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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 | ||
babca445 | 11 | #include "cmdlfti.h" |
12 | ||
7fe9b0b7 | 13 | #include <stdio.h> |
590f8ff9 | 14 | #include <stdlib.h> |
43534cba | 15 | #include <inttypes.h> |
7fe9b0b7 | 16 | #include "crc16.h" |
ad939de5 | 17 | #include "comms.h" |
7fe9b0b7 | 18 | #include "ui.h" |
19 | #include "graph.h" | |
20 | #include "cmdparser.h" | |
babca445 | 21 | #include "util.h" |
7fe9b0b7 | 22 | |
23 | static int CmdHelp(const char *Cmd); | |
24 | ||
25 | int CmdTIDemod(const char *Cmd) | |
26 | { | |
27 | /* MATLAB as follows: | |
28 | f_s = 2000000; % sampling frequency | |
29 | f_l = 123200; % low FSK tone | |
30 | f_h = 134200; % high FSK tone | |
31 | ||
32 | T_l = 119e-6; % low bit duration | |
33 | T_h = 130e-6; % high bit duration | |
34 | ||
35 | l = 2*pi*ones(1, floor(f_s*T_l))*(f_l/f_s); | |
36 | h = 2*pi*ones(1, floor(f_s*T_h))*(f_h/f_s); | |
37 | ||
38 | l = sign(sin(cumsum(l))); | |
39 | h = sign(sin(cumsum(h))); | |
40 | */ | |
41 | ||
42 | // 2M*16/134.2k = 238 | |
43 | static const int LowTone[] = { | |
44 | 1, 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, | |
48 | 1, 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, | |
52 | 1, 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, | |
56 | 1, 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, -1, -1, -1, -1, -1, -1, | |
58 | 1, 1, 1, 1, 1, 1, 1, 1, -1, -1 | |
59 | }; | |
60 | // 2M*16/123.2k = 260 | |
61 | static const int HighTone[] = { | |
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, -1, | |
67 | 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, -1, | |
72 | 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, -1, | |
78 | 1, 1, 1, 1, 1, 1, 1, -1, -1, -1, -1, -1, -1, -1, | |
79 | 1, 1, 1, 1, 1, 1, 1, 1 | |
80 | }; | |
81 | int lowLen = sizeof(LowTone)/sizeof(int); | |
82 | int highLen = sizeof(HighTone)/sizeof(int); | |
83 | int convLen = (highLen>lowLen)?highLen:lowLen; | |
84 | uint16_t crc; | |
85 | int i, j, TagType; | |
86 | int lowSum = 0, highSum = 0;; | |
87 | int lowTot = 0, highTot = 0; | |
88 | ||
89 | for (i = 0; i < GraphTraceLen - convLen; i++) { | |
90 | lowSum = 0; | |
91 | highSum = 0;; | |
92 | ||
93 | for (j = 0; j < lowLen; j++) { | |
94 | lowSum += LowTone[j]*GraphBuffer[i+j]; | |
95 | } | |
96 | for (j = 0; j < highLen; j++) { | |
97 | highSum += HighTone[j]*GraphBuffer[i+j]; | |
98 | } | |
99 | lowSum = abs((100*lowSum) / lowLen); | |
100 | highSum = abs((100*highSum) / highLen); | |
101 | lowSum = (lowSum<0)?-lowSum:lowSum; | |
102 | highSum = (highSum<0)?-highSum:highSum; | |
103 | ||
104 | GraphBuffer[i] = (highSum << 16) | lowSum; | |
105 | } | |
106 | ||
107 | for (i = 0; i < GraphTraceLen - convLen - 16; i++) { | |
108 | lowTot = 0; | |
109 | highTot = 0; | |
110 | // 16 and 15 are f_s divided by f_l and f_h, rounded | |
111 | for (j = 0; j < 16; j++) { | |
112 | lowTot += (GraphBuffer[i+j] & 0xffff); | |
113 | } | |
114 | for (j = 0; j < 15; j++) { | |
115 | highTot += (GraphBuffer[i+j] >> 16); | |
116 | } | |
117 | GraphBuffer[i] = lowTot - highTot; | |
118 | } | |
119 | ||
120 | GraphTraceLen -= (convLen + 16); | |
121 | ||
122 | RepaintGraphWindow(); | |
123 | ||
124 | // TI tag data format is 16 prebits, 8 start bits, 64 data bits, | |
125 | // 16 crc CCITT bits, 8 stop bits, 15 end bits | |
126 | ||
127 | // the 16 prebits are always low | |
128 | // the 8 start and stop bits of a tag must match | |
129 | // the start/stop prebits of a ro tag are 01111110 | |
130 | // the start/stop prebits of a rw tag are 11111110 | |
131 | // the 15 end bits of a ro tag are all low | |
132 | // the 15 end bits of a rw tag match bits 15-1 of the data bits | |
133 | ||
134 | // Okay, so now we have unsliced soft decisions; | |
135 | // find bit-sync, and then get some bits. | |
136 | // look for 17 low bits followed by 6 highs (common pattern for ro and rw tags) | |
137 | int max = 0, maxPos = 0; | |
138 | for (i = 0; i < 6000; i++) { | |
139 | int j; | |
140 | int dec = 0; | |
141 | // searching 17 consecutive lows | |
142 | for (j = 0; j < 17*lowLen; j++) { | |
143 | dec -= GraphBuffer[i+j]; | |
144 | } | |
145 | // searching 7 consecutive highs | |
146 | for (; j < 17*lowLen + 6*highLen; j++) { | |
147 | dec += GraphBuffer[i+j]; | |
148 | } | |
149 | if (dec > max) { | |
150 | max = dec; | |
151 | maxPos = i; | |
152 | } | |
153 | } | |
154 | ||
155 | // place a marker in the buffer to visually aid location | |
156 | // of the start of sync | |
157 | GraphBuffer[maxPos] = 800; | |
158 | GraphBuffer[maxPos+1] = -800; | |
159 | ||
160 | // advance pointer to start of actual data stream (after 16 pre and 8 start bits) | |
161 | maxPos += 17*lowLen; | |
162 | maxPos += 6*highLen; | |
163 | ||
164 | // place a marker in the buffer to visually aid location | |
165 | // of the end of sync | |
166 | GraphBuffer[maxPos] = 800; | |
167 | GraphBuffer[maxPos+1] = -800; | |
168 | ||
169 | PrintAndLog("actual data bits start at sample %d", maxPos); | |
170 | ||
171 | PrintAndLog("length %d/%d", highLen, lowLen); | |
172 | ||
173 | uint8_t bits[1+64+16+8+16]; | |
174 | bits[sizeof(bits)-1] = '\0'; | |
175 | ||
176 | uint32_t shift3 = 0x7e000000, shift2 = 0, shift1 = 0, shift0 = 0; | |
177 | ||
178 | for (i = 0; i < arraylen(bits)-1; i++) { | |
179 | int high = 0; | |
180 | int low = 0; | |
181 | int j; | |
182 | for (j = 0; j < lowLen; j++) { | |
183 | low -= GraphBuffer[maxPos+j]; | |
184 | } | |
185 | for (j = 0; j < highLen; j++) { | |
186 | high += GraphBuffer[maxPos+j]; | |
187 | } | |
188 | ||
189 | if (high > low) { | |
190 | bits[i] = '1'; | |
191 | maxPos += highLen; | |
192 | // bitstream arrives lsb first so shift right | |
193 | shift3 |= (1<<31); | |
194 | } else { | |
195 | bits[i] = '.'; | |
196 | maxPos += lowLen; | |
197 | } | |
198 | ||
199 | // 128 bit right shift register | |
200 | shift0 = (shift0>>1) | (shift1 << 31); | |
201 | shift1 = (shift1>>1) | (shift2 << 31); | |
202 | shift2 = (shift2>>1) | (shift3 << 31); | |
203 | shift3 >>= 1; | |
204 | ||
205 | // place a marker in the buffer between bits to visually aid location | |
206 | GraphBuffer[maxPos] = 800; | |
207 | GraphBuffer[maxPos+1] = -800; | |
208 | } | |
209 | PrintAndLog("Info: raw tag bits = %s", bits); | |
210 | ||
211 | TagType = (shift3>>8)&0xff; | |
212 | if ( TagType != ((shift0>>16)&0xff) ) { | |
213 | PrintAndLog("Error: start and stop bits do not match!"); | |
214 | return 0; | |
215 | } | |
216 | else if (TagType == 0x7e) { | |
217 | PrintAndLog("Info: Readonly TI tag detected."); | |
218 | return 0; | |
219 | } | |
220 | else if (TagType == 0xfe) { | |
221 | PrintAndLog("Info: Rewriteable TI tag detected."); | |
222 | ||
223 | // put 64 bit data into shift1 and shift0 | |
224 | shift0 = (shift0>>24) | (shift1 << 8); | |
225 | shift1 = (shift1>>24) | (shift2 << 8); | |
226 | ||
227 | // align 16 bit crc into lower half of shift2 | |
228 | shift2 = ((shift2>>24) | (shift3 << 8)) & 0x0ffff; | |
229 | ||
230 | // align 16 bit "end bits" or "ident" into lower half of shift3 | |
231 | shift3 >>= 16; | |
232 | ||
233 | // only 15 bits compare, last bit of ident is not valid | |
234 | if ( (shift3^shift0)&0x7fff ) { | |
235 | PrintAndLog("Error: Ident mismatch!"); | |
236 | } | |
237 | // WARNING the order of the bytes in which we calc crc below needs checking | |
238 | // i'm 99% sure the crc algorithm is correct, but it may need to eat the | |
239 | // bytes in reverse or something | |
240 | // calculate CRC | |
241 | crc=0; | |
242 | crc = update_crc16(crc, (shift0)&0xff); | |
243 | crc = update_crc16(crc, (shift0>>8)&0xff); | |
244 | crc = update_crc16(crc, (shift0>>16)&0xff); | |
245 | crc = update_crc16(crc, (shift0>>24)&0xff); | |
246 | crc = update_crc16(crc, (shift1)&0xff); | |
247 | crc = update_crc16(crc, (shift1>>8)&0xff); | |
248 | crc = update_crc16(crc, (shift1>>16)&0xff); | |
249 | crc = update_crc16(crc, (shift1>>24)&0xff); | |
250 | PrintAndLog("Info: Tag data = %08X%08X", shift1, shift0); | |
251 | if (crc != (shift2&0xffff)) { | |
252 | PrintAndLog("Error: CRC mismatch, calculated %04X, got ^04X", crc, shift2&0xffff); | |
253 | } else { | |
254 | PrintAndLog("Info: CRC %04X is good", crc); | |
255 | } | |
256 | } | |
257 | else { | |
258 | PrintAndLog("Unknown tag type."); | |
259 | return 0; | |
260 | } | |
261 | return 0; | |
262 | } | |
263 | ||
264 | // read a TI tag and return its ID | |
265 | int CmdTIRead(const char *Cmd) | |
266 | { | |
267 | UsbCommand c = {CMD_READ_TI_TYPE}; | |
268 | SendCommand(&c); | |
269 | return 0; | |
270 | } | |
271 | ||
272 | // write new data to a r/w TI tag | |
273 | int CmdTIWrite(const char *Cmd) | |
274 | { | |
275 | UsbCommand c = {CMD_WRITE_TI_TYPE}; | |
276 | int res = 0; | |
277 | ||
4c16ae80 | 278 | res = sscanf(Cmd, "%012" SCNx64 " %012" SCNx64 " %012" SCNx64 "", &c.arg[0], &c.arg[1], &c.arg[2]); |
5c2b11eb | 279 | |
7fe9b0b7 | 280 | if (res == 2) c.arg[2]=0; |
281 | if (res < 2) | |
282 | PrintAndLog("Please specify the data as two hex strings, optionally the CRC as a third"); | |
283 | else | |
284 | SendCommand(&c); | |
285 | return 0; | |
286 | } | |
287 | ||
288 | static command_t CommandTable[] = | |
289 | { | |
290 | {"help", CmdHelp, 1, "This help"}, | |
291 | {"demod", CmdTIDemod, 1, "Demodulate raw bits for TI-type LF tag"}, | |
292 | {"read", CmdTIRead, 0, "Read and decode a TI 134 kHz tag"}, | |
293 | {"write", CmdTIWrite, 0, "Write new data to a r/w TI 134 kHz tag"}, | |
294 | {NULL, NULL, 0, NULL} | |
295 | }; | |
296 | ||
297 | int CmdLFTI(const char *Cmd) | |
298 | { | |
299 | CmdsParse(CommandTable, Cmd); | |
300 | return 0; | |
301 | } | |
302 | ||
303 | int CmdHelp(const char *Cmd) | |
304 | { | |
305 | CmdsHelp(CommandTable); | |
306 | return 0; | |
307 | } |