#include <reg51.h>
#include <intrins.h>

unsigned char time;
void int_t0(void) interrupt 1 {
	time++;
}

unsigned char d;	//rec data

bit rec(void) {
	TH0=0;time=0;
	while (!RI) {if (time>1) return(1);}
	RI=0;
	d=SBUF;
	return(0);
}
void sen(unsigned char dd) {
	SBUF=dd;
	while (!TI) {}
	TI=0;
}

void wait(void) {
	time=0;while (time<10) {}
}

void wait10ms(void) {
	TH0=150;time=0;
	while (!time) {}
}

sbit ce=P3^5;
sbit oe=P3^6;
sbit we=P3^7;
sbit a16=P3^2;
sbit a17=P3^3;
sbit a18=P3^4;



void pro_to_card(void) {
	unsigned char no,i,j;
	sen(0xaa);
	if (rec()) {wait();return;}
	no=d;
	sen(d);
	
	no<<=2;
	no|=0xe3;
	P3=0xff;
	P3&=no;
	
	i=0;
	do {
		P0=i;
		j=0;
		do {
			if (rec()) {wait();ce=1;return;}
			TI=0;SBUF=d;
			P1=j;
			P2=d;
			ce=0;
			we=0;
			we=1;
			ce=1;
			j++;
		} while (j);
		wait10ms();
		i++;
	} while (i);
	ce=1;
}

void card_to_pro(void) {
	unsigned char no,i,j;
	sen(0x55);
	if (rec()) {wait();return;}
	no=d;
	sen(d);

	no<<=2;
	no|=0xe3;
	P3=0xff;
	P3&=no;
	P2=0xff;

	i=0;
	do {
		P0=i;
		j=0;
		do {
			P1=j;
			ce=0;oe=0;
			no=P2;
			oe=1;ce=1;
			j++;
			sen(no);
			if (rec()) {wait();return;}
			if (no!=d) {wait();return;}
		} while (j);
		i++;
	} while (i);
}




/*
void load(unsigned int as,unsigned char dd) {
	P0=as/256;P1=as;P2=dd;
	ce=0;we=0;we=1;ce=1;
}
void erase(void) {
	a16=a17=a18=0;
	load(0x5555,0xaa);
	load(0x2aaa,0x55);
	load(0x5555,0x80);
	load(0x5555,0xaa);
	load(0x2aaa,0x55);
	load(0x5555,0x10);
	wait10ms();
	wait10ms();
}

void unlock(void) {
	unsigned char i;
	a16=a17=a18=0;
	load(0x5555,0xaa);
	load(0x2aaa,0x55);
	load(0x5555,0x80);
	load(0x5555,0xaa);
	load(0x2aaa,0x55);
	load(0x5555,0x20);
	i=0;
	do {
		P1=i;
		ce=0;we=0;we=1;ce=1;
		i++;
	} while (i);
}
*/

void main(void) {
	SCON=0x80;
	TMOD=0x21;
	ET0=TR0=1;EA=1;
	
	
	
	wait10ms();
//	erase();
//	unlock();
	REN=1;
	while (1) {
		REN=1;RI=0;
		while (!RI) {} RI=0;
		switch (SBUF) {
		case 0x55:card_to_pro();break;
		case 0xaa:pro_to_card();break;
		case 0xa5:
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			_nop_();
			sen(0xaa);
			break;
		}
	}
}