8051单片机(STC89C52)两个倒计时器异步计数

Myth丶恋晨 2021-12-12 03:39 268阅读 0赞

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl80MjA0ODQ2Mw_size_16_color_FFFFFF_t_70][]

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#include <STC89C5xRC.H>
    
    void delay()//用定时器0实现5ms精准定时
    {
    	TMOD = 0x01;
    	TH0 = 0xEA;
    	TL0 = 0x84;//65536 - 5000 = 60036
    
    	TF0 = 0;//置溢出标志位为0
    	TR0 = 1;//开启定时器0
    	while(TF0 == 0);
    	TR0 = 0;//暂停定时器0
    }
    
    void disp_digit(int d, int r)
    {
    	unsigned char code DIG_CODE[10] = {0x3f, 0x06, 0x5b, 0x4f, 0x66, 0x6d, 0x7d, 0x07, 0x7f, 0x6f};
    	//第一个倒计时
    	//显示个位数
    	P2 = 0;// P2 = 0 -> (P24, P23, P22) = (0, 0, 0) -> 右数第一个数字点亮
    	P0 = DIG_CODE[d % 10];
    	delay();//5ms精准定时
    	//显示十位数
    	P2 = 1 << 2;//P2 = 0000 0100 -> (P24, P23, P22) = (0, 0, 1) -> 右数第二个数字点亮
    	P0 = DIG_CODE[d / 10];
    	delay();//5ms精准定时
    	//第二个倒计时
    	//显示个位数
    	P2 = 6 << 2;//P2 = 0001 1000 -> (P24, P23, P22) = (1, 1, 0) -> 右数第七个数字点亮
    	P0 = DIG_CODE[r % 10];
    	delay();//5ms精准定时
    	//显示十位数
    	P2 = 7 << 2;//P2 = 0001 1100 -> (P24, P23, P22) = (1, 1, 1) -> 右数第八个数字点亮
    	P0 = DIG_CODE[r / 10];
    	delay();//5ms精准定时
    }
    
    int main()
    {
    	int i;
    	int sec1 = 15, sec2 = 25;
    	while(1)
    	{
    		if(sec1 == -1)
    		{
    			sec1 = 15;
    		}
    		if(sec2 == -1)
    		{
    			sec2 = 25;
    		}
    		for(i = 0; i < 50; i++)
    		{
    			disp_digit(sec1, sec2);//花费大约20ms
    		}
    		sec1 --;
    		sec2 --;
    	}
    	return 0;
    }

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