From: pwpiwi <pwpiwi@users.noreply.github.com>
Date: Wed, 16 Oct 2019 07:36:37 +0000 (+0200)
Subject: fix 'hf iclass reader'
X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/commitdiff_plain/c41dd5f9f690777eefd08eaeb43db52f599ce38c?hp=b41be3cb11103739d2fa92ced09d1e29f8151b7b

fix 'hf iclass reader'
* code deduplication. Use functions from iso15693.c
* speedup CodeIso15693AsReader()
* invert reader command coding. 0 now means 'unmodulated' ( = field on)
* decode SOF only as a valid tag response in Handle15693SamplesFromTag()
* complete decoding of EOF in Handle15693SamplesFromTag()
* determine and write correct times to trace
* FPGA-change: generate shorter frame signal to allow proper sync in StartCountSspClk()
* modify StartCountSspClk() for 16bit SSC transfers
* whitespace in util.c
* add specific LogTrace_ISO15693() with scaled down duration. Modify cmdhflist.c accordingly.
* allow 'hf 15 raw' with single byte commands
* check for buffer overflow, card timeout and single SOF in 'hf 15 raw'
---

diff --git a/armsrc/iclass.c b/armsrc/iclass.c
index 2533d1f9..392271bd 100644
--- a/armsrc/iclass.c
+++ b/armsrc/iclass.c
@@ -57,14 +57,17 @@
 #include "usb_cdc.h" // for usb_poll_validate_length
 #include "fpgaloader.h"
 
-static int timeout = 4096;
-
 // iCLASS has a slightly different timing compared to ISO15693. According to the picopass data sheet the tag response is expected 330us after
 // the reader command. This is measured from end of reader EOF to first modulation of the tag's SOF which starts with a 56,64us unmodulated period.
 // 330us = 140 ssp_clk cycles @ 423,75kHz when simulating.
 // 56,64us = 24 ssp_clk_cycles
-#define DELAY_ICLASS_VCD_TO_VICC_SIM 140
-#define TAG_SOF_UNMODULATED          24
+#define DELAY_ICLASS_VCD_TO_VICC_SIM     (140 - 24)
+// times in ssp_clk_cycles @ 3,3625MHz when acting as reader
+#define DELAY_ICLASS_VICC_TO_VCD_READER	 DELAY_ISO15693_VICC_TO_VCD_READER
+// times in samples @ 212kHz when acting as reader
+#define ICLASS_READER_TIMEOUT_ACTALL     330 // 1558us, nominal 330us + 7slots*160us = 1450us         
+#define ICLASS_READER_TIMEOUT_OTHERS      80 // 380us, nominal 330us
+
 
 //-----------------------------------------------------------------------------
 // The software UART that receives commands from the reader, and its state
@@ -698,7 +701,7 @@ void RAMFUNC SnoopIClass(void) {
 				//if (!LogTrace(NULL, 0, Uart.endTime*16 - DELAY_READER_AIR2ARM_AS_SNIFFER, 0, true)) break;
 				uint8_t parity[MAX_PARITY_SIZE];
 				GetParity(Uart.output, Uart.byteCnt, parity);
-				LogTrace(Uart.output, Uart.byteCnt, time_start, time_stop, parity, true);
+				LogTrace_ISO15693(Uart.output, Uart.byteCnt, time_start*32, time_stop*32, parity, true);
 
 				/* And ready to receive another command. */
 				Uart.state = STATE_UNSYNCD;
@@ -723,7 +726,7 @@ void RAMFUNC SnoopIClass(void) {
 
 				uint8_t parity[MAX_PARITY_SIZE];
 				GetParity(Demod.output, Demod.len, parity);
-				LogTrace(Demod.output, Demod.len, time_start, time_stop, parity, false);
+				LogTrace_ISO15693(Demod.output, Demod.len, time_start*32, time_stop*32, parity, false);
 
 				// And ready to receive another response.
 				memset(&Demod, 0, sizeof(Demod));
@@ -1230,9 +1233,9 @@ int doIClassSimulation(int simulationMode, uint8_t *reader_mac_buf) {
 		A legit tag has about 273,4us delay between reader EOT and tag SOF.
 		**/
 		if (modulated_response_size > 0) {
-			uint32_t response_time = reader_eof_time + DELAY_ICLASS_VCD_TO_VICC_SIM - TAG_SOF_UNMODULATED - DELAY_ARM_TO_READER_SIM;
+			uint32_t response_time = reader_eof_time + DELAY_ICLASS_VCD_TO_VICC_SIM;
 			TransmitTo15693Reader(modulated_response, modulated_response_size, &response_time, 0, false);
-			LogTrace(trace_data, trace_data_size, response_time + DELAY_ARM_TO_READER_SIM, response_time + (modulated_response_size << 6) + DELAY_ARM_TO_READER_SIM, NULL, false);
+			LogTrace_ISO15693(trace_data, trace_data_size, response_time*32, response_time*32 + modulated_response_size/2, NULL, false);
 		}
 
 	}
@@ -1327,214 +1330,22 @@ void SimulateIClass(uint32_t arg0, uint32_t arg1, uint32_t arg2, uint8_t *datain
 
 /// THE READER CODE
 
-//-----------------------------------------------------------------------------
-// Transmit the command (to the tag) that was placed in ToSend[].
-//-----------------------------------------------------------------------------
-static void TransmitIClassCommand(const uint8_t *cmd, int len, int *samples, int *wait) {
-	int c;
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-	AT91C_BASE_SSC->SSC_THR = 0x00;
-	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_ISO14443A);
-
-	if (wait) {
-		if (*wait < 10) *wait = 10;
+static void ReaderTransmitIClass(uint8_t *frame, int len, uint32_t *start_time) {
 
-		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();
-		}
-	}
-
-	uint8_t sendbyte;
-	bool firstpart = true;
-	c = 0;
-	for (;;) {
-		if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+	CodeIso15693AsReader(frame, len);
 
-			// DOUBLE THE SAMPLES!
-			if (firstpart) {
-				sendbyte = (cmd[c] & 0xf0) | (cmd[c] >> 4);
-			} else {
-				sendbyte = (cmd[c] & 0x0f) | (cmd[c] << 4);
-				c++;
-			}
-			if (sendbyte == 0xff) {
-				sendbyte = 0xfe;
-			}
-			AT91C_BASE_SSC->SSC_THR = sendbyte;
-			firstpart = !firstpart;
+	TransmitTo15693Tag(ToSend, ToSendMax, start_time);
 
-			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 && wait) *samples = (c + *wait) << 3;
+	uint32_t end_time = *start_time + 32*(8*ToSendMax-4); // substract the 4 padding bits after EOF
+	LogTrace_ISO15693(frame, len, *start_time*4, end_time*4, NULL, true);
 }
 
 
-//-----------------------------------------------------------------------------
-// Prepare iClass reader command to send to FPGA
-//-----------------------------------------------------------------------------
-void CodeIClassCommand(const uint8_t *cmd, int len) {
-	int i, j, k;
-
-	ToSendReset();
-
-	// Start of Communication: 1 out of 4
-	ToSend[++ToSendMax] = 0xf0;
-	ToSend[++ToSendMax] = 0x00;
-	ToSend[++ToSendMax] = 0x0f;
-	ToSend[++ToSendMax] = 0x00;
-
-	// Modulate the bytes
-	for (i = 0; i < len; i++) {
-		uint8_t b = cmd[i];
-		for (j = 0; j < 4; j++) {
-			for (k = 0; k < 4; k++) {
-				if (k == (b & 3)) {
-					ToSend[++ToSendMax] = 0x0f;
-				} else {
-					ToSend[++ToSendMax] = 0x00;
-				}
-			}
-			b >>= 2;
-		}
-	}
-
-	// End of Communication
-	ToSend[++ToSendMax] = 0x00;
-	ToSend[++ToSendMax] = 0x00;
-	ToSend[++ToSendMax] = 0xf0;
-	ToSend[++ToSendMax] = 0x00;
-
-	// Convert from last character reference to length
-	ToSendMax++;
-}
-
-static void ReaderTransmitIClass(uint8_t *frame, int len) {
-	int wait = 0;
-	int samples = 0;
-
-	// This is tied to other size changes
-	CodeIClassCommand(frame, len);
-
-	// Select the card
-	TransmitIClassCommand(ToSend, ToSendMax, &samples, &wait);
-	if (trigger)
-		LED_A_ON();
-
-	// Store reader command in buffer
-	uint8_t par[MAX_PARITY_SIZE];
-	GetParity(frame, len, par);
-	LogTrace(frame, len, rsamples, rsamples, par, true);
-}
-
-//-----------------------------------------------------------------------------
-// Wait a certain time for tag response
-//  If a response is captured return true
-//  If it takes too long return false
-//-----------------------------------------------------------------------------
-static int GetIClassAnswer(uint8_t *receivedResponse, int maxLen, int *samples, int *elapsed) {
-	//uint8_t *buffer
-	// buffer needs to be 512 bytes
-	int c;
-
-	// Set FPGA mode to "reader listen mode", no modulation (listen
-	// only, since we are receiving, not transmitting).
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_LISTEN);
-
-	// Now get the answer from the card
-	Demod.output = receivedResponse;
-	Demod.len = 0;
-	Demod.state = DEMOD_UNSYNCD;
-
-	uint8_t b;
-	if (elapsed) *elapsed = 0;
-
-	bool skip = false;
-
-	c = 0;
-	for (;;) {
-		WDT_HIT();
-
-		if (BUTTON_PRESS()) return false;
-
-		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 < timeout) {
-				c++;
-			} else {
-				return false;
-			}
-			b = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
-			skip = !skip;
-			if (skip) continue;
-
-			if (ManchesterDecoding(b & 0x0f)) {
-				*samples = c << 3;
-				return  true;
-			}
-		}
-	}
-}
-
-static int ReaderReceiveIClass(uint8_t *receivedAnswer) {
-	int samples = 0;
-	if (!GetIClassAnswer(receivedAnswer, 160, &samples, 0)) {
-		return false;
-	}
-	rsamples += samples;
-	uint8_t parity[MAX_PARITY_SIZE];
-	GetParity(receivedAnswer, Demod.len, parity);
-	LogTrace(receivedAnswer, Demod.len, rsamples, rsamples, parity, false);
-	if (samples == 0) return false;
-	return Demod.len;
-}
-
-static void setupIclassReader() {
-	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-	// Reset trace buffer
-	set_tracing(true);
-	clear_trace();
-
-	// Setup SSC
-	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_ISO14443A);
-	// Start from off (no field generated)
-	// Signal field is off with the appropriate LED
-	LED_D_OFF();
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	SpinDelay(200);
-
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-
-	// Now give it time to spin up.
-	// Signal field is on with the appropriate LED
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-	SpinDelay(200);
-	LED_A_ON();
-
-}
-
-static bool sendCmdGetResponseWithRetries(uint8_t* command, size_t cmdsize, uint8_t* resp, uint8_t expected_size, uint8_t retries) {
+static bool sendCmdGetResponseWithRetries(uint8_t* command, size_t cmdsize, uint8_t* resp, size_t max_resp_size, 
+										  uint8_t expected_size, uint8_t retries, uint32_t start_time, uint32_t *eof_time) {
 	while (retries-- > 0) {
-		ReaderTransmitIClass(command, cmdsize);
-		if (expected_size == ReaderReceiveIClass(resp)) {
+		ReaderTransmitIClass(command, cmdsize, &start_time);
+		if (expected_size == GetIso15693AnswerFromTag(resp, max_resp_size, ICLASS_READER_TIMEOUT_OTHERS, eof_time)) {
 			return true;
 		}
 	}
@@ -1548,12 +1359,11 @@ static bool sendCmdGetResponseWithRetries(uint8_t* command, size_t cmdsize, uint
  *         1 = Got CSN
  *         2 = Got CSN and CC
  */
-static uint8_t handshakeIclassTag_ext(uint8_t *card_data, bool use_credit_key) {
-	static uint8_t act_all[]     = { 0x0a };
-	//static uint8_t identify[]    = { 0x0c };
-	static uint8_t identify[]    = { 0x0c, 0x00, 0x73, 0x33 };
-	static uint8_t select[]      = { 0x81, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
-	static uint8_t readcheck_cc[]= { 0x88, 0x02 };
+static uint8_t handshakeIclassTag_ext(uint8_t *card_data, bool use_credit_key, uint32_t *eof_time) {
+	uint8_t act_all[]      = { 0x0a };
+	uint8_t identify[]     = { 0x0c };
+	uint8_t select[]       = { 0x81, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 };
+	uint8_t readcheck_cc[] = { 0x88, 0x02 };
 	if (use_credit_key)
 		readcheck_cc[0] = 0x18;
 	else
@@ -1562,24 +1372,28 @@ static uint8_t handshakeIclassTag_ext(uint8_t *card_data, bool use_credit_key) {
 	uint8_t resp[ICLASS_BUFFER_SIZE];
 
 	uint8_t read_status = 0;
+	uint32_t start_time = GetCountSspClk();
 
 	// Send act_all
-	ReaderTransmitIClass(act_all, 1);
+	ReaderTransmitIClass(act_all, 1, &start_time);
 	// Card present?
-	if (!ReaderReceiveIClass(resp)) return read_status;//Fail
-
+	if (GetIso15693AnswerFromTag(resp, sizeof(resp), ICLASS_READER_TIMEOUT_ACTALL, eof_time) < 0) return read_status;//Fail
+	
 	//Send Identify
-	ReaderTransmitIClass(identify, 1);
+	start_time = *eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
+	ReaderTransmitIClass(identify, 1, &start_time);
+	// FpgaDisableTracing(); // DEBUGGING
 	//We expect a 10-byte response here, 8 byte anticollision-CSN and 2 byte CRC
-	uint8_t len = ReaderReceiveIClass(resp);
+	uint8_t len = GetIso15693AnswerFromTag(resp, sizeof(resp), ICLASS_READER_TIMEOUT_OTHERS, eof_time);
 	if (len != 10) return read_status;//Fail
 
 	//Copy the Anti-collision CSN to our select-packet
 	memcpy(&select[1], resp, 8);
 	//Select the card
-	ReaderTransmitIClass(select, sizeof(select));
+	start_time = *eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
+	ReaderTransmitIClass(select, sizeof(select), &start_time);
 	//We expect a 10-byte response here, 8 byte CSN and 2 byte CRC
-	len = ReaderReceiveIClass(resp);
+	len = GetIso15693AnswerFromTag(resp, sizeof(resp), ICLASS_READER_TIMEOUT_OTHERS, eof_time);
 	if (len != 10) return read_status;//Fail
 
 	//Success - level 1, we got CSN
@@ -1590,8 +1404,9 @@ static uint8_t handshakeIclassTag_ext(uint8_t *card_data, bool use_credit_key) {
 	read_status = 1;
 
 	// Card selected, now read e-purse (cc) (only 8 bytes no CRC)
-	ReaderTransmitIClass(readcheck_cc, sizeof(readcheck_cc));
-	if (ReaderReceiveIClass(resp) == 8) {
+	start_time = *eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
+	ReaderTransmitIClass(readcheck_cc, sizeof(readcheck_cc), &start_time);
+	if (GetIso15693AnswerFromTag(resp, sizeof(resp), ICLASS_READER_TIMEOUT_OTHERS, eof_time) == 8) {
 		//Save CC (e-purse) in response data
 		memcpy(card_data+8, resp, 8);
 		read_status++;
@@ -1600,8 +1415,8 @@ static uint8_t handshakeIclassTag_ext(uint8_t *card_data, bool use_credit_key) {
 	return read_status;
 }
 
-static uint8_t handshakeIclassTag(uint8_t *card_data) {
-	return handshakeIclassTag_ext(card_data, false);
+static uint8_t handshakeIclassTag(uint8_t *card_data, uint32_t *eof_time) {
+	return handshakeIclassTag_ext(card_data, false, eof_time);
 }
 
 
@@ -1633,8 +1448,13 @@ void ReaderIClass(uint8_t arg0) {
 	uint8_t flagReadAA = arg0 & FLAG_ICLASS_READER_AA;
 
 	set_tracing(true);
-	setupIclassReader();
+	clear_trace();
+	Iso15693InitReader();
 
+	StartCountSspClk();
+	uint32_t start_time = 0;
+	uint32_t eof_time = 0;
+	
 	uint16_t tryCnt = 0;
 	bool userCancelled = BUTTON_PRESS() || usb_poll_validate_length();
 	while (!userCancelled) {
@@ -1649,29 +1469,31 @@ void ReaderIClass(uint8_t arg0) {
 		}
 		WDT_HIT();
 
-		read_status = handshakeIclassTag_ext(card_data, use_credit_key);
+		read_status = handshakeIclassTag_ext(card_data, use_credit_key, &eof_time);
 
 		if (read_status == 0) continue;
 		if (read_status == 1) result_status = FLAG_ICLASS_READER_CSN;
 		if (read_status == 2) result_status = FLAG_ICLASS_READER_CSN | FLAG_ICLASS_READER_CC;
 
+		start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 		// handshakeIclass returns CSN|CC, but the actual block
 		// layout is CSN|CONFIG|CC, so here we reorder the data,
 		// moving CC forward 8 bytes
 		memcpy(card_data+16, card_data+8, 8);
 		//Read block 1, config
 		if (flagReadConfig) {
-			if (sendCmdGetResponseWithRetries(readConf, sizeof(readConf), resp, 10, 10)) {
+			if (sendCmdGetResponseWithRetries(readConf, sizeof(readConf), resp, sizeof(resp), 10, 10, start_time, &eof_time)) {
 				result_status |= FLAG_ICLASS_READER_CONF;
 				memcpy(card_data+8, resp, 8);
 			} else {
 				Dbprintf("Failed to dump config block");
 			}
+			start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 		}
 
 		//Read block 5, AA
 		if (flagReadAA) {
-			if (sendCmdGetResponseWithRetries(readAA, sizeof(readAA), resp, 10, 10)) {
+			if (sendCmdGetResponseWithRetries(readAA, sizeof(readAA), resp, sizeof(resp), 10, 10, start_time, &eof_time)) {
 				result_status |= FLAG_ICLASS_READER_AA;
 				memcpy(card_data + (8*5), resp, 8);
 			} else {
@@ -1746,9 +1568,14 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
 
 	uint8_t resp[ICLASS_BUFFER_SIZE];
 
-	setupIclassReader();
 	set_tracing(true);
+	clear_trace();
+	Iso15693InitReader();
 
+	StartCountSspClk();
+	uint32_t start_time = 0;
+	uint32_t eof_time = 0;
+	
 	while (!BUTTON_PRESS()) {
 
 		WDT_HIT();
@@ -1758,28 +1585,34 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
 			break;
 		}
 
-		uint8_t read_status = handshakeIclassTag(card_data);
+		uint8_t read_status = handshakeIclassTag(card_data, &eof_time);
+		start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
+
 		if (read_status < 2) continue;
 
 		//for now replay captured auth (as cc not updated)
 		memcpy(check+5, MAC, 4);
 
-		if (!sendCmdGetResponseWithRetries(check, sizeof(check), resp, 4, 5)) {
+		if (!sendCmdGetResponseWithRetries(check, sizeof(check), resp, sizeof(resp), 4, 5, start_time, &eof_time)) {
+			start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 			Dbprintf("Error: Authentication Fail!");
 			continue;
 		}
 
+		start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 		//first get configuration block (block 1)
 		crc = block_crc_LUT[1];
 		read[1] = 1;
 		read[2] = crc >> 8;
 		read[3] = crc & 0xff;
 
-		if (!sendCmdGetResponseWithRetries(read, sizeof(read),resp, 10, 10)) {
+		if (!sendCmdGetResponseWithRetries(read, sizeof(read), resp, sizeof(resp), 10, 10, start_time, &eof_time)) {
+			start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 			Dbprintf("Dump config (block 1) failed");
 			continue;
 		}
 
+		start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 		mem = resp[5];
 		memory.k16 = (mem & 0x80);
 		memory.book = (mem & 0x20);
@@ -1800,7 +1633,8 @@ void ReaderIClass_Replay(uint8_t arg0, uint8_t *MAC) {
 			read[2] = crc >> 8;
 			read[3] = crc & 0xff;
 
-			if (sendCmdGetResponseWithRetries(read, sizeof(read), resp, 10, 10)) {
+			if (sendCmdGetResponseWithRetries(read, sizeof(read), resp, sizeof(resp), 10, 10, start_time, &eof_time)) {
+				start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 				Dbprintf("     %02x: %02x %02x %02x %02x %02x %02x %02x %02x",
 						block, resp[0], resp[1], resp[2],
 						resp[3], resp[4], resp[5],
@@ -1857,7 +1691,8 @@ void iClass_Authentication(uint8_t *MAC) {
 	uint8_t resp[ICLASS_BUFFER_SIZE];
 	memcpy(check+5, MAC, 4);
 	bool isOK;
-	isOK = sendCmdGetResponseWithRetries(check, sizeof(check), resp, 4, 6);
+	uint32_t eof_time;
+	isOK = sendCmdGetResponseWithRetries(check, sizeof(check), resp, sizeof(resp), 4, 6, 0, &eof_time);
 	cmd_send(CMD_ACK,isOK, 0, 0, 0, 0);
 }
 
@@ -1867,11 +1702,12 @@ static bool iClass_ReadBlock(uint8_t blockNo, uint8_t *readdata) {
 	uint16_t rdCrc = iclass_crc16(&bl, 1);
 	readcmd[2] = rdCrc >> 8;
 	readcmd[3] = rdCrc & 0xff;
-	uint8_t resp[] = {0,0,0,0,0,0,0,0,0,0};
+	uint8_t resp[10];
 	bool isOK = false;
-
+	uint32_t eof_time;
+	
 	//readcmd[1] = blockNo;
-	isOK = sendCmdGetResponseWithRetries(readcmd, sizeof(readcmd), resp, 10, 10);
+	isOK = sendCmdGetResponseWithRetries(readcmd, sizeof(readcmd), resp, sizeof(resp), 10, 10, 0, &eof_time);
 	memcpy(readdata, resp, sizeof(resp));
 
 	return isOK;
@@ -1929,16 +1765,18 @@ static bool iClass_WriteBlock_ext(uint8_t blockNo, uint8_t *data) {
 	uint16_t wrCrc = iclass_crc16(wrCmd, 13);
 	write[14] = wrCrc >> 8;
 	write[15] = wrCrc & 0xff;
-	uint8_t resp[] = {0,0,0,0,0,0,0,0,0,0};
+	uint8_t resp[10];
 	bool isOK = false;
-
-	isOK = sendCmdGetResponseWithRetries(write, sizeof(write), resp, sizeof(resp), 10);
+	uint32_t eof_time = 0;
+	
+	isOK = sendCmdGetResponseWithRetries(write, sizeof(write), resp, sizeof(resp), 10, 10, 0, &eof_time);
+	uint32_t start_time = eof_time + DELAY_ICLASS_VICC_TO_VCD_READER;
 	if (isOK) { //if reader responded correctly
 		//Dbprintf("WriteResp: %02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",resp[0],resp[1],resp[2],resp[3],resp[4],resp[5],resp[6],resp[7],resp[8],resp[9]);
 		if (memcmp(write+2, resp, 8)) {  //if response is not equal to write values
 			if (blockNo != 3 && blockNo != 4) { //if not programming key areas (note key blocks don't get programmed with actual key data it is xor data)
 				//error try again
-				isOK = sendCmdGetResponseWithRetries(write, sizeof(write), resp, sizeof(resp), 10);
+				isOK = sendCmdGetResponseWithRetries(write, sizeof(write), resp, sizeof(resp), 10, 10, start_time, &eof_time);
 			}
 		}
 	}
diff --git a/armsrc/iso15693.c b/armsrc/iso15693.c
index 85af0859..fff8b370 100644
--- a/armsrc/iso15693.c
+++ b/armsrc/iso15693.c
@@ -64,8 +64,26 @@
 
 #define arraylen(x) (sizeof(x)/sizeof((x)[0]))
 
+// Delays in SSP_CLK ticks.
+// SSP_CLK runs at 13,56MHz / 32 = 423.75kHz when simulating a tag
+#define DELAY_READER_TO_ARM               8
+#define DELAY_ARM_TO_READER               0
+//SSP_CLK runs at 13.56MHz / 4 = 3,39MHz when acting as reader. All values should be multiples of 16
+#define DELAY_TAG_TO_ARM                 32
+#define DELAY_ARM_TO_TAG                 16
+
 static int DEBUG = 0;
 
+
+// specific LogTrace function for ISO15693: the duration needs to be scaled because otherwise it won't fit into a uint16_t
+bool LogTrace_ISO15693(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_start, uint32_t timestamp_end, uint8_t *parity, bool readerToTag) {
+	uint32_t duration = timestamp_end - timestamp_start;
+	duration /= 32;
+	timestamp_end = timestamp_start + duration;
+	return LogTrace(btBytes, iLen, timestamp_start, timestamp_end, parity, readerToTag);
+}
+
+
 ///////////////////////////////////////////////////////////////////////
 // ISO 15693 Part 2 - Air Interface
 // This section basically contains transmission and receiving of bits
@@ -84,84 +102,37 @@ static int DEBUG = 0;
 // resulting data rate is 26.48 kbit/s (fc/512)
 // cmd ... data
 // n ... length of data
-static void CodeIso15693AsReader(uint8_t *cmd, int n)
-{
-	int i, j;
+void CodeIso15693AsReader(uint8_t *cmd, int n) {
 
 	ToSendReset();
 
-	// Give it a bit of slack at the beginning
-	for(i = 0; i < 24; i++) {
-		ToSendStuffBit(1);
-	}
-
 	// SOF for 1of4
-	ToSendStuffBit(0);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(0);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	for(i = 0; i < n; i++) {
-		for(j = 0; j < 8; j += 2) {
-			int these = (cmd[i] >> j) & 3;
+	ToSend[++ToSendMax] = 0x84; //10000100
+
+	// data
+	for (int i = 0; i < n; i++) {
+		for (int j = 0; j < 8; j += 2) {
+			int these = (cmd[i] >> j) & 0x03;
 			switch(these) {
 				case 0:
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
+					ToSend[++ToSendMax] = 0x40; //01000000
 					break;
 				case 1:
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
+					ToSend[++ToSendMax] = 0x10; //00010000
 					break;
 				case 2:
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
+					ToSend[++ToSendMax] = 0x04; //00000100
 					break;
 				case 3:
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
+					ToSend[++ToSendMax] = 0x01; //00000001
 					break;
 			}
 		}
 	}
-	// EOF
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(0);
-	ToSendStuffBit(1);
-
-	// Fill remainder of last byte with 1
-	for(i = 0; i < 4; i++) {
-		ToSendStuffBit(1);
-	}
 
+	// EOF
+	ToSend[++ToSendMax] = 0x20; //0010 + 0000 padding
+	
 	ToSendMax++;
 }
 
@@ -170,46 +141,26 @@ static void CodeIso15693AsReader(uint8_t *cmd, int n)
 // is designed for more robust communication over longer distances
 static void CodeIso15693AsReader256(uint8_t *cmd, int n)
 {
-	int i, j;
-
 	ToSendReset();
 
-	// Give it a bit of slack at the beginning
-	for(i = 0; i < 24; i++) {
-		ToSendStuffBit(1);
-	}
-
 	// SOF for 1of256
-	ToSendStuffBit(0);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(0);
-
-	for(i = 0; i < n; i++) {
-		for (j = 0; j<=255; j++) {
-			if (cmd[i]==j) {
-				ToSendStuffBit(1);
+	ToSend[++ToSendMax] = 0x81; //10000001
+
+	// data
+	for(int i = 0; i < n; i++) {
+		for (int j = 0; j <= 255; j++) {
+			if (cmd[i] == j) {
 				ToSendStuffBit(0);
-			} else {
-				ToSendStuffBit(1);
 				ToSendStuffBit(1);
+			} else {
+				ToSendStuffBit(0);
+				ToSendStuffBit(0);
 			}
 		}
 	}
+
 	// EOF
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(0);
-	ToSendStuffBit(1);
-
-	// Fill remainder of last byte with 1
-	for(i = 0; i < 4; i++) {
-		ToSendStuffBit(1);
-	}
+	ToSend[++ToSendMax] = 0x20; //0010 + 0000 padding
 
 	ToSendMax++;
 }
@@ -295,27 +246,38 @@ void CodeIso15693AsTag(uint8_t *cmd, size_t len) {
 
 
 // Transmit the command (to the tag) that was placed in cmd[].
-static void TransmitTo15693Tag(const uint8_t *cmd, int len, uint32_t start_time)
-{
+void TransmitTo15693Tag(const uint8_t *cmd, int len, uint32_t *start_time) {
+
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER | FPGA_HF_READER_MODE_SEND_FULL_MOD);
-	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER);
+	
+	*start_time = (*start_time - DELAY_ARM_TO_TAG) & 0xfffffff0;
+
+	while (GetCountSspClk() > *start_time) { // we may miss the intended time
+		*start_time += 16; // next possible time
+	}
 
-	while (GetCountSspClk() < start_time) ;
+	
+	while (GetCountSspClk() < *start_time)
+		/* wait */ ;
 
 	LED_B_ON();
-	for(int c = 0; c < len; c++) {
+	for (int c = 0; c < len; c++) {
 		uint8_t data = cmd[c];
 		for (int i = 0; i < 8; i++) {
-			uint16_t send_word = (data & 0x80) ? 0x0000 : 0xffff;
+			uint16_t send_word = (data & 0x80) ? 0xffff : 0x0000;
 			while (!(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))) ;
 			AT91C_BASE_SSC->SSC_THR = send_word;
 			while (!(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY))) ;
 			AT91C_BASE_SSC->SSC_THR = send_word;
+
 			data <<= 1;
 		}
 		WDT_HIT();
 	}
 	LED_B_OFF();
+	
+	*start_time = *start_time + DELAY_ARM_TO_TAG;
+
 }
 
 
@@ -326,7 +288,7 @@ void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t *start_time,
 	// don't use the FPGA_HF_SIMULATOR_MODULATE_424K_8BIT minor mode. It would spoil GetCountSspClk()
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_MODULATE_424K);
 
-	uint32_t modulation_start_time = *start_time + 3 * 8;  // no need to transfer the unmodulated start of SOF
+	uint32_t modulation_start_time = *start_time - DELAY_ARM_TO_READER + 3 * 8;  // no need to transfer the unmodulated start of SOF
 	
 	while (GetCountSspClk() > (modulation_start_time & 0xfffffff8) + 3) { // we will miss the intended time
 		if (slot_time) {
@@ -341,7 +303,7 @@ void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t *start_time,
 
 	uint8_t shift_delay = modulation_start_time & 0x00000007;
 
-	*start_time = modulation_start_time - 3 * 8;
+	*start_time = modulation_start_time + DELAY_ARM_TO_READER - 3 * 8;
 
 	LED_C_ON();
 	uint8_t bits_to_shift = 0x00;
@@ -386,15 +348,18 @@ void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t *start_time,
 //          false if we are still waiting for some more
 //=============================================================================
 
-#define NOISE_THRESHOLD    160      // don't try to correlate noise
+#define NOISE_THRESHOLD          160                   // don't try to correlate noise
+#define MAX_PREVIOUS_AMPLITUDE   (-1 - NOISE_THRESHOLD)
 
 typedef struct DecodeTag {
 	enum {
 		STATE_TAG_SOF_LOW,
+		STATE_TAG_SOF_RISING_EDGE,
 		STATE_TAG_SOF_HIGH,
 		STATE_TAG_SOF_HIGH_END,
 		STATE_TAG_RECEIVING_DATA,
-		STATE_TAG_EOF
+		STATE_TAG_EOF,
+		STATE_TAG_EOF_TAIL
 	}         state;
 	int       bitCount;
 	int       posCount;
@@ -409,6 +374,9 @@ typedef struct DecodeTag {
 	uint8_t   *output;
 	int       len;
 	int       sum1, sum2;
+	int       threshold_sof;
+	int       threshold_half;
+	uint16_t  previous_amplitude;
 } DecodeTag_t;
 
 
@@ -416,40 +384,58 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 {
 	switch(DecodeTag->state) {
 		case STATE_TAG_SOF_LOW:
-			// waiting for 12 times low (11 times low is accepted as well)
-			if (amplitude < NOISE_THRESHOLD) {
-				DecodeTag->posCount++;
-			} else {
+			// waiting for a rising edge
+			if (amplitude > NOISE_THRESHOLD + DecodeTag->previous_amplitude) {
 				if (DecodeTag->posCount > 10) {
-					DecodeTag->posCount = 1;
-					DecodeTag->sum1 = 0;
-					DecodeTag->state = STATE_TAG_SOF_HIGH;
+					DecodeTag->threshold_sof = amplitude - DecodeTag->previous_amplitude;
+					DecodeTag->threshold_half = 0;
+					DecodeTag->state = STATE_TAG_SOF_RISING_EDGE;
 				} else {
 					DecodeTag->posCount = 0;
 				}
+			} else {
+				DecodeTag->posCount++;
+				DecodeTag->previous_amplitude = amplitude;
 			}
 			break;
 
+		case STATE_TAG_SOF_RISING_EDGE:
+			if (amplitude - DecodeTag->previous_amplitude > DecodeTag->threshold_sof) { // edge still rising
+				if (amplitude - DecodeTag->threshold_sof > DecodeTag->threshold_sof) { // steeper edge, take this as time reference
+					DecodeTag->posCount = 1;
+				} else {
+					DecodeTag->posCount = 2;
+				}
+				DecodeTag->threshold_sof = (amplitude - DecodeTag->previous_amplitude) / 2;
+			} else {
+				DecodeTag->posCount = 2;
+				DecodeTag->threshold_sof = DecodeTag->threshold_sof/2;
+			}
+			// DecodeTag->posCount = 2;
+			DecodeTag->state = STATE_TAG_SOF_HIGH;
+			break;
+				
 		case STATE_TAG_SOF_HIGH:
 			// waiting for 10 times high. Take average over the last 8
-			if (amplitude > NOISE_THRESHOLD) {
+			if (amplitude > DecodeTag->threshold_sof) {
 				DecodeTag->posCount++;
 				if (DecodeTag->posCount > 2) {
-					DecodeTag->sum1 += amplitude; // keep track of average high value
+					DecodeTag->threshold_half += amplitude; // keep track of average high value
 				}
 				if (DecodeTag->posCount == 10) {
-					DecodeTag->sum1 >>= 4;        // calculate half of average high value (8 samples)
+					DecodeTag->threshold_half >>= 2; // (4 times 1/2 average)
 					DecodeTag->state = STATE_TAG_SOF_HIGH_END;
 				}
 			} else { // high phase was too short
 				DecodeTag->posCount = 1;
+				DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 				DecodeTag->state = STATE_TAG_SOF_LOW;
 			}
 			break;
 
 		case STATE_TAG_SOF_HIGH_END:
-			// waiting for a falling edge
-			if (amplitude < DecodeTag->sum1) {   // signal drops below 50% average high: a falling edge
+			// check for falling edge
+			if (DecodeTag->posCount == 13 && amplitude < DecodeTag->threshold_sof) {
 				DecodeTag->lastBit = SOF_PART1;  // detected 1st part of SOF (12 samples low and 12 samples high)
 				DecodeTag->shiftReg = 0;
 				DecodeTag->bitCount = 0;
@@ -458,11 +444,18 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 				DecodeTag->sum2 = 0;
 				DecodeTag->posCount = 2;
 				DecodeTag->state = STATE_TAG_RECEIVING_DATA;
+				// FpgaDisableTracing(); // DEBUGGING
+				// Dbprintf("amplitude = %d, threshold_sof = %d, threshold_half/4 = %d, previous_amplitude = %d", 
+					// amplitude, 
+					// DecodeTag->threshold_sof, 
+					// DecodeTag->threshold_half/4,
+					// DecodeTag->previous_amplitude); // DEBUGGING
 				LED_C_ON();
 			} else {
 				DecodeTag->posCount++;
 				if (DecodeTag->posCount > 13) { // high phase too long
 					DecodeTag->posCount = 0;
+					DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 					DecodeTag->state = STATE_TAG_SOF_LOW;
 					LED_C_OFF();
 				}
@@ -480,18 +473,16 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 				DecodeTag->sum2 += amplitude;
 			}
 			if (DecodeTag->posCount == 8) {
-				int32_t corr_1 = DecodeTag->sum2 - DecodeTag->sum1;
-				int32_t corr_0 = -corr_1;
-				int32_t corr_EOF = (DecodeTag->sum1 + DecodeTag->sum2) / 2;
-				if (corr_EOF > corr_0 && corr_EOF > corr_1) {
+				if (DecodeTag->sum1 > DecodeTag->threshold_half && DecodeTag->sum2 > DecodeTag->threshold_half) { // modulation in both halves
 					if (DecodeTag->lastBit == LOGIC0) {  // this was already part of EOF
 						DecodeTag->state = STATE_TAG_EOF;
 					} else {
 						DecodeTag->posCount = 0;
+						DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 						DecodeTag->state = STATE_TAG_SOF_LOW;
 						LED_C_OFF();
 					}
-				} else if (corr_1 > corr_0) {
+				} else if (DecodeTag->sum1 < DecodeTag->threshold_half && DecodeTag->sum2 > DecodeTag->threshold_half) { // modulation in second half
 					// logic 1
 					if (DecodeTag->lastBit == SOF_PART1) { // still part of SOF
 						DecodeTag->lastBit = SOF_PART2;    // SOF completed
@@ -503,20 +494,21 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 						if (DecodeTag->bitCount == 8) {
 							DecodeTag->output[DecodeTag->len] = DecodeTag->shiftReg;
 							DecodeTag->len++;
+							// if (DecodeTag->shiftReg == 0x12 && DecodeTag->len == 1) FpgaDisableTracing(); // DEBUGGING
 							if (DecodeTag->len > DecodeTag->max_len) {
 								// buffer overflow, give up
-								DecodeTag->posCount = 0;
-								DecodeTag->state = STATE_TAG_SOF_LOW;
 								LED_C_OFF();
+								return true;
 							}
 							DecodeTag->bitCount = 0;
 							DecodeTag->shiftReg = 0;
 						}
 					}
-				} else {
+				} else if (DecodeTag->sum1 > DecodeTag->threshold_half && DecodeTag->sum2 < DecodeTag->threshold_half) { // modulation in first half
 					// logic 0
 					if (DecodeTag->lastBit == SOF_PART1) { // incomplete SOF
 						DecodeTag->posCount = 0;
+						DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 						DecodeTag->state = STATE_TAG_SOF_LOW;
 						LED_C_OFF();
 					} else {
@@ -526,9 +518,11 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 						if (DecodeTag->bitCount == 8) {
 							DecodeTag->output[DecodeTag->len] = DecodeTag->shiftReg;
 							DecodeTag->len++;
+							// if (DecodeTag->shiftReg == 0x12 && DecodeTag->len == 1) FpgaDisableTracing(); // DEBUGGING
 							if (DecodeTag->len > DecodeTag->max_len) {
 								// buffer overflow, give up
 								DecodeTag->posCount = 0;
+								DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 								DecodeTag->state = STATE_TAG_SOF_LOW;
 								LED_C_OFF();
 							}
@@ -536,6 +530,15 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 							DecodeTag->shiftReg = 0;
 						}
 					}
+				} else { // no modulation
+					if (DecodeTag->lastBit == SOF_PART2) { // only SOF (this is OK for iClass)
+						LED_C_OFF();
+						return true;
+					} else {
+						DecodeTag->posCount = 0;
+						DecodeTag->state = STATE_TAG_SOF_LOW;
+						LED_C_OFF();
+					}
 				}
 				DecodeTag->posCount = 0;
 			}
@@ -553,21 +556,42 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 				DecodeTag->sum2 += amplitude;
 			}
 			if (DecodeTag->posCount == 8) {
-				int32_t corr_1 = DecodeTag->sum2 - DecodeTag->sum1;
-				int32_t corr_0 = -corr_1;
-				int32_t corr_EOF = (DecodeTag->sum1 + DecodeTag->sum2) / 2;
-				if (corr_EOF > corr_0 || corr_1 > corr_0) {
+				if (DecodeTag->sum1 > DecodeTag->threshold_half && DecodeTag->sum2 < DecodeTag->threshold_half) { // modulation in first half
 					DecodeTag->posCount = 0;
+					DecodeTag->state = STATE_TAG_EOF_TAIL;
+				} else {
+					DecodeTag->posCount = 0;
+					DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 					DecodeTag->state = STATE_TAG_SOF_LOW;
 					LED_C_OFF();
-				} else {
+				}
+			}
+			DecodeTag->posCount++;
+			break;
+
+		case STATE_TAG_EOF_TAIL:
+			if (DecodeTag->posCount == 1) {
+				DecodeTag->sum1 = 0;
+				DecodeTag->sum2 = 0;
+			}
+			if (DecodeTag->posCount <= 4) {
+				DecodeTag->sum1 += amplitude;
+			} else {
+				DecodeTag->sum2 += amplitude;
+			}
+			if (DecodeTag->posCount == 8) {
+				if (DecodeTag->sum1 < DecodeTag->threshold_half && DecodeTag->sum2 < DecodeTag->threshold_half) { // no modulation in both halves
 					LED_C_OFF();
 					return true;
+				} else {
+					DecodeTag->posCount = 0;
+					DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
+					DecodeTag->state = STATE_TAG_SOF_LOW;
+					LED_C_OFF();
 				}
 			}
 			DecodeTag->posCount++;
 			break;
-
 	}
 
 	return false;
@@ -576,6 +600,7 @@ static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint1
 
 static void DecodeTagInit(DecodeTag_t *DecodeTag, uint8_t *data, uint16_t max_len)
 {
+	DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 	DecodeTag->posCount = 0;
 	DecodeTag->state = STATE_TAG_SOF_LOW;
 	DecodeTag->output = data;
@@ -587,18 +612,19 @@ static void DecodeTagReset(DecodeTag_t *DecodeTag)
 {
 	DecodeTag->posCount = 0;
 	DecodeTag->state = STATE_TAG_SOF_LOW;
+	DecodeTag->previous_amplitude = MAX_PREVIOUS_AMPLITUDE;
 }
 
 
 /*
  *  Receive and decode the tag response, also log to tracebuffer
  */
-static int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, int timeout)
-{
+int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, uint16_t timeout, uint32_t *eof_time) {
+
 	int samples = 0;
-	bool gotFrame = false;
+	int ret = 0;
 
-	uint16_t *dmaBuf = (uint16_t*)BigBuf_malloc(ISO15693_DMA_BUFFER_SIZE*sizeof(uint16_t));
+	uint16_t dmaBuf[ISO15693_DMA_BUFFER_SIZE];
 
 	// the Decoder data structure
 	DecodeTag_t DecodeTag = { 0 };
@@ -613,6 +639,7 @@ static int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, int tim
 	// Setup and start DMA.
 	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER);
 	FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+	uint32_t dma_start_time = 0;
 	uint16_t *upTo = dmaBuf;
 
 	for(;;) {
@@ -620,12 +647,19 @@ static int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, int tim
 
 		if (behindBy == 0) continue;
 
+		samples++;
+		if (samples == 1) {
+		    // DMA has transferred the very first data
+			dma_start_time = GetCountSspClk() & 0xfffffff0;
+		}
+		
 		uint16_t tagdata = *upTo++;
 
 		if(upTo >= dmaBuf + ISO15693_DMA_BUFFER_SIZE) {                // we have read all of the DMA buffer content.
 			upTo = dmaBuf;                                             // start reading the circular buffer from the beginning
 			if(behindBy > (9*ISO15693_DMA_BUFFER_SIZE/10)) {
 				Dbprintf("About to blow circular buffer - aborted! behindBy=%d", behindBy);
+				ret = -1;
 				break;
 			}
 		}
@@ -634,30 +668,42 @@ static int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, int tim
 			AT91C_BASE_PDC_SSC->PDC_RNCR = ISO15693_DMA_BUFFER_SIZE;   // DMA Next Counter registers
 		}
 
-		samples++;
-
 		if (Handle15693SamplesFromTag(tagdata, &DecodeTag)) {
-			gotFrame = true;
+			*eof_time = dma_start_time + samples*16 - DELAY_TAG_TO_ARM; // end of EOF
+			if (DecodeTag.lastBit == SOF_PART2) {
+				*eof_time -= 8*16; // needed 8 additional samples to confirm single SOF (iCLASS)
+			}
+			if (DecodeTag.len > DecodeTag.max_len) {
+				ret = -2; // buffer overflow
+			}
 			break;
 		}
 
 		if (samples > timeout && DecodeTag.state < STATE_TAG_RECEIVING_DATA) {
-			DecodeTag.len = 0;
+			ret = -1;	// timeout
 			break;
 		}
 
 	}
 
 	FpgaDisableSscDma();
-	BigBuf_free();
 
-	if (DEBUG) Dbprintf("samples = %d, gotFrame = %d, Decoder: state = %d, len = %d, bitCount = %d, posCount = %d",
-						samples, gotFrame, DecodeTag.state, DecodeTag.len, DecodeTag.bitCount, DecodeTag.posCount);
+	if (DEBUG) Dbprintf("samples = %d, ret = %d, Decoder: state = %d, lastBit = %d, len = %d, bitCount = %d, posCount = %d",
+						samples, ret, DecodeTag.state, DecodeTag.lastBit, DecodeTag.len, DecodeTag.bitCount, DecodeTag.posCount);
 
-	if (DecodeTag.len > 0) {
-		LogTrace(DecodeTag.output, DecodeTag.len, 0, 0, NULL, false);
+	if (ret < 0) {
+		return ret;
 	}
 
+	uint32_t sof_time = *eof_time
+						- DecodeTag.len * 8 * 8 * 16 // time for byte transfers
+						- 32 * 16  // time for SOF transfer
+						- (DecodeTag.lastBit != SOF_PART2?32*16:0); // time for EOF transfer
+						
+	if (DEBUG) Dbprintf("timing: sof_time = %d, eof_time = %d", sof_time, *eof_time);
+	
+	LogTrace_ISO15693(DecodeTag.output, DecodeTag.len, sof_time*4, *eof_time*4, NULL, false);
+
 	return DecodeTag.len;
 }
 
@@ -977,7 +1023,7 @@ int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint32_t *eo
 
 		for (int i = 7; i >= 0; i--) {
 			if (Handle15693SampleFromReader((b >> i) & 0x01, &DecodeReader)) {
-				*eof_time = dma_start_time + samples - DELAY_READER_TO_ARM_SIM; // end of EOF
+				*eof_time = dma_start_time + samples - DELAY_READER_TO_ARM; // end of EOF
 				gotFrame = true;
 				break;
 			}
@@ -1006,7 +1052,7 @@ int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint32_t *eo
 						- DecodeReader.byteCount * (DecodeReader.Coding==CODING_1_OUT_OF_4?128:2048) // time for byte transfers
 						- 32  // time for SOF transfer
 						- 16; // time for EOF transfer
-		LogTrace(DecodeReader.output, DecodeReader.byteCount, sof_time, *eof_time, NULL, true);
+		LogTrace_ISO15693(DecodeReader.output, DecodeReader.byteCount, sof_time*32, *eof_time*32, NULL, true);
 	}
 
 	return DecodeReader.byteCount;
@@ -1060,7 +1106,8 @@ void AcquireRawAdcSamplesIso15693(void)
 	SpinDelay(100);
 
 	// Now send the command
-	TransmitTo15693Tag(ToSend, ToSendMax, 0);
+	uint32_t start_time = 0;
+	TransmitTo15693Tag(ToSend, ToSendMax, &start_time);
 
 	// wait for last transfer to complete
 	while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY)) ;
@@ -1156,7 +1203,7 @@ void SnoopIso15693(void)
 			if (Handle15693SampleFromReader(snoopdata & 0x02, &DecodeReader)) {
 				FpgaDisableSscDma();
 				ExpectTagAnswer = true;
-				LogTrace(DecodeReader.output, DecodeReader.byteCount, samples, samples, NULL, true);
+				LogTrace_ISO15693(DecodeReader.output, DecodeReader.byteCount, samples*64, samples*64, NULL, true);
 				/* And ready to receive another command. */
 				DecodeReaderReset(&DecodeReader);
 				/* And also reset the demod code, which might have been */
@@ -1168,7 +1215,7 @@ void SnoopIso15693(void)
 			if (Handle15693SampleFromReader(snoopdata & 0x01, &DecodeReader)) {
 				FpgaDisableSscDma();
 				ExpectTagAnswer = true;
-				LogTrace(DecodeReader.output, DecodeReader.byteCount, samples, samples, NULL, true);
+				LogTrace_ISO15693(DecodeReader.output, DecodeReader.byteCount, samples*64, samples*64, NULL, true);
 				/* And ready to receive another command. */
 				DecodeReaderReset(&DecodeReader);
 				/* And also reset the demod code, which might have been */
@@ -1184,7 +1231,7 @@ void SnoopIso15693(void)
 			if (Handle15693SamplesFromTag(snoopdata >> 2, &DecodeTag)) {
 				FpgaDisableSscDma();
 				//Use samples as a time measurement
-				LogTrace(DecodeTag.output, DecodeTag.len, samples, samples, NULL, false);
+				LogTrace_ISO15693(DecodeTag.output, DecodeTag.len, samples*64, samples*64, NULL, false);
 				// And ready to receive another response.
 				DecodeTagReset(&DecodeTag);
 				DecodeReaderReset(&DecodeReader);
@@ -1213,10 +1260,8 @@ void SnoopIso15693(void)
 
 
 // Initialize the proxmark as iso15k reader
-static void Iso15693InitReader() {
+void Iso15693InitReader() {
 	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
-	// Setup SSC
-	// FpgaSetupSsc();
 
 	// Start from off (no field generated)
 	LED_D_OFF();
@@ -1300,17 +1345,20 @@ static void BuildInventoryResponse(uint8_t *uid)
 //  init ... should we initialize the reader?
 //  speed ... 0 low speed, 1 hi speed
 //  *recv will contain the tag's answer
-//  return: lenght of received data
-int SendDataTag(uint8_t *send, int sendlen, bool init, int speed, uint8_t *recv, uint16_t max_recv_len, uint32_t start_time) {
+//  return: length of received data, or -1 for timeout
+int SendDataTag(uint8_t *send, int sendlen, bool init, int speed, uint8_t *recv, uint16_t max_recv_len, uint32_t start_time, uint32_t *eof_time) {
 
 	LED_A_ON();
 	LED_B_OFF();
 	LED_C_OFF();
 
-	if (init) Iso15693InitReader();
-
-	int answerLen=0;
-
+	if (init) {
+		Iso15693InitReader();
+		StartCountSspClk();
+	}
+	
+	int answerLen = 0;
+	
 	if (!speed) {
 		// low speed (1 out of 256)
 		CodeIso15693AsReader256(send, sendlen);
@@ -1319,11 +1367,14 @@ int SendDataTag(uint8_t *send, int sendlen, bool init, int speed, uint8_t *recv,
 		CodeIso15693AsReader(send, sendlen);
 	}
 
-	TransmitTo15693Tag(ToSend, ToSendMax, start_time);
+	if (start_time == 0) {
+		start_time = GetCountSspClk();
+	}
+	TransmitTo15693Tag(ToSend, ToSendMax, &start_time);
 
 	// Now wait for a response
 	if (recv != NULL) {
-		answerLen = GetIso15693AnswerFromTag(recv, max_recv_len, DELAY_ISO15693_VCD_TO_VICC_READER * 2);
+		answerLen = GetIso15693AnswerFromTag(recv, max_recv_len, DELAY_ISO15693_VCD_TO_VICC_READER * 2, eof_time);
 	}
 
 	LED_A_OFF();
@@ -1445,11 +1496,13 @@ void ReaderIso15693(uint32_t parameter)
 
 	// Now send the IDENTIFY command
 	BuildIdentifyRequest();
-	TransmitTo15693Tag(ToSend, ToSendMax, 0);
+	uint32_t start_time = 0;
+	TransmitTo15693Tag(ToSend, ToSendMax, &start_time);
 
 	// Now wait for a response
-	answerLen = GetIso15693AnswerFromTag(answer, sizeof(answer), DELAY_ISO15693_VCD_TO_VICC_READER * 2) ;
-	uint32_t start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD_READER;
+	uint32_t eof_time;
+	answerLen = GetIso15693AnswerFromTag(answer, sizeof(answer), DELAY_ISO15693_VCD_TO_VICC_READER * 2, &eof_time) ;
+	start_time = eof_time + DELAY_ISO15693_VICC_TO_VCD_READER;
 
 	if (answerLen >=12) // we should do a better check than this
 	{
@@ -1487,9 +1540,9 @@ void ReaderIso15693(uint32_t parameter)
 	if (answerLen >= 12 && DEBUG) {
 		for (int i = 0; i < 32; i++) {  // sanity check, assume max 32 pages
 			BuildReadBlockRequest(TagUID, i);
-			TransmitTo15693Tag(ToSend, ToSendMax, start_time);
-			int answerLen = GetIso15693AnswerFromTag(answer, sizeof(answer), DELAY_ISO15693_VCD_TO_VICC_READER * 2);
-			start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD_READER;
+			TransmitTo15693Tag(ToSend, ToSendMax, &start_time);
+			int answerLen = GetIso15693AnswerFromTag(answer, sizeof(answer), DELAY_ISO15693_VCD_TO_VICC_READER * 2, &eof_time);
+			start_time = eof_time + DELAY_ISO15693_VICC_TO_VCD_READER;
 			if (answerLen > 0) {
 				Dbprintf("READ SINGLE BLOCK %d returned %d octets:", i, answerLen);
 				DbdecodeIso15693Answer(answerLen, answer);
@@ -1535,7 +1588,7 @@ void SimTagIso15693(uint32_t parameter, uint8_t *uid)
 
 		if ((cmd_len >= 5) && (cmd[0] & ISO15693_REQ_INVENTORY) && (cmd[1] == ISO15693_INVENTORY)) { // TODO: check more flags
 			bool slow = !(cmd[0] & ISO15693_REQ_DATARATE_HIGH);
-			start_time = eof_time + DELAY_ISO15693_VCD_TO_VICC_SIM - DELAY_ARM_TO_READER_SIM;
+			start_time = eof_time + DELAY_ISO15693_VCD_TO_VICC_SIM;
 			TransmitTo15693Reader(ToSend, ToSendMax, &start_time, 0, slow);
 		}
 
@@ -1557,11 +1610,8 @@ void BruteforceIso15693Afi(uint32_t speed)
 
 	uint8_t data[6];
 	uint8_t recv[ISO15693_MAX_RESPONSE_LENGTH];
-
-	int datalen=0, recvlen=0;
-
-	Iso15693InitReader();
-	StartCountSspClk();
+	int datalen = 0, recvlen = 0;
+	uint32_t eof_time;
 
 	// first without AFI
 	// Tags should respond without AFI and with AFI=0 even when AFI is active
@@ -1570,8 +1620,9 @@ void BruteforceIso15693Afi(uint32_t speed)
 	data[1] = ISO15693_INVENTORY;
 	data[2] = 0; // mask length
 	datalen = Iso15693AddCrc(data,3);
-	recvlen = SendDataTag(data, datalen, false, speed, recv, sizeof(recv), 0);
-	uint32_t start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD_READER;
+	uint32_t start_time = GetCountSspClk();
+	recvlen = SendDataTag(data, datalen, true, speed, recv, sizeof(recv), 0, &eof_time);
+	start_time = eof_time + DELAY_ISO15693_VICC_TO_VCD_READER;
 	WDT_HIT();
 	if (recvlen>=12) {
 		Dbprintf("NoAFI UID=%s", Iso15693sprintUID(NULL, &recv[2]));
@@ -1587,8 +1638,8 @@ void BruteforceIso15693Afi(uint32_t speed)
 	for (int i = 0; i < 256; i++) {
 		data[2] = i & 0xFF;
 		datalen = Iso15693AddCrc(data,4);
-		recvlen = SendDataTag(data, datalen, false, speed, recv, sizeof(recv), start_time);
-		start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD_READER;
+		recvlen = SendDataTag(data, datalen, false, speed, recv, sizeof(recv), start_time, &eof_time);
+		start_time = eof_time + DELAY_ISO15693_VICC_TO_VCD_READER;
 		WDT_HIT();
 		if (recvlen >= 12) {
 			Dbprintf("AFI=%i UID=%s", i, Iso15693sprintUID(NULL, &recv[2]));
@@ -1605,7 +1656,8 @@ void DirectTag15693Command(uint32_t datalen, uint32_t speed, uint32_t recv, uint
 
 	int recvlen = 0;
 	uint8_t recvbuf[ISO15693_MAX_RESPONSE_LENGTH];
-
+	uint32_t eof_time;
+	
 	LED_A_ON();
 
 	if (DEBUG) {
@@ -1613,24 +1665,27 @@ void DirectTag15693Command(uint32_t datalen, uint32_t speed, uint32_t recv, uint
 		Dbhexdump(datalen, data, false);
 	}
 
-	recvlen = SendDataTag(data, datalen, true, speed, (recv?recvbuf:NULL), sizeof(recvbuf), 0);
+	recvlen = SendDataTag(data, datalen, true, speed, (recv?recvbuf:NULL), sizeof(recvbuf), 0, &eof_time);
+
+	// for the time being, switch field off to protect rdv4.0
+	// note: this prevents using hf 15 cmd with s option - which isn't implemented yet anyway
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	LED_D_OFF();
 
 	if (recv) {
 		if (DEBUG) {
 			Dbprintf("RECV:");
-			Dbhexdump(recvlen, recvbuf, false);
-			DbdecodeIso15693Answer(recvlen, recvbuf);
+			if (recvlen > 0) {
+				Dbhexdump(recvlen, recvbuf, false);
+				DbdecodeIso15693Answer(recvlen, recvbuf);
+			}
 		}
-
-		cmd_send(CMD_ACK, recvlen>ISO15693_MAX_RESPONSE_LENGTH?ISO15693_MAX_RESPONSE_LENGTH:recvlen, 0, 0, recvbuf, ISO15693_MAX_RESPONSE_LENGTH);
-
+		if (recvlen > ISO15693_MAX_RESPONSE_LENGTH) {
+			recvlen = ISO15693_MAX_RESPONSE_LENGTH;
+		}
+		cmd_send(CMD_ACK, recvlen, 0, 0, recvbuf, ISO15693_MAX_RESPONSE_LENGTH);
 	}
 
-	// for the time being, switch field off to protect rdv4.0
-	// note: this prevents using hf 15 cmd with s option - which isn't implemented yet anyway
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	LED_D_OFF();
-
 	LED_A_OFF();
 }
 
@@ -1648,7 +1703,8 @@ void SetTag15693Uid(uint8_t *uid)
 
 	int recvlen = 0;
 	uint8_t recvbuf[ISO15693_MAX_RESPONSE_LENGTH];
-
+	uint32_t eof_time;
+	
 	LED_A_ON();
 
 	// Command 1 : 02213E00000000
@@ -1687,7 +1743,7 @@ void SetTag15693Uid(uint8_t *uid)
 	cmd[3][5] = uid[1];
 	cmd[3][6] = uid[0];
 
-	for (int i=0; i<4; i++) {
+	for (int i = 0; i < 4; i++) {
 		// Add the CRC
 		crc = Iso15693Crc(cmd[i], 7);
 		cmd[i][7] = crc & 0xff;
@@ -1698,12 +1754,14 @@ void SetTag15693Uid(uint8_t *uid)
 			Dbhexdump(sizeof(cmd[i]), cmd[i], false);
 		}
 
-		recvlen = SendDataTag(cmd[i], sizeof(cmd[i]), true, 1, recvbuf, sizeof(recvbuf), 0);
+		recvlen = SendDataTag(cmd[i], sizeof(cmd[i]), true, 1, recvbuf, sizeof(recvbuf), 0, &eof_time);
 
 		if (DEBUG) {
 			Dbprintf("RECV:");
-			Dbhexdump(recvlen, recvbuf, false);
-			DbdecodeIso15693Answer(recvlen, recvbuf);
+			if (recvlen > 0) {
+				Dbhexdump(recvlen, recvbuf, false);
+				DbdecodeIso15693Answer(recvlen, recvbuf);
+			}
 		}
 
 		cmd_send(CMD_ACK, recvlen>ISO15693_MAX_RESPONSE_LENGTH?ISO15693_MAX_RESPONSE_LENGTH:recvlen, 0, 0, recvbuf, ISO15693_MAX_RESPONSE_LENGTH);
diff --git a/armsrc/iso15693.h b/armsrc/iso15693.h
index 7d2e7598..96a2b39b 100644
--- a/armsrc/iso15693.h
+++ b/armsrc/iso15693.h
@@ -17,16 +17,18 @@
 
 // Delays in SSP_CLK ticks.
 // SSP_CLK runs at 13,56MHz / 32 = 423.75kHz when simulating a tag
-#define DELAY_READER_TO_ARM_SIM           8
-#define DELAY_ARM_TO_READER_SIM           0
-#define DELAY_ISO15693_VCD_TO_VICC_SIM    132  // 132/423.75kHz = 311.5us from end of command EOF to start of tag response
-//SSP_CLK runs at 13.56MHz / 4 = 3,39MHz when acting as reader
+#define DELAY_ISO15693_VCD_TO_VICC_SIM     132  // 132/423.75kHz = 311.5us from end of command EOF to start of tag response
+//SSP_CLK runs at 13.56MHz / 4 = 3,39MHz when acting as reader. All values should be multiples of 16
 #define DELAY_ISO15693_VCD_TO_VICC_READER 1056 // 1056/3,39MHz = 311.5us from end of command EOF to start of tag response
-#define DELAY_ISO15693_VICC_TO_VCD_READER 1017 // 1017/3.39MHz = 300us between end of tag response and next reader command
+#define DELAY_ISO15693_VICC_TO_VCD_READER 1024 // 1024/3.39MHz = 302.1us between end of tag response and next reader command
 
+void Iso15693InitReader();
+void CodeIso15693AsReader(uint8_t *cmd, int n);
 void CodeIso15693AsTag(uint8_t *cmd, size_t len);
-int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint32_t *eof_time);
 void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t *start_time, uint32_t slot_time, bool slow);
+int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint32_t *eof_time);
+void TransmitTo15693Tag(const uint8_t *cmd, int len, uint32_t *start_time);
+int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, uint16_t timeout, uint32_t *eof_time);
 void SnoopIso15693(void);
 void AcquireRawAdcSamplesIso15693(void);
 void ReaderIso15693(uint32_t parameter);
@@ -35,5 +37,6 @@ void BruteforceIso15693Afi(uint32_t speed);
 void DirectTag15693Command(uint32_t datalen, uint32_t speed, uint32_t recv, uint8_t data[]);
 void SetTag15693Uid(uint8_t *uid);
 void SetDebugIso15693(uint32_t flag);
+bool LogTrace_ISO15693(const uint8_t *btBytes, uint16_t iLen, uint32_t timestamp_start, uint32_t timestamp_end, uint8_t *parity, bool readerToTag);
 
 #endif
diff --git a/armsrc/util.c b/armsrc/util.c
index aac68a34..4bff3a26 100644
--- a/armsrc/util.c
+++ b/armsrc/util.c
@@ -21,7 +21,7 @@ void print_result(char *name, uint8_t *buf, size_t len) {
 
    if ( len % 16 == 0 ) {
 	   for(; p-buf < len; p += 16)
-       Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
+	   Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x %02x",
 				name,
 				p-buf,
 				len,
@@ -30,7 +30,7 @@ void print_result(char *name, uint8_t *buf, size_t len) {
    }
    else {
    for(; p-buf < len; p += 8)
-       Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x", name, p-buf, len, p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
+	   Dbprintf("[%s:%d/%d] %02x %02x %02x %02x %02x %02x %02x %02x", name, p-buf, len, p[0], p[1], p[2], p[3], p[4], p[5], p[6], p[7]);
    }
 }
 
@@ -68,17 +68,17 @@ uint64_t bytes_to_num(uint8_t* src, size_t len)
 
 // RotateLeft - Ultralight, Desfire
 void rol(uint8_t *data, const size_t len){
-    uint8_t first = data[0];
-    for (size_t i = 0; i < len-1; i++) {
-        data[i] = data[i+1];
-    }
-    data[len-1] = first;
+	uint8_t first = data[0];
+	for (size_t i = 0; i < len-1; i++) {
+		data[i] = data[i+1];
+	}
+	data[len-1] = first;
 }
 void lsl (uint8_t *data, size_t len) {
-    for (size_t n = 0; n < len - 1; n++) {
-        data[n] = (data[n] << 1) | (data[n+1] >> 7);
-    }
-    data[len - 1] <<= 1;
+	for (size_t n = 0; n < len - 1; n++) {
+		data[n] = (data[n] << 1) | (data[n+1] >> 7);
+	}
+	data[len - 1] <<= 1;
 }
 
 void LEDsoff()
@@ -309,16 +309,16 @@ void FormatVersionInformation(char *dst, int len, const char *prefix, void *vers
 //  -------------------------------------------------------------------------
 //  test procedure:
 //
-//	ti = GetTickCount();
-//	SpinDelay(1000);
-//	ti = GetTickCount() - ti;
-//	Dbprintf("timer(1s): %d t=%d", ti, GetTickCount());
+//  ti = GetTickCount();
+//  SpinDelay(1000);
+//  ti = GetTickCount() - ti;
+//  Dbprintf("timer(1s): %d t=%d", ti, GetTickCount());
 
 void StartTickCount()
 {
 	// This timer is based on the slow clock. The slow clock frequency is between 22kHz and 40kHz.
 	// We can determine the actual slow clock frequency by looking at the Main Clock Frequency Register.
-    uint16_t mainf = AT91C_BASE_PMC->PMC_MCFR & 0xffff;		// = 16 * main clock frequency (16MHz) / slow clock frequency
+	uint16_t mainf = AT91C_BASE_PMC->PMC_MCFR & 0xffff;     // = 16 * main clock frequency (16MHz) / slow clock frequency
 	// set RealTimeCounter divider to count at 1kHz:
 	AT91C_BASE_RTTC->RTTC_RTMR = AT91C_RTTC_RTTRST | ((256000 + (mainf/2)) / mainf);
 	// note: worst case precision is approx 2.5%
@@ -334,12 +334,12 @@ uint32_t RAMFUNC GetTickCount(){
 
 
 //  -------------------------------------------------------------------------
-//  microseconds timer 
+//  microseconds timer
 //  -------------------------------------------------------------------------
 void StartCountUS()
 {
 	AT91C_BASE_PMC->PMC_PCER |= (0x1 << 12) | (0x1 << 13) | (0x1 << 14);
-//	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC1XC1S_TIOA0;
+//  AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC1XC1S_TIOA0;
 	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
 
 	// fast clock
@@ -349,10 +349,10 @@ void StartCountUS()
 														AT91C_TC_ACPC_SET | AT91C_TC_ASWTRG_SET;
 	AT91C_BASE_TC0->TC_RA = 1;
 	AT91C_BASE_TC0->TC_RC = 0xBFFF + 1; // 0xC000
-	
-	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // timer disable  
+
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; // timer disable
 	AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_XC1; // from timer 0
-	
+
 	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
 	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN;
 	AT91C_BASE_TCB->TCB_BCR = 1;
@@ -375,61 +375,72 @@ uint32_t RAMFUNC GetDeltaCountUS(){
 
 
 //  -------------------------------------------------------------------------
-//  Timer for iso14443 commands. Uses ssp_clk from FPGA 
+//  Timer for iso14443 commands. Uses ssp_clk from FPGA
 //  -------------------------------------------------------------------------
 void StartCountSspClk()
 {
 	AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC0) | (1 << AT91C_ID_TC1) | (1 << AT91C_ID_TC2);  // Enable Clock to all timers
-	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_TIOA1 		// XC0 Clock = TIOA1
-							| AT91C_TCB_TC1XC1S_NONE 		// XC1 Clock = none
-							| AT91C_TCB_TC2XC2S_TIOA0;		// XC2 Clock = TIOA0
+	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_TIOA1       // XC0 Clock = TIOA1
+							| AT91C_TCB_TC1XC1S_NONE        // XC1 Clock = none
+							| AT91C_TCB_TC2XC2S_TIOA0;      // XC2 Clock = TIOA0
 
 	// configure TC1 to create a short pulse on TIOA1 when a rising edge on TIOB1 (= ssp_clk from FPGA) occurs:
-	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS; 				// disable TC1
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;               // disable TC1
 	AT91C_BASE_TC1->TC_CMR = AT91C_TC_CLKS_TIMER_DIV1_CLOCK // TC1 Clock = MCK(48MHz)/2 = 24MHz
-							| AT91C_TC_CPCSTOP				// Stop clock on RC compare
-							| AT91C_TC_EEVTEDG_RISING		// Trigger on rising edge of Event
-							| AT91C_TC_EEVT_TIOB			// Event-Source: TIOB1 (= ssp_clk from FPGA = 13,56MHz/16 ... 13,56MHz/4)
-							| AT91C_TC_ENETRG				// Enable external trigger event
-							| AT91C_TC_WAVESEL_UP	 		// Upmode without automatic trigger on RC compare
-							| AT91C_TC_WAVE 				// Waveform Mode
-							| AT91C_TC_AEEVT_SET 			// Set TIOA1 on external event
-							| AT91C_TC_ACPC_CLEAR; 			// Clear TIOA1 on RC Compare
-	AT91C_BASE_TC1->TC_RC = 0x02; 							// RC Compare value = 0x02
+							| AT91C_TC_CPCSTOP              // Stop clock on RC compare
+							| AT91C_TC_EEVTEDG_RISING       // Trigger on rising edge of Event
+							| AT91C_TC_EEVT_TIOB            // Event-Source: TIOB1 (= ssp_clk from FPGA = 13,56MHz/16 ... 13,56MHz/4)
+							| AT91C_TC_ENETRG               // Enable external trigger event
+							| AT91C_TC_WAVESEL_UP           // Upmode without automatic trigger on RC compare
+							| AT91C_TC_WAVE                 // Waveform Mode
+							| AT91C_TC_AEEVT_SET            // Set TIOA1 on external event
+							| AT91C_TC_ACPC_CLEAR;          // Clear TIOA1 on RC Compare
+	AT91C_BASE_TC1->TC_RC = 0x02;                           // RC Compare value = 0x02
 
 	// use TC0 to count TIOA1 pulses
-	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;				// disable TC0
-	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_XC0	 			// TC0 clock = XC0 clock = TIOA1
-							| AT91C_TC_WAVE 				// Waveform Mode
-							| AT91C_TC_WAVESEL_UP	 		// just count
-							| AT91C_TC_ACPA_CLEAR 			// Clear TIOA0 on RA Compare
-							| AT91C_TC_ACPC_SET; 			// Set TIOA0 on RC Compare
-	AT91C_BASE_TC0->TC_RA = 1;								// RA Compare value = 1; pulse width to TC2
-	AT91C_BASE_TC0->TC_RC = 0; 								// RC Compare value = 0; increment TC2 on overflow
+	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;               // disable TC0
+	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_XC0              // TC0 clock = XC0 clock = TIOA1
+							| AT91C_TC_WAVE                 // Waveform Mode
+							| AT91C_TC_WAVESEL_UP           // just count
+							| AT91C_TC_ACPA_CLEAR           // Clear TIOA0 on RA Compare
+							| AT91C_TC_ACPC_SET;            // Set TIOA0 on RC Compare
+	AT91C_BASE_TC0->TC_RA = 1;                              // RA Compare value = 1; pulse width to TC2
+	AT91C_BASE_TC0->TC_RC = 0;                              // RC Compare value = 0; increment TC2 on overflow
 
 	// use TC2 to count TIOA0 pulses (giving us a 32bit counter (TC0/TC2) clocked by ssp_clk)
-	AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKDIS; 				// disable TC2  
-	AT91C_BASE_TC2->TC_CMR = AT91C_TC_CLKS_XC2	 			// TC2 clock = XC2 clock = TIOA0
-							| AT91C_TC_WAVE 				// Waveform Mode
-							| AT91C_TC_WAVESEL_UP;	 		// just count
-	
-	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;				// enable TC0
-	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN;				// enable TC1
-	AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN;				// enable TC2
+	AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKDIS;               // disable TC2
+	AT91C_BASE_TC2->TC_CMR = AT91C_TC_CLKS_XC2              // TC2 clock = XC2 clock = TIOA0
+							| AT91C_TC_WAVE                 // Waveform Mode
+							| AT91C_TC_WAVESEL_UP;          // just count
+
+	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;                // enable TC0
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN;                // enable TC1
+	AT91C_BASE_TC2->TC_CCR = AT91C_TC_CLKEN;                // enable TC2
 
 	//
-	// synchronize the counter with the ssp_frame signal. Note: FPGA must be in a FPGA mode with SSC transfer, otherwise SSC_FRAME and SSC_CLK signals would not be present 
+	// synchronize the counter with the ssp_frame signal. Note: FPGA must be in a FPGA mode with SSC transfer, otherwise SSC_FRAME and SSC_CLK signals would not be present
 	//
-	while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME)); 	// wait for ssp_frame to go high (start of frame)
-	while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME); 		// wait for ssp_frame to be low
-	while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); 	// wait for ssp_clk to go high
-	// note: up to now two ssp_clk rising edges have passed since the rising edge of ssp_frame
+	while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME);      // wait for ssp_frame to be low
+	while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_FRAME));   // wait for ssp_frame to go high (start of frame)
+	while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK));     // wait for ssp_clk to go high; 1st ssp_clk after start of frame
+	while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK);        // wait for ssp_clk to go low;
+	while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK));     // wait for ssp_clk to go high; 2nd ssp_clk after start of frame
+	if ((AT91C_BASE_SSC->SSC_RFMR & SSC_FRAME_MODE_BITS_IN_WORD(32)) == SSC_FRAME_MODE_BITS_IN_WORD(16)) {
+		while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK);    // wait for ssp_clk to go low;
+		while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 3rd ssp_clk after start of frame
+		while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK);    // wait for ssp_clk to go low;
+		while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 4th ssp_clk after start of frame
+		while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK);    // wait for ssp_clk to go low;
+		while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 5th ssp_clk after start of frame
+		while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK);    // wait for ssp_clk to go low;
+		while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)); // wait for ssp_clk to go high; 6th ssp_clk after start of frame
+	}
 	// it is now safe to assert a sync signal. This sets all timers to 0 on next active clock edge
-	AT91C_BASE_TCB->TCB_BCR = 1;							// assert Sync (set all timers to 0 on next active clock edge)
-	// at the next (3rd) ssp_clk rising edge, TC1 will be reset (and not generate a clock signal to TC0)
-	// at the next (4th) ssp_clk rising edge, TC0 (the low word of our counter) will be reset. From now on,
+	AT91C_BASE_TCB->TCB_BCR = 1;                            // assert Sync (set all timers to 0 on next active clock edge)
+	// at the next (3rd/7th) ssp_clk rising edge, TC1 will be reset (and not generate a clock signal to TC0)
+	// at the next (4th/8th) ssp_clk rising edge, TC0 (the low word of our counter) will be reset. From now on,
 	// whenever the last three bits of our counter go 0, we can be sure to be in the middle of a frame transfer.
-	// (just started with the transfer of the 4th Bit).
+	// (just started with the transfer of the 3rd Bit).
 	// The high word of the counter (TC2) will not reset until the low word (TC0) overflows. Therefore need to wait quite some time before
 	// we can use the counter.
 	while (AT91C_BASE_TC0->TC_CV < 0xFFFF);
@@ -445,19 +456,17 @@ void ResetSspClk(void) {
 	while (AT91C_BASE_TC2->TC_CV > 0);
 }
 
-
 uint32_t GetCountSspClk(){
 	uint32_t hi, lo;
 
-	do {
+	do { 
 		hi = AT91C_BASE_TC2->TC_CV;
 		lo = AT91C_BASE_TC0->TC_CV;
-	} while(hi != AT91C_BASE_TC2->TC_CV);
-
+	} while (hi != AT91C_BASE_TC2->TC_CV);
+	
 	return (hi << 16) | lo;
 }
 
-
 //  -------------------------------------------------------------------------
 //  Timer for bitbanging, or LF stuff when you need a very precis timer
 //  1us = 1.5ticks
@@ -476,11 +485,11 @@ void StartTicks(void){
 	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // re-enable timer and wait for TC0
 
 	// second configure TC0 (lower, 0x0000FFFF) 16 bit counter
-	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz) / 32 
-	                         AT91C_TC_WAVE | AT91C_TC_WAVESEL_UP_AUTO |
-	                         AT91C_TC_ACPA_CLEAR | // RA comperator clears TIOA (carry bit)
-	                         AT91C_TC_ACPC_SET |   // RC comperator sets TIOA (carry bit)
-	                         AT91C_TC_ASWTRG_SET;  // SWTriger sets TIOA (carry bit)
+	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK | // MCK(48MHz) / 32
+							 AT91C_TC_WAVE | AT91C_TC_WAVESEL_UP_AUTO |
+							 AT91C_TC_ACPA_CLEAR | // RA comperator clears TIOA (carry bit)
+							 AT91C_TC_ACPC_SET |   // RC comperator sets TIOA (carry bit)
+							 AT91C_TC_ASWTRG_SET;  // SWTriger sets TIOA (carry bit)
 	AT91C_BASE_TC0->TC_RC  = 0; // set TIOA (carry bit) on overflow, return to zero
 	AT91C_BASE_TC0->TC_RA  = 1; // clear carry bit on next clock cycle
 	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN | AT91C_TC_SWTRG; // reset and re-enable timer
@@ -517,7 +526,7 @@ void WaitTicks(uint32_t ticks){
 }
 
 
-// Wait / Spindelay in us (microseconds) 
+// Wait / Spindelay in us (microseconds)
 // 1us = 1.5ticks.
 void WaitUS(uint16_t us){
 	WaitTicks( (uint32_t)us * 3 / 2 ) ;
@@ -546,7 +555,7 @@ void ResetTimer(AT91PS_TC timer){
 // stop clock
 void StopTicks(void){
 	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS;
-	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;	
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
 }
 
 
diff --git a/armsrc/util.h b/armsrc/util.h
index 7b3d0849..14ac5e10 100644
--- a/armsrc/util.h
+++ b/armsrc/util.h
@@ -66,7 +66,7 @@ uint32_t RAMFUNC GetDeltaCountUS();
 
 void StartCountSspClk();
 void ResetSspClk(void);
-uint32_t RAMFUNC GetCountSspClk();
+uint32_t GetCountSspClk();
 
 extern void StartTicks(void);
 extern uint32_t GetTicks(void);
diff --git a/client/cmdhf15.c b/client/cmdhf15.c
index c2a13354..6bcad201 100644
--- a/client/cmdhf15.c
+++ b/client/cmdhf15.c
@@ -464,7 +464,7 @@ int CmdHF15CmdRaw (const char *cmd) {
 	char *hexout;
 
 	
-	if (strlen(cmd)<3) {
+	if (strlen(cmd)<2) {
 		PrintAndLog("Usage: hf 15 cmd raw  [-r] [-2] [-c] <0A 0B 0C ... hex>");
 		PrintAndLog("       -r    do not read response");
 		PrintAndLog("       -2    use slower '1 out of 256' mode");
@@ -526,22 +526,31 @@ int CmdHF15CmdRaw (const char *cmd) {
 	SendCommand(&c);
 	
 	if (reply) {
-		if (WaitForResponseTimeout(CMD_ACK,&resp,1000)) {
+		if (WaitForResponseTimeout(CMD_ACK, &resp, 1000)) {
 			recv = resp.d.asBytes;
-			PrintAndLog("received %i octets",resp.arg[0]);
-			hexout = (char *)malloc(resp.arg[0] * 3 + 1);
-			if (hexout != NULL) {
-				for (int i = 0; i < resp.arg[0]; i++) { // data in hex
-					sprintf(&hexout[i * 3], "%02X ", recv[i]);
+			int recv_len = resp.arg[0];
+			if (recv_len == 0) {
+				PrintAndLog("received SOF only. Maybe Picopass/iCLASS?");
+			} else if (recv_len > 0) {
+				PrintAndLog("received %i octets", recv_len);
+				hexout = (char *)malloc(resp.arg[0] * 3 + 1);
+				if (hexout != NULL) {
+					for (int i = 0; i < resp.arg[0]; i++) { // data in hex
+						sprintf(&hexout[i * 3], "%02X ", recv[i]);
+					}
+					PrintAndLog("%s", hexout);
+					free(hexout);
 				}
-				PrintAndLog("%s", hexout);
-				free(hexout);
+			} else if (recv_len == -1) {
+				PrintAndLog("card didn't respond");
+			} else if (recv_len == -2) {
+				PrintAndLog("receive buffer overflow");
 			}
 		} else {
 			PrintAndLog("timeout while waiting for reply.");
 		}
-		
-	} // if reply
+	}
+
 	return 0;
 }
 
diff --git a/client/cmdhflist.c b/client/cmdhflist.c
index 07a286cc..29d10d92 100644
--- a/client/cmdhflist.c
+++ b/client/cmdhflist.c
@@ -903,8 +903,6 @@ uint16_t printTraceLine(uint16_t tracepos, uint16_t traceLen, uint8_t *trace, ui
 
 	// adjust for different time scales
 	if (protocol == ICLASS || protocol == ISO_15693) {
-		first_timestamp *= 32;
-		timestamp *= 32;
 		duration *= 32;
 	}
 
@@ -1037,10 +1035,6 @@ uint16_t printTraceLine(uint16_t tracepos, uint16_t traceLen, uint8_t *trace, ui
 
 	if (showWaitCycles && !isResponse && next_record_is_response(tracepos, trace)) {
 		uint32_t next_timestamp = *((uint32_t *)(trace + tracepos));
-		// adjust for different time scales
-		if (protocol == ICLASS || protocol == ISO_15693) {
-			next_timestamp *= 32;
-		}
 
 		PrintAndLog(" %10d | %10d | %s | fdt (Frame Delay Time): %d",
 			(EndOfTransmissionTimestamp - first_timestamp),
diff --git a/fpga/fpga_hf.bit b/fpga/fpga_hf.bit
index 44b24280..38990597 100644
Binary files a/fpga/fpga_hf.bit and b/fpga/fpga_hf.bit differ
diff --git a/fpga/hi_reader.v b/fpga/hi_reader.v
index b0b21e30..aca9132f 100644
--- a/fpga/hi_reader.v
+++ b/fpga/hi_reader.v
@@ -247,9 +247,9 @@ begin
 
 	// set ssp_frame signal for corr_i_cnt = 1..3
 	// (send one frame with 16 Bits)
-    if (corr_i_cnt == 6'd2)
+    if (corr_i_cnt == 6'd1)
         ssp_frame <= 1'b1;
-    if (corr_i_cnt == 6'd14)
+    if (corr_i_cnt == 6'd5)
         ssp_frame <= 1'b0;
 end