main.c文件

#include <reg52.h>   
#include <stdio.h>
#include "1602.h"
#include "delay.h"
#define uint unsigned int 
#define uchar unsigned char 
/****ADC0809引脚定义********************/
sbit CLK=P2^6;
sbit ST=P2^3;
sbit ALE=P2^7; 
sbit OE=P2^5; 
sbit EOC=P2^4; 
sbit ADDA=P3^5;
sbit ADDB=P3^6;
sbit ADDC=P3^7;
/*****按键定义*****/
sbit KEY1=P3^2;
sbit KEY2=P3^3;
sbit KEY3=P3^4;
/*****º函数声明*************/
void ADC0809_init();	//ADC0809初始化函数
unsigned char  Read_AD();  //读取AD数据函数
unsigned char  keyscan();  //通道选择函数

void main()
{
	 uchar num=0;
	 unsigned char temp[7];//显示区域临时存储数组
	 float Voltage;        //浮点变量
	 ADC0809_init();
	 LCD_Init();           //LCD初始化
	 DelayMs(20);          
	 LCD_Clear();          //清屏
	 LCD_Write_String(3,0,"PYH_DVM /V");	//设置表头
	 ADC0809_init();   //AD0809初始化

	 ST=0;
	while(1)
	{
		ST=1;			//启动ADC0809
		ST=0;
	    keyscan();  //0~2
		num=Read_AD();  //读取AD0809数据
		Voltage=(float)num*5/256; //数据转换，float是强制转换符号，将结果转换为浮点型
        sprintf(temp,"VO:%3.2f ",Voltage);  //格式输出电压值，%3.2表示浮点输出，小数点后两位
        LCD_Write_String(2,1,temp);  //将数据写入1602显示
		
		}
}
	


void timer0(void) interrupt 1    //中断处理函数，产生约500KHz时钟供0809工作
{
	TH0=(65536-200)/256;
	TL0=(65536-200)%256;
	CLK=~CLK;
 
}

void ADC0809_init()   //ADC0809初始化
{
	TMOD=0x01;
	TH0=(65536-200)/256;
	TL0=(65536-200)%256;
	ET0=1;
	TR0=1;
	EA=1;
	DelayMs(2);
}

unsigned char  Read_AD()  //读ADC0809数据
{
	uchar temp=0; 	//存放AD采集的数据
	while(EOC==0);	//等待转换完成
	 	 OE=1;
		 temp=P1;      //读取数据
		 DelayMs(1);
		 OE=0;
		 return temp;
}

unsigned char keyscan()
{ 
	
	if(KEY1==0)//选择通道0
	{
		  ALE=1;  //允许写入地址
		  ADDA=0;
		  ADDB=0;
		  ADDC=0;
	      ALE=0;
		
		}
	 else if(KEY2==0)  //选择通道1
	      {
					ALE=1;
					ADDA=1;
					ADDB=0;
					ADDC=0;
					ALE=0;
				 
	  }
		else if(KEY3==0)  //选择通道2
		    {
					ALE=1;
					ADDA=0;
					ADDB=1;
					ADDC=0;
					ALE=0;
		}
	/****其他通道同理写入地址即可********/
}




#ifndef __DELAY_H__
#define __DELAY_H__
/*------------------------------------------------
us延时函数，含参，t值范围0~255
------------------------------------------------*/
void DelayUs2x(unsigned char t);
/*------------------------------------------------
ms延时函数，含参，t值范围0~255
------------------------------------------------*/
void DelayMs(unsigned char t);
#endif


#include "delay.h"

void DelayUs2x(unsigned char t)
{   
 while(--t);
}
void DelayMs(unsigned char t)
{
     while(t--)
 {
     //大致延时1ms
     DelayUs2x(245);
	 DelayUs2x(245);
 }
}

#include<reg52.h> //
#include<intrins.h>

#ifndef __1602_H__
#define __1602_H__

 bit LCD_Check_Busy(void) ;
 void LCD_Write_Com(unsigned char com) ;
 void LCD_Write_Data(unsigned char Data) ;

 void LCD_Clear(void) ;
 void LCD_Write_String(unsigned char x,unsigned char y,unsigned char *s) ;
 void LCD_Write_Char(unsigned char x,unsigned char y,unsigned char Data) ;
 void LCD_Init(void) ;
   
#endif

1602.c文件

#include "1602.h"
#include "delay.h"

sbit RS = P2^0;   //端口定义
sbit RW = P2^1;
sbit EN = P2^2;

#define RS_CLR RS=0 
#define RS_SET RS=1

#define RW_CLR RW=0 
#define RW_SET RW=1 

#define EN_CLR EN=0
#define EN_SET EN=1

#define DataPort P0

/*------------------------------------------------
       判忙函数
------------------------------------------------*/
 bit LCD_Check_Busy(void) 
 { 
 DataPort= 0xFF; 
 RS_CLR; 
 RW_SET; 
 EN_CLR; 
 _nop_(); 
 EN_SET;
 return (bit)(DataPort & 0x80);
 }
/*------------------------------------------------
           写入命令函数
------------------------------------------------*/
 void LCD_Write_Com(unsigned char com) 
 {  
 DelayMs(5);
 RS_CLR; 
 RW_CLR; 
 EN_SET; 
 DataPort= com; 
 _nop_(); 
 EN_CLR;
 }
/*------------------------------------------------
       写入数据函数
------------------------------------------------*/
 void LCD_Write_Data(unsigned char Data) 
 { 
 DelayMs(5);
 RS_SET; 
 RW_CLR; 
 EN_SET; 
 DataPort= Data; 
 _nop_();
 EN_CLR;
 }

/*------------------------------------------------
               清屏函数
------------------------------------------------*/
 void LCD_Clear(void) 
 { 
 LCD_Write_Com(0x01); 
 DelayMs(5);
 }
/*------------------------------------------------
      写入字符串函数
------------------------------------------------*/
 void LCD_Write_String(unsigned char x,unsigned char y,unsigned char *s) 
 {     
 if (y == 0) 
 	{     
	 LCD_Write_Com(0x80 + x);     //表示第一行
 	}
 else 
 	{      
 	LCD_Write_Com(0xC0 + x);      //表示第二行
 	}        
 while (*s) 
 	{     
 LCD_Write_Data( *s);     
 s ++;     
 	}
 }
/*------------------------------------------------
        写入字符函数
------------------------------------------------*/
/* void LCD_Write_Char(unsigned char x,unsigned char y,unsigned char Data) 
 {     
 if (y == 0) 
 	{     
 	LCD_Write_Com(0x80 + x);     
 	}    
 else 
 	{     
 	LCD_Write_Com(0xC0 + x);     
 	}        
 LCD_Write_Data( Data);  
 }*/
/*------------------------------------------------
        初始化函数
------------------------------------------------*/
 void LCD_Init(void) 
 {
   LCD_Write_Com(0x38);    /*显示模式设置*/ 
   DelayMs(5); 
   LCD_Write_Com(0x38); 
   DelayMs(5); 
   LCD_Write_Com(0x38); 
   DelayMs(5); 
   LCD_Write_Com(0x38);  
   LCD_Write_Com(0x08);    /*显示关闭*/ 
   LCD_Write_Com(0x01);    /*显示清屏*/ 
   LCD_Write_Com(0x06);    /*显示光标移动设置*/ 
   DelayMs(5); 
   LCD_Write_Com(0x0C);    /*Ï显示开关及光标设置*/
   }