X-Git-Url: http://cvs.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/51d4f6f1146b083f12381419bbfb6addd550e6a3..09ffd16ee2d0d6d43fc562035487226cf4f58b86:/armsrc/iso14443b.c

diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
index f598df3c..33c047d8 100644
--- a/armsrc/iso14443b.c
+++ b/armsrc/iso14443b.c
@@ -17,7 +17,7 @@
 #include "iso14443crc.h"
 
 #define RECEIVE_SAMPLES_TIMEOUT 2000
-#define ISO14443B_DMA_BUFFER_SIZE 512
+#define ISO14443B_DMA_BUFFER_SIZE 256
 
 //=============================================================================
 // An ISO 14443 Type B tag. We listen for commands from the reader, using
@@ -123,8 +123,7 @@ static struct {
 		STATE_UNSYNCD,
 		STATE_GOT_FALLING_EDGE_OF_SOF,
 		STATE_AWAITING_START_BIT,
-		STATE_RECEIVING_DATA,
-		STATE_ERROR_WAIT
+		STATE_RECEIVING_DATA
 	}       state;
 	uint16_t    shiftReg;
 	int     bitCnt;
@@ -146,7 +145,7 @@ static struct {
  * Returns: true if we received a EOF
  *          false if we are still waiting for some more
  */
-static int Handle14443bUartBit(int bit)
+static RAMFUNC int Handle14443bUartBit(uint8_t bit)
 {
 	switch(Uart.state) {
 		case STATE_UNSYNCD:
@@ -173,7 +172,7 @@ static int Handle14443bUartBit(int bit)
 					} else {
 						// didn't stay down long enough
 						// before going high, error
-						Uart.state = STATE_ERROR_WAIT;
+						Uart.state = STATE_UNSYNCD;
 					}
 				} else {
 					// do nothing, keep waiting
@@ -184,7 +183,8 @@ static int Handle14443bUartBit(int bit)
 			if(Uart.bitCnt > 12) {
 				// Give up if we see too many zeros without
 				// a one, too.
-				Uart.state = STATE_ERROR_WAIT;
+				LED_A_OFF();
+				Uart.state = STATE_UNSYNCD;
 			}
 			break;
 
@@ -194,7 +194,7 @@ static int Handle14443bUartBit(int bit)
 				if(Uart.posCnt > 50/2) {	// max 57us between characters = 49 1/fs, max 3 etus after low phase of SOF = 24 1/fs
 					// stayed high for too long between
 					// characters, error
-					Uart.state = STATE_ERROR_WAIT;
+					Uart.state = STATE_UNSYNCD;
 				}
 			} else {
 				// falling edge, this starts the data byte
@@ -228,37 +228,30 @@ static int Handle14443bUartBit(int bit)
 
 					if(Uart.byteCnt >= Uart.byteCntMax) {
 						// Buffer overflowed, give up
-						Uart.posCnt = 0;
-						Uart.state = STATE_ERROR_WAIT;
+						LED_A_OFF();
+						Uart.state = STATE_UNSYNCD;
 					} else {
 						// so get the next byte now
 						Uart.posCnt = 0;
 						Uart.state = STATE_AWAITING_START_BIT;
 					}
-				} else if(Uart.shiftReg == 0x000) {
+				} else if (Uart.shiftReg == 0x000) {
 					// this is an EOF byte
 					LED_A_OFF(); // Finished receiving
-					return TRUE;
+					Uart.state = STATE_UNSYNCD;
+					if (Uart.byteCnt != 0) {
+						return TRUE;
+					}
 				} else {
 					// this is an error
-					Uart.posCnt = 0;
-					Uart.state = STATE_ERROR_WAIT;
+					LED_A_OFF();
+					Uart.state = STATE_UNSYNCD;
 				}
 			}
 			break;
 
-		case STATE_ERROR_WAIT:
-			// We're all screwed up, so wait a little while
-			// for whatever went wrong to finish, and then
-			// start over.
-			Uart.posCnt++;
-			if(Uart.posCnt > 10) {
-				Uart.state = STATE_UNSYNCD;
-				LED_A_OFF();
-			}
-			break;
-
 		default:
+			LED_A_OFF();
 			Uart.state = STATE_UNSYNCD;
 			break;
 	}
@@ -266,6 +259,23 @@ static int Handle14443bUartBit(int bit)
 	return FALSE;
 }
 
+
+static void UartReset()
+{
+	Uart.byteCntMax = MAX_FRAME_SIZE;
+	Uart.state = STATE_UNSYNCD;
+	Uart.byteCnt = 0;
+	Uart.bitCnt = 0;
+}
+
+
+static void UartInit(uint8_t *data)
+{
+	Uart.output = data;
+	UartReset();
+}
+
+
 //-----------------------------------------------------------------------------
 // Receive a command (from the reader to us, where we are the simulated tag),
 // and store it in the given buffer, up to the given maximum length. Keeps
@@ -275,44 +285,34 @@ static int Handle14443bUartBit(int bit)
 // Assume that we're called with the SSC (to the FPGA) and ADC path set
 // correctly.
 //-----------------------------------------------------------------------------
-static int GetIso14443bCommandFromReader(uint8_t *received, int *len, int maxLen)
+static int GetIso14443bCommandFromReader(uint8_t *received, uint16_t *len)
 {
-	uint8_t mask;
-	int i, bit;
-
 	// Set FPGA mode to "simulated ISO 14443B tag", no modulation (listen
 	// only, since we are receiving, not transmitting).
 	// Signal field is off with the appropriate LED
 	LED_D_OFF();
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
 
-
 	// Now run a `software UART' on the stream of incoming samples.
-	Uart.output = received;
-	Uart.byteCntMax = maxLen;
-	Uart.state = STATE_UNSYNCD;
+	UartInit(received);
 
 	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;
-
-			mask = 0x80;
-			for(i = 0; i < 8; i++, mask >>= 1) {
-				bit = (b & mask);
-				if(Handle14443bUartBit(bit)) {
+			for(uint8_t mask = 0x80; mask != 0x00; mask >>= 1) {
+				if(Handle14443bUartBit(b & mask)) {
 					*len = Uart.byteCnt;
 					return TRUE;
 				}
 			}
 		}
 	}
+	
+	return FALSE;
 }
 
 //-----------------------------------------------------------------------------
@@ -321,9 +321,12 @@ static int GetIso14443bCommandFromReader(uint8_t *received, int *len, int maxLen
 //-----------------------------------------------------------------------------
 void SimulateIso14443bTag(void)
 {
-	// the only command we understand is REQB, AFI=0, Select All, N=0:
+	// the only commands we understand is REQB, AFI=0, Select All, N=0:
 	static const uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };
-	// ... and we respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
+	// ... and REQB, AFI=0, Normal Request, N=0:
+	static const uint8_t cmd2[] = { 0x05, 0x00, 0x00, 0x71, 0xFF };
+
+	// ... and we always respond with ATQB, PUPI = 820de174, Application Data = 0x20381922,
 	// supports only 106kBit/s in both directions, max frame size = 32Bytes,
 	// supports ISO14443-4, FWI=8 (77ms), NAD supported, CID not supported:
 	static const uint8_t response1[] = {
@@ -331,25 +334,27 @@ void SimulateIso14443bTag(void)
 		0x00, 0x21, 0x85, 0x5e, 0xd7
 	};
 
-	uint8_t *resp;
-	int respLen;
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+
+	clear_trace();
+	set_tracing(TRUE);
+
+	const uint8_t *resp;
+	uint8_t *respCode;
+	uint16_t respLen, respCodeLen;
 
 	// allocate command receive buffer
 	BigBuf_free();
 	uint8_t *receivedCmd = BigBuf_malloc(MAX_FRAME_SIZE);
-	int len;
 
-	int i;
-
-	int cmdsRecvd = 0;
-
-	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	uint16_t len;
+	uint16_t cmdsRecvd = 0;
 
 	// prepare the (only one) tag answer:
 	CodeIso14443bAsTag(response1, sizeof(response1));
-	uint8_t *resp1 = BigBuf_malloc(ToSendMax);
-	memcpy(resp1, ToSend, ToSendMax); 
-	uint16_t resp1Len = ToSendMax;
+	uint8_t *resp1Code = BigBuf_malloc(ToSendMax);
+	memcpy(resp1Code, ToSend, ToSendMax); 
+	uint16_t resp1CodeLen = ToSendMax;
 
 	// We need to listen to the high-frequency, peak-detected path.
 	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
@@ -358,20 +363,28 @@ void SimulateIso14443bTag(void)
 	cmdsRecvd = 0;
 
 	for(;;) {
-		uint8_t b1, b2;
 
-		if(!GetIso14443bCommandFromReader(receivedCmd, &len, 100)) {
+		if(!GetIso14443bCommandFromReader(receivedCmd, &len)) {
 			Dbprintf("button pressed, received %d commands", cmdsRecvd);
 			break;
-			}
+		}
 
-		// Good, look at the command now.
+		if (tracing) {
+			uint8_t parity[MAX_PARITY_SIZE];
+			LogTrace(receivedCmd, len, 0, 0, parity, TRUE);
+		}
 
-		if(len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0) {
-			resp = resp1; respLen = resp1Len;
+		// Good, look at the command now.
+		if ( (len == sizeof(cmd1) && memcmp(receivedCmd, cmd1, len) == 0)
+			|| (len == sizeof(cmd2) && memcmp(receivedCmd, cmd2, len) == 0) ) {
+			resp = response1; 
+			respLen = sizeof(response1);
+			respCode = resp1Code; 
+			respCodeLen = resp1CodeLen;
 		} else {
 			Dbprintf("new cmd from reader: len=%d, cmdsRecvd=%d", len, cmdsRecvd);
 			// And print whether the CRC fails, just for good measure
+			uint8_t b1, b2;
 			ComputeCrc14443(CRC_14443_B, receivedCmd, len-2, &b1, &b2);
 			if(b1 != receivedCmd[len-2] || b2 != receivedCmd[len-1]) {
 				// Not so good, try again.
@@ -389,7 +402,7 @@ void SimulateIso14443bTag(void)
 			break;
 		}
 
-		if(respLen <= 0) continue;
+		if(respCodeLen <= 0) continue;
 
 		// Modulate BPSK
 		// Signal field is off with the appropriate LED
@@ -399,15 +412,15 @@ void SimulateIso14443bTag(void)
 		FpgaSetupSsc();
 
 		// Transmit the response.
-		i = 0;
+		uint16_t i = 0;
 		for(;;) {
 			if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-				uint8_t b = resp[i];
+				uint8_t b = respCode[i];
 
 				AT91C_BASE_SSC->SSC_THR = b;
 
 				i++;
-				if(i > respLen) {
+				if(i > respCodeLen) {
 					break;
 				}
 			}
@@ -416,6 +429,13 @@ void SimulateIso14443bTag(void)
 				(void)b;
 			}
 		}
+		
+		// trace the response:
+		if (tracing) {
+			uint8_t parity[MAX_PARITY_SIZE];
+			LogTrace(resp, respLen, 0, 0, parity, FALSE);
+		}
+			
 	}
 }
 
@@ -433,8 +453,7 @@ static struct {
 		DEMOD_AWAITING_FALLING_EDGE_OF_SOF,
 		DEMOD_GOT_FALLING_EDGE_OF_SOF,
 		DEMOD_AWAITING_START_BIT,
-		DEMOD_RECEIVING_DATA,
-		DEMOD_ERROR_WAIT
+		DEMOD_RECEIVING_DATA
 	}       state;
 	int     bitCount;
 	int     posCount;
@@ -681,22 +700,6 @@ static void DemodInit(uint8_t *data)
 }
 
 
-static void UartReset()
-{
-	Uart.byteCntMax = MAX_FRAME_SIZE;
-	Uart.state = STATE_UNSYNCD;
-	Uart.byteCnt = 0;
-	Uart.bitCnt = 0;
-}
-
-
-static void UartInit(uint8_t *data)
-{
-	Uart.output = data;
-	UartReset();
-}
-
-
 /*
  *  Demodulate the samples we received from the tag, also log to tracebuffer
  *  quiet: set to 'TRUE' to disable debug output
@@ -729,7 +732,7 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
 	// Signal field is ON with the appropriate LED:
 	LED_D_ON();
 	// And put the FPGA in the appropriate mode
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
 
 	for(;;) {
 		int behindBy = lastRxCounter - AT91C_BASE_PDC_SSC->PDC_RCR;
@@ -768,7 +771,6 @@ static void GetSamplesFor14443bDemod(int n, bool quiet)
 	//Tracing
 	if (tracing && Demod.len > 0) {
 		uint8_t parity[MAX_PARITY_SIZE];
-		GetParity(Demod.output, Demod.len, parity);
 		LogTrace(Demod.output, Demod.len, 0, 0, parity, FALSE);
 	}
 }
@@ -881,22 +883,6 @@ static void CodeIso14443bAsReader(const uint8_t *cmd, int len)
 }
 
 
-//-----------------------------------------------------------------------------
-// Read an ISO 14443B tag. We send it some set of commands, and record the
-// responses.
-// The command name is misleading, it actually decodes the reponse in HEX
-// into the output buffer (read the result using hexsamples, not hisamples)
-//
-// obsolete function only for test
-//-----------------------------------------------------------------------------
-void AcquireRawAdcSamplesIso14443b(uint32_t parameter)
-{
-	uint8_t cmd1[] = { 0x05, 0x00, 0x08, 0x39, 0x73 };   // REQB with AFI=0, Request All, N=0
-
-	SendRawCommand14443B(sizeof(cmd1),1,1,cmd1);
-}
-
-
 /**
   Convenience function to encode, transmit and trace iso 14443b comms
   **/
@@ -906,7 +892,6 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 	TransmitFor14443b();
 	if (tracing) {
 		uint8_t parity[MAX_PARITY_SIZE];
-		GetParity(cmd, len, parity);
 		LogTrace(cmd,len, 0, 0, parity, TRUE);
 	}
 }
@@ -923,9 +908,6 @@ static void CodeAndTransmit14443bAsReader(const uint8_t *cmd, int len)
 //-----------------------------------------------------------------------------
 void ReadSTMemoryIso14443b(uint32_t dwLast)
 {
-	clear_trace();
-	set_tracing(TRUE);
-
 	uint8_t i = 0x00;
 
 	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
@@ -941,35 +923,32 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
 	// Now give it time to spin up.
 	// Signal field is on with the appropriate LED
 	LED_D_ON();
-	FpgaWriteConfWord(
-		FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ);
 	SpinDelay(200);
 
+	clear_trace();
+	set_tracing(TRUE);
+
 	// First command: wake up the tag using the INITIATE command
 	uint8_t cmd1[] = {0x06, 0x00, 0x97, 0x5b};
-
 	CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
-//    LED_A_ON();
 	GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
 
 	if (Demod.len == 0) {
-	DbpString("No response from tag");
-	return;
+		DbpString("No response from tag");
+		return;
 	} else {
-	Dbprintf("Randomly generated UID from tag (+ 2 byte CRC): %x %x %x",
-		Demod.output[0], Demod.output[1], Demod.output[2]);
+		Dbprintf("Randomly generated Chip ID (+ 2 byte CRC): %02x %02x %02x",
+				Demod.output[0], Demod.output[1], Demod.output[2]);
 	}
+
 	// There is a response, SELECT the uid
 	DbpString("Now SELECT tag:");
 	cmd1[0] = 0x0E; // 0x0E is SELECT
 	cmd1[1] = Demod.output[0];
 	ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
 	CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
-
-//    LED_A_ON();
 	GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
 	if (Demod.len != 3) {
 		Dbprintf("Expected 3 bytes from tag, got %d", Demod.len);
 		return;
@@ -982,18 +961,16 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
 	}
 	// Check response from the tag: should be the same UID as the command we just sent:
 	if (cmd1[1] != Demod.output[0]) {
-		Dbprintf("Bad response to SELECT from Tag, aborting: %x %x", cmd1[1], Demod.output[0]);
+		Dbprintf("Bad response to SELECT from Tag, aborting: %02x %02x", cmd1[1], Demod.output[0]);
 		return;
 	}
+
 	// Tag is now selected,
 	// First get the tag's UID:
 	cmd1[0] = 0x0B;
 	ComputeCrc14443(CRC_14443_B, cmd1, 1 , &cmd1[1], &cmd1[2]);
 	CodeAndTransmit14443bAsReader(cmd1, 3); // Only first three bytes for this one
-
-//    LED_A_ON();
 	GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//    LED_A_OFF();
 	if (Demod.len != 10) {
 		Dbprintf("Expected 10 bytes from tag, got %d", Demod.len);
 		return;
@@ -1001,16 +978,16 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
 	// The check the CRC of the answer (use cmd1 as temporary variable):
 	ComputeCrc14443(CRC_14443_B, Demod.output, 8, &cmd1[2], &cmd1[3]);
 	if(cmd1[2] != Demod.output[8] || cmd1[3] != Demod.output[9]) {
-		Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
-			(cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
+		Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
+				(cmd1[2]<<8)+cmd1[3], (Demod.output[8]<<8)+Demod.output[9]);
 		// Do not return;, let's go on... (we should retry, maybe ?)
 	}
 	Dbprintf("Tag UID (64 bits): %08x %08x",
-		(Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
-		(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
+			(Demod.output[7]<<24) + (Demod.output[6]<<16) + (Demod.output[5]<<8) + Demod.output[4],
+			(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0]);
 
 	// Now loop to read all 16 blocks, address from 0 to last block
-	Dbprintf("Tag memory dump, block 0 to %d",dwLast);
+	Dbprintf("Tag memory dump, block 0 to %d", dwLast);
 	cmd1[0] = 0x08;
 	i = 0x00;
 	dwLast++;
@@ -1022,10 +999,7 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
 		cmd1[1] = i;
 		ComputeCrc14443(CRC_14443_B, cmd1, 2, &cmd1[2], &cmd1[3]);
 		CodeAndTransmit14443bAsReader(cmd1, sizeof(cmd1));
-
-//	    LED_A_ON();
 		GetSamplesFor14443bDemod(RECEIVE_SAMPLES_TIMEOUT, TRUE);
-//	    LED_A_OFF();
 		if (Demod.len != 6) { // Check if we got an answer from the tag
 			DbpString("Expected 6 bytes from tag, got less...");
 			return;
@@ -1033,14 +1007,14 @@ void ReadSTMemoryIso14443b(uint32_t dwLast)
 		// The check the CRC of the answer (use cmd1 as temporary variable):
 		ComputeCrc14443(CRC_14443_B, Demod.output, 4, &cmd1[2], &cmd1[3]);
 		if(cmd1[2] != Demod.output[4] || cmd1[3] != Demod.output[5]) {
-			Dbprintf("CRC Error reading block! - Below: expected, got %x %x",
-				(cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
+			Dbprintf("CRC Error reading block! Expected: %04x got: %04x",
+					(cmd1[2]<<8)+cmd1[3], (Demod.output[4]<<8)+Demod.output[5]);
 			// Do not return;, let's go on... (we should retry, maybe ?)
 		}
 		// Now print out the memory location:
-		Dbprintf("Address=%x, Contents=%x, CRC=%x", i,
-			(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
-			(Demod.output[4]<<8)+Demod.output[5]);
+		Dbprintf("Address=%02x, Contents=%08x, CRC=%04x", i,
+				(Demod.output[3]<<24) + (Demod.output[2]<<16) + (Demod.output[1]<<8) + Demod.output[0],
+				(Demod.output[4]<<8)+Demod.output[5]);
 		if (i == 0xff) {
 			break;
 		}
@@ -1104,7 +1078,7 @@ void RAMFUNC SnoopIso14443b(void)
 	LEDsoff();
 
 	// And put the FPGA in the appropriate mode
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_SNOOP);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_848_KHZ | FPGA_HF_READER_RX_XCORR_SNOOP);
 	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
 	// Setup for the DMA.
@@ -1138,7 +1112,7 @@ void RAMFUNC SnoopIso14443b(void)
 			AT91C_BASE_PDC_SSC->PDC_RNCR = ISO14443B_DMA_BUFFER_SIZE;
 			WDT_HIT();
 			if(behindBy > (9*ISO14443B_DMA_BUFFER_SIZE/10)) { // TODO: understand whether we can increase/decrease as we want or not?
-				Dbprintf("blew circular buffer! behindBy=0x%x", behindBy);
+				Dbprintf("blew circular buffer! behindBy=%d", behindBy);
 				break;
 			}
 			if(!tracing) {
@@ -1156,7 +1130,6 @@ void RAMFUNC SnoopIso14443b(void)
 		if (!TagIsActive) {							// no need to try decoding reader data if the tag is sending
 			if(Handle14443bUartBit(ci & 0x01)) {
 				if(triggered && tracing) {
-					GetParity(Uart.output, Uart.byteCnt, parity);
 					LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);
 				}
 				/* And ready to receive another command. */
@@ -1167,7 +1140,6 @@ void RAMFUNC SnoopIso14443b(void)
 			}
 			if(Handle14443bUartBit(cq & 0x01)) {
 				if(triggered && tracing) {
-					GetParity(Uart.output, Uart.byteCnt, parity);
 					LogTrace(Uart.output, Uart.byteCnt, samples, samples, parity, TRUE);
 				}
 				/* And ready to receive another command. */
@@ -1176,17 +1148,16 @@ void RAMFUNC SnoopIso14443b(void)
 				/* false-triggered by the commands from the reader. */
 				DemodReset();
 			}
-			ReaderIsActive = (Uart.state != STATE_UNSYNCD);
+			ReaderIsActive = (Uart.state > STATE_GOT_FALLING_EDGE_OF_SOF);
 		}
 
 		if(!ReaderIsActive) {						// no need to try decoding tag data if the reader is sending - and we cannot afford the time
-			if(Handle14443bSamplesDemod(ci & 0xFE, cq & 0xFE)) {
+			if(Handle14443bSamplesDemod(ci | 0x01, cq | 0x01)) {
 
 				//Use samples as a time measurement
 				if(tracing)
 				{
 					uint8_t parity[MAX_PARITY_SIZE];
-					GetParity(Demod.output, Demod.len, parity);
 					LogTrace(Demod.output, Demod.len, samples, samples, parity, FALSE);
 				}
 				triggered = TRUE;
@@ -1194,7 +1165,7 @@ void RAMFUNC SnoopIso14443b(void)
 				// And ready to receive another response.
 				DemodReset();
 			}
-			TagIsActive = (Demod.state > DEMOD_PHASE_REF_TRAINING);
+			TagIsActive = (Demod.state > DEMOD_GOT_FALLING_EDGE_OF_SOF);
 		}
 
 	}
@@ -1231,22 +1202,6 @@ void SendRawCommand14443B(uint32_t datalen, uint32_t recv, uint8_t powerfield, u
 
 	set_tracing(TRUE);
 	
-/* 	if(!powerfield) {
-		// Make sure that we start from off, since the tags are stateful;
-		// confusing things will happen if we don't reset them between reads.
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-		LED_D_OFF();
-		SpinDelay(200);
-	}
- */
-
-	// if(!GETBIT(GPIO_LED_D))	{	// if field is off
-		// FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
-		// // Signal field is on with the appropriate LED
-		// LED_D_ON();
-		// SpinDelay(200);
-	// }
-
 	CodeAndTransmit14443bAsReader(data, datalen);
 
 	if(recv) {