X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/6f5cb60c46af439ef5d0246f1b34d65bc19eb44d..d13dee9046acdaa599e224f0a8546054eb818c6e:/armsrc/lfops.c?ds=sidebyside

diff --git a/armsrc/lfops.c b/armsrc/lfops.c
index 6c9a36f7..5ef01dcf 100644
--- a/armsrc/lfops.c
+++ b/armsrc/lfops.c
@@ -1,990 +1,1274 @@
-//-----------------------------------------------------------------------------
-// Miscellaneous routines for low frequency tag operations.
-// Tags supported here so far are Texas Instruments (TI), HID
-// Also routines for raw mode reading/simulating of LF waveform
-//
-//-----------------------------------------------------------------------------
-#include <proxmark3.h>
-#include "apps.h"
-#include "hitag2.h"
-#include "../common/crc16.c"
-
-int sprintf(char *dest, const char *fmt, ...);
-
-void AcquireRawAdcSamples125k(BOOL at134khz)
-{
-	if(at134khz) {
-		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-	} else {
-		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-	}
-
-	// Connect the A/D to the peak-detected low-frequency path.
-	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
-
-	// Give it a bit of time for the resonant antenna to settle.
-	SpinDelay(50);
-
-	// Now set up the SSC to get the ADC samples that are now streaming at us.
-	FpgaSetupSsc();
-
-	// Now call the acquisition routine
-	DoAcquisition125k(at134khz);
-}
-
-// split into two routines so we can avoid timing issues after sending commands //
-void DoAcquisition125k(BOOL at134khz)
-{
-	BYTE *dest = (BYTE *)BigBuf;
-	int n = sizeof(BigBuf);
-	int i;
-	char output_string[64];
-	
-	memset(dest,0,n);
-	i = 0;
-	for(;;) {
-		if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
-			AT91C_BASE_SSC->SSC_THR = 0x43;
-			LED_D_ON();
-		}
-		if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
-			dest[i] = (BYTE)AT91C_BASE_SSC->SSC_RHR;
-			i++;
-			LED_D_OFF();
-			if (i >= n) break;
-		}
-	}
-	sprintf(output_string, "read samples, dest[0]=%x dest[1]=%x at134khz=%d",
-		dest[0], dest[1], at134khz);
-	DbpString(output_string);
-}
-
-void ModThenAcquireRawAdcSamples125k(int delay_off,int period_0,int period_1,BYTE *command)
-{
-	BOOL at134khz;
-
-	/* Make sure the tag is reset */
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	SpinDelay(2500);
-	
-	// see if 'h' was specified
-	if(command[strlen((char *) command) - 1] == 'h')
-		at134khz= TRUE;
-	else
-		at134khz= FALSE;
-
-	if(at134khz) {
-		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-	} else {
-		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-	}
-
-	// Give it a bit of time for the resonant antenna to settle.
-	SpinDelay(50);
-	// And a little more time for the tag to fully power up
-	SpinDelay(2000);
-
-	// Now set up the SSC to get the ADC samples that are now streaming at us.
-	FpgaSetupSsc();
-
-	// now modulate the reader field
-	while(*command != '\0' && *command != ' ')
-		{
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-		LED_D_OFF();
-		SpinDelayUs(delay_off);
-		if(at134khz) {
-			FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
-			FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-		} else {
-			FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-			FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-		}
-		LED_D_ON();
-		if(*(command++) == '0') {
-			SpinDelayUs(period_0);
-		} else {
-			SpinDelayUs(period_1);
-		}
-		}
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	LED_D_OFF();
-	SpinDelayUs(delay_off);
-	if(at134khz) {
-		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-	} else {
-		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-	}
-
-	// now do the read
-	DoAcquisition125k(at134khz);
-}
-
-/* blank r/w tag data stream
-...0000000000000000 01111111
-1010101010101010101010101010101010101010101010101010101010101010
-0011010010100001
-01111111
-101010101010101[0]000...
-
-[5555fe852c5555555555555555fe0000]
-*/
-void ReadTItag()
-{
-	// some hardcoded initial params
-	// when we read a TI tag we sample the zerocross line at 2Mhz
-	// TI tags modulate a 1 as 16 cycles of 123.2Khz
-	// TI tags modulate a 0 as 16 cycles of 134.2Khz
-	#define FSAMPLE 2000000
-	#define FREQLO 123200
-	#define FREQHI 134200
-
-	signed char *dest = (signed char *)BigBuf;
-	int n = sizeof(BigBuf);
-//	int *dest = GraphBuffer;
-//	int n = GraphTraceLen;
-
-	// 128 bit shift register [shift3:shift2:shift1:shift0]
-	DWORD shift3 = 0, shift2 = 0, shift1 = 0, shift0 = 0;
-
-	int i, cycles=0, samples=0;
-	// how many sample points fit in 16 cycles of each frequency
-	DWORD sampleslo = (FSAMPLE<<4)/FREQLO, sampleshi = (FSAMPLE<<4)/FREQHI;
-	// when to tell if we're close enough to one freq or another
-	DWORD threshold = (sampleslo - sampleshi + 1)>>1;
-
-	// TI tags charge at 134.2Khz
-	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
-
-	// Place FPGA in passthrough mode, in this mode the CROSS_LO line
-	// connects to SSP_DIN and the SSP_DOUT logic level controls
-	// whether we're modulating the antenna (high)
-	// or listening to the antenna (low)
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
-
-	// get TI tag data into the buffer
-	AcquireTiType();
-
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-
-	for (i=0; i<n-1; i++) {
-		// count cycles by looking for lo to hi zero crossings
-		if ( (dest[i]<0) && (dest[i+1]>0) ) {
-			cycles++;
-			// after 16 cycles, measure the frequency
-			if (cycles>15) {
-				cycles=0;
-				samples=i-samples; // number of samples in these 16 cycles
-
-				// TI bits are coming to us lsb first so shift them
-				// right through our 128 bit right shift register
-			  shift0 = (shift0>>1) | (shift1 << 31);
-			  shift1 = (shift1>>1) | (shift2 << 31);
-			  shift2 = (shift2>>1) | (shift3 << 31);
-			  shift3 >>= 1;
-
-				// check if the cycles fall close to the number
-				// expected for either the low or high frequency
-				if ( (samples>(sampleslo-threshold)) && (samples<(sampleslo+threshold)) ) {
-					// low frequency represents a 1
-					shift3 |= (1<<31);
-				} else if ( (samples>(sampleshi-threshold)) && (samples<(sampleshi+threshold)) ) {
-					// high frequency represents a 0
-				} else {
-					// probably detected a gay waveform or noise
-					// use this as gaydar or discard shift register and start again
-					shift3 = shift2 = shift1 = shift0 = 0;
-				}
-				samples = i;
-
-				// for each bit we receive, test if we've detected a valid tag
-
-				// if we see 17 zeroes followed by 6 ones, we might have a tag
-				// remember the bits are backwards
-				if ( ((shift0 & 0x7fffff) == 0x7e0000) ) {
-					// if start and end bytes match, we have a tag so break out of the loop
-					if ( ((shift0>>16)&0xff) == ((shift3>>8)&0xff) ) {
-						cycles = 0xF0B; //use this as a flag (ugly but whatever)
-						break;
-					}
-				}
-			}
-		}
-	}
-
-	// if flag is set we have a tag
-	if (cycles!=0xF0B) {
-		DbpString("Info: No valid tag detected.");
-	} else {
-	  // put 64 bit data into shift1 and shift0
-	  shift0 = (shift0>>24) | (shift1 << 8);
-	  shift1 = (shift1>>24) | (shift2 << 8);
-
-		// align 16 bit crc into lower half of shift2
-	  shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;
-
-		// if r/w tag, check ident match
-		if ( shift3&(1<<15) ) {
-			DbpString("Info: TI tag is rewriteable");
-			// only 15 bits compare, last bit of ident is not valid
-			if ( ((shift3>>16)^shift0)&0x7fff ) {
-				DbpString("Error: Ident mismatch!");
-			} else {
-				DbpString("Info: TI tag ident is valid");
-			}
-		} else {
-			DbpString("Info: TI tag is readonly");
-		}
-
-		// WARNING the order of the bytes in which we calc crc below needs checking
-		// i'm 99% sure the crc algorithm is correct, but it may need to eat the
-		// bytes in reverse or something
-		// calculate CRC
-		DWORD crc=0;
-
-	 	crc = update_crc16(crc, (shift0)&0xff);
-		crc = update_crc16(crc, (shift0>>8)&0xff);
-		crc = update_crc16(crc, (shift0>>16)&0xff);
-		crc = update_crc16(crc, (shift0>>24)&0xff);
-		crc = update_crc16(crc, (shift1)&0xff);
-		crc = update_crc16(crc, (shift1>>8)&0xff);
-		crc = update_crc16(crc, (shift1>>16)&0xff);
-		crc = update_crc16(crc, (shift1>>24)&0xff);
-
-		char output_string[64];
-		sprintf(output_string, "Info: Tag data_hi=%x, data_lo=%x, crc=%x",
-			(unsigned int)shift1, (unsigned int)shift0, (unsigned int)shift2 & 0xFFFF);
-		DbpString(output_string);
-		if (crc != (shift2&0xffff)) {
-			sprintf(output_string, "Error: CRC mismatch, expected %x", (unsigned int)crc);
-			DbpString(output_string);
-		} else {
-			DbpString("Info: CRC is good");
-		}
-	}
-}
-
-void WriteTIbyte(BYTE b)
-{
-	int i = 0;
-
-	// modulate 8 bits out to the antenna
-	for (i=0; i<8; i++)
-	{
-		if (b&(1<<i)) {
-			// stop modulating antenna
-			LOW(GPIO_SSC_DOUT);
-			SpinDelayUs(1000);
-			// modulate antenna
-			HIGH(GPIO_SSC_DOUT);
-			SpinDelayUs(1000);
-		} else {
-			// stop modulating antenna
-			LOW(GPIO_SSC_DOUT);
-			SpinDelayUs(300);
-			// modulate antenna
-			HIGH(GPIO_SSC_DOUT);
-			SpinDelayUs(1700);
-		}
-	}
-}
-
-void AcquireTiType(void)
-{
-	int i, j, n;
-	// tag transmission is <20ms, sampling at 2M gives us 40K samples max
-	// each sample is 1 bit stuffed into a DWORD so we need 1250 DWORDS
-	#define TIBUFLEN 1250
-
-	// clear buffer
-	memset(BigBuf,0,sizeof(BigBuf));
-
-	// Set up the synchronous serial port
-	AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DIN;
-	AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN;
-
-	// steal this pin from the SSP and use it to control the modulation
-	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
-	AT91C_BASE_PIOA->PIO_OER	= GPIO_SSC_DOUT;
-
-	AT91C_BASE_SSC->SSC_CR = AT91C_SSC_SWRST;
-	AT91C_BASE_SSC->SSC_CR = AT91C_SSC_RXEN | AT91C_SSC_TXEN;
-
-	// Sample at 2 Mbit/s, so TI tags are 16.2 vs. 14.9 clocks long
-	// 48/2 = 24 MHz clock must be divided by 12
-	AT91C_BASE_SSC->SSC_CMR = 12;
-
-	AT91C_BASE_SSC->SSC_RCMR = SSC_CLOCK_MODE_SELECT(0);
-	AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(32) | AT91C_SSC_MSBF;
-	AT91C_BASE_SSC->SSC_TCMR = 0;
-	AT91C_BASE_SSC->SSC_TFMR = 0;
-
-	LED_D_ON();
-
-	// modulate antenna
-	HIGH(GPIO_SSC_DOUT);
-
-	// Charge TI tag for 50ms.
-	SpinDelay(50);
-
-	// stop modulating antenna and listen
-	LOW(GPIO_SSC_DOUT);
-
-	LED_D_OFF();
-
-	i = 0;
-	for(;;) {
-		if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
-			BigBuf[i] = AT91C_BASE_SSC->SSC_RHR;	// store 32 bit values in buffer
-			i++; if(i >= TIBUFLEN) break;
-		}
-		WDT_HIT();
-	}
-
-	// return stolen pin to SSP
-	AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DOUT;
-	AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN | GPIO_SSC_DOUT;
-
-	char *dest = (char *)BigBuf;
-	n = TIBUFLEN*32;
-	// unpack buffer
-	for (i=TIBUFLEN-1; i>=0; i--) {
-//		DbpIntegers(0, 0, BigBuf[i]);
-		for (j=0; j<32; j++) {
-			if(BigBuf[i] & (1 << j)) {
-				dest[--n] = 1;
-			} else {
-				dest[--n] = -1;
-			}
-		}
-	}
-}
-
-// arguments: 64bit data split into 32bit idhi:idlo and optional 16bit crc
-// if crc provided, it will be written with the data verbatim (even if bogus)
-// if not provided a valid crc will be computed from the data and written.
-void WriteTItag(DWORD idhi, DWORD idlo, WORD crc)
-{
-
-	// WARNING the order of the bytes in which we calc crc below needs checking
-	// i'm 99% sure the crc algorithm is correct, but it may need to eat the
-	// bytes in reverse or something
-
-	if(crc == 0) {
-	 	crc = update_crc16(crc, (idlo)&0xff);
-		crc = update_crc16(crc, (idlo>>8)&0xff);
-		crc = update_crc16(crc, (idlo>>16)&0xff);
-		crc = update_crc16(crc, (idlo>>24)&0xff);
-		crc = update_crc16(crc, (idhi)&0xff);
-		crc = update_crc16(crc, (idhi>>8)&0xff);
-		crc = update_crc16(crc, (idhi>>16)&0xff);
-		crc = update_crc16(crc, (idhi>>24)&0xff);
-	}
-	char output_string[64];
-	sprintf(output_string, "Writing the following data to tag: %x, %x, %x",
-		(unsigned int) idhi, (unsigned int) idlo, crc);
-	DbpString(output_string);
-
-	// TI tags charge at 134.2Khz
-	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
-	// Place FPGA in passthrough mode, in this mode the CROSS_LO line
-	// connects to SSP_DIN and the SSP_DOUT logic level controls
-	// whether we're modulating the antenna (high)
-	// or listening to the antenna (low)
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
-	LED_A_ON();
-
-	// steal this pin from the SSP and use it to control the modulation
-	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
-	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
-
-	// writing algorithm:
-	// a high bit consists of a field off for 1ms and field on for 1ms
-	// a low bit consists of a field off for 0.3ms and field on for 1.7ms
-	// initiate a charge time of 50ms (field on) then immediately start writing bits
-	// start by writing 0xBB (keyword) and 0xEB (password)
-	// then write 80 bits of data (or 64 bit data + 16 bit crc if you prefer)
-	// finally end with 0x0300 (write frame)
-	// all data is sent lsb firts
-	// finish with 15ms programming time
-
-	// modulate antenna
-	HIGH(GPIO_SSC_DOUT);
-	SpinDelay(50);	// charge time
-
-	WriteTIbyte(0xbb); // keyword
-	WriteTIbyte(0xeb); // password
-	WriteTIbyte( (idlo    )&0xff );
-	WriteTIbyte( (idlo>>8 )&0xff );
-	WriteTIbyte( (idlo>>16)&0xff );
-	WriteTIbyte( (idlo>>24)&0xff );
-	WriteTIbyte( (idhi    )&0xff );
-	WriteTIbyte( (idhi>>8 )&0xff );
-	WriteTIbyte( (idhi>>16)&0xff );
-	WriteTIbyte( (idhi>>24)&0xff ); // data hi to lo
-	WriteTIbyte( (crc     )&0xff ); // crc lo
-	WriteTIbyte( (crc>>8  )&0xff ); // crc hi
-	WriteTIbyte(0x00); // write frame lo
-	WriteTIbyte(0x03); // write frame hi
-	HIGH(GPIO_SSC_DOUT);
-	SpinDelay(50);	// programming time
-
-	LED_A_OFF();
-
-	// get TI tag data into the buffer
-	AcquireTiType();
-
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	DbpString("Now use tiread to check");
-}
-
-void SimulateTagLowFrequency(int period, int ledcontrol)
-{
-	int i;
-	BYTE *tab = (BYTE *)BigBuf;
-
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);
-
-	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT | GPIO_SSC_CLK;
-
-	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
-	AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_CLK;
-
-#define SHORT_COIL()	LOW(GPIO_SSC_DOUT)
-#define OPEN_COIL()		HIGH(GPIO_SSC_DOUT)
-
-	i = 0;
-	for(;;) {
-		while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)) {
-			if(BUTTON_PRESS()) {
-				DbpString("Stopped");
-				return;
-			}
-			WDT_HIT();
-		}
-
-		if (ledcontrol)
-			LED_D_ON();
-
-		if(tab[i])
-			OPEN_COIL();
-		else
-			SHORT_COIL();
-
-		if (ledcontrol)
-			LED_D_OFF();
-
-		while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK) {
-			if(BUTTON_PRESS()) {
-				DbpString("Stopped");
-				return;
-			}
-			WDT_HIT();
-		}
-
-		i++;
-		if(i == period) i = 0;
-	}
-}
-
-/* Provides a framework for bidirectional LF tag communication
- * Encoding is currently Hitag2, but the general idea can probably
- * be transferred to other encodings.
- * 
- * The new FPGA code will, for the LF simulator mode, give on SSC_FRAME
- * (PA15) a thresholded version of the signal from the ADC. Setting the
- * ADC path to the low frequency peak detection signal, will enable a
- * somewhat reasonable receiver for modulation on the carrier signal
- * that is generated by the reader. The signal is low when the reader
- * field is switched off, and high when the reader field is active. Due
- * to the way that the signal looks like, mostly only the rising edge is
- * useful, your mileage may vary.
- * 
- * Neat perk: PA15 can not only be used as a bit-banging GPIO, but is also
- * TIOA1, which can be used as the capture input for timer 1. This should
- * make it possible to measure the exact edge-to-edge time, without processor
- * intervention.
- * 
- * Arguments: divisor is the divisor to be sent to the FPGA (e.g. 95 for 125kHz)
- * t0 is the carrier frequency cycle duration in terms of MCK (384 for 125kHz)
- * 
- * The following defines are in carrier periods: 
- */
-#define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */ 
-#define HITAG_T_1_MIN 24 /* T[1] should be 26..30 */
-#define HITAG_T_EOF   40 /* T_EOF should be > 36 */
-#define HITAG_T_WRESP 208 /* T_wresp should be 204..212 */
-
-static void hitag_handle_frame(int t0, int frame_len, char *frame);
-//#define DEBUG_RA_VALUES 1
-#define DEBUG_FRAME_CONTENTS 1
-void SimulateTagLowFrequencyBidir(int divisor, int t0)
-{
-#if DEBUG_RA_VALUES || DEBUG_FRAME_CONTENTS
-	int i = 0;
-#endif
-	char frame[10];
-	int frame_pos=0;
-	
-	DbpString("Starting Hitag2 emulator, press button to end");
-	hitag2_init();
-	
-	/* Set up simulator mode, frequency divisor which will drive the FPGA
-	 * and analog mux selection.
-	 */
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);
-	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
-	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
-	RELAY_OFF();
-	
-	/* Set up Timer 1:
-	 * Capture mode, timer source MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
-	 * external trigger rising edge, load RA on rising edge of TIOA, load RB on rising
-	 * edge of TIOA. Assign PA15 to TIOA1 (peripheral B)
-	 */
-	
-	AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
-	AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
-	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
-	AT91C_BASE_TC1->TC_CMR =	TC_CMR_TCCLKS_TIMER_CLOCK1 |
-								AT91C_TC_ETRGEDG_RISING |
-								AT91C_TC_ABETRG |
-								AT91C_TC_LDRA_RISING |
-								AT91C_TC_LDRB_RISING;
-	AT91C_BASE_TC1->TC_CCR =	AT91C_TC_CLKEN |
-								AT91C_TC_SWTRG;
-	
-	/* calculate the new value for the carrier period in terms of TC1 values */
-	t0 = t0/2;
-	
-	int overflow = 0;
-	while(!BUTTON_PRESS()) {
-		WDT_HIT();
-		if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
-			int ra = AT91C_BASE_TC1->TC_RA;
-			if((ra > t0*HITAG_T_EOF) | overflow) ra = t0*HITAG_T_EOF+1;
-#if DEBUG_RA_VALUES
-			if(ra > 255 || overflow) ra = 255;
-			((char*)BigBuf)[i] = ra;
-			i = (i+1) % 8000;
-#endif
-			
-			if(overflow || (ra > t0*HITAG_T_EOF) || (ra < t0*HITAG_T_0_MIN)) {
-				/* Ignore */
-			} else if(ra >= t0*HITAG_T_1_MIN ) {
-				/* '1' bit */
-				if(frame_pos < 8*sizeof(frame)) {
-					frame[frame_pos / 8] |= 1<<( 7-(frame_pos%8) );
-					frame_pos++;
-				}
-			} else if(ra >= t0*HITAG_T_0_MIN) {
-				/* '0' bit */
-				if(frame_pos < 8*sizeof(frame)) {
-					frame[frame_pos / 8] |= 0<<( 7-(frame_pos%8) );
-					frame_pos++;
-				}
-			}
-			
-			overflow = 0;
-			LED_D_ON();
-		} else {
-			if(AT91C_BASE_TC1->TC_CV > t0*HITAG_T_EOF) {
-				/* Minor nuisance: In Capture mode, the timer can not be
-				 * stopped by a Compare C. There's no way to stop the clock
-				 * in software, so we'll just have to note the fact that an
-				 * overflow happened and the next loaded timer value might
-				 * have wrapped. Also, this marks the end of frame, and the
-				 * still running counter can be used to determine the correct
-				 * time for the start of the reply.
-				 */ 
-				overflow = 1;
-				
-				if(frame_pos > 0) {
-					/* Have a frame, do something with it */
-#if DEBUG_FRAME_CONTENTS
-					((char*)BigBuf)[i++] = frame_pos;
-					memcpy( ((char*)BigBuf)+i, frame, 7);
-					i+=7;
-					i = i % sizeof(BigBuf);
-#endif
-					hitag_handle_frame(t0, frame_pos, frame);
-					memset(frame, 0, sizeof(frame));
-				}
-				frame_pos = 0;
-
-			}
-			LED_D_OFF();
-		}
-	}
-	DbpString("All done");
-}
-
-static void hitag_send_bit(int t0, int bit) {
-	if(bit == 1) {
-		/* Manchester: Loaded, then unloaded */
-		LED_A_ON();
-		SHORT_COIL();
-		while(AT91C_BASE_TC1->TC_CV < t0*15);
-		OPEN_COIL();
-		while(AT91C_BASE_TC1->TC_CV < t0*31);
-		LED_A_OFF();
-	} else if(bit == 0) {
-		/* Manchester: Unloaded, then loaded */
-		LED_B_ON();
-		OPEN_COIL();
-		while(AT91C_BASE_TC1->TC_CV < t0*15);
-		SHORT_COIL();
-		while(AT91C_BASE_TC1->TC_CV < t0*31);
-		LED_B_OFF();
-	}
-	AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; /* Reset clock for the next bit */
-	
-}
-static void hitag_send_frame(int t0, int frame_len, const char const * frame, int fdt)
-{
-	OPEN_COIL();
-	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
-	
-	/* Wait for HITAG_T_WRESP carrier periods after the last reader bit,
-	 * not that since the clock counts since the rising edge, but T_wresp is
-	 * with respect to the falling edge, we need to wait actually (T_wresp - T_g)
-	 * periods. The gap time T_g varies (4..10).
-	 */
-	while(AT91C_BASE_TC1->TC_CV < t0*(fdt-8));
-
-	int saved_cmr = AT91C_BASE_TC1->TC_CMR;
-	AT91C_BASE_TC1->TC_CMR &= ~AT91C_TC_ETRGEDG; /* Disable external trigger for the clock */
-	AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; /* Reset the clock and use it for response timing */
-	
-	int i;
-	for(i=0; i<5; i++)
-		hitag_send_bit(t0, 1); /* Start of frame */
-	
-	for(i=0; i<frame_len; i++) {
-		hitag_send_bit(t0, !!(frame[i/ 8] & (1<<( 7-(i%8) ))) );
-	}
-	
-	OPEN_COIL();
-	AT91C_BASE_TC1->TC_CMR = saved_cmr;
-}
-
-/* Callback structure to cleanly separate tag emulation code from the radio layer. */
-static int hitag_cb(const char* response_data, const int response_length, const int fdt, void *cb_cookie)
-{
-	hitag_send_frame(*(int*)cb_cookie, response_length, response_data, fdt);
-	return 0;
-}
-/* Frame length in bits, frame contents in MSBit first format */
-static void hitag_handle_frame(int t0, int frame_len, char *frame)
-{
-	hitag2_handle_command(frame, frame_len, hitag_cb, &t0);
-}
-
-// compose fc/8 fc/10 waveform
-static void fc(int c, int *n) {
-	BYTE *dest = (BYTE *)BigBuf;
-	int idx;
-
-	// for when we want an fc8 pattern every 4 logical bits
-	if(c==0) {
-		dest[((*n)++)]=1;
-		dest[((*n)++)]=1;
-		dest[((*n)++)]=0;
-		dest[((*n)++)]=0;
-		dest[((*n)++)]=0;
-		dest[((*n)++)]=0;
-		dest[((*n)++)]=0;
-		dest[((*n)++)]=0;
-	}
-	//	an fc/8  encoded bit is a bit pattern of  11000000  x6 = 48 samples
-	if(c==8) {
-		for (idx=0; idx<6; idx++) {
-			dest[((*n)++)]=1;
-			dest[((*n)++)]=1;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-		}
-	}
-
-	//	an fc/10 encoded bit is a bit pattern of 1110000000 x5 = 50 samples
-	if(c==10) {
-		for (idx=0; idx<5; idx++) {
-			dest[((*n)++)]=1;
-			dest[((*n)++)]=1;
-			dest[((*n)++)]=1;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-			dest[((*n)++)]=0;
-		}
-	}
-}
-
-// prepare a waveform pattern in the buffer based on the ID given then
-// simulate a HID tag until the button is pressed
-void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
-{
-	int n=0, i=0;
-	/*
-	 HID tag bitstream format
-	 The tag contains a 44bit unique code. This is sent out MSB first in sets of 4 bits
-	 A 1 bit is represented as 6 fc8 and 5 fc10 patterns
-	 A 0 bit is represented as 5 fc10 and 6 fc8 patterns
-	 A fc8 is inserted before every 4 bits
-	 A special start of frame pattern is used consisting a0b0 where a and b are neither 0
-	 nor 1 bits, they are special patterns (a = set of 12 fc8 and b = set of 10 fc10)
-	*/
-
-	if (hi>0xFFF) {
-		DbpString("Tags can only have 44 bits.");
-		return;
-	}
-	fc(0,&n);
-	// special start of frame marker containing invalid bit sequences
-	fc(8,  &n);	fc(8,  &n);	// invalid
-	fc(8,  &n);	fc(10, &n); // logical 0
-	fc(10, &n);	fc(10, &n); // invalid
-	fc(8,  &n);	fc(10, &n); // logical 0
-
-	WDT_HIT();
-	// manchester encode bits 43 to 32
-	for (i=11; i>=0; i--) {
-		if ((i%4)==3) fc(0,&n);
-		if ((hi>>i)&1) {
-			fc(10, &n);	fc(8,  &n);		// low-high transition
-		} else {
-			fc(8,  &n);	fc(10, &n);		// high-low transition
-		}
-	}
-
-	WDT_HIT();
-	// manchester encode bits 31 to 0
-	for (i=31; i>=0; i--) {
-		if ((i%4)==3) fc(0,&n);
-		if ((lo>>i)&1) {
-			fc(10, &n);	fc(8,  &n);		// low-high transition
-		} else {
-			fc(8,  &n);	fc(10, &n);		// high-low transition
-		}
-	}
-
-	if (ledcontrol)
-		LED_A_ON();
-	SimulateTagLowFrequency(n, ledcontrol);
-
-	if (ledcontrol)
-		LED_A_OFF();
-}
-
-
-// loop to capture raw HID waveform then FSK demodulate the TAG ID from it
-void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
-{
-	BYTE *dest = (BYTE *)BigBuf;
-	int m=0, n=0, i=0, idx=0, found=0, lastval=0;
-	DWORD hi=0, lo=0;
-
-	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
-
-	// Connect the A/D to the peak-detected low-frequency path.
-	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
-
-	// Give it a bit of time for the resonant antenna to settle.
-	SpinDelay(50);
-
-	// Now set up the SSC to get the ADC samples that are now streaming at us.
-	FpgaSetupSsc();
-
-	for(;;) {
-		WDT_HIT();
-		if (ledcontrol)
-			LED_A_ON();
-		if(BUTTON_PRESS()) {
-			DbpString("Stopped");
-			if (ledcontrol)
-				LED_A_OFF();
-			return;
-		}
-
-		i = 0;
-		m = sizeof(BigBuf);
-		memset(dest,128,m);
-		for(;;) {
-			if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
-				AT91C_BASE_SSC->SSC_THR = 0x43;
-				if (ledcontrol)
-					LED_D_ON();
-			}
-			if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
-				dest[i] = (BYTE)AT91C_BASE_SSC->SSC_RHR;
-				// we don't care about actual value, only if it's more or less than a
-				// threshold essentially we capture zero crossings for later analysis
-				if(dest[i] < 127) dest[i] = 0; else dest[i] = 1;
-				i++;
-				if (ledcontrol)
-					LED_D_OFF();
-				if(i >= m) {
-					break;
-				}
-			}
-		}
-
-		// FSK demodulator
-
-		// sync to first lo-hi transition
-		for( idx=1; idx<m; idx++) {
-			if (dest[idx-1]<dest[idx])
-				lastval=idx;
-				break;
-		}
-		WDT_HIT();
-
-		// count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
-		// or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
-		// between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
-		for( i=0; idx<m; idx++) {
-			if (dest[idx-1]<dest[idx]) {
-				dest[i]=idx-lastval;
-				if (dest[i] <= 8) {
-						dest[i]=1;
-				} else {
-						dest[i]=0;
-				}
-
-				lastval=idx;
-				i++;
-			}
-		}
-		m=i;
-		WDT_HIT();
-
-		// we now have a set of cycle counts, loop over previous results and aggregate data into bit patterns
-		lastval=dest[0];
-		idx=0;
-		i=0;
-		n=0;
-		for( idx=0; idx<m; idx++) {
-			if (dest[idx]==lastval) {
-				n++;
-			} else {
-				// a bit time is five fc/10 or six fc/8 cycles so figure out how many bits a pattern width represents,
-				// an extra fc/8 pattern preceeds every 4 bits (about 200 cycles) just to complicate things but it gets
-				// swallowed up by rounding
-				// expected results are 1 or 2 bits, any more and it's an invalid manchester encoding
-				// special start of frame markers use invalid manchester states (no transitions) by using sequences
-				// like 111000
-				if (dest[idx-1]) {
-					n=(n+1)/6;			// fc/8 in sets of 6
-				} else {
-					n=(n+1)/5;			// fc/10 in sets of 5
-				}
-				switch (n) {			// stuff appropriate bits in buffer
-					case 0:
-					case 1:	// one bit
-						dest[i++]=dest[idx-1];
-						break;
-					case 2: // two bits
-						dest[i++]=dest[idx-1];
-						dest[i++]=dest[idx-1];
-						break;
-					case 3: // 3 bit start of frame markers
-						dest[i++]=dest[idx-1];
-						dest[i++]=dest[idx-1];
-						dest[i++]=dest[idx-1];
-						break;
-					// When a logic 0 is immediately followed by the start of the next transmisson
-					// (special pattern) a pattern of 4 bit duration lengths is created.
-					case 4:
-						dest[i++]=dest[idx-1];
-						dest[i++]=dest[idx-1];
-						dest[i++]=dest[idx-1];
-						dest[i++]=dest[idx-1];
-						break;
-					default:	// this shouldn't happen, don't stuff any bits
-						break;
-				}
-				n=0;
-				lastval=dest[idx];
-			}
-		}
-		m=i;
-		WDT_HIT();
-
-		// final loop, go over previously decoded manchester data and decode into usable tag ID
-		// 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0
-		for( idx=0; idx<m-6; idx++) {
-			// search for a start of frame marker
-			if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
-			{
-				found=1;
-				idx+=6;
-				if (found && (hi|lo)) {
-					char output_string[64];
-					sprintf(output_string, "TAG ID: %x %x %x", 
-						(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
-					DbpString(output_string);
-					/* if we're only looking for one tag */
-					if (findone)
-					{
-						*high = hi;
-						*low = lo;
-						return;
-					}
-					hi=0;
-					lo=0;
-					found=0;
-				}
-			}
-			if (found) {
-				if (dest[idx] && (!dest[idx+1]) ) {
-					hi=(hi<<1)|(lo>>31);
-					lo=(lo<<1)|0;
-				} else if ( (!dest[idx]) && dest[idx+1]) {
-					hi=(hi<<1)|(lo>>31);
-					lo=(lo<<1)|1;
-				} else {
-					found=0;
-					hi=0;
-					lo=0;
-				}
-				idx++;
-			}
-			if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
-			{
-				found=1;
-				idx+=6;
-				if (found && (hi|lo)) {
-					char output_string[64];
-					sprintf(output_string, "TAG ID: %x %x %x", 
-						(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
-					DbpString(output_string);
-					/* if we're only looking for one tag */
-					if (findone)
-					{
-						*high = hi;
-						*low = lo;
-						return;
-					}
-					hi=0;
-					lo=0;
-					found=0;
-				}
-			}
-		}
-		WDT_HIT();
-	}
-}
+//-----------------------------------------------------------------------------
+// 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.
+//-----------------------------------------------------------------------------
+// Miscellaneous routines for low frequency tag operations.
+// Tags supported here so far are Texas Instruments (TI), HID
+// Also routines for raw mode reading/simulating of LF waveform
+//-----------------------------------------------------------------------------
+
+#include "proxmark3.h"
+#include "apps.h"
+#include "util.h"
+#include "hitag2.h"
+#include "crc16.h"
+#include "string.h"
+
+void AcquireRawAdcSamples125k(int at134khz)
+{
+	if (at134khz)
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+	else
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+
+	// Connect the A/D to the peak-detected low-frequency path.
+	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+
+	// Give it a bit of time for the resonant antenna to settle.
+	SpinDelay(50);
+
+	// Now set up the SSC to get the ADC samples that are now streaming at us.
+	FpgaSetupSsc();
+
+	// Now call the acquisition routine
+	DoAcquisition125k();
+}
+
+// split into two routines so we can avoid timing issues after sending commands //
+void DoAcquisition125k(void)
+{
+	uint8_t *dest = (uint8_t *)BigBuf;
+	int n = sizeof(BigBuf);
+	int i;
+
+	memset(dest, 0, n);
+	i = 0;
+	for(;;) {
+		if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+			AT91C_BASE_SSC->SSC_THR = 0x43;
+			LED_D_ON();
+		}
+		if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+			dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+			i++;
+			LED_D_OFF();
+			if (i >= n) break;
+		}
+	}
+	Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
+			dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
+}
+
+void ModThenAcquireRawAdcSamples125k(int delay_off, int period_0, int period_1, uint8_t *command)
+{
+	int at134khz;
+
+	/* Make sure the tag is reset */
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	SpinDelay(2500);
+
+	// see if 'h' was specified
+	if (command[strlen((char *) command) - 1] == 'h')
+		at134khz = TRUE;
+	else
+		at134khz = FALSE;
+
+	if (at134khz)
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+	else
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+
+	// Give it a bit of time for the resonant antenna to settle.
+	SpinDelay(50);
+	// And a little more time for the tag to fully power up
+	SpinDelay(2000);
+
+	// Now set up the SSC to get the ADC samples that are now streaming at us.
+	FpgaSetupSsc();
+
+	// now modulate the reader field
+	while(*command != '\0' && *command != ' ') {
+		FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+		LED_D_OFF();
+		SpinDelayUs(delay_off);
+		if (at134khz)
+			FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+		else
+			FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+
+		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+		LED_D_ON();
+		if(*(command++) == '0')
+			SpinDelayUs(period_0);
+		else
+			SpinDelayUs(period_1);
+	}
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	LED_D_OFF();
+	SpinDelayUs(delay_off);
+	if (at134khz)
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+	else
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+
+	// now do the read
+	DoAcquisition125k();
+}
+
+/* blank r/w tag data stream
+...0000000000000000 01111111
+1010101010101010101010101010101010101010101010101010101010101010
+0011010010100001
+01111111
+101010101010101[0]000...
+
+[5555fe852c5555555555555555fe0000]
+*/
+void ReadTItag(void)
+{
+	// some hardcoded initial params
+	// when we read a TI tag we sample the zerocross line at 2Mhz
+	// TI tags modulate a 1 as 16 cycles of 123.2Khz
+	// TI tags modulate a 0 as 16 cycles of 134.2Khz
+	#define FSAMPLE 2000000
+	#define FREQLO 123200
+	#define FREQHI 134200
+
+	signed char *dest = (signed char *)BigBuf;
+	int n = sizeof(BigBuf);
+//	int *dest = GraphBuffer;
+//	int n = GraphTraceLen;
+
+	// 128 bit shift register [shift3:shift2:shift1:shift0]
+	uint32_t shift3 = 0, shift2 = 0, shift1 = 0, shift0 = 0;
+
+	int i, cycles=0, samples=0;
+	// how many sample points fit in 16 cycles of each frequency
+	uint32_t sampleslo = (FSAMPLE<<4)/FREQLO, sampleshi = (FSAMPLE<<4)/FREQHI;
+	// when to tell if we're close enough to one freq or another
+	uint32_t threshold = (sampleslo - sampleshi + 1)>>1;
+
+	// TI tags charge at 134.2Khz
+	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+
+	// Place FPGA in passthrough mode, in this mode the CROSS_LO line
+	// connects to SSP_DIN and the SSP_DOUT logic level controls
+	// whether we're modulating the antenna (high)
+	// or listening to the antenna (low)
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
+
+	// get TI tag data into the buffer
+	AcquireTiType();
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+
+	for (i=0; i<n-1; i++) {
+		// count cycles by looking for lo to hi zero crossings
+		if ( (dest[i]<0) && (dest[i+1]>0) ) {
+			cycles++;
+			// after 16 cycles, measure the frequency
+			if (cycles>15) {
+				cycles=0;
+				samples=i-samples; // number of samples in these 16 cycles
+
+				// TI bits are coming to us lsb first so shift them
+				// right through our 128 bit right shift register
+			  shift0 = (shift0>>1) | (shift1 << 31);
+			  shift1 = (shift1>>1) | (shift2 << 31);
+			  shift2 = (shift2>>1) | (shift3 << 31);
+			  shift3 >>= 1;
+
+				// check if the cycles fall close to the number
+				// expected for either the low or high frequency
+				if ( (samples>(sampleslo-threshold)) && (samples<(sampleslo+threshold)) ) {
+					// low frequency represents a 1
+					shift3 |= (1<<31);
+				} else if ( (samples>(sampleshi-threshold)) && (samples<(sampleshi+threshold)) ) {
+					// high frequency represents a 0
+				} else {
+					// probably detected a gay waveform or noise
+					// use this as gaydar or discard shift register and start again
+					shift3 = shift2 = shift1 = shift0 = 0;
+				}
+				samples = i;
+
+				// for each bit we receive, test if we've detected a valid tag
+
+				// if we see 17 zeroes followed by 6 ones, we might have a tag
+				// remember the bits are backwards
+				if ( ((shift0 & 0x7fffff) == 0x7e0000) ) {
+					// if start and end bytes match, we have a tag so break out of the loop
+					if ( ((shift0>>16)&0xff) == ((shift3>>8)&0xff) ) {
+						cycles = 0xF0B; //use this as a flag (ugly but whatever)
+						break;
+					}
+				}
+			}
+		}
+	}
+
+	// if flag is set we have a tag
+	if (cycles!=0xF0B) {
+		DbpString("Info: No valid tag detected.");
+	} else {
+	  // put 64 bit data into shift1 and shift0
+	  shift0 = (shift0>>24) | (shift1 << 8);
+	  shift1 = (shift1>>24) | (shift2 << 8);
+
+		// align 16 bit crc into lower half of shift2
+	  shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff;
+
+		// if r/w tag, check ident match
+		if ( shift3&(1<<15) ) {
+			DbpString("Info: TI tag is rewriteable");
+			// only 15 bits compare, last bit of ident is not valid
+			if ( ((shift3>>16)^shift0)&0x7fff ) {
+				DbpString("Error: Ident mismatch!");
+			} else {
+				DbpString("Info: TI tag ident is valid");
+			}
+		} else {
+			DbpString("Info: TI tag is readonly");
+		}
+
+		// WARNING the order of the bytes in which we calc crc below needs checking
+		// i'm 99% sure the crc algorithm is correct, but it may need to eat the
+		// bytes in reverse or something
+		// calculate CRC
+		uint32_t crc=0;
+
+	 	crc = update_crc16(crc, (shift0)&0xff);
+		crc = update_crc16(crc, (shift0>>8)&0xff);
+		crc = update_crc16(crc, (shift0>>16)&0xff);
+		crc = update_crc16(crc, (shift0>>24)&0xff);
+		crc = update_crc16(crc, (shift1)&0xff);
+		crc = update_crc16(crc, (shift1>>8)&0xff);
+		crc = update_crc16(crc, (shift1>>16)&0xff);
+		crc = update_crc16(crc, (shift1>>24)&0xff);
+
+		Dbprintf("Info: Tag data: %x%08x, crc=%x",
+			(unsigned int)shift1, (unsigned int)shift0, (unsigned int)shift2 & 0xFFFF);
+		if (crc != (shift2&0xffff)) {
+			Dbprintf("Error: CRC mismatch, expected %x", (unsigned int)crc);
+		} else {
+			DbpString("Info: CRC is good");
+		}
+	}
+}
+
+void WriteTIbyte(uint8_t b)
+{
+	int i = 0;
+
+	// modulate 8 bits out to the antenna
+	for (i=0; i<8; i++)
+	{
+		if (b&(1<<i)) {
+			// stop modulating antenna
+			LOW(GPIO_SSC_DOUT);
+			SpinDelayUs(1000);
+			// modulate antenna
+			HIGH(GPIO_SSC_DOUT);
+			SpinDelayUs(1000);
+		} else {
+			// stop modulating antenna
+			LOW(GPIO_SSC_DOUT);
+			SpinDelayUs(300);
+			// modulate antenna
+			HIGH(GPIO_SSC_DOUT);
+			SpinDelayUs(1700);
+		}
+	}
+}
+
+void AcquireTiType(void)
+{
+	int i, j, n;
+	// tag transmission is <20ms, sampling at 2M gives us 40K samples max
+	// each sample is 1 bit stuffed into a uint32_t so we need 1250 uint32_t
+	#define TIBUFLEN 1250
+
+	// clear buffer
+	memset(BigBuf,0,sizeof(BigBuf));
+
+	// Set up the synchronous serial port
+	AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DIN;
+	AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN;
+
+	// steal this pin from the SSP and use it to control the modulation
+	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+
+	AT91C_BASE_SSC->SSC_CR = AT91C_SSC_SWRST;
+	AT91C_BASE_SSC->SSC_CR = AT91C_SSC_RXEN | AT91C_SSC_TXEN;
+
+	// Sample at 2 Mbit/s, so TI tags are 16.2 vs. 14.9 clocks long
+	// 48/2 = 24 MHz clock must be divided by 12
+	AT91C_BASE_SSC->SSC_CMR = 12;
+
+	AT91C_BASE_SSC->SSC_RCMR = SSC_CLOCK_MODE_SELECT(0);
+	AT91C_BASE_SSC->SSC_RFMR = SSC_FRAME_MODE_BITS_IN_WORD(32) | AT91C_SSC_MSBF;
+	AT91C_BASE_SSC->SSC_TCMR = 0;
+	AT91C_BASE_SSC->SSC_TFMR = 0;
+
+	LED_D_ON();
+
+	// modulate antenna
+	HIGH(GPIO_SSC_DOUT);
+
+	// Charge TI tag for 50ms.
+	SpinDelay(50);
+
+	// stop modulating antenna and listen
+	LOW(GPIO_SSC_DOUT);
+
+	LED_D_OFF();
+
+	i = 0;
+	for(;;) {
+		if(AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+			BigBuf[i] = AT91C_BASE_SSC->SSC_RHR;	// store 32 bit values in buffer
+			i++; if(i >= TIBUFLEN) break;
+		}
+		WDT_HIT();
+	}
+
+	// return stolen pin to SSP
+	AT91C_BASE_PIOA->PIO_PDR = GPIO_SSC_DOUT;
+	AT91C_BASE_PIOA->PIO_ASR = GPIO_SSC_DIN | GPIO_SSC_DOUT;
+
+	char *dest = (char *)BigBuf;
+	n = TIBUFLEN*32;
+	// unpack buffer
+	for (i=TIBUFLEN-1; i>=0; i--) {
+		for (j=0; j<32; j++) {
+			if(BigBuf[i] & (1 << j)) {
+				dest[--n] = 1;
+			} else {
+				dest[--n] = -1;
+			}
+		}
+	}
+}
+
+// arguments: 64bit data split into 32bit idhi:idlo and optional 16bit crc
+// if crc provided, it will be written with the data verbatim (even if bogus)
+// if not provided a valid crc will be computed from the data and written.
+void WriteTItag(uint32_t idhi, uint32_t idlo, uint16_t crc)
+{
+	if(crc == 0) {
+	 	crc = update_crc16(crc, (idlo)&0xff);
+		crc = update_crc16(crc, (idlo>>8)&0xff);
+		crc = update_crc16(crc, (idlo>>16)&0xff);
+		crc = update_crc16(crc, (idlo>>24)&0xff);
+		crc = update_crc16(crc, (idhi)&0xff);
+		crc = update_crc16(crc, (idhi>>8)&0xff);
+		crc = update_crc16(crc, (idhi>>16)&0xff);
+		crc = update_crc16(crc, (idhi>>24)&0xff);
+	}
+	Dbprintf("Writing to tag: %x%08x, crc=%x",
+		(unsigned int) idhi, (unsigned int) idlo, crc);
+
+	// TI tags charge at 134.2Khz
+	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
+	// Place FPGA in passthrough mode, in this mode the CROSS_LO line
+	// connects to SSP_DIN and the SSP_DOUT logic level controls
+	// whether we're modulating the antenna (high)
+	// or listening to the antenna (low)
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU);
+	LED_A_ON();
+
+	// steal this pin from the SSP and use it to control the modulation
+	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
+	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+
+	// writing algorithm:
+	// a high bit consists of a field off for 1ms and field on for 1ms
+	// a low bit consists of a field off for 0.3ms and field on for 1.7ms
+	// initiate a charge time of 50ms (field on) then immediately start writing bits
+	// start by writing 0xBB (keyword) and 0xEB (password)
+	// then write 80 bits of data (or 64 bit data + 16 bit crc if you prefer)
+	// finally end with 0x0300 (write frame)
+	// all data is sent lsb firts
+	// finish with 15ms programming time
+
+	// modulate antenna
+	HIGH(GPIO_SSC_DOUT);
+	SpinDelay(50);	// charge time
+
+	WriteTIbyte(0xbb); // keyword
+	WriteTIbyte(0xeb); // password
+	WriteTIbyte( (idlo    )&0xff );
+	WriteTIbyte( (idlo>>8 )&0xff );
+	WriteTIbyte( (idlo>>16)&0xff );
+	WriteTIbyte( (idlo>>24)&0xff );
+	WriteTIbyte( (idhi    )&0xff );
+	WriteTIbyte( (idhi>>8 )&0xff );
+	WriteTIbyte( (idhi>>16)&0xff );
+	WriteTIbyte( (idhi>>24)&0xff ); // data hi to lo
+	WriteTIbyte( (crc     )&0xff ); // crc lo
+	WriteTIbyte( (crc>>8  )&0xff ); // crc hi
+	WriteTIbyte(0x00); // write frame lo
+	WriteTIbyte(0x03); // write frame hi
+	HIGH(GPIO_SSC_DOUT);
+	SpinDelay(50);	// programming time
+
+	LED_A_OFF();
+
+	// get TI tag data into the buffer
+	AcquireTiType();
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	DbpString("Now use tiread to check");
+}
+
+void SimulateTagLowFrequency(int period, int gap, int ledcontrol)
+{
+	int i;
+	uint8_t *tab = (uint8_t *)BigBuf;
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);
+
+	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT | GPIO_SSC_CLK;
+
+	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+	AT91C_BASE_PIOA->PIO_ODR = GPIO_SSC_CLK;
+
+#define SHORT_COIL()	LOW(GPIO_SSC_DOUT)
+#define OPEN_COIL()		HIGH(GPIO_SSC_DOUT)
+
+	i = 0;
+	for(;;) {
+		while(!(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK)) {
+			if(BUTTON_PRESS()) {
+				DbpString("Stopped");
+				return;
+			}
+			WDT_HIT();
+		}
+
+		if (ledcontrol)
+			LED_D_ON();
+
+		if(tab[i])
+			OPEN_COIL();
+		else
+			SHORT_COIL();
+
+		if (ledcontrol)
+			LED_D_OFF();
+
+		while(AT91C_BASE_PIOA->PIO_PDSR & GPIO_SSC_CLK) {
+			if(BUTTON_PRESS()) {
+				DbpString("Stopped");
+				return;
+			}
+			WDT_HIT();
+		}
+
+		i++;
+		if(i == period) {
+			i = 0;
+			if (gap) {
+				SHORT_COIL();
+				SpinDelayUs(gap);
+			}
+		}
+	}
+}
+
+/* Provides a framework for bidirectional LF tag communication
+ * Encoding is currently Hitag2, but the general idea can probably
+ * be transferred to other encodings.
+ *
+ * The new FPGA code will, for the LF simulator mode, give on SSC_FRAME
+ * (PA15) a thresholded version of the signal from the ADC. Setting the
+ * ADC path to the low frequency peak detection signal, will enable a
+ * somewhat reasonable receiver for modulation on the carrier signal
+ * that is generated by the reader. The signal is low when the reader
+ * field is switched off, and high when the reader field is active. Due
+ * to the way that the signal looks like, mostly only the rising edge is
+ * useful, your mileage may vary.
+ *
+ * Neat perk: PA15 can not only be used as a bit-banging GPIO, but is also
+ * TIOA1, which can be used as the capture input for timer 1. This should
+ * make it possible to measure the exact edge-to-edge time, without processor
+ * intervention.
+ *
+ * Arguments: divisor is the divisor to be sent to the FPGA (e.g. 95 for 125kHz)
+ * t0 is the carrier frequency cycle duration in terms of MCK (384 for 125kHz)
+ *
+ * The following defines are in carrier periods:
+ */
+#define HITAG_T_0_MIN 15 /* T[0] should be 18..22 */
+#define HITAG_T_1_MIN 24 /* T[1] should be 26..30 */
+#define HITAG_T_EOF   40 /* T_EOF should be > 36 */
+#define HITAG_T_WRESP 208 /* T_wresp should be 204..212 */
+
+static void hitag_handle_frame(int t0, int frame_len, char *frame);
+//#define DEBUG_RA_VALUES 1
+#define DEBUG_FRAME_CONTENTS 1
+void SimulateTagLowFrequencyBidir(int divisor, int t0)
+{
+#if DEBUG_RA_VALUES || DEBUG_FRAME_CONTENTS
+	int i = 0;
+#endif
+	char frame[10];
+	int frame_pos=0;
+
+	DbpString("Starting Hitag2 emulator, press button to end");
+	hitag2_init();
+
+	/* Set up simulator mode, frequency divisor which will drive the FPGA
+	 * and analog mux selection.
+	 */
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_SIMULATOR);
+	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
+	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+	RELAY_OFF();
+
+	/* Set up Timer 1:
+	 * Capture mode, timer source MCK/2 (TIMER_CLOCK1), TIOA is external trigger,
+	 * external trigger rising edge, load RA on rising edge of TIOA, load RB on rising
+	 * edge of TIOA. Assign PA15 to TIOA1 (peripheral B)
+	 */
+
+	AT91C_BASE_PMC->PMC_PCER = (1 << AT91C_ID_TC1);
+	AT91C_BASE_PIOA->PIO_BSR = GPIO_SSC_FRAME;
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_CLKDIS;
+	AT91C_BASE_TC1->TC_CMR =	AT91C_TC_CLKS_TIMER_DIV1_CLOCK |
+								AT91C_TC_ETRGEDG_RISING |
+								AT91C_TC_ABETRG |
+								AT91C_TC_LDRA_RISING |
+								AT91C_TC_LDRB_RISING;
+	AT91C_BASE_TC1->TC_CCR =	AT91C_TC_CLKEN |
+								AT91C_TC_SWTRG;
+
+	/* calculate the new value for the carrier period in terms of TC1 values */
+	t0 = t0/2;
+
+	int overflow = 0;
+	while(!BUTTON_PRESS()) {
+		WDT_HIT();
+		if(AT91C_BASE_TC1->TC_SR & AT91C_TC_LDRAS) {
+			int ra = AT91C_BASE_TC1->TC_RA;
+			if((ra > t0*HITAG_T_EOF) | overflow) ra = t0*HITAG_T_EOF+1;
+#if DEBUG_RA_VALUES
+			if(ra > 255 || overflow) ra = 255;
+			((char*)BigBuf)[i] = ra;
+			i = (i+1) % 8000;
+#endif
+
+			if(overflow || (ra > t0*HITAG_T_EOF) || (ra < t0*HITAG_T_0_MIN)) {
+				/* Ignore */
+			} else if(ra >= t0*HITAG_T_1_MIN ) {
+				/* '1' bit */
+				if(frame_pos < 8*sizeof(frame)) {
+					frame[frame_pos / 8] |= 1<<( 7-(frame_pos%8) );
+					frame_pos++;
+				}
+			} else if(ra >= t0*HITAG_T_0_MIN) {
+				/* '0' bit */
+				if(frame_pos < 8*sizeof(frame)) {
+					frame[frame_pos / 8] |= 0<<( 7-(frame_pos%8) );
+					frame_pos++;
+				}
+			}
+
+			overflow = 0;
+			LED_D_ON();
+		} else {
+			if(AT91C_BASE_TC1->TC_CV > t0*HITAG_T_EOF) {
+				/* Minor nuisance: In Capture mode, the timer can not be
+				 * stopped by a Compare C. There's no way to stop the clock
+				 * in software, so we'll just have to note the fact that an
+				 * overflow happened and the next loaded timer value might
+				 * have wrapped. Also, this marks the end of frame, and the
+				 * still running counter can be used to determine the correct
+				 * time for the start of the reply.
+				 */
+				overflow = 1;
+
+				if(frame_pos > 0) {
+					/* Have a frame, do something with it */
+#if DEBUG_FRAME_CONTENTS
+					((char*)BigBuf)[i++] = frame_pos;
+					memcpy( ((char*)BigBuf)+i, frame, 7);
+					i+=7;
+					i = i % sizeof(BigBuf);
+#endif
+					hitag_handle_frame(t0, frame_pos, frame);
+					memset(frame, 0, sizeof(frame));
+				}
+				frame_pos = 0;
+
+			}
+			LED_D_OFF();
+		}
+	}
+	DbpString("All done");
+}
+
+static void hitag_send_bit(int t0, int bit) {
+	if(bit == 1) {
+		/* Manchester: Loaded, then unloaded */
+		LED_A_ON();
+		SHORT_COIL();
+		while(AT91C_BASE_TC1->TC_CV < t0*15);
+		OPEN_COIL();
+		while(AT91C_BASE_TC1->TC_CV < t0*31);
+		LED_A_OFF();
+	} else if(bit == 0) {
+		/* Manchester: Unloaded, then loaded */
+		LED_B_ON();
+		OPEN_COIL();
+		while(AT91C_BASE_TC1->TC_CV < t0*15);
+		SHORT_COIL();
+		while(AT91C_BASE_TC1->TC_CV < t0*31);
+		LED_B_OFF();
+	}
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; /* Reset clock for the next bit */
+
+}
+static void hitag_send_frame(int t0, int frame_len, const char const * frame, int fdt)
+{
+	OPEN_COIL();
+	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
+
+	/* Wait for HITAG_T_WRESP carrier periods after the last reader bit,
+	 * not that since the clock counts since the rising edge, but T_wresp is
+	 * with respect to the falling edge, we need to wait actually (T_wresp - T_g)
+	 * periods. The gap time T_g varies (4..10).
+	 */
+	while(AT91C_BASE_TC1->TC_CV < t0*(fdt-8));
+
+	int saved_cmr = AT91C_BASE_TC1->TC_CMR;
+	AT91C_BASE_TC1->TC_CMR &= ~AT91C_TC_ETRGEDG; /* Disable external trigger for the clock */
+	AT91C_BASE_TC1->TC_CCR = AT91C_TC_SWTRG; /* Reset the clock and use it for response timing */
+
+	int i;
+	for(i=0; i<5; i++)
+		hitag_send_bit(t0, 1); /* Start of frame */
+
+	for(i=0; i<frame_len; i++) {
+		hitag_send_bit(t0, !!(frame[i/ 8] & (1<<( 7-(i%8) ))) );
+	}
+
+	OPEN_COIL();
+	AT91C_BASE_TC1->TC_CMR = saved_cmr;
+}
+
+/* Callback structure to cleanly separate tag emulation code from the radio layer. */
+static int hitag_cb(const char* response_data, const int response_length, const int fdt, void *cb_cookie)
+{
+	hitag_send_frame(*(int*)cb_cookie, response_length, response_data, fdt);
+	return 0;
+}
+/* Frame length in bits, frame contents in MSBit first format */
+static void hitag_handle_frame(int t0, int frame_len, char *frame)
+{
+	hitag2_handle_command(frame, frame_len, hitag_cb, &t0);
+}
+
+// compose fc/8 fc/10 waveform
+static void fc(int c, int *n) {
+	uint8_t *dest = (uint8_t *)BigBuf;
+	int idx;
+
+	// for when we want an fc8 pattern every 4 logical bits
+	if(c==0) {
+		dest[((*n)++)]=1;
+		dest[((*n)++)]=1;
+		dest[((*n)++)]=0;
+		dest[((*n)++)]=0;
+		dest[((*n)++)]=0;
+		dest[((*n)++)]=0;
+		dest[((*n)++)]=0;
+		dest[((*n)++)]=0;
+	}
+	//	an fc/8  encoded bit is a bit pattern of  11000000  x6 = 48 samples
+	if(c==8) {
+		for (idx=0; idx<6; idx++) {
+			dest[((*n)++)]=1;
+			dest[((*n)++)]=1;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+		}
+	}
+
+	//	an fc/10 encoded bit is a bit pattern of 1110000000 x5 = 50 samples
+	if(c==10) {
+		for (idx=0; idx<5; idx++) {
+			dest[((*n)++)]=1;
+			dest[((*n)++)]=1;
+			dest[((*n)++)]=1;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+			dest[((*n)++)]=0;
+		}
+	}
+}
+
+// prepare a waveform pattern in the buffer based on the ID given then
+// simulate a HID tag until the button is pressed
+void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
+{
+	int n=0, i=0;
+	/*
+	 HID tag bitstream format
+	 The tag contains a 44bit unique code. This is sent out MSB first in sets of 4 bits
+	 A 1 bit is represented as 6 fc8 and 5 fc10 patterns
+	 A 0 bit is represented as 5 fc10 and 6 fc8 patterns
+	 A fc8 is inserted before every 4 bits
+	 A special start of frame pattern is used consisting a0b0 where a and b are neither 0
+	 nor 1 bits, they are special patterns (a = set of 12 fc8 and b = set of 10 fc10)
+	*/
+
+	if (hi>0xFFF) {
+		DbpString("Tags can only have 44 bits.");
+		return;
+	}
+	fc(0,&n);
+	// special start of frame marker containing invalid bit sequences
+	fc(8,  &n);	fc(8,  &n);	// invalid
+	fc(8,  &n);	fc(10, &n); // logical 0
+	fc(10, &n);	fc(10, &n); // invalid
+	fc(8,  &n);	fc(10, &n); // logical 0
+
+	WDT_HIT();
+	// manchester encode bits 43 to 32
+	for (i=11; i>=0; i--) {
+		if ((i%4)==3) fc(0,&n);
+		if ((hi>>i)&1) {
+			fc(10, &n);	fc(8,  &n);		// low-high transition
+		} else {
+			fc(8,  &n);	fc(10, &n);		// high-low transition
+		}
+	}
+
+	WDT_HIT();
+	// manchester encode bits 31 to 0
+	for (i=31; i>=0; i--) {
+		if ((i%4)==3) fc(0,&n);
+		if ((lo>>i)&1) {
+			fc(10, &n);	fc(8,  &n);		// low-high transition
+		} else {
+			fc(8,  &n);	fc(10, &n);		// high-low transition
+		}
+	}
+
+	if (ledcontrol)
+		LED_A_ON();
+	SimulateTagLowFrequency(n, 0, ledcontrol);
+
+	if (ledcontrol)
+		LED_A_OFF();
+}
+
+
+// loop to capture raw HID waveform then FSK demodulate the TAG ID from it
+void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
+{
+	uint8_t *dest = (uint8_t *)BigBuf;
+	int m=0, n=0, i=0, idx=0, found=0, lastval=0;
+	uint32_t hi=0, lo=0;
+
+	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+
+	// Connect the A/D to the peak-detected low-frequency path.
+	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+
+	// Give it a bit of time for the resonant antenna to settle.
+	SpinDelay(50);
+
+	// Now set up the SSC to get the ADC samples that are now streaming at us.
+	FpgaSetupSsc();
+
+	for(;;) {
+		WDT_HIT();
+		if (ledcontrol)
+			LED_A_ON();
+		if(BUTTON_PRESS()) {
+			DbpString("Stopped");
+			if (ledcontrol)
+				LED_A_OFF();
+			return;
+		}
+
+		i = 0;
+		m = sizeof(BigBuf);
+		memset(dest,128,m);
+		for(;;) {
+			if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_TXRDY)) {
+				AT91C_BASE_SSC->SSC_THR = 0x43;
+				if (ledcontrol)
+					LED_D_ON();
+			}
+			if(AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
+				dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+				// we don't care about actual value, only if it's more or less than a
+				// threshold essentially we capture zero crossings for later analysis
+				if(dest[i] < 127) dest[i] = 0; else dest[i] = 1;
+				i++;
+				if (ledcontrol)
+					LED_D_OFF();
+				if(i >= m) {
+					break;
+				}
+			}
+		}
+
+		// FSK demodulator
+
+		// sync to first lo-hi transition
+		for( idx=1; idx<m; idx++) {
+			if (dest[idx-1]<dest[idx])
+				lastval=idx;
+				break;
+		}
+		WDT_HIT();
+
+		// count cycles between consecutive lo-hi transitions, there should be either 8 (fc/8)
+		// or 10 (fc/10) cycles but in practice due to noise etc we may end up with with anywhere
+		// between 7 to 11 cycles so fuzz it by treat anything <9 as 8 and anything else as 10
+		for( i=0; idx<m; idx++) {
+			if (dest[idx-1]<dest[idx]) {
+				dest[i]=idx-lastval;
+				if (dest[i] <= 8) {
+						dest[i]=1;
+				} else {
+						dest[i]=0;
+				}
+
+				lastval=idx;
+				i++;
+			}
+		}
+		m=i;
+		WDT_HIT();
+
+		// we now have a set of cycle counts, loop over previous results and aggregate data into bit patterns
+		lastval=dest[0];
+		idx=0;
+		i=0;
+		n=0;
+		for( idx=0; idx<m; idx++) {
+			if (dest[idx]==lastval) {
+				n++;
+			} else {
+				// a bit time is five fc/10 or six fc/8 cycles so figure out how many bits a pattern width represents,
+				// an extra fc/8 pattern preceeds every 4 bits (about 200 cycles) just to complicate things but it gets
+				// swallowed up by rounding
+				// expected results are 1 or 2 bits, any more and it's an invalid manchester encoding
+				// special start of frame markers use invalid manchester states (no transitions) by using sequences
+				// like 111000
+				if (dest[idx-1]) {
+					n=(n+1)/6;			// fc/8 in sets of 6
+				} else {
+					n=(n+1)/5;			// fc/10 in sets of 5
+				}
+				switch (n) {			// stuff appropriate bits in buffer
+					case 0:
+					case 1:	// one bit
+						dest[i++]=dest[idx-1];
+						break;
+					case 2: // two bits
+						dest[i++]=dest[idx-1];
+						dest[i++]=dest[idx-1];
+						break;
+					case 3: // 3 bit start of frame markers
+						dest[i++]=dest[idx-1];
+						dest[i++]=dest[idx-1];
+						dest[i++]=dest[idx-1];
+						break;
+					// When a logic 0 is immediately followed by the start of the next transmisson
+					// (special pattern) a pattern of 4 bit duration lengths is created.
+					case 4:
+						dest[i++]=dest[idx-1];
+						dest[i++]=dest[idx-1];
+						dest[i++]=dest[idx-1];
+						dest[i++]=dest[idx-1];
+						break;
+					default:	// this shouldn't happen, don't stuff any bits
+						break;
+				}
+				n=0;
+				lastval=dest[idx];
+			}
+		}
+		m=i;
+		WDT_HIT();
+
+		// final loop, go over previously decoded manchester data and decode into usable tag ID
+		// 111000 bit pattern represent start of frame, 01 pattern represents a 1 and 10 represents a 0
+		for( idx=0; idx<m-6; idx++) {
+			// search for a start of frame marker
+			if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
+			{
+				found=1;
+				idx+=6;
+				if (found && (hi|lo)) {
+					Dbprintf("TAG ID: %x%08x (%d)",
+						(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
+					/* if we're only looking for one tag */
+					if (findone)
+					{
+						*high = hi;
+						*low = lo;
+						return;
+					}
+					hi=0;
+					lo=0;
+					found=0;
+				}
+			}
+			if (found) {
+				if (dest[idx] && (!dest[idx+1]) ) {
+					hi=(hi<<1)|(lo>>31);
+					lo=(lo<<1)|0;
+				} else if ( (!dest[idx]) && dest[idx+1]) {
+					hi=(hi<<1)|(lo>>31);
+					lo=(lo<<1)|1;
+				} else {
+					found=0;
+					hi=0;
+					lo=0;
+				}
+				idx++;
+			}
+			if ( dest[idx] && dest[idx+1] && dest[idx+2] && (!dest[idx+3]) && (!dest[idx+4]) && (!dest[idx+5]) )
+			{
+				found=1;
+				idx+=6;
+				if (found && (hi|lo)) {
+					Dbprintf("TAG ID: %x%08x (%d)",
+						(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
+					/* if we're only looking for one tag */
+					if (findone)
+					{
+						*high = hi;
+						*low = lo;
+						return;
+					}
+					hi=0;
+					lo=0;
+					found=0;
+				}
+			}
+		}
+		WDT_HIT();
+	}
+}
+
+/*------------------------------
+ * T5555/T5557/T5567 routines
+ *------------------------------
+ */
+
+/* T55x7 configuration register definitions */
+#define T55x7_POR_DELAY			0x00000001
+#define T55x7_ST_TERMINATOR		0x00000008
+#define T55x7_PWD			0x00000010
+#define T55x7_MAXBLOCK_SHIFT		5
+#define T55x7_AOR			0x00000200
+#define T55x7_PSKCF_RF_2		0
+#define T55x7_PSKCF_RF_4		0x00000400
+#define T55x7_PSKCF_RF_8		0x00000800
+#define T55x7_MODULATION_DIRECT		0
+#define T55x7_MODULATION_PSK1		0x00001000
+#define T55x7_MODULATION_PSK2		0x00002000
+#define T55x7_MODULATION_PSK3		0x00003000
+#define T55x7_MODULATION_FSK1		0x00004000
+#define T55x7_MODULATION_FSK2		0x00005000
+#define T55x7_MODULATION_FSK1a		0x00006000
+#define T55x7_MODULATION_FSK2a		0x00007000
+#define T55x7_MODULATION_MANCHESTER	0x00008000
+#define T55x7_MODULATION_BIPHASE	0x00010000
+#define T55x7_BITRATE_RF_8		0
+#define T55x7_BITRATE_RF_16		0x00040000
+#define T55x7_BITRATE_RF_32		0x00080000
+#define T55x7_BITRATE_RF_40		0x000C0000
+#define T55x7_BITRATE_RF_50		0x00100000
+#define T55x7_BITRATE_RF_64		0x00140000
+#define T55x7_BITRATE_RF_100		0x00180000
+#define T55x7_BITRATE_RF_128		0x001C0000
+
+/* T5555 (Q5) configuration register definitions */
+#define T5555_ST_TERMINATOR		0x00000001
+#define T5555_MAXBLOCK_SHIFT		0x00000001
+#define T5555_MODULATION_MANCHESTER	0
+#define T5555_MODULATION_PSK1		0x00000010
+#define T5555_MODULATION_PSK2		0x00000020
+#define T5555_MODULATION_PSK3		0x00000030
+#define T5555_MODULATION_FSK1		0x00000040
+#define T5555_MODULATION_FSK2		0x00000050
+#define T5555_MODULATION_BIPHASE	0x00000060
+#define T5555_MODULATION_DIRECT		0x00000070
+#define T5555_INVERT_OUTPUT		0x00000080
+#define T5555_PSK_RF_2			0
+#define T5555_PSK_RF_4			0x00000100
+#define T5555_PSK_RF_8			0x00000200
+#define T5555_USE_PWD			0x00000400
+#define T5555_USE_AOR			0x00000800
+#define T5555_BITRATE_SHIFT		12
+#define T5555_FAST_WRITE		0x00004000
+#define T5555_PAGE_SELECT		0x00008000
+
+/*
+ * Relevant times in microsecond
+ * To compensate antenna falling times shorten the write times
+ * and enlarge the gap ones.
+ */
+#define START_GAP 250
+#define WRITE_GAP 160
+#define WRITE_0   144 // 192
+#define WRITE_1   400 // 432 for T55x7; 448 for E5550
+
+// Write one bit to card
+void T55xxWriteBit(int bit)
+{
+	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+	if (bit == 0)
+		SpinDelayUs(WRITE_0);
+	else
+		SpinDelayUs(WRITE_1);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	SpinDelayUs(WRITE_GAP);
+}
+
+// Write one card block in page 0, no lock
+void T55xxWriteBlock(int Data, int Block)
+{
+	unsigned int i;
+
+	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+
+	// Give it a bit of time for the resonant antenna to settle.
+	// And for the tag to fully power up
+	SpinDelay(150);
+
+	// Now start writting
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	SpinDelayUs(START_GAP);
+
+	// Opcode
+	T55xxWriteBit(1);
+	T55xxWriteBit(0); //Page 0
+	// Lock bit
+	T55xxWriteBit(0);
+
+	// Data
+	for (i = 0x80000000; i != 0; i >>= 1)
+		T55xxWriteBit(Data & i);
+
+	// Page
+	for (i = 0x04; i != 0; i >>= 1)
+		T55xxWriteBit(Block & i);
+
+	// Now perform write (nominal is 5.6 ms for T55x7 and 18ms for E5550,
+	// so wait a little more)
+	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER);
+	SpinDelay(20);
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+}
+
+// Copy HID id to card and setup block 0 config
+void CopyHIDtoT55x7(int hi, int lo)
+{
+	int data1, data2, data3;
+
+	// Ensure no more than 44 bits supplied
+	if (hi>0xFFF) {
+		DbpString("Tags can only have 44 bits.");
+		return;
+	}
+
+	// Build the 3 data blocks for supplied 44bit ID
+	data1 = 0x1D000000; // load preamble
+
+	for (int i=0;i<12;i++) {
+		if (hi & (1<<(11-i)))
+			data1 |= (1<<(((11-i)*2)+1)); // 1 -> 10
+		else
+			data1 |= (1<<((11-i)*2)); // 0 -> 01
+	}
+
+	data2 = 0;
+	for (int i=0;i<16;i++) {
+		if (lo & (1<<(31-i)))
+			data2 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+		else
+			data2 |= (1<<((15-i)*2)); // 0 -> 01
+	}
+
+	data3 = 0;
+	for (int i=0;i<16;i++) {
+		if (lo & (1<<(15-i)))
+			data3 |= (1<<(((15-i)*2)+1)); // 1 -> 10
+		else
+			data3 |= (1<<((15-i)*2)); // 0 -> 01
+	}
+
+	// Program the 3 data blocks for supplied 44bit ID
+	// and the block 0 for HID format
+	T55xxWriteBlock(data1,1);
+	T55xxWriteBlock(data2,2);
+	T55xxWriteBlock(data3,3);
+
+	// Config for HID (RF/50, FSK2a, Maxblock=3)
+	T55xxWriteBlock(T55x7_BITRATE_RF_50    |
+			T55x7_MODULATION_FSK2a |
+			3 << T55x7_MAXBLOCK_SHIFT,
+			0);
+
+	DbpString("DONE!");
+}
+
+// Define 9bit header for EM410x tags
+#define EM410X_HEADER		0x1FF
+#define EM410X_ID_LENGTH	40
+
+void WriteEM410x(uint32_t card, uint32_t id_hi, uint32_t id_lo)
+{
+	int i, id_bit;
+	uint64_t id = EM410X_HEADER;
+	uint64_t rev_id = 0;	// reversed ID
+	int c_parity[4];	// column parity
+	int r_parity = 0;	// row parity
+
+	// Reverse ID bits given as parameter (for simpler operations)
+	for (i = 0; i < EM410X_ID_LENGTH; ++i) {
+		if (i < 32) {
+			rev_id = (rev_id << 1) | (id_lo & 1);
+			id_lo >>= 1;
+		} else {
+			rev_id = (rev_id << 1) | (id_hi & 1);
+			id_hi >>= 1;
+		}
+	}
+
+	for (i = 0; i < EM410X_ID_LENGTH; ++i) {
+		id_bit = rev_id & 1;
+
+		if (i % 4 == 0) {
+			// Don't write row parity bit at start of parsing
+			if (i)
+				id = (id << 1) | r_parity;
+			// Start counting parity for new row
+			r_parity = id_bit;
+		} else {
+			// Count row parity
+			r_parity ^= id_bit;
+		}
+
+		// First elements in column?
+		if (i < 4)
+			// Fill out first elements
+			c_parity[i] = id_bit;
+		else
+			// Count column parity
+			c_parity[i % 4] ^= id_bit;
+
+		// Insert ID bit
+		id = (id << 1) | id_bit;
+		rev_id >>= 1;
+	}
+
+	// Insert parity bit of last row
+	id = (id << 1) | r_parity;
+
+	// Fill out column parity at the end of tag
+	for (i = 0; i < 4; ++i)
+		id = (id << 1) | c_parity[i];
+
+	// Add stop bit
+	id <<= 1;
+
+	Dbprintf("Started writing %s tag ...", card ? "T55x7":"T5555");
+	LED_D_ON();
+
+	// Write EM410x ID
+	T55xxWriteBlock((uint32_t)(id >> 32), 1);
+	T55xxWriteBlock((uint32_t)id, 2);
+
+	// Config for EM410x (RF/64, Manchester, Maxblock=2)
+	if (card)
+		// Writing configuration for T55x7 tag
+		T55xxWriteBlock(T55x7_BITRATE_RF_64	    |
+				T55x7_MODULATION_MANCHESTER |
+				2 << T55x7_MAXBLOCK_SHIFT,
+				0);
+	else
+		// Writing configuration for T5555(Q5) tag
+		T55xxWriteBlock(0x1F << T5555_BITRATE_SHIFT |
+				T5555_MODULATION_MANCHESTER   |
+				2 << T5555_MAXBLOCK_SHIFT,
+				0);
+
+	LED_D_OFF();
+	Dbprintf("Tag %s written with 0x%08x%08x\n", card ? "T55x7":"T5555",
+					(uint32_t)(id >> 32), (uint32_t)id);
+}
+
+// Clone Indala 64-bit tag by UID to T55x7
+void CopyIndala64toT55x7(int hi, int lo)
+{
+
+	//Program the 2 data blocks for supplied 64bit UID
+	// and the block 0 for Indala64 format
+	T55xxWriteBlock(hi,1);
+	T55xxWriteBlock(lo,2);
+	//Config for Indala (RF/32;PSK1 with RF/2;Maxblock=2)
+	T55xxWriteBlock(T55x7_BITRATE_RF_32    |
+			T55x7_MODULATION_PSK1 |
+			2 << T55x7_MAXBLOCK_SHIFT,
+			0);
+	//Alternative config for Indala (Extended mode;RF/32;PSK1 with RF/2;Maxblock=2;Inverse data)
+//	T5567WriteBlock(0x603E1042,0);
+
+	DbpString("DONE!");
+
+}	
+
+void CopyIndala224toT55x7(int uid1, int uid2, int uid3, int uid4, int uid5, int uid6, int uid7)
+{
+
+	//Program the 7 data blocks for supplied 224bit UID
+	// and the block 0 for Indala224 format
+	T55xxWriteBlock(uid1,1);
+	T55xxWriteBlock(uid2,2);
+	T55xxWriteBlock(uid3,3);
+	T55xxWriteBlock(uid4,4);
+	T55xxWriteBlock(uid5,5);
+	T55xxWriteBlock(uid6,6);
+	T55xxWriteBlock(uid7,7);
+	//Config for Indala (RF/32;PSK1 with RF/2;Maxblock=7)
+	T55xxWriteBlock(T55x7_BITRATE_RF_32    |
+			T55x7_MODULATION_PSK1 |
+			7 << T55x7_MAXBLOCK_SHIFT,
+			0);
+	//Alternative config for Indala (Extended mode;RF/32;PSK1 with RF/2;Maxblock=7;Inverse data)
+//	T5567WriteBlock(0x603E10E2,0);
+
+	DbpString("DONE!");
+
+}