
+			}
+		}
+	}
+	
+	NextTransferTime = MAX(NextTransferTime, LastTimeProxToAirStart + REQUEST_GUARD_TIME);
+	
 }
 
+
 //-----------------------------------------------------------------------------
-// Code a 7-bit command without parity bit
-// This is especially for 0x26 and 0x52 (REQA and WUPA)
+// Prepare reader command (in bits, support short frames) to send to FPGA
 //-----------------------------------------------------------------------------
-void ShortFrameFromReader(const uint8_t bt)
+void CodeIso14443aBitsAsReaderPar(const uint8_t * cmd, int bits, uint32_t dwParity)
 {
-	int j;
+	int i, j;
 	int last;
-  uint8_t b;
+	uint8_t b;
 
 	ToSendReset();
 
 	// Start of Communication (Seq. Z)
 	ToSend[++ToSendMax] = SEC_Z;
+	LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
 	last = 0;
 
-	b = bt;
-	for(j = 0; j < 7; j++) {
-		if(b & 1) {
-			// Sequence X
-			ToSend[++ToSendMax] = SEC_X;
-			last = 1;
-		} else {
-			if(last == 0) {
+	size_t bytecount = nbytes(bits);
+	// Generate send structure for the data bits
+	for (i = 0; i < bytecount; i++) {
+		// Get the current byte to send
+		b = cmd[i];
+		size_t bitsleft = MIN((bits-(i*8)),8);
+
+		for (j = 0; j < bitsleft; j++) {
+			if (b & 1) {
+				// Sequence X
+				ToSend[++ToSendMax] = SEC_X;
+				LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
+				last = 1;
+			} else {
+				if (last == 0) {
 				// Sequence Z
 				ToSend[++ToSendMax] = SEC_Z;
+				LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
+				} else {
+					// Sequence Y
+					ToSend[++ToSendMax] = SEC_Y;
+					last = 0;
+				}
 			}
-			else {
-				// Sequence Y
-				ToSend[++ToSendMax] = SEC_Y;
-				last = 0;
+			b >>= 1;
+		}
+
+		// Only transmit (last) parity bit if we transmitted a complete byte
+		if (j == 8) {
+			// Get the parity bit
+			if ((dwParity >> i) & 0x01) {
+				// Sequence X
+				ToSend[++ToSendMax] = SEC_X;
+				LastProxToAirDuration = 8 * (ToSendMax+1) - 2;
+				last = 1;
+			} else {
+				if (last == 0) {
+					// Sequence Z
+					ToSend[++ToSendMax] = SEC_Z;
+					LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
+				} else {
+					// Sequence Y
+					ToSend[++ToSendMax] = SEC_Y;
+					last = 0;
+				}
 			}
 		}
-		b >>= 1;
 	}
 
-	// End of Communication
-	if(last == 0) {
+	// End of Communication: Logic 0 followed by Sequence Y
+	if (last == 0) {
 		// Sequence Z
 		ToSend[++ToSendMax] = SEC_Z;
-	}
-	else {
+		LastProxToAirDuration = 8 * (ToSendMax+1) - 6;
+	} else {
 		// Sequence Y
 		ToSend[++ToSendMax] = SEC_Y;
 		last = 0;
 	}
-	// Sequence Y
-	ToSend[++ToSendMax] = SEC_Y;
-
-	// Just to be sure!
-	ToSend[++ToSendMax] = SEC_Y;
-	ToSend[++ToSendMax] = SEC_Y;
 	ToSend[++ToSendMax] = SEC_Y;
 
-    // Convert from last character reference to length
-    ToSendMax++;
+	// Convert to length of command:
+	ToSendMax++;
 }
 
 //-----------------------------------------------------------------------------
 // Prepare reader command to send to FPGA
-//
 //-----------------------------------------------------------------------------
 void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
 {
-  int i, j;
-  int last;
-  uint8_t b;
-
-  ToSendReset();
-
-  // Start of Communication (Seq. Z)
-  ToSend[++ToSendMax] = SEC_Z;
-  last = 0;
-
-  // Generate send structure for the data bits
-  for (i = 0; i < len; i++) {
-    // Get the current byte to send
-    b = cmd[i];
-
-    for (j = 0; j < 8; j++) {
-      if (b & 1) {
-        // Sequence X
-    	  ToSend[++ToSendMax] = SEC_X;
-        last = 1;
-      } else {
-        if (last == 0) {
-          // Sequence Z
-        	ToSend[++ToSendMax] = SEC_Z;
-        } else {
-          // Sequence Y
-        	ToSend[++ToSendMax] = SEC_Y;
-          last = 0;
-        }
-      }
-      b >>= 1;
-    }
-
-    // Get the parity bit
-    if ((dwParity >> i) & 0x01) {
-      // Sequence X
-    	ToSend[++ToSendMax] = SEC_X;
-      last = 1;
-    } else {
-      if (last == 0) {
-        // Sequence Z
-    	  ToSend[++ToSendMax] = SEC_Z;
-      } else {
-        // Sequence Y
-    	  ToSend[++ToSendMax] = SEC_Y;
-        last = 0;
-      }
-    }
-  }
-
-  // End of Communication
-  if (last == 0) {
-    // Sequence Z
-	  ToSend[++ToSendMax] = SEC_Z;
-  } else {
-    // Sequence Y
-	  ToSend[++ToSendMax] = SEC_Y;
-    last = 0;
-  }
-  // Sequence Y
-  ToSend[++ToSendMax] = SEC_Y;
-
-  // Just to be sure!
-  ToSend[++ToSendMax] = SEC_Y;
-  ToSend[++ToSendMax] = SEC_Y;
-  ToSend[++ToSendMax] = SEC_Y;
-
-  // Convert from last character reference to length
-  ToSendMax++;
+  CodeIso14443aBitsAsReaderPar(cmd,len*8,dwParity);
 }
 
 //-----------------------------------------------------------------------------
@@ -1377,7 +1322,7 @@ void CodeIso14443aAsReaderPar(const uint8_t * cmd, int len, uint32_t dwParity)
 // Stop when button is pressed (return 1) or field was gone (return 2)
 // Or return 0 when command is captured
 //-----------------------------------------------------------------------------
-static int EmGetCmd(uint8_t *received, int *len, int maxLen)
+static int EmGetCmd(uint8_t *received, int *len)
 {
 	*len = 0;
 
@@ -1402,9 +1347,11 @@ static int EmGetCmd(uint8_t *received, int *len, int maxLen)
 	AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
 	
 	// Now run a 'software UART' on the stream of incoming samples.
+	UartReset();
 	Uart.output = received;
-	Uart.byteCntMax = maxLen;
-	Uart.state = STATE_UNSYNCD;
+
+	// Clear RXRDY:
+    uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 
 	for(;;) {
 		WDT_HIT();
@@ -1428,340 +1375,477 @@ static int EmGetCmd(uint8_t *received, int *len, int maxLen)
 				analogAVG = 0;
 			}
 		}
-		// transmit none
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-			AT91C_BASE_SSC->SSC_THR = 0x00;
-		}
+
 		// receive and test the miller decoding
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-			volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-			if(MillerDecoding((b & 0xf0) >> 4)) {
-				*len = Uart.byteCnt;
-				if (tracing) LogTrace(received, *len, GetDeltaCountUS(), Uart.parityBits, TRUE);
-				return 0;
-			}
-			if(MillerDecoding(b & 0x0f)) {
-				*len = Uart.byteCnt;
-				if (tracing) LogTrace(received, *len, GetDeltaCountUS(), Uart.parityBits, TRUE);
+        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+            b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+			if(MillerDecoding(b, 0)) {
+				*len = Uart.len;
 				return 0;
 			}
-		}
+        }
+
 	}
 }
 
-static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, int correctionNeeded)
-{
-	int i, u = 0;
-	uint8_t b = 0;
 
+static int EmSendCmd14443aRaw(uint8_t *resp, int respLen, bool correctionNeeded)
+{
+	uint8_t b;
+	uint16_t i = 0;
+	uint32_t ThisTransferTime;
+	
 	// Modulate Manchester
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_MOD);
-	AT91C_BASE_SSC->SSC_THR = 0x00;
-	FpgaSetupSsc();
-	
-	// include correction bit
-	i = 1;
-	if((Uart.parityBits & 0x01) || correctionNeeded) {
+
+	// include correction bit if necessary
+	if (Uart.parityBits & 0x01) {
+		correctionNeeded = TRUE;
+	}
+	if(correctionNeeded) {
 		// 1236, so correction bit needed
 		i = 0;
+	} else {
+		i = 1;
 	}
+
+ 	// clear receiving shift register and holding register
+	while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+	b = AT91C_BASE_SSC->SSC_RHR; (void) b;
+	while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+	b = AT91C_BASE_SSC->SSC_RHR; (void) b;
 	
+	// wait for the FPGA to signal fdt_indicator == 1 (the FPGA is ready to queue new data in its delay line)
+	for (uint16_t j = 0; j < 5; j++) {	// allow timeout - better late than never
+		while(!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY));
+		if (AT91C_BASE_SSC->SSC_RHR) break;
+	}
+
+	while ((ThisTransferTime = GetCountSspClk()) & 0x00000007);
+
+	// Clear TXRDY:
+	AT91C_BASE_SSC->SSC_THR = SEC_F;
+
 	// send cycle
-	for(;;) {
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-			volatile uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-			(void)b;
-		}
+	for(; i <= respLen; ) {
 		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-			if(i > respLen) {
-				b = 0xff; // was 0x00
-				u++;
-			} else {
-				b = resp[i];
-				i++;
-			}
-			AT91C_BASE_SSC->SSC_THR = b;
-
-			if(u > 4) break;
+			AT91C_BASE_SSC->SSC_THR = resp[i++];
+			FpgaSendQueueDelay = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
 		}
+	
 		if(BUTTON_PRESS()) {
 			break;
 		}
 	}
 
+	// Ensure that the FPGA Delay Queue is empty before we switch to TAGSIM_LISTEN again:
+	for (i = 0; i < 2 ; ) {
+		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;
 }
 
-int EmSend4bitEx(uint8_t resp, int correctionNeeded){
-  Code4bitAnswerAsTag(resp);
+int EmSend4bitEx(uint8_t resp, bool correctionNeeded){
+	Code4bitAnswerAsTag(resp);
 	int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
-  if (tracing) LogTrace(&resp, 1, GetDeltaCountUS(), GetParity(&resp, 1), FALSE);
+	// do the tracing for the previous reader request and this tag answer:
+	EmLogTrace(Uart.output, 
+				Uart.len, 
+				Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, 
+				Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 
+				Uart.parityBits,
+				&resp, 
+				1, 
+				LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
+				(LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG, 
+				SwapBits(GetParity(&resp, 1), 1));
 	return res;
 }
 
 int EmSend4bit(uint8_t resp){
-	return EmSend4bitEx(resp, 0);
+	return EmSend4bitEx(resp, false);
 }
 
-int EmSendCmdExPar(uint8_t *resp, int respLen, int correctionNeeded, uint32_t par){
-  CodeIso14443aAsTagPar(resp, respLen, par);
+int EmSendCmdExPar(uint8_t *resp, int respLen, bool correctionNeeded, uint32_t par){
+	CodeIso14443aAsTagPar(resp, respLen, par);
 	int res = EmSendCmd14443aRaw(ToSend, ToSendMax, correctionNeeded);
-  if (tracing) LogTrace(resp, respLen, GetDeltaCountUS(), par, FALSE);
+	// do the tracing for the previous reader request and this tag answer:
+	EmLogTrace(Uart.output, 
+				Uart.len, 
+				Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, 
+				Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 
+				Uart.parityBits,
+				resp, 
+				respLen, 
+				LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_TAG,
+				(LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_TAG, 
+				SwapBits(GetParity(resp, respLen), respLen));
 	return res;
 }
 
-int EmSendCmdEx(uint8_t *resp, int respLen, int correctionNeeded){
+int EmSendCmdEx(uint8_t *resp, int respLen, bool correctionNeeded){
 	return EmSendCmdExPar(resp, respLen, correctionNeeded, GetParity(resp, respLen));
 }
 
 int EmSendCmd(uint8_t *resp, int respLen){
-	return EmSendCmdExPar(resp, respLen, 0, GetParity(resp, respLen));
+	return EmSendCmdExPar(resp, respLen, false, GetParity(resp, respLen));
 }
 
 int EmSendCmdPar(uint8_t *resp, int respLen, uint32_t par){
-	return EmSendCmdExPar(resp, respLen, 0, par);
+	return EmSendCmdExPar(resp, respLen, false, par);
+}
+
+bool EmLogTrace(uint8_t *reader_data, uint16_t reader_len, uint32_t reader_StartTime, uint32_t reader_EndTime, uint32_t reader_Parity,
+				 uint8_t *tag_data, uint16_t tag_len, uint32_t tag_StartTime, uint32_t tag_EndTime, uint32_t tag_Parity)
+{
+	if (tracing) {
+		// we cannot exactly measure the end and start of a received command from reader. However we know that the delay from
+		// end of the received command to start of the tag's (simulated by us) answer is n*128+20 or n*128+84 resp.
+		// with n >= 9. The start of the tags answer can be measured and therefore the end of the received command be calculated:
+		uint16_t reader_modlen = reader_EndTime - reader_StartTime;
+		uint16_t approx_fdt = tag_StartTime - reader_EndTime;
+		uint16_t exact_fdt = (approx_fdt - 20 + 32)/64 * 64 + 20;
+		reader_EndTime = tag_StartTime - exact_fdt;
+		reader_StartTime = reader_EndTime - reader_modlen;
+		if (!LogTrace(reader_data, reader_len, reader_StartTime, reader_Parity, TRUE)) {
+			return FALSE;
+		} else if (!LogTrace(NULL, 0, reader_EndTime, 0, TRUE)) {
+			return FALSE;
+		} else if (!LogTrace(tag_data, tag_len, tag_StartTime, tag_Parity, FALSE)) {
+			return FALSE;
+		} else {
+			return (!LogTrace(NULL, 0, tag_EndTime, 0, FALSE));
+		}
+	} else {
+		return TRUE;
+	}
 }
 
 //-----------------------------------------------------------------------------
 // Wait a certain time for tag response
 //  If a response is captured return TRUE
-//  If it takes to long return FALSE
+//  If it takes too long return FALSE
 //-----------------------------------------------------------------------------
-static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, int maxLen, int *samples, int *elapsed) //uint8_t *buffer
+static int GetIso14443aAnswerFromTag(uint8_t *receivedResponse, uint16_t offset, int maxLen)
 {
-	// buffer needs to be 512 bytes
-	int c;
-
+	uint16_t c;
+	
 	// Set FPGA mode to "reader listen mode", no modulation (listen
 	// only, since we are receiving, not transmitting).
 	// Signal field is on with the appropriate LED
 	LED_D_ON();
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
-
+	
 	// Now get the answer from the card
+	DemodReset();
 	Demod.output = receivedResponse;
-	Demod.len = 0;
-	Demod.state = DEMOD_UNSYNCD;
-
-	uint8_t b;
-	if (elapsed) *elapsed = 0;
 
+	// clear RXRDY:
+    uint8_t b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+	
 	c = 0;
 	for(;;) {
 		WDT_HIT();
 
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-			AT91C_BASE_SSC->SSC_THR = 0x00;  // To make use of exact timing of next command from reader!!
-			if (elapsed) (*elapsed)++;
-		}
 		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-			if(c < iso14a_timeout) { c++; } else { return FALSE; }
 			b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-			if(ManchesterDecoding((b>>4) & 0xf)) {
-				*samples = ((c - 1) << 3) + 4;
-				return TRUE;
-			}
-			if(ManchesterDecoding(b & 0x0f)) {
-				*samples = c << 3;
+			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) {
+				return FALSE; 
 			}
 		}
 	}
 }
 
-void ReaderTransmitShort(const uint8_t* bt)
+void ReaderTransmitBitsPar(uint8_t* frame, int bits, uint32_t par, uint32_t *timing)
 {
-  int wait = 0;
-  int samples = 0;
 
-  ShortFrameFromReader(*bt);
-
-  // Select the card
-  TransmitFor14443a(ToSend, ToSendMax, &samples, &wait);
-
-  // Store reader command in buffer
-  if (tracing) LogTrace(bt,1,0,GetParity(bt,1),TRUE);
+	CodeIso14443aBitsAsReaderPar(frame,bits,par);
+  
+	// Send command to tag
+	TransmitFor14443a(ToSend, ToSendMax, timing);
+	if(trigger)
+		LED_A_ON();
+  
+	// Log reader command in trace buffer
+	if (tracing) {
+		LogTrace(frame, nbytes(bits), LastTimeProxToAirStart*16 + DELAY_ARM2AIR_AS_READER, par, TRUE);
+		LogTrace(NULL, 0, (LastTimeProxToAirStart + LastProxToAirDuration)*16 + DELAY_ARM2AIR_AS_READER, 0, TRUE);
+	}
 }
 
-void ReaderTransmitPar(uint8_t* frame, int len, uint32_t par)
+void ReaderTransmitPar(uint8_t* frame, int len, uint32_t par, uint32_t *timing)
 {
-  int wait = 0;
-  int samples = 0;
-
-  // This is tied to other size changes
-  // 	uint8_t* frame_addr = ((uint8_t*)BigBuf) + 2024;
-  CodeIso14443aAsReaderPar(frame,len,par);
-
-  // Select the card
-  TransmitFor14443a(ToSend, ToSendMax, &samples, &wait);
-  if(trigger)
-  	LED_A_ON();
-
-  // Store reader command in buffer
-  if (tracing) LogTrace(frame,len,0,par,TRUE);
+  ReaderTransmitBitsPar(frame,len*8,par, timing);
 }
 
+void ReaderTransmitBits(uint8_t* frame, int len, uint32_t *timing)
+{
+  // Generate parity and redirect
+  ReaderTransmitBitsPar(frame,len,GetParity(frame,len/8), timing);
+}
 
-void ReaderTransmit(uint8_t* frame, int len)
+void ReaderTransmit(uint8_t* frame, int len, uint32_t *timing)
 {
   // Generate parity and redirect
-  ReaderTransmitPar(frame,len,GetParity(frame,len));
+  ReaderTransmitBitsPar(frame,len*8,GetParity(frame,len), timing);
+}
+
+int ReaderReceiveOffset(uint8_t* receivedAnswer, uint16_t offset)
+{
+	if (!GetIso14443aAnswerFromTag(receivedAnswer,offset,160)) return FALSE;
+	if (tracing) {
+		LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.parityBits, FALSE);
+		LogTrace(NULL, 0, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, 0, FALSE);
+	}
+	return Demod.len;
 }
 
 int ReaderReceive(uint8_t* receivedAnswer)
 {
-  int samples = 0;
-  if (!GetIso14443aAnswerFromTag(receivedAnswer,160,&samples,0)) return FALSE;
-  if (tracing) LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE);
-  if(samples == 0) return FALSE;
-  return Demod.len;
+	return ReaderReceiveOffset(receivedAnswer, 0);
 }
 
-int ReaderReceivePar(uint8_t* receivedAnswer, uint32_t * parptr)
+int ReaderReceivePar(uint8_t *receivedAnswer, uint32_t *parptr)
 {
-  int samples = 0;
-  if (!GetIso14443aAnswerFromTag(receivedAnswer,160,&samples,0)) return FALSE;
-  if (tracing) LogTrace(receivedAnswer,Demod.len,samples,Demod.parityBits,FALSE);
+	if (!GetIso14443aAnswerFromTag(receivedAnswer,0,160)) return FALSE;
+	if (tracing) {
+		LogTrace(receivedAnswer, Demod.len, Demod.startTime*16 - DELAY_AIR2ARM_AS_READER, Demod.parityBits, FALSE);
+		LogTrace(NULL, 0, Demod.endTime*16 - DELAY_AIR2ARM_AS_READER, 0, FALSE);
+	}
 	*parptr = Demod.parityBits;
-  if(samples == 0) return FALSE;
-  return Demod.len;
+	return Demod.len;
 }
 
-/* performs iso14443a anticolision procedure
+/* performs iso14443a anticollision procedure
  * fills the uid pointer unless NULL
  * fills resp_data unless NULL */
-int iso14443a_select_card(uint8_t * uid_ptr, iso14a_card_select_t * resp_data, uint32_t * cuid_ptr) {
-	uint8_t wupa[]       = { 0x52 };  // 0x26 - REQA  0x52 - WAKE-UP
-	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
+int iso14443a_select_card(byte_t* uid_ptr, iso14a_card_select_t* p_hi14a_card, uint32_t* cuid_ptr) {
+  uint8_t wupa[]       = { 0x52 };  // 0x26 - REQA  0x52 - WAKE-UP
+  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) + FREE_BUFFER_OFFSET);	// was 3560 - tied to other size changes
+  byte_t uid_resp[4];
+  size_t uid_resp_len;
+
+  uint8_t sak = 0x04; // cascade uid
+  int cascade_level = 0;
+  int len;
+	 
+  // Broadcast for a card, WUPA (0x52) will force response from all cards in the field
+    ReaderTransmitBitsPar(wupa,7,0, NULL);
+	
+  // Receive the ATQA
+  if(!ReaderReceive(resp)) return 0;
+  // Dbprintf("atqa: %02x %02x",resp[0],resp[1]);
+
+  if(p_hi14a_card) {
+    memcpy(p_hi14a_card->atqa, resp, 2);
+    p_hi14a_card->uidlen = 0;
+    memset(p_hi14a_card->uid,0,10);
+  }
 
-	uint8_t* resp = (((uint8_t *)BigBuf) + 3560);	// was 3560 - tied to other size changes
+  // clear uid
+  if (uid_ptr) {
+    memset(uid_ptr,0,10);
+  }
 
-	uint8_t sak = 0x04; // cascade uid
-	int cascade_level = 0;
+  // 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.
+  for(; sak & 0x04; cascade_level++) {
+    // SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97)
+    sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2;
+
+    // SELECT_ALL
+    ReaderTransmit(sel_all,sizeof(sel_all), NULL);
+    if (!ReaderReceive(resp)) return 0;
+
+	if (Demod.collisionPos) {			// we had a collision and need to construct the UID bit by bit
+		memset(uid_resp, 0, 4);
+		uint16_t uid_resp_bits = 0;
+		uint16_t collision_answer_offset = 0;
+		// anti-collision-loop:
+		while (Demod.collisionPos) {
+			Dbprintf("Multiple tags detected. Collision after Bit %d", Demod.collisionPos);
+			for (uint16_t i = collision_answer_offset; i < Demod.collisionPos; i++, uid_resp_bits++) {	// add valid UID bits before collision point
+				uint16_t UIDbit = (resp[i/8] >> (i % 8)) & 0x01;
+				uid_resp[uid_resp_bits & 0xf8] |= UIDbit << (uid_resp_bits % 8);
+			}
+			uid_resp[uid_resp_bits/8] |= 1 << (uid_resp_bits % 8);					// next time select the card(s) with a 1 in the collision position
+			uid_resp_bits++;
+			// construct anticollosion command:
+			sel_uid[1] = ((2 + uid_resp_bits/8) << 4) | (uid_resp_bits & 0x07);  	// length of data in bytes and bits
+			for (uint16_t i = 0; i <= uid_resp_bits/8; i++) {
+				sel_uid[2+i] = uid_resp[i];
+			}
+			collision_answer_offset = uid_resp_bits%8;
+			ReaderTransmitBits(sel_uid, 16 + uid_resp_bits, NULL);
+			if (!ReaderReceiveOffset(resp, collision_answer_offset)) return 0;
+		}
+		// finally, add the last bits and BCC of the UID
+		for (uint16_t i = collision_answer_offset; i < (Demod.len-1)*8; i++, uid_resp_bits++) {
+			uint16_t UIDbit = (resp[i/8] >> (i%8)) & 0x01;
+			uid_resp[uid_resp_bits/8] |= UIDbit << (uid_resp_bits % 8);
+		}
 
-	int len;
-	
-	// clear uid
-	memset(uid_ptr, 0, 8);
+	} else {		// no collision, use the response to SELECT_ALL as current uid
+		memcpy(uid_resp,resp,4);
+	}
+	uid_resp_len = 4;
+       // Dbprintf("uid: %02x %02x %02x %02x",uid_resp[0],uid_resp[1],uid_resp[2],uid_resp[3]);
 
-	// Broadcast for a card, WUPA (0x52) will force response from all cards in the field
-	ReaderTransmitShort(wupa);
-	// Receive the ATQA
-	if(!ReaderReceive(resp)) return 0;
+    // calculate crypto UID. Always use last 4 Bytes.
+    if(cuid_ptr) {
+        *cuid_ptr = bytes_to_num(uid_resp, 4);
+    }
 
-	if(resp_data)
-		memcpy(resp_data->atqa, resp, 2);
-	
-	// 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.
-	for(; sak & 0x04; cascade_level++)
-	{
-		// SELECT_* (L1: 0x93, L2: 0x95, L3: 0x97)
-		sel_uid[0] = sel_all[0] = 0x93 + cascade_level * 2;
+    // Construct SELECT UID command
+	sel_uid[1] = 0x70;													// transmitting a full UID (1 Byte cmd, 1 Byte NVB, 4 Byte UID, 1 Byte BCC, 2 Bytes CRC)
+    memcpy(sel_uid+2,uid_resp,4);										// the UID
+	sel_uid[6] = sel_uid[2] ^ sel_uid[3] ^ sel_uid[4] ^ sel_uid[5];  	// calculate and add BCC
+    AppendCrc14443a(sel_uid,7);											// calculate and add CRC
+    ReaderTransmit(sel_uid,sizeof(sel_uid), NULL);
+
+    // Receive the SAK
+    if (!ReaderReceive(resp)) return 0;
+    sak = resp[0];
+
+    // Test if more parts of the uid are comming
+    if ((sak & 0x04) /* && uid_resp[0] == 0x88 */) {
+      // Remove first byte, 0x88 is not an UID byte, it CT, see page 3 of:
+      // http://www.nxp.com/documents/application_note/AN10927.pdf
+      memcpy(uid_resp, uid_resp + 1, 3);
+      uid_resp_len = 3;
+    }
 
-		// SELECT_ALL
-		ReaderTransmit(sel_all,sizeof(sel_all));
-		if (!ReaderReceive(resp)) return 0;
-		if(uid_ptr) memcpy(uid_ptr + cascade_level*4, resp, 4);
-		
-		// calculate crypto UID
-		if(cuid_ptr) *cuid_ptr = bytes_to_num(resp, 4);
+    if(uid_ptr) {
+      memcpy(uid_ptr + (cascade_level*3), uid_resp, uid_resp_len);
+    }
 
-		// Construct SELECT UID command
-		memcpy(sel_uid+2,resp,5);
-		AppendCrc14443a(sel_uid,7);
-		ReaderTransmit(sel_uid,sizeof(sel_uid));
+    if(p_hi14a_card) {
+      memcpy(p_hi14a_card->uid + (cascade_level*3), uid_resp, uid_resp_len);
+      p_hi14a_card->uidlen += uid_resp_len;
+    }
+  }
 
-		// Receive the SAK
-		if (!ReaderReceive(resp)) return 0;
-		sak = resp[0];
-	}
-	if(resp_data) {
-		resp_data->sak = sak;
-		resp_data->ats_len = 0;
-	}
-	//--  this byte not UID, it CT.  http://www.nxp.com/documents/application_note/AN10927.pdf  page 3
-	if (uid_ptr[0] == 0x88) {  
-		memcpy(uid_ptr, uid_ptr + 1, 7);
-		uid_ptr[7] = 0;
-	}
+  if(p_hi14a_card) {
+    p_hi14a_card->sak = sak;
+    p_hi14a_card->ats_len = 0;
+  }
 
-	if( (sak & 0x20) == 0)
-		return 2; // non iso14443a compliant tag
+  if( (sak & 0x20) == 0) {
+    return 2; // non iso14443a compliant tag
+  }
 
-	// Request for answer to select
-	if(resp_data) {  // JCOP cards - if reader sent RATS then there is no MIFARE session at all!!!
-		AppendCrc14443a(rats, 2);
-		ReaderTransmit(rats, sizeof(rats));
-		
-		if (!(len = ReaderReceive(resp))) return 0;
-		
-		memcpy(resp_data->ats, resp, sizeof(resp_data->ats));
-		resp_data->ats_len = len;
-	}
-	
-	return 1;
+  // Request for answer to select
+  AppendCrc14443a(rats, 2);
+  ReaderTransmit(rats, sizeof(rats), NULL);
+
+  if (!(len = ReaderReceive(resp))) return 0;
+
+  if(p_hi14a_card) {
+    memcpy(p_hi14a_card->ats, resp, sizeof(p_hi14a_card->ats));
+    p_hi14a_card->ats_len = len;
+  }
+
+  // reset the PCB block number
+  iso14_pcb_blocknum = 0;
+  return 1;
 }
 
-void iso14443a_setup() {
-	// Setup SSC
+void iso14443a_setup(uint8_t fpga_minor_mode) {
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	// Set up the synchronous serial port
 	FpgaSetupSsc();
-	// Start from off (no field generated)
-	// Signal field is off with the appropriate LED
-	LED_D_OFF();
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	SpinDelay(200);
-
+	// connect Demodulated Signal to ADC:
 	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
-	// Now give it time to spin up.
 	// Signal field is on with the appropriate LED
-	LED_D_ON();
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-	SpinDelay(200);
+	if (fpga_minor_mode == FPGA_HF_ISO14443A_READER_MOD
+		|| fpga_minor_mode == FPGA_HF_ISO14443A_READER_LISTEN) {
+		LED_D_ON();
+	} else {
+		LED_D_OFF();
+	}
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | fpga_minor_mode);
 
-	iso14a_timeout = 2048; //default
+	// Start the timer
+	StartCountSspClk();
+	
+	DemodReset();
+	UartReset();
+	NextTransferTime = 2*DELAY_ARM2AIR_AS_READER;
+	iso14a_set_timeout(1050); // 10ms default
 }
 
 int iso14_apdu(uint8_t * cmd, size_t cmd_len, void * data) {
 	uint8_t real_cmd[cmd_len+4];
 	real_cmd[0] = 0x0a; //I-Block
+	// put block number into the PCB
+	real_cmd[0] |= iso14_pcb_blocknum;
 	real_cmd[1] = 0x00; //CID: 0 //FIXME: allow multiple selected cards
 	memcpy(real_cmd+2, cmd, cmd_len);
 	AppendCrc14443a(real_cmd,cmd_len+2);
  
-	ReaderTransmit(real_cmd, cmd_len+4);
+	ReaderTransmit(real_cmd, cmd_len+4, NULL);
 	size_t len = ReaderReceive(data);
-	if(!len)
-		return -1; //DATA LINK ERROR
-	
+	uint8_t * data_bytes = (uint8_t *) data;
+	if (!len)
+		return 0; //DATA LINK ERROR
+	// if we received an I- or R(ACK)-Block with a block number equal to the
+	// current block number, toggle the current block number
+	else if (len >= 4 // PCB+CID+CRC = 4 bytes
+	         && ((data_bytes[0] & 0xC0) == 0 // I-Block
+	             || (data_bytes[0] & 0xD0) == 0x80) // R-Block with ACK bit set to 0
+	         && (data_bytes[0] & 0x01) == iso14_pcb_blocknum) // equal block numbers
+	{
+		iso14_pcb_blocknum ^= 1;
+	}
+
 	return len;
 }
 
-
 //-----------------------------------------------------------------------------
 // Read an ISO 14443a tag. Send out commands and store answers.
 //
 //-----------------------------------------------------------------------------
-void ReaderIso14443a(UsbCommand * c, UsbCommand * ack)
+void ReaderIso14443a(UsbCommand *c)
 {
 	iso14a_command_t param = c->arg[0];
-	uint8_t * cmd = c->d.asBytes;
+	uint8_t *cmd = c->d.asBytes;
 	size_t len = c->arg[1];
+	size_t lenbits = c->arg[2];
+	uint32_t arg0 = 0;
+	byte_t buf[USB_CMD_DATA_SIZE];
+  
+	if(param & ISO14A_CONNECT) {
+		iso14a_clear_trace();
+	}
 
-	if(param & ISO14A_REQUEST_TRIGGER) iso14a_set_trigger(1);
+	iso14a_set_tracing(TRUE);
 
-	if(param & ISO14A_CONNECT) {
-		iso14443a_setup();
-		ack->arg[0] = iso14443a_select_card(ack->d.asBytes, (iso14a_card_select_t *) (ack->d.asBytes+12), NULL);
-		UsbSendPacket((void *)ack, sizeof(UsbCommand));
+	if(param & ISO14A_REQUEST_TRIGGER) {
+		iso14a_set_trigger(TRUE);
 	}
 
-	if(param & ISO14A_SET_TIMEOUT) {
-		iso14a_timeout = c->arg[2];
+	if(param & ISO14A_CONNECT) {
+		iso14443a_setup(FPGA_HF_ISO14443A_READER_LISTEN);
+		if(!(param & ISO14A_NO_SELECT)) {
+			iso14a_card_select_t *card = (iso14a_card_select_t*)buf;
+			arg0 = iso14443a_select_card(NULL,card,NULL);
+			cmd_send(CMD_ACK,arg0,card->uidlen,0,buf,sizeof(iso14a_card_select_t));
+		}
 	}
 
 	if(param & ISO14A_SET_TIMEOUT) {
@@ -1769,108 +1853,217 @@ void ReaderIso14443a(UsbCommand * c, UsbCommand * ack)
 	}
 
 	if(param & ISO14A_APDU) {
-		ack->arg[0] = iso14_apdu(cmd, len, ack->d.asBytes);
-		UsbSendPacket((void *)ack, sizeof(UsbCommand));
+		arg0 = iso14_apdu(cmd, len, buf);
+		cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
 	}
 
 	if(param & ISO14A_RAW) {
 		if(param & ISO14A_APPEND_CRC) {
 			AppendCrc14443a(cmd,len);
 			len += 2;
+			lenbits += 16;
+		}
+		if(lenbits>0) {
+
+			ReaderTransmitBitsPar(cmd,lenbits,GetParity(cmd,lenbits/8), NULL);
+		} else {
+			ReaderTransmit(cmd,len, NULL);
 		}
-		ReaderTransmit(cmd,len);
-		ack->arg[0] = ReaderReceive(ack->d.asBytes);
-		UsbSendPacket((void *)ack, sizeof(UsbCommand));
+		arg0 = ReaderReceive(buf);
+		cmd_send(CMD_ACK,arg0,0,0,buf,sizeof(buf));
 	}
 
-	if(param & ISO14A_REQUEST_TRIGGER) iso14a_set_trigger(0);
+	if(param & ISO14A_REQUEST_TRIGGER) {
+		iso14a_set_trigger(FALSE);
+	}
 
-	if(param & ISO14A_NO_DISCONNECT)
+	if(param & ISO14A_NO_DISCONNECT) {
 		return;
+	}
 
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 	LEDsoff();
 }
+
+
+// Determine the distance between two nonces.
+// Assume that the difference is small, but we don't know which is first.
+// Therefore try in alternating directions.
+int32_t dist_nt(uint32_t nt1, uint32_t nt2) {
+
+	uint16_t i;
+	uint32_t nttmp1, nttmp2;
+
+	if (nt1 == nt2) return 0;
+
+	nttmp1 = nt1;
+	nttmp2 = nt2;
+	
+	for (i = 1; i < 32768; i++) {
+		nttmp1 = prng_successor(nttmp1, 1);
+		if (nttmp1 == nt2) return i;
+		nttmp2 = prng_successor(nttmp2, 1);
+			if (nttmp2 == nt1) return -i;
+		}
+	
+	return(-99999); // either nt1 or nt2 are invalid nonces
+}
+
+
 //-----------------------------------------------------------------------------
-// Read an ISO 14443a tag. Send out commands and store answers.
-//
+// Recover several bits of the cypher stream. This implements (first stages of)
+// the algorithm described in "The Dark Side of Security by Obscurity and
+// Cloning MiFare Classic Rail and Building Passes, Anywhere, Anytime"
+// (article by Nicolas T. Courtois, 2009)
 //-----------------------------------------------------------------------------
-void ReaderMifare(uint32_t parameter)
+void ReaderMifare(bool first_try)
 {
 	// Mifare AUTH
 	uint8_t mf_auth[]    = { 0x60,0x00,0xf5,0x7b };
 	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) + 3560);	// was 3560 - tied to other size changes
-	traceLen = 0;
-	tracing = false;
-
-	iso14443a_setup();
+	uint8_t* receivedAnswer = (((uint8_t *)BigBuf) + FREE_BUFFER_OFFSET);
 
-	LED_A_ON();
-	LED_B_OFF();
-	LED_C_OFF();
+	iso14a_clear_trace();
+	iso14a_set_tracing(TRUE);
 
 	byte_t nt_diff = 0;
-	LED_A_OFF();
 	byte_t par = 0;
 	//byte_t par_mask = 0xff;
-	byte_t par_low = 0;
-	int led_on = TRUE;
-	uint8_t uid[8];
+	static byte_t par_low = 0;
+	bool led_on = TRUE;
+	uint8_t uid[10];
 	uint32_t cuid;
 
-	tracing = FALSE;
-	byte_t nt[4] = {0,0,0,0};
-	byte_t nt_attacked[4], nt_noattack[4];
+	uint32_t nt, previous_nt;
+	static uint32_t nt_attacked = 0;
 	byte_t par_list[8] = {0,0,0,0,0,0,0,0};
 	byte_t ks_list[8] = {0,0,0,0,0,0,0,0};
-	num_to_bytes(parameter, 4, nt_noattack);
-	int isOK = 0, isNULL = 0;
 
-	while(TRUE)
-	{
-		LED_C_ON();
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-		SpinDelay(200);
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-		LED_C_OFF();
+	static uint32_t sync_time;
+	static uint32_t sync_cycles;
+	int catch_up_cycles = 0;
+	int last_catch_up = 0;
+	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).
+		nt_attacked = 0;
+		nt = 0;
+		par = 0;
+	}
+	else {
+		// we were unsuccessful on a previous call. Try another READER nonce (first 3 parity bits remain the same)
+		// nt_attacked = prng_successor(nt_attacked, 1);
+		mf_nr_ar3++;
+		mf_nr_ar[3] = mf_nr_ar3;
+		par = par_low;
+	}
+
+	LED_A_ON();
+	LED_B_OFF();
+	LED_C_OFF();
+	
+  
+	for(uint16_t i = 0; TRUE; i++) {
+		
+		WDT_HIT();
 
 		// Test if the action was cancelled
 		if(BUTTON_PRESS()) {
 			break;
 		}
+		
+		LED_C_ON();
+
+		if(!iso14443a_select_card(uid, NULL, &cuid)) {
+			if (MF_DBGLEVEL >= 1)	Dbprintf("Mifare: Can't select card");
+			continue;
+		}
 
-		if(!iso14443a_select_card(uid, NULL, &cuid)) continue;
+		sync_time = (sync_time & 0xfffffff8) + sync_cycles + catch_up_cycles;
+		catch_up_cycles = 0;
 
-		// Transmit MIFARE_CLASSIC_AUTH
-		ReaderTransmit(mf_auth, sizeof(mf_auth));
+		// if we missed the sync time already, advance to the next nonce repeat
+		while(GetCountSspClk() > sync_time) {
+			sync_time = (sync_time & 0xfffffff8) + sync_cycles;
+		}
 
-		// Receive the (16 bit) "random" nonce
-		if (!ReaderReceive(receivedAnswer)) continue;
-		memcpy(nt, receivedAnswer, 4);
+		// 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 reader nonce and reader answer
-		ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar),par);
+		// Receive the (4 Byte) "random" nonce
+		if (!ReaderReceive(receivedAnswer)) {
+			if (MF_DBGLEVEL >= 1)	Dbprintf("Mifare: Couldn't receive tag nonce");
+			continue;
+		  }
 
-		// Receive 4 bit answer
-		if (ReaderReceive(receivedAnswer))
-		{
-			if ( (parameter != 0) && (memcmp(nt, nt_noattack, 4) == 0) ) continue;
+		previous_nt = nt;
+		nt = bytes_to_num(receivedAnswer, 4);
+
+		// Transmit reader nonce with fake par
+		ReaderTransmitPar(mf_nr_ar, sizeof(mf_nr_ar), par, NULL);
 
-			isNULL = !(nt_attacked[0] == 0) && (nt_attacked[1] == 0) && (nt_attacked[2] == 0) && (nt_attacked[3] == 0);
-			if ( (isNULL != 0 ) && (memcmp(nt, nt_attacked, 4) != 0) ) continue;
+		if (first_try && previous_nt && !nt_attacked) { // we didn't calibrate our clock yet
+			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;
+				}
+				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;
+			}
+		}
 
+		if ((nt != nt_attacked) && nt_attacked) { 	// we somehow lost sync. Try to catch up again...
+			catch_up_cycles = -dist_nt(nt_attacked, nt);
+			if (catch_up_cycles == 99999) {			// invalid nonce received. Don't resync on that one.
+				catch_up_cycles = 0;
+				continue;
+			}
+			if (catch_up_cycles == last_catch_up) {
+				consecutive_resyncs++;
+			}
+			else {
+				last_catch_up = catch_up_cycles;
+			    consecutive_resyncs = 0;
+			}
+			if (consecutive_resyncs < 3) {
+				if (MF_DBGLEVEL >= 3) Dbprintf("Lost sync in cycle %d. nt_distance=%d. Consecutive Resyncs = %d. Trying one time catch up...\n", i, -catch_up_cycles, consecutive_resyncs);
+			}
+			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);
+			}
+			continue;
+		}
+ 
+		consecutive_resyncs = 0;
+		
+		// Receive answer. This will be a 4 Bit NACK when the 8 parity bits are OK after decoding
+		if (ReaderReceive(receivedAnswer))
+		{
+			catch_up_cycles = 8; 	// the PRNG is delayed by 8 cycles due to the NAC (4Bits = 0x05 encrypted) transfer
+	
 			if (nt_diff == 0)
 			{
-				LED_A_ON();
-				memcpy(nt_attacked, nt, 4);
-				//par_mask = 0xf8;
-				par_low = par & 0x07;
+				par_low = par & 0x07; // there is no need to check all parities for other nt_diff. Parity Bits for mf_nr_ar[0..2] won't change
 			}
 
 			led_on = !led_on;
 			if(led_on) LED_B_ON(); else LED_B_OFF();
+
 			par_list[nt_diff] = par;
 			ks_list[nt_diff] = receivedAnswer[0] ^ 0x05;
 
@@ -1881,10 +2074,10 @@ void ReaderMifare(uint32_t parameter)
 			}
 
 			nt_diff = (nt_diff + 1) & 0x07;
-			mf_nr_ar[3] = nt_diff << 5;
+			mf_nr_ar[3] = (mf_nr_ar[3] & 0x1F) | (nt_diff << 5);
 			par = par_low;
 		} else {
-			if (nt_diff == 0)
+			if (nt_diff == 0 && first_try)
 			{
 				par++;
 			} else {
@@ -1893,41 +2086,41 @@ void ReaderMifare(uint32_t parameter)
 		}
 	}
 
-	LogTrace(nt, 4, 0, GetParity(nt, 4), TRUE);
-	LogTrace(par_list, 8, 0, GetParity(par_list, 8), TRUE);
-	LogTrace(ks_list, 8, 0, GetParity(ks_list, 8), TRUE);
 
-	UsbCommand ack = {CMD_ACK, {isOK, 0, 0}};
-	memcpy(ack.d.asBytes + 0,  uid, 4);
-	memcpy(ack.d.asBytes + 4,  nt, 4);
-	memcpy(ack.d.asBytes + 8,  par_list, 8);
-	memcpy(ack.d.asBytes + 16, ks_list, 8);
+	mf_nr_ar[3] &= 0x1F;
+	
+	byte_t buf[28];
+	memcpy(buf + 0,  uid, 4);
+	num_to_bytes(nt, 4, buf + 4);
+	memcpy(buf + 8,  par_list, 8);
+	memcpy(buf + 16, ks_list, 8);
+	memcpy(buf + 24, mf_nr_ar, 4);
 		
-	LED_B_ON();
-	UsbSendPacket((uint8_t *)&ack, sizeof(UsbCommand));
-	LED_B_OFF();	
+	cmd_send(CMD_ACK,isOK,0,0,buf,28);
 
 	// Thats it...
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 	LEDsoff();
-	tracing = TRUE;
-	
-	if (MF_DBGLEVEL >= 1)	DbpString("COMMAND mifare FINISHED");
-}
 
+	iso14a_set_tracing(FALSE);
+}
 
-//-----------------------------------------------------------------------------
-// MIFARE 1K simulate. 
-// 
-//-----------------------------------------------------------------------------
-void Mifare1ksim(uint8_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
+/**
+  *MIFARE 1K simulate.
+  *
+  *@param flags :
+  *	FLAG_INTERACTIVE - In interactive mode, we are expected to finish the operation with an ACK
+  * 4B_FLAG_UID_IN_DATA - means that there is a 4-byte UID in the data-section, we're expected to use that
+  * 7B_FLAG_UID_IN_DATA - means that there is a 7-byte UID in the data-section, we're expected to use that
+  *	FLAG_NR_AR_ATTACK  - means we should collect NR_AR responses for bruteforcing later
+  *@param exitAfterNReads, exit simulation after n blocks have been read, 0 is inifite
+  */
+void Mifare1ksim(uint8_t flags, uint8_t exitAfterNReads, uint8_t arg2, uint8_t *datain)
 {
 	int cardSTATE = MFEMUL_NOFIELD;
 	int _7BUID = 0;
 	int vHf = 0;	// in mV
-	//int nextCycleTimeout = 0;
 	int res;
-//	uint32_t timer = 0;
 	uint32_t selTimer = 0;
 	uint32_t authTimer = 0;
 	uint32_t par = 0;
@@ -1935,7 +2128,6 @@ void Mifare1ksim(uint8_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
 	uint8_t cardWRBL = 0;
 	uint8_t cardAUTHSC = 0;
 	uint8_t cardAUTHKEY = 0xff;  // no authentication
-	//uint32_t cardRn = 0;
 	uint32_t cardRr = 0;
 	uint32_t cuid = 0;
 	//uint32_t rn_enc = 0;
@@ -1945,69 +2137,84 @@ void Mifare1ksim(uint8_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
 	struct Crypto1State mpcs = {0, 0};
 	struct Crypto1State *pcs;
 	pcs = &mpcs;
-	
+	uint32_t numReads = 0;//Counts numer of times reader read a block
 	uint8_t* receivedCmd = eml_get_bigbufptr_recbuf();
 	uint8_t *response = eml_get_bigbufptr_sendbuf();
 	
-	static uint8_t rATQA[] = {0x04, 0x00}; // Mifare classic 1k 4BUID
-
-	static uint8_t rUIDBCC1[] = {0xde, 0xad, 0xbe, 0xaf, 0x62}; 
-	static uint8_t rUIDBCC2[] = {0xde, 0xad, 0xbe, 0xaf, 0x62}; // !!!
+	uint8_t rATQA[] = {0x04, 0x00}; // Mifare classic 1k 4BUID
+	uint8_t rUIDBCC1[] = {0xde, 0xad, 0xbe, 0xaf, 0x62};
+	uint8_t rUIDBCC2[] = {0xde, 0xad, 0xbe, 0xaf, 0x62}; // !!!
+	uint8_t rSAK[] = {0x08, 0xb6, 0xdd};
+	uint8_t rSAK1[] = {0x04, 0xda, 0x17};
+
+	uint8_t rAUTH_NT[] = {0x01, 0x02, 0x03, 0x04};
+	uint8_t rAUTH_AT[] = {0x00, 0x00, 0x00, 0x00};
 		
-	static uint8_t rSAK[] = {0x08, 0xb6, 0xdd};
-	static uint8_t rSAK1[] = {0x04, 0xda, 0x17};
-
-	static uint8_t rAUTH_NT[] = {0x01, 0x02, 0x03, 0x04};
-//	static uint8_t rAUTH_NT[] = {0x1a, 0xac, 0xff, 0x4f};
-	static uint8_t rAUTH_AT[] = {0x00, 0x00, 0x00, 0x00};
+	//Here, we collect UID,NT,AR,NR,UID2,NT2,AR2,NR2
+	// This can be used in a reader-only attack.
+	// (it can also be retrieved via 'hf 14a list', but hey...
+	uint32_t ar_nr_responses[] = {0,0,0,0,0,0,0,0};
+	uint8_t ar_nr_collected = 0;
 
 	// clear trace
-	traceLen = 0;
-	tracing = true;
+    iso14a_clear_trace();
+	iso14a_set_tracing(TRUE);
 
-  // Authenticate response - nonce
+	// Authenticate response - nonce
 	uint32_t nonce = bytes_to_num(rAUTH_NT, 4);
 	
-	// get UID from emul memory
-	emlGetMemBt(receivedCmd, 7, 1);
-	_7BUID = !(receivedCmd[0] == 0x00);
-	if (!_7BUID) {                     // ---------- 4BUID
-		rATQA[0] = 0x04;
-
-		emlGetMemBt(rUIDBCC1, 0, 4);
+	//-- Determine the UID
+	// Can be set from emulator memory, incoming data
+	// and can be 7 or 4 bytes long
+	if (flags & FLAG_4B_UID_IN_DATA)
+	{
+		// 4B uid comes from data-portion of packet
+		memcpy(rUIDBCC1,datain,4);
 		rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
-	} else {                           // ---------- 7BUID
-		rATQA[0] = 0x44;
 
+	} else if (flags & FLAG_7B_UID_IN_DATA) {
+		// 7B uid comes from data-portion of packet
+		memcpy(&rUIDBCC1[1],datain,3);
+		memcpy(rUIDBCC2, datain+3, 4);
+		_7BUID = true;
+	} else {
+		// get UID from emul memory
+		emlGetMemBt(receivedCmd, 7, 1);
+		_7BUID = !(receivedCmd[0] == 0x00);
+		if (!_7BUID) {                     // ---------- 4BUID
+			emlGetMemBt(rUIDBCC1, 0, 4);
+		} else {                           // ---------- 7BUID
+			emlGetMemBt(&rUIDBCC1[1], 0, 3);
+			emlGetMemBt(rUIDBCC2, 3, 4);
+		}
+	}
+
+	/*
+	 * Regardless of what method was used to set the UID, set fifth byte and modify
+	 * the ATQA for 4 or 7-byte UID
+	 */
+	rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
+	if (_7BUID) {
+		rATQA[0] = 0x44;
 		rUIDBCC1[0] = 0x88;
-		emlGetMemBt(&rUIDBCC1[1], 0, 3);
-		rUIDBCC1[4] = rUIDBCC1[0] ^ rUIDBCC1[1] ^ rUIDBCC1[2] ^ rUIDBCC1[3];
-		emlGetMemBt(rUIDBCC2, 3, 4);
 		rUIDBCC2[4] = rUIDBCC2[0] ^ rUIDBCC2[1] ^ rUIDBCC2[2] ^ rUIDBCC2[3];
 	}
 
-// --------------------------------------	test area
-
-// --------------------------------------	END test area
-	// start mkseconds counter
-	StartCountUS();
-
 	// We need to listen to the high-frequency, peak-detected path.
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-	FpgaSetupSsc();
-
-  FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_LISTEN);
-	SpinDelay(200);
+	iso14443a_setup(FPGA_HF_ISO14443A_TAGSIM_LISTEN);
 
-	if (MF_DBGLEVEL >= 1)	Dbprintf("Started. 7buid=%d", _7BUID);
-	// calibrate mkseconds counter
-	GetDeltaCountUS();
-	while (true) {
-		WDT_HIT();
 
-		if(BUTTON_PRESS()) {
-			break;
+	if (MF_DBGLEVEL >= 1)	{
+		if (!_7BUID) {
+			Dbprintf("4B UID: %02x%02x%02x%02x",rUIDBCC1[0] , rUIDBCC1[1] , rUIDBCC1[2] , rUIDBCC1[3]);
+		} else {
+			Dbprintf("7B UID: (%02x)%02x%02x%02x%02x%02x%02x%02x",rUIDBCC1[0] , rUIDBCC1[1] , rUIDBCC1[2] , rUIDBCC1[3],rUIDBCC2[0],rUIDBCC2[1] ,rUIDBCC2[2] , rUIDBCC2[3]);
 		}
+	}
+
+	bool finished = FALSE;
+	while (!BUTTON_PRESS() && !finished) {
+		WDT_HIT();
 
 		// find reader field
 		// Vref = 3300mV, and an 10:1 voltage divider on the input
@@ -2019,61 +2226,57 @@ void Mifare1ksim(uint8_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
 				LED_A_ON();
 			}
 		} 
+		if(cardSTATE == MFEMUL_NOFIELD) continue;
 
-		if (cardSTATE != MFEMUL_NOFIELD) {
-			res = EmGetCmd(receivedCmd, &len, RECV_CMD_SIZE); // (+ nextCycleTimeout)
-			if (res == 2) {
-				cardSTATE = MFEMUL_NOFIELD;
-				LEDsoff();
-				continue;
-			}
-			if(res) break;
+		//Now, get data
+
+		res = EmGetCmd(receivedCmd, &len);
+		if (res == 2) { //Field is off!
+			cardSTATE = MFEMUL_NOFIELD;
+			LEDsoff();
+			continue;
+		} else if (res == 1) {
+			break; 	//return value 1 means button press
 		}
-		
-		//nextCycleTimeout = 0;
-		
-//		if (len) Dbprintf("len:%d cmd: %02x %02x %02x %02x", len, receivedCmd[0], receivedCmd[1], receivedCmd[2], receivedCmd[3]);
-
-		if (len != 4 && cardSTATE != MFEMUL_NOFIELD) { // len != 4 <---- speed up the code 4 authentication
-			// REQ or WUP request in ANY state and WUP in HALTED state
-			if (len == 1 && ((receivedCmd[0] == 0x26 && cardSTATE != MFEMUL_HALTED) || receivedCmd[0] == 0x52)) {
-				selTimer = GetTickCount();
-				EmSendCmdEx(rATQA, sizeof(rATQA), (receivedCmd[0] == 0x52));
-				cardSTATE = MFEMUL_SELECT1;
-
-				// init crypto block
-				LED_B_OFF();
-				LED_C_OFF();
-				crypto1_destroy(pcs);
-				cardAUTHKEY = 0xff;
-			}
+			
+		// REQ or WUP request in ANY state and WUP in HALTED state
+		if (len == 1 && ((receivedCmd[0] == 0x26 && cardSTATE != MFEMUL_HALTED) || receivedCmd[0] == 0x52)) {
+			selTimer = GetTickCount();
+			EmSendCmdEx(rATQA, sizeof(rATQA), (receivedCmd[0] == 0x52));
+			cardSTATE = MFEMUL_SELECT1;
+
+			// init crypto block
+			LED_B_OFF();
+			LED_C_OFF();
+			crypto1_destroy(pcs);
+			cardAUTHKEY = 0xff;
+			continue;
 		}
 		
 		switch (cardSTATE) {
-			case MFEMUL_NOFIELD:{
-				break;
-			}
-			case MFEMUL_HALTED:{
-				break;
-			}
+			case MFEMUL_NOFIELD:
+			case MFEMUL_HALTED:
 			case MFEMUL_IDLE:{
+				LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+				LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
 				break;
 			}
 			case MFEMUL_SELECT1:{
 				// select all
 				if (len == 2 && (receivedCmd[0] == 0x93 && receivedCmd[1] == 0x20)) {
+					if (MF_DBGLEVEL >= 4)	Dbprintf("SELECT ALL received");
 					EmSendCmd(rUIDBCC1, sizeof(rUIDBCC1));
 					break;
 				}
 
+				if (MF_DBGLEVEL >= 4 && len == 9 && receivedCmd[0] == 0x93 && receivedCmd[1] == 0x70 )
+				{
+					Dbprintf("SELECT %02x%02x%02x%02x received",receivedCmd[2],receivedCmd[3],receivedCmd[4],receivedCmd[5]);
+				}
 				// select card
 				if (len == 9 && 
 						(receivedCmd[0] == 0x93 && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC1, 4) == 0)) {
-					if (!_7BUID) 
-						EmSendCmd(rSAK, sizeof(rSAK));
-					else
-						EmSendCmd(rSAK1, sizeof(rSAK1));
-
+					EmSendCmd(_7BUID?rSAK1:rSAK, sizeof(_7BUID?rSAK1:rSAK));
 					cuid = bytes_to_num(rUIDBCC1, 4);
 					if (!_7BUID) {
 						cardSTATE = MFEMUL_WORK;
@@ -2082,15 +2285,65 @@ void Mifare1ksim(uint8_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
 						break;
 					} else {
 						cardSTATE = MFEMUL_SELECT2;
-						break;
 					}
 				}
-				
+				break;
+			}
+			case MFEMUL_AUTH1:{
+				if( len != 8)
+				{
+					cardSTATE_TO_IDLE();
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					break;
+				}
+				uint32_t ar = bytes_to_num(receivedCmd, 4);
+				uint32_t nr= bytes_to_num(&receivedCmd[4], 4);
+
+				//Collect AR/NR
+				if(ar_nr_collected < 2){
+					if(ar_nr_responses[2] != ar)
+					{// Avoid duplicates... probably not necessary, ar should vary. 
+						ar_nr_responses[ar_nr_collected*4] = cuid;
+						ar_nr_responses[ar_nr_collected*4+1] = nonce;
+						ar_nr_responses[ar_nr_collected*4+2] = ar;
+						ar_nr_responses[ar_nr_collected*4+3] = nr;
+						ar_nr_collected++;
+					}
+				}
+
+				// --- crypto
+				crypto1_word(pcs, ar , 1);
+				cardRr = nr ^ crypto1_word(pcs, 0, 0);
+
+				// test if auth OK
+				if (cardRr != prng_successor(nonce, 64)){
+					if (MF_DBGLEVEL >= 2)	Dbprintf("AUTH FAILED. cardRr=%08x, succ=%08x",cardRr, prng_successor(nonce, 64));
+					// Shouldn't we respond anything here?
+					// Right now, we don't nack or anything, which causes the
+					// reader to do a WUPA after a while. /Martin
+					cardSTATE_TO_IDLE();
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					break;
+				}
+
+				ans = prng_successor(nonce, 96) ^ crypto1_word(pcs, 0, 0);
+
+				num_to_bytes(ans, 4, rAUTH_AT);
+				// --- crypto
+				EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
+				LED_C_ON();
+				cardSTATE = MFEMUL_WORK;
+				if (MF_DBGLEVEL >= 4)	Dbprintf("AUTH COMPLETED. sector=%d, key=%d time=%d", cardAUTHSC, cardAUTHKEY, GetTickCount() - authTimer);
 				break;
 			}
 			case MFEMUL_SELECT2:{
-				if (!len) break;
-			
+				if (!len) { 
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					break;
+				}
 				if (len == 2 && (receivedCmd[0] == 0x95 && receivedCmd[1] == 0x20)) {
 					EmSendCmd(rUIDBCC2, sizeof(rUIDBCC2));
 					break;
@@ -2100,7 +2353,6 @@ void Mifare1ksim(uint8_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
 				if (len == 9 && 
 						(receivedCmd[0] == 0x95 && receivedCmd[1] == 0x70 && memcmp(&receivedCmd[2], rUIDBCC2, 4) == 0)) {
 					EmSendCmd(rSAK, sizeof(rSAK));
-
 					cuid = bytes_to_num(rUIDBCC2, 4);
 					cardSTATE = MFEMUL_WORK;
 					LED_B_ON();
@@ -2109,86 +2361,51 @@ void Mifare1ksim(uint8_t arg0, uint8_t arg1, uint8_t arg2, uint8_t *datain)
 				}
 				
 				// i guess there is a command). go into the work state.
-				if (len != 4) break;
-				cardSTATE = MFEMUL_WORK;
-				goto lbWORK;
-			}
-			case MFEMUL_AUTH1:{
-				if (len == 8) {
-					// --- crypto
-					//rn_enc = bytes_to_num(receivedCmd, 4);
-					//cardRn = rn_enc ^ crypto1_word(pcs, rn_enc , 1);
-					cardRr = bytes_to_num(&receivedCmd[4], 4) ^ crypto1_word(pcs, 0, 0);
-					// test if auth OK
-					if (cardRr != prng_successor(nonce, 64)){
-						if (MF_DBGLEVEL >= 4)	Dbprintf("AUTH FAILED. cardRr=%08x, succ=%08x", cardRr, prng_successor(nonce, 64));
-						cardSTATE_TO_IDLE();
-						break;
-					}
-					ans = prng_successor(nonce, 96) ^ crypto1_word(pcs, 0, 0);
-					num_to_bytes(ans, 4, rAUTH_AT);
-					// --- crypto
-					EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
-					cardSTATE = MFEMUL_AUTH2;
-				} else {
-					cardSTATE_TO_IDLE();
+				if (len != 4) {
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					break;
 				}
-				if (cardSTATE != MFEMUL_AUTH2) break;
-			}
-			case MFEMUL_AUTH2:{
-				LED_C_ON();
 				cardSTATE = MFEMUL_WORK;
-				if (MF_DBGLEVEL >= 4)	Dbprintf("AUTH COMPLETED. sec=%d, key=%d time=%d", cardAUTHSC, cardAUTHKEY, GetTickCount() - authTimer);
-				break;
+				//goto lbWORK;
+				//intentional fall-through to the next case-stmt
 			}
+
 			case MFEMUL_WORK:{
-lbWORK:	if (len == 0) break;
+				if (len == 0) {
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					break;
+				}
 				
-				if (cardAUTHKEY == 0xff) {
-					// first authentication
-					if (len == 4 && (receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61)) {
-						authTimer = GetTickCount();
-
-						cardAUTHSC = receivedCmd[1] / 4;  // received block num
-						cardAUTHKEY = receivedCmd[0] - 0x60;
+				bool encrypted_data = (cardAUTHKEY != 0xFF) ;
 
-						// --- crypto
-						crypto1_create(pcs, emlGetKey(cardAUTHSC, cardAUTHKEY));
-						ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0); 
-						num_to_bytes(nonce, 4, rAUTH_AT);
-						EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
-						// --- crypto
-						
-//   last working revision 
-//						EmSendCmd14443aRaw(resp1, resp1Len, 0);
-//						LogTrace(NULL, 0, GetDeltaCountUS(), 0, true);
-
-						cardSTATE = MFEMUL_AUTH1;
-						//nextCycleTimeout = 10;
-						break;
-					}
-				} else {
+				if(encrypted_data) {
 					// decrypt seqence
 					mf_crypto1_decrypt(pcs, receivedCmd, len);
-					
-					// nested authentication
-					if (len == 4 && (receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61)) {
-						authTimer = GetTickCount();
-
-						cardAUTHSC = receivedCmd[1] / 4;  // received block num
-						cardAUTHKEY = receivedCmd[0] - 0x60;
-
-						// --- crypto
-						crypto1_create(pcs, emlGetKey(cardAUTHSC, cardAUTHKEY));
+				}
+				
+				if (len == 4 && (receivedCmd[0] == 0x60 || receivedCmd[0] == 0x61)) {
+					authTimer = GetTickCount();
+					cardAUTHSC = receivedCmd[1] / 4;  // received block num
+					cardAUTHKEY = receivedCmd[0] - 0x60;
+					crypto1_destroy(pcs);//Added by martin
+					crypto1_create(pcs, emlGetKey(cardAUTHSC, cardAUTHKEY));
+
+					if (!encrypted_data) { // first authentication
+						if (MF_DBGLEVEL >= 2) Dbprintf("Reader authenticating for block %d (0x%02x) with key %d",receivedCmd[1] ,receivedCmd[1],cardAUTHKEY  );
+
+						crypto1_word(pcs, cuid ^ nonce, 0);//Update crypto state
+						num_to_bytes(nonce, 4, rAUTH_AT); // Send nonce
+					} else { // nested authentication
+						if (MF_DBGLEVEL >= 2) Dbprintf("Reader doing nested authentication for block %d (0x%02x) with key %d",receivedCmd[1] ,receivedCmd[1],cardAUTHKEY );
 						ans = nonce ^ crypto1_word(pcs, cuid ^ nonce, 0); 
 						num_to_bytes(ans, 4, rAUTH_AT);
-						EmSendCmd(rAUTH_AT, sizeof(rAUTH_AT));
-						// --- crypto
-
-						cardSTATE = MFEMUL_AUTH1;
-						//nextCycleTimeout = 10;
-						break;
 					}
+					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;
+					break;
 				}
 				
 				// rule 13 of 7.5.3. in ISO 14443-4. chaining shall be continued
@@ -2204,39 +2421,59 @@ lbWORK:	if (len == 0) break;
 					break;
 				}
 				
-				// read block
-				if (len == 4 && receivedCmd[0] == 0x30) {
-					if (receivedCmd[1] >= 16 * 4 || receivedCmd[1] / 4 != cardAUTHSC) {
+				if(len != 4) {
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
+					break;
+				}
+
+				if(receivedCmd[0] == 0x30 // read block
+						|| receivedCmd[0] == 0xA0 // write block
+						|| receivedCmd[0] == 0xC0
+						|| receivedCmd[0] == 0xC1
+						|| receivedCmd[0] == 0xC2 // inc dec restore
+						|| 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]);
+						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);
 						break;
 					}
+				}
+				// read block
+				if (receivedCmd[0] == 0x30) {
+					if (MF_DBGLEVEL >= 2) {
+						Dbprintf("Reader reading block %d (0x%02x)",receivedCmd[1],receivedCmd[1]);
+					}
 					emlGetMem(response, receivedCmd[1], 1);
 					AppendCrc14443a(response, 16);
 					mf_crypto1_encrypt(pcs, response, 18, &par);
 					EmSendCmdPar(response, 18, par);
+					numReads++;
+					if(exitAfterNReads > 0 && numReads == exitAfterNReads) {
+						Dbprintf("%d reads done, exiting", numReads);
+						finished = true;
+					}
 					break;
 				}
-				
 				// write block
-				if (len == 4 && receivedCmd[0] == 0xA0) {
-					if (receivedCmd[1] >= 16 * 4 || receivedCmd[1] / 4 != cardAUTHSC) {
-						EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
-						break;
-					}
+				if (receivedCmd[0] == 0xA0) {
+					if (MF_DBGLEVEL >= 2) Dbprintf("RECV 0xA0 write block %d (%02x)",receivedCmd[1],receivedCmd[1]);
 					EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
-					//nextCycleTimeout = 50;
 					cardSTATE = MFEMUL_WRITEBL2;
 					cardWRBL = receivedCmd[1];
 					break;
 				}
-			
-				// works with cardINTREG
-				
 				// increment, decrement, restore
-				if (len == 4 && (receivedCmd[0] == 0xC0 || receivedCmd[0] == 0xC1 || receivedCmd[0] == 0xC2)) {
-					if (receivedCmd[1] >= 16 * 4 || 
-							receivedCmd[1] / 4 != cardAUTHSC || 
-							emlCheckValBl(receivedCmd[1])) {
+				if (receivedCmd[0] == 0xC0 || receivedCmd[0] == 0xC1 || receivedCmd[0] == 0xC2) {
+					if (MF_DBGLEVEL >= 2) Dbprintf("RECV 0x%02x inc(0xC1)/dec(0xC0)/restore(0xC2) block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
+					if (emlCheckValBl(receivedCmd[1])) {
+						if (MF_DBGLEVEL >= 2) Dbprintf("Reader tried to operate on block, but emlCheckValBl failed, nacking");
 						EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
 						break;
 					}
@@ -2248,42 +2485,35 @@ lbWORK:	if (len == 0) break;
 					if (receivedCmd[0] == 0xC2)
 						cardSTATE = MFEMUL_INTREG_REST;
 					cardWRBL = receivedCmd[1];
-					
 					break;
 				}
-				
-
 				// transfer
-				if (len == 4 && receivedCmd[0] == 0xB0) {
-					if (receivedCmd[1] >= 16 * 4 || receivedCmd[1] / 4 != cardAUTHSC) {
-						EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
-						break;
-					}
-					
+				if (receivedCmd[0] == 0xB0) {
+					if (MF_DBGLEVEL >= 2) Dbprintf("RECV 0x%02x transfer block %d (%02x)",receivedCmd[0],receivedCmd[1],receivedCmd[1]);
 					if (emlSetValBl(cardINTREG, cardINTBLOCK, receivedCmd[1]))
 						EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
 					else
 						EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
-						
 					break;
 				}
-
 				// halt
-				if (len == 4 && (receivedCmd[0] == 0x50 && receivedCmd[1] == 0x00)) {
+				if (receivedCmd[0] == 0x50 && receivedCmd[1] == 0x00) {
 					LED_B_OFF();
 					LED_C_OFF();
 					cardSTATE = MFEMUL_HALTED;
 					if (MF_DBGLEVEL >= 4)	Dbprintf("--> HALTED. Selected time: %d ms",  GetTickCount() - selTimer);
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
 					break;
 				}
-				
-				// command not allowed
-				if (len == 4) {
+				// RATS
+				if (receivedCmd[0] == 0xe0) {//RATS
 					EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
 					break;
 				}
-
-				// case break
+				// command not allowed
+				if (MF_DBGLEVEL >= 4)	Dbprintf("Received command not allowed, nacking");
+				EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
 				break;
 			}
 			case MFEMUL_WRITEBL2:{
@@ -2292,10 +2522,10 @@ lbWORK:	if (len == 0) break;
 					emlSetMem(receivedCmd, cardWRBL, 1);
 					EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_ACK));
 					cardSTATE = MFEMUL_WORK;
-					break;
 				} else {
 					cardSTATE_TO_IDLE();
-					break;
+					LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+					LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
 				}
 				break;
 			}
@@ -2307,7 +2537,9 @@ lbWORK:	if (len == 0) break;
 					EmSend4bit(mf_crypto1_encrypt4bit(pcs, CARD_NACK_NA));
 					cardSTATE_TO_IDLE();
 					break;
-				}
+				} 
+				LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+				LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
 				cardINTREG = cardINTREG + ans;
 				cardSTATE = MFEMUL_WORK;
 				break;
@@ -2320,6 +2552,8 @@ lbWORK:	if (len == 0) break;
 					cardSTATE_TO_IDLE();
 					break;
 				}
+				LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+				LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
 				cardINTREG = cardINTREG - ans;
 				cardSTATE = MFEMUL_WORK;
 				break;
@@ -2332,6 +2566,8 @@ lbWORK:	if (len == 0) break;
 					cardSTATE_TO_IDLE();
 					break;
 				}
+				LogTrace(Uart.output, Uart.len, Uart.startTime*16 - DELAY_AIR2ARM_AS_TAG, Uart.parityBits, TRUE);
+				LogTrace(NULL, 0, Uart.endTime*16 - DELAY_AIR2ARM_AS_TAG, 0, TRUE);
 				cardSTATE = MFEMUL_WORK;
 				break;
 			}
@@ -2341,13 +2577,41 @@ lbWORK:	if (len == 0) break;
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 	LEDsoff();
 
-	// add trace trailer
-	memset(rAUTH_NT, 0x44, 4);
-	LogTrace(rAUTH_NT, 4, 0, 0, TRUE);
+	if(flags & FLAG_INTERACTIVE)// Interactive mode flag, means we need to send ACK
+	{
+		//May just aswell send the collected ar_nr in the response aswell
+		cmd_send(CMD_ACK,CMD_SIMULATE_MIFARE_CARD,0,0,&ar_nr_responses,ar_nr_collected*4*4);
+	}
 
+	if(flags & FLAG_NR_AR_ATTACK)
+	{
+		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[1], //NT
+					ar_nr_responses[2], //AR1
+					ar_nr_responses[3], //NR1
+					ar_nr_responses[6], //AR2
+					ar_nr_responses[7] //NR2
+					);
+		} else {
+			Dbprintf("Failed to obtain two AR/NR pairs!");
+			if(ar_nr_collected >0) {
+				Dbprintf("Only got these: UID=%08x, nonce=%08x, AR1=%08x, NR1=%08x",
+						ar_nr_responses[0], // UID
+						ar_nr_responses[1], //NT
+						ar_nr_responses[2], //AR1
+						ar_nr_responses[3] //NR1
+						);
+			}
+		}
+	}
 	if (MF_DBGLEVEL >= 1)	Dbprintf("Emulator stopped. Tracing: %d  trace length: %d ",	tracing, traceLen);
 }
 
+
+
 //-----------------------------------------------------------------------------
 // MIFARE sniffer. 
 // 
@@ -2356,11 +2620,11 @@ void RAMFUNC SniffMifare(uint8_t param) {
 	// param:
 	// bit 0 - trigger from first card answer
 	// bit 1 - trigger from first reader 7-bit request
-	
+
+	// C(red) A(yellow) B(green)
 	LEDsoff();
 	// init trace buffer
-	traceLen = 0;
-	memset(trace, 0x44, TRACE_SIZE);
+    iso14a_clear_trace();
 
 	// The command (reader -> tag) that we're receiving.
 	// The length of a received command will in most cases be no more than 18 bytes.
@@ -2374,68 +2638,77 @@ void RAMFUNC SniffMifare(uint8_t param) {
 	//uint8_t *trace = (uint8_t *)BigBuf;
 	
 	// The DMA buffer, used to stream samples from the FPGA
-	int8_t *dmaBuf = ((int8_t *)BigBuf) + DMA_BUFFER_OFFSET;
-	int8_t *data = dmaBuf;
+	uint8_t *dmaBuf = ((uint8_t *)BigBuf) + DMA_BUFFER_OFFSET;
+	uint8_t *data = dmaBuf;
+	uint8_t previous_data = 0;
 	int maxDataLen = 0;
 	int dataLen = 0;
-//	data = dmaBuf;
+	bool ReaderIsActive = FALSE;
+	bool TagIsActive = FALSE;
+
+	iso14443a_setup(FPGA_HF_ISO14443A_SNIFFER);
 
 	// Set up the demodulator for tag -> reader responses.
 	Demod.output = receivedResponse;
-	Demod.len = 0;
-	Demod.state = DEMOD_UNSYNCD;
 
 	// Set up the demodulator for the reader -> tag commands
-	memset(&Uart, 0, sizeof(Uart));
 	Uart.output = receivedCmd;
-	Uart.byteCntMax = 32; // was 100 (greg)//////////////////
-	Uart.state = STATE_UNSYNCD;
 
 	// Setup for the DMA.
-	FpgaSetupSsc();
-	FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE);
+	FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
 
-	// And put the FPGA in the appropriate mode
-	// Signal field is off with the appropriate LED
 	LED_D_OFF();
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_SNIFFER);
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+	
+	// init sniffer
+	MfSniffInit();
 
-	// Count of samples received so far, so that we can include timing
-	// information in the trace buffer.
-	rsamples = 0;
 	// And now we loop, receiving samples.
-	while(true) {
+	for(uint32_t sniffCounter = 0; TRUE; ) {
+	
 		if(BUTTON_PRESS()) {
 			DbpString("cancelled by button");
-			goto done;
+			break;
 		}
 
 		LED_A_ON();
 		WDT_HIT();
-
-		int register readBufDataP = data - dmaBuf;
-		int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR;
-		if (readBufDataP <= dmaBufDataP){
-			dataLen = dmaBufDataP - readBufDataP;
-		} else {
-			dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP + 1;
+		
+ 		if ((sniffCounter & 0x0000FFFF) == 0) {	// from time to time
+			// check if a transaction is completed (timeout after 2000ms).
+			// if yes, stop the DMA transfer and send what we have so far to the client
+			if (MfSniffSend(2000)) {			
+				// Reset everything - we missed some sniffed data anyway while the DMA was stopped
+				sniffCounter = 0;
+				data = dmaBuf;
+				maxDataLen = 0;
+				ReaderIsActive = FALSE;
+				TagIsActive = FALSE;
+				FpgaSetupSscDma((uint8_t *)dmaBuf, DMA_BUFFER_SIZE); // set transfer address and number of bytes. Start transfer.
+			}
+		}
+		
+		int register readBufDataP = data - dmaBuf;	// number of bytes we have processed so far
+		int register dmaBufDataP = DMA_BUFFER_SIZE - AT91C_BASE_PDC_SSC->PDC_RCR; // number of bytes already transferred
+		if (readBufDataP <= dmaBufDataP){			// we are processing the same block of data which is currently being transferred
+			dataLen = dmaBufDataP - readBufDataP;	// number of bytes still to be processed
+		} else {									
+			dataLen = DMA_BUFFER_SIZE - readBufDataP + dmaBufDataP; // number of bytes still to be processed
 		}
 		// test for length of buffer
-		if(dataLen > maxDataLen) {
-			maxDataLen = dataLen;
+		if(dataLen > maxDataLen) {					// we are more behind than ever...
+			maxDataLen = dataLen;					
 			if(dataLen > 400) {
 				Dbprintf("blew circular buffer! dataLen=0x%x", dataLen);
-				goto done;
+				break;
 			}
 		}
 		if(dataLen < 1) continue;
 
-		// primary buffer was stopped( <-- we lost data!
+		// primary buffer was stopped ( <-- we lost data!
 		if (!AT91C_BASE_PDC_SSC->PDC_RCR) {
 			AT91C_BASE_PDC_SSC->PDC_RPR = (uint32_t) dmaBuf;
 			AT91C_BASE_PDC_SSC->PDC_RCR = DMA_BUFFER_SIZE;
-			Dbprintf("RxEmpty ERROR!!! %d", dataLen); // temporary
+			Dbprintf("RxEmpty ERROR!!! data length:%d", dataLen); // temporary
 		}
 		// secondary buffer sets as primary, secondary buffer was stopped
 		if (!AT91C_BASE_PDC_SSC->PDC_RNCR) {
@@ -2445,46 +2718,51 @@ void RAMFUNC SniffMifare(uint8_t param) {
 
 		LED_A_OFF();
 		
-		rsamples += 4;
-		if(MillerDecoding((data[0] & 0xF0) >> 4)) {
-			LED_C_ON();
-			// check - if there is a short 7bit request from reader
-			if ((Uart.byteCnt == 1) && (Uart.bitCnt = 9)) { 
-
-			}
-			if (!LogTrace(receivedCmd, Uart.byteCnt, 0 - Uart.samples, Uart.parityBits, TRUE)) break;
+		if (sniffCounter & 0x01) {
 
-			/* And ready to receive another command. */
-			Uart.state = STATE_UNSYNCD;
-			/* And also reset the demod code, which might have been */
-			/* false-triggered by the commands from the reader. */
-			Demod.state = DEMOD_UNSYNCD;
-			LED_B_OFF();
-		}
+			if(!TagIsActive) {		// no need to try decoding tag data if the reader is sending
+				uint8_t readerdata = (previous_data & 0xF0) | (*data >> 4);
+				if(MillerDecoding(readerdata, (sniffCounter-1)*4)) {
+					LED_C_INV();
+					if (MfSniffLogic(receivedCmd, Uart.len, Uart.parityBits, Uart.bitCount, TRUE)) break;
 
-		if(ManchesterDecoding(data[0] & 0x0F)) {
-			LED_B_ON();
+					/* And ready to receive another command. */
+					UartReset();
+					
+					/* And also reset the demod code */
+					DemodReset();
+				}
+				ReaderIsActive = (Uart.state != STATE_UNSYNCD);
+			}
+			
+			if(!ReaderIsActive) {		// no need to try decoding tag data if the reader is sending
+				uint8_t tagdata = (previous_data << 4) | (*data & 0x0F);
+				if(ManchesterDecoding(tagdata, 0, (sniffCounter-1)*4)) {
+					LED_C_INV();
 
-			if (!LogTrace(receivedResponse, Demod.len, 0 - Demod.samples, Demod.parityBits, FALSE)) break;
+					if (MfSniffLogic(receivedResponse, Demod.len, Demod.parityBits, Demod.bitCount, FALSE)) break;
 
-			// And ready to receive another response.
-			memset(&Demod, 0, sizeof(Demod));
-			Demod.output = receivedResponse;
-			Demod.state = DEMOD_UNSYNCD;
-			LED_C_OFF();
+					// And ready to receive another response.
+					DemodReset();
+				}
+				TagIsActive = (Demod.state != DEMOD_UNSYNCD);
+			}
 		}
 
+		previous_data = *data;
+		sniffCounter++;
 		data++;
-		if(data > dmaBuf + DMA_BUFFER_SIZE) {
+		if(data == dmaBuf + DMA_BUFFER_SIZE) {
 			data = dmaBuf;
 		}
+
 	} // main cycle
 
 	DbpString("COMMAND FINISHED");
 
-done:
-	AT91C_BASE_PDC_SSC->PDC_PTCR = AT91C_PDC_RXTDIS;
-	Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.byteCnt=%x", maxDataLen, Uart.state, Uart.byteCnt);
-	Dbprintf("Uart.byteCntMax=%x, traceLen=%x, Uart.output[0]=%x", Uart.byteCntMax, traceLen, (int)Uart.output[0]);
+	FpgaDisableSscDma();
+	MfSniffEnd();
+	
+	Dbprintf("maxDataLen=%x, Uart.state=%x, Uart.len=%x", maxDataLen, Uart.state, Uart.len);
 	LEDsoff();
-}
\ No newline at end of file
+}