PIC18F4520 – Interfacing LCD

Here PIC18F4520 Mini Development Board is interfaced with a LCD module (2×16) operating at 5V. The voltage at the third pin of the LCD used to adjusting contrast. Control lines (RS, R/W ,E) are connected to port pins (RS)RC0, (E)RC1 and data lines (D0-D7) to port pins RD0-RD7 where R/W is GND. For reliable Performance, LCD has to be initialized. On powering microcontroller send initialization commands to LCD for better working. The sample code below gives LCD display output ” RhydoLABZ ” in line 1 and “Dev Board” in line 2 .

Note: In default we may work out LCD in 8bit mode (jumpers are shorted from RD0 to RD3), where as if the jumpers are left open then LCD can be operated in 4 bit mode.

Schematic

Sample Code (8-bit)

/*************************************************************************
                           HEADER FILES
**************************************************************************/
#include<pic18.h>                 

/*************************************************************************
                       FUNCTION DECLARATIONS
**************************************************************************/
void Delay_us(int us);
void Data(int Value);           
void Cmd(int Value);            
void Send2Lcd(const char Adr, const char *Lcd);

/*************************************************************************
                           MAIN FUNCTION
**************************************************************************/
void main()                     
{
 TRISC=0X00;                  /* PORTC(control lines) configured as o/p  */
 TRISD=0X00;                  /* PORTD(data lines) configured as o/p     */
 Delay_us(25);              
 Cmd(0X30);                   /* LCD Specification Commands              */
 Delay_us(25);     
 Cmd(0X30);                   /* LCD Specification Commands              */
 Delay_us(25);      
 Cmd(0X30);                   /* LCD Specification Commands              */
 Delay_us(25);   
 Cmd(0X38);                   /* Double Line Display Command             */
 Cmd(0X06);                   /* Auto Increment Location Address Command */
 Cmd(0X0C);                   /* Display ON Command                      */
 Cmd(0X01);                   /* Clear Display Command                   */
 Delay_us(1000);              
 Send2Lcd(0x84,"rhydoLABZ");  /* Displays string in the first line       */
 Send2LCD(0xc5,"Cochin");     /* Displays string in the second line      */
 while(1);
}

/*************************************************************************
* Function    : Cmd                                                      *
*                                                                        *
* Description : Function to send a command to LCD                        *
*                                                                        *
* Parameters  : Value - command to be sent                               *
**************************************************************************/
void Cmd(int Value)
{
 PORTD = Value;               /* Write the command to data lines         */
 RC0   = 0;                   /* RS-0(command register)                  */
 RC1   = 1;                   /* E-1(enable)                             */
 Delay_us(25);                
 RC1   = 0;                   /* E-0(enable)                             */
}

/*************************************************************************
* Function    : Data                                                     *
*                                                                        *
* Description : Function to display single character on LCD              *
*                                                                        *
* Parameters  : Value - character to be displayed                        *
**************************************************************************/
void Data(int Value)
{
 PORTD = Value;               /* Write the character to data lines       */
 RC0   = 1;                   /* RS-1(data register)                     */
 RC1   = 1;                   /* E-1(enable)                             */
 Delay_us(25);                
 RC1   = 0;                   /* E-0(enable)                             */
}

/*************************************************************************
* Function    : Send2LCD                                                 *
*                                                                        *
* Description : Function to display string on LCD                        *
*                                                                        *
* Parameters  : Adr - location                                           *
*               String to be displayed                                   *
**************************************************************************/
void Send2Lcd(const char Adr, const char *Lcd)
{
 Cmd(Adr);                    /* Address of location to display string   */
 while(*Lcd!='\0')            /* Check for termination character         */
 {	
  Data(*Lcd);                 /* Display the character on LCD            */	
  Lcd++;                      /* Increment the pointer                   */
 }
}

/*************************************************************************
* Function    : Delay_us                                                 *
*                                                                        *
* Description : Function for 1 microsecond delay                         *
*                                                                        *
* Parameter   : us - delay in microseconds                               *
**************************************************************************/
void Delay_us(int us)
{
 us=us>>1;
 while(us!=1)
 us--;
}

/***************************  END OF PROGRAM  ****************************/

100

101

102

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

HEADER FILES

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

#include<pic18.h>

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

FUNCTION DECLARATIONS

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

void Delay_us(int us);

void Data(int Value);

void Cmd(int Value);

void Send2Lcd(const char Adr, const char *Lcd);

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

MAIN FUNCTION

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

void main()

{

TRISC=0X00; /* PORTC(control lines) configured as o/p */

TRISD=0X00; /* PORTD(data lines) configured as o/p */

Delay_us(25);

Cmd(0X30); /* LCD Specification Commands */

Delay_us(25);

Cmd(0X30); /* LCD Specification Commands */

Delay_us(25);

Cmd(0X30); /* LCD Specification Commands */

Delay_us(25);

Cmd(0X38); /* Double Line Display Command */

Cmd(0X06); /* Auto Increment Location Address Command */

Cmd(0X0C); /* Display ON Command */

Cmd(0X01); /* Clear Display Command */

Delay_us(1000);

Send2Lcd(0x84,"rhydoLABZ"); /* Displays string in the first line */

Send2LCD(0xc5,"Cochin"); /* Displays string in the second line */

while(1);

}

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

* Function : Cmd *

* *

* Description : Function to send a command to LCD *

* *

* Parameters : Value - command to be sent *

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

void Cmd(int Value)

{

PORTD = Value; /* Write the command to data lines */

RC0 = 0; /* RS-0(command register) */

RC1 = 1; /* E-1(enable) */

Delay_us(25);

RC1 = 0; /* E-0(enable) */

}

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

* Function : Data *

* *

* Description : Function to display single character on LCD *

* *

* Parameters : Value - character to be displayed *

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

void Data(int Value)

{

PORTD = Value; /* Write the character to data lines */

RC0 = 1; /* RS-1(data register) */

RC1 = 1; /* E-1(enable) */

Delay_us(25);

RC1 = 0; /* E-0(enable) */

}

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

* Function : Send2LCD *

* *

* Description : Function to display string on LCD *

* *

* Parameters : Adr - location *

* String to be displayed *

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

void Send2Lcd(const char Adr, const char *Lcd)

{

Cmd(Adr); /* Address of location to display string */

while(*Lcd!='\0') /* Check for termination character */

{

Data(*Lcd); /* Display the character on LCD */

Lcd++; /* Increment the pointer */

}

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

* Function : Delay_us *

* *

* Description : Function for 1 microsecond delay *

* *

* Parameter : us - delay in microseconds *

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

void Delay_us(int us)

{

us=us>>1;

while(us!=1)

us--;

}

/*************************** END OF PROGRAM ****************************/

Topics related to PIC18F4520 Mini Development Board

Resources

Softwares

Datasheets
- PIC18F4520
- MCP9700
- MAX232
- CP2102
- LM7805
- LD1117
- LCD (16×2)

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