单片机定时器0 定时1s

#include "reg51.h" sbit LED=P2^0; unsigned char num; void main() { TMOD=0X01; TH0=(65536-50000)/256; TL0=(65536-50000)%256; ET0=1; EA=1; PT0=0; TR0=1; while(1) { } } void timer0() interrupt 1 { TH0=(65536-50000)/256;// TL0=(65536-50000)%256;// 必须要重新装，否则从0计 num++; if(num==19) { num=0; LED=!LED; } }