pic16f877a的AD实验学习

一、主函数

//采集AD值

#include <pic.h>
#include "ad.h"
#include "usart.h"

__CONFIG(0xFF32);

const uchar disp[]={0x3f,0x06,0x5b,0x4f,0x66,0x6d,0x7d,
                        0x07,0x7f,0x6f};

//延时函数
void delayms(uint x)
{
    uint j,k;
    for(j=x;j>0;j--)
     for(k=110;k>0;k--);
}

//显示4位，低位数码管显示不正常
void display(uint x)
{
    PORTD= disp[x/1000]|0x80;
    PORTA= 0x10;
    delayms(2);

       PORTD= disp[x/100%10];
      PORTA= 0x08;
    delayms(4);

       PORTD= disp[x/10%10];
       PORTA= 0x04;
    delayms(2);

       PORTD= disp[x%10];
       PORTA= 0x02;
    delayms(2);
}



//初始化IO
void init()
{
    TRISA = 0x01;            //RA0 input mode
    TRISC = 0xff;                //RC output mode
    TRISD = 0;
    PORTC = 0x01;

    ADCON0 = 0x41;            //ADCS1:ADCS0=01,AN0,,A/D On
    ADCON1 = 0x8E;            //right justified,ADCS2=0,1110
    delayms(10);
}

//获取AD值
uint getad()
{
    uint adval;
    float advalf;
    GO = 1;
    while(GO);
    adval = ADRESH;
    adval = adval<<8|ADRESL;
    advalf = adval/1023.0*5.0;                //转换成电压
    adval = (uint)(advalf*1000);            //转换成4位整型
    return (adval);
}

void main()
{
    uint i = 0;
    uint temp;
    init();
    usart_init();
    while(1)
    {
        temp = getad();
        display(temp);
        if(i == 100)
        {
            usart_tx(temp>>8);
            usart_tx(temp);
            i=0;
        }
        delayms(5);
        i++;
    }
}

二、usart函数

#include <pic.h>
#include "usart.h"

//串口初始化
void usart_init(void)
{
    SPBRG = 0xC;                //波特率19200
    TXSTA = 0x24;                //开启发送，高速模式
    RCSTA = 0X90;                //使能TXRX引脚，接收到CREN直到被清零
    RCIE = 0X1;                    //使能接受中断
    GIE = 0X1;                    //开启总中断
    PEIE = 0X1;                    //开启串口中断
}

void interrupt usart(void)
{
    if(RCIE && RCIF)
    {
        TXREG = RCREG;            //返回接收的数据
    }
}

void usart_tx(unsigned char date)
{
    TXREG = date;
    while(TRMT!=1);
}