8051单片机(STC89C52)以定时器中断模式实现两倒计时器异步计时

谁践踏了优雅 2021-12-10 05:53 426阅读 0赞

相较单倒计时器对timer0初值的设定, 此处将中断处理程序触发时间间隔改为5ms, 目的是给人在视觉上以更好的体验(设定为10ms会明显感觉到闪烁).

#include <STC89C5xRC.H>
    
    unsigned char code DIG_CODE[10] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f};//对应数码管显示0~9
    
    int tcount = 0;//记录经过的5ms区间段个数
    
    int sec1 = 15, sec2 = 25;//倒计时初始值
    
    void T0_INT() interrupt 1 //timer0中断, 每5ms触发一次
    {
    	TR0 = 0;//关闭timer0
    	TH0 = 0xEC;
    	TL0 = 0x78;//65536 - 5000 = 60536
    	if(tcount % 4 == 0)
    	{
    		//显示个位数(第一个倒计时器)
    		P2 = 0;// P2 = 0 -> (P24, P23, P22) = (0, 0, 0) -> 右数第一个数字点亮
    		P0 = DIG_CODE[sec1 % 10];
    		tcount ++;
    	}
    	else if(tcount % 4 == 1)
    	{
    		//显示十位数(第一个倒计时器)
    		P2 = 1 << 2;//P2 = 0000 0100 -> (P24, P23, P22) = (0, 0, 1) -> 右数第二个数字点亮
    		P0 = DIG_CODE[sec1 / 10];
    		tcount ++;
    	}
    	else if(tcount % 4 == 2)
    	{
    		//显示个位数(第二个倒计时器)
    		P2 = 100 << 2;//P2 = 0001 0000 -> (P24, P23, P22) = (1, 0, 0) -> 右数第五个数字点亮
    		P0 = DIG_CODE[sec2 % 10];
    		tcount ++;
    	}
    	else if(tcount % 4 == 3)
    	{
    		//显示十位数(第二个倒计时器)
    		P2 = 101 << 2;//P2 = 0001 0100 -> (P24, P23, P22) = (1, 0, 1) -> 右数第六个数字点亮
    		P0 = DIG_CODE[sec2 / 10];
    		tcount ++;
    	}
    	if(tcount == 200) //5ms * 200 = 1000ms = 1s -> 1s时间到
    	{
    	 	tcount = 0;
    		sec1 --;
    		sec2 --;
    		if(sec1 == -1)
    		{
    			sec1 = 15;
    		}
    		if(sec2 == -1)
    		{
    			sec2 = 25;
    		}
    	}
    	TR0 = 1;//重新开启timer0
    }
     
    int main()
    {
    	TMOD = 0x01;
    	TH0 = 0xEC;
    	TL0 = 0x78;//65536 - 5000 = 60536
    	IE = 0x82;
    	TR0 = 1;//开启timer0
    	while(1)
    	{
    		;
    	}
    	return 0;
    }

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