PIC单片机(PIC16F877A)定时器

#include<pic.h>
#define uchar unsigned char
#define uint unsigned int
uchar i,temp;
uchar count;
void delay(uint x)	//1ms
{
uint y,z;
for(y=x;y>0;y--)
for(z=25;z>0;z--);
}
void init(void)
{
T1CON=0x01;//使能定时器1，时钟为外部晶振四分频
PIE1|=0x01;//允许中断
INTCON|=0xc0;//开全局中断和第一外设中断
TMR1H=15536/256;//50ms初值
TMR1L=15536%256;
}
void interrupt timer1(void)
{
if(TMR1IE&&TMR1IF)
{
TMR1H=(65535-50000)/256;
TMR1L=(65535-50000)%256;
count++;
TMR1IF=0;//中断标志位清零
if(count==20)
{
count=0;
if(i<8)
{
PORTD=temp;
temp<<=1;
i++;
}
else
{
i=0;
temp=0x01;
}
}
}
}

void main(void)
{
TRISD=0x00;
PORTD=0x00;
temp=0x01;
i=0;
init();
while(1);
}