1.使用两种定时方法闪烁发光二极管。
#include<reg52.h> sbit LED = P0^0; sbit ADDR0 = P1^0; sbit ADDR1 = P1^1; sbit ADDR2 = P1^2; sbit ADDR3 = P1^3; sbit ENLED = P1^4; void main() { unsigned int i = 0; ENLED = 0; ADDR3 = 1; ADDR2 = 1; ADDR1 = 1; ADDR0 = 0; while (1) { LED = 0; for (i=0; i<30000; i ); LED = 1; for (i=0; i<30000; i ); } } 从100开始编写倒计时程序(可编写从100开始倒计时的程序(可显示高位0)。
#include <reg52.h> sbit LED = P0^0; sbit ADDR0 = P1^0; sbit ADDR1 = P1^1; sbit ADDR2 = P1^2; sbit ADDR3 = P1^3; sbit ENLED = P1^4; void main() { unsigned char cnt = 0; ENLED = 0; ADDR3 = 1; ADDR2 = 1; ADDR1 = 1; ADDR0 = 0; TMOD = 0x01; TH0 = 0xB8; TL0 = 0x00; TR0 = 1; while (1) { if (TF0 == 1) { TF0 = 0; TH0 = 0xB8; TL0 = 0x00; cnt ; if (cnt >= 50) { cnt = 0; LED = ~LED; } } } } 2.采用中断的方式，使用数字管显示，从100开始编写倒计时程序(可显示高位0)。
#include <reg52.h> sbit ADDR0 = P1^0; sbit ADDR1 = P1^1; sbit ADDR2 = P1^2; sbit ADDR3 = P1^3; sbit ENLED = P1^4; unsigned char code LedChar[] = { 0xC0, 0xF9, 0xA4, 0xB0, 0x99, 0x92, 0x82, 0xF8, 0x80, 0x90, 0x88, 0x83, 0xC6, 0xA1, 0x86, 0x8E }; unsigned char LedBuff[3] = { 0xFF, 0xFF, 0xFF}; unsigned char i,j = 0; unsigned int cnt = 0; unsigned char flag1s = 0; void main() { unsigned long sec = 101; EA = 1; //使能总中断 ENLED = 0; //使能U3，选择控制数码管 ADDR3 = 1; ///因需要动态变化ADDR0-2的值不需要初始化 TMOD = 0x01; //设置T0为模式1 TH0 = 0xFC; //为T0赋初值0xFC67，定时1ms TL0 = 0x67; ET0 = 1; //使能T0中断 TR0 = 1; //启动T0 while (1) { if (flag1s == 1) { flag1s = 0; sec--; LedBuff[0] = LedChar[sec]; LedBuff[1] = LedChar[sec/10]; LedBuff[2] = LedChar[sec/100]; } } } void InterruptTimer0() interrupt 1 { TH0 = 0xFC; ///重新加载初始值 TL0 = 0x67; cnt ; if (cnt >= 1000) { cnt = 0; flag1s = 1; } P0 = 0xFF; switch (i) { case 0: ADDR2=0; ADDR1=0; ADDR0=0; i ; P0=LedBuff[0]; break; case 1: ADDR2=0; ADDR1=0; ADDR0=1; i ; P0=LedBuff[1]; break; case 2: ADDR2=0; ADDR1=1; ADDR0=0; i=0; P0=LedBuff[2]; break; default: break; } }