STM32 simulates IIC reading and writing AT24CXX

I have only used 51 to make AT24C02 before. Later, I came into contact with models with larger capacity and found many inconsistencies with the previous ones. I have summarized them as follows.

In the previous blog, the basic driver code for STM32 to simulate IIC with IO port has been written. Now, combined with the data sheet, the functions mentioned in the previous blog are used to write the universal driver code for the entire AT24CXX series.

Let's first look at the Chinese manual of AT24CXX.

This is the write step.

The address information of the slave device mentioned above is shown in the figure below.

The slave device address bits of AT24CXX with different capacities are different, which is reflected in the differences in the basic read and write functions of the following devices.

Let's initialize AT24CXX first:

void AT24CXX_Init()

{

      IIC_Init();

}

Here you only need to initialize the IIC bus.

The following is the basic read and write function of AT24CXX

/*Read a data at the specified address of AT24CXX*/

u8 AT24CXX_ReadOneByte(u16 ReadAddr)
{      
 u8 temp=0;                          
    IIC_Start();  
 if(EE_TYPE>AT24C16)
 {
  IIC_Send_Byte(0XA0);    
  IIC_Wait_Ack();
  IIC_Send_Byte(ReadAddr>>8); //Send high address
  IIC_Wait_Ack();   
 }else IIC_Send_Byte(0XA0+((ReadAddr/256)<<1)); //This is important to understand

 IIC_Wait_Ack(); 
IIC_Send_Byte(ReadAddr%256); //Send low address
 IIC_Wait_Ack();     
 IIC_Start();        
 IIC_Send_Byte(0XA1); //Enter receiving mode
 IIC_Wait_Ack();  
 temp=IIC_Read_Byte(0);     
 IIC_Stop();     
 return temp;

The key point to understand is that the drivers for different models are realized by judging the EE_TYPE macro definition, that is, the selection of the model.

Similarly, the function to write data to the specified address is as follows:

void AT24CXX_WriteOneByte(u16 WriteAddr,u8 DataToWrite)
{                                
  IIC_Start();  
 if(EE_TYPE>AT24C16)
 {
  IIC_Send_Byte(0XA0);   
  IIC_Wait_Ack();
  IIC_Send_Byte(WriteAddr>>8);
  }else
 {
  IIC_Send_Byte(0XA0+((WriteAddr/256 ) <<1));    
 }  
 IIC_Wait_Ack();    
 IIC_Send_Byte(WriteAddr%256);   
 IIC_Wait_Ack();                    
 IIC_Send_Byte(DataToWrite);            
 IIC_Wait_Ack();            
IIC_Stop();
 delay_ms(10); //Note that there is a 10ms delay
}

At this point, the writing of the basic driver code is completed.