蓝桥杯单片机必备知识—–(4)pcf8591–DAC

蓝桥杯单片机必备知识—–(4)pcf8591–DAC

IIC.H文件中添加

dac_pcf8591(unsigned char dat)

IIC.C文件中添加

void dac_pcf8591(unsigned char dat)
{
   
	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(0x40);		//通过I2C总线发送数据
	IIC_WaitAck();			//等待应答
	
	IIC_SendByte(dat);
	IIC_WaitAck();
	IIC_Stop();
}

主函数 main.c中添加

dac_pcf8591(dac_value);

注：该ADC模块只能通过0~255来输出最大4.85V，显示时应该需要适当的转换

测试结果：（测试结果没有转换）

完整代码粘贴

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 adc_pcf8591(void);

void dac_pcf8591(unsigned char dat);

#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;    
}
//DAC
void dac_pcf8591(unsigned char dat)
{

IIC_Start();
IIC_SendByte(0x90);
IIC_WaitAck();
IIC_SendByte(0x40);
IIC_WaitAck();
IIC_SendByte(dat);
IIC_WaitAck();
IIC_Stop();
}
//ADC
void init_pcf8591()
{

IIC_Start();
IIC_SendByte(0x90);
IIC_WaitAck();
IIC_SendByte(0x03);
IIC_WaitAck();
IIC_Stop();
}
unsigned char adc_pcf8591()
{

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 uint unsigned int
#define uchar unsigned char
uchar 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,dac_value,adc_value;
uchar s6 = 0,s7 = 0;
void load();
void display();
void read_key();
void cls()
{

P2 = (P2 & 0x1f) | 0x80;
P0 = 0xff;
P2 = 0x1f;
P2 = (P2 & 0x1f) | 0xa0;
P0 = 0x00;
P2 = 0x1f;
}
void main()
{

cls();
AUXR = 0xc0;
TMOD = 0x00;
TL0 = 0xcd;
TH0 = 0xd4;
TR0 = 1;
ET0 = 1;
EA = 1;
init_pcf8591();
while(1)
{

if(adc_flag){
adc_value = adc_pcf8591();adc_flag = 0;}
read_key();
}
}
void time0() interrupt 1
{

static unsigned char intr = 0;
intr++;
if(intr = 50){
intr = 0; adc_flag = 1;}
display();
}
void load()
{

if(s7)
{

s7 = 0;
dac_value = 105.15; //2v
dac_pcf8591(dac_value);
}
if(s6)
{

s6= 0;
dac_value = 210.31; //4v
dac_pcf8591(dac_value);
}
dspbuf[1] = dac_value / 100;
dspbuf[2] = dac_value %100/10;
dspbuf[3] = dac_value %10;
dspbuf[5] = adc_value / 100;
dspbuf[6] = adc_value %100/10;
dspbuf[7] = adc_value %10;
}
void read_key()
{

static unsigned char state = 0;
uchar temp;
temp = P3 & 0x0f;
switch(state)
{

case 0:
{

if(P3 != 0x0f) state = 1;
}break;
case 1:
{

if(P3 != 0x0f)
{

switch(temp)
{

case 0x0e:{
s7= (s7 + 1) % 2; state = 2;}break;
case 0x0d:{
s6= (s6 + 1) % 2; state = 2;}break;
}
}
else state = 0;
}break;
case 2:
{

if(P3 == 0xff) state = 0;
}break;
}
}
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;
}