蓝桥杯单片机必备知识-----(3)pcf8591–ADC
IIC.H中需要添加的代码
unsigned char init_pcf8591(void);
unsigned char read_pcf8591(void);
IIC.C中需要添加的代码
void init_pcf8591(void)
{
IIC_Start();
IIC_SendByte(0x90);
IIC_WaitAck();
IIC_SendByte(0x03); //ADC通道3
IIC_WaitAck();
IIC_Stop();
}
unsigned char adc_pcf8591(void)
{
unsigned char temp;
IIC_Start(); //总线启动条件
IIC_SendByte(0x90); //通过I2C总线发送数据
IIC_WaitAck(); //等待应答
IIC_SendByte(add); //通过I2C总线发送数据
IIC_WaitAck(); //等待应答
IIC_Stop(); //总线停止条件
IIC_Start(); //总线启动条件
IIC_SendByte(0x91); //通过I2C总线发送数据
IIC_WaitAck(); //等待应答
temp=IIC_RecByte(); //从I2C总线上接收数据
IIC_Stop(); //总线停止条件
return temp; //返回值
}
主函数
void main()
{
cls_buzz(); //关闭buzz
AUXR = 0x80; //将定时器0设置为12分频，定时器时钟1T模式
TMOD = 0x30; //屏蔽定时器1，设置定时器0为定时模式
TL0 = 0xcd; //填入初始值，设置时间为1ms
TH0 = 0xd4;
TF0 = 0; //清除TF0标志
TR0 = 1; //定时器0开始计时
ET0 = 1; //允许定时器0中断
EA = 1; //开启CPU总中断允许
init_pcf8591(); //添加pcf8591初始化函数
while(1)
{
if(adc_flag)//读取ADC数值的标志位
{
adc_flag = 0;
adc_value = read_pcf8591(); //读取ADC
}
}
}
中断函数
void time0(void) interrupt 1
{
if(++intr == 50) //50ms读取一次ADC的值
{
intr = 0;
adc_flag = 1;
}
display();
}
测试：
明天放图
IIC.H
#ifndef __IIC_H
#define __IIC_H
void IIC_Start(void);
void IIC_Stop(void);
bit IIC_WaitAck(void);
void IIC_SendAck(bit ackbit);
void IIC_SendByte(unsigned char byt);
unsigned char IIC_RecByte(void);
unsigned char init_pcf8591(void);
unsigned char read_pcf8591(void);
#endif
IIC.C
#include "reg52.h"
#include "intrins.h"
#define DELAY_TIME 5
#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 */
void IIC_Delay(unsigned char i)
{
do{
_nop_();}
while(i--);
}
//总线启动条件
void IIC_Start(void)
{
SDA = 1;
SCL = 1;
IIC_Delay(DELAY_TIME);
SDA = 0;
IIC_Delay(DELAY_TIME);
SCL = 0;
}
//总线停止条件
void IIC_Stop(void)
{
SDA = 0;
SCL = 1;
IIC_Delay(DELAY_TIME);
SDA = 1;
IIC_Delay(DELAY_TIME);
}
//发送应答
void IIC_SendAck(bit ackbit)
{
SCL = 0;
SDA = ackbit; // 0：应答，1：非应答
IIC_Delay(DELAY_TIME);
SCL = 1;
IIC_Delay(DELAY_TIME);
SCL = 0;
SDA = 1;
IIC_Delay(DELAY_TIME);
}
//等待应答
bit IIC_WaitAck(void)
{
bit ackbit;
SCL = 1;
IIC_Delay(DELAY_TIME);
ackbit = SDA;
SCL = 0;
IIC_Delay(DELAY_TIME);
return ackbit;
}
//通过I2C总线发送数据
void IIC_SendByte(unsigned char byt)
{
unsigned char i;
for(i=0; i<8; i++)
{
SCL = 0;
IIC_Delay(DELAY_TIME);
if(byt & 0x80) SDA = 1;
else SDA = 0;
IIC_Delay(DELAY_TIME);
SCL = 1;
byt <<= 1;
IIC_Delay(DELAY_TIME);
}
SCL = 0;
}
//从I2C总线上接收数据
unsigned char IIC_RecByte(void)
{
unsigned char i, da;
for(i=0; i<8; i++)
{
SCL = 1;
IIC_Delay(DELAY_TIME);
da <<= 1;
if(SDA) da |= 1;
SCL = 0;
IIC_Delay(DELAY_TIME);
}
return da;
}
void operate_delay(unsigned char t)
{
unsigned char i;
while(t--)
{
for(i = 0;i<112 ; i++);
}
}
void init_pcf8591(void)
{
IIC_Start();
IIC_SendByte(0x90);
IIC_WaitAck();
IIC_SendByte(0x03); //ADC通道3
IIC_WaitAck();
IIC_Stop();
operate_delay(10);
}
unsigned char read_pcf8591(void)
{
unsigned char temp;
IIC_Start();
IIC_SendByte(0x91);
IIC_WaitAck();
temp = IIC_RecByte();
IIC_SendAck(1);
IIC_Stop();
return temp;
}
main.C
#include <stc15f2k60s2.h>
#include "iic.h"
#define uchar unsigned char
#define uint unsigned int
code unsigned char tab[] = {
0xc0,0xf9,0xa4,0xb0,0x99,0x92,0x82,0xf8,0x80,0x90,0xff};
uchar dspbuf[8] = {
10,10,10,10,10,10,10,10};
uchar adc_flag;
uchar intr = 0;
uchar adc_value;
void display();
void load();
void cls_buzz()
{
P2 = (P2 & 0x1f) | 0xa0;
P0 = 0x00;
P2 = 0x1f;
P2 = (P2 & 0x1f) | 0x80;
P0 = 0xff;
P2 = 0x1f;
}
void main()
{
cls_buzz();
AUXR = 0x80;
TMOD = 0x00;
TH0 = 0xcd;
TL0 = 0xd4;
TF0 = 0;
TR0 = 1;
ET0 = 1;
EA = 1;
init_pcf8591();
while(1)
{
if(adc_flag)
{
adc_flag = 0;
adc_value = read_pcf8591();
}
}
}
void time0(void) interrupt 1
{
if(++intr == 50)
{
intr = 0;
adc_flag = 1;
}
display();
}
void load()
{
(adc_value>= 100)?(dspbuf[5] = adc_value/100):(dspbuf[5] = 10);
(adc_value>=10)?(dspbuf[6] = adc_value%100/10):(dspbuf[6] = 10);
dspbuf[7] = adc_value%10;
}
void display()
{
static unsigned char dspcom = 0;
load();
P2 = (P2 & 0x1f) | 0xe0;
P0 = 0xff;
P2 = 0x1f;
P2 = (P2 & 0x1f) | 0xc0;
P0 = 1<<dspcom;
P2 = 0x1f;
P2 = (P2 & 0x1f) | 0xe0;
P0 = tab[dspbuf[dspcom]];
P2 = 0x1f;
if(++dspcom == 8) dspcom = 0;
}