PIC单片机定时器的使用（16F877）

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//功能：60倒计时，蜂鸣器以及数码管的使用

//开发板：PIC16F877

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include

define uchar unsigned char

define uint unsigned int

void delay(uchar a,uchar x);

uchar table[]={0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0x00};//数组

uchar LED[3];

void init();//初始化函数

void interrupt TMRO();//TMRO中断函数

uint counter;

uchar tmro_counter;

void LED_DISP();//数码管的显示函数

main()

{

init();

counter=60;

while(1)

{

//counter=60;

LED[1]=(uchar)(counter/10);

LED[2]=(uchar)(counter%10);

LED_DISP();

//counter–;

//if(counter==0)

//RE0=1;

}

}

void init()

{

TRISC=0X00;

TRISA=0X00;

TRISD=0X00;

PORTD=0XFF;

TRISE=0x00;

RC5=0;

OPTION_REG=0X07;//256分频

TMR0=61;

INTCON=0Xa0;

}

void interrupt TMRO()

{

TMR0IF=0;

//TMR0=158;

tmro_counter++;

if(tmro_counter==20)

{

tmro_counter=0;

tmro_counter++;

counter–;

if(counter==0)

RE0=1;

}

TMR0=61;

}

void LED_DISP()

{

uchar timer=0;

uchar temp=0x80;

RA3=0;

//for(k=0;k<=50;k++)

for(timer=1;timer<=2;timer++)

{

RC4=1;

PORTD=temp;

RC4=0;

RC3=1;

PORTD=table[LED[timer]];

RC3=0;

temp>>=1;

delay(10,10);

RC4=1;

PORTD=0X00;

RC4=0;

delay(1,10);

}

}

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/*延迟函数***

/************************

void delay(uchar a,uchar x)

{

while(–a)

while(–x);

}