- ARM

LCD Interfacing ARM LPC2148 Embedded C

LCD Interfacing-ARM LPC2148 
Introduction:



This Code is specially developed for LCD on ALS ARM LPC2148 Evaluation Board.
A 16*2 Alphanumeric display with backlight is provided on Evaluation Board.
  • Mode of Operation:- LCD is interfaced using 4 bit Mode.
  • Port Details:   P0.2 to P0.7  are used for LCD interfacing.
RS = 0 for sending Command to the LCD, controlled by port P0.2
RS = 1 for sending Data to the LCD, controlled by port P0.2
EN = 0 for disabling the LCD ,controlled by port P0.3
EN = 1 for enabling the LCD, controlled by port P0.3
D4 to D7 (P0.4 to P0.7) – data lines

Program:


// LCD INTERFACING USING LPC2148
//----------------------------------------------------------------
// CONTROLLER : LPC-2148
// Developed By : Abhay Kagalkar
//----------------------------------------------------------------
#include <lpc214x.h >
#include<stdio.h>

//Function prototypes
void delay(unsigned int);
void comm(void);
void writeData(void);
void data(void);
void lcd_initialize(void);
void writeCommand(void);
void clr_display(void);


unsigned char temp1;
unsigned long int temp,r=0;
unsigned char *ptr;
unsigned char data1[] = "CODESEXPLORER",data2[] = "ABHAY KAGALKAR";

int main()
{
IO0DIR = 0x000000FC; //configure o/p lines for lcd
lcd_initialize(); //lcd intialisation
delay(3200);
clr_display(); //clear display
delay(3200);
temp1 = 0x80; //Display starting address of first line
comm();
ptr = data1;
while(*ptr!='')
{
temp1 = *ptr;
data();
ptr ++;
}
temp1 = 0xC0; // Display starting address of second line 1st pos
comm();
ptr = data2;
while(*ptr!='')
{
temp1 = *ptr;
data();
ptr ++;
}
while(1);

} //end of main()
void delay(unsigned int r1)
{
for(r=0;r<r1;r++);
}
// lcd initialisation routine.
void lcd_initialize(void)
{
temp = 0x30;
writeCommand();
delay(3200);

temp = 0x30;
writeCommand();
delay(3200);

temp = 0x30;
writeCommand();
delay(3200);

temp = 0x20; // change to 4 bit mode from default 8 bit mode
writeCommand();
delay(3200);

temp = 0x28; // load command for lcd function setting with lcd in 4 bit mode,
comm(); // 2 line and 5x7 matrix display
delay(3200);

comm();
temp1 = 0x0C; // load a command for display on, cursor on and blinking off
delay(800);

temp1 = 0x06; // command for cursor increment after data dump
comm();
delay(800);

temp1 = 0x80; // set the cursor to beginning of line 1
comm();
delay(800);
}

void comm(void)
{
temp = temp1 & 0xf0;
writeCommand();
temp = temp1 & 0x0f;
temp = temp << 4;
writeCommand();
delay(500);
}

// command nibble o/p routine
void writeCommand(void) //write the values to command reg
{
IO0CLR = 0x000000FC; // clear the port lines.
IO0SET = temp; // Assign the value to the PORT lines
IO0CLR = 0x00000004; // clear bit RS = 0
IO0SET = 0x00000008; // E=1
delay(10);
IO0CLR = 0x00000008;
}
// data nibble
void writeData(void) ////write the values to data reg
{
IO0CLR = 0x000000FC; // clear the port lines.
IO0SET = temp; // Assign the value to the PORT lines
IO0SET = 0x00000004; // set bit RS = 1
IO0SET = 0x00000008; // E=1
delay(10);
IO0CLR = 0x00000008;
}
// data o/p routine which also outputs high nibble first
// and lower nibble next
void data(void)
{
temp = temp1 & 0xf0;
temp = temp ;//<< 6;
writeData();
temp= temp1 & 0x0f;
temp= temp << 4;
writeData();
delay(100);
}
void clr_display(void)
{
temp1 = 0x01;
comm();
delay(500);
}


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