蓝桥杯之单片机学习（十九）——IIC协议（PCF8591、AT24C02）

文章目录

• ​​一、EEPROM、AD/DA电路​​
• ​​二、IIC协议介绍​​
• ​​三、PCF8591、AT24C02编程​​

• ​​3.1 PCF8591​​
• ​​3.2 AT24C02​​

• ​​四、练习​​
• ​​五、代码展示​​
• ​​一些事项​​

一、EEPROM、AD/DA电路

AD/DA电路：光敏电阻、电压分压

EEOROM：保存数据——数据写进和读出

二、IIC协议介绍

三、PCF8591、AT24C02编程

3.1 PCF8591

先写在读

1. 告诉ADC读哪个通道
2. 然后接收回来

3.2 AT24C02

四、练习

1. 编程实现PCF8591读取通道1和通道3的电压值:
2. 编程实现AT24C02的读写， 让0x55单元的数值每次上电自加1。

五、代码展示

#include "reg52.h"
#include "intrins.h"
#include "iic.h"
typedef unsigned char BYTE;
typedef unsigned int WORD;

unsigned char adc_table[3];
unsigned char volt_table[3];
unsigned char open_num_table[2];
//-----------------------------------------------

/* define constants */
#define FOSC 11059200L

#define T1MS (65536-FOSC/12/1000)   //1ms timer calculation method in 12T mode

/* define SFR */
sbit TEST_LED = P1^0;               //work LED, flash once per second

/* define variables */
WORD count;                         //1000 times counter

//-----------------------------------------------
unsigned char code T_display[]={0x3F,0x06,0x5B,0x4F,0x66,0x6D,0x7D,0x07,0x7F,0x6F};
unsigned char code T_COM[]={0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80}; 

/* Timer0 interrupt routine */
void tm0_isr() interrupt 1 using 1
{
        static char i;
    TL0 = T1MS;                     //reload timer0 low byte
    TH0 = T1MS >> 8;                //reload timer0 high byte
    if (count-- == 0)               //1ms * 1000 -> 1s
    {
                    count = 1;               //reset counter
            P2=0xe0;P0=~open_num_table[i];P2=0;
                    P2=0xc0;P0=T_COM[i];P2=0;
                    i++;
                    if(i==2) i=0;
    }
}

//-----------------------------------------------



void Delay2ms()     //@11.0592MHz
{
    unsigned char i, j;

    _nop_();
    i = 4;
    j = 146;
    do
    {
        while (--j);
    } while (--i);
}

/* main program */
void main()
{
        unsigned char adc_val;
      unsigned char open_num=0;
        float volt;
    
        open_num =read_24c02(0x55);
        write_24c02(0x55,++open_num);
        open_num_table[0]=T_display[open_num/10];
        open_num_table[1]=T_display[open_num%10];
    TMOD = 0x01;                    //set timer0 as mode1 (16-bit)
    TL0 = T1MS;                     //initial timer0 low byte
    TH0 = T1MS >> 8;                //initial timer0 high byte
    TR0 = 1;                        //timer0 start running
    ET0 = 1;                        //enable timer0 interrupt
    EA = 1;                         //open global interrupt switch
    count = 0;                      //initial counter
    
    write_adc(0x03); // ch3
    while(1)
    {
        EA=0;
        adc_val=read_adc(0x03);
        EA=1;
        volt=adc_val/255.0f*5;
        adc_table[0]=adc_val/100;//bai
        adc_table[1]=adc_val/10%10;//shi
        adc_table[2]=adc_val%10;
        
        volt_table[0]=T_display[(unsigned char)volt] | 0x80;
        volt_table[1]=T_display[(unsigned char)(volt*10)%10];
        volt_table[2]=T_display[(unsigned char)(volt*100)%10];
        Delay2ms();
    }
}

一些事项

PCF8591的通道1是光敏电阻，通道3是ADC转换
24C02与EEPROM可以掉电保存