简易数字电压表+ADC0809+程序查询方式实现8路数据转换

1 实验现象（每间隔1s自动切换模拟信号采集通道，通过数码管显示测量的电压值）

2 硬件设计

3 程序设计

3.1 主函数

#include <REG52.H>
#include "DisplaySmg.h"
#include "ADC0809.h"
#include "Timer0.h"

unsigned char  adc_result = 0;    //ADC转换后直接采集的数据
int adc_result_show = 0;        //线性标度变化
unsigned char  adc_flag   = 1;    //1s时间的标志信号，用来自动切换通道
unsigned char  channel      = 0;    //通道号0~7

void disp_num(void)            //显示四位十进制数
{
    LedBuf[0]= channel;                    //通道号
    LedBuf[1]= adc_result_show/100;        //百位
    LedBuf[2]= adc_result_show/10%10;    //十位
    LedBuf[3]= adc_result_show%10;        //个位
}

void main()
{
    Timer0_Init();        //定时/计数器T0初始化
    EA=1;                //中断总开关
    DotDig1=1;            //点亮第二个数码管的小数点
    while(1)
    {
        if(adc_flag==1)                        //1S时间标志信号
        {
            adc_flag = 0;                    //清零,使用Timer0计时
            adc_result = ADC_Conv(channel);    //通过ADC采集通道channel输入端数据
            adc_result_show = adc_result*1.0*100*5/255;    //数据变换处理(线性标度变换)
            disp_num();                                    //显示数据
            channel++;                                    //切换下一个通道
            if(channel>7)  channel = 0;
        }
    }
}

//1ms定时，动态刷新数码管，同时每隔1000ms刷新adc_flag=1
void Timer0_ISR(void) interrupt 1
{
    static unsigned int timer0cnt;

    TR0=0;                //关闭定时器
    timer0cnt++;
    if(timer0cnt>=1000)
    {
        timer0cnt = 0;
        adc_flag  = 1;
    }
    DisplaySmg();        //每过1ms,刷新一次数码管显示函数
    TL0 = 0x66;            //设置定时初始值,定时1ms
    TH0 = 0xFC;            //设置定时初始值,定时1ms
    TR0=1;                //打开定时器
}

3.2 ADC0809模数转换函数

#ifndef __ADC0809_H__
#define __ADC0809_H__

#include <reg52.h>

#define ADC_DATA P3

sbit ADDR_A = P1^0;
sbit ADDR_B = P1^1;
sbit ADDR_C = P1^2;
sbit START    = P1^4;
sbit EOC    = P1^5;
sbit OE        = P1^6;

unsigned char ADC_Conv(unsigned char channel);

#endif

#include "ADC0809.h"

void ADC_SetChannel(channel)
{
    switch(channel)
    {
        case 0: ADDR_A = 0; ADDR_B = 0; ADDR_C = 0; break;
        case 1: ADDR_A = 1; ADDR_B = 0; ADDR_C = 0; break;
        case 2: ADDR_A = 0; ADDR_B = 1; ADDR_C = 0; break;
        case 3: ADDR_A = 1; ADDR_B = 1; ADDR_C = 0; break;
        case 4: ADDR_A = 0; ADDR_B = 0; ADDR_C = 1; break;
        case 5: ADDR_A = 1; ADDR_B = 0; ADDR_C = 1; break;
        case 6: ADDR_A = 0; ADDR_B = 1; ADDR_C = 1; break;
        case 7: ADDR_A = 1; ADDR_B = 1; ADDR_C = 1; break;
        default: break;
    }
}

unsigned char ADC_Conv(unsigned char channel)
{
    unsigned char adc_result;

    OE = 0;     //数据输出允许信号，高电平有效
    START = 0;     //ADC转换启动信号，高电平有效, 电路中与ALE(地址锁存允许信号)连在一起

    ADC_SetChannel(channel);    //选通道

    START = 1;    //上升沿，同时将ADC内部的寄存器清零
    START = 0;    //产生一定的脉冲，Typ=100ns,下降沿启动AD转换

    while(EOC==0); //查询方式，ADC转换结束信号，EOC=1，转换结束
//    DelayXms(1);    //延时等待方式
    OE = 1;        //数据更新到输出端口
    adc_result = ADC_DATA;    //单片机读取数据
    OE = 0;        //本次过程结束
    return adc_result;
}

3.3 数码管动态显示函数

#ifndef __DisplaySmg_H__
#define __DisplaySmg_H__

#include <REG52.H>

#define GPIO_SEG P0        //段选端
#define GPIO_SEL P2        //位选端

extern unsigned char LedBuf[];    //外部变量声明
extern unsigned char DotDig0,DotDig1,DotDig2,DotDig3;

void DisplaySmg(void);

#endif

#include "DisplaySmg.h"

unsigned char code LedData[]={    //共阴型数码管的段码表，字符，序号
                0x3F,  //"0"，0
                0x06,  //"1"，1
                0x5B,  //"2"，2
                0x4F,  //"3"，3
                0x66,  //"4"，4
                0x6D,  //"5"，5
                0x7D,  //"6"，6
                0x07,  //"7"，7
                0x7F,  //"8"，8
                0x6F,  //"9"，9
                0x77,  //"A"，10
                0x7C,  //"B"，11
                0x39,  //"C"，12
                0x5E,  //"D"，13
                0x79,  //"E"，14
                0x71,  //"F"，15
                0x76,  //"H"，16
                0x38,  //"L"，17
                0x37,  //"n"，18
                0x3E,  //"u"，19
                0x73,  //"P"，20
                0x5C,  //"o"，21
                0x40,  //"-"，22
                0x00,  //熄灭 23
                         };
unsigned char DotDig0=0,DotDig1=0,DotDig2=0,DotDig3=0;    //小数点控制位
unsigned char code LedAddr[]={0xfe,0xfd,0xfb,0xf7};        //数码管位选
unsigned char LedBuf[]={22,22,22,22};    //显示缓存区

void DisplaySmg()                    //四位数码管，考虑小数点
{
    unsigned char     i;                 //等价于 "static unsigned char i = 0;"
    unsigned char     temp;
    switch(i)
    {
        case 0:
        {
            GPIO_SEG = 0x00;                //消影
            if(DotDig0==1)                    //小数点
            {
                temp = LedData[LedBuf[0]] | 0x80;  //点亮小数点
            }
            else
            {
                temp = LedData[LedBuf[0]];
            }
            GPIO_SEG = temp;                //段码
            GPIO_SEL = LedAddr[0];            //位选
            i++;
            break;
        }

        case 1:
            GPIO_SEG = 0x00;
            if(DotDig1==1)                    //小数点
            {
                temp = LedData[LedBuf[1]] | 0x80;
            }
            else
            {
                temp = LedData[LedBuf[1]];
            }
            GPIO_SEG = temp;
            GPIO_SEL = LedAddr[1];
            i++;
            break;
        case 2:
            GPIO_SEG = 0x00;
            if(DotDig2==1)                    //小数点
            {
                temp = LedData[LedBuf[2]] | 0x80;
            }
            else
            {
                temp = LedData[LedBuf[2]];
            }
            GPIO_SEG = temp;
            GPIO_SEL = LedAddr[2];
            i++;
            break;
        case 3:
            GPIO_SEG = 0x00;
            if(DotDig3==1)                    //小数点
            {
                temp = LedData[LedBuf[3]] | 0x80;
            }
            else
            {
                temp = LedData[LedBuf[3]];
            }
            GPIO_SEG = temp;
            GPIO_SEL = LedAddr[3];
            i=0;
            break;
        default:break;
    }
}

3.4 定时器T0

#ifndef __Timer0_H__
#define __Timer0_H__

#include <reg52.h>

void Timer0_Init(void);

#endif

#include "Timer0.h"

void Timer0_Init(void)        //1毫秒@11.0592MHz
{
    TMOD &= 0xF0;        //设置定时器模式
    TMOD |= 0x01;        //设置定时器模式
    TL0 = 0x66;            //设置定时初始值
    TH0 = 0xFC;            //设置定时初始值
    TF0 = 0;            //清除TF0标志
    TR0 = 1;            //定时器0开始计时

    ET0 = 1;            //定时器0中断开关
//    EA  = 1;             //中断总开关
}

4 参考来源

（1）单片机应用——ADC0809查询方式实现8路模拟信号的AD转换_哔哩哔哩_bilibili；