For LCD: For I2C : For EEPROM: 
8051 interfacing with EEPROM
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#include "Includes.h"
// Main function
void main()
{
unsigned char RxByte = 0;
unsigned char TxArray[4] = { '1', '2', '3', '4' };
unsigned char RxArray[4] = { 0 };
// Initialize LCD
InitLCD();
// Initialize i2c pins
InitI2C();
// Write '5' at 0x0001 address in EEPROM
Write_Byte_To_24LC64_EEPROM(0x0001, '5');
// Read from 0x0001 address from EEPROM
RxByte = Read_Byte_From_24LC64_EEPROM(0x0001);
// Write 4 bytes of TxArray starting from 0x0020 address in EEPROM
Write_Page_To_24LC64_EEPROM(0x0020, TxArray, 4);
// Read 4 bytes starting from 0x0020 address in EEPROM, save these bytes into RxArray
Read_Bytes_From_24LC64_EEPROM(0x0020, RxArray, 4);
// Display received values on LCD display
WriteDataToLCD(RxArray[0]);
WriteDataToLCD(RxArray[1]);
WriteDataToLCD(RxArray[2]);
WriteDataToLCD(RxArray[3]);
WriteDataToLCD(RxByte);
while(1)
{
}
}
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#include "Includes.h"
void ToggleEpinOfLCD(void)
{
E = 1; // Give a pulse on E pin
__delay_us(E_Delay); // so that LCD can latch the
E = 0; // data from data bus
__delay_us(E_Delay);
}
void WriteDataToLCD(char t)
{
RS = 1; // This is data
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= (t&0xF0); // Write Upper nibble of data
ToggleEpinOfLCD(); // Toggle E pin to send data
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= ((t<<4)&0xF0);// Write Lower nibble of data
ToggleEpinOfLCD(); // Toggle E pin to send data
}
void WriteCommandToLCD(int z)
{
RS = 0; // This is command
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= (z&0xF0); // Write Upper nibble of data
ToggleEpinOfLCD(); // Toggle E pin to send data
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= ((z<<4)&0xF0);// Write Lower nibble of data
ToggleEpinOfLCD(); // Toggle E pin to send data
}
void InitLCD(void)
{
RS = 0; // Make pin zero
E = 0; // Make Pin zero
///////////// Reset process from datasheet /////////
__delay_us(15000);
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= 0x30; // Write 0x3
ToggleEpinOfLCD(); // Toggle E pin to send data
__delay_us(4500);
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= 0x30; // Write 0x3
ToggleEpinOfLCD(); // Toggle E pin to send data
__delay_us(300);
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= 0x30; // Write 0x3
ToggleEpinOfLCD(); // Toggle E pin to send data
__delay_us(650);
P2 &= 0x0F; // Make P2.4 to P2.7 zero
P2 |= 0x20; // Write 0x2
ToggleEpinOfLCD(); // Toggle E pin to send data
__delay_us(650);
/////////////////////////////////////////////////////
WriteCommandToLCD(0x28); //function set
WriteCommandToLCD(0x0c); //display on,cursor off,blink off
WriteCommandToLCD(0x01); //clear display
WriteCommandToLCD(0x06); //entry mode, set increment
}
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#include "Includes.h"
// Function Purpose: Produce approximate delay in given uSecs.
void __delay_us(unsigned int d)
{
unsigned int i, limit;
limit = d/15;
for(i=0;i<limit;i++);
}
// Function Purpose: Set initial values of SCK and SDA pins
void InitI2C(void)
{
// Make SDA and SCK pins input initially
SDA = 1;
SCK = 1;
}
// Function Purpose: I2C_Start sends start bit sequence
void I2C_Start(void)
{
Set_SCK_High; // Make SCK pin high
Set_SDA_High; // Make SDA pin High
__delay_us(HalfBitDelay); // Half bit delay
Set_SDA_Low; // Make SDA Low
__delay_us(HalfBitDelay); // Half bit delay
}
// Function Purpose: I2C_ReStart sends start bit sequence
void I2C_ReStart(void)
{
Set_SCK_Low; // Make SCK pin low
__delay_us(HalfBitDelay/2); // Data pin should change it's value,
// when it is confirm that SCK is low
Set_SDA_High; // Make SDA pin High
__delay_us(HalfBitDelay/2); // 1/4 bit delay
Set_SCK_High; // Make SCK pin high
__delay_us(HalfBitDelay/2); // 1/4 bit delay
Set_SDA_Low; // Make SDA Low
__delay_us(HalfBitDelay/2); // 1/4 bit delay
}
//Function : I2C_Stop sends stop bit sequence
void I2C_Stop(void)
{
Set_SCK_Low; // Make SCK pin low
__delay_us(HalfBitDelay/2); // Data pin should change it's value,
// when it is confirm that SCK is low
Set_SDA_Low; // Make SDA pin low
__delay_us(HalfBitDelay/2); // 1/4 bit delay
Set_SCK_High; // Make SCK pin high
__delay_us(HalfBitDelay/2); // 1/4 bit delay
Set_SDA_High; // Make SDA high
__delay_us(HalfBitDelay/2); // 1/4 bit delay
}
//Function : I2C_Send_ACK sends ACK bit sequence
void I2C_Send_ACK(void)
{
Set_SCK_Low; // Make SCK pin low
__delay_us(HalfBitDelay/2); // Data pin should change it's value,
// when it is confirm that SCK is low
Set_SDA_Low; // Make SDA Low
__delay_us(HalfBitDelay/2); // 1/4 bit delay
Set_SCK_High; // Make SCK pin high
__delay_us(HalfBitDelay); // Half bit delay
}
//Function : I2C_Send_NACK sends NACK bit sequence
void I2C_Send_NACK(void)
{
Set_SCK_Low; // Make SCK pin low
__delay_us(HalfBitDelay/2); // Data pin should change it's value,
// when it is confirm that SCK is low
Set_SDA_High; // Make SDA high
__delay_us(HalfBitDelay/2); // 1/4 bit delay
Set_SCK_High; // Make SCK pin high
__delay_us(HalfBitDelay); // Half bit delay
}
// Function Purpose: I2C_Write_Byte transfers one byte
bit I2C_Write_Byte(unsigned char Byte)
{
unsigned char i; // Variable to be used in for loop
for(i=0;i<8;i++) // Repeat for every bit
{
Set_SCK_Low; // Make SCK pin low
__delay_us(HalfBitDelay/2); // Data pin should change it's value,
// when it is confirm that SCK is low
if((Byte<<i)&0x80) // Place data bit value on SDA pin
Set_SDA_High; // If bit is high, make SDA high
else // Data is transferred MSB first
Set_SDA_Low; // If bit is low, make SDA low
__delay_us(HalfBitDelay/2); // Toggle SCK pin
Set_SCK_High; // So that slave can
__delay_us(HalfBitDelay); // latch data bit
}
// Get ACK from slave
Set_SCK_Low;
Set_SDA_High;
__delay_us(HalfBitDelay);
Set_SCK_High;
__delay_us(HalfBitDelay);
return SDA;
}
// Function Purpose: I2C_Read_Byte reads one byte
unsigned char I2C_Read_Byte(void)
{
unsigned char i, d, RxData = 0;
for(i=0;i<8;i++)
{
Set_SCK_Low; // Make SCK pin low
Set_SDA_High; // Don't drive SDA
__delay_us(HalfBitDelay); // Half bit delay
Set_SCK_High; // Make SCK pin high
__delay_us(HalfBitDelay/2); // 1/4 bit delay
d = SDA; // Capture Received Bit
RxData = RxData|(d<<(7-i)); // Copy it in RxData
__delay_us(HalfBitDelay/2); // 1/4 bit delay
}
return RxData; // Return received byte
}
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#include "Includes.h"
// Function Purpose: Write_Byte_To_24LC64_EEPROM writes a single byte on given address
// Address can have any value fromm 0 to 0x1FFF, and DataByte can have a value of 0 to 0xFF.
void Write_Byte_To_24LC64_EEPROM(unsigned int Address, unsigned char DataByte)
{
I2C_Start(); // Start i2c communication
// Send i2c address of 24LC64 with write command
while(I2C_Write_Byte(Device_Address_24LC64_EEPROM + 0) == 1)// Wait until device is free
{ I2C_Start(); }
I2C_Write_Byte(Address>>8); // Write Address upper byte
I2C_Write_Byte((unsigned char)Address); // Write Address lower byte
I2C_Write_Byte(DataByte); // Write data byte
I2C_Stop(); // Stop i2c communication
}
// Function Purpose: Read_Byte_From_24LC64_EEPROM reads a single byte from given address
// Address can have any value fromm 0 to 0x1FFF.
unsigned char Read_Byte_From_24LC64_EEPROM(unsigned int Address)
{
unsigned char Byte = 0; // Variable to store Received byte
I2C_Start(); // Start i2c communication
// Send i2c address of 24LC64 with write command
while(I2C_Write_Byte(Device_Address_24LC64_EEPROM + 0) == 1)// Wait until device is free
{ I2C_Start(); }
I2C_Write_Byte(Address>>8); // Write Address upper byte
I2C_Write_Byte((unsigned char)Address); // Write Address lower byte
I2C_ReStart(); // Restart i2c
// Send i2c address of 24LC64 EEPROM with read command
I2C_Write_Byte(Device_Address_24LC64_EEPROM + 1);
Byte = I2C_Read_Byte(); // Read byte from EEPROM
// Make SCK low, so that slave can stop driving SDA pin
// Send a NACK to indiacate single byte read is complete
I2C_Send_NACK();
// Send start bit and then stop bit to stop transmission
Set_SDA_Low; // Make SDA Low
__delay_us(HalfBitDelay); // Half bit delay
Set_SDA_High; // Make SDA high
__delay_us(HalfBitDelay); // Half bit delay
return Byte; // Return the byte received from 24LC64 EEPROM
}
// Function Purpose: Write_Page_To_24LC64_EEPROM writes a page on given address
// Address can have value 0, 32, 64, .... only and pData is pointer to the array
// containing NoOfBytes bytes in it. NoOfBytes can have a value from 1 to 32 only.
void Write_Page_To_24LC64_EEPROM(unsigned int Address,unsigned char* pData,unsigned char NoOfBytes)
{
unsigned int i;
I2C_Start(); // Start i2c communication
// Send i2c address of 24LC64 with write command
while(I2C_Write_Byte(Device_Address_24LC64_EEPROM + 0) == 1)// Wait until device is free
{ I2C_Start(); }
I2C_Write_Byte(Address>>8); // Write Address upper byte
I2C_Write_Byte((unsigned char)Address); // Write Address lower byte
for(i=0;i<NoOfBytes;i++) // Write NoOfBytes
I2C_Write_Byte(pData[i]); // Write data byte
I2C_Stop(); // Stop i2c communication
}
// Function Purpose: Read_Bytes_From_24LC64_EEPROM reads a NoOfBytes bytes from given starting address.
// Address can have any value fromm 0 to 0x1FFF. Also, NoOfBytes can have any value 0 to 0x1FFF.
// Read bytes are returned in pData array.
void Read_Bytes_From_24LC64_EEPROM(unsigned int Address, unsigned char* pData, unsigned int NoOfBytes)
{
unsigned int i;
I2C_Start(); // Start i2c communication
// Send i2c address of 24LC64 with write command
while(I2C_Write_Byte(Device_Address_24LC64_EEPROM + 0) == 1)// Wait until device is free
{ I2C_Start(); }
I2C_Write_Byte(Address>>8); // Write Address upper byte
I2C_Write_Byte((unsigned char)Address); // Write Address lower byte
I2C_ReStart(); // Restart i2c
// Send i2c address of 24LC64 EEPROM with read command
I2C_Write_Byte(Device_Address_24LC64_EEPROM + 1);
pData[0] = I2C_Read_Byte(); // Read First byte from EEPROM
for(i=1;i<NoOfBytes;i++) // Read NoOfBytes
{
I2C_Send_ACK(); // Give Ack to slave to start receiving next byte
pData[i] = I2C_Read_Byte(); // Read next byte from EEPROM
}
// Make SCK low, so that slave can stop driving SDA pin
// Send a NACK to indiacate read operation is complete
I2C_Send_NACK();
// Send start bit and then stop bit to stop transmission
Set_SDA_Low; // Make SDA Low
__delay_us(HalfBitDelay); // Half bit delay
Set_SDA_High; // Make SDA high
__delay_us(HalfBitDelay); // Half bit delay
}
