[proxmark3-svn] / armsrc / pcf7931.c

#include "proxmark3.h"
#include "apps.h"
#include "lfsampling.h"
#include "pcf7931.h"
#include "util.h"
#include "string.h"
#include "fpgaloader.h"

#define T0_PCF 8 //period for the pcf7931 in us
#define ALLOC 16

size_t DemodPCF7931(uint8_t **outBlocks) {
	uint8_t bits[256] = {0x00};
	uint8_t blocks[8][16];
	uint8_t *dest = BigBuf_get_addr();

	int GraphTraceLen = BigBuf_max_traceLen();
	if (GraphTraceLen > 18000)
		GraphTraceLen = 18000;

	int i, j, lastval, bitidx, half_switch;
	int clock = 64;
	int tolerance = clock / 8;
	int pmc, block_done;
	int lc, warnings = 0;
	size_t num_blocks = 0;
	int lmin=128, lmax=128;
	uint8_t dir;
	//clear read buffer
	BigBuf_Clear_keep_EM();

	LFSetupFPGAForADC(95, true);
	DoAcquisition_default(0, true);

	lmin = 64;
	lmax = 192;

	i = 2;

	/* Find first local max/min */
	if(dest[1] > dest[0]) {
		while(i < GraphTraceLen) {
			if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
				break;
			i++;
		}
		dir = 0;
	} else {
		while(i < GraphTraceLen) {
			if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
				break;
			i++;
		}
		dir = 1;
	}

	lastval = i++;
	half_switch = 0;
	pmc = 0;
	block_done = 0;

	for (bitidx = 0; i < GraphTraceLen; i++) {
		if ((dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) || (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin)) {
			lc = i - lastval;
			lastval = i;

			// Switch depending on lc length:
			// Tolerance is 1/8 of clock rate (arbitrary)
			if (ABS(lc-clock/4) < tolerance) {
				// 16T0
				if((i - pmc) == lc) { /* 16T0 was previous one */
					/* It's a PMC ! */
					i += (128+127+16+32+33+16)-1;
					lastval = i;
					pmc = 0;
					block_done = 1;
				} else {
					pmc = i;
				}
			} else if (ABS(lc-clock/2) < tolerance) {
				// 32TO
				if((i - pmc) == lc) { /* 16T0 was previous one */
					/* It's a PMC ! */
					i += (128+127+16+32+33)-1;
					lastval = i;
					pmc = 0;
					block_done = 1;
				} else if(half_switch == 1) {
					bits[bitidx++] = 0;
					half_switch = 0;
				}
				else
					half_switch++;
			} else if (ABS(lc-clock) < tolerance) {
				// 64TO
				bits[bitidx++] = 1;
			} else {
				// Error
				if (++warnings > 10) {
					Dbprintf("Error: too many detection errors, aborting.");
					return 0;
				}
			}

			if(block_done == 1) {
				if(bitidx == 128) {
					for(j = 0; j < 16; ++j) {
						blocks[num_blocks][j] =
							128 * bits[j*8 + 7]+
											64 * bits[j*8 + 6] +
							32 * bits[j*8 + 5] +
							16 * bits[j*8 + 4] +
							8 * bits[j*8 + 3] +
							4 * bits[j*8 + 2] +
							2 * bits[j*8 + 1] +
							bits[j*8]
						;
					}
					num_blocks++;
				}
				bitidx = 0;
				block_done = 0;
				half_switch = 0;
			}
			if(i < GraphTraceLen)
				dir = (dest[i-1] > dest[i]) ? 0 : 1;
		}
		if(bitidx==255)
			bitidx=0;
		warnings = 0;
		if(num_blocks == 4) break;
	}
	memcpy(outBlocks, blocks, 16 * num_blocks);
	return num_blocks;
}

bool IsBlock0PCF7931(uint8_t *block) {
	// assuming all RFU bits are set to 0
	// if PAC is enabled password is set to 0
	if (block[7] == 0x01)
	{
		if (!memcmp(block, "\x00\x00\x00\x00\x00\x00\x00", 7) && !memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
			return true;
	}
	else if (block[7] == 0x00)
	{
		if (!memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
			return true;
	}
	return false;
}

bool IsBlock1PCF7931(uint8_t *block) {
	// assuming all RFU bits are set to 0

	uint8_t rb1 = block[14] & 0x80;
	uint8_t rfb = block[14] & 0x7f;
	uint8_t rlb = block[15];

	if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
		// block 1 is sent only if (RLB >= 1 && RFB <= 1) or RB1 enabled
		if(rfb <= rlb && rfb <= 9 && rlb <= 9 && ((rfb <= 1 && rlb >= 1) || rb1))
			return true;

	return false;
}

void ReadPCF7931() {
	int found_blocks = 0; // successfully read blocks
	int max_blocks = 8; // readable blocks
	uint8_t memory_blocks[8][17]; // PCF content

	uint8_t single_blocks[8][17]; // PFC blocks with unknown position
	int single_blocks_cnt = 0;

	size_t n = 0; // transmitted blocks
	uint8_t tmp_blocks[4][16]; // temporary read buffer

	uint8_t found_0_1 = 0; // flag: blocks 0 and 1 were found
	int errors = 0; // error counter
	int tries = 0; // tries counter

	memset(memory_blocks, 0, 8*17*sizeof(uint8_t));
	memset(single_blocks, 0, 8*17*sizeof(uint8_t));

	int i = 0, j = 0;

	do {
		i = 0;

		memset(tmp_blocks, 0, 4*16*sizeof(uint8_t));
		n = DemodPCF7931((uint8_t**)tmp_blocks);
		if(!n)
			++errors;

		// exit if no block is received
		if (errors >= 10 && found_blocks == 0 && single_blocks_cnt == 0) {
			Dbprintf("Error, no tag or bad tag");
			return;
		}

		// exit if too many errors during reading
		if (tries > 50 && (2*errors > tries)) {
			Dbprintf("Error reading the tag");
			Dbprintf("Here is the partial content");
			goto end;
		}

		// our logic breaks if we don't get at least two blocks
		if (n < 2) {
			// skip if all 0s block or no blocks
			if (n == 0 || !memcmp(tmp_blocks[0], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16))
				continue;

			// add block to single blocks list
			if (single_blocks_cnt < max_blocks) {
				for (i = 0; i < single_blocks_cnt; ++i) {
					if (!memcmp(single_blocks[i], tmp_blocks[0], 16)) {
						j = 1;
						break;
					}
				}
				if (j != 1) {
					memcpy(single_blocks[single_blocks_cnt], tmp_blocks[0], 16);
					print_result("got single block", single_blocks[single_blocks_cnt], 16);
					single_blocks_cnt++;
				}
				j = 0;
			}
			++tries;
			continue;
		}

		Dbprintf("(dbg) got %d blocks (%d/%d found) (%d tries, %d errors)", n, found_blocks, (max_blocks == 0 ? found_blocks : max_blocks), tries, errors);
		for (i = 0; i < n; ++i)
		{
			print_result("got consecutive blocks", tmp_blocks[i], 16);
		}

		i = 0;
		if(!found_0_1) {
			while (i < n - 1) {
				if (IsBlock0PCF7931(tmp_blocks[i]) && IsBlock1PCF7931(tmp_blocks[i+1])) {
					found_0_1 = 1;
					memcpy(memory_blocks[0], tmp_blocks[i], 16);
					memcpy(memory_blocks[1], tmp_blocks[i+1], 16);
					memory_blocks[0][ALLOC] = memory_blocks[1][ALLOC] = 1;
					// block 1 tells how many blocks are going to be sent
					max_blocks = MAX((memory_blocks[1][14] & 0x7f), memory_blocks[1][15]) + 1;
					found_blocks = 2;

					Dbprintf("Found blocks 0 and 1. PCF is transmitting %d blocks.", max_blocks);

					// handle the following blocks
					for (j = i + 2; j < n; ++j) {
						memcpy(memory_blocks[found_blocks], tmp_blocks[j], 16);
						memory_blocks[found_blocks][ALLOC] = 1;
						++found_blocks;
					}
					break;
				}
				++i;
			}
		} else {
			// Trying to re-order blocks
			// Look for identical block in memory blocks
			while (i < n-1) {
				// skip all zeroes blocks
				if (memcmp(tmp_blocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
					for (j = 1; j < max_blocks - 1; ++j) {
						if (!memcmp(tmp_blocks[i], memory_blocks[j], 16) && !memory_blocks[j+1][ALLOC]) {
							memcpy(memory_blocks[j+1], tmp_blocks[i+1], 16);
							memory_blocks[j+1][ALLOC] = 1;
							if (++found_blocks >= max_blocks) goto end;
						}
					}
				}
				if (memcmp(tmp_blocks[i+1], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
					for (j = 0; j < max_blocks; ++j) {
						if (!memcmp(tmp_blocks[i+1], memory_blocks[j], 16) && !memory_blocks[(j == 0 ? max_blocks : j) -1][ALLOC]) {
							if (j == 0) {
								memcpy(memory_blocks[max_blocks - 1], tmp_blocks[i], 16);
								memory_blocks[max_blocks - 1][ALLOC] = 1;
							} else {
								memcpy(memory_blocks[j-1], tmp_blocks[i], 16);
								memory_blocks[j-1][ALLOC] = 1;
							}
							if (++found_blocks >= max_blocks) goto end;
						}
					}
				}
				++i;
			}
		}
		++tries;
		if (BUTTON_PRESS()) {
			Dbprintf("Button pressed, stopping.");
			goto end;
		}
	}
	while (found_blocks < max_blocks);

 end:
	Dbprintf("-----------------------------------------");
	Dbprintf("Memory content:");
	Dbprintf("-----------------------------------------");
	for (i = 0; i < max_blocks; ++i) {
		if (memory_blocks[i][ALLOC])
			print_result("Block", memory_blocks[i], 16);
		else
			Dbprintf("<missing block %d>", i);
	}
	Dbprintf("-----------------------------------------");

	if (found_blocks < max_blocks) {
		Dbprintf("-----------------------------------------");
		Dbprintf("Blocks with unknown position:");
		Dbprintf("-----------------------------------------");
		for (i = 0; i < single_blocks_cnt; ++i)
			print_result("Block", single_blocks[i], 16);

		Dbprintf("-----------------------------------------");
	}
	cmd_send(CMD_ACK,0,0,0,0,0);
}

static void RealWritePCF7931(uint8_t *pass, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
	uint32_t tab[1024]={0}; // data times frame
	uint32_t u = 0;
	uint8_t parity = 0;
	bool comp = 0;

	//BUILD OF THE DATA FRAME
	//alimentation of the tag (time for initializing)
	AddPatternPCF7931(init_delay, 0, 8192/2*T0_PCF, tab);
	AddPatternPCF7931(8192/2*T0_PCF + 319*T0_PCF+70, 3*T0_PCF, 29*T0_PCF, tab);
	//password indication bit
	AddBitPCF7931(1, tab, l, p);
	// password (on 56 bits)
	AddBytePCF7931(pass[0], tab, l, p);
	AddBytePCF7931(pass[1], tab, l, p);
	AddBytePCF7931(pass[2], tab, l, p);
	AddBytePCF7931(pass[3], tab, l, p);
	AddBytePCF7931(pass[4], tab, l, p);
	AddBytePCF7931(pass[5], tab, l, p);
	AddBytePCF7931(pass[6], tab, l, p);
	//programming mode (0 or 1)
	AddBitPCF7931(0, tab, l, p);

	//block adress on 6 bits
	for (u = 0; u < 6; ++u) {
		if (address & (1 << u)) {   // bit 1
			 ++parity;
			 AddBitPCF7931(1, tab, l, p);
		} else {                    // bit 0
			 AddBitPCF7931(0, tab, l, p);
		}
	}

	//byte address on 4 bits
	for (u = 0; u < 4; ++u)
	{
		if (byte & (1 << u)) {  // bit 1
			 parity++;
			 AddBitPCF7931(1, tab, l, p);
		}
		else                // bit 0
			 AddBitPCF7931(0, tab, l, p);
	}

	//data on 8 bits
	for (u=0; u<8; u++)
	{
		if (data&(1<<u)) {  // bit 1
			 parity++;
			 AddBitPCF7931(1, tab, l, p);
		}
		else                //bit 0
			 AddBitPCF7931(0, tab, l, p);
	}

	//parity bit
	if ((parity % 2) == 0)
		AddBitPCF7931(0, tab, l, p); //even parity
	else
		AddBitPCF7931(1, tab, l, p);//odd parity

	//time access memory
	AddPatternPCF7931(5120+2680, 0, 0, tab);

	//conversion of the scale time
	for (u = 0; u < 500; ++u)
		tab[u] = (tab[u] * 3) / 2;

	//compennsation of the counter reload
	while (!comp) {
		comp = 1;
		for (u = 0; tab[u] != 0; ++u)
			if(tab[u] > 0xFFFF) {
			  tab[u] -= 0xFFFF;
			  comp = 0;
			}
	}

	SendCmdPCF7931(tab);
}

void BruteForcePCF7931(uint64_t password, uint8_t tries, uint16_t init_delay, int32_t l, int32_t p) {
	uint8_t i = 0;
	uint8_t pass_array[7];

	while (password < 0x00FFFFFFFFFFFFFF) {
		if (BUTTON_PRESS()) {
			Dbprintf("Button pressed, stopping bruteforce ...");
			return;
		}

		num_to_bytes(password, 7, pass_array);

		Dbprintf("Trying: %02x %02x %02x %02x %02x %02x %02x ...",
			pass_array[0],
			pass_array[1],
			pass_array[2],
			pass_array[3],
			pass_array[4],
			pass_array[5],
			pass_array[6]);

		for (i = 0; i < tries; ++i)
			RealWritePCF7931
			(
				pass_array,
				init_delay,
				l,
				p,
				0,
				7,
				0x01
			);

		++password;
	}
}

/* Write on a byte of a PCF7931 tag
 * @param address : address of the block to write
   @param byte : address of the byte to write
	@param data : data to write
 */
void WritePCF7931(uint8_t pass1, uint8_t pass2, uint8_t pass3, uint8_t pass4, uint8_t pass5, uint8_t pass6, uint8_t pass7, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
	Dbprintf("Initialization delay : %d us", init_delay);
	Dbprintf("Offsets : %d us on the low pulses width, %d us on the low pulses positions", l, p);
	Dbprintf("Password (LSB first on each byte): %02x %02x %02x %02x %02x %02x %02x", pass1, pass2, pass3, pass4, pass5, pass6, pass7);
	Dbprintf("Block address : %02x", address);
	Dbprintf("Byte address : %02x", byte);
	Dbprintf("Data : %02x", data);

	uint8_t password[7] = {pass1, pass2, pass3, pass4, pass5, pass6, pass7};

	RealWritePCF7931 (password, init_delay, l, p, address, byte, data);
}


/* Send a trame to a PCF7931 tags
 * @param tab : array of the data frame
 */

void SendCmdPCF7931(uint32_t * tab) {
	uint16_t u=0;
	uint16_t tempo=0;

	Dbprintf("Sending data frame ...");

	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU );

	LED_A_ON();

	// steal this pin from the SSP and use it to control the modulation
	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;

	//initialization of the timer
	AT91C_BASE_PMC->PMC_PCER |= (0x1 << 12) | (0x1 << 13) | (0x1 << 14);
	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE | AT91C_TCB_TC1XC1S_TIOA0 | AT91C_TCB_TC2XC2S_NONE;
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK;  //clock at 48/32 MHz
	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
	AT91C_BASE_TCB->TCB_BCR = 1;

	tempo = AT91C_BASE_TC0->TC_CV;
	for (u = 0; tab[u] !=  0; u += 3) {
		// modulate antenna
		HIGH(GPIO_SSC_DOUT);
		while(tempo !=  tab[u])
			tempo = AT91C_BASE_TC0->TC_CV;

		// stop modulating antenna
		LOW(GPIO_SSC_DOUT);
		while(tempo !=  tab[u+1])
			tempo = AT91C_BASE_TC0->TC_CV;

		// modulate antenna
		HIGH(GPIO_SSC_DOUT);
		while(tempo !=  tab[u+2])
			tempo = AT91C_BASE_TC0->TC_CV;
	}

	LED_A_OFF();
	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	SpinDelay(200);

	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	DbpString("Data frame sent (multiple sends may be needed)");
	LED(0xFFFF, 1000);
}


/* Add a byte for building the data frame of PCF7931 tags
 * @param b : byte to add
 * @param tab : array of the data frame
 * @param l : offset on low pulse width
 * @param p : offset on low pulse positioning
 */
bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p) {
	uint32_t u;
	for (u = 0; u < 8; ++u) {
		if (byte & (1 << u)) {  //bit is 1
			if(AddBitPCF7931(1, tab, l, p)==1)return 1;
		} else { //bit is 0
			if(AddBitPCF7931(0, tab, l, p)==1)return 1;
		}
	}

	return 0;
}

/* Add a bits for building the data frame of PCF7931 tags
 * @param b : bit to add
 * @param tab : array of the data frame
 * @param l : offset on low pulse width
 * @param p : offset on low pulse positioning
 */
bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p) {
	uint8_t u = 0;

	for (u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array

	if (b == 1) {   //add a bit 1
		if (u == 0) tab[u] = 34 * T0_PCF + p;
		else        tab[u] = 34 * T0_PCF + tab[u-1] + p;

		tab[u+1] = 6 * T0_PCF+tab[u] + l;
		tab[u+2] = 88 * T0_PCF+tab[u + 1] - l - p;
		return 0;
	} else {        //add a bit 0

		if (u == 0) tab[u] = 98 * T0_PCF + p;
		else        tab[u] = 98 * T0_PCF + tab[u-1] + p;

		tab[u + 1] = 6 * T0_PCF + tab[u] + l;
		tab[u + 2] = 24 * T0_PCF + tab[u + 1] - l - p;
		return 0;
	}

	return 1;
}

/* Add a custom pattern in the data frame
 * @param a : delay of the first high pulse
 * @param b : delay of the low pulse
 * @param c : delay of the last high pulse
 * @param tab : array of the data frame
 */
bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab) {
	uint32_t u = 0;
	for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array

	if (u == 0) tab[u] = a;
	else        tab[u] = a + tab[u - 1];

	tab[u + 1] = b + tab[u];
	tab[u + 2] = c + tab[u + 1];

	return 0;
}
Commit	Line	Data
d10e08ae	1	#include "proxmark3.h"
	2	#include "apps.h"
	3	#include "lfsampling.h"
	4	#include "pcf7931.h"
b8e461ff	5	#include "util.h"
d10e08ae	6	#include "string.h"
fc52fbd4	7	#include "fpgaloader.h"
d10e08ae	8
	9	#define T0_PCF 8 //period for the pcf7931 in us
	10	#define ALLOC 16
	11
818e15b0 S	12	size_t DemodPCF7931(uint8_t **outBlocks) {
818e15b0 S	13	uint8_t bits[256] = {0x00};
d10e08ae	14	uint8_t blocks[8][16];
818e15b0	15	uint8_t *dest = BigBuf_get_addr();
caaa4293	16
d10e08ae	17	int GraphTraceLen = BigBuf_max_traceLen();
818e15b0	18	if (GraphTraceLen > 18000)
d10e08ae	19	GraphTraceLen = 18000;
caaa4293	20
d10e08ae	21	int i, j, lastval, bitidx, half_switch;
	22	int clock = 64;
	23	int tolerance = clock / 8;
	24	int pmc, block_done;
	25	int lc, warnings = 0;
818e15b0	26	size_t num_blocks = 0;
d10e08ae	27	int lmin=128, lmax=128;
d10e08ae	28	uint8_t dir;
3cec7061	29	//clear read buffer
29b75739	30	BigBuf_Clear_keep_EM();
d10e08ae	31
	32	LFSetupFPGAForADC(95, true);
	33	DoAcquisition_default(0, true);
	34
	35	lmin = 64;
	36	lmax = 192;
	37
	38	i = 2;
	39
	40	/* Find first local max/min */
818e15b0	41	if(dest[1] > dest[0]) {
d10e08ae	42	while(i < GraphTraceLen) {
818e15b0	43	if( !(dest[i] > dest[i-1]) && dest[i] > lmax)
d10e08ae	44	break;
	45	i++;
	46	}
	47	dir = 0;
818e15b0	48	} else {
d10e08ae	49	while(i < GraphTraceLen) {
818e15b0	50	if( !(dest[i] < dest[i-1]) && dest[i] < lmin)
d10e08ae	51	break;
	52	i++;
	53	}
	54	dir = 1;
	55	}
	56
	57	lastval = i++;
	58	half_switch = 0;
	59	pmc = 0;
	60	block_done = 0;
	61
818e15b0 S	62	for (bitidx = 0; i < GraphTraceLen; i++) {
818e15b0 S	63	if ((dest[i-1] > dest[i] && dir == 1 && dest[i] > lmax) \|\| (dest[i-1] < dest[i] && dir == 0 && dest[i] < lmin)) {
d10e08ae	64	lc = i - lastval;
	65	lastval = i;
	66
	67	// Switch depending on lc length:
	68	// Tolerance is 1/8 of clock rate (arbitrary)
cf194819	69	if (ABS(lc-clock/4) < tolerance) {
d10e08ae	70	// 16T0
	71	if((i - pmc) == lc) { /* 16T0 was previous one */
	72	/* It's a PMC ! */
	73	i += (128+127+16+32+33+16)-1;
	74	lastval = i;
	75	pmc = 0;
	76	block_done = 1;
818e15b0	77	} else {
d10e08ae	78	pmc = i;
d10e08ae	79	}
cf194819	80	} else if (ABS(lc-clock/2) < tolerance) {
d10e08ae	81	// 32TO
	82	if((i - pmc) == lc) { /* 16T0 was previous one */
	83	/* It's a PMC ! */
	84	i += (128+127+16+32+33)-1;
	85	lastval = i;
	86	pmc = 0;
	87	block_done = 1;
818e15b0 S	88	} else if(half_switch == 1) {
818e15b0 S	89	bits[bitidx++] = 0;
d10e08ae	90	half_switch = 0;
	91	}
	92	else
	93	half_switch++;
cf194819	94	} else if (ABS(lc-clock) < tolerance) {
d10e08ae	95	// 64TO
818e15b0	96	bits[bitidx++] = 1;
d10e08ae	97	} else {
d10e08ae	98	// Error
818e15b0	99	if (++warnings > 10) {
d10e08ae	100	Dbprintf("Error: too many detection errors, aborting.");
	101	return 0;
	102	}
	103	}
	104
	105	if(block_done == 1) {
	106	if(bitidx == 128) {
818e15b0 S	107	for(j = 0; j < 16; ++j) {
	108	blocks[num_blocks][j] =
	109	128 * bits[j*8 + 7]+
caaa4293	110	64 * bits[j*8 + 6] +
818e15b0 S	111	32 * bits[j*8 + 5] +
	112	16 * bits[j*8 + 4] +
	113	8 * bits[j*8 + 3] +
	114	4 * bits[j*8 + 2] +
	115	2 * bits[j*8 + 1] +
	116	bits[j*8]
	117	;
d10e08ae	118	}
	119	num_blocks++;
	120	}
	121	bitidx = 0;
	122	block_done = 0;
	123	half_switch = 0;
	124	}
	125	if(i < GraphTraceLen)
818e15b0	126	dir = (dest[i-1] > dest[i]) ? 0 : 1;
d10e08ae	127	}
	128	if(bitidx==255)
	129	bitidx=0;
	130	warnings = 0;
	131	if(num_blocks == 4) break;
	132	}
818e15b0	133	memcpy(outBlocks, blocks, 16 * num_blocks);
d10e08ae	134	return num_blocks;
	135	}
	136
818e15b0 S	137	bool IsBlock0PCF7931(uint8_t *block) {
	138	// assuming all RFU bits are set to 0
	139	// if PAC is enabled password is set to 0
	140	if (block[7] == 0x01)
	141	{
	142	if (!memcmp(block, "\x00\x00\x00\x00\x00\x00\x00", 7) && !memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
	143	return true;
	144	}
	145	else if (block[7] == 0x00)
	146	{
	147	if (!memcmp(block+9, "\x00\x00\x00\x00\x00\x00\x00", 7))
	148	return true;
	149	}
	150	return false;
d10e08ae	151	}
d10e08ae	152
818e15b0 S	153	bool IsBlock1PCF7931(uint8_t *block) {
818e15b0 S	154	// assuming all RFU bits are set to 0
cfa9c98d S	155
	156	uint8_t rb1 = block[14] & 0x80;
	157	uint8_t rfb = block[14] & 0x7f;
	158	uint8_t rlb = block[15];
	159
818e15b0	160	if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
cfa9c98d S	161	// block 1 is sent only if (RLB >= 1 && RFB <= 1) or RB1 enabled
cfa9c98d S	162	if(rfb <= rlb && rfb <= 9 && rlb <= 9 && ((rfb <= 1 && rlb >= 1) \|\| rb1))
818e15b0	163	return true;
d10e08ae	164
818e15b0	165	return false;
d10e08ae	166	}
	167
	168	void ReadPCF7931() {
818e15b0	169	int found_blocks = 0; // successfully read blocks
caaa4293	170	int max_blocks = 8; // readable blocks
818e15b0	171	uint8_t memory_blocks[8][17]; // PCF content
caaa4293	172
818e15b0 S	173	uint8_t single_blocks[8][17]; // PFC blocks with unknown position
818e15b0 S	174	int single_blocks_cnt = 0;
d10e08ae	175
caaa4293	176	size_t n = 0; // transmitted blocks
818e15b0	177	uint8_t tmp_blocks[4][16]; // temporary read buffer
caaa4293	178
818e15b0 S	179	uint8_t found_0_1 = 0; // flag: blocks 0 and 1 were found
	180	int errors = 0; // error counter
	181	int tries = 0; // tries counter
caaa4293	182
818e15b0 S	183	memset(memory_blocks, 0, 817sizeof(uint8_t));
818e15b0 S	184	memset(single_blocks, 0, 817sizeof(uint8_t));
caaa4293	185
818e15b0	186	int i = 0, j = 0;
d10e08ae	187
d10e08ae	188	do {
818e15b0	189	i = 0;
caaa4293	190
818e15b0 S	191	memset(tmp_blocks, 0, 416sizeof(uint8_t));
818e15b0 S	192	n = DemodPCF7931((uint8_t**)tmp_blocks);
d10e08ae	193	if(!n)
818e15b0	194	++errors;
caaa4293	195
caaa4293	196	// exit if no block is received
818e15b0	197	if (errors >= 10 && found_blocks == 0 && single_blocks_cnt == 0) {
d10e08ae	198	Dbprintf("Error, no tag or bad tag");
	199	return;
	200	}
cfa9c98d	201
caaa4293	202	// exit if too many errors during reading
818e15b0	203	if (tries > 50 && (2*errors > tries)) {
d10e08ae	204	Dbprintf("Error reading the tag");
	205	Dbprintf("Here is the partial content");
	206	goto end;
	207	}
caaa4293	208
818e15b0 S	209	// our logic breaks if we don't get at least two blocks
818e15b0 S	210	if (n < 2) {
cfa9c98d	211	// skip if all 0s block or no blocks
818e15b0 S	212	if (n == 0 \|\| !memcmp(tmp_blocks[0], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16))
	213	continue;
	214
cfa9c98d	215	// add block to single blocks list
818e15b0 S	216	if (single_blocks_cnt < max_blocks) {
	217	for (i = 0; i < single_blocks_cnt; ++i) {
	218	if (!memcmp(single_blocks[i], tmp_blocks[0], 16)) {
	219	j = 1;
d10e08ae	220	break;
	221	}
	222	}
818e15b0 S	223	if (j != 1) {
818e15b0 S	224	memcpy(single_blocks[single_blocks_cnt], tmp_blocks[0], 16);
cfa9c98d	225	print_result("got single block", single_blocks[single_blocks_cnt], 16);
818e15b0 S	226	single_blocks_cnt++;
	227	}
	228	j = 0;
d10e08ae	229	}
818e15b0 S	230	++tries;
818e15b0 S	231	continue;
caaa4293	232	}
	233
	234	Dbprintf("(dbg) got %d blocks (%d/%d found) (%d tries, %d errors)", n, found_blocks, (max_blocks == 0 ? found_blocks : max_blocks), tries, errors);
cfa9c98d S	235	for (i = 0; i < n; ++i)
	236	{
	237	print_result("got consecutive blocks", tmp_blocks[i], 16);
	238	}
818e15b0 S	239
818e15b0 S	240	i = 0;
caaa4293	241	if(!found_0_1) {
818e15b0 S	242	while (i < n - 1) {
	243	if (IsBlock0PCF7931(tmp_blocks[i]) && IsBlock1PCF7931(tmp_blocks[i+1])) {
	244	found_0_1 = 1;
	245	memcpy(memory_blocks[0], tmp_blocks[i], 16);
	246	memcpy(memory_blocks[1], tmp_blocks[i+1], 16);
	247	memory_blocks[0][ALLOC] = memory_blocks[1][ALLOC] = 1;
	248	// block 1 tells how many blocks are going to be sent
	249	max_blocks = MAX((memory_blocks[1][14] & 0x7f), memory_blocks[1][15]) + 1;
	250	found_blocks = 2;
caaa4293	251
818e15b0	252	Dbprintf("Found blocks 0 and 1. PCF is transmitting %d blocks.", max_blocks);
caaa4293	253
818e15b0 S	254	// handle the following blocks
	255	for (j = i + 2; j < n; ++j) {
	256	memcpy(memory_blocks[found_blocks], tmp_blocks[j], 16);
	257	memory_blocks[found_blocks][ALLOC] = 1;
	258	++found_blocks;
	259	}
	260	break;
	261	}
	262	++i;
	263	}
	264	} else {
	265	// Trying to re-order blocks
	266	// Look for identical block in memory blocks
	267	while (i < n-1) {
	268	// skip all zeroes blocks
	269	if (memcmp(tmp_blocks[i], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
	270	for (j = 1; j < max_blocks - 1; ++j) {
	271	if (!memcmp(tmp_blocks[i], memory_blocks[j], 16) && !memory_blocks[j+1][ALLOC]) {
	272	memcpy(memory_blocks[j+1], tmp_blocks[i+1], 16);
	273	memory_blocks[j+1][ALLOC] = 1;
	274	if (++found_blocks >= max_blocks) goto end;
	275	}
	276	}
	277	}
	278	if (memcmp(tmp_blocks[i+1], "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00", 16)) {
	279	for (j = 0; j < max_blocks; ++j) {
	280	if (!memcmp(tmp_blocks[i+1], memory_blocks[j], 16) && !memory_blocks[(j == 0 ? max_blocks : j) -1][ALLOC]) {
	281	if (j == 0) {
	282	memcpy(memory_blocks[max_blocks - 1], tmp_blocks[i], 16);
	283	memory_blocks[max_blocks - 1][ALLOC] = 1;
	284	} else {
	285	memcpy(memory_blocks[j-1], tmp_blocks[i], 16);
	286	memory_blocks[j-1][ALLOC] = 1;
d10e08ae	287	}
818e15b0	288	if (++found_blocks >= max_blocks) goto end;
d10e08ae	289	}
	290	}
	291	}
818e15b0	292	++i;
d10e08ae	293	}
d10e08ae	294	}
818e15b0 S	295	++tries;
	296	if (BUTTON_PRESS()) {
	297	Dbprintf("Button pressed, stopping.");
	298	goto end;
	299	}
	300	}
cfa9c98d	301	while (found_blocks < max_blocks);
818e15b0	302
d10e08ae	303	end:
	304	Dbprintf("-----------------------------------------");
	305	Dbprintf("Memory content:");
	306	Dbprintf("-----------------------------------------");
818e15b0 S	307	for (i = 0; i < max_blocks; ++i) {
	308	if (memory_blocks[i][ALLOC])
	309	print_result("Block", memory_blocks[i], 16);
d10e08ae	310	else
	311	Dbprintf("<missing block %d>", i);
	312	}
	313	Dbprintf("-----------------------------------------");
caaa4293	314
818e15b0 S	315	if (found_blocks < max_blocks) {
	316	Dbprintf("-----------------------------------------");
	317	Dbprintf("Blocks with unknown position:");
	318	Dbprintf("-----------------------------------------");
	319	for (i = 0; i < single_blocks_cnt; ++i)
	320	print_result("Block", single_blocks[i], 16);
caaa4293	321
818e15b0 S	322	Dbprintf("-----------------------------------------");
818e15b0 S	323	}
7cfc777b	324	cmd_send(CMD_ACK,0,0,0,0,0);
d10e08ae	325	}
d10e08ae	326
818e15b0	327	static void RealWritePCF7931(uint8_t *pass, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
d10e08ae	328	uint32_t tab[1024]={0}; // data times frame
	329	uint32_t u = 0;
	330	uint8_t parity = 0;
	331	bool comp = 0;
	332
	333	//BUILD OF THE DATA FRAME
d10e08ae	334	//alimentation of the tag (time for initializing)
d10e08ae	335	AddPatternPCF7931(init_delay, 0, 8192/2*T0_PCF, tab);
d10e08ae	336	AddPatternPCF7931(8192/2T0_PCF + 319T0_PCF+70, 3T0_PCF, 29T0_PCF, tab);
d10e08ae	337	//password indication bit
d10e08ae	338	AddBitPCF7931(1, tab, l, p);
818e15b0 S	339	// password (on 56 bits)
	340	AddBytePCF7931(pass[0], tab, l, p);
	341	AddBytePCF7931(pass[1], tab, l, p);
	342	AddBytePCF7931(pass[2], tab, l, p);
	343	AddBytePCF7931(pass[3], tab, l, p);
	344	AddBytePCF7931(pass[4], tab, l, p);
	345	AddBytePCF7931(pass[5], tab, l, p);
	346	AddBytePCF7931(pass[6], tab, l, p);
d10e08ae	347	//programming mode (0 or 1)
d10e08ae	348	AddBitPCF7931(0, tab, l, p);
caaa4293	349
d10e08ae	350	//block adress on 6 bits
818e15b0	351	for (u = 0; u < 6; ++u) {
caaa4293	352	if (address & (1 << u)) { // bit 1
818e15b0	353	++parity;
d10e08ae	354	AddBitPCF7931(1, tab, l, p);
caaa4293	355	} else { // bit 0
d10e08ae	356	AddBitPCF7931(0, tab, l, p);
	357	}
	358	}
caaa4293	359
d10e08ae	360	//byte address on 4 bits
818e15b0	361	for (u = 0; u < 4; ++u)
d10e08ae	362	{
caaa4293	363	if (byte & (1 << u)) { // bit 1
d10e08ae	364	parity++;
d10e08ae	365	AddBitPCF7931(1, tab, l, p);
d10e08ae	366	}
caaa4293	367	else // bit 0
818e15b0	368	AddBitPCF7931(0, tab, l, p);
d10e08ae	369	}
caaa4293	370
d10e08ae	371	//data on 8 bits
d10e08ae	372	for (u=0; u<8; u++)
d10e08ae	373	{
caaa4293	374	if (data&(1<<u)) { // bit 1
d10e08ae	375	parity++;
d10e08ae	376	AddBitPCF7931(1, tab, l, p);
caaa4293	377	}
caaa4293	378	else //bit 0
d10e08ae	379	AddBitPCF7931(0, tab, l, p);
d10e08ae	380	}
d10e08ae	381
d10e08ae	382	//parity bit
818e15b0	383	if ((parity % 2) == 0)
caaa4293	384	AddBitPCF7931(0, tab, l, p); //even parity
818e15b0	385	else
d10e08ae	386	AddBitPCF7931(1, tab, l, p);//odd parity
d10e08ae	387
	388	//time access memory
	389	AddPatternPCF7931(5120+2680, 0, 0, tab);
	390
	391	//conversion of the scale time
818e15b0 S	392	for (u = 0; u < 500; ++u)
818e15b0 S	393	tab[u] = (tab[u] * 3) / 2;
d10e08ae	394
d10e08ae	395	//compennsation of the counter reload
818e15b0	396	while (!comp) {
d10e08ae	397	comp = 1;
818e15b0 S	398	for (u = 0; tab[u] != 0; ++u)
818e15b0 S	399	if(tab[u] > 0xFFFF) {
d10e08ae	400	tab[u] -= 0xFFFF;
	401	comp = 0;
	402	}
d10e08ae	403	}
	404
	405	SendCmdPCF7931(tab);
	406	}
	407
818e15b0 S	408	void BruteForcePCF7931(uint64_t password, uint8_t tries, uint16_t init_delay, int32_t l, int32_t p) {
	409	uint8_t i = 0;
	410	uint8_t pass_array[7];
caaa4293	411
818e15b0 S	412	while (password < 0x00FFFFFFFFFFFFFF) {
	413	if (BUTTON_PRESS()) {
	414	Dbprintf("Button pressed, stopping bruteforce ...");
	415	return;
	416	}
caaa4293	417
caaa4293	418	num_to_bytes(password, 7, pass_array);
818e15b0 S	419
	420	Dbprintf("Trying: %02x %02x %02x %02x %02x %02x %02x ...",
	421	pass_array[0],
	422	pass_array[1],
	423	pass_array[2],
	424	pass_array[3],
	425	pass_array[4],
	426	pass_array[5],
	427	pass_array[6]);
caaa4293	428
818e15b0 S	429	for (i = 0; i < tries; ++i)
	430	RealWritePCF7931
	431	(
	432	pass_array,
	433	init_delay,
	434	l,
	435	p,
	436	0,
	437	7,
	438	0x01
	439	);
caaa4293	440
caaa4293	441	++password;
818e15b0 S	442	}
	443	}
	444
	445	/* Write on a byte of a PCF7931 tag
	446	* @param address : address of the block to write
	447	@param byte : address of the byte to write
caaa4293	448	@param data : data to write
818e15b0 S	449	*/
	450	void WritePCF7931(uint8_t pass1, uint8_t pass2, uint8_t pass3, uint8_t pass4, uint8_t pass5, uint8_t pass6, uint8_t pass7, uint16_t init_delay, int32_t l, int32_t p, uint8_t address, uint8_t byte, uint8_t data) {
	451	Dbprintf("Initialization delay : %d us", init_delay);
	452	Dbprintf("Offsets : %d us on the low pulses width, %d us on the low pulses positions", l, p);
	453	Dbprintf("Password (LSB first on each byte): %02x %02x %02x %02x %02x %02x %02x", pass1, pass2, pass3, pass4, pass5, pass6, pass7);
	454	Dbprintf("Block address : %02x", address);
	455	Dbprintf("Byte address : %02x", byte);
	456	Dbprintf("Data : %02x", data);
caaa4293	457
818e15b0	458	uint8_t password[7] = {pass1, pass2, pass3, pass4, pass5, pass6, pass7};
caaa4293	459
818e15b0 S	460	RealWritePCF7931 (password, init_delay, l, p, address, byte, data);
	461	}
	462
d10e08ae	463
	464
	465	/* Send a trame to a PCF7931 tags
	466	* @param tab : array of the data frame
	467	*/
	468
818e15b0	469	void SendCmdPCF7931(uint32_t * tab) {
d10e08ae	470	uint16_t u=0;
	471	uint16_t tempo=0;
	472
818e15b0	473	Dbprintf("Sending data frame ...");
d10e08ae	474
d10e08ae	475	FpgaDownloadAndGo(FPGA_BITSTREAM_LF);
d10e08ae	476	FpgaSendCommand(FPGA_CMD_SET_DIVISOR, 95); //125Khz
d10e08ae	477	FpgaWriteConfWord(FPGA_MAJOR_MODE_LF_PASSTHRU );
	478
	479	LED_A_ON();
	480
	481	// steal this pin from the SSP and use it to control the modulation
	482	AT91C_BASE_PIOA->PIO_PER = GPIO_SSC_DOUT;
	483	AT91C_BASE_PIOA->PIO_OER = GPIO_SSC_DOUT;
	484
	485	//initialization of the timer
	486	AT91C_BASE_PMC->PMC_PCER \|= (0x1 << 12) \| (0x1 << 13) \| (0x1 << 14);
	487	AT91C_BASE_TCB->TCB_BMR = AT91C_TCB_TC0XC0S_NONE \| AT91C_TCB_TC1XC1S_TIOA0 \| AT91C_TCB_TC2XC2S_NONE;
	488	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
	489	AT91C_BASE_TC0->TC_CMR = AT91C_TC_CLKS_TIMER_DIV3_CLOCK; //clock at 48/32 MHz
	490	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKEN;
	491	AT91C_BASE_TCB->TCB_BCR = 1;
	492
d10e08ae	493	tempo = AT91C_BASE_TC0->TC_CV;
818e15b0	494	for (u = 0; tab[u] != 0; u += 3) {
d10e08ae	495	// modulate antenna
d10e08ae	496	HIGH(GPIO_SSC_DOUT);
818e15b0	497	while(tempo != tab[u])
d10e08ae	498	tempo = AT91C_BASE_TC0->TC_CV;
caaa4293	499
d10e08ae	500	// stop modulating antenna
d10e08ae	501	LOW(GPIO_SSC_DOUT);
818e15b0	502	while(tempo != tab[u+1])
d10e08ae	503	tempo = AT91C_BASE_TC0->TC_CV;
d10e08ae	504
	505	// modulate antenna
	506	HIGH(GPIO_SSC_DOUT);
818e15b0	507	while(tempo != tab[u+2])
d10e08ae	508	tempo = AT91C_BASE_TC0->TC_CV;
d10e08ae	509	}
	510
	511	LED_A_OFF();
	512	FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
	513	SpinDelay(200);
	514
d10e08ae	515	AT91C_BASE_TC0->TC_CCR = AT91C_TC_CLKDIS; // timer disable
818e15b0	516	DbpString("Data frame sent (multiple sends may be needed)");
d10e08ae	517	LED(0xFFFF, 1000);
	518	}
	519
	520
caaa4293	521	/* Add a byte for building the data frame of PCF7931 tags
d10e08ae	522	* @param b : byte to add
	523	* @param tab : array of the data frame
	524	* @param l : offset on low pulse width
	525	* @param p : offset on low pulse positioning
	526	*/
818e15b0	527	bool AddBytePCF7931(uint8_t byte, uint32_t * tab, int32_t l, int32_t p) {
d10e08ae	528	uint32_t u;
818e15b0	529	for (u = 0; u < 8; ++u) {
caaa4293	530	if (byte & (1 << u)) { //bit is 1
d10e08ae	531	if(AddBitPCF7931(1, tab, l, p)==1)return 1;
818e15b0	532	} else { //bit is 0
d10e08ae	533	if(AddBitPCF7931(0, tab, l, p)==1)return 1;
	534	}
	535	}
	536
	537	return 0;
	538	}
	539
caaa4293	540	/* Add a bits for building the data frame of PCF7931 tags
d10e08ae	541	* @param b : bit to add
	542	* @param tab : array of the data frame
	543	* @param l : offset on low pulse width
	544	* @param p : offset on low pulse positioning
	545	*/
818e15b0	546	bool AddBitPCF7931(bool b, uint32_t * tab, int32_t l, int32_t p) {
d10e08ae	547	uint8_t u = 0;
d10e08ae	548
818e15b0	549	for (u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
d10e08ae	550
caaa4293	551	if (b == 1) { //add a bit 1
	552	if (u == 0) tab[u] = 34 * T0_PCF + p;
	553	else tab[u] = 34 * T0_PCF + tab[u-1] + p;
d10e08ae	554
818e15b0 S	555	tab[u+1] = 6 * T0_PCF+tab[u] + l;
818e15b0 S	556	tab[u+2] = 88 * T0_PCF+tab[u + 1] - l - p;
d10e08ae	557	return 0;
caaa4293	558	} else { //add a bit 0
d10e08ae	559
caaa4293	560	if (u == 0) tab[u] = 98 * T0_PCF + p;
caaa4293	561	else tab[u] = 98 * T0_PCF + tab[u-1] + p;
d10e08ae	562
818e15b0 S	563	tab[u + 1] = 6 * T0_PCF + tab[u] + l;
818e15b0 S	564	tab[u + 2] = 24 * T0_PCF + tab[u + 1] - l - p;
d10e08ae	565	return 0;
d10e08ae	566	}
caaa4293	567
d10e08ae	568	return 1;
	569	}
	570
	571	/* Add a custom pattern in the data frame
	572	* @param a : delay of the first high pulse
	573	* @param b : delay of the low pulse
	574	* @param c : delay of the last high pulse
	575	* @param tab : array of the data frame
	576	*/
818e15b0	577	bool AddPatternPCF7931(uint32_t a, uint32_t b, uint32_t c, uint32_t * tab) {
d10e08ae	578	uint32_t u = 0;
818e15b0	579	for(u = 0; tab[u] != 0; u += 3){} //we put the cursor at the last value of the array
d10e08ae	580
caaa4293	581	if (u == 0) tab[u] = a;
caaa4293	582	else tab[u] = a + tab[u - 1];
d10e08ae	583
818e15b0 S	584	tab[u + 1] = b + tab[u];
818e15b0 S	585	tab[u + 2] = c + tab[u + 1];
d10e08ae	586
	587	return 0;
	588	}