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);
			}