X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/proxmark3-svn/blobdiff_plain/15491b2d7398eac88f2a83cab88fc771da4ced6c..1f78a4d305cf7cab4682973bc00c6d391de777d6:/armsrc/lfsampling.c diff --git a/armsrc/lfsampling.c b/armsrc/lfsampling.c new file mode 100644 index 00000000..348549ef --- /dev/null +++ b/armsrc/lfsampling.c @@ -0,0 +1,252 @@ +//----------------------------------------------------------------------------- +// 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 = BigBuf_get_addr(); + int bufsize = BigBuf_max_traceLen(); + + 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); +}