- int bytepos = stream->position >> 3; // divide by 8
- int bitpos = stream->position & 7;
- *(stream->buffer+bytepos) |= (bit & 1) << (7 - bitpos);
- stream->position++;
- stream->numbits++;
-}
-/**
- * @brief Does LF sample acquisition, this method implements decimation and quantization in order to
- * be able to provide longer sample traces.
- * @param decimation - how much should the signal be decimated. A decimation of 1 means every sample, 2 means
- * every other sample, etc.
- * @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
- * @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
- * to -1 to ignore threshold.
- * @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.
- * @return the number of bits occupied by the samples.
- */
-uint8_t DoAcquisition(int decimation, int bits_per_sample, int trigger_threshold, bool averaging)
-{
- //A decimation of 2 means we keep every 2nd sample
- //A decimation of 3 means we keep 1 in 3 samples.
- //A quantization of 1 means one bit is discarded from the sample (division by 2).
- 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;
-
- // 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 ;
-
- for(;;) {
- 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;
- if (trigger_threshold != -1 && sample < trigger_threshold)
- continue;
- sample_total_numbers++;
-
- LED_D_OFF();
- trigger_threshold = -1;
- sample_counter++;
- sample_sum += sample;
- //Check decimation
- if(sample_counter < decimation) continue;
- //Averaging
- if(averaging) sample = sample_sum / decimation;
-
- sample_counter = 0;
- sample_sum =0;
- sample_total_saved ++;
- 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);
- if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
-
- if((data.numbits >> 3) +1 >= bufsize) break;
- }
- }
- Dbprintf("Done, saved %l out of %l seen samples.",sample_total_saved, sample_total_numbers);
-
- return data.numbits;
-}
-
-
-/**
-* Does the sample acquisition. If threshold is specified, the actual sampling
-* is not commenced until the threshold has been reached.
-* @param trigger_threshold - the threshold
-* @param silent - is true, now outputs are made. If false, dbprints the status
-*/
-void DoAcquisition125k_internal(int trigger_threshold,bool silent)
-{
- uint8_t *dest = (uint8_t *)BigBuf;
- int n = sizeof(BigBuf);
- int i;
-
- memset(dest, 0, n);
- i = 0;
- for(;;) {
- 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) {
- dest[i] = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
- LED_D_OFF();
- if (trigger_threshold != -1 && dest[i] < trigger_threshold)
- continue;
- else
- trigger_threshold = -1;
- if (++i >= n) break;
- }
- }
- if(!silent)
- {
- 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]);
-
- }
-}
-/**
-* Perform sample aquisition.
-*/
-void DoAcquisition125k(int trigger_threshold)
-{
- DoAcquisition125k_internal(trigger_threshold, false);
-}
-
-/**
-* 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();
-}
-/**
-* Initializes the FPGA, and acquires the samples.
-**/
-void AcquireRawAdcSamples125k(int divisor)
-{
- LFSetupFPGAForADC(divisor, true);
- // Now call the acquisition routine
- DoAcquisition125k_internal(-1,false);
-}
-/**
-* Initializes the FPGA for snoop-mode, and acquires the samples.
-**/
-
-void SnoopLFRawAdcSamples(int divisor, int trigger_threshold)
-{
- LFSetupFPGAForADC(divisor, false);
- DoAcquisition125k(trigger_threshold);
-}
-
-void ModThenAcquireRawAdcSamples125k(int delay_off, int period_0, int period_1, uint8_t *command)
-{
-
- /* Make sure the tag is reset */
- FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
- FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
- SpinDelay(2500);
-
projects / proxmark3-svn / blobdiff