[proxmark3-svn] / armsrc / pcf7931.c

#include "proxmark3.h"
#include "apps.h"
#include "lfsampling.h"
#include "pcf7931.h"
#include "util.h"
#include "string.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
	if (block[10] == 0 && block[11] == 0 && block[12] == 0 && block[13] == 0)
		if((block[14] & 0x7f) <= 9 && block[15] <= 9)
			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) {
			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;

			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);
					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);

		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;
		}
		
		pass_array[0] = password & 0xFF;
		pass_array[1] = (password >> 8) & 0xFF;
		pass_array[2] = (password >> 16) & 0xFF;
		pass_array[3] = (password >> 24) & 0xFF;
		pass_array[4] = (password >> 32) & 0xFF;
		pass_array[5] = (password >> 40) & 0xFF;
		pass_array[6] = (password >> 48) & 0xFF;

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