[proxmark3-svn] / client / cmdlfti.c

//-----------------------------------------------------------------------------
// Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
//
// 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.
//-----------------------------------------------------------------------------
// Low frequency TI commands
//-----------------------------------------------------------------------------

#include <stdio.h>
#include <stdlib.h>
#include "crc16.h"
#include "proxmark3.h"
#include "data.h"
#include "ui.h"
#include "graph.h"
#include "cmdparser.h"
#include "cmdlfti.h"
#include "cmdmain.h"

static int CmdHelp(const char *Cmd);

int CmdTIDemod(const char *Cmd)
{
  /* MATLAB as follows:
    f_s = 2000000;  % sampling frequency
    f_l = 123200;   % low FSK tone
    f_h = 134200;   % high FSK tone

    T_l = 119e-6;   % low bit duration
    T_h = 130e-6;   % high bit duration

    l = 2*pi*ones(1, floor(f_s*T_l))*(f_l/f_s);
    h = 2*pi*ones(1, floor(f_s*T_h))*(f_h/f_s);

    l = sign(sin(cumsum(l)));
    h = sign(sin(cumsum(h)));
  */

  // 2M*16/134.2k = 238
  static const int LowTone[] = {
    1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,    -1, -1
  };
  // 2M*16/123.2k = 260
  static const int HighTone[] = {
    1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1,   -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1,      -1, -1, -1, -1, -1, -1, -1,
    1, 1, 1, 1, 1, 1, 1, 1
  };
	int lowLen = sizeof(LowTone)/sizeof(int);
	int highLen = sizeof(HighTone)/sizeof(int);
	int convLen = (highLen>lowLen)?highLen:lowLen;
	uint16_t crc;
	int i, j, TagType;
	int lowSum = 0, highSum = 0;;
	int lowTot = 0, highTot = 0;

	for (i = 0; i < GraphTraceLen - convLen; i++) {
		lowSum = 0;
		highSum = 0;;

		for (j = 0; j < lowLen; j++) {
			lowSum += LowTone[j]*GraphBuffer[i+j];
		}
		for (j = 0; j < highLen; j++) {
			highSum += HighTone[j]*GraphBuffer[i+j];
		}
		lowSum = abs((100*lowSum) / lowLen);
		highSum = abs((100*highSum) / highLen);
		lowSum = (lowSum<0)?-lowSum:lowSum;
		highSum = (highSum<0)?-highSum:highSum;

		GraphBuffer[i] = (highSum << 16) | lowSum;
	}

	for (i = 0; i < GraphTraceLen - convLen - 16; i++) {
		lowTot = 0;
		highTot = 0;
		// 16 and 15 are f_s divided by f_l and f_h, rounded
		for (j = 0; j < 16; j++) {
			lowTot += (GraphBuffer[i+j] & 0xffff);
		}
		for (j = 0; j < 15; j++) {
			highTot += (GraphBuffer[i+j] >> 16);
		}
		GraphBuffer[i] = lowTot - highTot;
	}

	GraphTraceLen -= (convLen + 16);

	RepaintGraphWindow();

	// TI tag data format is 16 prebits, 8 start bits, 64 data bits,
	// 16 crc CCITT bits, 8 stop bits, 15 end bits

	// the 16 prebits are always low
	// the 8 start and stop bits of a tag must match
	// the start/stop prebits of a ro tag are 01111110
	// the start/stop prebits of a rw tag are 11111110
	// the 15 end bits of a ro tag are all low
	// the 15 end bits of a rw tag match bits 15-1 of the data bits

	// Okay, so now we have unsliced soft decisions;
	// find bit-sync, and then get some bits.
	// look for 17 low bits followed by 6 highs (common pattern for ro and rw tags)
	int max = 0, maxPos = 0;
	for (i = 0; i < 6000; i++) {
		int j;
		int dec = 0;
		// searching 17 consecutive lows
		for (j = 0; j < 17*lowLen; j++) {
			dec -= GraphBuffer[i+j];
		}
		// searching 7 consecutive highs
		for (; j < 17*lowLen + 6*highLen; j++) {
			dec += GraphBuffer[i+j];
		}
		if (dec > max) {
			max = dec;
			maxPos = i;
		}
	}

	// place a marker in the buffer to visually aid location
	// of the start of sync
	GraphBuffer[maxPos] = 800;
	GraphBuffer[maxPos+1] = -800;

	// advance pointer to start of actual data stream (after 16 pre and 8 start bits)
	maxPos += 17*lowLen;
	maxPos += 6*highLen;

	// place a marker in the buffer to visually aid location
	// of the end of sync
	GraphBuffer[maxPos] = 800;
	GraphBuffer[maxPos+1] = -800;

	PrintAndLog("actual data bits start at sample %d", maxPos);

	PrintAndLog("length %d/%d", highLen, lowLen);

	uint8_t bits[1+64+16+8+16];
	bits[sizeof(bits)-1] = '\0';

	uint32_t shift3 = 0x7e000000, shift2 = 0, shift1 = 0, shift0 = 0;

	for (i = 0; i < ARRAYLEN(bits)-1; i++) {
		int high = 0;
		int low = 0;
		int j;
		for (j = 0; j < lowLen; j++) {
			low -= GraphBuffer[maxPos+j];
		}
		for (j = 0; j < highLen; j++) {
			high += GraphBuffer[maxPos+j];
		}

		if (high > low) {
			bits[i] = '1';
			maxPos += highLen;
			// bitstream arrives lsb first so shift right
			shift3 |= (1<<31);
		} else {
			bits[i] = '.';
			maxPos += lowLen;
		}

		// 128 bit right shift register
		shift0 = (shift0>>1) | (shift1 << 31);
		shift1 = (shift1>>1) | (shift2 << 31);
		shift2 = (shift2>>1) | (shift3 << 31);
		shift3 >>= 1;

		// place a marker in the buffer between bits to visually aid location
		GraphBuffer[maxPos] = 800;
		GraphBuffer[maxPos+1] = -800;
	}

	RepaintGraphWindow();
	
	PrintAndLog("Info: raw tag bits = %s", bits);

	TagType = (shift3>>8)&0xff;
	if ( TagType != ((shift0>>16)&0xff) ) {
		PrintAndLog("Error: start and stop bits do not match!");
		return 0;
	}
	else if (TagType == 0x7e) {
		PrintAndLog("Info: Readonly TI tag detected.");
		return 0;
	}
	else if (TagType == 0xfe) {
		PrintAndLog("Info: Rewriteable TI tag detected.");

		// 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;

		// align 16 bit "end bits" or "ident" into lower half of shift3
		shift3 >>= 16;

		// only 15 bits compare, last bit of ident is not valid
		if ( (shift3^shift0)&0x7fff ) {
		  PrintAndLog("Error: Ident mismatch!");
		}
		// 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
		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);
		
		//crc =  crc16_ccitt(message, sizeof(message);

		char *crcStr = (crc == (shift2&0xffff) ) ? "Passed" : "Failed";
	
		PrintAndLog("Tag data = %08X%08X  [Crc %04X %s]", shift1, shift0, crc, crcStr );

		if (crc != (shift2&0xffff))
			PrintAndLog("Error: CRC mismatch, calculated %04X, got %04X", crc, shift2&0xffff);
   
	}
	else {
		PrintAndLog("Unknown tag type.");
	}
	return 0;
}

// read a TI tag and return its ID
int CmdTIRead(const char *Cmd)
{
	UsbCommand c = {CMD_READ_TI_TYPE};
	clearCommandBuffer();
	SendCommand(&c);
	return 0;
}

// write new data to a r/w TI tag
int CmdTIWrite(const char *Cmd)
{
	int res = 0;
	UsbCommand c = {CMD_WRITE_TI_TYPE};
	res = sscanf(Cmd, "%012" SCNx64 " %012" SCNx64 " %012" SCNx64, &c.arg[0], &c.arg[1], &c.arg[2]);

	if (res == 2) c.arg[2]=0;
	if (res < 2) {
		PrintAndLog("Please specify the data as two hex strings, optionally the CRC as a third");
		return 1;
	}
	clearCommandBuffer();
	SendCommand(&c);
	return 0;
}

static command_t CommandTable[] = {
  {"help",      CmdHelp,        1, "This help"},
  {"demod",     CmdTIDemod,     1, "Demodulate raw bits for TI-type LF tag"},
  {"read",      CmdTIRead,      0, "Read and decode a TI 134 kHz tag"},
  {"write",     CmdTIWrite,     0, "Write new data to a r/w TI 134 kHz tag"},
  {NULL, NULL, 0, NULL}
};

int CmdLFTI(const char *Cmd){
	clearCommandBuffer();
	CmdsParse(CommandTable, Cmd);
	return 0;
}

int CmdHelp(const char *Cmd){
	CmdsHelp(CommandTable);
	return 0;
}
Commit	Line	Data
a553f267	1	//-----------------------------------------------------------------------------
	2	// Copyright (C) 2010 iZsh <izsh at fail0verflow.com>
	3	//
	4	// This code is licensed to you under the terms of the GNU GPL, version 2 or,
	5	// at your option, any later version. See the LICENSE.txt file for the text of
	6	// the license.
	7	//-----------------------------------------------------------------------------
	8	// Low frequency TI commands
	9	//-----------------------------------------------------------------------------
	10
7fe9b0b7	11	#include <stdio.h>
590f8ff9	12	#include <stdlib.h>
7fe9b0b7	13	#include "crc16.h"
902cb3c0	14	#include "proxmark3.h"
7fe9b0b7	15	#include "data.h"
	16	#include "ui.h"
	17	#include "graph.h"
	18	#include "cmdparser.h"
	19	#include "cmdlfti.h"
1a570b0a	20	#include "cmdmain.h"
7fe9b0b7	21
	22	static int CmdHelp(const char *Cmd);
	23
	24	int CmdTIDemod(const char *Cmd)
	25	{
	26	/* MATLAB as follows:
	27	f_s = 2000000; % sampling frequency
	28	f_l = 123200; % low FSK tone
	29	f_h = 134200; % high FSK tone
	30
	31	T_l = 119e-6; % low bit duration
	32	T_h = 130e-6; % high bit duration
	33
	34	l = 2piones(1, floor(f_sT_l))(f_l/f_s);
	35	h = 2piones(1, floor(f_sT_h))(f_h/f_s);
	36
	37	l = sign(sin(cumsum(l)));
	38	h = sign(sin(cumsum(h)));
	39	*/
	40
	41	// 2M*16/134.2k = 238
	42	static const int LowTone[] = {
	43	1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	44	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	45	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	46	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	47	1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	48	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	49	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	50	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	51	1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	52	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	53	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	54	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	55	1, 1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	56	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	57	1, 1, 1, 1, 1, 1, 1, 1, -1, -1
	58	};
	59	// 2M*16/123.2k = 260
	60	static const int HighTone[] = {
	61	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	62	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	63	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	64	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	65	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	66	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	67	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	68	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	69	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	70	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	71	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	72	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	73	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	74	1, 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	75	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	76	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, -1,
	77	1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1,
	78	1, 1, 1, 1, 1, 1, 1, 1
	79	};
1a570b0a	80	int lowLen = sizeof(LowTone)/sizeof(int);
	81	int highLen = sizeof(HighTone)/sizeof(int);
	82	int convLen = (highLen>lowLen)?highLen:lowLen;
	83	uint16_t crc;
	84	int i, j, TagType;
	85	int lowSum = 0, highSum = 0;;
	86	int lowTot = 0, highTot = 0;
	87
	88	for (i = 0; i < GraphTraceLen - convLen; i++) {
	89	lowSum = 0;
	90	highSum = 0;;
	91
	92	for (j = 0; j < lowLen; j++) {
	93	lowSum += LowTone[j]*GraphBuffer[i+j];
	94	}
	95	for (j = 0; j < highLen; j++) {
	96	highSum += HighTone[j]*GraphBuffer[i+j];
	97	}
	98	lowSum = abs((100*lowSum) / lowLen);
	99	highSum = abs((100*highSum) / highLen);
	100	lowSum = (lowSum<0)?-lowSum:lowSum;
	101	highSum = (highSum<0)?-highSum:highSum;
	102
	103	GraphBuffer[i] = (highSum << 16) \| lowSum;
	104	}
	105
	106	for (i = 0; i < GraphTraceLen - convLen - 16; i++) {
	107	lowTot = 0;
	108	highTot = 0;
	109	// 16 and 15 are f_s divided by f_l and f_h, rounded
	110	for (j = 0; j < 16; j++) {
	111	lowTot += (GraphBuffer[i+j] & 0xffff);
	112	}
	113	for (j = 0; j < 15; j++) {
	114	highTot += (GraphBuffer[i+j] >> 16);
	115	}
	116	GraphBuffer[i] = lowTot - highTot;
	117	}
	118
	119	GraphTraceLen -= (convLen + 16);
	120
	121	RepaintGraphWindow();
	122
	123	// TI tag data format is 16 prebits, 8 start bits, 64 data bits,
	124	// 16 crc CCITT bits, 8 stop bits, 15 end bits
	125
	126	// the 16 prebits are always low
	127	// the 8 start and stop bits of a tag must match
	128	// the start/stop prebits of a ro tag are 01111110
	129	// the start/stop prebits of a rw tag are 11111110
	130	// the 15 end bits of a ro tag are all low
	131	// the 15 end bits of a rw tag match bits 15-1 of the data bits
	132
	133	// Okay, so now we have unsliced soft decisions;
	134	// find bit-sync, and then get some bits.
	135	// look for 17 low bits followed by 6 highs (common pattern for ro and rw tags)
	136	int max = 0, maxPos = 0;
	137	for (i = 0; i < 6000; i++) {
	138	int j;
	139	int dec = 0;
	140	// searching 17 consecutive lows
	141	for (j = 0; j < 17*lowLen; j++) {
	142	dec -= GraphBuffer[i+j];
	143	}
144	// searching 7 consecutive highs
145	for (; j < 17lowLen + 6highLen; j++) {
146	dec += GraphBuffer[i+j];
147	}
148	if (dec > max) {
149	max = dec;
150	maxPos = i;
151	}
152	}
153
154	// place a marker in the buffer to visually aid location
155	// of the start of sync
156	GraphBuffer[maxPos] = 800;
157	GraphBuffer[maxPos+1] = -800;
158
159	// advance pointer to start of actual data stream (after 16 pre and 8 start bits)
160	maxPos += 17*lowLen;
161	maxPos += 6*highLen;
162
163	// place a marker in the buffer to visually aid location
164	// of the end of sync
165	GraphBuffer[maxPos] = 800;
166	GraphBuffer[maxPos+1] = -800;
167
168	PrintAndLog("actual data bits start at sample %d", maxPos);
169
170	PrintAndLog("length %d/%d", highLen, lowLen);
171
172	uint8_t bits[1+64+16+8+16];
173	bits[sizeof(bits)-1] = '\0';
174
175	uint32_t shift3 = 0x7e000000, shift2 = 0, shift1 = 0, shift0 = 0;
176
52eeaef5	177	for (i = 0; i < ARRAYLEN(bits)-1; i++) {
1a570b0a	178	int high = 0;
	179	int low = 0;
	180	int j;
	181	for (j = 0; j < lowLen; j++) {
	182	low -= GraphBuffer[maxPos+j];
	183	}
	184	for (j = 0; j < highLen; j++) {
	185	high += GraphBuffer[maxPos+j];
	186	}
	187
	188	if (high > low) {
	189	bits[i] = '1';
	190	maxPos += highLen;
	191	// bitstream arrives lsb first so shift right
	192	shift3 \|= (1<<31);
	193	} else {
	194	bits[i] = '.';
	195	maxPos += lowLen;
	196	}
	197
	198	// 128 bit right shift register
	199	shift0 = (shift0>>1) \| (shift1 << 31);
	200	shift1 = (shift1>>1) \| (shift2 << 31);
	201	shift2 = (shift2>>1) \| (shift3 << 31);
	202	shift3 >>= 1;
	203
	204	// place a marker in the buffer between bits to visually aid location
	205	GraphBuffer[maxPos] = 800;
	206	GraphBuffer[maxPos+1] = -800;
	207	}
3fc01243	208
	209	RepaintGraphWindow();
	210
1a570b0a	211	PrintAndLog("Info: raw tag bits = %s", bits);
	212
	213	TagType = (shift3>>8)&0xff;
	214	if ( TagType != ((shift0>>16)&0xff) ) {
	215	PrintAndLog("Error: start and stop bits do not match!");
	216	return 0;
	217	}
	218	else if (TagType == 0x7e) {
	219	PrintAndLog("Info: Readonly TI tag detected.");
	220	return 0;
	221	}
	222	else if (TagType == 0xfe) {
	223	PrintAndLog("Info: Rewriteable TI tag detected.");
	224
	225	// put 64 bit data into shift1 and shift0
	226	shift0 = (shift0>>24) \| (shift1 << 8);
	227	shift1 = (shift1>>24) \| (shift2 << 8);
	228
	229	// align 16 bit crc into lower half of shift2
	230	shift2 = ((shift2>>24) \| (shift3 << 8)) & 0x0ffff;
	231
	232	// align 16 bit "end bits" or "ident" into lower half of shift3
	233	shift3 >>= 16;
	234
	235	// only 15 bits compare, last bit of ident is not valid
	236	if ( (shift3^shift0)&0x7fff ) {
	237	PrintAndLog("Error: Ident mismatch!");
	238	}
	239	// WARNING the order of the bytes in which we calc crc below needs checking
	240	// i'm 99% sure the crc algorithm is correct, but it may need to eat the
	241	// bytes in reverse or something
	242	// calculate CRC
	243	crc=0;
	244	crc = update_crc16(crc, (shift0)&0xff);
	245	crc = update_crc16(crc, (shift0>>8)&0xff);
	246	crc = update_crc16(crc, (shift0>>16)&0xff);
	247	crc = update_crc16(crc, (shift0>>24)&0xff);
	248	crc = update_crc16(crc, (shift1)&0xff);
	249	crc = update_crc16(crc, (shift1>>8)&0xff);
	250	crc = update_crc16(crc, (shift1>>16)&0xff);
	251	crc = update_crc16(crc, (shift1>>24)&0xff);
	252
	253	//crc = crc16_ccitt(message, sizeof(message);
	254
	255	char *crcStr = (crc == (shift2&0xffff) ) ? "Passed" : "Failed";
	256
	257	PrintAndLog("Tag data = %08X%08X [Crc %04X %s]", shift1, shift0, crc, crcStr );
	258
	259	if (crc != (shift2&0xffff))
3fc01243	260	PrintAndLog("Error: CRC mismatch, calculated %04X, got %04X", crc, shift2&0xffff);
1a570b0a	261
	262	}
	263	else {
	264	PrintAndLog("Unknown tag type.");
	265	}
	266	return 0;
7fe9b0b7	267	}
	268
	269	// read a TI tag and return its ID
	270	int CmdTIRead(const char *Cmd)
	271	{
e9a92fe2	272	UsbCommand c = {CMD_READ_TI_TYPE};
1a570b0a	273	clearCommandBuffer();
e9a92fe2	274	SendCommand(&c);
e9a92fe2	275	return 0;
7fe9b0b7	276	}
	277
	278	// write new data to a r/w TI tag
	279	int CmdTIWrite(const char *Cmd)
	280	{
e9a92fe2	281	int res = 0;
1a570b0a	282	UsbCommand c = {CMD_WRITE_TI_TYPE};
9c624f67	283	res = sscanf(Cmd, "%012" SCNx64 " %012" SCNx64 " %012" SCNx64, &c.arg[0], &c.arg[1], &c.arg[2]);
e9a92fe2	284
e9a92fe2	285	if (res == 2) c.arg[2]=0;
e1ad67ea	286	if (res < 2) {
e9a92fe2	287	PrintAndLog("Please specify the data as two hex strings, optionally the CRC as a third");
e1ad67ea	288	return 1;
	289	}
	290	clearCommandBuffer();
	291	SendCommand(&c);
e9a92fe2	292	return 0;
7fe9b0b7	293	}
7fe9b0b7	294
e9a92fe2	295	static command_t CommandTable[] = {
7fe9b0b7	296	{"help", CmdHelp, 1, "This help"},
	297	{"demod", CmdTIDemod, 1, "Demodulate raw bits for TI-type LF tag"},
	298	{"read", CmdTIRead, 0, "Read and decode a TI 134 kHz tag"},
	299	{"write", CmdTIWrite, 0, "Write new data to a r/w TI 134 kHz tag"},
	300	{NULL, NULL, 0, NULL}
	301	};
	302
e9a92fe2	303	int CmdLFTI(const char *Cmd){
4c36581b	304	clearCommandBuffer();
	305	CmdsParse(CommandTable, Cmd);
	306	return 0;
7fe9b0b7	307	}
7fe9b0b7	308
e9a92fe2	309	int CmdHelp(const char *Cmd){
4c36581b	310	CmdsHelp(CommandTable);
4c36581b	311	return 0;
7fe9b0b7	312	}