Program for controlling AT24C04 by microcontroller STC12C5A60S2 (C language)

/**************************************

Main chip: STC12C5A60S2 (1T)
Working frequency: 12.000MHz
**************************************** /

#include"REG51.H"
#include"INTRINS.H"

typedefunsignedcharBYTE;
typedefunsignedshortWORD;

sbitSCL=P3^4;//clock of AT24C04
sbitSDA=P3^5;//data of AT24C04

BYTEBUF[16];//data buffer

BYTEcodeTESTDATA[]=
{
0x00,0x11,0x22,0x33,0x44 ,0x55,0x66,0x77,
0x88,0x99,0xAA,0xBB,0xCC,0xDD,0xEE,0xFF
};

voidDelay5us();
voidDelay5ms();
voidAT24C04_Start();
voidAT24C04_Stop();
voidAT24C04_SenDACK(bitack);
bitAT24C04_Rec vACK();
voidAT24C04_SendByte (BYTEdat);
BYTEAT24C04_RecvByte();
voidAT24C04_ReadPage();
voidAT24C04_WritePage();

voidmain()
{
AT24C04_WritePage();
Delay5ms();
AT24C04_ReadPage();

while(1);

}

/*********** ***************************
Write 1 page (16 bytes) of data to AT24C04
and write the 16 test data starting from TESTDATA as the device 00~0F address
******************************************/
voidAT24C04_WritePage()
{
BYTEi;

AT24C04_Start();//Start signal
AT24C04_SendByte(0xa0);//Send device address + write signal
AT24C04_SendByte(0x00);//Send storage unit address

for （i=0; i《16; i++）

{

BUF［i］ = AT24C04_RecvByte（）;

if （i == 15）

{

AT24C04_SendACK(1); //The last data needs to be NAK

}

else

{

AT24C04_SendACK(0); //Response ACK

}

}

AT24C04_Stop(); //Stop signal

}

/**************************************

Delay 5 microseconds (STC12C5A60S2@12M)

Different working environments require adjusting this function

This delay function is calculated using 1T instruction cycle, which is different from the traditional 12T MCU.

**************************************/

void Delay5us（）

{

BYTE n = 4;

while （n--）

{

_nop_（）;

_nop_（）;

}

}

/**************************************

Delay 5 milliseconds (STC12C5A60S2@12M)

Different working environments require adjusting this function

This delay function is calculated using 1T instruction cycle, which is different from the traditional 12T MCU.

**************************************/

void Delay5ms（）

{

BE n = 2500;

while （n--）

{

_nop_（）;

_nop_（）;

_nop_（）;

_nop_（）;

_nop_（）;

}

}

/**************************************

start signal

**************************************/

void AT24C04_Start（）

{

SDA = 1; //Pull the data line high

SCL = 1; //pull the clock line high

Delay5us(); //Delay

SDA = 0; //Generate falling edge

Delay5us(); //Delay

SCL = 0; //pull the clock line low

}

/**************************************

stop signal

**************************************/

void AT24C04_Stop（）

{

SDA = 0; //Pull the data line low

SCL = 1; //pull the clock line high

Delay5us(); //Delay

SDA = 1; //Generate rising edge

Delay5us(); //Delay

}

/**************************************

Send acknowledgment signal

Entry parameters: ack (0:ACK 1:NAK)

**************************************/

void AT24C04_SendACK（bit ack）

{

SDA = ack; //Write response signal

SCL = 1; //pull the clock line high

Delay5us(); //Delay

SCL = 0; //pull the clock line low

Delay5us(); //Delay

}

/**************************************

receive response signal

**************************************/

bit AT24C04_RecvACK（）

{

SCL = 1; //pull the clock line high

Delay5us(); //Delay

CY = SDA; //Read response signal

SCL = 0; //pull the clock line low

Delay5us(); //Delay

return CY;

}

/**************************************

Send one byte of data to the IIC bus

**************************************/

void AT24C04_SendByte（BYTE dat）

{

SWITCH in;

for (i=0; i<8; i++) //8-bit counter

{

dat <<= 1; //Move out the highest bit of data

SDA = CY; //Send data port

SCL = 1; //pull the clock line high

Delay5us(); //Delay

SCL = 0; //pull the clock line low

Delay5us(); //Delay

}

AT24C04_RecvACK（）;

}

/**************************************

Receive one byte of data from the IIC bus

**************************************/

BYTE AT24C04_RecvByte（）

{

SWITCH in;

BYTE dat = 0;

SDA = 1; //Enable internal pull-up and prepare to read data

for (i=0; i<8; i++) //8-bit counter

{

that <<= 1;

SCL = 1; //pull the clock line high

Delay5us(); //Delay

dat |= SDA; //Read data

SCL = 0; //pull the clock line low

Delay5us(); //Delay

}

return that;

}