document iclass raw key changes

[proxmark3-svn] / armsrc / lfsampling.c

//-----------------------------------------------------------------------------
// 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 "usb_cdc.h" // for usb_poll_validate_length
#include "lfsampling.h"

sample_config config = { 1, 8, 1, 95, 0 } ;

void printConfig()
{
        Dbprintf("LF 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();
                        // threshold either high or low values 128 = center 0.  if trigger = 178 
                        if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-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, bool silent)
{
        if (!silent) printConfig();
        LFSetupFPGAForADC(config.divisor, activeField);
        // Now call the acquisition routine
        return DoAcquisition_config(silent);
}

/**
* Initializes the FPGA for reader-mode (field on), and acquires the samples.
* @return number of bits sampled
**/
uint32_t SampleLF(bool printCfg)
{
        return ReadLF(true, printCfg);
}
/**
* Initializes the FPGA for snoop-mode (field off), and acquires the samples.
* @return number of bits sampled
**/

uint32_t SnoopLF()
{
        return ReadLF(false, true);
}

/**
* acquisition of T55x7 LF signal. Similart to other LF, but adjusted with @marshmellows thresholds
* the data is collected in BigBuf.
**/
void doT55x7Acquisition(size_t sample_size) {

        #define T55xx_READ_UPPER_THRESHOLD 128+60  // 60 grph
        #define T55xx_READ_LOWER_THRESHOLD 128-60  // -60 grph
        #define T55xx_READ_TOL   5

        uint8_t *dest = BigBuf_get_addr();
        uint16_t bufsize = BigBuf_max_traceLen();
        
        if ( bufsize > sample_size )
                bufsize = sample_size;

        uint16_t i = 0;
        bool startFound = false;
        bool highFound = false;
        bool lowFound = false;
        uint8_t curSample = 0;
        uint8_t lastSample = 0;
        uint16_t skipCnt = 0;
        while(!BUTTON_PRESS() && !usb_poll_validate_length() && skipCnt<1000 && i<bufsize ) {
                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) {
                        curSample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
                        LED_D_OFF();

                        // skip until the first high sample above threshold
                        if (!startFound && curSample > T55xx_READ_UPPER_THRESHOLD) {
                                //if (curSample > lastSample) 
                                //      lastSample = curSample;
                                highFound = true;
                        } else if (!highFound) {
                                skipCnt++;
                                continue;
                        }
                        // skip until the first Low sample below threshold
                        if (!startFound && curSample < T55xx_READ_LOWER_THRESHOLD) {
                                //if (curSample > lastSample) 
                                lastSample = curSample;
                                lowFound = true;
                        } else if (!lowFound) {
                                skipCnt++;
                                continue;
                        }


                        // skip until first high samples begin to change
                        if (startFound || curSample > T55xx_READ_LOWER_THRESHOLD+T55xx_READ_TOL){
                                // if just found start - recover last sample
                                if (!startFound) {
                                        dest[i++] = lastSample;
                                        startFound = true;
                                }
                                // collect samples
                                dest[i++] = curSample;
                        }
                }
        }
}