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