給大家介紹一個(gè)51單片機(jī)讀寫(xiě)AT29C040的c51程序

＃include
＃include

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);
}
*/

//AT29C040讀寫(xiě)主程序開(kāi)始

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;
}
}
}