cvs.zerfleddert.de Git - proxmark3-svn/blob

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 //-----------------------------------------------------------------------------

9 #include "proxmark3.h"

10 #include "apps.h"

11 #include "util.h"

12 #include "string.h"

14 #include "lfsampling.h"

 sample_config config = { 1, 8, 1, 88, 0 } ;

18 void printConfig()

19 {

20 Dbprintf("Sampling config: ");

         Dbprintf("  [q] divisor:           %d ", config.divisor);

         Dbprintf("  [b] bps:               %d ", config.bits_per_sample);

         Dbprintf("  [d] decimation:        %d ", config.decimation);

         Dbprintf("  [a] averaging:         %d ", config.averaging);

         Dbprintf("  [t] trigger threshold: %d ", config.trigger_threshold);

26 }

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 */

 void setSamplingConfig(sample_config *sc)

41 {

         if(sc->divisor != 0) config.divisor = sc->divisor;

         if(sc->bits_per_sample!= 0) config.bits_per_sample= sc->bits_per_sample;

         if(sc->decimation!= 0) config.decimation= sc->decimation;

         if(sc->trigger_threshold != -1) config.trigger_threshold= sc->trigger_threshold;

47 config.averaging= sc->averaging;

         if(config.bits_per_sample > 8)  config.bits_per_sample = 8;

         if(config.decimation < 1)       config.decimation = 1;

51 printConfig();

52 }

54 sample_config* getSamplingConfig()

55 {

56 return &config;

57 }

59 typedef struct {

60 uint8_t * buffer;

61 uint32_t numbits;

62 uint32_t position;

63 } BitstreamOut;

66 /**

67 * @brief Pushes bit onto the stream

68 * @param stream

69 * @param bit

70 */

 void pushBit( BitstreamOut* stream, uint8_t bit)

72 {

         int bytepos = stream->position >> 3; // divide by 8

         int bitpos = stream->position & 7;

         *(stream->buffer+bytepos) |= (bit > 0) <<  (7 - bitpos);

76 stream->position++;

77 stream->numbits++;

78 }

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 **/

 void LFSetupFPGAForADC(int divisor, bool lf_field)

88 {

89 FpgaDownloadAndGo(FPGA_BITSTREAM_LF);

         if ( (divisor == 1) || (divisor < 0) || (divisor > 255) )

                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz

         else if (divisor == 0)

                 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz

94 else

95 FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);

         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.

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 /**

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.

122 */

123

 uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold,bool silent)

125 {

126 //.

         uint8_t *dest = BigBuf_get_addr();

128 int bufsize = BigBuf_max_traceLen();

129

         memset(dest, 0, bufsize);

131

         if(bits_per_sample < 1) bits_per_sample = 1;

         if(bits_per_sample > 8) bits_per_sample = 8;

134

         if(decimation < 1) decimation = 1;

136

137 // Use a bit stream to handle the output

         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

146 while(!BUTTON_PRESS()) {

147 WDT_HIT();

                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {

149 AT91C_BASE_SSC->SSC_THR = 0x43;

150 LED_D_ON();

151 }

                 if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {

                         sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;

154 LED_D_OFF();

                         if (trigger_threshold > 0 && sample < trigger_threshold)

156 continue;

157

158 trigger_threshold = 0;

159 sample_total_numbers++;

160

161 if(averaging)

162 {

163 sample_sum += sample;

164 }

165 //Check decimation

                         if(decimation > 1)

167 {

168 sample_counter++;

                                 if(sample_counter < decimation) continue;

170 sample_counter = 0;

171 }

172 //Averaging

                         if(averaging && decimation > 1) {

174 sample = sample_sum / decimation;

175 sample_sum =0;

176 }

177 //Store the sample

178 sample_total_saved ++;

                         if(bits_per_sample == 8){

                                 dest[sample_total_saved-1] = sample;

                                 data.numbits = sample_total_saved << 3;//Get the return value correct

                                 if(sample_total_saved >= bufsize) break;

183 }

184 else{

                                 pushBit(&data, sample & 0x80);

                                 if(bits_per_sample > 1) pushBit(&data, sample & 0x40);

                                 if(bits_per_sample > 2) pushBit(&data, sample & 0x20);

                                 if(bits_per_sample > 3) pushBit(&data, sample & 0x10);

                                 if(bits_per_sample > 4) pushBit(&data, sample & 0x08);

                                 if(bits_per_sample > 5) pushBit(&data, sample & 0x04);

                                 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);

                                 if((data.numbits >> 3) +1  >= bufsize) break;

195 }

196 }

197 }

198

199 if(!silent)

200 {

                 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 ...",

                                         dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);

204 }

205 return data.numbits;

206 }

207 /**

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

210 * the normal way

211 * @param trigger_threshold

212 * @param silent

213 * @return number of bits sampled

214 */

 uint32_t DoAcquisition_default(int trigger_threshold, bool silent)

216 {

         return DoAcquisition(1,8,0,trigger_threshold,silent);

218 }

 uint32_t DoAcquisition_config( bool silent)

220 {

221 return DoAcquisition(config.decimation

222 ,config.bits_per_sample

223 ,config.averaging

224 ,config.trigger_threshold

225 ,silent);

226 }

227

 uint32_t ReadLF(bool activeField)

229 {

230 printConfig();

         LFSetupFPGAForADC(config.divisor, activeField);

232 // Now call the acquisition routine

         return DoAcquisition_config(false);

234 }

235

236 /**

237 * Initializes the FPGA for reader-mode (field on), and acquires the samples.

238 * @return number of bits sampled

239 **/

240 uint32_t SampleLF()

241 {

         return ReadLF(true);

243 }

244 /**

245 * Initializes the FPGA for snoop-mode (field off), and acquires the samples.

246 * @return number of bits sampled

247 **/

248

249 uint32_t SnoopLF()

250 {

         return ReadLF(false);

252 }