+//-----------------------------------------------------------------------------
+// This code is licensed to you under the terms of the GNU GPL, version 2 or,
+// at your option, any later version. See the LICENSE.txt file for the text of
+// the license.
+//-----------------------------------------------------------------------------
+// Miscellaneous routines for low frequency sampling.
+//-----------------------------------------------------------------------------
+
+#include "proxmark3.h"
+#include "apps.h"
+#include "util.h"
+#include "string.h"
+
+#include "lfsampling.h"
+
+sample_config config = { 1, 8, 1, 88, 0 } ;
+
+void printConfig()
+{
+ 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);
+}
+
+
+/**
+ * Called from the USB-handler to set the sampling configuration
+ * The sampling config is used for std reading and snooping.
+ *
+ * Other functions may read samples and ignore the sampling config,
+ * such as functions to read the UID from a prox tag or similar.
+ *
+ * Values set to '0' implies no change (except for averaging)
+ * @brief setSamplingConfig
+ * @param sc
+ */
+void setSamplingConfig(sample_config *sc)
+{
+ 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;
+
+ config.averaging= sc->averaging;
+ if(config.bits_per_sample > 8) config.bits_per_sample = 8;
+ if(config.decimation < 1) config.decimation = 1;
+
+ printConfig();
+}
+
+sample_config* getSamplingConfig()
+{
+ return &config;
+}
+
+typedef struct {
+ uint8_t * buffer;
+ uint32_t numbits;
+ uint32_t position;
+} BitstreamOut;
+
+
+/**
+ * @brief Pushes bit onto the stream
+ * @param stream
+ * @param bit
+ */
+void pushBit( BitstreamOut* stream, uint8_t bit)
+{
+ int bytepos = stream->position >> 3; // divide by 8
+ int bitpos = stream->position & 7;
+ *(stream->buffer+bytepos) |= (bit > 0) << (7 - bitpos);
+ stream->position++;
+ stream->numbits++;
+}
+
+/**
+* Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
+* if not already loaded, sets divisor and starts up the antenna.
+* @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
+* 0 or 95 ==> 125 KHz
+*
+**/
+void LFSetupFPGAForADC(int divisor, bool lf_field)
+{
+ 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
+ else
+ FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
+
+ FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
+
+ // Connect the A/D to the peak-detected low-frequency path.
+ SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
+ // Give it a bit of time for the resonant antenna to settle.
+ SpinDelay(50);
+ // Now set up the SSC to get the ADC samples that are now streaming at us.
+ FpgaSetupSsc();
+}
+
+
+/**
+ * Does the sample acquisition. If threshold is specified, the actual sampling
+ * is not commenced until the threshold has been reached.
+ * This method implements decimation and quantization in order to
+ * be able to provide longer sample traces.
+ * Uses the following global settings:
+ * @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
+ * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
+ * @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
+ * value that will be used is the average value of the three samples.
+ * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
+ * to -1 to ignore threshold.
+ * @param silent - is true, now outputs are made. If false, dbprints the status
+ * @return the number of bits occupied by the samples.
+ */
+
+uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold,bool silent)
+{
+ //.
+ uint8_t *dest = (uint8_t *)BigBuf;
+ int bufsize = BIGBUF_SIZE;
+ memset(dest, 0, bufsize);
+
+ if(bits_per_sample < 1) bits_per_sample = 1;
+ if(bits_per_sample > 8) bits_per_sample = 8;
+
+ if(decimation < 1) decimation = 1;
+
+ // Use a bit stream to handle the output
+ BitstreamOut data = { dest , 0, 0};
+ int sample_counter = 0;
+ uint8_t sample = 0;
+ //If we want to do averaging
+ uint32_t sample_sum =0 ;
+ uint32_t sample_total_numbers =0 ;
+ uint32_t sample_total_saved =0 ;
+
+ while(!BUTTON_PRESS()) {
+ WDT_HIT();
+ if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
+ AT91C_BASE_SSC->SSC_THR = 0x43;
+ LED_D_ON();
+ }
+ if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
+ sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
+ LED_D_OFF();
+ if (trigger_threshold > 0 && sample < trigger_threshold)
+ continue;
+
+ trigger_threshold = 0;
+ sample_total_numbers++;
+
+ if(averaging)
+ {
+ sample_sum += sample;
+ }
+ //Check decimation
+ if(decimation > 1)
+ {
+ sample_counter++;
+ if(sample_counter < decimation) continue;
+ sample_counter = 0;
+ }
+ //Averaging
+ if(averaging && decimation > 1) {
+ sample = sample_sum / decimation;
+ sample_sum =0;
+ }
+ //Store the sample
+ 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;
+ }
+ 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);
+ //Not needed, 8bps is covered above
+ //if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
+ if((data.numbits >> 3) +1 >= bufsize) break;
+ }
+ }
+ }
+
+ if(!silent)
+ {
+ Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
+ 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]);
+ }
+ return data.numbits;
+}
+/**
+ * @brief Does sample acquisition, ignoring the config values set in the sample_config.
+ * This method is typically used by tag-specific readers who just wants to read the samples
+ * the normal way
+ * @param trigger_threshold
+ * @param silent
+ * @return number of bits sampled
+ */
+uint32_t DoAcquisition_default(int trigger_threshold, bool silent)
+{
+ return DoAcquisition(1,8,0,trigger_threshold,silent);
+}
+uint32_t DoAcquisition_config( bool silent)
+{
+ return DoAcquisition(config.decimation
+ ,config.bits_per_sample
+ ,config.averaging
+ ,config.trigger_threshold
+ ,silent);
+}
+
+uint32_t ReadLF(bool activeField)
+{
+ printConfig();
+ LFSetupFPGAForADC(config.divisor, activeField);
+ // Now call the acquisition routine
+ return DoAcquisition_config(false);
+}
+
+/**
+* Initializes the FPGA for reader-mode (field on), and acquires the samples.
+* @return number of bits sampled
+**/
+uint32_t SampleLF()
+{
+ return ReadLF(true);
+}
+/**
+* Initializes the FPGA for snoop-mode (field off), and acquires the samples.
+* @return number of bits sampled
+**/
+
+uint32_t SnoopLF()
+{
+ return ReadLF(false);
+}
projects / proxmark3-svn / commitdiff