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git.zerfleddert.de Git - proxmark3-svn/blob - armsrc/lfsampling.c
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
5 //-----------------------------------------------------------------------------
6 // Miscellaneous routines for low frequency sampling.
7 //-----------------------------------------------------------------------------
14 #include "lfsampling.h"
16 sample_config config
= { 1, 8, 1, 88, 0 } ;
20 Dbprintf("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
);
30 * Called from the USB-handler to set the sampling configuration
31 * The sampling config is used for std reading and snooping.
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.
36 * Values set to '0' implies no change (except for averaging)
37 * @brief setSamplingConfig
40 void setSamplingConfig(sample_config
*sc
)
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
;
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;
54 sample_config
* getSamplingConfig()
67 * @brief Pushes bit onto the stream
71 void pushBit( BitstreamOut
* stream
, uint8_t bit
)
73 int bytepos
= stream
->position
>> 3; // divide by 8
74 int bitpos
= stream
->position
& 7;
75 *(stream
->buffer
+bytepos
) |= (bit
> 0) << (7 - bitpos
);
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
87 void LFSetupFPGAForADC(int divisor
, bool lf_field
)
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
95 FpgaSendCommand(FPGA_CMD_SET_DIVISOR
, divisor
);
97 FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC
| (lf_field
? FPGA_LF_ADC_READER_FIELD
: 0));
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.
103 // Now set up the SSC to get the ADC samples that are now streaming at us.
109 * Does the sample acquisition. If threshold is specified, the actual sampling
110 * is not commenced until the threshold has been reached.
111 * This method implements decimation and quantization in order to
112 * be able to provide longer sample traces.
113 * Uses the following global settings:
114 * @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
115 * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
116 * @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
117 * value that will be used is the average value of the three samples.
118 * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
119 * to -1 to ignore threshold.
120 * @param silent - is true, now outputs are made. If false, dbprints the status
121 * @return the number of bits occupied by the samples.
124 uint32_t DoAcquisition(uint8_t decimation
, uint32_t bits_per_sample
, bool averaging
, int trigger_threshold
,bool silent
)
127 uint8_t *dest
= BigBuf_get_addr();
128 int bufsize
= BigBuf_max_traceLen();
130 memset(dest
, 0, bufsize
);
132 if(bits_per_sample
< 1) bits_per_sample
= 1;
133 if(bits_per_sample
> 8) bits_per_sample
= 8;
135 if(decimation
< 1) decimation
= 1;
137 // Use a bit stream to handle the output
138 BitstreamOut data
= { dest
, 0, 0};
139 int sample_counter
= 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 ;
146 while(!BUTTON_PRESS()) {
148 if (AT91C_BASE_SSC
->SSC_SR
& AT91C_SSC_TXRDY
) {
149 AT91C_BASE_SSC
->SSC_THR
= 0x43;
152 if (AT91C_BASE_SSC
->SSC_SR
& AT91C_SSC_RXRDY
) {
153 sample
= (uint8_t)AT91C_BASE_SSC
->SSC_RHR
;
155 if (trigger_threshold
> 0 && sample
< trigger_threshold
)
158 trigger_threshold
= 0;
159 sample_total_numbers
++;
163 sample_sum
+= sample
;
169 if(sample_counter
< decimation
) continue;
173 if(averaging
&& decimation
> 1) {
174 sample
= sample_sum
/ decimation
;
178 sample_total_saved
++;
179 if(bits_per_sample
== 8){
180 dest
[sample_total_saved
-1] = sample
;
181 data
.numbits
= sample_total_saved
<< 3;//Get the return value correct
182 if(sample_total_saved
>= bufsize
) break;
185 pushBit(&data
, sample
& 0x80);
186 if(bits_per_sample
> 1) pushBit(&data
, sample
& 0x40);
187 if(bits_per_sample
> 2) pushBit(&data
, sample
& 0x20);
188 if(bits_per_sample
> 3) pushBit(&data
, sample
& 0x10);
189 if(bits_per_sample
> 4) pushBit(&data
, sample
& 0x08);
190 if(bits_per_sample
> 5) pushBit(&data
, sample
& 0x04);
191 if(bits_per_sample
> 6) pushBit(&data
, sample
& 0x02);
192 //Not needed, 8bps is covered above
193 //if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
194 if((data
.numbits
>> 3) +1 >= bufsize
) break;
201 Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved
, sample_total_numbers
,bits_per_sample
);
202 Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
203 dest
[0], dest
[1], dest
[2], dest
[3], dest
[4], dest
[5], dest
[6], dest
[7]);
208 * @brief Does sample acquisition, ignoring the config values set in the sample_config.
209 * This method is typically used by tag-specific readers who just wants to read the samples
211 * @param trigger_threshold
213 * @return number of bits sampled
215 uint32_t DoAcquisition_default(int trigger_threshold
, bool silent
)
217 return DoAcquisition(1,8,0,trigger_threshold
,silent
);
219 uint32_t DoAcquisition_config( bool silent
)
221 return DoAcquisition(config
.decimation
222 ,config
.bits_per_sample
224 ,config
.trigger_threshold
228 uint32_t ReadLF(bool activeField
)
231 LFSetupFPGAForADC(config
.divisor
, activeField
);
232 // Now call the acquisition routine
233 return DoAcquisition_config(false);
237 * Initializes the FPGA for reader-mode (field on), and acquires the samples.
238 * @return number of bits sampled
245 * Initializes the FPGA for snoop-mode (field off), and acquires the samples.
246 * @return number of bits sampled
251 return ReadLF(false);