TEL:0086 15161516705

Documents

Your current location:Home > Documents > Tech-Support > detail
IIC Sample Code
Time: 2021.02.02

#include <reg52.h>
#include <math.h>
#define DELAY_TIME 600
#define TRUE 1
#define FALSE 0
#define uchar unsigned char
#define uint unsigned int
 
//--------------define IIC SCL,SDA port------------------------------ 

sbit SCL = P1 ^ 7;  
sbit SDA = P1 ^ 6;  

//-----------------define Max7219 port---------------------------

sbit Max7219_pinCLK = P2 ^ 2;  
sbit Max7219_pinCS = P2 ^ 1;
sbit Max7219_pinDIN = P2 ^ 0;

//-------------delay time_us-------------------------------
void DELAY(uint t)  
{
    while (t != 0)
        t--;
}

//-------------IIC START CONDITION-------------------------------
void I2C_Start(void) 
{
    SDA = 1;              //SDA output high
 DELAY(DELAY_TIME);
    SCL = 1;
    DELAY(DELAY_TIME);    //SCL output high
    SDA = 0;
    DELAY(DELAY_TIME);
    SCL = 0;
    DELAY(DELAY_TIME);
}
 
//-------------IIC STOP CONDITION-------------------------------
void I2C_Stop(void) 
{
    SDA = 0;              //SDA OUTPUT LOW
    DELAY(DELAY_TIME);
 SCL = 1;
    DELAY(DELAY_TIME);
    SDA = 1;
    DELAY(DELAY_TIME);
    SCL = 0;              //SCL OUTPUT LOW
    DELAY(DELAY_TIME);
}

//-------------IIC SEND DATA "0"-------------------------------
void SEND_0(void) 
{
    SDA = 0;
 DELAY(DELAY_TIME);
    SCL = 1;
    DELAY(DELAY_TIME);
    SCL = 0;
    DELAY(DELAY_TIME);
}

//-------------IIC SEND DATA "1"-------------------------------
void SEND_1(void)  
{

    SDA = 1;
    DELAY(DELAY_TIME);
    SCL = 1;
    DELAY(DELAY_TIME);
    SCL = 0;
    DELAY(DELAY_TIME);
}

//-------------Check SLAVE's Acknowledge -------------------------------
bit Check_Acknowledge(void)  
{

    SDA = 1;
    DELAY(DELAY_TIME);
    SCL = 1;
    DELAY(DELAY_TIME / 2);
    F0 = SDA;
    DELAY(DELAY_TIME / 2);
    SCL = 0;
    DELAY(DELAY_TIME);
    if (F0 == 1)
        return FALSE;
    return TRUE;
}

//-------------Write One Byte of Data -------------------------------
void WriteI2CByte(uchar b) reentrant  
{

    char i;
    for (i = 0; i < 8; i++)
        if ((b << i) & 0x80)
            SEND_1();
        else
            SEND_0();
}

//-------------Read One Byte of Data -------------------------------
uchar ReadI2CByte(void) reentrant   
{

    char b = 0, i;
    for (i = 0; i < 8; i++)
    {
        SDA = 1;
        DELAY(DELAY_TIME);
        SCL = 1;
        DELAY(DELAY_TIME);
        //DELAY(10);
        F0 = SDA;
        DELAY(DELAY_TIME);
        //DELAY(10);
        SCL = 0;
        if (F0 == 1)
        {
            b = b << 1;
            b = b | 0x01;
        }
        else
            b = b << 1;
    }
    return b;
}

//-------------write One Byte of Data,Data from MASTER to the SLAVER -------------------------------
//-------------SLAVER address bit:01101101-------------------------------
void Write_One_Byte(uchar addr, uchar thedata)  //Write "thedata" to the SLAVER's address of "addr"
{
    bit acktemp = 1;
    I2C_Start();                          //IIC START
    WriteI2CByte(0xDA);                   //IIC WRITE operation,SLAVER address bit:01101010
    acktemp = Check_Acknowledge();        //check the SLAVER
    WriteI2CByte(addr); /*address*/      
    acktemp = Check_Acknowledge();       
    WriteI2CByte(thedata); /*thedata*/   
    acktemp = Check_Acknowledge();
    I2C_Stop();                           //IIC STOP
}

//-------------Reaed One Byte of Data,Data from SLAVER to the MASTER -------------------------------
uchar Read_One_Byte(uchar addr)   
{
    bit acktemp = 1;
    uchar mydata;

    I2C_Start();                         
    WriteI2CByte(0xDA);                  
    acktemp = Check_Acknowledge();
    WriteI2CByte(addr); 
    acktemp = Check_Acknowledge();
    I2C_Start();
    WriteI2CByte(0xDB);                   //IIC READ operation
    acktemp = Check_Acknowledge();
    mydata = ReadI2CByte();
    acktemp = Check_Acknowledge();
    I2C_Stop();
    return mydata;
}
//-------------Delay_ms -------------------------------
void Delay_xms(uint x) 
{
    uint i, j;
    for (i = 0; i < x; i++)
        for (j = 0; j < 112; j++)
            ;
}

//-------------Write One Byte to the Max7219-------------
void Write_Max7219_byte(uchar DATA) 
{
    uchar i;
    Max7219_pinCS = 0;      //CS low effect
    for (i = 8; i >= 1; i--)
    {
        Max7219_pinCLK = 0;
        Max7219_pinDIN = DATA & 0x80; 
        DATA = DATA << 1;
        Max7219_pinCLK = 1;    //when pinCLK is high send the Data
    }
}
//-------------decide which address shows the Data-------------
void Write_Max7219(uchar address,uchar dat) 
{
    Max7219_pinCS = 0;
    Write_Max7219_byte(address); 
   Write_Max7219_byte(dat);
    Max7219_pinCS = 1;
}

//-------------MAX_7219 Initialization-------------
void Init_MAX7219(void)    
{
    Write_Max7219(0x09, 0xff);   //Decoded mode:BCD code
    Write_Max7219(0x0a, 0x03);   //Brightness
    Write_Max7219(0x0b, 0x07);   //Scan limit:8 digital display
    Write_Max7219(0x0c, 0x01);   //Power-Down modes :0,Normal code:1
    Write_Max7219(0x0f, 0x01);   //Display test:1;Test end,normal display:0
}


void main(void)
{
    uchar yali1, yali2, yali3,wendu1,wendu2;
    uchar temp_a5;
    long int ad,temp;
    long float pas;
    uchar dis[8];
    Init_MAX7219();    
    Delay_xms(1000); 
    Write_Max7219(0x0f, 0x00);    
    while (1)
    {

        temp_a5 = Read_One_Byte(0xA5);//Read ASIC Sys_config
        temp_a5 = temp_a5 & 0xFD;    //(Raw_data_on: 0: output calibrated data,namly the value in 0x06-0x0a)
        Write_One_Byte(0xA5, temp_a5); //Set ADC output calibrated Data
        Write_One_Byte(0x30, 0x0A); //indicate a combined conversion (once temperature conversion immediately followed by once sensor signal conversion)(wire measure order in 0x30,000:single temp. measure;001:single pressure. measure;010:combination:single pressure and temp. measurement;011:sleep mode(combined mode measurement at certain time intervals))
        while ((Read_One_Byte(0x30) & 0x08) > 0);  //Judge whether Data collection is over 
   
// -------------READ ADC output Data of Pressure  -------------
        yali1 = Read_One_Byte(0x06);
        yali2 = Read_One_Byte(0x07);
        yali3 = Read_One_Byte(0x08); 

        ad = yali1 * 65536 + yali2 * 256 + yali3;
   
// -------------READ ADC output Data of Temperature  ------------- 
        wendu1= Read_One_Byte(0x09);
        wendu2= Read_One_Byte(0x0a);
        temp=wendu1*256+wendu2;   
   
/*Conversion, the following is the conversion formula of 100*/
   
   if (ad > 8388608)         // >8388606 as negative value, handle at display end
        {
            pas = (ad - 16777216)/64/1000;      //unit is kpa
        }
        else
        {
            pas = ad/64/1000;                   //unit is kpa
        }
        if (pas < 0)
            pas = fabs(pas);
/*Display program with Max7219*/
        dis[0] = (long int)pas / 10000000;
        dis[1] = (long int)pas % 10000000 / 1000000;
        dis[2] = (long int)pas % 1000000 / 100000;
        dis[3] = (long int)pas % 100000 / 10000;
        dis[4] = (long int)pas % 10000 / 1000;
        dis[5] = (long int)pas % 1000 / 100;
        dis[6] = (long int)pas % 100 / 10;
        dis[7] = (long int)pas % 10;
        Write_Max7219(8, dis[0]);
        Write_Max7219(7, dis[1]);
        Write_Max7219(6, dis[2]);
        Write_Max7219(5, dis[3]);
        Write_Max7219(4, dis[4]);
        Write_Max7219(3, dis[5]);
        Write_Max7219(2, dis[6]);
        Write_Max7219(1, dis[7]);  
        Delay_xms(100);              //delay 100ms
    }
}

 
back
Scan wechat
Online
WhatsApp Skype QQ 15161516705
WeChat