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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"
31abe49f 13#include "lfsampling.h"
e04475c4 14#include "usb_cdc.h" // for usb_poll_validate_length
15//#include "ticks.h" // for StartTicks
10a8875c 16
0cd2a41a 17sample_config config = { 1, 8, 1, 95, 0 } ;
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18
19void printConfig()
20{
e2012d1b 21 Dbprintf("LF Sampling config: ");
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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 */
41void 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
55sample_config* getSamplingConfig()
56{
57 return &config;
58}
10a8875c 59
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60typedef struct {
61 uint8_t * buffer;
62 uint32_t numbits;
63 uint32_t position;
64} BitstreamOut;
65
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66/**
67 * @brief Pushes bit onto the stream
68 * @param stream
69 * @param bit
70 */
10a8875c 71void pushBit( BitstreamOut* stream, uint8_t bit)
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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}
10a8875c 79
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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**/
87void 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
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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 */
a37228c8 122uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold, bool silent, int bufsize)
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123{
124 //.
0644d5e3 125 uint8_t *dest = BigBuf_get_addr();
a37228c8 126 bufsize = (bufsize > 0 && bufsize < BigBuf_max_traceLen()) ? bufsize : BigBuf_max_traceLen();
0644d5e3 127
3cec7061 128 //memset(dest, 0, bufsize); //creates issues with cmdread (marshmellow)
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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
e04475c4 144 while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
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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();
b29d55f2 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))) //
31abe49f 155 continue;
b29d55f2 156
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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 */
214uint32_t DoAcquisition_default(int trigger_threshold, bool silent)
215{
a37228c8 216 return DoAcquisition(1,8,0,trigger_threshold,silent,0);
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217}
218uint32_t DoAcquisition_config( bool silent)
219{
220 return DoAcquisition(config.decimation
221 ,config.bits_per_sample
222 ,config.averaging
223 ,config.trigger_threshold
a37228c8 224 ,silent
225 ,0);
226}
227
228uint32_t DoPartialAcquisition(int trigger_threshold, bool silent, int sample_size) {
229 return DoAcquisition(1,8,0,trigger_threshold,silent,sample_size);
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230}
231
1fbf8956 232uint32_t ReadLF(bool activeField, bool silent)
31abe49f 233{
1fbf8956 234 if (!silent) printConfig();
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235 LFSetupFPGAForADC(config.divisor, activeField);
236 // Now call the acquisition routine
1fbf8956 237 return DoAcquisition_config(silent);
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238}
239
240/**
241* Initializes the FPGA for reader-mode (field on), and acquires the samples.
242* @return number of bits sampled
243**/
1fbf8956 244uint32_t SampleLF(bool printCfg)
31abe49f 245{
e04475c4 246 uint32_t ret = ReadLF(true, printCfg);
247 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
248 return ret;
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249}
250/**
251* Initializes the FPGA for snoop-mode (field off), and acquires the samples.
252* @return number of bits sampled
253**/
254
255uint32_t SnoopLF()
256{
e04475c4 257 uint32_t ret = ReadLF(false, true);
258 FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
259 return ret;
31abe49f 260}
7cfc777b 261
e04475c4 262/**
263* acquisition of Cotag LF signal. Similart to other LF, since the Cotag has such long datarate RF/384
264* and is Manchester?, we directly gather the manchester data into bigbuff
265**/
266#define COTAG_T1 384
267#define COTAG_T2 (COTAG_T1>>1)
268#define COTAG_ONE_THRESHOLD 128+30
269#define COTAG_ZERO_THRESHOLD 128-30
270#ifndef COTAG_BITS
271#define COTAG_BITS 264
272#endif
273void doCotagAcquisition(size_t sample_size) {
274
275 uint8_t *dest = BigBuf_get_addr();
276 uint16_t bufsize = BigBuf_max_traceLen();
277
278 if ( bufsize > sample_size )
279 bufsize = sample_size;
280
281 dest[0] = 0;
282 uint8_t sample = 0, firsthigh = 0, firstlow = 0;
283 uint16_t i = 0;
284
285 while (!BUTTON_PRESS() && !usb_poll_validate_length() && (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
292 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
293 sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
294 LED_D_OFF();
295
296 // find first peak
297 if ( !firsthigh ) {
298 if (sample < COTAG_ONE_THRESHOLD)
299 continue;
300 firsthigh = 1;
301 }
302 if ( !firstlow ){
303 if (sample > COTAG_ZERO_THRESHOLD )
304 continue;
305 firstlow = 1;
306 }
307
308 ++i;
309
310 if ( sample > COTAG_ONE_THRESHOLD)
311 dest[i] = 255;
312 else if ( sample < COTAG_ZERO_THRESHOLD)
313 dest[i] = 0;
314 else
315 dest[i] = dest[i-1];
316 }
317 }
318}
319
320uint32_t doCotagAcquisitionManchester() {
321
322 uint8_t *dest = BigBuf_get_addr();
323 uint16_t bufsize = BigBuf_max_traceLen();
324
325 if ( bufsize > COTAG_BITS )
326 bufsize = COTAG_BITS;
327
328 dest[0] = 0;
329 uint8_t sample = 0, firsthigh = 0, firstlow = 0;
330 uint16_t sample_counter = 0, period = 0;
331 uint8_t curr = 0, prev = 0;
332
333 while (!BUTTON_PRESS() && !usb_poll_validate_length() && (sample_counter < bufsize) ) {
334 WDT_HIT();
335 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
336 AT91C_BASE_SSC->SSC_THR = 0x43;
337 LED_D_ON();
338 }
339
340 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
341 sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
342 LED_D_OFF();
343
344 // find first peak
345 if ( !firsthigh ) {
346 if (sample < COTAG_ONE_THRESHOLD)
347 continue;
348 firsthigh = 1;
349 }
350
351 if ( !firstlow ){
352 if (sample > COTAG_ZERO_THRESHOLD )
353 continue;
354 firstlow = 1;
355 }
356
357 // set sample 255, 0, or previous
358 if ( sample > COTAG_ONE_THRESHOLD){
359 prev = curr;
360 curr = 1;
361 }
362 else if ( sample < COTAG_ZERO_THRESHOLD) {
363 prev = curr;
364 curr = 0;
365 }
366 else {
367 curr = prev;
368 }
369
370 // full T1 periods,
371 if ( period > 0 ) {
372 --period;
373 continue;
374 }
375
376 dest[sample_counter] = curr;
377 ++sample_counter;
378 period = COTAG_T1;
379 }
380 }
381 return sample_counter;
382}
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