DAtransform.c

#include<reg52.h>
#define uchar unsigned char
#define uint unsigned int

sbit dula = P2^6;   // u1 的锁存器的锁存端
sbit wela = P2^7; 	// u2 锁存器的锁存端
sbit dawr = P3^6;	// DA 的WR端口
sbit dacs = P3^2;	// DA 的CS端口
sbit beep = P2^3;	// 定义蜂鸣器


void delayms(uint xms)
{
	uint i,j;
	for (i = xms; i > 0; i--)
		for (j = 110; j>0; j--);
}

void main ()
{
	uchar val,flag;

	dula = 0;
	wela = 0;
	dacs = 0;
	dawr = 0;
	P0 = 0;

	while(1)
	{
		if (flag == 0)
		{
			val += 5;
			P0=val;   //P0 端与DA数据口连接，可以对其赋值
			if (val == 255)
			{
				flag = 1;
				beep = 0;
				delayms(100);
				beep = 1;
			}
			delayms(50);

		}
		else
		{
			val -= 5;
			P0 = val;
			if(val == 0)
			{
				flag = 0;
				beep = 0;
				delayms(100);
				beep=1;

			}
			delayms(50);
		}
	}


}