X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/6949aca9fa0e37539fc277bac78e3d7a22117467..3783c45af1ec1f478c3f17e8d75522a3043ad955:/armsrc/iso15693.c?ds=sidebyside

diff --git a/armsrc/iso15693.c b/armsrc/iso15693.c
index 723d297d..9dc4bf18 100644
--- a/armsrc/iso15693.c
+++ b/armsrc/iso15693.c
@@ -1,1190 +1,1752 @@
-//-----------------------------------------------------------------------------
-// Routines to support ISO 15693. This includes both the reader software and
-// the `fake tag' modes, but at the moment I've implemented only the reader
-// stuff, and that barely.
-// Jonathan Westhues, split Nov 2006
-
-// Modified by Greg Jones, Jan 2009 to perform modulation onboard in arm rather than on PC
-// Also added additional reader commands (SELECT, READ etc.)
-
-//-----------------------------------------------------------------------------
-#include <proxmark3.h>
-#include "apps.h"
-#include <stdio.h>
-#include <stdlib.h>
-
-// FROM winsrc\prox.h //////////////////////////////////
-#define arraylen(x) (sizeof(x)/sizeof((x)[0]))
-
-//-----------------------------------------------------------------------------
-// Map a sequence of octets (~layer 2 command) into the set of bits to feed
-// to the FPGA, to transmit that command to the tag.
-//-----------------------------------------------------------------------------
-
-	// The sampling rate is 106.353 ksps/s, for T = 18.8 us
-
-	// SOF defined as
-	// 1) Unmodulated time of 56.64us
-	// 2) 24 pulses of 423.75khz
-	// 3) logic '1' (unmodulated for 18.88us followed by 8 pulses of 423.75khz)
-
-	static const int FrameSOF[] = {
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		-1, -1, -1, -1,
-		-1, -1, -1, -1,
-		 1,  1,  1,  1,
-		 1,  1,  1,  1
-	};
-	static const int Logic0[] = {
-		 1,  1,  1,  1,
-		 1,  1,  1,  1,
-		-1, -1, -1, -1,
-		-1, -1, -1, -1
-	};
-	static const int Logic1[] = {
-		-1, -1, -1, -1,
-		-1, -1, -1, -1,
-		 1,  1,  1,  1,
-		 1,  1,  1,  1
-	};
-
-	// EOF defined as
-	// 1) logic '0' (8 pulses of 423.75khz followed by unmodulated for 18.88us)
-	// 2) 24 pulses of 423.75khz
-	// 3) Unmodulated time of 56.64us
-
-	static const int FrameEOF[] = {
-		 1,  1,  1,  1,
-		 1,  1,  1,  1,
-		-1, -1, -1, -1,
-		-1, -1, -1, -1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		 1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,  1,
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-		-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
-	};
-
-static void CodeIso15693AsReader(BYTE *cmd, int n)
-{
-	int i, j;
-
-	ToSendReset();
-
-	// Give it a bit of slack at the beginning
-	for(i = 0; i < 24; i++) {
-		ToSendStuffBit(1);
-	}
-
-	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;
-			switch(these) {
-				case 0:
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					break;
-				case 1:
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					break;
-				case 2:
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					break;
-				case 3:
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(1);
-					ToSendStuffBit(0);
-					break;
-			}
-		}
-	}
-	ToSendStuffBit(1);
-	ToSendStuffBit(1);
-	ToSendStuffBit(0);
-	ToSendStuffBit(1);
-
-	// And slack at the end, too.
-	for(i = 0; i < 24; i++) {
-		ToSendStuffBit(1);
-	}
-}
-
-//-----------------------------------------------------------------------------
-// The CRC used by ISO 15693.
-//-----------------------------------------------------------------------------
-static WORD Crc(BYTE *v, int n)
-{
-	DWORD reg;
-	int i, j;
-
-	reg = 0xffff;
-	for(i = 0; i < n; i++) {
-		reg = reg ^ ((DWORD)v[i]);
-		for (j = 0; j < 8; j++) {
-			if (reg & 0x0001) {
-				reg = (reg >> 1) ^ 0x8408;
-			} else {
-				reg = (reg >> 1);
-			}
-		}
-	}
-
-	return ~reg;
-}
-
-char *strcat(char *dest, const char *src)
-{
-	size_t dest_len = strlen(dest);
-	size_t i;
- 
-	for (i = 0 ; src[i] != '\0' ; i++)
-	        dest[dest_len + i] = src[i];
-	dest[dest_len + i] = '\0';
- 
-	return dest;
-}
-
-////////////////////////////////////////// code to do 'itoa'
-
-/* reverse:  reverse string s in place */
-void reverse(char s[])
-{
-    int c, i, j;
-
-    for (i = 0, j = strlen(s)-1; i<j; i++, j--) {
-        c = s[i];
-        s[i] = s[j];
-        s[j] = c;
-    }
-}
-
-/* itoa:  convert n to characters in s */
-void itoa(int n, char s[])
-{
-    int i, sign;
-
-    if ((sign = n) < 0)  /* record sign */
-        n = -n;          /* make n positive */
-    i = 0;
-    do {       /* generate digits in reverse order */
-        s[i++] = n % 10 + '0';   /* get next digit */
-    } while ((n /= 10) > 0);     /* delete it */
-    if (sign < 0)
-        s[i++] = '-';
-    s[i] = '\0';
-    reverse(s);
-}
-
-//////////////////////////////////////// END 'itoa' CODE
-
-//-----------------------------------------------------------------------------
-// Encode (into the ToSend buffers) an identify request, which is the first
-// thing that you must send to a tag to get a response.
-//-----------------------------------------------------------------------------
-static void BuildIdentifyRequest(void)
-{
-	BYTE cmd[5];
-
-	WORD crc;
-	// one sub-carrier, inventory, 1 slot, fast rate
-	// AFI is at bit 5 (1<<4) when doing an INVENTORY
-	cmd[0] = (1 << 2) | (1 << 5) | (1 << 1);
-	// inventory command code
-	cmd[1] = 0x01;
-	// no mask
-	cmd[2] = 0x00;
-	//Now the CRC
-	crc = Crc(cmd, 3);
-	cmd[3] = crc & 0xff;
-	cmd[4] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-static void __attribute__((unused)) BuildSysInfoRequest(BYTE *uid)
-{
-	BYTE cmd[12];
-
-	WORD crc;
-	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
-	// followed by teh block data
-	// one sub-carrier, inventory, 1 slot, fast rate
-	cmd[0] =  (1 << 5) | (1 << 1); // no SELECT bit
-	// System Information command code
-	cmd[1] = 0x2B;
-	// UID may be optionally specified here
-	// 64-bit UID
-	cmd[2] = 0x32;
-	cmd[3]= 0x4b;
-	cmd[4] = 0x03;
-	cmd[5] = 0x01;
-	cmd[6] = 0x00;
-	cmd[7] = 0x10;
-	cmd[8] = 0x05;
-	cmd[9]= 0xe0; // always e0 (not exactly unique)
-	//Now the CRC
-	crc = Crc(cmd, 10); // the crc needs to be calculated over 2 bytes
-	cmd[10] = crc & 0xff;
-	cmd[11] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-static void BuildSelectRequest( BYTE uid[])
-{
-
-//	uid[6]=0x31;  // this is getting ignored - the uid array is not happening...
-	BYTE cmd[12];
-
-	WORD crc;
-	// one sub-carrier, inventory, 1 slot, fast rate
-	//cmd[0] = (1 << 2) | (1 << 5) | (1 << 1);	// INVENTROY FLAGS
-	cmd[0] = (1 << 4) | (1 << 5) | (1 << 1);	// Select and addressed FLAGS
-	// SELECT command code
-	cmd[1] = 0x25;
-	// 64-bit UID
-//	cmd[2] = uid[0];//0x32;
-//	cmd[3]= uid[1];//0x4b;
-//	cmd[4] = uid[2];//0x03;
-//	cmd[5] = uid[3];//0x01;
-//	cmd[6] = uid[4];//0x00;
-//	cmd[7] = uid[5];//0x10;
-//	cmd[8] = uid[6];//0x05;
-	cmd[2] = 0x32;//
-	cmd[3] = 0x4b;
-	cmd[4] = 0x03;
-	cmd[5] = 0x01;
-	cmd[6] = 0x00;
-	cmd[7] = 0x10;
-	cmd[8] = 0x05; // infineon?
-
-	cmd[9]= 0xe0; // always e0 (not exactly unique)
-
-//	DbpIntegers(cmd[8],cmd[7],cmd[6]);
-	// Now the CRC
-	crc = Crc(cmd, 10); // the crc needs to be calculated over 10 bytes
-	cmd[10] = crc & 0xff;
-	cmd[11] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-static void __attribute__((unused)) BuildReadBlockRequest(BYTE *uid, BYTE blockNumber )
-{
-	BYTE cmd[13];
-
-	WORD crc;
-	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
-	// followed by teh block data
-	// one sub-carrier, inventory, 1 slot, fast rate
-	cmd[0] = (1 << 6)| (1 << 5) | (1 << 1); // no SELECT bit
-	// READ BLOCK command code
-	cmd[1] = 0x20;
-	// UID may be optionally specified here
-	// 64-bit UID
-	cmd[2] = 0x32;
-	cmd[3]= 0x4b;
-	cmd[4] = 0x03;
-	cmd[5] = 0x01;
-	cmd[6] = 0x00;
-	cmd[7] = 0x10;
-	cmd[8] = 0x05;
-	cmd[9]= 0xe0; // always e0 (not exactly unique)
-	// Block number to read
-	cmd[10] = blockNumber;//0x00;
-	//Now the CRC
-	crc = Crc(cmd, 11); // the crc needs to be calculated over 2 bytes
-	cmd[11] = crc & 0xff;
-	cmd[12] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-static void __attribute__((unused)) BuildReadMultiBlockRequest(BYTE *uid)
-{
-	BYTE cmd[14];
-
-	WORD crc;
-	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
-	// followed by teh block data
-	// one sub-carrier, inventory, 1 slot, fast rate
-	cmd[0] =  (1 << 5) | (1 << 1); // no SELECT bit
-	// READ Multi BLOCK command code
-	cmd[1] = 0x23;
-	// UID may be optionally specified here
-	// 64-bit UID
-	cmd[2] = 0x32;
-	cmd[3]= 0x4b;
-	cmd[4] = 0x03;
-	cmd[5] = 0x01;
-	cmd[6] = 0x00;
-	cmd[7] = 0x10;
-	cmd[8] = 0x05;
-	cmd[9]= 0xe0; // always e0 (not exactly unique)
-	// First Block number to read
-	cmd[10] = 0x00;
-	// Number of Blocks to read
-	cmd[11] = 0x2f; // read quite a few
-	//Now the CRC
-	crc = Crc(cmd, 12); // the crc needs to be calculated over 2 bytes
-	cmd[12] = crc & 0xff;
-	cmd[13] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-static void __attribute__((unused)) BuildArbitraryRequest(BYTE *uid,BYTE CmdCode)
-{
-	BYTE cmd[14];
-
-	WORD crc;
-	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
-	// followed by teh block data
-	// one sub-carrier, inventory, 1 slot, fast rate
-	cmd[0] =   (1 << 5) | (1 << 1); // no SELECT bit
-	// READ BLOCK command code
-	cmd[1] = CmdCode;
-	// UID may be optionally specified here
-	// 64-bit UID
-	cmd[2] = 0x32;
-	cmd[3]= 0x4b;
-	cmd[4] = 0x03;
-	cmd[5] = 0x01;
-	cmd[6] = 0x00;
-	cmd[7] = 0x10;
-	cmd[8] = 0x05;
-	cmd[9]= 0xe0; // always e0 (not exactly unique)
-	// Parameter
-	cmd[10] = 0x00;
-	cmd[11] = 0x0a;
-
-//	cmd[12] = 0x00;
-//	cmd[13] = 0x00;	//Now the CRC
-	crc = Crc(cmd, 12); // the crc needs to be calculated over 2 bytes
-	cmd[12] = crc & 0xff;
-	cmd[13] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-static void __attribute__((unused)) BuildArbitraryCustomRequest(BYTE uid[], BYTE CmdCode)
-{
-	BYTE cmd[14];
-
-	WORD crc;
-	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
-	// followed by teh block data
-	// one sub-carrier, inventory, 1 slot, fast rate
-	cmd[0] =   (1 << 5) | (1 << 1); // no SELECT bit
-	// READ BLOCK command code
-	cmd[1] = CmdCode;
-	// UID may be optionally specified here
-	// 64-bit UID
-	cmd[2] = 0x32;
-	cmd[3]= 0x4b;
-	cmd[4] = 0x03;
-	cmd[5] = 0x01;
-	cmd[6] = 0x00;
-	cmd[7] = 0x10;
-	cmd[8] = 0x05;
-	cmd[9]= 0xe0; // always e0 (not exactly unique)
-	// Parameter
-	cmd[10] = 0x05; // for custom codes this must be manufcturer code
-	cmd[11] = 0x00;
-
-//	cmd[12] = 0x00;
-//	cmd[13] = 0x00;	//Now the CRC
-	crc = Crc(cmd, 12); // the crc needs to be calculated over 2 bytes
-	cmd[12] = crc & 0xff;
-	cmd[13] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-/////////////////////////////////////////////////////////////////////////
-// Now the VICC>VCD responses when we are simulating a tag
-////////////////////////////////////////////////////////////////////
-
- static void BuildInventoryResponse(void)
-{
-	BYTE cmd[12];
-
-	WORD crc;
-	// one sub-carrier, inventory, 1 slot, fast rate
-	// AFI is at bit 5 (1<<4) when doing an INVENTORY
-	cmd[0] = 0; //(1 << 2) | (1 << 5) | (1 << 1);
-	cmd[1] = 0;
-	// 64-bit UID
-	cmd[2] = 0x32;
-	cmd[3]= 0x4b;
-	cmd[4] = 0x03;
-	cmd[5] = 0x01;
-	cmd[6] = 0x00;
-	cmd[7] = 0x10;
-	cmd[8] = 0x05;
-	cmd[9]= 0xe0;
-	//Now the CRC
-	crc = Crc(cmd, 10);
-	cmd[10] = crc & 0xff;
-	cmd[11] = crc >> 8;
-
-	CodeIso15693AsReader(cmd, sizeof(cmd));
-}
-
-//-----------------------------------------------------------------------------
-// Transmit the command (to the tag) that was placed in ToSend[].
-//-----------------------------------------------------------------------------
-static void TransmitTo15693Tag(const BYTE *cmd, int len, int *samples, int *wait)
-{
-    int c;
-
-//    FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_READER_MOD);
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
-	if(*wait < 10) { *wait = 10; }
-
-//    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 DWORD r = AT91C_BASE_SSC->SSC_RHR;
-//            (void)r;
-//        }
-//        WDT_HIT();
-//    }
-
-    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 DWORD r = AT91C_BASE_SSC->SSC_RHR;
-            (void)r;
-        }
-        WDT_HIT();
-    }
-	*samples = (c + *wait) << 3;
-}
-
-//-----------------------------------------------------------------------------
-// Transmit the command (to the reader) that was placed in ToSend[].
-//-----------------------------------------------------------------------------
-static void TransmitTo15693Reader(const BYTE *cmd, int len, int *samples, int *wait)
-{
-    int c;
-
-//	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR);	// No requirement to energise my coils
-	if(*wait < 10) { *wait = 10; }
-
-    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 DWORD r = AT91C_BASE_SSC->SSC_RHR;
-            (void)r;
-        }
-        WDT_HIT();
-    }
-	*samples = (c + *wait) << 3;
-}
-
-static int GetIso15693AnswerFromTag(BYTE *receivedResponse, int maxLen, int *samples, int *elapsed)
-{
-	int c = 0;
-	BYTE *dest = (BYTE *)BigBuf;
-	int getNext = 0;
-
-	SBYTE prev = 0;
-
-// NOW READ RESPONSE
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
-	//spindelay(60);	// greg - experiment to get rid of some of the 0 byte/failed reads
-	c = 0;
-	getNext = FALSE;
-	for(;;) {
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-			AT91C_BASE_SSC->SSC_THR = 0x43;
-		}
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-			SBYTE b;
-			b = (SBYTE)AT91C_BASE_SSC->SSC_RHR;
-
-			// The samples are correlations against I and Q versions of the
-			// tone that the tag AM-modulates, so every other sample is I,
-			// every other is Q. We just want power, so abs(I) + abs(Q) is
-			// close to what we want.
-			if(getNext) {
-				SBYTE r;
-
-				if(b < 0) {
-					r = -b;
-				} else {
-					r = b;
-				}
-				if(prev < 0) {
-					r -= prev;
-				} else {
-					r += prev;
-				}
-
-				dest[c++] = (BYTE)r;
-
-				if(c >= 2000) {
-					break;
-				}
-			} else {
-				prev = b;
-			}
-
-			getNext = !getNext;
-		}
-	}
-
-//////////////////////////////////////////
-/////////// DEMODULATE ///////////////////
-//////////////////////////////////////////
-
-	int i, j;
-	int max = 0, maxPos=0;
-
-	int skip = 4;
-
-//	if(GraphTraceLen < 1000) return;	// THIS CHECKS FOR A BUFFER TO SMALL
-
-	// First, correlate for SOF
-	for(i = 0; i < 100; i++) {
-		int corr = 0;
-		for(j = 0; j < arraylen(FrameSOF); j += skip) {
-			corr += FrameSOF[j]*dest[i+(j/skip)];
-		}
-		if(corr > max) {
-			max = corr;
-			maxPos = i;
-		}
-	}
-//	DbpString("SOF at %d, correlation %d", maxPos,max/(arraylen(FrameSOF)/skip));
-
-	int k = 0; // this will be our return value
-
-	// greg - If correlation is less than 1 then there's little point in continuing
-	if ((max/(arraylen(FrameSOF)/skip)) >= 1)
-	{
-
-	i = maxPos + arraylen(FrameSOF)/skip;
-
-	BYTE outBuf[20];
-	memset(outBuf, 0, sizeof(outBuf));
-	BYTE mask = 0x01;
-	for(;;) {
-		int corr0 = 0, corr1 = 0, corrEOF = 0;
-		for(j = 0; j < arraylen(Logic0); j += skip) {
-			corr0 += Logic0[j]*dest[i+(j/skip)];
-		}
-		for(j = 0; j < arraylen(Logic1); j += skip) {
-			corr1 += Logic1[j]*dest[i+(j/skip)];
-		}
-		for(j = 0; j < arraylen(FrameEOF); j += skip) {
-			corrEOF += FrameEOF[j]*dest[i+(j/skip)];
-		}
-		// Even things out by the length of the target waveform.
-		corr0 *= 4;
-		corr1 *= 4;
-
-		if(corrEOF > corr1 && corrEOF > corr0) {
-//			DbpString("EOF at %d", i);
-			break;
-		} else if(corr1 > corr0) {
-			i += arraylen(Logic1)/skip;
-			outBuf[k] |= mask;
-		} else {
-			i += arraylen(Logic0)/skip;
-		}
-		mask <<= 1;
-		if(mask == 0) {
-			k++;
-			mask = 0x01;
-		}
-		if((i+(int)arraylen(FrameEOF)) >= 2000) {
-			DbpString("ran off end!");
-			break;
-		}
-	}
-	if(mask != 0x01) {
-		DbpString("error, uneven octet! (discard extra bits!)");
-///		DbpString("   mask=%02x", mask);
-	}
-//	BYTE str1 [8];
-//	itoa(k,str1);
-//	strcat(str1," octets read");
-
-//	DbpString(  str1);    // DbpString("%d octets", k);
-
-//	for(i = 0; i < k; i+=3) {
-//		//DbpString("# %2d: %02x ", i, outBuf[i]);
-//		DbpIntegers(outBuf[i],outBuf[i+1],outBuf[i+2]);
-//	}
-
-	for(i = 0; i < k; i++) {
-		receivedResponse[i] = outBuf[i];
-	}
-	} // "end if correlation > 0" 	(max/(arraylen(FrameSOF)/skip))
-	return k; // return the number of bytes demodulated
-
-///	DbpString("CRC=%04x", Iso15693Crc(outBuf, k-2));
-
-}
-
-// Now the GetISO15693 message from sniffing command
-static int GetIso15693AnswerFromSniff(BYTE *receivedResponse, int maxLen, int *samples, int *elapsed)
-{
-	int c = 0;
-	BYTE *dest = (BYTE *)BigBuf;
-	int getNext = 0;
-
-	SBYTE prev = 0;
-
-// NOW READ RESPONSE
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
-	//spindelay(60);	// greg - experiment to get rid of some of the 0 byte/failed reads
-	c = 0;
-	getNext = FALSE;
-	for(;;) {
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-			AT91C_BASE_SSC->SSC_THR = 0x43;
-		}
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-			SBYTE b;
-			b = (SBYTE)AT91C_BASE_SSC->SSC_RHR;
-
-			// The samples are correlations against I and Q versions of the
-			// tone that the tag AM-modulates, so every other sample is I,
-			// every other is Q. We just want power, so abs(I) + abs(Q) is
-			// close to what we want.
-			if(getNext) {
-				SBYTE r;
-
-				if(b < 0) {
-					r = -b;
-				} else {
-					r = b;
-				}
-				if(prev < 0) {
-					r -= prev;
-				} else {
-					r += prev;
-				}
-
-				dest[c++] = (BYTE)r;
-
-				if(c >= 20000) {
-					break;
-				}
-			} else {
-				prev = b;
-			}
-
-			getNext = !getNext;
-		}
-	}
-
-//////////////////////////////////////////
-/////////// DEMODULATE ///////////////////
-//////////////////////////////////////////
-
-	int i, j;
-	int max = 0, maxPos=0;
-
-	int skip = 4;
-
-//	if(GraphTraceLen < 1000) return;	// THIS CHECKS FOR A BUFFER TO SMALL
-
-	// First, correlate for SOF
-	for(i = 0; i < 19000; i++) {
-		int corr = 0;
-		for(j = 0; j < arraylen(FrameSOF); j += skip) {
-			corr += FrameSOF[j]*dest[i+(j/skip)];
-		}
-		if(corr > max) {
-			max = corr;
-			maxPos = i;
-		}
-	}
-//	DbpString("SOF at %d, correlation %d", maxPos,max/(arraylen(FrameSOF)/skip));
-
-	int k = 0; // this will be our return value
-
-	// greg - If correlation is less than 1 then there's little point in continuing
-	if ((max/(arraylen(FrameSOF)/skip)) >= 1)	// THIS SHOULD BE 1
-	{
-
-	i = maxPos + arraylen(FrameSOF)/skip;
-
-	BYTE outBuf[20];
-	memset(outBuf, 0, sizeof(outBuf));
-	BYTE mask = 0x01;
-	for(;;) {
-		int corr0 = 0, corr1 = 0, corrEOF = 0;
-		for(j = 0; j < arraylen(Logic0); j += skip) {
-			corr0 += Logic0[j]*dest[i+(j/skip)];
-		}
-		for(j = 0; j < arraylen(Logic1); j += skip) {
-			corr1 += Logic1[j]*dest[i+(j/skip)];
-		}
-		for(j = 0; j < arraylen(FrameEOF); j += skip) {
-			corrEOF += FrameEOF[j]*dest[i+(j/skip)];
-		}
-		// Even things out by the length of the target waveform.
-		corr0 *= 4;
-		corr1 *= 4;
-
-		if(corrEOF > corr1 && corrEOF > corr0) {
-//			DbpString("EOF at %d", i);
-			break;
-		} else if(corr1 > corr0) {
-			i += arraylen(Logic1)/skip;
-			outBuf[k] |= mask;
-		} else {
-			i += arraylen(Logic0)/skip;
-		}
-		mask <<= 1;
-		if(mask == 0) {
-			k++;
-			mask = 0x01;
-		}
-		if((i+(int)arraylen(FrameEOF)) >= 2000) {
-			DbpString("ran off end!");
-			break;
-		}
-	}
-	if(mask != 0x01) {
-		DbpString("error, uneven octet! (discard extra bits!)");
-///		DbpString("   mask=%02x", mask);
-	}
-//	BYTE str1 [8];
-//	itoa(k,str1);
-//	strcat(str1," octets read");
-
-//	DbpString(  str1);    // DbpString("%d octets", k);
-
-//	for(i = 0; i < k; i+=3) {
-//		//DbpString("# %2d: %02x ", i, outBuf[i]);
-//		DbpIntegers(outBuf[i],outBuf[i+1],outBuf[i+2]);
-//	}
-
-	for(i = 0; i < k; i++) {
-		receivedResponse[i] = outBuf[i];
-	}
-	} // "end if correlation > 0" 	(max/(arraylen(FrameSOF)/skip))
-	return k; // return the number of bytes demodulated
-
-///	DbpString("CRC=%04x", Iso15693Crc(outBuf, k-2));
-}
-
-//-----------------------------------------------------------------------------
-// Start to read an ISO 15693 tag. We send an identify request, then wait
-// for the response. The response is not demodulated, just left in the buffer
-// so that it can be downloaded to a PC and processed there.
-//-----------------------------------------------------------------------------
-void AcquireRawAdcSamplesIso15693(void)
-{
-	int c = 0;
-	BYTE *dest = (BYTE *)BigBuf;
-	int getNext = 0;
-
-	SBYTE prev = 0;
-
-	BuildIdentifyRequest();
-
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-
-	// Give the tags time to energize
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
-	SpinDelay(100);
-
-	// Now send the command
-	FpgaSetupSsc();
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
-
-	c = 0;
-	for(;;) {
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-			AT91C_BASE_SSC->SSC_THR = ToSend[c];
-			c++;
-			if(c == ToSendMax+3) {
-				break;
-			}
-		}
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-			volatile DWORD r = AT91C_BASE_SSC->SSC_RHR;
-			(void)r;
-		}
-		WDT_HIT();
-	}
-
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
-
-	c = 0;
-	getNext = FALSE;
-	for(;;) {
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-			AT91C_BASE_SSC->SSC_THR = 0x43;
-		}
-		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-			SBYTE b;
-			b = (SBYTE)AT91C_BASE_SSC->SSC_RHR;
-
-			// The samples are correlations against I and Q versions of the
-			// tone that the tag AM-modulates, so every other sample is I,
-			// every other is Q. We just want power, so abs(I) + abs(Q) is
-			// close to what we want.
-			if(getNext) {
-				SBYTE r;
-
-				if(b < 0) {
-					r = -b;
-				} else {
-					r = b;
-				}
-				if(prev < 0) {
-					r -= prev;
-				} else {
-					r += prev;
-				}
-
-				dest[c++] = (BYTE)r;
-
-				if(c >= 2000) {
-					break;
-				}
-			} else {
-				prev = b;
-			}
-
-			getNext = !getNext;
-		}
-	}
-}
-
-//-----------------------------------------------------------------------------
-// Simulate an ISO15693 reader, perform anti-collision and then attempt to read a sector
-// all demodulation performed in arm rather than host. - greg
-//-----------------------------------------------------------------------------
-void ReaderIso15693(DWORD parameter)
-{
-	LED_A_ON();
-	LED_B_ON();
-	LED_C_OFF();
-	LED_D_OFF();
-
-//DbpString(parameter);
-
-	BYTE *receivedAnswer0 = (((BYTE *)BigBuf) + 3560); // allow 100 bytes per reponse (way too much)
-	BYTE *receivedAnswer1 = (((BYTE *)BigBuf) + 3660); //
-	BYTE *receivedAnswer2 = (((BYTE *)BigBuf) + 3760);
-	BYTE *receivedAnswer3 = (((BYTE *)BigBuf) + 3860);
-	//BYTE *TagUID= (((BYTE *)BigBuf) + 3960);		// where we hold the uid for hi15reader
-//	int responseLen0 = 0;
-	int responseLen1 = 0;
-	int responseLen2 = 0;
-	int responseLen3 = 0;
-
-	// Blank arrays
-	int j;
-	for(j = 0; j < 100; j++) {
-		receivedAnswer3[j] = 0;
-		receivedAnswer2[j] =0;
-		receivedAnswer1[j] = 0;
-		receivedAnswer0[j] = 0;
-	}
-
-	// Setup SSC
-	FpgaSetupSsc();
-
-	// Start from off (no field generated)
-    	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-    	SpinDelay(200);
-
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-	FpgaSetupSsc();
-
-	// Give the tags time to energize
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
-	SpinDelay(200);
-
-	LED_A_ON();
-	LED_B_OFF();
-	LED_C_OFF();
-	LED_D_OFF();
-
-	int samples = 0;
-	int tsamples = 0;
-	int wait = 0;
-	int elapsed = 0;
-
-	// FIRST WE RUN AN INVENTORY TO GET THE TAG UID
-	// THIS MEANS WE CAN PRE-BUILD REQUESTS TO SAVE CPU TIME
- BYTE TagUID[7];		// where we hold the uid for hi15reader
-
-//	BuildIdentifyRequest();
-//	//TransmitTo15693Tag(ToSend,ToSendMax+3,&tsamples, &wait);
-//	TransmitTo15693Tag(ToSend,ToSendMax,&tsamples, &wait);	// No longer ToSendMax+3
-//	// Now wait for a response
-//	responseLen0 = GetIso15693AnswerFromTag(receivedAnswer0, 100, &samples, &elapsed) ;
-//	if (responseLen0 >=12) // we should do a better check than this
-//	{
-//		// really we should check it is a valid mesg
-//		// but for now just grab what we think is the uid
-//		TagUID[0] = receivedAnswer0[2];
-//		TagUID[1] = receivedAnswer0[3];
-//		TagUID[2] = receivedAnswer0[4];
-//		TagUID[3] = receivedAnswer0[5];
-//		TagUID[4] = receivedAnswer0[6];
-//		TagUID[5] = receivedAnswer0[7];
-//		TagUID[6] = receivedAnswer0[8]; // IC Manufacturer code
-//	DbpIntegers(TagUID[6],TagUID[5],TagUID[4]);
-//}
-
-	// Now send the IDENTIFY command
-	BuildIdentifyRequest();
-	//TransmitTo15693Tag(ToSend,ToSendMax+3,&tsamples, &wait);
-	TransmitTo15693Tag(ToSend,ToSendMax,&tsamples, &wait);	// No longer ToSendMax+3
-	// Now wait for a response
-	responseLen1 = GetIso15693AnswerFromTag(receivedAnswer1, 100, &samples, &elapsed) ;
-
-	if (responseLen1 >=12) // we should do a better check than this
-	{
-
-		TagUID[0] = receivedAnswer1[2];
-		TagUID[1] = receivedAnswer1[3];
-		TagUID[2] = receivedAnswer1[4];
-		TagUID[3] = receivedAnswer1[5];
-		TagUID[4] = receivedAnswer1[6];
-		TagUID[5] = receivedAnswer1[7];
-		TagUID[6] = receivedAnswer1[8]; // IC Manufacturer code
-
-		// Now send the SELECT command
-		BuildSelectRequest(TagUID);
-		TransmitTo15693Tag(ToSend,ToSendMax,&tsamples, &wait);	// No longer ToSendMax+3
-		// Now wait for a response
-		responseLen2 = GetIso15693AnswerFromTag(receivedAnswer2, 100, &samples, &elapsed);
-
-		// Now send the MULTI READ command
-//		BuildArbitraryRequest(*TagUID,parameter);
-		BuildArbitraryCustomRequest(TagUID,parameter);
-//		BuildReadBlockRequest(*TagUID,parameter);
-//		BuildSysInfoRequest(*TagUID);
-		//TransmitTo15693Tag(ToSend,ToSendMax+3,&tsamples, &wait);
-		TransmitTo15693Tag(ToSend,ToSendMax,&tsamples, &wait);	// No longer ToSendMax+3
-		// Now wait for a response
-		responseLen3 = GetIso15693AnswerFromTag(receivedAnswer3, 100, &samples, &elapsed) ;
-
-	}
-
-	char str1 [4];
-	//char str2 [200];
-	int i;
-
-	itoa(responseLen1,str1);
-	strcat(str1," octets read from IDENTIFY request");
-	DbpString(str1);
-	for(i = 0; i < responseLen1; i+=3) {
-		DbpIntegers(receivedAnswer1[i],receivedAnswer1[i+1],receivedAnswer1[i+2]);
-	}
-
-	itoa(responseLen2,str1);
-	strcat(str1," octets read from SELECT request");
-	DbpString(str1);
-	for(i = 0; i < responseLen2; i+=3) {
-		DbpIntegers(receivedAnswer2[i],receivedAnswer2[i+1],receivedAnswer2[i+2]);
-	}
-
-	itoa(responseLen3,str1);
-	strcat(str1," octets read from XXX request");
-	DbpString(str1);
-	for(i = 0; i < responseLen3; i+=3) {
-		DbpIntegers(receivedAnswer3[i],receivedAnswer3[i+1],receivedAnswer3[i+2]);
-	}
-
-//	str2[0]=0;
-//	for(i = 0; i < responseLen3; i++) {
-//		itoa(str1,receivedAnswer3[i]);
-//		strcat(str2,str1);
-//	}
-//	DbpString(str2);
-
-	LED_A_OFF();
-	LED_B_OFF();
-	LED_C_OFF();
-	LED_D_OFF();
-}
-
-//-----------------------------------------------------------------------------
-// Simulate an ISO15693 TAG, perform anti-collision and then print any reader commands
-// all demodulation performed in arm rather than host. - greg
-//-----------------------------------------------------------------------------
-void SimTagIso15693(DWORD parameter)
-{
-	LED_A_ON();
-	LED_B_ON();
-	LED_C_OFF();
-	LED_D_OFF();
-
-//DbpString(parameter);
-
-	BYTE *receivedAnswer0 = (((BYTE *)BigBuf) + 3560); // allow 100 bytes per reponse (way too much)
-	BYTE *receivedAnswer1 = (((BYTE *)BigBuf) + 3660); //
-	BYTE *receivedAnswer2 = (((BYTE *)BigBuf) + 3760);
-	BYTE *receivedAnswer3 = (((BYTE *)BigBuf) + 3860);
-	//BYTE *TagUID= (((BYTE *)BigBuf) + 3960);		// where we hold the uid for hi15reader
-//	int responseLen0 = 0;
-	int responseLen1 = 0;
-//	int responseLen2 = 0;
-//	int responseLen3 = 0;
-
-	// Blank arrays
-	int j;
-	for(j = 0; j < 100; j++) {
-		receivedAnswer3[j] = 0;
-		receivedAnswer2[j] =0;
-		receivedAnswer1[j] = 0;
-		receivedAnswer0[j] = 0;
-	}
-
-	// Setup SSC
-	FpgaSetupSsc();
-
-	// Start from off (no field generated)
-    	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-    	SpinDelay(200);
-
-	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
-	FpgaSetupSsc();
-
-	// Give the tags time to energize
-//	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);	// NO GOOD FOR SIM TAG!!!!
-	SpinDelay(200);
-
-	LED_A_OFF();
-	LED_B_OFF();
-	LED_C_ON();
-	LED_D_OFF();
-
-	int samples = 0;
-	int tsamples = 0;
-	int wait = 0;
-	int elapsed = 0;
-
-	// FIRST WE RUN AN INVENTORY TO GET THE TAG UID
-	// THIS MEANS WE CAN PRE-BUILD REQUESTS TO SAVE CPU TIME
-	// BYTE TagUID[7];		// where we hold the uid for hi15reader
-
-	// Now send the IDENTIFY command
-	//	BuildIdentifyRequest();
-	//	TransmitTo15693Tag(ToSend,ToSendMax,&tsamples, &wait);	// No longer ToSendMax+3
-
-	// Now wait for a command from the reader
-	responseLen1=0;
-	//	while(responseLen1=0) {
-	//		if(BUTTON_PRESS()) break;
-		responseLen1 = GetIso15693AnswerFromSniff(receivedAnswer1, 100, &samples, &elapsed) ;
-	//		}
-
-	if (responseLen1 >=1) // we should do a better check than this
-	{
-		// Build a suitable reponse to the reader INVENTORY cocmmand
-		BuildInventoryResponse();
-		TransmitTo15693Reader(ToSend,ToSendMax,&tsamples, &wait);
-
-		// Now wait for a command from the reader
-//		responseLen2 = GetIso15693AnswerFromTag(receivedAnswer2, 100, &samples, &elapsed);
-
-		// Now wait for a command from the reader
-//		responseLen3 = GetIso15693AnswerFromTag(receivedAnswer3, 100, &samples, &elapsed) ;
-
-	}
-
-	char str1 [4];
-	//char str2 [200];
-	int i;
-
-	itoa(responseLen1,str1);
-	strcat(str1," octets read from reader command");
-	DbpString(str1);
-	for(i = 0; i < responseLen1; i+=3) {
-		DbpIntegers(receivedAnswer1[i],receivedAnswer1[i+1],receivedAnswer1[i+2]);
-	}
-
-//	itoa(responseLen2,str1);
-//	strcat(str1," octets read from SELECT request");
-//	DbpString(str1);
-//	for(i = 0; i < responseLen2; i+=3) {
-//		DbpIntegers(receivedAnswer2[i],receivedAnswer2[i+1],receivedAnswer2[i+2]);
-//	}
-//
-//	itoa(responseLen3,str1);
-//	strcat(str1," octets read from XXX request");
-//	DbpString(str1);
-//	for(i = 0; i < responseLen3; i+=3) {
-//		DbpIntegers(receivedAnswer3[i],receivedAnswer3[i+1],receivedAnswer3[i+2]);
-//	}
-
-//	str2[0]=0;
-//	for(i = 0; i < responseLen3; i++) {
-//		itoa(str1,receivedAnswer3[i]);
-//		strcat(str2,str1);
-//	}
-//	DbpString(str2);
-
-	LED_A_OFF();
-	LED_B_OFF();
-	LED_C_OFF();
-	LED_D_OFF();
-}
+//-----------------------------------------------------------------------------
+// Jonathan Westhues, split Nov 2006
+// Modified by Greg Jones, Jan 2009
+// Modified by Adrian Dabrowski "atrox", Mar-Sept 2010,Oct 2011
+// Modified by piwi, Oct 2018 
+//
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Routines to support ISO 15693. This includes both the reader software and
+// the `fake tag' modes.
+//-----------------------------------------------------------------------------
+
+// The ISO 15693 describes two transmission modes from reader to tag, and four
+// transmission modes from tag to reader. As of Oct 2018 this code supports
+// both reader modes and the high speed variant with one subcarrier from card to reader.
+// As long as the card fully support ISO 15693 this is no problem, since the
+// reader chooses both data rates, but some non-standard tags do not. 
+// For card simulation, the code supports both high and low speed modes with one subcarrier.
+//
+// VCD (reader) -> VICC (tag)
+// 1 out of 256:
+// 	data rate: 1,66 kbit/s (fc/8192)
+// 	used for long range
+// 1 out of 4:
+// 	data rate: 26,48 kbit/s (fc/512)
+//	used for short range, high speed
+//
+// VICC (tag) -> VCD (reader)
+// Modulation:
+//		ASK / one subcarrier (423,75 khz)
+//		FSK / two subcarriers (423,75 khz && 484,28 khz)
+// Data Rates / Modes:
+// 	low ASK: 6,62 kbit/s
+// 	low FSK: 6.67 kbit/s
+// 	high ASK: 26,48 kbit/s
+// 	high FSK: 26,69 kbit/s
+//-----------------------------------------------------------------------------
+
+
+// Random Remarks:
+// *) UID is always used "transmission order" (LSB), which is reverse to display order
+
+// TODO / BUGS / ISSUES:
+// *) signal decoding is unable to detect collisions.
+// *) add anti-collision support for inventory-commands
+// *) read security status of a block
+// *) sniffing and simulation do not support two subcarrier modes.
+// *) remove or refactor code under "deprecated"
+// *) document all the functions
+
+#include "iso15693.h"
+
+#include "proxmark3.h"
+#include "util.h"
+#include "apps.h"
+#include "string.h"
+#include "iso15693tools.h"
+#include "protocols.h"
+#include "cmd.h"
+#include "BigBuf.h"
+
+#define arraylen(x) (sizeof(x)/sizeof((x)[0]))
+
+static int DEBUG = 0;
+
+///////////////////////////////////////////////////////////////////////
+// ISO 15693 Part 2 - Air Interface
+// This section basicly contains transmission and receiving of bits
+///////////////////////////////////////////////////////////////////////
+
+#define Crc(data,datalen)     Iso15693Crc(data,datalen)
+#define AddCrc(data,datalen)  Iso15693AddCrc(data,datalen)
+#define sprintUID(target,uid)	Iso15693sprintUID(target,uid)
+
+// buffers
+#define ISO15693_DMA_BUFFER_SIZE        2048 // must be a power of 2
+#define ISO15693_MAX_RESPONSE_LENGTH     36 // allows read single block with the maximum block size of 256bits. Read multiple blocks not supported yet
+#define ISO15693_MAX_COMMAND_LENGTH      45 // allows write single block with the maximum block size of 256bits. Write multiple blocks not supported yet
+
+// timing. Delays in SSP_CLK ticks.
+#define DELAY_READER_TO_ARM            8
+#define DELAY_ARM_TO_READER            1
+#define DELAY_ISO15693_VCD_TO_VICC   132 // 132/423.75kHz = 311.5us from end of EOF to start of tag response
+#define DELAY_ISO15693_VICC_TO_VCD  1017 // 1017/3.39MHz = 300us between end of tag response and next reader command
+
+// ---------------------------
+// Signal Processing
+// ---------------------------
+
+// prepare data using "1 out of 4" code for later transmission
+// 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;
+
+	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;
+			switch(these) {
+				case 0:
+					ToSendStuffBit(1);
+					ToSendStuffBit(0);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					break;
+				case 1:
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(0);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					break;
+				case 2:
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(0);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					break;
+				case 3:
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(1);
+					ToSendStuffBit(0);
+					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);
+	}
+	
+	ToSendMax++;
+}
+
+// encode data using "1 out of 256" scheme
+// data rate is 1,66 kbit/s (fc/8192)
+// 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);
+				ToSendStuffBit(0);
+			} else {
+				ToSendStuffBit(1);
+				ToSendStuffBit(1);
+			}
+		}
+	}
+	// EOF
+	ToSendStuffBit(1);
+	ToSendStuffBit(1);
+	ToSendStuffBit(0);
+	ToSendStuffBit(1);
+
+	// Fill remainder of last byte with 1
+	for(i = 0; i < 4; i++) {
+		ToSendStuffBit(1);
+	}
+
+	ToSendMax++;
+}
+
+
+static void CodeIso15693AsTag(uint8_t *cmd, int n)
+{
+	ToSendReset();
+
+	// SOF
+	ToSendStuffBit(0);
+	ToSendStuffBit(0);
+	ToSendStuffBit(0);
+	ToSendStuffBit(1);
+	ToSendStuffBit(1);
+	ToSendStuffBit(1);
+	ToSendStuffBit(0);
+	ToSendStuffBit(1);
+
+	// data
+	for(int i = 0; i < n; i++) {
+		for(int j = 0; j < 8; j++) {
+			if ((cmd[i] >> j) & 0x01) {
+					ToSendStuffBit(0);
+					ToSendStuffBit(1);
+			} else {
+					ToSendStuffBit(1);
+					ToSendStuffBit(0);
+			}
+		}
+	}
+
+	// EOF
+	ToSendStuffBit(1);
+	ToSendStuffBit(0);
+	ToSendStuffBit(1);
+	ToSendStuffBit(1);
+	ToSendStuffBit(1);
+	ToSendStuffBit(0);
+	ToSendStuffBit(0);
+	ToSendStuffBit(0);
+
+	ToSendMax++;
+}
+
+
+// Transmit the command (to the tag) that was placed in cmd[].
+static void TransmitTo15693Tag(const uint8_t *cmd, int len, uint32_t start_time)
+{
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
+
+	while (GetCountSspClk() < start_time);
+
+	LED_B_ON();
+    for(int c = 0; c < len; ) {
+        if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+            AT91C_BASE_SSC->SSC_THR = ~cmd[c];
+            c++;
+        }
+        WDT_HIT();
+    }
+	LED_B_OFF();
+}
+
+//-----------------------------------------------------------------------------
+// Transmit the tag response (to the reader) that was placed in cmd[].
+//-----------------------------------------------------------------------------
+static void TransmitTo15693Reader(const uint8_t *cmd, size_t len, uint32_t start_time, bool slow)
+{
+	// 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);
+
+	uint8_t shift_delay = start_time & 0x00000007;
+	uint8_t bitmask = 0x00;
+	for (int i = 0; i < shift_delay; i++) {
+		bitmask |= (0x01 << i);
+	}
+
+	while (GetCountSspClk() < (start_time & 0xfffffff8)) ;
+
+	AT91C_BASE_SSC->SSC_THR = 0x00; // clear TXRDY
+
+	LED_C_ON();
+	uint8_t bits_to_shift = 0x00;
+    for(size_t c = 0; c <= len; c++) {
+		uint8_t bits_to_send = bits_to_shift << (8 - shift_delay) | (c==len?0x00:cmd[c]) >> shift_delay;
+		bits_to_shift = cmd[c] & bitmask;
+		for (int i = 7; i >= 0; i--) {
+			for (int j = 0; j < (slow?4:1); ) {
+				if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+					if (bits_to_send >> i & 0x01) {
+						AT91C_BASE_SSC->SSC_THR = 0xff;
+					} else {
+						AT91C_BASE_SSC->SSC_THR = 0x00;
+					}
+					j++;
+				}
+				WDT_HIT();
+			}
+        }
+    }
+	LED_C_OFF();
+}
+
+
+//=============================================================================
+// An ISO 15693 decoder for tag responses (one subcarrier only).
+// Uses cross correlation to identify each bit and EOF.
+// This function is called 8 times per bit (every 2 subcarrier cycles).
+// Subcarrier frequency fs is 424kHz, 1/fs = 2,36us,
+// i.e. function is called every 4,72us
+// LED handling:
+//    LED C -> ON once we have received the SOF and are expecting the rest.
+//    LED C -> OFF once we have received EOF or are unsynced
+//
+// Returns: true if we received a EOF
+//          false if we are still waiting for some more
+//=============================================================================
+
+#define NOISE_THRESHOLD    160      // don't try to correlate noise
+
+typedef struct DecodeTag {
+	enum {
+		STATE_TAG_SOF_LOW,
+		STATE_TAG_SOF_HIGH,
+		STATE_TAG_SOF_HIGH_END,
+		STATE_TAG_RECEIVING_DATA,
+		STATE_TAG_EOF
+	}         state;
+	int       bitCount;
+	int       posCount;
+	enum {
+		LOGIC0,
+		LOGIC1,
+		SOF_PART1,
+		SOF_PART2
+	}         lastBit;
+	uint16_t  shiftReg;
+	uint16_t  max_len;
+	uint8_t   *output;
+	int       len;
+	int       sum1, sum2;
+} DecodeTag_t;
+
+
+static int inline __attribute__((always_inline)) Handle15693SamplesFromTag(uint16_t amplitude, DecodeTag_t *DecodeTag)
+{
+	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 {
+				if (DecodeTag->posCount > 10) {
+					DecodeTag->posCount = 1;
+					DecodeTag->sum1 = 0;
+					DecodeTag->state = STATE_TAG_SOF_HIGH;
+				} else {
+					DecodeTag->posCount = 0;
+				}
+			}
+			break;
+			
+		case STATE_TAG_SOF_HIGH:
+			// waiting for 10 times high. Take average over the last 8
+			if (amplitude > NOISE_THRESHOLD) {
+				DecodeTag->posCount++;
+				if (DecodeTag->posCount > 2) {
+					DecodeTag->sum1 += amplitude; // keep track of average high value
+				}
+				if (DecodeTag->posCount == 10) {
+					DecodeTag->sum1 >>= 4;        // calculate half of average high value (8 samples)
+					DecodeTag->state = STATE_TAG_SOF_HIGH_END;
+				}
+			} else { // high phase was too short
+				DecodeTag->posCount = 1;
+				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
+				DecodeTag->lastBit = SOF_PART1;  // detected 1st part of SOF (12 samples low and 12 samples high)
+				DecodeTag->shiftReg = 0;
+				DecodeTag->bitCount = 0;
+				DecodeTag->len = 0;
+				DecodeTag->sum1 = amplitude;
+				DecodeTag->sum2 = 0;
+				DecodeTag->posCount = 2;
+				DecodeTag->state = STATE_TAG_RECEIVING_DATA;
+				LED_C_ON();
+			} else {
+				DecodeTag->posCount++;
+				if (DecodeTag->posCount > 13) { // high phase too long
+					DecodeTag->posCount = 0;
+					DecodeTag->state = STATE_TAG_SOF_LOW;
+					LED_C_OFF();
+				}
+			}
+			break;
+
+		case STATE_TAG_RECEIVING_DATA:
+			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) {
+				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->lastBit == LOGIC0) {  // this was already part of EOF
+						DecodeTag->state = STATE_TAG_EOF;
+					} else {
+						DecodeTag->posCount = 0;
+						DecodeTag->state = STATE_TAG_SOF_LOW;
+						LED_C_OFF();
+					}
+				} else if (corr_1 > corr_0) {
+					// logic 1
+					if (DecodeTag->lastBit == SOF_PART1) { // still part of SOF
+						DecodeTag->lastBit = SOF_PART2;    // SOF completed
+					} else {
+						DecodeTag->lastBit = LOGIC1;
+						DecodeTag->shiftReg >>= 1;
+						DecodeTag->shiftReg |= 0x80;
+						DecodeTag->bitCount++;
+						if (DecodeTag->bitCount == 8) {
+							DecodeTag->output[DecodeTag->len] = DecodeTag->shiftReg;
+							DecodeTag->len++;
+							if (DecodeTag->len > DecodeTag->max_len) {
+								// buffer overflow, give up
+								DecodeTag->posCount = 0;
+								DecodeTag->state = STATE_TAG_SOF_LOW;
+								LED_C_OFF();
+							}
+							DecodeTag->bitCount = 0;
+							DecodeTag->shiftReg = 0;
+						}
+					}
+				} else {
+					// logic 0
+					if (DecodeTag->lastBit == SOF_PART1) { // incomplete SOF
+						DecodeTag->posCount = 0;
+						DecodeTag->state = STATE_TAG_SOF_LOW;
+						LED_C_OFF();
+					} else {
+						DecodeTag->lastBit = LOGIC0;
+						DecodeTag->shiftReg >>= 1;
+						DecodeTag->bitCount++;
+						if (DecodeTag->bitCount == 8) {
+							DecodeTag->output[DecodeTag->len] = DecodeTag->shiftReg;
+							DecodeTag->len++;
+							if (DecodeTag->len > DecodeTag->max_len) {
+								// buffer overflow, give up
+								DecodeTag->posCount = 0;
+								DecodeTag->state = STATE_TAG_SOF_LOW;
+								LED_C_OFF();
+							}
+							DecodeTag->bitCount = 0;
+							DecodeTag->shiftReg = 0;
+						}
+					}
+				}
+				DecodeTag->posCount = 0;
+			}
+			DecodeTag->posCount++;
+			break;
+
+		case STATE_TAG_EOF:
+			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) {
+				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) {
+					DecodeTag->posCount = 0;
+					DecodeTag->state = STATE_TAG_SOF_LOW;
+					LED_C_OFF();
+				} else {
+					LED_C_OFF();
+					return true;
+				}
+			}
+			DecodeTag->posCount++;
+			break;
+
+	}
+
+	return false;
+}
+
+
+static void DecodeTagInit(DecodeTag_t *DecodeTag, uint8_t *data, uint16_t max_len)
+{
+	DecodeTag->posCount = 0;
+	DecodeTag->state = STATE_TAG_SOF_LOW;
+	DecodeTag->output = data;
+	DecodeTag->max_len = max_len;
+}
+
+
+static void DecodeTagReset(DecodeTag_t *DecodeTag)
+{
+	DecodeTag->posCount = 0;
+	DecodeTag->state = STATE_TAG_SOF_LOW;
+}
+
+
+/*
+ *  Receive and decode the tag response, also log to tracebuffer
+ */
+static int GetIso15693AnswerFromTag(uint8_t* response, uint16_t max_len, int timeout)
+{
+	int samples = 0;
+	bool gotFrame = false;
+
+	uint16_t *dmaBuf = (uint16_t*)BigBuf_malloc(ISO15693_DMA_BUFFER_SIZE*sizeof(uint16_t));
+	
+	// the Decoder data structure
+	DecodeTag_t DecodeTag = { 0 };
+	DecodeTagInit(&DecodeTag, response, max_len);
+
+	// wait for last transfer to complete
+	while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY));
+
+	// And put the FPGA in the appropriate mode
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_AMPLITUDE);
+
+	// Setup and start DMA.
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+	uint16_t *upTo = dmaBuf;
+
+	for(;;) {
+		uint16_t behindBy = ((uint16_t*)AT91C_BASE_PDC_SSC->PDC_RPR - upTo) & (ISO15693_DMA_BUFFER_SIZE-1);
+
+		if (behindBy == 0) continue;
+
+		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);
+				break;
+			}
+		}
+		if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
+			AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
+			AT91C_BASE_PDC_SSC->PDC_RNCR = ISO15693_DMA_BUFFER_SIZE;   // DMA Next Counter registers
+		}
+
+		samples++;
+
+		if (Handle15693SamplesFromTag(tagdata, &DecodeTag)) {
+			gotFrame = true;
+			break;
+		}
+
+		if (samples > timeout && DecodeTag.state < STATE_TAG_RECEIVING_DATA) {
+			DecodeTag.len = 0;
+			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 (DecodeTag.len > 0) {
+		LogTrace(DecodeTag.output, DecodeTag.len, 0, 0, NULL, false);
+	}
+
+	return DecodeTag.len;
+}
+
+
+//=============================================================================
+// An ISO15693 decoder for reader commands.
+//
+// This function is called 4 times per bit (every 2 subcarrier cycles).
+// Subcarrier frequency fs is 848kHz, 1/fs = 1,18us, i.e. function is called every 2,36us
+// LED handling:
+//    LED B -> ON once we have received the SOF and are expecting the rest.
+//    LED B -> OFF once we have received EOF or are in error state or unsynced
+//
+// Returns: true  if we received a EOF
+//          false if we are still waiting for some more
+//=============================================================================
+
+typedef struct DecodeReader {
+	enum {
+		STATE_READER_UNSYNCD,
+		STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF,
+		STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF,
+		STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF,
+		STATE_READER_AWAIT_END_OF_SOF_1_OUT_OF_4,
+		STATE_READER_RECEIVE_DATA_1_OUT_OF_4,
+		STATE_READER_RECEIVE_DATA_1_OUT_OF_256
+	}           state;
+	enum {
+		CODING_1_OUT_OF_4,
+		CODING_1_OUT_OF_256
+	}           Coding;
+	uint8_t     shiftReg;
+	uint8_t     bitCount;
+	int         byteCount;
+	int         byteCountMax;
+	int         posCount;
+	int			sum1, sum2;
+	uint8_t     *output;
+} DecodeReader_t;
+
+
+static void DecodeReaderInit(DecodeReader_t* DecodeReader, uint8_t *data, uint16_t max_len)
+{
+	DecodeReader->output = data;
+	DecodeReader->byteCountMax = max_len;
+	DecodeReader->state = STATE_READER_UNSYNCD;
+	DecodeReader->byteCount = 0;
+	DecodeReader->bitCount = 0;
+	DecodeReader->posCount = 1;
+	DecodeReader->shiftReg = 0;
+}
+
+
+static void DecodeReaderReset(DecodeReader_t* DecodeReader)
+{
+	DecodeReader->state = STATE_READER_UNSYNCD;
+}
+
+
+static int inline __attribute__((always_inline)) Handle15693SampleFromReader(uint8_t bit, DecodeReader_t *restrict DecodeReader)
+{
+	switch(DecodeReader->state) {
+		case STATE_READER_UNSYNCD:
+			if(!bit) {
+				// we went low, so this could be the beginning of a SOF
+				DecodeReader->posCount = 1;
+				DecodeReader->state = STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF;
+			}
+			break;
+
+		case STATE_READER_AWAIT_1ST_RISING_EDGE_OF_SOF:
+			DecodeReader->posCount++;
+			if(bit) { // detected rising edge
+				if(DecodeReader->posCount < 4) { // rising edge too early (nominally expected at 5)
+					DecodeReaderReset(DecodeReader);
+				} else { // SOF
+					DecodeReader->state = STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF;
+				}
+			} else {
+				if(DecodeReader->posCount > 5) { // stayed low for too long
+					DecodeReaderReset(DecodeReader);
+				} else {
+					// do nothing, keep waiting
+				}
+			}
+			break;
+
+		case STATE_READER_AWAIT_2ND_FALLING_EDGE_OF_SOF:
+			DecodeReader->posCount++;
+			if(!bit) { // detected a falling edge
+				if (DecodeReader->posCount < 20) {         // falling edge too early (nominally expected at 21 earliest)
+					DecodeReaderReset(DecodeReader);
+				} else if (DecodeReader->posCount < 23) {  // SOF for 1 out of 4 coding
+					DecodeReader->Coding = CODING_1_OUT_OF_4;
+					DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
+				} else if (DecodeReader->posCount < 28) {  // falling edge too early (nominally expected at 29 latest)
+					DecodeReaderReset(DecodeReader);
+				} else {                                 // SOF for 1 out of 4 coding
+					DecodeReader->Coding = CODING_1_OUT_OF_256;
+					DecodeReader->state = STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF;
+				}
+			} else {
+				if(DecodeReader->posCount > 29) { // stayed high for too long
+					DecodeReaderReset(DecodeReader);
+				} else {
+					// do nothing, keep waiting
+				}
+			}
+			break;
+
+		case STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF:
+			DecodeReader->posCount++;
+			if (bit) { // detected rising edge
+				if (DecodeReader->Coding == CODING_1_OUT_OF_256) {
+					if (DecodeReader->posCount < 32) { // rising edge too early (nominally expected at 33)
+					DecodeReaderReset(DecodeReader);
+					} else {
+						DecodeReader->posCount = 1;
+						DecodeReader->bitCount = 0;
+						DecodeReader->byteCount = 0;
+						DecodeReader->sum1 = 1;
+						DecodeReader->state = STATE_READER_RECEIVE_DATA_1_OUT_OF_256;
+						LED_B_ON();
+					}
+				} else { // CODING_1_OUT_OF_4
+					if (DecodeReader->posCount < 24) { // rising edge too early (nominally expected at 25)
+					DecodeReaderReset(DecodeReader);
+					} else {
+						DecodeReader->state = STATE_READER_AWAIT_END_OF_SOF_1_OUT_OF_4;
+					}
+				}
+			} else {
+				if (DecodeReader->Coding == CODING_1_OUT_OF_256) {
+					if (DecodeReader->posCount > 34) { // signal stayed low for too long
+					DecodeReaderReset(DecodeReader);
+					} else {
+						// do nothing, keep waiting
+					}
+				} else { // CODING_1_OUT_OF_4
+					if (DecodeReader->posCount > 26) { // signal stayed low for too long
+					DecodeReaderReset(DecodeReader);
+					} else {
+						// do nothing, keep waiting
+					}
+				}
+			}
+			break;
+
+		case STATE_READER_AWAIT_END_OF_SOF_1_OUT_OF_4:
+			DecodeReader->posCount++;
+			if (bit) {
+				if (DecodeReader->posCount == 33) {
+					DecodeReader->posCount = 1;
+					DecodeReader->bitCount = 0;
+					DecodeReader->byteCount = 0;
+					DecodeReader->sum1 = 1;
+					DecodeReader->state = STATE_READER_RECEIVE_DATA_1_OUT_OF_4;
+					LED_B_ON();
+				} else {
+					// do nothing, keep waiting
+				}
+			} else { // unexpected falling edge
+					DecodeReaderReset(DecodeReader);
+			}
+			break;
+
+		case STATE_READER_RECEIVE_DATA_1_OUT_OF_4:
+			DecodeReader->posCount++;
+			if (DecodeReader->posCount == 1) {
+				DecodeReader->sum1 = bit;
+			} else if (DecodeReader->posCount <= 4) {
+				DecodeReader->sum1 += bit;
+			} else if (DecodeReader->posCount == 5) {
+				DecodeReader->sum2 = bit;
+			} else {
+				DecodeReader->sum2 += bit;
+			}
+			if (DecodeReader->posCount == 8) {
+				DecodeReader->posCount = 0;
+				int corr10 = DecodeReader->sum1 - DecodeReader->sum2;
+				int corr01 = DecodeReader->sum2 - DecodeReader->sum1;
+				int corr11 = (DecodeReader->sum1 + DecodeReader->sum2) / 2;
+				if (corr01 > corr11 && corr01 > corr10) { // EOF
+					LED_B_OFF(); // Finished receiving
+					DecodeReaderReset(DecodeReader);
+					if (DecodeReader->byteCount != 0) {
+						return true;
+					}
+				}
+				if (corr10 > corr11) { // detected a 2bit position
+					DecodeReader->shiftReg >>= 2;
+					DecodeReader->shiftReg |= (DecodeReader->bitCount << 6);
+				}
+				if (DecodeReader->bitCount == 15) { // we have a full byte
+					DecodeReader->output[DecodeReader->byteCount++] = DecodeReader->shiftReg;
+					if (DecodeReader->byteCount > DecodeReader->byteCountMax) {
+						// buffer overflow, give up
+						LED_B_OFF();
+						DecodeReaderReset(DecodeReader);
+					}
+					DecodeReader->bitCount = 0;
+					DecodeReader->shiftReg = 0;
+				} else {
+					DecodeReader->bitCount++;
+				}
+			}
+			break;
+
+		case STATE_READER_RECEIVE_DATA_1_OUT_OF_256:
+			DecodeReader->posCount++;
+			if (DecodeReader->posCount == 1) {
+				DecodeReader->sum1 = bit;
+			} else if (DecodeReader->posCount <= 4) {
+				DecodeReader->sum1 += bit;
+			} else if (DecodeReader->posCount == 5) {
+				DecodeReader->sum2 = bit;
+			} else {
+				DecodeReader->sum2 += bit;
+			}
+			if (DecodeReader->posCount == 8) {
+				DecodeReader->posCount = 0;
+				int corr10 = DecodeReader->sum1 - DecodeReader->sum2;
+				int corr01 = DecodeReader->sum2 - DecodeReader->sum1;
+				int corr11 = (DecodeReader->sum1 + DecodeReader->sum2) / 2;
+				if (corr01 > corr11 && corr01 > corr10) { // EOF
+					LED_B_OFF(); // Finished receiving
+					DecodeReaderReset(DecodeReader);
+					if (DecodeReader->byteCount != 0) {
+						return true;
+					}
+				}
+				if (corr10 > corr11) { // detected the bit position
+					DecodeReader->shiftReg = DecodeReader->bitCount;
+				}
+				if (DecodeReader->bitCount == 255) { // we have a full byte
+					DecodeReader->output[DecodeReader->byteCount++] = DecodeReader->shiftReg;
+					if (DecodeReader->byteCount > DecodeReader->byteCountMax) {
+						// buffer overflow, give up
+						LED_B_OFF();
+						DecodeReaderReset(DecodeReader);
+					}
+				}
+				DecodeReader->bitCount++;
+			}
+			break;
+
+		default:
+			LED_B_OFF();
+			DecodeReaderReset(DecodeReader);
+			break;
+	}
+
+	return false;
+}
+
+
+//-----------------------------------------------------------------------------
+// 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
+// spinning, waiting for a well-framed command, until either we get one
+// (returns true) or someone presses the pushbutton on the board (false).
+//
+// Assume that we're called with the SSC (to the FPGA) and ADC path set
+// correctly.
+//-----------------------------------------------------------------------------
+
+static int GetIso15693CommandFromReader(uint8_t *received, size_t max_len, uint32_t *eof_time)
+{
+	int samples = 0;
+	bool gotFrame = false;
+	uint8_t b;
+
+	uint8_t *dmaBuf = BigBuf_malloc(ISO15693_DMA_BUFFER_SIZE);
+
+	// the decoder data structure
+	DecodeReader_t DecodeReader = {0};
+	DecodeReaderInit(&DecodeReader, received, max_len);
+
+	// wait for last transfer to complete
+	while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY));
+
+	LED_D_OFF();
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
+
+	// clear receive register and wait for next transfer
+	uint32_t temp = AT91C_BASE_SSC->SSC_RHR;
+	(void) temp;
+	while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY)) ;
+
+	uint32_t bit_time = GetCountSspClk() & 0xfffffff8;
+
+	// Setup and start DMA.
+	FpgaSetupSscDma(dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+	uint8_t *upTo = dmaBuf;
+
+	for(;;) {
+		uint16_t behindBy = ((uint8_t*)AT91C_BASE_PDC_SSC->PDC_RPR - upTo) & (ISO15693_DMA_BUFFER_SIZE-1);
+
+		if (behindBy == 0) continue;
+
+		b = *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);
+				break;
+			}
+		}
+		if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
+			AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
+			AT91C_BASE_PDC_SSC->PDC_RNCR = ISO15693_DMA_BUFFER_SIZE;   // DMA Next Counter registers
+		}
+
+		for (int i = 7; i >= 0; i--) {
+			if (Handle15693SampleFromReader((b >> i) & 0x01, &DecodeReader)) {
+				*eof_time = bit_time + samples - DELAY_READER_TO_ARM; // end of EOF
+				gotFrame = true;
+				break;
+			}
+			samples++;
+		}
+
+		if (gotFrame) {
+			break;
+		}
+
+		if (BUTTON_PRESS()) {
+			DecodeReader.byteCount = 0;
+			break;
+		}
+
+		WDT_HIT();
+	}
+
+
+	FpgaDisableSscDma();
+	BigBuf_free_keep_EM();
+	
+	if (DEBUG) Dbprintf("samples = %d, gotFrame = %d, Decoder: state = %d, len = %d, bitCount = %d, posCount = %d",
+	                    samples, gotFrame, DecodeReader.state, DecodeReader.byteCount, DecodeReader.bitCount, DecodeReader.posCount);
+
+	if (DecodeReader.byteCount > 0) {
+		LogTrace(DecodeReader.output, DecodeReader.byteCount, 0, 0, NULL, true);
+	}
+
+	return DecodeReader.byteCount;
+}
+
+
+// Encode (into the ToSend buffers) an identify request, which is the first
+// thing that you must send to a tag to get a response.
+static void BuildIdentifyRequest(void)
+{
+	uint8_t cmd[5];
+
+	uint16_t crc;
+	// one sub-carrier, inventory, 1 slot, fast rate
+	// AFI is at bit 5 (1<<4) when doing an INVENTORY
+	cmd[0] = (1 << 2) | (1 << 5) | (1 << 1);
+	// inventory command code
+	cmd[1] = 0x01;
+	// no mask
+	cmd[2] = 0x00;
+	//Now the CRC
+	crc = Crc(cmd, 3);
+	cmd[3] = crc & 0xff;
+	cmd[4] = crc >> 8;
+
+	CodeIso15693AsReader(cmd, sizeof(cmd));
+}
+
+
+//-----------------------------------------------------------------------------
+// Start to read an ISO 15693 tag. We send an identify request, then wait
+// for the response. The response is not demodulated, just left in the buffer
+// so that it can be downloaded to a PC and processed there.
+//-----------------------------------------------------------------------------
+void AcquireRawAdcSamplesIso15693(void)
+{
+	LEDsoff();
+	LED_A_ON();
+
+	uint8_t *dest = BigBuf_get_addr();
+
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	BuildIdentifyRequest();
+
+	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+
+	// Give the tags time to energize
+	LED_D_ON();
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	SpinDelay(100);
+
+	// Now send the command
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_TX);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_TX);
+
+	LED_B_ON();
+	for(int c = 0; c < ToSendMax; ) {
+		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+			AT91C_BASE_SSC->SSC_THR = ~ToSend[c];
+			c++;
+		}
+		WDT_HIT();
+	}
+	LED_B_OFF();
+
+	// wait for last transfer to complete
+	while (!(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXEMPTY));
+
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_AMPLITUDE);
+
+	for(int c = 0; c < 4000; ) {
+		if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+			uint16_t r = AT91C_BASE_SSC->SSC_RHR;
+			dest[c++] = r >> 5;
+		}
+	}
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	LEDsoff();
+}
+
+
+void SnoopIso15693(void)
+{
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	BigBuf_free();
+
+	clear_trace();
+	set_tracing(true);
+
+
+	// The DMA buffer, used to stream samples from the FPGA
+	uint16_t* dmaBuf = (uint16_t*)BigBuf_malloc(ISO15693_DMA_BUFFER_SIZE*sizeof(uint16_t));
+	uint16_t *upTo;
+
+	// Count of samples received so far, so that we can include timing
+	// information in the trace buffer.
+	int samples = 0;
+
+	DecodeTag_t DecodeTag = {0};
+	uint8_t response[ISO15693_MAX_RESPONSE_LENGTH];
+	DecodeTagInit(&DecodeTag, response, sizeof(response));
+
+	DecodeReader_t DecodeReader = {0};;
+	uint8_t cmd[ISO15693_MAX_COMMAND_LENGTH];
+	DecodeReaderInit(&DecodeReader, cmd, sizeof(cmd));
+
+	// Print some debug information about the buffer sizes
+	if (DEBUG) {
+		Dbprintf("Snooping buffers initialized:");
+		Dbprintf("  Trace:         %i bytes", BigBuf_max_traceLen());
+		Dbprintf("  Reader -> tag: %i bytes", ISO15693_MAX_COMMAND_LENGTH);
+		Dbprintf("  tag -> Reader: %i bytes", ISO15693_MAX_RESPONSE_LENGTH);
+		Dbprintf("  DMA:           %i bytes", ISO15693_DMA_BUFFER_SIZE * sizeof(uint16_t));
+	}
+	Dbprintf("Snoop started. Press button to stop.");
+	
+	// Signal field is off, no reader signal, no tag signal
+	LEDsoff();
+	// And put the FPGA in the appropriate mode
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR | FPGA_HF_READER_RX_XCORR_SNOOP | FPGA_HF_READER_RX_XCORR_AMPLITUDE);
+	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+
+	// Setup for the DMA.
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	upTo = dmaBuf;
+	FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+
+	bool TagIsActive = false;
+	bool ReaderIsActive = false;
+	bool ExpectTagAnswer = false;
+
+	// And now we loop, receiving samples.
+	for(;;) {
+		uint16_t behindBy = ((uint16_t*)AT91C_BASE_PDC_SSC->PDC_RPR - upTo) & (ISO15693_DMA_BUFFER_SIZE-1);
+
+		if (behindBy == 0) continue;
+
+		uint16_t snoopdata = *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, samples=%d", behindBy, samples);
+				break;
+			}
+			if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_ENDRX)) {              // DMA Counter Register had reached 0, already rotated.
+				AT91C_BASE_PDC_SSC->PDC_RNPR = (uint32_t) dmaBuf;          // refresh the DMA Next Buffer and
+				AT91C_BASE_PDC_SSC->PDC_RNCR = ISO15693_DMA_BUFFER_SIZE;   // DMA Next Counter registers
+				WDT_HIT();
+				if(BUTTON_PRESS()) {
+					DbpString("Snoop stopped.");
+					break;
+				}
+			}
+		}
+		samples++;
+		
+		if (!TagIsActive) {                                            // no need to try decoding reader data if the tag is sending
+			if (Handle15693SampleFromReader(snoopdata & 0x02, &DecodeReader)) {
+				FpgaDisableSscDma();
+				ExpectTagAnswer = true;
+				LogTrace(DecodeReader.output, DecodeReader.byteCount, samples, samples, NULL, true);
+				/* And ready to receive another command. */
+				DecodeReaderReset(&DecodeReader);
+				/* And also reset the demod code, which might have been */
+				/* false-triggered by the commands from the reader. */
+				DecodeTagReset(&DecodeTag);
+				upTo = dmaBuf;
+				FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+			}
+			if (Handle15693SampleFromReader(snoopdata & 0x01, &DecodeReader)) {
+				FpgaDisableSscDma();
+				ExpectTagAnswer = true;
+				LogTrace(DecodeReader.output, DecodeReader.byteCount, samples, samples, NULL, true);
+				/* And ready to receive another command. */
+				DecodeReaderReset(&DecodeReader);
+				/* And also reset the demod code, which might have been */
+				/* false-triggered by the commands from the reader. */
+				DecodeTagReset(&DecodeTag);
+				upTo = dmaBuf;
+				FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+			}
+			ReaderIsActive = (DecodeReader.state >= STATE_READER_AWAIT_2ND_RISING_EDGE_OF_SOF);
+		}
+
+		if (!ReaderIsActive && ExpectTagAnswer) {						// no need to try decoding tag data if the reader is currently sending or no answer expected yet
+			if (Handle15693SamplesFromTag(snoopdata >> 2, &DecodeTag)) {
+				FpgaDisableSscDma();
+				//Use samples as a time measurement
+				LogTrace(DecodeTag.output, DecodeTag.len, samples, samples, NULL, false);
+				// And ready to receive another response.
+				DecodeTagReset(&DecodeTag);
+				DecodeReaderReset(&DecodeReader);
+				ExpectTagAnswer = false;
+				upTo = dmaBuf;
+				FpgaSetupSscDma((uint8_t*) dmaBuf, ISO15693_DMA_BUFFER_SIZE);
+			}
+			TagIsActive = (DecodeTag.state >= STATE_TAG_RECEIVING_DATA);
+		}
+
+	}
+
+	FpgaDisableSscDma();
+	BigBuf_free();
+	
+	LEDsoff();
+
+	DbpString("Snoop statistics:");
+	Dbprintf("  ExpectTagAnswer: %d", ExpectTagAnswer);
+	Dbprintf("  DecodeTag State: %d", DecodeTag.state);
+	Dbprintf("  DecodeTag byteCnt: %d", DecodeTag.len);
+	Dbprintf("  DecodeReader State: %d", DecodeReader.state);
+	Dbprintf("  DecodeReader byteCnt: %d", DecodeReader.byteCount);
+	Dbprintf("  Trace length: %d", BigBuf_get_traceLen());
+}
+
+
+// Initialize the proxmark as iso15k reader
+// (this might produces glitches that confuse some tags
+static void Iso15693InitReader() {
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	// Setup SSC
+	// FpgaSetupSsc();
+
+	// Start from off (no field generated)
+	LED_D_OFF();
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	SpinDelay(10);
+
+	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+
+	// Give the tags time to energize
+	LED_D_ON();
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	SpinDelay(250);
+}
+
+///////////////////////////////////////////////////////////////////////
+// ISO 15693 Part 3 - Air Interface
+// This section basically contains transmission and receiving of bits
+///////////////////////////////////////////////////////////////////////
+
+
+// uid is in transmission order (which is reverse of display order)
+static void BuildReadBlockRequest(uint8_t *uid, uint8_t blockNumber )
+{
+	uint8_t cmd[13];
+
+	uint16_t crc;
+	// If we set the Option_Flag in this request, the VICC will respond with the security status of the block
+	// followed by the block data
+	cmd[0] = ISO15693_REQ_OPTION | ISO15693_REQ_ADDRESS | ISO15693_REQ_DATARATE_HIGH; 
+	// READ BLOCK command code
+	cmd[1] = ISO15693_READBLOCK;
+	// UID may be optionally specified here
+	// 64-bit UID
+	cmd[2] = uid[0];
+	cmd[3] = uid[1];
+	cmd[4] = uid[2];
+	cmd[5] = uid[3];
+	cmd[6] = uid[4];
+	cmd[7] = uid[5];
+	cmd[8] = uid[6];
+	cmd[9] = uid[7]; // 0xe0; // always e0 (not exactly unique)
+	// Block number to read
+	cmd[10] = blockNumber;
+	//Now the CRC
+	crc = Crc(cmd, 11); // the crc needs to be calculated over 11 bytes
+	cmd[11] = crc & 0xff;
+	cmd[12] = crc >> 8;
+
+	CodeIso15693AsReader(cmd, sizeof(cmd));
+}
+
+
+// Now the VICC>VCD responses when we are simulating a tag
+static void BuildInventoryResponse(uint8_t *uid)
+{
+	uint8_t cmd[12];
+
+	uint16_t crc;
+
+	cmd[0] = 0; // No error, no protocol format extension
+	cmd[1] = 0; // DSFID (data storage format identifier).  0x00 = not supported
+	// 64-bit UID
+	cmd[2] = uid[7]; //0x32;
+	cmd[3] = uid[6]; //0x4b;
+	cmd[4] = uid[5]; //0x03;
+	cmd[5] = uid[4]; //0x01;
+	cmd[6] = uid[3]; //0x00;
+	cmd[7] = uid[2]; //0x10;
+	cmd[8] = uid[1]; //0x05;
+	cmd[9] = uid[0]; //0xe0;
+	//Now the CRC
+	crc = Crc(cmd, 10);
+	cmd[10] = crc & 0xff;
+	cmd[11] = crc >> 8;
+
+	CodeIso15693AsTag(cmd, sizeof(cmd));
+}
+
+// Universal Method for sending to and recv bytes from a tag
+// 	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) {
+
+	LED_A_ON();
+	LED_B_OFF();
+	LED_C_OFF();
+
+	if (init) Iso15693InitReader();
+
+	int answerLen=0;
+
+	if (!speed) {
+		// low speed (1 out of 256)
+		CodeIso15693AsReader256(send, sendlen);
+	} else {
+		// high speed (1 out of 4)
+		CodeIso15693AsReader(send, sendlen);
+	}
+
+	TransmitTo15693Tag(ToSend, ToSendMax, start_time);
+
+	// Now wait for a response
+	if (recv != NULL) {
+		answerLen = GetIso15693AnswerFromTag(recv, max_recv_len, DELAY_ISO15693_VCD_TO_VICC * 2);
+	}
+
+	LED_A_OFF();
+
+	return answerLen;
+}
+
+
+// --------------------------------------------------------------------
+// Debug Functions
+// --------------------------------------------------------------------
+
+// Decodes a message from a tag and displays its metadata and content
+#define DBD15STATLEN 48
+void DbdecodeIso15693Answer(int len, uint8_t *d) {
+	char status[DBD15STATLEN+1]={0};
+	uint16_t crc;
+
+	if (len > 3) {
+		if (d[0] & ISO15693_RES_EXT)
+			strncat(status,"ProtExt ", DBD15STATLEN);
+		if (d[0] & ISO15693_RES_ERROR) {
+			// error
+			strncat(status,"Error ", DBD15STATLEN);
+			switch (d[1]) {
+				case 0x01:
+					strncat(status,"01:notSupp", DBD15STATLEN);
+					break;
+				case 0x02:
+					strncat(status,"02:notRecog", DBD15STATLEN);
+					break;
+				case 0x03:
+					strncat(status,"03:optNotSupp", DBD15STATLEN);
+					break;
+				case 0x0f:
+					strncat(status,"0f:noInfo", DBD15STATLEN);
+					break;
+				case 0x10:
+					strncat(status,"10:doesn'tExist", DBD15STATLEN);
+					break;
+				case 0x11:
+					strncat(status,"11:lockAgain", DBD15STATLEN);
+					break;
+				case 0x12:
+					strncat(status,"12:locked", DBD15STATLEN);
+					break;
+				case 0x13:
+					strncat(status,"13:progErr", DBD15STATLEN);
+					break;
+				case 0x14:
+					strncat(status,"14:lockErr", DBD15STATLEN);
+					break;
+				default:
+					strncat(status,"unknownErr", DBD15STATLEN);
+			}
+			strncat(status," ", DBD15STATLEN);
+		} else {
+			strncat(status,"NoErr ", DBD15STATLEN);
+		}
+
+		crc=Crc(d,len-2);
+		if ( (( crc & 0xff ) == d[len-2]) && (( crc >> 8 ) == d[len-1]) )
+			strncat(status,"CrcOK",DBD15STATLEN);
+		else
+			strncat(status,"CrcFail!",DBD15STATLEN);
+
+		Dbprintf("%s",status);
+	}
+}
+
+
+
+///////////////////////////////////////////////////////////////////////
+// Functions called via USB/Client
+///////////////////////////////////////////////////////////////////////
+
+void SetDebugIso15693(uint32_t debug) {
+	DEBUG=debug;
+	Dbprintf("Iso15693 Debug is now %s",DEBUG?"on":"off");
+	return;
+}
+
+
+//-----------------------------------------------------------------------------
+// Simulate an ISO15693 reader, perform anti-collision and then attempt to read a sector
+// all demodulation performed in arm rather than host. - greg
+//-----------------------------------------------------------------------------
+void ReaderIso15693(uint32_t parameter)
+{
+	LEDsoff();
+	LED_A_ON();
+
+	set_tracing(true);
+	
+	int answerLen = 0;
+	uint8_t TagUID[8] = {0x00};
+
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+
+	uint8_t answer[ISO15693_MAX_RESPONSE_LENGTH];
+
+	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+	// Setup SSC
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+
+	// Start from off (no field generated)
+   	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+   	SpinDelay(200);
+
+	// Give the tags time to energize
+	LED_D_ON();
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
+	SpinDelay(200);
+	StartCountSspClk();
+
+
+	// FIRST WE RUN AN INVENTORY TO GET THE TAG UID
+	// THIS MEANS WE CAN PRE-BUILD REQUESTS TO SAVE CPU TIME
+
+	// Now send the IDENTIFY command
+	BuildIdentifyRequest();
+	TransmitTo15693Tag(ToSend, ToSendMax, 0);
+
+	// Now wait for a response
+	answerLen = GetIso15693AnswerFromTag(answer, sizeof(answer), DELAY_ISO15693_VCD_TO_VICC * 2) ;
+	uint32_t start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD;
+
+	if (answerLen >=12) // we should do a better check than this
+	{
+		TagUID[0] = answer[2];
+		TagUID[1] = answer[3];
+		TagUID[2] = answer[4];
+		TagUID[3] = answer[5];
+		TagUID[4] = answer[6];
+		TagUID[5] = answer[7];
+		TagUID[6] = answer[8]; // IC Manufacturer code
+		TagUID[7] = answer[9]; // always E0
+
+	}
+
+	Dbprintf("%d octets read from IDENTIFY request:", answerLen);
+	DbdecodeIso15693Answer(answerLen, answer);
+	Dbhexdump(answerLen, answer, false);
+
+	// UID is reverse
+	if (answerLen >= 12)
+		Dbprintf("UID = %02hX%02hX%02hX%02hX%02hX%02hX%02hX%02hX",
+			TagUID[7],TagUID[6],TagUID[5],TagUID[4],
+			TagUID[3],TagUID[2],TagUID[1],TagUID[0]);
+
+
+	// Dbprintf("%d octets read from SELECT request:", answerLen2);
+	// DbdecodeIso15693Answer(answerLen2,answer2);
+	// Dbhexdump(answerLen2,answer2,true);
+
+	// Dbprintf("%d octets read from XXX request:", answerLen3);
+	// DbdecodeIso15693Answer(answerLen3,answer3);
+	// Dbhexdump(answerLen3,answer3,true);
+
+	// read all pages
+	if (answerLen >= 12 && DEBUG) {
+
+		// debugptr = BigBuf_get_addr();
+
+		int i = 0;
+		while (i < 32) {  // 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 * 2);
+			start_time = GetCountSspClk() + DELAY_ISO15693_VICC_TO_VCD;
+			if (answerLen > 0) {
+				Dbprintf("READ SINGLE BLOCK %d returned %d octets:", i, answerLen);
+				DbdecodeIso15693Answer(answerLen, answer);
+				Dbhexdump(answerLen, answer, false);
+				if ( *((uint32_t*) answer) == 0x07160101 ) break; // exit on NoPageErr
+			}
+			i++;
+		}
+	}
+
+	// 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();
+}
+
+
+// Simulate an ISO15693 TAG.
+// For Inventory command: print command and send Inventory Response with given UID
+// TODO: interpret other reader commands and send appropriate response
+void SimTagIso15693(uint32_t parameter, uint8_t *uid)
+{
+	LEDsoff();
+	LED_A_ON();
+
+	FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+	SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
+   	FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_SIMULATOR | FPGA_HF_SIMULATOR_NO_MODULATION);
+	FpgaSetupSsc(FPGA_MAJOR_MODE_HF_SIMULATOR);
+
+	StartCountSspClk();
+
+	uint8_t cmd[ISO15693_MAX_COMMAND_LENGTH];
+
+	// Build a suitable response to the reader INVENTORY command
+	BuildInventoryResponse(uid);
+
+	// Listen to reader
+	while (!BUTTON_PRESS()) {
+		uint32_t eof_time = 0, start_time = 0;
+		int cmd_len = GetIso15693CommandFromReader(cmd, sizeof(cmd), &eof_time);
+
+		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 - DELAY_ARM_TO_READER;
+			TransmitTo15693Reader(ToSend, ToSendMax, start_time, slow);
+		}
+
+		Dbprintf("%d bytes read from reader:", cmd_len);
+		Dbhexdump(cmd_len, cmd, false);
+	}
+
+	LEDsoff();
+}
+
+
+// Since there is no standardized way of reading the AFI out of a tag, we will brute force it
+// (some manufactures offer a way to read the AFI, though)
+void BruteforceIso15693Afi(uint32_t speed)
+{
+	LEDsoff();
+	LED_A_ON();
+
+	uint8_t data[6];
+	uint8_t recv[ISO15693_MAX_RESPONSE_LENGTH];
+	
+	int datalen=0, recvlen=0;
+
+	Iso15693InitReader();
+	StartCountSspClk();
+	
+	// first without AFI
+	// Tags should respond without AFI and with AFI=0 even when AFI is active
+
+	data[0] = ISO15693_REQ_DATARATE_HIGH | ISO15693_REQ_INVENTORY | ISO15693_REQINV_SLOT1;
+	data[1] = ISO15693_INVENTORY;
+	data[2] = 0; // mask length
+	datalen = AddCrc(data,3);
+	recvlen = SendDataTag(data, datalen, false, speed, recv, sizeof(recv), 0);
+	uint32_t start_time = GetCountSspClk() + DELAY_ISO15693_VCD_TO_VICC;
+	WDT_HIT();
+	if (recvlen>=12) {
+		Dbprintf("NoAFI UID=%s", sprintUID(NULL, &recv[2]));
+	}
+
+	// now with AFI
+
+	data[0] = ISO15693_REQ_DATARATE_HIGH | ISO15693_REQ_INVENTORY | ISO15693_REQINV_AFI | ISO15693_REQINV_SLOT1;
+	data[1] = ISO15693_INVENTORY;
+	data[2] = 0; // AFI
+	data[3] = 0; // mask length
+
+	for (int i = 0; i < 256; i++) {
+		data[2] = i & 0xFF;
+		datalen = AddCrc(data,4);
+		recvlen = SendDataTag(data, datalen, false, speed, recv, sizeof(recv), start_time);
+		start_time = GetCountSspClk() + DELAY_ISO15693_VCD_TO_VICC;
+		WDT_HIT();
+		if (recvlen >= 12) {
+			Dbprintf("AFI=%i UID=%s", i, sprintUID(NULL, &recv[2]));
+		}
+	}
+	Dbprintf("AFI Bruteforcing done.");
+
+   	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	LEDsoff();
+}
+
+// Allows to directly send commands to the tag via the client
+void DirectTag15693Command(uint32_t datalen, uint32_t speed, uint32_t recv, uint8_t data[]) {
+
+	int recvlen = 0;
+	uint8_t recvbuf[ISO15693_MAX_RESPONSE_LENGTH];
+
+	LED_A_ON();
+
+	if (DEBUG) {
+		Dbprintf("SEND:");
+		Dbhexdump(datalen, data, false);
+	}
+
+	recvlen = SendDataTag(data, datalen, true, speed, (recv?recvbuf:NULL), sizeof(recvbuf), 0);
+
+	if (recv) {
+		if (DEBUG) {
+			Dbprintf("RECV:");
+			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);
+
+	}
+
+	// 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();
+}
+
+
+
+
+// --------------------------------------------------------------------
+// -- Misc & deprecated functions
+// --------------------------------------------------------------------
+
+/*
+
+// do not use; has a fix UID
+static void __attribute__((unused)) BuildSysInfoRequest(uint8_t *uid)
+{
+	uint8_t cmd[12];
+
+	uint16_t crc;
+	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
+	// followed by teh block data
+	// one sub-carrier, inventory, 1 slot, fast rate
+	cmd[0] =  (1 << 5) | (1 << 1); // no SELECT bit
+	// System Information command code
+	cmd[1] = 0x2B;
+	// UID may be optionally specified here
+	// 64-bit UID
+	cmd[2] = 0x32;
+	cmd[3]= 0x4b;
+	cmd[4] = 0x03;
+	cmd[5] = 0x01;
+	cmd[6] = 0x00;
+	cmd[7] = 0x10;
+	cmd[8] = 0x05;
+	cmd[9]= 0xe0; // always e0 (not exactly unique)
+	//Now the CRC
+	crc = Crc(cmd, 10); // the crc needs to be calculated over 2 bytes
+	cmd[10] = crc & 0xff;
+	cmd[11] = crc >> 8;
+
+	CodeIso15693AsReader(cmd, sizeof(cmd));
+}
+
+
+// do not use; has a fix UID
+static void __attribute__((unused)) BuildReadMultiBlockRequest(uint8_t *uid)
+{
+	uint8_t cmd[14];
+
+	uint16_t crc;
+	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
+	// followed by teh block data
+	// one sub-carrier, inventory, 1 slot, fast rate
+	cmd[0] =  (1 << 5) | (1 << 1); // no SELECT bit
+	// READ Multi BLOCK command code
+	cmd[1] = 0x23;
+	// UID may be optionally specified here
+	// 64-bit UID
+	cmd[2] = 0x32;
+	cmd[3]= 0x4b;
+	cmd[4] = 0x03;
+	cmd[5] = 0x01;
+	cmd[6] = 0x00;
+	cmd[7] = 0x10;
+	cmd[8] = 0x05;
+	cmd[9]= 0xe0; // always e0 (not exactly unique)
+	// First Block number to read
+	cmd[10] = 0x00;
+	// Number of Blocks to read
+	cmd[11] = 0x2f; // read quite a few
+	//Now the CRC
+	crc = Crc(cmd, 12); // the crc needs to be calculated over 2 bytes
+	cmd[12] = crc & 0xff;
+	cmd[13] = crc >> 8;
+
+	CodeIso15693AsReader(cmd, sizeof(cmd));
+}
+
+// do not use; has a fix UID
+static void __attribute__((unused)) BuildArbitraryRequest(uint8_t *uid,uint8_t CmdCode)
+{
+	uint8_t cmd[14];
+
+	uint16_t crc;
+	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
+	// followed by teh block data
+	// one sub-carrier, inventory, 1 slot, fast rate
+	cmd[0] =   (1 << 5) | (1 << 1); // no SELECT bit
+	// READ BLOCK command code
+	cmd[1] = CmdCode;
+	// UID may be optionally specified here
+	// 64-bit UID
+	cmd[2] = 0x32;
+	cmd[3]= 0x4b;
+	cmd[4] = 0x03;
+	cmd[5] = 0x01;
+	cmd[6] = 0x00;
+	cmd[7] = 0x10;
+	cmd[8] = 0x05;
+	cmd[9]= 0xe0; // always e0 (not exactly unique)
+	// Parameter
+	cmd[10] = 0x00;
+	cmd[11] = 0x0a;
+
+//	cmd[12] = 0x00;
+//	cmd[13] = 0x00;	//Now the CRC
+	crc = Crc(cmd, 12); // the crc needs to be calculated over 2 bytes
+	cmd[12] = crc & 0xff;
+	cmd[13] = crc >> 8;
+
+	CodeIso15693AsReader(cmd, sizeof(cmd));
+}
+
+// do not use; has a fix UID
+static void __attribute__((unused)) BuildArbitraryCustomRequest(uint8_t uid[], uint8_t CmdCode)
+{
+	uint8_t cmd[14];
+
+	uint16_t crc;
+	// If we set the Option_Flag in this request, the VICC will respond with the secuirty status of the block
+	// followed by teh block data
+	// one sub-carrier, inventory, 1 slot, fast rate
+	cmd[0] =   (1 << 5) | (1 << 1); // no SELECT bit
+	// READ BLOCK command code
+	cmd[1] = CmdCode;
+	// UID may be optionally specified here
+	// 64-bit UID
+	cmd[2] = 0x32;
+	cmd[3]= 0x4b;
+	cmd[4] = 0x03;
+	cmd[5] = 0x01;
+	cmd[6] = 0x00;
+	cmd[7] = 0x10;
+	cmd[8] = 0x05;
+	cmd[9]= 0xe0; // always e0 (not exactly unique)
+	// Parameter
+	cmd[10] = 0x05; // for custom codes this must be manufcturer code
+	cmd[11] = 0x00;
+
+//	cmd[12] = 0x00;
+//	cmd[13] = 0x00;	//Now the CRC
+	crc = Crc(cmd, 12); // the crc needs to be calculated over 2 bytes
+	cmd[12] = crc & 0xff;
+	cmd[13] = crc >> 8;
+
+	CodeIso15693AsReader(cmd, sizeof(cmd));
+}
+
+
+
+
+*/
+
+