PIC16F877A – Interfacing LCD

PIC16F877A Mini Development Board comes with an LCD module (2×16) operating at 5V. Control lines (RS, R/W, E) are connected to port pins RC0(RS), RC1(E) and data lines (D0-D7) to port pins RD0-RD7 whereas R/W is directly grounded. The board has a potentiometer to adjust LCD contrast. For reliable performance, LCD has to be initialized with certain commands.

Note: By default, LCD works in 8-bit mode (jumpers J11-J14 are shorted, connecting D0-D7 to port pins RD0-RD7). If these jumpers are left open, then LCD can be operated in 4-bit mode with data lines D4-D7.

Schematic

Sample Code (8-bit)

The sample code below gives LCD display output ” RhydoLABZ ” in line 1 and “Cochin” in line 2 .

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

/*************************************************************************
                       FUNCTION DECLARATIONS
**************************************************************************/
void LCD_Command(int com);
void LCD_Data(int data);                       
void Send2LCD(const char loc, const char *LCD);
void Delay_us(char Delay);
void Delay_100us(unsigned long int Delay);

/*************************************************************************
                           MAIN FUNCTION
**************************************************************************/
void main()                    
{
 TRISC = 0X00;                /* PORTC(control lines) configured as o/p  */
 TRISD = 0X00;                /* PORTD(data lines) configured as o/p     */
 LCD_Command(0X30);           /* LCD specification command               */    
 Delay_us(35);    
 LCD_Command(0X30);           /* LCD specification command               */
 Delay_us(35);       
 LCD_Command(0X30);           /* LCD specification command               */
 Delay_us(35);   
 LCD_Command(0X38);           /* Double Line Display Command             */
 LCD_Command(0X06);           /* Auto Increment Location Address Command */
 LCD_Command(0X0C);           /* Display ON Command                      */
 LCD_Command(0X01);           /* Clear Display Command                   */
 Delay_100us(30);
 Send2LCD(0x84,"RhydoLABZ");  /* Displays string in the first line       */
 Send2LCD(0xc5,"Cochin");     /* Displays string in the second line      */

 while(1);
}

/*************************************************************************
* Function    : LCD_Command                                              *
*                                                                        *
* Description : Function to send a command to LCD                        *
*                                                                        *
* Parameters  : com - command to be sent                                 *
**************************************************************************/
void LCD_Command(int com)
{
 RC0   = 0;                   /* RS-0(Command register)                  */
 RC1   = 1;                   /* E-1(Enable pin high)                    */
 PORTD = com;                 /* Write the command to data lines         */ 
 Delay_us(30);
 RC1   = 0;                   /* E-0(Enable pin low)                     */
}    

/*************************************************************************
* Function    : LCD_Data                                                 *
*                                                                        *
* Description : Function to display single character on LCD              *
*                                                                        *
* Parameters  : data - character to be displayed                         *
**************************************************************************/
void LCD_Data(int data)
{
 RC0   = 1;                   /* RS-1(Data register)                     */
 RC1   = 1;                   /* E-1(Enable pin high)                    */
 PORTD = data;                /* Write the character to data lines       */       
 Delay_us(30);        
 RC1   = 0;                   /* E-0(Enable pin low)                     */
}

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

/*************************************************************************
* Function    : Delay_us                                                 *
*                                                                        *
* Description : Function for 1 microsecond delay                         *
*                                                                        *
* Parameter   : Delay - delay in microseconds                            *
**************************************************************************/
void Delay_us(char Delay)    
{        
 while((--Delay)!=0);    
}

/*************************************************************************
* Function    : Delay_100us                                              *
*                                                                        *
* Description : Function for delay                                       *
*                                                                        *
* Parameter   : Delay - delay                                            *
**************************************************************************/
void Delay_100us(unsigned long int Delay)
{
 Delay = Delay*15;
 while((--Delay)!=0);
}

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

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

HEADER FILES

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

#include<pic.h>

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

FUNCTION DECLARATIONS

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

void LCD_Command(int com);

void LCD_Data(int data);

void Send2LCD(const char loc, const char *LCD);

void Delay_us(char Delay);

void Delay_100us(unsigned long int Delay);

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

MAIN FUNCTION

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

void main()

{

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

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

LCD_Command(0X30); /* LCD specification command */

Delay_us(35);

LCD_Command(0X30); /* LCD specification command */

Delay_us(35);

LCD_Command(0X30); /* LCD specification command */

Delay_us(35);

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

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

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

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

Delay_100us(30);

Send2LCD(0x84,"RhydoLABZ"); /* Displays string in the first line */

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

while(1);

}

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

* Function : LCD_Command *

* *

* Description : Function to send a command to LCD *

* *

* Parameters : com - command to be sent *

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

void LCD_Command(int com)

{

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

RC1 = 1; /* E-1(Enable pin high) */

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

Delay_us(30);

RC1 = 0; /* E-0(Enable pin low) */

}

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

* Function : LCD_Data *

* *

* Description : Function to display single character on LCD *

* *

* Parameters : data - character to be displayed *

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

void LCD_Data(int data)

{

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

RC1 = 1; /* E-1(Enable pin high) */

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

Delay_us(30);

RC1 = 0; /* E-0(Enable pin low) */

}

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

* Function : Send2LCD *

* *

* Description : Function to display string on LCD *

* *

* Parameters : loc - location *

* String to be displayed *

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

void Send2LCD(const char loc, const char *LCD)

{

LCD_Command(loc); /* Address of location to display string */

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

{

LCD_Data(*LCD); /* Display the character on LCD */

LCD++; /* Increment the pointer */

}

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

* Function : Delay_us *

* *

* Description : Function for 1 microsecond delay *

* *

* Parameter : Delay - delay in microseconds *

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

void Delay_us(char Delay)

{

while((--Delay)!=0);

}

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

* Function : Delay_100us *

* *

* Description : Function for delay *

* *

* Parameter : Delay - delay *

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

void Delay_100us(unsigned long int Delay)

{

Delay = Delay*15;

while((--Delay)!=0);

}

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

Topics related to PIC16F877A Development Board-Mini

Resources

Softwares

Datasheets
- PIC 16F877A
- MCP9700
- MAX232
- CP2102
- LM7805
- LD1117
- LCD (16×2)

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