How to read and write CAT24C32 using C51 microcontroller

#include

#include //My custom LCD1602 header file

/*---------------------------------------------------------------

24C32 can store 4K (1024*4) bytes (8 bits), so the maximum addressing address is 0x0FFF, and 24C32 is a slave.

----------------------------------------------------------------*/

#defineWriteDeviceAddress0x0A2 //Define the write address of the device in the I2C bus (Note: change according to the custom slave address interface)

#defineReadDviceAddress0x0A3 //Define the read address of the device in the I2C bus (Note: change according to the custom slave address interface)

sbitSCL=P0^4; //My 24C32 interface settings

sbitSDA=P3^7;

//2us delay subroutine

voiddelay_2us（uchari）

{

while（--i）;

}

// Start the bus

voidStart（）

{

SDA=1;

SCL=1;

delay_2us（1）;

SDA=0;

delay_2us（1）;

SCL=0;

}

//End the bus

voidStop（）

{

SDA=0;

SCL=1;

delay_2us（1）;

SDA=1;

delay_2us（1）;

SDA=0;

SCL=0;

}

//Send the response signal

//voidMACK（）

//{

//SDA=0;

//SCL=1;

//delay_2us（1）;

//SCL=0;

//SDA=1;

//}

//Send a no-acknowledge bit signal

voidMNACK（）

{

SDA=1;

SCL=1;

delay_2us（1）;

SCL=0;

SDA=0;

}

//Detect slave response signal

bitCACK（）

{

bitflag;

SDA=1;

SCL=1;

delay_2us（1）;

flag=SDA;

SCL=0;

return（flag）;

}

/*--------------------------------------------------------------------------

//Write 8 bits to 24C32

---------------------------------------------------------------------------*/

Write8Bit（ucharinput）

{

uchartemp;

for（temp=0;temp《8;temp++）

{

SDA=（bit）（input&0x80）;

SCL=1;

delay_2us（1）;

SCL=0;

input=input《《1;

}

}

/*--------------------------------------------------------------------------

//Write a byte into 24C32

---------------------------------------------------------------------------*/

voidWrite24C32（ucharch，uintaddress）

{

Start（）;

Write8Bit（WriteDeviceAddress）;

while（CACK（））;

Write8Bit(address/256); (Note: the address is sent twice, with the high bit first!)

while（CACK（））;

Write8Bit（address%256）;

while（CACK（））;

Write8Bit（ch）;

while（CACK（））;

Stop（）;

}

/*--------------------------------------------------------------------------

//Read 8 bits from 24C32

---------------------------------------------------------------------------*/

ucharRead8Bit（）

{

unsignedchartemp，rbyte=0;

for（temp=0;temp《8;temp++）

{

SDA=1;

SCL=1;

rbyte=rbyte|（（unsignedchar）（SDA））;

if (temp < 7) // Note: only shift left 7 times

{

rbyte=rbyte《《1;

}

SCL=0;

}

return（rbyte）;

}

/*--------------------------------------------------------------------------

Read 1 byte from 24c32

---------------------------------------------------------------------------*/

ucharRead24C32（uintaddress）

{

ucharch;

Start（）;

Write8Bit（WriteDeviceAddress）;

while（CACK（））;

Write8Bit（address/256）;

while（CACK（））;

Write8Bit（address%256）;

while（CACK（））;

Start（）;

Write8Bit（ReadDviceAddress）;

while（CACK（））;

ch=Read8Bit（）;

MNACK（）;

Stop（）;

return（ch）;

}

/*--------------------------------------------------------------------------

Main function

---------------------------------------------------------------------------*/

voidmain(void) //main program

{

high rise;

LCD1602_init(); //1602 initialization

Write24C32 ('8', 0x01FF); // write '5' into 0x1FF

LCD1602_puts（0，0，“24C32W_TestOK！”）;

newchar = Read24C32 (0x01FF); // Receive data from 0x1FF

LCD1602_puts（0，1，“ReadValue=”）;

LCD1602_puts（10，1，newchar）;

while（1）;

}