mirror of
https://github.com/RfidResearchGroup/proxmark3.git
synced 2024-09-20 23:36:31 +08:00
316 lines
9.7 KiB
C
316 lines
9.7 KiB
C
//-----------------------------------------------------------------------------
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// This code is licensed to you under the terms of the GNU GPL, version 2 or,
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// at your option, any later version. See the LICENSE.txt file for the text of
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// the license.
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//-----------------------------------------------------------------------------
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// Miscellaneous routines for low frequency sampling.
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//-----------------------------------------------------------------------------
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#include "proxmark3.h"
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#include "apps.h"
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#include "util.h"
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#include "string.h"
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#include "usb_cdc.h" // for usb_poll_validate_length
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#include "lfsampling.h"
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sample_config config = { 1, 8, 1, 95, 0 } ;
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void printConfig()
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{
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Dbprintf("LF Sampling config: ");
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Dbprintf(" [q] divisor: %d ", config.divisor);
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Dbprintf(" [b] bps: %d ", config.bits_per_sample);
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Dbprintf(" [d] decimation: %d ", config.decimation);
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Dbprintf(" [a] averaging: %d ", config.averaging);
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Dbprintf(" [t] trigger threshold: %d ", config.trigger_threshold);
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}
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/**
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* Called from the USB-handler to set the sampling configuration
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* The sampling config is used for std reading and snooping.
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*
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* Other functions may read samples and ignore the sampling config,
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* such as functions to read the UID from a prox tag or similar.
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*
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* Values set to '0' implies no change (except for averaging)
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* @brief setSamplingConfig
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* @param sc
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*/
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void setSamplingConfig(sample_config *sc)
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{
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if(sc->divisor != 0) config.divisor = sc->divisor;
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if(sc->bits_per_sample != 0) config.bits_per_sample = sc->bits_per_sample;
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if(sc->decimation != 0) config.decimation = sc->decimation;
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if(sc->trigger_threshold != -1) config.trigger_threshold = sc->trigger_threshold;
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config.averaging = sc->averaging;
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if(config.bits_per_sample > 8) config.bits_per_sample = 8;
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if(config.decimation < 1) config.decimation = 1;
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printConfig();
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}
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sample_config* getSamplingConfig()
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{
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return &config;
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}
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typedef struct {
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uint8_t * buffer;
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uint32_t numbits;
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uint32_t position;
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} BitstreamOut;
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/**
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* @brief Pushes bit onto the stream
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* @param stream
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* @param bit
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*/
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void pushBit( BitstreamOut* stream, uint8_t bit)
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{
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int bytepos = stream->position >> 3; // divide by 8
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int bitpos = stream->position & 7;
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*(stream->buffer+bytepos) |= (bit > 0) << (7 - bitpos);
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stream->position++;
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stream->numbits++;
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}
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/**
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* Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
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* if not already loaded, sets divisor and starts up the antenna.
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* @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
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* 0 or 95 ==> 125 KHz
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*
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**/
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void LFSetupFPGAForADC(int divisor, bool lf_field)
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{
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FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
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if ( (divisor == 1) || (divisor < 0) || (divisor > 255) )
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FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
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else if (divisor == 0)
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FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
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else
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FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
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FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC | (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
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// Connect the A/D to the peak-detected low-frequency path.
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SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
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// Give it a bit of time for the resonant antenna to settle.
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SpinDelay(50);
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// Now set up the SSC to get the ADC samples that are now streaming at us.
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FpgaSetupSsc();
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}
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/**
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* Does the sample acquisition. If threshold is specified, the actual sampling
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* is not commenced until the threshold has been reached.
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* This method implements decimation and quantization in order to
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* be able to provide longer sample traces.
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* Uses the following global settings:
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* @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
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* @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
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* @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
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* value that will be used is the average value of the three samples.
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* @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
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* to -1 to ignore threshold.
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* @param silent - is true, now outputs are made. If false, dbprints the status
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* @return the number of bits occupied by the samples.
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*/
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uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold,bool silent)
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{
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//bigbuf, to hold the aquired raw data signal
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uint8_t *dest = BigBuf_get_addr();
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uint16_t bufsize = BigBuf_max_traceLen();
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//BigBuf_Clear_ext(false); //creates issues with cmdread (marshmellow)
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if(bits_per_sample < 1) bits_per_sample = 1;
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if(bits_per_sample > 8) bits_per_sample = 8;
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if(decimation < 1) decimation = 1;
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// Use a bit stream to handle the output
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BitstreamOut data = { dest , 0, 0};
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int sample_counter = 0;
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uint8_t sample = 0;
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//If we want to do averaging
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uint32_t sample_sum =0 ;
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uint32_t sample_total_numbers =0 ;
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uint32_t sample_total_saved =0 ;
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while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
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WDT_HIT();
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if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
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AT91C_BASE_SSC->SSC_THR = 0x43;
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LED_D_ON();
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}
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if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
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sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
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LED_D_OFF();
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// threshold either high or low values 128 = center 0. if trigger = 178
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if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-trigger_threshold))) //
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continue;
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trigger_threshold = 0;
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sample_total_numbers++;
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if(averaging)
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{
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sample_sum += sample;
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}
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//Check decimation
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if(decimation > 1)
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{
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sample_counter++;
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if(sample_counter < decimation) continue;
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sample_counter = 0;
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}
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//Averaging
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if(averaging && decimation > 1) {
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sample = sample_sum / decimation;
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sample_sum =0;
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}
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//Store the sample
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sample_total_saved ++;
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if(bits_per_sample == 8){
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dest[sample_total_saved-1] = sample;
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data.numbits = sample_total_saved << 3;//Get the return value correct
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if(sample_total_saved >= bufsize) break;
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}
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else{
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pushBit(&data, sample & 0x80);
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if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
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if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
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if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
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if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
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if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
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if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
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//Not needed, 8bps is covered above
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//if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
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if((data.numbits >> 3) +1 >= bufsize) break;
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}
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}
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}
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if(!silent)
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{
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Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
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Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
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dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
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}
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return data.numbits;
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}
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/**
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* @brief Does sample acquisition, ignoring the config values set in the sample_config.
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* This method is typically used by tag-specific readers who just wants to read the samples
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* the normal way
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* @param trigger_threshold
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* @param silent
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* @return number of bits sampled
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*/
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uint32_t DoAcquisition_default(int trigger_threshold, bool silent)
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{
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return DoAcquisition(1,8,0,trigger_threshold,silent);
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}
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uint32_t DoAcquisition_config( bool silent)
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{
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return DoAcquisition(config.decimation
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,config.bits_per_sample
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,config.averaging
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,config.trigger_threshold
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,silent);
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}
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uint32_t ReadLF(bool activeField, bool silent)
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{
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if (!silent) printConfig();
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LFSetupFPGAForADC(config.divisor, activeField);
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// Now call the acquisition routine
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return DoAcquisition_config(silent);
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}
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/**
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* Initializes the FPGA for reader-mode (field on), and acquires the samples.
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* @return number of bits sampled
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**/
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uint32_t SampleLF(bool printCfg)
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{
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return ReadLF(true, printCfg);
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}
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/**
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* Initializes the FPGA for snoop-mode (field off), and acquires the samples.
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* @return number of bits sampled
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**/
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uint32_t SnoopLF() {
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return ReadLF(false, true);
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}
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/**
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* acquisition of T55x7 LF signal. Similart to other LF, but adjusted with @marshmellows thresholds
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* the data is collected in BigBuf.
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**/
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void doT55x7Acquisition(size_t sample_size) {
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#define T55xx_READ_UPPER_THRESHOLD 128+60 // 60 grph
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#define T55xx_READ_LOWER_THRESHOLD 128-60 // -60 grph
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#define T55xx_READ_TOL 5
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uint8_t *dest = BigBuf_get_addr();
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uint16_t bufsize = BigBuf_max_traceLen();
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if ( bufsize > sample_size )
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bufsize = sample_size;
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uint16_t i = 0;
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bool startFound = false;
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bool highFound = false;
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bool lowFound = false;
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uint8_t curSample = 0;
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uint8_t lastSample = 0;
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uint16_t skipCnt = 0;
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while(!BUTTON_PRESS() && !usb_poll_validate_length() && skipCnt < 1000 && (i < bufsize) ) {
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WDT_HIT();
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if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
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AT91C_BASE_SSC->SSC_THR = 0x43;
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LED_D_ON();
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}
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if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
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curSample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
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LED_D_OFF();
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// skip until the first high sample above threshold
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if (!startFound && curSample > T55xx_READ_UPPER_THRESHOLD) {
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//if (curSample > lastSample)
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// lastSample = curSample;
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highFound = true;
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} else if (!highFound) {
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skipCnt++;
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continue;
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}
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// skip until the first Low sample below threshold
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if (!startFound && curSample < T55xx_READ_LOWER_THRESHOLD) {
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//if (curSample > lastSample)
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lastSample = curSample;
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lowFound = true;
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} else if (!lowFound) {
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skipCnt++;
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continue;
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}
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// skip until first high samples begin to change
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if (startFound || curSample > T55xx_READ_LOWER_THRESHOLD+T55xx_READ_TOL){
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// if just found start - recover last sample
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if (!startFound) {
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dest[i++] = lastSample;
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startFound = true;
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}
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// collect samples
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dest[i++] = curSample;
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}
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}
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}
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}
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