LCD I2C Interfacing With PIC16f877A - microcontroller

Question

I am trying to interface an LCD using I2C but can't quite understand how to do it.
I found this example
Here's the code:
i2c.h:
/* File: I2C_LCD.h */
#define _XTAL_FREQ 16000000
#define I2C_BaudRate 100000
#define SCL_D TRISC3
#define SDA_D TRISC4
#define LCD_BACKLIGHT 0x08
#define LCD_NOBACKLIGHT 0x00
#define LCD_FIRST_ROW 0x80
#define LCD_SECOND_ROW 0xC0
#define LCD_THIRD_ROW 0x94
#define LCD_FOURTH_ROW 0xD4
#define LCD_CLEAR 0x01
#define LCD_RETURN_HOME 0x02
#define LCD_ENTRY_MODE_SET 0x04
#define LCD_CURSOR_OFF 0x0C
#define LCD_UNDERLINE_ON 0x0E
#define LCD_BLINK_CURSOR_ON 0x0F
#define LCD_MOVE_CURSOR_LEFT 0x10
#define LCD_MOVE_CURSOR_RIGHT 0x14
#define LCD_TURN_ON 0x0C
#define LCD_TURN_OFF 0x08
#define LCD_SHIFT_LEFT 0x18
#define LCD_SHIFT_RIGHT 0x1E
#define LCD_TYPE 2 // 0 -> 5x7 | 1 -> 5x10 | 2 -> 2 lines
//-----------[ Functions' Prototypes ]--------------
//---[ I2C Routines ]---
void I2C__Init();
void I2C__Wait();
void I2C__Start();
void I2C__RepeatedStart();
void I2C__Stop();
void I2C_ACK();
void I2C_NACK();
unsigned char I2C__Write(unsigned char data);
unsigned char I2C_Read_Byte(void);
//---[ LCD Routines ]---
void LCD_Init(unsigned char I2C_Add);
void IO_Expander_Write(unsigned char Data);
void LCD_Write_4Bit(unsigned char Nibble);
void LCD_CMD(unsigned char CMD);
void LCD_Set_Cursor(unsigned char ROW, unsigned char COL);
void LCD_Write_Char(char);
void LCD_Write_String(char*);
void Backlight();
void noBacklight();
void LCD_SR();
void LCD_SL();
void LCD_Clear();
I2c.c
#include <xc.h>
#include "I2C.h"
unsigned char RS, i2c_add, BackLight_State = LCD_BACKLIGHT;
//---------------[ I2C Routines ]-------------------
//--------------------------------------------------
void I2C__Init()
{
SSPCON = 0x28;
SSPCON2 = 0x00;
SSPSTAT = 0x00;
SSPADD = ((_XTAL_FREQ/4)/I2C_BaudRate) - 1;
SCL_D = 1;
SDA_D = 1;
}
void I2C__Wait()
{
while ((SSPSTAT & 0x04) || (SSPCON2 & 0x1F));
}
void I2C__Start()
{
I2C__Wait();
SEN = 1;
}
void I2C__RepeatedStart()
{
I2C__Wait();
RSEN = 1;
}
void I2C__Stop()
{
I2C__Wait();
PEN = 1;
}
void I2C_ACK(void)
{
ACKDT = 0; // 0 -> ACK
I2C__Wait();
ACKEN = 1; // Send ACK
}
void I2C_NACK(void)
{
ACKDT = 1; // 1 -> NACK
I2C__Wait();
ACKEN = 1; // Send NACK
}
unsigned char I2C__Write(unsigned char data)
{
I2C__Wait();
SSPBUF = data;
while(!SSPIF); // Wait Until Completion
SSPIF = 0;
return ACKSTAT;
}
unsigned char I2C_Read_Byte(void)
{
//---[ Receive & Return A Byte ]---
I2C__Wait();
RCEN = 1; // Enable & Start Reception
while(!SSPIF); // Wait Until Completion
SSPIF = 0; // Clear The Interrupt Flag Bit
I2C__Wait();
return SSPBUF; // Return The Received Byte
}
//======================================================
//---------------[ LCD Routines ]----------------
//------------------------------------------------------
void LCD_Init(unsigned char I2C_Add)
{
i2c_add = I2C_Add;
IO_Expander_Write(0x00);
__delay_ms(30);
LCD_CMD(0x03);
__delay_ms(5);
LCD_CMD(0x03);
__delay_ms(5);
LCD_CMD(0x03);
__delay_ms(5);
LCD_CMD(LCD_RETURN_HOME);
__delay_ms(5);
LCD_CMD(0x20 | (LCD_TYPE << 2));
__delay_ms(50);
LCD_CMD(LCD_TURN_ON);
__delay_ms(50);
LCD_CMD(LCD_CLEAR);
__delay_ms(50);
LCD_CMD(LCD_ENTRY_MODE_SET | LCD_RETURN_HOME);
__delay_ms(50);
}
void IO_Expander_Write(unsigned char Data)
{
I2C__Start();
I2C__Write(i2c_add);
I2C__Write(Data | BackLight_State);
I2C__Stop();
}
void LCD_Write_4Bit(unsigned char Nibble)
{
// Get The RS Value To LSB OF Data
Nibble |= RS;
IO_Expander_Write(Nibble | 0x04);
IO_Expander_Write(Nibble & 0xFB);
__delay_us(50);
}
void LCD_CMD(unsigned char CMD)
{
RS = 0; // Command Register Select
LCD_Write_4Bit(CMD & 0xF0);
LCD_Write_4Bit((CMD << 4) & 0xF0);
}
void LCD_Write_Char(char Data)
{
RS = 1; // Data Register Select
LCD_Write_4Bit(Data & 0xF0);
LCD_Write_4Bit((Data << 4) & 0xF0);
}
void LCD_Write_String(char* Str)
{
for(int i=0; Str[i]!='\0'; i++)
LCD_Write_Char(Str[i]);
}
void LCD_Set_Cursor(unsigned char ROW, unsigned char COL)
{
switch(ROW)
{
case 2:
LCD_CMD(0xC0 + COL-1);
break;
case 3:
LCD_CMD(0x94 + COL-1);
break;
case 4:
LCD_CMD(0xD4 + COL-1);
break;
// Case 1
default:
LCD_CMD(0x80 + COL-1);
}
}
void Backlight()
{
BackLight_State = LCD_BACKLIGHT;
IO_Expander_Write(0);
}
void noBacklight()
{
BackLight_State = LCD_NOBACKLIGHT;
IO_Expander_Write(0);
}
void LCD_SL()
{
LCD_CMD(0x18);
__delay_us(40);
}
void LCD_SR()
{
LCD_CMD(0x1C);
__delay_us(40);
}
void LCD_Clear()
{
LCD_CMD(0x01);
__delay_us(40);
}
main.c:
#include "I2C.h"
void main(void) {
I2C__Init();
LCD_Init(0x4E); // Initialize LCD module with I2C address = 0x4E
LCD_Set_Cursor(1, 1);
LCD_Write_String(" Welcome To ");
LCD_Set_Cursor(2, 1);
LCD_Write_String(" MicroDigiSoft ");
delay_ms(2500);
while(1)
{
}
return;
}
But I get these Errors:
Screenshot of Error
Screenshot of Error
I am using MikroC and one thing to note is that I have included the system libraries Lcd and Lcd Constants.
How can I fix these errors, and are there any examples of interfacing LCD I2C with microcontrollers apart from this?

Answer 1

You must import the I2C system libray in the the MikroC Library Manager, at the right panel. See the attached image: