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1 //-----------------------------------------------------------------------------
2 // This code is licensed to you under the terms of the GNU GPL, version 2 or,
3 // at your option, any later version. See the LICENSE.txt file for the text of
4 // the license.
5 //-----------------------------------------------------------------------------
6 // Miscellaneous routines for low frequency sampling.
7 //-----------------------------------------------------------------------------
8
9 #include "proxmark3.h"
10 #include "apps.h"
11 #include "util.h"
12 #include "string.h"
13 #include "lfsampling.h"
14 #include "usb_cdc.h" // for usb_poll_validate_length
15 //#include "ticks.h" // for StartTicks
16
17 sample_config config = { 1, 8, 1, 95, 0 } ;
18
19 void printConfig()
20 {
21 Dbprintf("LF Sampling config: ");
22 Dbprintf(" [q] divisor: %d ", config.divisor);
23 Dbprintf(" [b] bps: %d ", config.bits_per_sample);
24 Dbprintf(" [d] decimation: %d ", config.decimation);
25 Dbprintf(" [a] averaging: %d ", config.averaging);
26 Dbprintf(" [t] trigger threshold: %d ", config.trigger_threshold);
27 }
28
29
30 /**
31 * Called from the USB-handler to set the sampling configuration
32 * The sampling config is used for std reading and snooping.
33 *
34 * Other functions may read samples and ignore the sampling config,
35 * such as functions to read the UID from a prox tag or similar.
36 *
37 * Values set to '0' implies no change (except for averaging)
38 * @brief setSamplingConfig
39 * @param sc
40 */
41 void setSamplingConfig(sample_config *sc)
42 {
43 if(sc->divisor != 0) config.divisor = sc->divisor;
44 if(sc->bits_per_sample!= 0) config.bits_per_sample= sc->bits_per_sample;
45 if(sc->decimation!= 0) config.decimation= sc->decimation;
46 if(sc->trigger_threshold != -1) config.trigger_threshold= sc->trigger_threshold;
47
48 config.averaging= sc->averaging;
49 if(config.bits_per_sample > 8) config.bits_per_sample = 8;
50 if(config.decimation < 1) config.decimation = 1;
51
52 printConfig();
53 }
54
55 sample_config* getSamplingConfig()
56 {
57 return &config;
58 }
59
60 typedef struct {
61 uint8_t * buffer;
62 uint32_t numbits;
63 uint32_t position;
64 } BitstreamOut;
65
66 /**
67 * @brief Pushes bit onto the stream
68 * @param stream
69 * @param bit
70 */
71 void pushBit( BitstreamOut* stream, uint8_t bit)
72 {
73 int bytepos = stream->position >> 3; // divide by 8
74 int bitpos = stream->position & 7;
75 *(stream->buffer+bytepos) |= (bit > 0) << (7 - bitpos);
76 stream->position++;
77 stream->numbits++;
78 }
79
80 /**
81 * Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
82 * if not already loaded, sets divisor and starts up the antenna.
83 * @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
84 * 0 or 95 ==> 125 KHz
85 *
86 **/
87 void LFSetupFPGAForADC(int divisor, bool lf_field)
88 {
89 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
90 if ( (divisor == 1) || (divisor < 0) || (divisor > 255) )
91 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
92 else if (divisor == 0)
93 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
94 else
95 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
96
97 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
98
99 // Connect the A/D to the peak-detected low-frequency path.
100 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
101 // Give it a bit of time for the resonant antenna to settle.
102 SpinDelay(50);
103 // Now set up the SSC to get the ADC samples that are now streaming at us.
104 FpgaSetupSsc();
105 }
106
107 /**
108 * Does the sample acquisition. If threshold is specified, the actual sampling
109 * is not commenced until the threshold has been reached.
110 * This method implements decimation and quantization in order to
111 * be able to provide longer sample traces.
112 * Uses the following global settings:
113 * @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
114 * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
115 * @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
116 * value that will be used is the average value of the three samples.
117 * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
118 * to -1 to ignore threshold.
119 * @param silent - is true, now outputs are made. If false, dbprints the status
120 * @return the number of bits occupied by the samples.
121 */
122 uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold, bool silent, int bufsize)
123 {
124 //.
125 uint8_t *dest = BigBuf_get_addr();
126 bufsize = (bufsize > 0 && bufsize < BigBuf_max_traceLen()) ? bufsize : BigBuf_max_traceLen();
127
128 //memset(dest, 0, bufsize); //creates issues with cmdread (marshmellow)
129
130 if(bits_per_sample < 1) bits_per_sample = 1;
131 if(bits_per_sample > 8) bits_per_sample = 8;
132
133 if(decimation < 1) decimation = 1;
134
135 // Use a bit stream to handle the output
136 BitstreamOut data = { dest , 0, 0};
137 int sample_counter = 0;
138 uint8_t sample = 0;
139 //If we want to do averaging
140 uint32_t sample_sum =0 ;
141 uint32_t sample_total_numbers =0 ;
142 uint32_t sample_total_saved =0 ;
143
144 while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
145 WDT_HIT();
146 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
147 AT91C_BASE_SSC->SSC_THR = 0x43;
148 LED_D_ON();
149 }
150 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
151 sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
152 LED_D_OFF();
153 // threshold either high or low values 128 = center 0. if trigger = 178
154 if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-trigger_threshold))) //
155 continue;
156
157 trigger_threshold = 0;
158 sample_total_numbers++;
159
160 if(averaging)
161 {
162 sample_sum += sample;
163 }
164 //Check decimation
165 if(decimation > 1)
166 {
167 sample_counter++;
168 if(sample_counter < decimation) continue;
169 sample_counter = 0;
170 }
171 //Averaging
172 if(averaging && decimation > 1) {
173 sample = sample_sum / decimation;
174 sample_sum =0;
175 }
176 //Store the sample
177 sample_total_saved ++;
178 if(bits_per_sample == 8){
179 dest[sample_total_saved-1] = sample;
180 data.numbits = sample_total_saved << 3;//Get the return value correct
181 if(sample_total_saved >= bufsize) break;
182 }
183 else{
184 pushBit(&data, sample & 0x80);
185 if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
186 if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
187 if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
188 if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
189 if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
190 if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
191 //Not needed, 8bps is covered above
192 //if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
193 if((data.numbits >> 3) +1 >= bufsize) break;
194 }
195 }
196 }
197
198 if(!silent)
199 {
200 Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
201 Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
202 dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
203 }
204 return data.numbits;
205 }
206 /**
207 * @brief Does sample acquisition, ignoring the config values set in the sample_config.
208 * This method is typically used by tag-specific readers who just wants to read the samples
209 * the normal way
210 * @param trigger_threshold
211 * @param silent
212 * @return number of bits sampled
213 */
214 uint32_t DoAcquisition_default(int trigger_threshold, bool silent)
215 {
216 return DoAcquisition(1,8,0,trigger_threshold,silent,0);
217 }
218 uint32_t DoAcquisition_config( bool silent)
219 {
220 return DoAcquisition(config.decimation
221 ,config.bits_per_sample
222 ,config.averaging
223 ,config.trigger_threshold
224 ,silent
225 ,0);
226 }
227
228 uint32_t DoPartialAcquisition(int trigger_threshold, bool silent, int sample_size) {
229 return DoAcquisition(1,8,0,trigger_threshold,silent,sample_size);
230 }
231
232 uint32_t ReadLF(bool activeField, bool silent)
233 {
234 if (!silent) printConfig();
235 LFSetupFPGAForADC(config.divisor, activeField);
236 // Now call the acquisition routine
237 return DoAcquisition_config(silent);
238 }
239
240 /**
241 * Initializes the FPGA for reader-mode (field on), and acquires the samples.
242 * @return number of bits sampled
243 **/
244 uint32_t SampleLF(bool printCfg)
245 {
246 uint32_t ret = ReadLF(true, printCfg);
247 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
248 return ret;
249 }
250 /**
251 * Initializes the FPGA for snoop-mode (field off), and acquires the samples.
252 * @return number of bits sampled
253 **/
254
255 uint32_t SnoopLF()
256 {
257 uint32_t ret = ReadLF(false, true);
258 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
259 return ret;
260 }
261
262 /**
263 * acquisition of T55x7 LF signal. Similart to other LF, but adjusted with @marshmellows thresholds
264 * the data is collected in BigBuf.
265 **/
266 void doT55x7Acquisition(size_t sample_size) {
267
268 #define T55xx_READ_UPPER_THRESHOLD 128+60 // 60 grph
269 #define T55xx_READ_LOWER_THRESHOLD 128-60 // -60 grph
270 #define T55xx_READ_TOL 5
271
272 uint8_t *dest = BigBuf_get_addr();
273 uint16_t bufsize = BigBuf_max_traceLen();
274
275 if ( bufsize > sample_size )
276 bufsize = sample_size;
277
278 uint16_t i = 0;
279 bool startFound = false;
280 bool highFound = false;
281 bool lowFound = false;
282 uint8_t curSample = 0;
283 uint8_t lastSample = 0;
284 uint16_t skipCnt = 0;
285 while(!BUTTON_PRESS() && !usb_poll_validate_length() && skipCnt<1000 && i<bufsize ) {
286 WDT_HIT();
287 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
288 AT91C_BASE_SSC->SSC_THR = 0x43;
289 LED_D_ON();
290 }
291 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
292 curSample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
293 LED_D_OFF();
294
295 // skip until the first high sample above threshold
296 if (!startFound && curSample > T55xx_READ_UPPER_THRESHOLD) {
297 //if (curSample > lastSample)
298 // lastSample = curSample;
299 highFound = true;
300 } else if (!highFound) {
301 skipCnt++;
302 continue;
303 }
304 // skip until the first Low sample below threshold
305 if (!startFound && curSample < T55xx_READ_LOWER_THRESHOLD) {
306 //if (curSample > lastSample)
307 lastSample = curSample;
308 lowFound = true;
309 } else if (!lowFound) {
310 skipCnt++;
311 continue;
312 }
313
314
315 // skip until first high samples begin to change
316 if (startFound || curSample > T55xx_READ_LOWER_THRESHOLD+T55xx_READ_TOL){
317 // if just found start - recover last sample
318 if (!startFound) {
319 dest[i++] = lastSample;
320 startFound = true;
321 }
322 // collect samples
323 dest[i++] = curSample;
324 }
325 }
326 }
327 }
328
329 /**
330 * acquisition of Cotag LF signal. Similart to other LF, since the Cotag has such long datarate RF/384
331 * and is Manchester?, we directly gather the manchester data into bigbuff
332 **/
333 #define COTAG_T1 384
334 #define COTAG_T2 (COTAG_T1>>1)
335 #define COTAG_ONE_THRESHOLD 128+30
336 #define COTAG_ZERO_THRESHOLD 128-30
337 #ifndef COTAG_BITS
338 #define COTAG_BITS 264
339 #endif
340 void doCotagAcquisition(size_t sample_size) {
341
342 uint8_t *dest = BigBuf_get_addr();
343 uint16_t bufsize = BigBuf_max_traceLen();
344
345 if ( bufsize > sample_size )
346 bufsize = sample_size;
347
348 dest[0] = 0;
349 uint8_t sample = 0, firsthigh = 0, firstlow = 0;
350 uint16_t i = 0;
351
352 while (!BUTTON_PRESS() && !usb_poll_validate_length() && (i < bufsize) ) {
353 WDT_HIT();
354 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
355 AT91C_BASE_SSC->SSC_THR = 0x43;
356 LED_D_ON();
357 }
358
359 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
360 sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
361 LED_D_OFF();
362
363 // find first peak
364 if ( !firsthigh ) {
365 if (sample < COTAG_ONE_THRESHOLD)
366 continue;
367 firsthigh = 1;
368 }
369 if ( !firstlow ){
370 if (sample > COTAG_ZERO_THRESHOLD )
371 continue;
372 firstlow = 1;
373 }
374
375 ++i;
376
377 if ( sample > COTAG_ONE_THRESHOLD)
378 dest[i] = 255;
379 else if ( sample < COTAG_ZERO_THRESHOLD)
380 dest[i] = 0;
381 else
382 dest[i] = dest[i-1];
383 }
384 }
385 }
386
387 uint32_t doCotagAcquisitionManchester() {
388
389 uint8_t *dest = BigBuf_get_addr();
390 uint16_t bufsize = BigBuf_max_traceLen();
391
392 if ( bufsize > COTAG_BITS )
393 bufsize = COTAG_BITS;
394
395 dest[0] = 0;
396 uint8_t sample = 0, firsthigh = 0, firstlow = 0;
397 uint16_t sample_counter = 0, period = 0;
398 uint8_t curr = 0, prev = 0;
399
400 while (!BUTTON_PRESS() && !usb_poll_validate_length() && (sample_counter < bufsize) ) {
401 WDT_HIT();
402 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
403 AT91C_BASE_SSC->SSC_THR = 0x43;
404 LED_D_ON();
405 }
406
407 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
408 sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
409 LED_D_OFF();
410
411 // find first peak
412 if ( !firsthigh ) {
413 if (sample < COTAG_ONE_THRESHOLD)
414 continue;
415 firsthigh = 1;
416 }
417
418 if ( !firstlow ){
419 if (sample > COTAG_ZERO_THRESHOLD )
420 continue;
421 firstlow = 1;
422 }
423
424 // set sample 255, 0, or previous
425 if ( sample > COTAG_ONE_THRESHOLD){
426 prev = curr;
427 curr = 1;
428 }
429 else if ( sample < COTAG_ZERO_THRESHOLD) {
430 prev = curr;
431 curr = 0;
432 }
433 else {
434 curr = prev;
435 }
436
437 // full T1 periods,
438 if ( period > 0 ) {
439 --period;
440 continue;
441 }
442
443 dest[sample_counter] = curr;
444 ++sample_counter;
445 period = COTAG_T1;
446 }
447 }
448 return sample_counter;
449 }
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