[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 "lfsampling.h"
#include "usb_cdc.h"	// for usb_poll_validate_length
//#include "ticks.h"		// for StartTicks

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, int bufsize)
{
	//.
	uint8_t *dest = BigBuf_get_addr();
	bufsize = (bufsize > 0 && bufsize < BigBuf_max_traceLen()) ? bufsize : BigBuf_max_traceLen();

	//memset(dest, 0, bufsize); //creates issues with cmdread (marshmellow)

	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() && !usb_poll_validate_length() ) {
		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,0);
}
uint32_t DoAcquisition_config( bool silent)
{
	return DoAcquisition(config.decimation
				  ,config.bits_per_sample
				  ,config.averaging
				  ,config.trigger_threshold
				  ,silent
				  ,0);
}

uint32_t DoPartialAcquisition(int trigger_threshold, bool silent, int sample_size) {
	return DoAcquisition(1,8,0,trigger_threshold,silent,sample_size);
}

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)
{
	uint32_t ret = ReadLF(true, printCfg);
	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	return ret;
}
/**
* Initializes the FPGA for snoop-mode (field off), and acquires the samples.
* @return number of bits sampled
**/

uint32_t SnoopLF()
{
	uint32_t ret = ReadLF(false, true);
	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	return ret;
}

/**
* 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+30
#define COTAG_ZERO_THRESHOLD 128-30
#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 sample = 0, firsthigh = 0, firstlow = 0; 
	uint16_t i = 0;

	while (!BUTTON_PRESS() && !usb_poll_validate_length() && (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) {
			sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
			LED_D_OFF();
		
			// find first peak
			if ( !firsthigh ) {
				if (sample < COTAG_ONE_THRESHOLD) 
					continue;
				firsthigh = 1;
			}
			if ( !firstlow ){
				if (sample > COTAG_ZERO_THRESHOLD )
					continue;
				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];
		}
	}
}

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 sample = 0, firsthigh = 0, firstlow = 0; 
	uint16_t sample_counter = 0, period = 0;
	uint8_t curr = 0, prev = 0;

	while (!BUTTON_PRESS() && !usb_poll_validate_length() && (sample_counter < 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) {
			sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
			LED_D_OFF();

			// find first peak
			if ( !firsthigh ) {
				if (sample < COTAG_ONE_THRESHOLD) 
					continue;
				firsthigh = 1;
			}

			if ( !firstlow ){
				if (sample > COTAG_ZERO_THRESHOLD )
					continue;
				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;
}
Commit	Line	Data
31abe49f MHS	1	//-----------------------------------------------------------------------------
	2	// This code is licensed to you under the terms of the GNU GPL, version 2 or,
	3	// at your option, any later version. See the LICENSE.txt file for the text of
	4	// the license.
	5	//-----------------------------------------------------------------------------
	6	// Miscellaneous routines for low frequency sampling.
	7	//-----------------------------------------------------------------------------
	8
	9	#include "proxmark3.h"
	10	#include "apps.h"
	11	#include "util.h"
	12	#include "string.h"
31abe49f	13	#include "lfsampling.h"
e04475c4	14	#include "usb_cdc.h" // for usb_poll_validate_length
e04475c4	15	//#include "ticks.h" // for StartTicks
10a8875c	16
0cd2a41a	17	sample_config config = { 1, 8, 1, 95, 0 } ;
31abe49f MHS	18
	19	void printConfig()
	20	{
e2012d1b	21	Dbprintf("LF Sampling config: ");
31abe49f MHS	22	Dbprintf(" [q] divisor: %d ", config.divisor);
	23	Dbprintf(" [b] bps: %d ", config.bits_per_sample);
	24	Dbprintf(" [d] decimation: %d ", config.decimation);
	25	Dbprintf(" [a] averaging: %d ", config.averaging);
	26	Dbprintf(" [t] trigger threshold: %d ", config.trigger_threshold);
	27	}
	28
	29
	30	/**
	31	* Called from the USB-handler to set the sampling configuration
	32	* The sampling config is used for std reading and snooping.
	33	*
	34	* Other functions may read samples and ignore the sampling config,
	35	* such as functions to read the UID from a prox tag or similar.
	36	*
	37	* Values set to '0' implies no change (except for averaging)
	38	* @brief setSamplingConfig
	39	* @param sc
	40	*/
	41	void setSamplingConfig(sample_config *sc)
	42	{
	43	if(sc->divisor != 0) config.divisor = sc->divisor;
	44	if(sc->bits_per_sample!= 0) config.bits_per_sample= sc->bits_per_sample;
	45	if(sc->decimation!= 0) config.decimation= sc->decimation;
	46	if(sc->trigger_threshold != -1) config.trigger_threshold= sc->trigger_threshold;
	47
	48	config.averaging= sc->averaging;
	49	if(config.bits_per_sample > 8) config.bits_per_sample = 8;
	50	if(config.decimation < 1) config.decimation = 1;
	51
	52	printConfig();
	53	}
	54
	55	sample_config* getSamplingConfig()
	56	{
	57	return &config;
	58	}
10a8875c	59
31abe49f MHS	60	typedef struct {
	61	uint8_t * buffer;
	62	uint32_t numbits;
	63	uint32_t position;
	64	} BitstreamOut;
	65
31abe49f MHS	66	/**
	67	* @brief Pushes bit onto the stream
	68	* @param stream
	69	* @param bit
	70	*/
10a8875c	71	void pushBit( BitstreamOut* stream, uint8_t bit)
31abe49f MHS	72	{
	73	int bytepos = stream->position >> 3; // divide by 8
	74	int bitpos = stream->position & 7;
	75	*(stream->buffer+bytepos) \|= (bit > 0) << (7 - bitpos);
	76	stream->position++;
	77	stream->numbits++;
	78	}
10a8875c	79
31abe49f MHS	80	/**
	81	* Setup the FPGA to listen for samples. This method downloads the FPGA bitstream
	82	* if not already loaded, sets divisor and starts up the antenna.
	83	* @param divisor : 1, 88> 255 or negative ==> 134.8 KHz
	84	* 0 or 95 ==> 125 KHz
	85	*
	86	**/
	87	void LFSetupFPGAForADC(int divisor, bool lf_field)
	88	{
	89	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
	90	if ( (divisor == 1) \|\| (divisor < 0) \|\| (divisor > 255) )
	91	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 88); //134.8Khz
	92	else if (divisor == 0)
	93	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
	94	else
	95	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, divisor);
	96
	97	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_ADC \| (lf_field ? FPGA_LF_ADC_READER_FIELD : 0));
	98
	99	// Connect the A/D to the peak-detected low-frequency path.
	100	SetAdcMuxFor(GPIO_MUXSEL_LOPKD);
	101	// Give it a bit of time for the resonant antenna to settle.
	102	SpinDelay(50);
	103	// Now set up the SSC to get the ADC samples that are now streaming at us.
	104	FpgaSetupSsc();
	105	}
	106
31abe49f MHS	107	/**
	108	* Does the sample acquisition. If threshold is specified, the actual sampling
	109	* is not commenced until the threshold has been reached.
	110	* This method implements decimation and quantization in order to
	111	* be able to provide longer sample traces.
	112	* Uses the following global settings:
	113	* @param decimation - how much should the signal be decimated. A decimation of N means we keep 1 in N samples, etc.
	114	* @param bits_per_sample - bits per sample. Max 8, min 1 bit per sample.
	115	* @param averaging If set to true, decimation will use averaging, so that if e.g. decimation is 3, the sample
	116	* value that will be used is the average value of the three samples.
	117	* @param trigger_threshold - a threshold. The sampling won't commence until this threshold has been reached. Set
	118	* to -1 to ignore threshold.
	119	* @param silent - is true, now outputs are made. If false, dbprints the status
	120	* @return the number of bits occupied by the samples.
	121	*/
a37228c8	122	uint32_t DoAcquisition(uint8_t decimation, uint32_t bits_per_sample, bool averaging, int trigger_threshold, bool silent, int bufsize)
31abe49f MHS	123	{
31abe49f MHS	124	//.
0644d5e3	125	uint8_t *dest = BigBuf_get_addr();
a37228c8	126	bufsize = (bufsize > 0 && bufsize < BigBuf_max_traceLen()) ? bufsize : BigBuf_max_traceLen();
0644d5e3	127
3cec7061	128	//memset(dest, 0, bufsize); //creates issues with cmdread (marshmellow)
31abe49f MHS	129
	130	if(bits_per_sample < 1) bits_per_sample = 1;
	131	if(bits_per_sample > 8) bits_per_sample = 8;
	132
	133	if(decimation < 1) decimation = 1;
	134
	135	// Use a bit stream to handle the output
	136	BitstreamOut data = { dest , 0, 0};
	137	int sample_counter = 0;
	138	uint8_t sample = 0;
	139	//If we want to do averaging
	140	uint32_t sample_sum =0 ;
	141	uint32_t sample_total_numbers =0 ;
	142	uint32_t sample_total_saved =0 ;
	143
e04475c4	144	while(!BUTTON_PRESS() && !usb_poll_validate_length() ) {
31abe49f MHS	145	WDT_HIT();
	146	if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
	147	AT91C_BASE_SSC->SSC_THR = 0x43;
	148	LED_D_ON();
	149	}
	150	if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
	151	sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
	152	LED_D_OFF();
b29d55f2	153	// threshold either high or low values 128 = center 0. if trigger = 178
b29d55f2	154	if ((trigger_threshold > 0) && (sample < (trigger_threshold+128)) && (sample > (128-trigger_threshold))) //
31abe49f	155	continue;
b29d55f2	156
31abe49f MHS	157	trigger_threshold = 0;
	158	sample_total_numbers++;
	159
	160	if(averaging)
	161	{
	162	sample_sum += sample;
	163	}
	164	//Check decimation
	165	if(decimation > 1)
	166	{
	167	sample_counter++;
	168	if(sample_counter < decimation) continue;
	169	sample_counter = 0;
	170	}
	171	//Averaging
	172	if(averaging && decimation > 1) {
	173	sample = sample_sum / decimation;
	174	sample_sum =0;
	175	}
	176	//Store the sample
	177	sample_total_saved ++;
	178	if(bits_per_sample == 8){
	179	dest[sample_total_saved-1] = sample;
	180	data.numbits = sample_total_saved << 3;//Get the return value correct
	181	if(sample_total_saved >= bufsize) break;
	182	}
	183	else{
	184	pushBit(&data, sample & 0x80);
	185	if(bits_per_sample > 1) pushBit(&data, sample & 0x40);
	186	if(bits_per_sample > 2) pushBit(&data, sample & 0x20);
	187	if(bits_per_sample > 3) pushBit(&data, sample & 0x10);
	188	if(bits_per_sample > 4) pushBit(&data, sample & 0x08);
	189	if(bits_per_sample > 5) pushBit(&data, sample & 0x04);
	190	if(bits_per_sample > 6) pushBit(&data, sample & 0x02);
	191	//Not needed, 8bps is covered above
	192	//if(bits_per_sample > 7) pushBit(&data, sample & 0x01);
	193	if((data.numbits >> 3) +1 >= bufsize) break;
	194	}
	195	}
	196	}
	197
	198	if(!silent)
	199	{
	200	Dbprintf("Done, saved %d out of %d seen samples at %d bits/sample",sample_total_saved, sample_total_numbers,bits_per_sample);
	201	Dbprintf("buffer samples: %02x %02x %02x %02x %02x %02x %02x %02x ...",
	202	dest[0], dest[1], dest[2], dest[3], dest[4], dest[5], dest[6], dest[7]);
	203	}
	204	return data.numbits;
	205	}
	206	/**
	207	* @brief Does sample acquisition, ignoring the config values set in the sample_config.
	208	* This method is typically used by tag-specific readers who just wants to read the samples
	209	* the normal way
	210	* @param trigger_threshold
	211	* @param silent
	212	* @return number of bits sampled
	213	*/
	214	uint32_t DoAcquisition_default(int trigger_threshold, bool silent)
	215	{
a37228c8	216	return DoAcquisition(1,8,0,trigger_threshold,silent,0);
31abe49f MHS	217	}
	218	uint32_t DoAcquisition_config( bool silent)
	219	{
	220	return DoAcquisition(config.decimation
	221	,config.bits_per_sample
	222	,config.averaging
	223	,config.trigger_threshold
a37228c8	224	,silent
	225	,0);
	226	}
	227
	228	uint32_t DoPartialAcquisition(int trigger_threshold, bool silent, int sample_size) {
	229	return DoAcquisition(1,8,0,trigger_threshold,silent,sample_size);
31abe49f MHS	230	}
31abe49f MHS	231
1fbf8956	232	uint32_t ReadLF(bool activeField, bool silent)
31abe49f	233	{
1fbf8956	234	if (!silent) printConfig();
31abe49f MHS	235	LFSetupFPGAForADC(config.divisor, activeField);
31abe49f MHS	236	// Now call the acquisition routine
1fbf8956	237	return DoAcquisition_config(silent);
31abe49f MHS	238	}
	239
	240	/**
	241	* Initializes the FPGA for reader-mode (field on), and acquires the samples.
	242	* @return number of bits sampled
	243	**/
1fbf8956	244	uint32_t SampleLF(bool printCfg)
31abe49f	245	{
e04475c4	246	uint32_t ret = ReadLF(true, printCfg);
	247	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	248	return ret;
31abe49f MHS	249	}
	250	/**
	251	* Initializes the FPGA for snoop-mode (field off), and acquires the samples.
	252	* @return number of bits sampled
	253	**/
	254
	255	uint32_t SnoopLF()
	256	{
e04475c4	257	uint32_t ret = ReadLF(false, true);
	258	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	259	return ret;
31abe49f	260	}
7cfc777b	261
e04475c4	262	/**
	263	* acquisition of Cotag LF signal. Similart to other LF, since the Cotag has such long datarate RF/384
	264	* and is Manchester?, we directly gather the manchester data into bigbuff
	265	**/
	266	#define COTAG_T1 384
	267	#define COTAG_T2 (COTAG_T1>>1)
	268	#define COTAG_ONE_THRESHOLD 128+30
	269	#define COTAG_ZERO_THRESHOLD 128-30
	270	#ifndef COTAG_BITS
	271	#define COTAG_BITS 264
	272	#endif
	273	void doCotagAcquisition(size_t sample_size) {
	274
	275	uint8_t *dest = BigBuf_get_addr();
	276	uint16_t bufsize = BigBuf_max_traceLen();
	277
	278	if ( bufsize > sample_size )
	279	bufsize = sample_size;
	280
	281	dest[0] = 0;
	282	uint8_t sample = 0, firsthigh = 0, firstlow = 0;
	283	uint16_t i = 0;
	284
	285	while (!BUTTON_PRESS() && !usb_poll_validate_length() && (i < bufsize) ) {
	286	WDT_HIT();
	287	if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
	288	AT91C_BASE_SSC->SSC_THR = 0x43;
	289	LED_D_ON();
	290	}
	291
	292	if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
	293	sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
	294	LED_D_OFF();
	295
	296	// find first peak
	297	if ( !firsthigh ) {
	298	if (sample < COTAG_ONE_THRESHOLD)
	299	continue;
	300	firsthigh = 1;
	301	}
	302	if ( !firstlow ){
	303	if (sample > COTAG_ZERO_THRESHOLD )
	304	continue;
	305	firstlow = 1;
	306	}
	307
	308	++i;
	309
	310	if ( sample > COTAG_ONE_THRESHOLD)
	311	dest[i] = 255;
	312	else if ( sample < COTAG_ZERO_THRESHOLD)
	313	dest[i] = 0;
	314	else
	315	dest[i] = dest[i-1];
	316	}
	317	}
	318	}
	319
	320	uint32_t doCotagAcquisitionManchester() {
	321
	322	uint8_t *dest = BigBuf_get_addr();
	323	uint16_t bufsize = BigBuf_max_traceLen();
	324
	325	if ( bufsize > COTAG_BITS )
326	bufsize = COTAG_BITS;
327
328	dest[0] = 0;
329	uint8_t sample = 0, firsthigh = 0, firstlow = 0;
330	uint16_t sample_counter = 0, period = 0;
331	uint8_t curr = 0, prev = 0;
332
333	while (!BUTTON_PRESS() && !usb_poll_validate_length() && (sample_counter < bufsize) ) {
334	WDT_HIT();
335	if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_TXRDY) {
336	AT91C_BASE_SSC->SSC_THR = 0x43;
337	LED_D_ON();
338	}
339
340	if (AT91C_BASE_SSC->SSC_SR & AT91C_SSC_RXRDY) {
341	sample = (uint8_t)AT91C_BASE_SSC->SSC_RHR;
342	LED_D_OFF();
343
344	// find first peak
345	if ( !firsthigh ) {
346	if (sample < COTAG_ONE_THRESHOLD)
347	continue;
348	firsthigh = 1;
349	}
350
351	if ( !firstlow ){
352	if (sample > COTAG_ZERO_THRESHOLD )
353	continue;
354	firstlow = 1;
355	}
356
357	// set sample 255, 0, or previous
358	if ( sample > COTAG_ONE_THRESHOLD){
359	prev = curr;
360	curr = 1;
361	}
362	else if ( sample < COTAG_ZERO_THRESHOLD) {
363	prev = curr;
364	curr = 0;
365	}
366	else {
367	curr = prev;
368	}
369
370	// full T1 periods,
371	if ( period > 0 ) {
372	--period;
373	continue;
374	}
375
376	dest[sample_counter] = curr;
377	++sample_counter;
378	period = COTAG_T1;
379	}
380	}
381	return sample_counter;
382	}