蓝桥杯——AD模块

一、原理部分

在iic.c中增加代码

void write_adc(unsigned char add)//要用哪一个通道在调用时就写哪一个
{
	 IIC_Start();
	 IIC_SendByte(0x90);
	 IIC_WaitAck();
	 IIC_SendByte(add);
	 IIC_WaitAck();
	 IIC_Stop();
}

unsigned char read_adc(unsigned char add)//和上面的用法一样
{
	 unsigned char temp;
	 EA = 0;
	 IIC_Start();
	 IIC_SendByte(0x90);
	 IIC_WaitAck();
	 IIC_SendByte(add);
	 IIC_WaitAck();
	 IIC_Start();
	 IIC_SendByte(0x91);
	 IIC_WaitAck();
	 temp = IIC_RecByte();
	 IIC_WaitAck();
	 IIC_Stop();
	 EA = 1;
	 return temp;
}

在iic.h中增加代码

void write_adc(unsigned char add);
unsigned char read_adc(unsigned char add);

在主函数中包含头文件iic.h
iic.h中包含stc15f2k60s2.h

在写寄存器的时候使用P2 = P2&0x1f|[对应的码值]，这样可以清除写寄存器时对其他位的干扰。例如打开蜂鸣器的寄存器写为P2 = P2&0x1f|0xa0；同理 关闭寄存器的时候写成P2 = P2&0x1f。

二、代码部分

实验平台：CT107D
实验芯片：stc15f2k60s2
实验现象：数码管显示电位器1当前的电压值
代码如下
iic.h

#include "iic.h"
void Delay5us()		//@12.000MHz
{
	unsigned char i;

	_nop_();
	_nop_();
	i = 12;
	while (--i);
}


//总线启动条件
void IIC_Start(void)
{
	SDA = 1;
	SCL = 1;
	somenop;
	SDA = 0;
	somenop;
	SCL = 0;	
}

//总线停止条件
void IIC_Stop(void)
{
	SDA = 0;
	SCL = 1;
	somenop;
	SDA = 1;
}

//应答位控制
void IIC_Ack(unsigned char ackbit)
{
	if(ackbit) 
	{	
		SDA = 0;
	}
	else 
	{
		SDA = 1;
	}
	somenop;
	SCL = 1;
	somenop;
	SCL = 0;
	SDA = 1; 
	somenop;
}

//等待应答
bit IIC_WaitAck(void)
{
	SDA = 1;
	somenop;
	SCL = 1;
	somenop;
	if(SDA)    
	{   
		SCL = 0;
		IIC_Stop();
		return 0;
	}
	else  
	{ 
		SCL = 0;
		return 1;
	}
}

//通过I2C总线发送数据
void IIC_SendByte(unsigned char byt)
{
	unsigned char i;
	for(i=0;i<8;i++)
	{   
		if(byt&0x80) 
		{	
			SDA = 1;
		}
		else 
		{
			SDA = 0;
		}
		somenop;
		SCL = 1;
		byt <<= 1;
		somenop;
		SCL = 0;
	}
}

//从I2C总线上接收数据
unsigned char IIC_RecByte(void)
{
	unsigned char da;
	unsigned char i;
	
	for(i=0;i<8;i++)
	{   
		SCL = 1;
		somenop;
		da <<= 1;
		if(SDA) 
		da |= 0x01;
		SCL = 0;
		somenop;
	}
	return da;
}

void write_adc(unsigned char add)
{
	 IIC_Start();
	 IIC_SendByte(0x90);
	 IIC_WaitAck();
	 IIC_SendByte(add);
	 IIC_WaitAck();
	 IIC_Stop();
}
//下面为自己写的
unsigned char read_adc(unsigned char add)
{
	 unsigned char temp;
	 EA = 0;
	 IIC_Start();
	 IIC_SendByte(0x90);
	 IIC_WaitAck();
	 IIC_SendByte(add);
	 IIC_WaitAck();
	 IIC_Start();
	 IIC_SendByte(0x91);
	 IIC_WaitAck();
	 temp = IIC_RecByte();
	 IIC_WaitAck();
	 IIC_Stop();
	 EA = 1;
	 return temp;
}

iic.h

#ifndef _IIC_H
#define _IIC_H

#include "stc15f2k60s2.h"
#include "intrins.h"

#define somenop Delay5us()
#define SlaveAddrW 0xA0
#define SlaveAddrR 0xA1

//总线引脚定义
sbit SDA = P2^1;  /* 数据线 */
sbit SCL = P2^0;  /* 时钟线 */

//函数声明
void IIC_Start(void); 
void IIC_Stop(void);  
void IIC_Ack(unsigned char ackbit); 
void IIC_SendByte(unsigned char byt); 
bit IIC_WaitAck(void);  
unsigned char IIC_RecByte(void); 

void Delay5us();
//下面为自己写的
void write_adc(unsigned char add);
unsigned char read_adc(unsigned char add);

#endif

main.c

#include<stc15f2k60s2.h>
#include <iic.h>
#define uchar unsigned char
#define uint unsigned int

uchar duan[] = {0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F,0x00,0x40};
uchar disbuff[8];

uchar adc_value;

void clzbuzz()
{
	P2 = P2&0x1f|0xa0;
	P0 = 0xaf;
	P2 = P2&0x1f;
}

void display()
{
	 static uchar index;

	 P2 = P2&0x1f|0xe0;
	 P0 = 0xff;
	 P2 = P2&0x1f;

	 P2 = P2&0x1f|0xc0;
	 P0 = 1<<index;
	 P2 = P2&0x1f;

	 P2 = P2&0x1f|0xe0;
	 P0 = ~duan[disbuff[index]];
	 P2 = P2&0x1f;
	 
	 ++index;
	 index&= 0x07;
}

void  show_num()
{
	disbuff[0] = 11;
	disbuff[1] = 11;
	disbuff[2] = 11;
	disbuff[3] = 11;
	disbuff[4] = 11;
	disbuff[5] = adc_value/100;
	disbuff[6] = adc_value/10%10;
	disbuff[7] = adc_value%10;
}

void Timer0Init(void)		//2毫秒@12.000MHz
{
	AUXR |= 0x80;		//定时器时钟1T模式
	TMOD &= 0xF0;		//设置定时器模式
	TL0 = 0x40;		//设置定时初值
	TH0 = 0xA2;		//设置定时初值
	TF0 = 0;		//清除TF0标志
	TR0 = 1;		//定时器0开始计时
	ET0 = 1;
	EA = 1;
}

void Timer0() interrupt 1
{
	TL0 = 0x40;		//设置定时初值
	TH0 = 0xA2;	
	display();
}

void main()
{
	clzbuzz();
	Timer0Init();
	write_adc(0x03);//初始化通道0x03，获取电位器1的电压值
	while(1)
	{
		adc_value = read_adc(0x03);//读取电位器1的电压值	
		adc_value = adc_value*99/255.0f;//把电压值调整为0-100之间的数值
		show_num();
	}
}