X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/08b7cd17a5e9084d8baeed4c0afa4c7933e24fe6..refs/pull/862/head:/armsrc/lfops.c?ds=inline

diff --git a/armsrc/lfops.c b/armsrc/lfops.c
index 641c02e8..12f9de08 100644
--- a/armsrc/lfops.c
+++ b/armsrc/lfops.c
@@ -4,7 +4,7 @@
 // the license.
 //-----------------------------------------------------------------------------
 // Miscellaneous routines for low frequency tag operations.
-// Tags supported here so far are Texas Instruments (TI), HID
+// Tags supported here so far are Texas Instruments (TI), HID, EM4x05, EM410x
 // Also routines for raw mode reading/simulating of LF waveform
 //-----------------------------------------------------------------------------
 
@@ -18,6 +18,7 @@
 #include "lfsampling.h"
 #include "protocols.h"
 #include "usb_cdc.h" // for usb_poll_validate_length
+#include "fpgaloader.h"
 
 /**
  * Function to do a modulation and then get samples.
@@ -28,51 +29,103 @@
  */
 void ModThenAcquireRawAdcSamples125k(uint32_t delay_off, uint32_t period_0, uint32_t period_1, uint8_t *command)
 {
+	// start timer
+	StartTicks();
 
-	int divisor_used = 95; // 125 KHz
-	// see if 'h' was specified
-
-	if (command[strlen((char *) command) - 1] == 'h')
-		divisor_used = 88; // 134.8 KHz
+	// use lf config settings
+	sample_config *sc = getSamplingConfig();
 
-	sample_config sc = { 0,0,1, divisor_used, 0};
-	setSamplingConfig(&sc);
-	//clear read buffer
-	BigBuf_Clear_keep_EM();
-
-	/* Make sure the tag is reset */
+	// Make sure the tag is reset
 	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	SpinDelay(2500);
+	WaitMS(2500);
 
-	LFSetupFPGAForADC(sc.divisor, 1);
+	// clear read buffer (after fpga bitstream loaded...)
+	BigBuf_Clear_keep_EM();
 
-	// And a little more time for the tag to fully power up
-	SpinDelay(2000);
+	// power on
+	LFSetupFPGAForADC(sc->divisor, 1);
 
+	// And a little more time for the tag to fully power up
+	WaitMS(2000);
+	// if delay_off = 0 then just bitbang 1 = antenna on 0 = off for respective periods.
+	bool bitbang = delay_off == 0;
 	// now modulate the reader field
-	while(*command != '\0' && *command != ' ') {
+
+	if (bitbang) {
+		// HACK it appears the loop and if statements take up about 7us so adjust waits accordingly...
+		uint8_t hack_cnt = 7;
+		if (period_0 < hack_cnt || period_1 < hack_cnt) {
+			DbpString("Warning periods cannot be less than 7us in bit bang mode");
+			FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+			LED_D_OFF();
+			return;
+		}
+
+		// hack2 needed---  it appears to take about 8-16us to turn the antenna back on 
+		// leading to ~ 1 to 2 125khz samples extra in every off period 
+		// so we should test for last 0 before next 1 and reduce period_0 by this extra amount...
+		// but is this time different for every antenna or other hw builds???  more testing needed
+
+		// prime cmd_len to save time comparing strings while modulating
+		int cmd_len = 0;
+		while(command[cmd_len] != '\0' && command[cmd_len] != ' ')
+			cmd_len++;
+
+		int counter = 0;
+		bool off = false;
+		for (counter = 0; counter < cmd_len; counter++) {
+			// if cmd = 0 then turn field off
+			if (command[counter] == '0') {
+				// if field already off leave alone (affects timing otherwise)
+				if (off == false) {
+					FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+					LED_D_OFF();
+					off = true;
+				}
+				// note we appear to take about 7us to switch over (or run the if statements/loop...)
+				WaitUS(period_0-hack_cnt);
+			// else if cmd = 1 then turn field on
+			} else {
+				// if field already on leave alone (affects timing otherwise)
+				if (off) {
+					FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+					LED_D_ON();
+					off = false;
+				}
+				// note we appear to take about 7us to switch over (or run the if statements/loop...)
+				WaitUS(period_1-hack_cnt);
+			}
+		}
+	} else { // old mode of cmd read using delay as off period
+		while(*command != '\0' && *command != ' ') {
+			FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+			LED_D_OFF();
+			WaitUS(delay_off);
+			FpgaSendCommand(FPGA_CMD_SET_DIVISOR, sc->divisor);
+			FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
+			LED_D_ON();
+			if(*(command++) == '0') {
+				WaitUS(period_0);
+			} else {
+				WaitUS(period_1);
+			}
+		}
 		FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
 		LED_D_OFF();
-		SpinDelayUs(delay_off);
-		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, sc.divisor);
-
-		FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
-		LED_D_ON();
-		if(*(command++) == '0')
-			SpinDelayUs(period_0);
-		else
-			SpinDelayUs(period_1);
+		WaitUS(delay_off);
+		FpgaSendCommand(FPGA_CMD_SET_DIVISOR, sc->divisor);
 	}
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	LED_D_OFF();
-	SpinDelayUs(delay_off);
-	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, sc.divisor);
 
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 
 	// now do the read
 	DoAcquisition_config(false, 0);
+
+	// Turn off antenna
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
+	// tell client we are done
+	cmd_send(CMD_ACK,0,0,0,0,0);
 }
 
 /* blank r/w tag data stream
@@ -516,7 +569,7 @@ static void fcAll(uint8_t fc, int *n, uint8_t clock, uint16_t *modCnt)
 	uint8_t wavesPerClock = clock/fc;
 	uint8_t mod = clock % fc;    //modifier
 	uint8_t modAdj = fc/mod;     //how often to apply modifier
-	bool modAdjOk = !(fc % mod); //if (fc % mod==0) modAdjOk=TRUE;
+	bool modAdjOk = !(fc % mod); //if (fc % mod==0) modAdjOk=true;
 	// loop through clock - step field clock
 	for (uint8_t idx=0; idx < wavesPerClock; idx++){
 		// put 1/2 FC length 1's and 1/2 0's per field clock wave (to create the wave)
@@ -541,7 +594,7 @@ static void fcAll(uint8_t fc, int *n, uint8_t clock, uint16_t *modCnt)
 
 // 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)
+void CmdHIDsimTAG(int hi2, int hi, int lo, int ledcontrol)
 {
 	int n=0, i=0;
 	/*
@@ -554,8 +607,8 @@ void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
 	 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. - USE lf simfsk for larger tags");
+	if (hi2>0x0FFFFFFF) {
+		DbpString("Tags can only have 44 or 84 bits. - USE lf simfsk for larger tags");
 		return;
 	}
 	// set LF so we don't kill the bigbuf we are setting with simulation data.
@@ -569,13 +622,35 @@ void CmdHIDsimTAG(int hi, int lo, int ledcontrol)
 	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
+	if (hi2 > 0 || hi > 0xFFF){
+		// manchester encode bits 91 to 64 (91-84 are part of the header)
+		for (i=27; i>=0; i--) {
+			if ((i%4)==3) fc(0,&n);
+			if ((hi2>>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 63 to 32
+		for (i=31; 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
+			}
+		}
+	} else {
+		// 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
+			}
 		}
 	}
 
@@ -768,9 +843,9 @@ void CmdPSKsimTag(uint16_t arg1, uint16_t arg2, size_t size, uint8_t *BitStream)
 
 	for (i=0; i<size; i++){
 		if (BitStream[i] == curPhase){
-			pskSimBit(carrier, &n, clk, &curPhase, FALSE);
+			pskSimBit(carrier, &n, clk, &curPhase, false);
 		} else {
-			pskSimBit(carrier, &n, clk, &curPhase, TRUE);
+			pskSimBit(carrier, &n, clk, &curPhase, true);
 		}
 	}
 	Dbprintf("Simulating with Carrier: %d, clk: %d, invert: %d, n: %d",carrier, clk, invert, n);
@@ -787,7 +862,7 @@ void CmdPSKsimTag(uint16_t arg1, uint16_t arg2, size_t size, uint8_t *BitStream)
 }
 
 // loop to get raw HID waveform then FSK demodulate the TAG ID from it
-void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
+void CmdHIDdemodFSK(int findone, int *high2, int *high, int *low, int ledcontrol)
 {
 	uint8_t *dest = BigBuf_get_addr();
 	//const size_t sizeOfBigBuff = BigBuf_max_traceLen();
@@ -802,7 +877,6 @@ void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
 	BigBuf_Clear_keep_EM();
 
 	while(!BUTTON_PRESS() && !usb_poll_validate_length()) {
-
 		WDT_HIT();
 		if (ledcontrol) LED_A_ON();
 
@@ -813,60 +887,70 @@ void CmdHIDdemodFSK(int findone, int *high, int *low, int ledcontrol)
 		idx = HIDdemodFSK(dest, &size, &hi2, &hi, &lo, &dummyIdx);
 		
 		if (idx>0 && lo>0 && (size==96 || size==192)){
+			uint8_t bitlen = 0;
+			uint32_t fc = 0;
+			uint32_t cardnum = 0;
+			bool decoded = false;
+
 			// go over previously decoded manchester data and decode into usable tag ID
-			if (hi2 != 0){ //extra large HID tags  88/192 bits
-				Dbprintf("TAG ID: %x%08x%08x (%d)",
-				  (unsigned int) hi2, (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
-			}else {  //standard HID tags 44/96 bits
-				//Dbprintf("TAG ID: %x%08x (%d)",(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF); //old print cmd
-				uint8_t bitlen = 0;
-				uint32_t fc = 0;
-				uint32_t cardnum = 0;
-				if (((hi>>5)&1) == 1){//if bit 38 is set then < 37 bit format is used
-					uint32_t lo2=0;
-					lo2=(((hi & 31) << 12) | (lo>>20)); //get bits 21-37 to check for format len bit
-					uint8_t idx3 = 1;
-					while(lo2 > 1){ //find last bit set to 1 (format len bit)
-						lo2=lo2 >> 1;
-						idx3++;
-					}
-					bitlen = idx3+19;
-					fc =0;
-					cardnum=0;
-					if(bitlen == 26){
-						cardnum = (lo>>1)&0xFFFF;
-						fc = (lo>>17)&0xFF;
-					}
-					if(bitlen == 37){
-						cardnum = (lo>>1)&0x7FFFF;
-						fc = ((hi&0xF)<<12)|(lo>>20);
-					}
-					if(bitlen == 34){
-						cardnum = (lo>>1)&0xFFFF;
-						fc= ((hi&1)<<15)|(lo>>17);
-					}
-					if(bitlen == 35){
-						cardnum = (lo>>1)&0xFFFFF;
-						fc = ((hi&1)<<11)|(lo>>21);
-					}
+			if ((hi2 & 0x000FFFF) != 0){ //extra large HID tags  88/192 bits
+				uint32_t bp = hi2 & 0x000FFFFF;
+				bitlen = 63;
+				while (bp > 0) {
+					bp = bp >> 1;
+					bitlen++;
 				}
-				else { //if bit 38 is not set then 37 bit format is used
-					bitlen= 37;
-					fc =0;
-					cardnum=0;
-					if(bitlen==37){
-						cardnum = (lo>>1)&0x7FFFF;
-						fc = ((hi&0xF)<<12)|(lo>>20);
-					}
+			} else if ((hi >> 6) > 0) {
+				uint32_t bp = hi;
+				bitlen = 31;
+				while (bp > 0) {
+					bp = bp >> 1;
+					bitlen++;
 				}
-				//Dbprintf("TAG ID: %x%08x (%d)",
-				// (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
-				Dbprintf("TAG ID: %x%08x (%d) - Format Len: %dbit - FC: %d - Card: %d",
-						 (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF,
-						 (unsigned int) bitlen, (unsigned int) fc, (unsigned int) cardnum);
+			} else if (((hi >> 5) & 1) == 0) {
+				bitlen = 37;
+			} else if ((hi & 0x0000001F) > 0 ) {
+				uint32_t bp = (hi & 0x0000001F);
+				bitlen = 31;
+				while (bp > 0) {
+					bp = bp >> 1;
+					bitlen++;
+				}
+			} else {
+				uint32_t bp = lo;
+				bitlen = 0;
+				while (bp > 0) {
+					bp = bp >> 1;
+					bitlen++;
+				}
+			}
+			switch (bitlen){
+				case 26:
+					cardnum = (lo>>1)&0xFFFF;
+					fc = (lo>>17)&0xFF;
+					decoded = true;
+					break;
+				case 35:
+					cardnum = (lo>>1)&0xFFFFF;
+					fc = ((hi&1)<<11)|(lo>>21);
+					decoded = true;
+					break;
 			}
+				
+			if (hi2 != 0) //extra large HID tags  88/192 bits
+				Dbprintf("TAG ID: %x%08x%08x (%d)",
+					(unsigned int) hi2, (unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
+			else 
+				Dbprintf("TAG ID: %x%08x (%d)",
+					(unsigned int) hi, (unsigned int) lo, (unsigned int) (lo>>1) & 0xFFFF);
+			
+			if (decoded)
+				Dbprintf("Format Len: %dbits - FC: %d - Card: %d",
+					(unsigned int) bitlen, (unsigned int) fc, (unsigned int) cardnum);
+
 			if (findone){
 				if (ledcontrol)	LED_A_OFF();
+				*high2 = hi2;
 				*high = hi;
 				*low = lo;
 				break;
@@ -1114,12 +1198,79 @@ void CmdIOdemodFSK(int findone, int *high, int *low, int ledcontrol)
  * and enlarge the gap ones.
  * Q5 tags seems to have issues when these values changes. 
  */
+
+ /*
+ // Original Timings for reference
+//note startgap must be sent after tag has been powered up for more than 3ms (per T5557 ds)
+ 
 #define START_GAP 31*8 // was 250 // SPEC:  1*8 to 50*8 - typ 15*8 (or 15fc)
 #define WRITE_GAP 20*8 // was 160 // SPEC:  1*8 to 20*8 - typ 10*8 (or 10fc)
 #define WRITE_0   18*8 // was 144 // SPEC: 16*8 to 32*8 - typ 24*8 (or 24fc)
 #define WRITE_1   50*8 // was 400 // SPEC: 48*8 to 64*8 - typ 56*8 (or 56fc)  432 for T55x7; 448 for E5550
 #define READ_GAP  15*8 
 
+*/
+/* Q5 timing datasheet:
+ * Type                  |  MIN   | Typical |  Max   |
+ * Start_Gap             |  10*8  |    ?    |  50*8  |
+ * Write_Gap Normal mode |   8*8  |   14*8  |  20*8  | 
+ * Write_Gap Fast Mode   |   8*8  |    ?    |  20*8  |
+ * Write_0   Normal mode |  16*8  |   24*8  |  32*8  |
+ * Write_1   Normal mode |  48*8  |   56*8  |  64*8  |
+ * Write_0   Fast Mode   |   8*8  |   12*8  |  16*8  |
+ * Write_1   Fast Mode   |  24*8  |   28*8  |  32*8  |
+*/
+
+/* T5557 timing datasheet:
+ * Type                  |  MIN   | Typical |  Max   |
+ * Start_Gap             |  10*8  |    ?    |  50*8  |
+ * Write_Gap Normal mode |   8*8  |50-150us |  30*8  | 
+ * Write_Gap Fast Mode   |   8*8  |    ?    |  20*8  |
+ * Write_0   Normal mode |  16*8  |   24*8  |  31*8  | 
+ * Write_1   Normal mode |  48*8  |   54*8  |  63*8  | 
+ * Write_0   Fast Mode   |   8*8  |   12*8  |  15*8  |
+ * Write_1   Fast Mode   |  24*8  |   28*8  |  31*8  |
+*/
+
+/* T5577C timing datasheet for Fixed-Bit-Length protocol (defualt):
+ * Type                  |  MIN   | Typical |  Max   |
+ * Start_Gap             |   8*8  |   15*8  |  50*8  |
+ * Write_Gap Normal mode |   8*8  |   10*8  |  20*8  | 
+ * Write_Gap Fast Mode   |   8*8  |   10*8  |  20*8  |
+ * Write_0   Normal mode |  16*8  |   24*8  |  32*8  | 
+ * Write_1   Normal mode |  48*8  |   56*8  |  64*8  | 
+ * Write_0   Fast Mode   |   8*8  |   12*8  |  16*8  |
+ * Write_1   Fast Mode   |  24*8  |   28*8  |  32*8  |
+*/
+
+// Structure to hold Timing values.  In future will be simplier to add user changable timings.
+typedef struct  {
+	uint16_t  START_GAP;
+	uint16_t  WRITE_GAP;
+	uint16_t  WRITE_0;
+	uint16_t  WRITE_1;
+	uint16_t  WRITE_2;
+	uint16_t  WRITE_3;
+	uint16_t  READ_GAP;
+} T55xx_Timing;
+
+// Set Initial/Default Values.  Note: *8 can occure when used.  This should keep things simplier here.
+T55xx_Timing T55xx_Timing_FixedBit = { 31 * 8   , 20 * 8   , 18 * 8 , 50 * 8 , 0      , 0      , 15 * 8   };
+T55xx_Timing T55xx_Timing_LLR      = { 31 * 8   , 20 * 8   , 18 * 8 , 50 * 8 , 0      , 0      , 15 * 8   };
+T55xx_Timing T55xx_Timing_Leading0 = { 31 * 8   , 20 * 8   , 18 * 8 , 40 * 8 , 0      , 0      , 15 * 8   };
+T55xx_Timing T55xx_Timing_1of4     = { 31 * 8   , 20 * 8   , 18 * 8 , 34 * 8 , 50 * 8 , 66 * 8 , 15 * 8   };
+
+// Some defines for readability
+#define T55xx_DLMode_Fixed         0 // Default Mode
+#define T55xx_DLMode_LLR           1 // Long Leading Reference
+#define T55xx_DLMode_Leading0      2 // Leading Zero
+#define T55xx_DLMode_1of4          3 // 1 of 4
+#define T55xx_LongLeadingReference 4 // Value to tell Write Bit to send long reference
+// Macro for code readability
+#define BitStream_Byte(X) ((X) >> 3)
+#define BitStream_Bit(X)  ((X) &  7)  
+
+
 void TurnReadLFOn(int delay) {
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);
 	// Give it a bit of time for the resonant antenna to settle.
@@ -1127,39 +1278,182 @@ void TurnReadLFOn(int delay) {
 }
 
 // Write one bit to card
-void T55xxWriteBit(int bit) {
-	if (!bit)
-		TurnReadLFOn(WRITE_0);
-	else
-		TurnReadLFOn(WRITE_1);
+void T55xxWriteBit(int bit, T55xx_Timing *Timings) {
+
+	// If bit = 4 Send Long Leading Reference which is 138 + WRITE_0	
+	// Dbprintf ("Bits : %d",bit);
+	switch (bit){
+		case 0 : TurnReadLFOn(Timings->WRITE_0);             break; // Send bit  0/00
+		case 1 : TurnReadLFOn(Timings->WRITE_1);             break; // Send bit  1/01
+		case 2 : TurnReadLFOn(Timings->WRITE_2);             break; // Send bits   10
+		case 3 : TurnReadLFOn(Timings->WRITE_3);             break; // Send bits   11
+		case 4 : TurnReadLFOn(Timings->WRITE_0 + (136 * 8)); break; // Send Long Leading Reference
+	}
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	WaitUS(WRITE_GAP);
+	WaitUS(Timings->WRITE_GAP);
 }
 
-// Send T5577 reset command then read stream (see if we can identify the start of the stream)
-void T55xxResetRead(void) {
-	LED_A_ON();
-	//clear buffer now so it does not interfere with timing later
-	BigBuf_Clear_keep_EM();
+// Function to abstract an Arbitrary length byte array to store bit pattern.
+// bit_array    - Array to hold data/bit pattern
+// start_offset - bit location to start storing new bits.
+// data         - upto 32 bits of data to store
+// num_bits     - how many bits (low x bits of data)  Max 32 bits at a time
+// max_len         - how many bytes can the bit_array hold (ensure no buffer overflow)
+// returns "Next" bit offset / bits stored (for next store)
+//int T55xx_SetBits (uint8_t *bit_array, int start_offset, uint32_t data      , int num_bits, int max_len)
+int T55xx_SetBits (uint8_t *BitStream, uint8_t start_offset, uint32_t data , uint8_t num_bits, uint8_t max_len)
+{
+	int8_t offset;
+	int8_t NextOffset = start_offset;
+
+	// Check if data will fit.
+	if ((start_offset + num_bits) <= (max_len*8)) {
+		// Loop through the data and store
+		for (offset = (num_bits-1); offset >= 0; offset--) {
+
+			if ((data >> offset) & 1)  BitStream[BitStream_Byte(NextOffset)] |= (1         << BitStream_Bit(NextOffset));     // Set the bit to 1
+			else                       BitStream[BitStream_Byte(NextOffset)] &= (0xff ^ (1 << BitStream_Bit(NextOffset)));    // Set the bit to 0
+
+			NextOffset++;
+		}
+	}
+	else {
+		// Note: This should never happen unless some code changes cause it.  
+		// So short message for coders when testing.
+		Dbprintf ("T55 too many bits"); 
+	}
+	return NextOffset;
+}
+
+// Send one downlink command to the card 
+void T55xx_SendCMD (uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t arg) { 
+
+	/*
+		arg bits
+		xxxxxxx1 0x01 PwdMode
+		xxxxxx1x 0x02 Page
+		xxxxx1xx 0x04 testMode
+		xxx11xxx 0x18 downlink mode
+		xx1xxxxx 0x20 !reg_readmode
+		x1xxxxxx 0x40 called for a read, so no data packet
+		1xxxxxxx 0x80 reset
+
+	*/
+	bool PwdMode      = ((arg & 0x01) == 0x01);
+	bool Page         =  (arg & 0x02);
+	bool testMode     = ((arg & 0x04) == 0x04);
+	uint8_t downlink_mode = (arg >> 3) & 0x03;
+	bool reg_readmode = ((arg & 0x20) == 0x20);
+	bool read_cmd     = ((arg & 0x40) == 0x40);
+	bool reset        =  (arg & 0x80);
+
+	uint8_t i = 0;
+	uint8_t BitStream[10];  // Max Downlink Command size ~74 bits, so 10 bytes (80 bits)
+	uint8_t BitStreamLen;
+	T55xx_Timing *Timing;
+	uint8_t SendBits;
+
+	// Assigning Downlink Timeing for write
+	switch (downlink_mode)
+	{
+		case T55xx_DLMode_Fixed    : Timing = &T55xx_Timing_FixedBit;  break; 
+		case T55xx_DLMode_LLR      : Timing = &T55xx_Timing_LLR;       break;
+		case T55xx_DLMode_Leading0 : Timing = &T55xx_Timing_Leading0;  break;
+		case T55xx_DLMode_1of4     : Timing = &T55xx_Timing_1of4;      break;
+		default:
+				Timing = &T55xx_Timing_FixedBit;
+	}
+
+	// Build Bit Stream to send.
+	memset (BitStream,0x00,sizeof(BitStream));
+	
+	BitStreamLen = 0; // Ensure 0 bit index to start.
+	
+	// Add Leading 0 and 1 of 4 reference bit
+	if ((downlink_mode == T55xx_DLMode_Leading0) || (downlink_mode == T55xx_DLMode_1of4))
+		BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, 0, 1,sizeof(BitStream)); 
+
+	// Add extra reference 0 for 1 of 4
+	if (downlink_mode == T55xx_DLMode_1of4)
+		BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, 0, 1,sizeof(BitStream)); 
+
+	// Add Opcode 
+	if (reset) {
+		//  Reset : r*) 00
+		BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, 0, 2,sizeof(BitStream)); 
+	}
+	else
+	{
+		if (testMode) Dbprintf("TestMODE");
+		BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen,testMode ? 0 : 1    , 1,sizeof(BitStream));
+		BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen,testMode ? 1 : Page , 1,sizeof(BitStream));
+
+		if (PwdMode) {
+			// Leading 0 and 1 of 4 00 fixed bits if passsword used		
+			if ((downlink_mode == T55xx_DLMode_Leading0) || (downlink_mode == T55xx_DLMode_1of4)) {
+				BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, 0, 2,sizeof(BitStream));
+			}
+			BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, Pwd, 32,sizeof(BitStream));
+		}
+
+		// Add Lock bit 0
+		if (!reg_readmode) BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, 0, 1,sizeof(BitStream));
+
+		// Add Data if a write command
+		if (!read_cmd)	BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, Data, 32,sizeof(BitStream));
+
+		// Add Address
+		if (!reg_readmode) BitStreamLen = T55xx_SetBits (BitStream, BitStreamLen, Block, 3,sizeof(BitStream));
+	}
 
+	// Send Bits to T55xx
 	// Set up FPGA, 125kHz
 	LFSetupFPGAForADC(95, true);
 	StartTicks();
 	// make sure tag is fully powered up...
 	WaitMS(5);
-	
 	// Trigger T55x7 in mode.
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	WaitUS(START_GAP);
+	WaitUS(Timing->START_GAP);
+
+	// If long leading 0 send long reference pulse
+	if (downlink_mode ==  T55xx_DLMode_LLR) 
+		T55xxWriteBit (T55xx_LongLeadingReference,Timing); // Send Long Leading Start Reference
+
+	if ((downlink_mode ==  T55xx_DLMode_1of4) && (BitStreamLen > 0)) { // 1 of 4 need to send 2 bits at a time
+		for ( i = 0; i < BitStreamLen-1; i+=2 ) {
+			SendBits  = (BitStream[BitStream_Byte(i  )] >> (BitStream_Bit(i  )) & 1) << 1;   // Bit i
+			SendBits += (BitStream[BitStream_Byte(i+1)] >> (BitStream_Bit(i+1)) & 1);        // Bit i+1;
+			T55xxWriteBit (SendBits & 3,Timing);
+		}
+	}
+	else {
+		for (i = 0; i < BitStreamLen; i++) {
+			SendBits = (BitStream[BitStream_Byte(i)] >> BitStream_Bit(i));
+			T55xxWriteBit (SendBits & 1,Timing);
+		}
+	}
+}
+
+// Send T5577 reset command then read stream (see if we can identify the start of the stream)
+void T55xxResetRead(void) {
+	LED_A_ON();
 
-	// reset tag - op code 00
-	T55xxWriteBit(0);
-	T55xxWriteBit(0);
+	//  send  r* 00 
+	uint8_t arg = 0x80;  // SendCMD will add correct reference mode based on flags (when added).
 
-	TurnReadLFOn(READ_GAP);
+	// Add in downlink_mode when ready
+	//    arg |= 0x00;  // dlmode << 3  (00 default - 08 leading 0 - 10 Fixed - 18 1 of 4 )
+
+	//clear buffer now so it does not interfere with timing later
+	BigBuf_Clear_keep_EM();
+
+	T55xx_SendCMD (0, 0, 0, arg); //, true);
+
+	TurnReadLFOn(T55xx_Timing_FixedBit.READ_GAP);
 
 	// Acquisition
-	DoPartialAcquisition(0, true, BigBuf_max_traceLen());
+	DoPartialAcquisition(0, true, BigBuf_max_traceLen(), 0);
 
 	// Turn the field off
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
@@ -1168,42 +1462,23 @@ void T55xxResetRead(void) {
 }
 
 // Write one card block in page 0, no lock
-void T55xxWriteBlockExt(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t arg) {
-	LED_A_ON();
-	bool PwdMode = arg & 0x1;
-	uint8_t Page = (arg & 0x2)>>1;
-	bool testMode = arg & 0x4;
-	uint32_t i = 0;
-
-	// Set up FPGA, 125kHz
-	LFSetupFPGAForADC(95, true);
-	StartTicks();
-	// make sure tag is fully powered up...
-	WaitMS(5);
-	// Trigger T55x7 in mode.
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	WaitUS(START_GAP);
-
-	if (testMode) Dbprintf("TestMODE");
-	// Std Opcode 10
-	T55xxWriteBit(testMode ? 0 : 1);
-	T55xxWriteBit(testMode ? 1 : Page); //Page 0
-
-	if (PwdMode) {
-		// Send Pwd
-		for (i = 0x80000000; i != 0; i >>= 1)
-			T55xxWriteBit(Pwd & i);
-	}
-	// Send Lock bit
-	T55xxWriteBit(0);
-
-	// Send Data
-	for (i = 0x80000000; i != 0; i >>= 1)
-		T55xxWriteBit(Data & i);
-
-	// Send Block number
-	for (i = 0x04; i != 0; i >>= 1)
-		T55xxWriteBit(Block & i);
+void T55xxWriteBlock(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t arg) {
+	/*
+		arg bits
+		xxxxxxx1 0x01 PwdMode
+		xxxxxx1x 0x02 Page
+		xxxxx1xx 0x04 testMode
+		xxx11xxx 0x18 downlink mode
+		xx1xxxxx 0x20 !reg_readmode
+		x1xxxxxx 0x40 called for a read, so no data packet
+		1xxxxxxx 0x80 reset
+	*/
+	
+	bool testMode = ((arg & 0x04) == 0x04);
+	arg &= (0xff ^ 0x40); // Called for a write, so ensure it is clear/0
+	
+	LED_A_ON ();
+	T55xx_SendCMD (Data, Block, Pwd, arg) ;//, false); 
 
 	// Perform write (nominal is 5.6 ms for T55x7 and 18ms for E5550,
 	// so wait a little more)
@@ -1232,57 +1507,43 @@ void T55xxWriteBlockExt(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t arg
 
 		//DoPartialAcquisition(20, true, 12000);
 	}
-
 	// turn field off
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	LED_A_OFF();
-}
 
-// Write one card block in page 0, no lock
-void T55xxWriteBlock(uint32_t Data, uint32_t Block, uint32_t Pwd, uint8_t arg) {
-	T55xxWriteBlockExt(Data, Block, Pwd, arg);
 	cmd_send(CMD_ACK,0,0,0,0,0);
+
+	LED_A_OFF ();
 }
 
 // Read one card block in page [page]
-void T55xxReadBlock(uint16_t arg0, uint8_t Block, uint32_t Pwd) {
+void T55xxReadBlock (uint16_t arg0, uint8_t Block, uint32_t Pwd) {//, struct T55xx_Timing *Timing) {
+
 	LED_A_ON();
-	bool PwdMode = arg0 & 0x1;
-	uint8_t Page = (arg0 & 0x2) >> 1;
-	uint32_t i = 0;
-	bool RegReadMode = (Block == 0xFF);//regular read mode
 
-	//clear buffer now so it does not interfere with timing later
-	BigBuf_Clear_ext(false);
+	/*
+		arg bits
+		xxxxxxx1 0x01 PwdMode
+		xxxxxx1x 0x02 Page
+		xxxxx1xx 0x04 testMode
+		xxx11xxx 0x18 downlink mode
+		xx1xxxxx 0x20 !reg_readmode
+		x1xxxxxx 0x40 called for a read, so no data packet
+		1xxxxxxx 0x80 reset
+	*/
+
+	// Set Read Flag to ensure SendCMD does not add "data" to the packet
+	arg0 |= 0x40;
 
+	// RegRead Mode true of block 0xff
+	if (Block == 0xff) arg0 |= 0x20;
+	
 	//make sure block is at max 7
 	Block &= 0x7;
 
-	// Set up FPGA, 125kHz to power up the tag
-	LFSetupFPGAForADC(95, true);
-	StartTicks();
-	// make sure tag is fully powered up...
-	WaitMS(5);
-	// Trigger T55x7 Direct Access Mode with start gap
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	WaitUS(START_GAP);
-
-	// Opcode 1[page]
-	T55xxWriteBit(1);
-	T55xxWriteBit(Page); //Page 0
-
-	if (PwdMode){
-		// Send Pwd
-		for (i = 0x80000000; i != 0; i >>= 1)
-			T55xxWriteBit(Pwd & i);
-	}
-	// Send a zero bit separation
-	T55xxWriteBit(0);
+	//clear buffer now so it does not interfere with timing later
+	BigBuf_Clear_ext(false);
 
-	// Send Block number (if direct access mode)
-	if (!RegReadMode)
-		for (i = 0x04; i != 0; i >>= 1)
-			T55xxWriteBit(Block & i);		
+	T55xx_SendCMD (0, Block, Pwd, arg0); //, true);
 
 	// Turn field on to read the response
 	// 137*8 seems to get to the start of data pretty well... 
@@ -1291,35 +1552,36 @@ void T55xxReadBlock(uint16_t arg0, uint8_t Block, uint32_t Pwd) {
 
 	// Acquisition
 	// Now do the acquisition
-	DoPartialAcquisition(0, true, 12000);
+	DoPartialAcquisition(0, true, 12000, 0);
 
 	// Turn the field off
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
 	cmd_send(CMD_ACK,0,0,0,0,0);    
+
 	LED_A_OFF();
 }
 
 void T55xxWakeUp(uint32_t Pwd){
 	LED_B_ON();
-	uint32_t i = 0;
-	
-	// Set up FPGA, 125kHz
-	LFSetupFPGAForADC(95, true);
-	StartTicks();
-	// make sure tag is fully powered up...
-	WaitMS(5);
-	
-	// Trigger T55x7 Direct Access Mode
-	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
-	WaitUS(START_GAP);
-	
-	// Opcode 10
-	T55xxWriteBit(1);
-	T55xxWriteBit(0); //Page 0
+	/*
+		arg bits
+		xxxxxxx1 0x01 PwdMode
+		xxxxxx1x 0x02 Page
+		xxxxx1xx 0x04 testMode
+		xxx11xxx 0x18 downlink mode
+		xx1xxxxx 0x20 !reg_readmode 
+		x1xxxxxx 0x40 called for a read, so no data packet
+		1xxxxxxx 0x80 reset
+	*/
 
-	// Send Pwd
-	for (i = 0x80000000; i != 0; i >>= 1)
-		T55xxWriteBit(Pwd & i);
+	// r* 10 (00) <pwd>   r* for llr , L0 and 1/4 - (00) for L0 and 1/4 - All handled in SendCMD
+	// So, default Opcode 10 and pwd.
+	uint8_t arg = 0x01 | 0x40 | 0x20; //Password Read Call no data | reg_read no block
+
+	// Add in downlink_mode when ready
+	//    arg |= 0x00;  // dlmode << 3  (00 default - 08 leading 0 - 10 Fixed - 18 1 of 4 )
+
+	T55xx_SendCMD (0, 0, Pwd, arg); //, true);
 
 	// Turn and leave field on to let the begin repeating transmission
 	TurnReadLFOn(20*1000);
@@ -1330,12 +1592,13 @@ void T55xxWakeUp(uint32_t Pwd){
 void WriteT55xx(uint32_t *blockdata, uint8_t startblock, uint8_t numblocks) {
 	// write last block first and config block last (if included)
 	for (uint8_t i = numblocks+startblock; i > startblock; i--) {
-		T55xxWriteBlockExt(blockdata[i-1],i-1,0,0);
+		T55xxWriteBlock(blockdata[i-1],i-1,0,0);//,false); //,&T55xx_Timing_FixedBit);
+		//T55xx_SendCMD (blockdata[i-1],i-1,0,0);//,false); //,&T55xx_Timing_FixedBit);
 	}
 }
 
-// Copy HID id to card and setup block 0 config
-void CopyHIDtoT55x7(uint32_t hi2, uint32_t hi, uint32_t lo, uint8_t longFMT) {
+// Copy a HID-like card (e.g. HID Proximity, Paradox) to a T55x7 compatible card
+void CopyHIDtoT55x7(uint32_t hi2, uint32_t hi, uint32_t lo, uint8_t longFMT, uint8_t preamble) {
 	uint32_t data[] = {0,0,0,0,0,0,0};
 	uint8_t last_block = 0;
 
@@ -1347,15 +1610,15 @@ void CopyHIDtoT55x7(uint32_t hi2, uint32_t hi, uint32_t lo, uint8_t longFMT) {
 		}
 		// Build the 6 data blocks for supplied 84bit ID
 		last_block = 6;
-		// load preamble (1D) & long format identifier (9E manchester encoded)
-		data[1] = 0x1D96A900 | (manchesterEncode2Bytes((hi2 >> 16) & 0xF) & 0xFF);
+		// load preamble & long format identifier (9E manchester encoded)
+		data[1] = (preamble << 24) | 0x96A900 | (manchesterEncode2Bytes((hi2 >> 16) & 0xF) & 0xFF);
 		// load raw id from hi2, hi, lo to data blocks (manchester encoded)
 		data[2] = manchesterEncode2Bytes(hi2 & 0xFFFF);
 		data[3] = manchesterEncode2Bytes(hi >> 16);
 		data[4] = manchesterEncode2Bytes(hi & 0xFFFF);
 		data[5] = manchesterEncode2Bytes(lo >> 16);
 		data[6] = manchesterEncode2Bytes(lo & 0xFFFF);
-	}	else {
+	} else {
 		// Ensure no more than 44 bits supplied
 		if (hi>0xFFF) {
 			DbpString("Tags can only have 44 bits.");
@@ -1364,7 +1627,7 @@ void CopyHIDtoT55x7(uint32_t hi2, uint32_t hi, uint32_t lo, uint8_t longFMT) {
 		// Build the 3 data blocks for supplied 44bit ID
 		last_block = 3;
 		// load preamble
-		data[1] = 0x1D000000 | (manchesterEncode2Bytes(hi) & 0xFFFFFF);
+		data[1] = (preamble << 24) | (manchesterEncode2Bytes(hi) & 0xFFFFFF);
 		data[2] = manchesterEncode2Bytes(lo >> 16);
 		data[3] = manchesterEncode2Bytes(lo & 0xFFFF);
 	}
@@ -1530,6 +1793,7 @@ void WriteEM410x(uint32_t card, uint32_t id_hi, uint32_t id_lo) {
 #define FWD_CMD_WRITE 0xA
 #define FWD_CMD_READ 0x9
 #define FWD_CMD_DISABLE 0x5
+#define FWD_CMD_PROTECT 0x3
 
 uint8_t forwardLink_data[64]; //array of forwarded bits
 uint8_t * forward_ptr; //ptr for forward message preparation
@@ -1643,7 +1907,7 @@ void SendForward(uint8_t fwd_bit_count) {
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);//field on
 	WaitUS(18*8); //18 cycles on (8us each)
 
-	// now start writting
+	// now start writting - each bit should be 32*8 total length
 	while(fwd_bit_sz-- > 0) { //prepare next bit modulation
 		if(((*fwd_write_ptr++) & 1) == 1)
 			WaitUS(32*8); //32 cycles at 125Khz (8us each)
@@ -1652,7 +1916,7 @@ void SendForward(uint8_t fwd_bit_count) {
 			FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
 			WaitUS(23*8); //23 cycles off (8us each)
 			FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | FPGA_LF_ADC_READER_FIELD);//field on
-			WaitUS(18*8); //18 cycles on (8us each)
+			WaitUS((32-23)*8); //remaining cycles on (8us each)
 		}
 	}
 }
@@ -1690,7 +1954,7 @@ void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
 	SendForward(fwd_bit_count);
 	WaitUS(400);
 	// Now do the acquisition
-	DoPartialAcquisition(20, true, 6000);
+	DoPartialAcquisition(20, true, 6000, 1000);
 	
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
 	LED_A_OFF();
@@ -1699,7 +1963,7 @@ void EM4xReadWord(uint8_t Address, uint32_t Pwd, uint8_t PwdMode) {
 
 void EM4xWriteWord(uint32_t flag, uint32_t Data, uint32_t Pwd) {
 	
-	bool PwdMode = (flag & 0xF);
+	bool PwdMode = (flag & 0x1);
 	uint8_t Address = (flag >> 8) & 0xFF;
 	uint8_t fwd_bit_count;
 
@@ -1723,7 +1987,40 @@ void EM4xWriteWord(uint32_t flag, uint32_t Data, uint32_t Pwd) {
 
 	WaitUS(6500);
 	//Capture response if one exists
-	DoPartialAcquisition(20, true, 6000);
+	DoPartialAcquisition(20, true, 6000, 1000);
+
+	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
+	LED_A_OFF();
+	cmd_send(CMD_ACK,0,0,0,0,0);
+}
+
+void EM4xProtect(uint32_t flag, uint32_t Data, uint32_t Pwd) {
+	
+	bool PwdMode = (flag & 0x1);
+	uint8_t fwd_bit_count;
+
+	//clear buffer now so it does not interfere with timing later
+	BigBuf_Clear_ext(false);
+
+	LED_A_ON();
+	StartTicks();
+	//If password mode do login
+	if (PwdMode) EM4xLogin(Pwd);
+
+	forward_ptr = forwardLink_data;
+	fwd_bit_count = Prepare_Cmd( FWD_CMD_PROTECT );
+
+	//unsure if this needs the full packet config...
+	fwd_bit_count += Prepare_Data( Data&0xFFFF, Data>>16 );
+
+	SendForward(fwd_bit_count);
+
+	//Wait for write to complete
+	//SpinDelay(10);
+
+	WaitUS(6500);
+	//Capture response if one exists
+	DoPartialAcquisition(20, true, 6000, 1000);
 
 	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF); // field off
 	LED_A_OFF();
@@ -1766,7 +2063,7 @@ void Cotag(uint32_t arg0) {
 	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
 
 	// Now set up the SSC to get the ADC samples that are now streaming at us.
-	FpgaSetupSsc();
+	FpgaSetupSsc(FPGA_MAJOR_MODE_LF_ADC);
 
 	// start clock - 1.5ticks is 1us
 	StartTicks();