//-----------------------------------------------------------------------------
// 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 "lfsampling.h"
#include "proxmark3_arm.h"
#include "BigBuf.h"
#include "fpgaloader.h"
#include "ticks.h"
#include "dbprint.h"
#include "util.h"
#include "lfdemod.h"
#include "string.h" // memset
/*
Default LF config is set to:
decimation = 1 (we keep 1 out of 1 samples)
bits_per_sample = 8
averaging = YES
divisor = 95 (125kHz)
trigger_threshold = 0
samples_to_skip = 0
verbose = YES
*/
sample_config config = { 1, 8, 1, LF_DIVISOR_125, 0, 0, 1} ;
void printConfig() {
uint32_t d = config.divisor;
DbpString(_BLUE_("LF Sampling config"));
Dbprintf(" [q] divisor.............%d ( "_GREEN_("%d.%02d kHz")")", d, 12000 / (d + 1), ((1200000 + (d + 1) / 2) / (d + 1)) - ((12000 / (d + 1)) * 100));
Dbprintf(" [b] bits per sample.....%d", config.bits_per_sample);
Dbprintf(" [d] decimation..........%d", config.decimation);
Dbprintf(" [a] averaging...........%s", (config.averaging) ? "Yes" : "No");
Dbprintf(" [t] trigger threshold...%d", config.trigger_threshold);
Dbprintf(" [s] samples to skip.....%d ", config.samples_to_skip);
}
/**
* Called from the USB-handler to set the sampling configuration
* The sampling config is used for standard reading and sniffing.
*
* 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 '-1' implies no change
* @brief setSamplingConfig
* @param sc
*/
void setSamplingConfig(sample_config *sc) {
// decimation (1-8) how many bits of adc sample value to save
if (sc->decimation > 0 && sc->decimation < 8)
config.decimation = sc->decimation;
// bits per sample (1-8)
if (sc->bits_per_sample > 0 && sc->bits_per_sample < 8)
config.bits_per_sample = sc->bits_per_sample;
//
if (sc->averaging > -1)
config.averaging = (sc->averaging > 0) ? 1 : 0;
// Frequency divisor (19 - 255)
if (sc->divisor > 18 && sc->divisor < 256)
config.divisor = sc->divisor;
// Start saving samples when adc value larger than trigger_threshold
if (sc->trigger_threshold > -1)
config.trigger_threshold = sc->trigger_threshold;
// Skip n adc samples before saving
if (sc->samples_to_skip > -1)
config.samples_to_skip = sc->samples_to_skip;
if (sc->verbose)
printConfig();
}
sample_config *getSamplingConfig() {
return &config;
}
/**
* @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) &= ~(1 << (7 - bitpos));
*(stream->buffer + bytepos) |= (bit > 0) << (7 - bitpos);
stream->position++;
stream->numbits++;
}
// Holds bit packed struct of samples.
BitstreamOut data = {0, 0, 0};
// internal struct to keep track of samples gathered
sampling_t samples = {0, 0, 0, 0};
void initSampleBuffer(uint32_t *sample_size) {
initSampleBufferEx(sample_size, false);
}
void initSampleBufferEx(uint32_t *sample_size, bool use_malloc) {
BigBuf_free();
// We can't erase the buffer now, it would drastically delay the acquisition
if (use_malloc) {
if (sample_size == NULL || *sample_size == 0 ) {
*sample_size = BigBuf_max_traceLen();
data.buffer = BigBuf_get_addr();
} else {
*sample_size = MIN(*sample_size, BigBuf_max_traceLen());
data.buffer = BigBuf_malloc(*sample_size);
}
} else {
if (sample_size == NULL || *sample_size == 0 ) {
*sample_size = BigBuf_max_traceLen();
}
data.buffer = BigBuf_get_addr();
}
//
samples.dec_counter = 0;
samples.sum = 0;
samples.counter = 0;
samples.total_saved = 0;
}
uint32_t getSampleCounter() {
return samples.total_saved;
}
void logSampleSimple(uint8_t sample) {
logSample(sample, config.decimation, config.bits_per_sample, config.averaging);
}
void logSample(uint8_t sample, uint8_t decimation, uint8_t bits_per_sample, bool avg) {
if (!data.buffer) return;
if (bits_per_sample == 0) bits_per_sample = 1;
if (bits_per_sample > 8) bits_per_sample = 8;
if (decimation == 0) decimation = 1;
// keep track of total gather samples regardless how many was discarded.
samples.counter++;
if (avg) {
samples.sum += sample;
}
// check decimation
if (decimation > 1) {
samples.dec_counter++;
if (samples.dec_counter < decimation) return;
samples.dec_counter = 0;
}
// averaging
if (avg && decimation > 1) {
sample = samples.sum / decimation;
samples.sum = 0;
}
// store the sample
samples.total_saved++;
if (bits_per_sample == 8) {
data.buffer[samples.total_saved - 1] = sample;
// add number of bits.
data.numbits = samples.total_saved << 3;
} 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);
}
}
/**
* 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 reader_field) {
FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
if ((divisor == 1) || (divisor < 0) || (divisor > 255))
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, LF_DIVISOR_134); //~134kHz
else if (divisor == 0)
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, LF_DIVISOR_125); //125kHz
else
FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_READER | (reader_field ? FPGA_LF_ADC_READER_FIELD : 0));
// Connect the A/D to the peak-detected low-frequency path.
SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
// 50ms for the resonant antenna to settle.
if (reader_field)
SpinDelay(50);
// Now set up the SSC to get the ADC samples that are now streaming at us.
FpgaSetupSsc();
// start a 1.5ticks is 1us
StartTicks();
}
/**
* 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 verbose - is true, dbprints the status, else no outputs
* @return the number of bits occupied by the samples.
*/
uint32_t DoAcquisition(uint8_t decimation, uint8_t bits_per_sample, bool avg, int16_t trigger_threshold,
bool verbose, uint32_t sample_size, uint32_t cancel_after, int32_t samples_to_skip) {
initSampleBuffer(&sample_size);
uint32_t cancel_counter = 0;
int16_t checked = 0;
while (!BUTTON_PRESS()) {
// only every 1000th times, in order to save time when collecting samples.
if (checked == 1000) {
if (data_available()) {
checked = -1;
break;
} else {
checked = 0;
}
}
++checked;
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) {
volatile uint8_t sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
// Testpoint 8 (TP8) can be used to trigger oscilliscope
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))) {
if (cancel_after > 0) {
cancel_counter++;
if (cancel_after == cancel_counter)
break;
}
continue;
}
trigger_threshold = 0;
if (samples_to_skip > 0) {
samples_to_skip--;
continue;
}
logSample(sample, decimation, bits_per_sample, avg);
if (samples.total_saved >= sample_size) break;
}
}
if (checked == -1 && verbose) {
Dbprintf("lf sampling aborted");
}
if (verbose) {
Dbprintf("Done, saved " _YELLOW_("%d")"out of " _YELLOW_("%d")"seen samples at " _YELLOW_("%d")"bits/sample", samples.total_saved, samples.counter, bits_per_sample);
}
// Ensure that DC offset removal and noise check is performed for any device-side processing
removeSignalOffset(data.buffer, samples.total_saved);
computeSignalProperties(data.buffer, samples.total_saved);
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 verbose
* @return number of bits sampled
*/
uint32_t DoAcquisition_default(int trigger_threshold, bool verbose) {
return DoAcquisition(1, 8, 0, trigger_threshold, verbose, 0, 0, 0);
}
uint32_t DoAcquisition_config(bool verbose, uint32_t sample_size) {
return DoAcquisition(config.decimation
, config.bits_per_sample
, config.averaging
, config.trigger_threshold
, verbose
, sample_size
, 0
, config.samples_to_skip);
}
uint32_t DoPartialAcquisition(int trigger_threshold, bool verbose, uint32_t sample_size, uint32_t cancel_after) {
return DoAcquisition(1, 8, 0, trigger_threshold, verbose, sample_size, cancel_after, 0);
}
uint32_t ReadLF(bool reader_field, bool verbose, uint32_t sample_size) {
if (verbose)
printConfig();
LFSetupFPGAForADC(config.divisor, reader_field);
uint32_t ret = DoAcquisition_config(verbose, sample_size);
FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
return ret;
}
/**
* Initializes the FPGA for reader-mode (field on), and acquires the samples.
* @return number of bits sampled
**/
uint32_t SampleLF(bool verbose, uint32_t sample_size) {
BigBuf_Clear_ext(false);
return ReadLF(true, verbose, sample_size);
}
/**
* Initializes the FPGA for sniffer-mode (field off), and acquires the samples.
* @return number of bits sampled
**/
uint32_t SniffLF() {
BigBuf_Clear_ext(false);
return ReadLF(false, true, 0);
}
/**
* acquisition of T55x7 LF signal. Similar 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;
uint8_t lastSample = 0;
uint16_t i = 0, skipCnt = 0;
bool startFound = false;
bool highFound = false;
bool lowFound = false;
uint16_t checker = 0;
while (skipCnt < 1000 && (i < bufsize)) {
if (checker == 1000) {
if (BUTTON_PRESS() || data_available())
break;
else
checker = 0;
} else {
++checker;
}
WDT_HIT();
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
LED_D_ON();
}
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
volatile uint8_t sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
LED_D_OFF();
// skip until the first high sample above threshold
if (!startFound && sample > T55xx_READ_UPPER_THRESHOLD) {
highFound = true;
} else if (!highFound) {
skipCnt++;
continue;
}
// skip until the first low sample below threshold
if (!startFound && sample < T55xx_READ_LOWER_THRESHOLD) {
lastSample = sample;
lowFound = true;
} else if (!lowFound) {
skipCnt++;
continue;
}
// skip until first high samples begin to change
if (startFound || sample > 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++] = sample;
}
}
}
}
/**
* acquisition of Cotag LF signal. Similart to other LF, since the Cotag has such long datarate RF/384
* and is Manchester?, we directly gather the manchester data into bigbuff
**/
#define COTAG_T1 384
#define COTAG_T2 (COTAG_T1>>1)
#define COTAG_ONE_THRESHOLD 128+10
#define COTAG_ZERO_THRESHOLD 128-10
#ifndef COTAG_BITS
#define COTAG_BITS 264
#endif
void doCotagAcquisition(size_t sample_size) {
uint8_t *dest = BigBuf_get_addr();
uint16_t bufsize = BigBuf_max_traceLen();
if (bufsize > sample_size)
bufsize = sample_size;
dest[0] = 0;
uint8_t firsthigh = 0, firstlow = 0;
uint16_t i = 0;
uint16_t noise_counter = 0;
uint16_t checker = 0;
while ((i < bufsize) && (noise_counter < (COTAG_T1 << 1))) {
if (checker == 1000) {
if (BUTTON_PRESS() || data_available())
break;
else
checker = 0;
} else {
++checker;
}
WDT_HIT();
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
LED_D_ON();
}
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
volatile uint8_t sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
// find first peak
if (!firsthigh) {
if (sample < COTAG_ONE_THRESHOLD) {
noise_counter++;
continue;
}
noise_counter = 0;
firsthigh = 1;
}
if (!firstlow) {
if (sample > COTAG_ZERO_THRESHOLD) {
noise_counter++;
continue;
}
noise_counter = 0;
firstlow = 1;
}
++i;
if (sample > COTAG_ONE_THRESHOLD)
dest[i] = 255;
else if (sample < COTAG_ZERO_THRESHOLD)
dest[i] = 0;
else
dest[i] = dest[i - 1];
}
}
// Ensure that DC offset removal and noise check is performed for any device-side processing
removeSignalOffset(dest, bufsize);
computeSignalProperties(dest, bufsize);
}
uint32_t doCotagAcquisitionManchester() {
uint8_t *dest = BigBuf_get_addr();
uint16_t bufsize = BigBuf_max_traceLen();
if (bufsize > COTAG_BITS)
bufsize = COTAG_BITS;
dest[0] = 0;
uint8_t firsthigh = 0, firstlow = 0;
uint16_t sample_counter = 0, period = 0;
uint8_t curr = 0, prev = 0;
uint16_t noise_counter = 0;
uint16_t checker = 0;
while ((sample_counter < bufsize) && (noise_counter < (COTAG_T1 << 1))) {
if (checker == 1000) {
if (BUTTON_PRESS() || data_available())
break;
else
checker = 0;
} else {
++checker;
}
WDT_HIT();
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
LED_D_ON();
}
if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
volatile uint8_t sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
// find first peak
if (!firsthigh) {
if (sample < COTAG_ONE_THRESHOLD) {
noise_counter++;
continue;
}
noise_counter = 0;
firsthigh = 1;
}
if (!firstlow) {
if (sample > COTAG_ZERO_THRESHOLD) {
noise_counter++;
continue;
}
noise_counter = 0;
firstlow = 1;
}
// set sample 255, 0, or previous
if (sample > COTAG_ONE_THRESHOLD) {
prev = curr;
curr = 1;
} else if (sample < COTAG_ZERO_THRESHOLD) {
prev = curr;
curr = 0;
} else {
curr = prev;
}
// full T1 periods,
if (period > 0) {
--period;
continue;
}
dest[sample_counter] = curr;
++sample_counter;
period = COTAG_T1;
}
}
return sample_counter;
}