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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 "usb_cdc.h" // for usb_poll_validate_length
14#include "lfsampling.h"
15
16sample_config config = { 1, 8, 1, 95, 0 } ;
17
18void printConfig()
19{
20 Dbprintf("LF Sampling config: ");
21 Dbprintf(" [q] divisor: %d ", config.divisor);
22 Dbprintf(" [b] bps: %d ", config.bits_per_sample);
23 Dbprintf(" [d] decimation: %d ", config.decimation);
24 Dbprintf(" [a] averaging: %d ", config.averaging);
25 Dbprintf(" [t] trigger threshold: %d ", config.trigger_threshold);
26}
27
28
29/**
30 * Called from the USB-handler to set the sampling configuration
31 * The sampling config is used for std reading and snooping.
32 *
33 * Other functions may read samples and ignore the sampling config,
34 * such as functions to read the UID from a prox tag or similar.
35 *
36 * Values set to '0' implies no change (except for averaging)
37 * @brief setSamplingConfig
38 * @param sc
39 */
40void setSamplingConfig(sample_config *sc)
41{
42 if(sc->divisor != 0) config.divisor = sc->divisor;
43 if(sc->bits_per_sample != 0) config.bits_per_sample = sc->bits_per_sample;
44 if(sc->decimation != 0) config.decimation = sc->decimation;
45 if(sc->trigger_threshold != -1) config.trigger_threshold = sc->trigger_threshold;
46
47 config.averaging = sc->averaging;
48 if(config.bits_per_sample > 8) config.bits_per_sample = 8;
49 if(config.decimation < 1) config.decimation = 1;
50
51 printConfig();
52}
53
54sample_config* getSamplingConfig()
55{
56 return &config;
57}
58
59typedef struct {
60 uint8_t * buffer;
61 uint32_t numbits;
62 uint32_t position;
63} BitstreamOut;
64
65/**
66 * @brief Pushes bit onto the stream
67 * @param stream
68 * @param bit
69 */
70void pushBit( BitstreamOut* stream, uint8_t bit)
71{
72 int bytepos = stream->position >> 3; // divide by 8
73 int bitpos = stream->position & 7;
74 *(stream->buffer+bytepos) |= (bit > 0) << (7 - bitpos);
75 stream->position++;
76 stream->numbits++;
77}
78
79/**
80* Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
81* if not already loaded, sets divisor and starts up the antenna.
82* @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
83* 0 or 95 ==> 125 KHz
84*
85**/
86void LFSetupFPGAForADC(int divisor, bool lf_field)
87{
88 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
89 if ( (divisor == 1) || (divisor < 0) || (divisor > 255) )
90 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
91 else if (divisor == 0)
92 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
93 else
94 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
95
96 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
97
98 // Connect the A/D to the peak-detected low-frequency path.
99 SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
100 // Give it a bit of time for the resonant antenna to settle.
101 SpinDelay(50);
102 // Now set up the SSC to get the ADC samples that are now streaming at us.
103 FpgaSetupSsc();
104}
105
106/**
107 * Does the sample acquisition. If threshold is specified, the actual sampling
108 * is not commenced until the threshold has been reached.
109 * This method implements decimation and quantization in order to
110 * be able to provide longer sample traces.
111 * Uses the following global settings:
112 * @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
113 * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
114 * @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
115 * value that will be used is the average value of the three samples.
116 * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
117 * to -1 to ignore threshold.
118 * @param silent - is true, now outputs are made. If false, dbprints the status
119 * @return the number of bits occupied by the samples.
120 */
121uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold,bool silent)
122{
123 //bigbuf, to hold the aquired raw data signal
124 uint8_t *dest = BigBuf_get_addr();
125 uint16_t bufsize = BigBuf_max_traceLen();
126
127 //BigBuf_Clear_ext(false); //creates issues with cmdread (marshmellow)
128
129 if(bits_per_sample < 1) bits_per_sample = 1;
130 if(bits_per_sample > 8) bits_per_sample = 8;
131
132 if(decimation < 1) decimation = 1;
133
134 // Use a bit stream to handle the output
135 BitstreamOut data = { dest , 0, 0};
136 int sample_counter = 0;
137 uint8_t sample = 0;
138 //If we want to do averaging
139 uint32_t sample_sum =0 ;
140 uint32_t sample_total_numbers =0 ;
141 uint32_t sample_total_saved =0 ;
142
143 while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
144 WDT_HIT();
145 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
146 AT91C_BASE_SSC->SSC_THR = 0x43;
147 LED_D_ON();
148 }
149 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
150 sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
151 LED_D_OFF();
152 // threshold either high or low values 128 = center 0. if trigger = 178
153 if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-trigger_threshold))) //
154 continue;
155
156 trigger_threshold = 0;
157 sample_total_numbers++;
158
159 if(averaging)
160 {
161 sample_sum += sample;
162 }
163 //Check decimation
164 if(decimation > 1)
165 {
166 sample_counter++;
167 if(sample_counter < decimation) continue;
168 sample_counter = 0;
169 }
170 //Averaging
171 if(averaging && decimation > 1) {
172 sample = sample_sum / decimation;
173 sample_sum =0;
174 }
175 //Store the sample
176 sample_total_saved ++;
177 if(bits_per_sample == 8){
178 dest[sample_total_saved-1] = sample;
179 data.numbits = sample_total_saved << 3;//Get the return value correct
180 if(sample_total_saved >= bufsize) break;
181 }
182 else{
183 pushBit(&data, sample & 0x80);
184 if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
185 if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
186 if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
187 if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
188 if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
189 if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
190 //Not needed, 8bps is covered above
191 //if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
192 if((data.numbits >> 3) +1 >= bufsize) break;
193 }
194 }
195 }
196
197 if(!silent)
198 {
199 Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
200 Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
201 dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
202 }
203 return data.numbits;
204}
205/**
206 * @brief Does sample acquisition, ignoring the config values set in the sample_config.
207 * This method is typically used by tag-specific readers who just wants to read the samples
208 * the normal way
209 * @param trigger_threshold
210 * @param silent
211 * @return number of bits sampled
212 */
213uint32_t DoAcquisition_default(int trigger_threshold, bool silent)
214{
215 return DoAcquisition(1,8,0,trigger_threshold,silent);
216}
217uint32_t DoAcquisition_config( bool silent)
218{
219 return DoAcquisition(config.decimation
220 ,config.bits_per_sample
221 ,config.averaging
222 ,config.trigger_threshold
223 ,silent);
224}
225
226uint32_t ReadLF(bool activeField, bool silent)
227{
228 if (!silent) printConfig();
229 LFSetupFPGAForADC(config.divisor, activeField);
230 // Now call the acquisition routine
231 return DoAcquisition_config(silent);
232}
233
234/**
235* Initializes the FPGA for reader-mode (field on), and acquires the samples.
236* @return number of bits sampled
237**/
238uint32_t SampleLF(bool printCfg)
239{
240 return ReadLF(true, printCfg);
241}
242/**
243* Initializes the FPGA for snoop-mode (field off), and acquires the samples.
244* @return number of bits sampled
245**/
246uint32_t SnoopLF() {
247 return ReadLF(false, true);
248}
249
250/**
251* acquisition of T55x7 LF signal. Similart to other LF, but adjusted with @marshmellows thresholds
252* the data is collected in BigBuf.
253**/
254void doT55x7Acquisition(size_t sample_size) {
255
256 #define T55xx_READ_UPPER_THRESHOLD 128+60 // 60 grph
257 #define T55xx_READ_LOWER_THRESHOLD 128-60 // -60 grph
258 #define T55xx_READ_TOL 5
259
260 uint8_t *dest = BigBuf_get_addr();
261 uint16_t bufsize = BigBuf_max_traceLen();
262
263 if ( bufsize > sample_size )
264 bufsize = sample_size;
265
266 uint16_t i = 0;
267 bool startFound = false;
268 bool highFound = false;
269 bool lowFound = false;
270 uint8_t curSample = 0;
271 uint8_t lastSample = 0;
272 uint16_t skipCnt = 0;
273 while(!BUTTON_PRESS() && !usb_poll_validate_length() && skipCnt < 1000 && (i < bufsize) ) {
274 WDT_HIT();
275 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
276 AT91C_BASE_SSC->SSC_THR = 0x43;
277 LED_D_ON();
278 }
279 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
280 curSample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
281 LED_D_OFF();
282
283 // skip until the first high sample above threshold
284 if (!startFound && curSample > T55xx_READ_UPPER_THRESHOLD) {
285 //if (curSample > lastSample)
286 // lastSample = curSample;
287 highFound = true;
288 } else if (!highFound) {
289 skipCnt++;
290 continue;
291 }
292 // skip until the first Low sample below threshold
293 if (!startFound && curSample < T55xx_READ_LOWER_THRESHOLD) {
294 //if (curSample > lastSample)
295 lastSample = curSample;
296 lowFound = true;
297 } else if (!lowFound) {
298 skipCnt++;
299 continue;
300 }
301
302
303 // skip until first high samples begin to change
304 if (startFound || curSample > T55xx_READ_LOWER_THRESHOLD+T55xx_READ_TOL){
305 // if just found start - recover last sample
306 if (!startFound) {
307 dest[i++] = lastSample;
308 startFound = true;
309 }
310 // collect samples
311 dest[i++] = curSample;
312 }
313 }
314 }
315}
316
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