This example describes how to display a string in LCD using 4 bit mode

Procedure for LCD Interface with Cortex M4

1. Power: In the PCONP register, set the PCGPIO bit
2. Configure all the LCD pins as GPIO using IOCON registers
3. Configure all the LCD pins as outputs
4. Initialize LCD by sending initialization commands
   Command software routine:
5. Make RS pin low
6. Place the MSB 4bits of command on data lines and Pulse the ENABLE pin
7. Place the LSB 4bits of command on data lines and Pulse the ENABLE pin
   Data software routine:
8. Make RS pin high
9. Place the MSB 4bits of data on data lines and Pulse the ENABLE pin
10. Place the LSB 4bits of data on data lines and Pulse the ENABLE pin
11. Send First line command using command software routine
12. Send 16 characters of data using data software routine
13. Send Second line command using command software routine
14. Send 16 characters of data using data software routine

#include "LPC407x_8x_177x_8x.h"

#define RS_PORT		(0)
#define RS_PIN		(4)
#define RS_VAL		(1 << RS_PIN)

#define EN_PORT		(0)
#define EN_PIN		(5)
#define EN_VAL		(1 << EN_PIN)

#define DATA      LPC_GPIO4->PIN

//data array
unsigned char Lcd_LINE1[]={"CORTEX DEV BOARD"},i=0;
unsigned char Lcd_LINE2[]={"LCD DEMO PROGRAM"};
	
void delay_ms(long ms);
void lcd_command(unsigned char cmd);
void lcd_data(unsigned char data);
void lcd_init(void);

int main(void)
{
		
		//1. Set the PCGPIO bit
		LPC_SC->PCONP |= (1<<15);
	
		//2. Configure all the LCD pins as GPIO
		//	 RS-P0.4, EN-P0.5, Datalines-P4.28 to P4.31
		LPC_IOCON->P0_4 = 0;
		LPC_IOCON->P0_5 = 0;
		LPC_IOCON->P4_28 = 0;
		LPC_IOCON->P4_29 = 0;
		LPC_IOCON->P4_30 = 0;
		LPC_IOCON->P4_31 = 0;

	
		//3. Configure the pins P4.28 to P4.31 as output
		//	 Configure the pins P0.4 and P0.5 as output
		LPC_GPIO0->DIR |= 0x30;
		LPC_GPIO4->DIR  = (0xF << 28);
	
		//4. Initialize LCD by sending Initialisation commands
		lcd_init();
	
		while (1)
		{
				//11. Send First line command
				lcd_command(0x80);
				//12. Send 16 characters from the line1 array
				for(i=0;Lcd_LINE1[i]!='\0';i++)
				{
					lcd_data(Lcd_LINE1[i]);
					delay_ms(50);
				}
				
				//13. Send Second line command
				lcd_command(0xc0);
				//14. Send 16 characters from the line2 array
				for(i=0;Lcd_LINE2[i]!='\0';i++)
				{
					lcd_data(Lcd_LINE2[i]);
					delay_ms(50);
				}	
				delay_ms(1000);
				//Clear the display and repeat
				lcd_command(0x01);
		}
}

void lcd_command(unsigned char cmd)
{
		//5. Clear RS pin--Command mode
		LPC_GPIO0->CLR |= RS_VAL;

		//6. Place the MSB 4bits on data lines
		DATA=cmd<<24;
	  //6. Pulse the EN pin
		LPC_GPIO0->PIN |= EN_VAL;
		LPC_GPIO0->CLR |= EN_VAL;

		//7. Place the LSB 4bits on data lines
		DATA=cmd<<28;
		//7. Pulse the EN pin
		LPC_GPIO0->PIN |= EN_VAL;
		LPC_GPIO0->CLR |= EN_VAL;
		delay_ms(5);
}

void lcd_data(unsigned char data)		
{
		//8. Set RS pin--data mode
		LPC_GPIO0->PIN |= RS_VAL;

		//9. Place the MSB 4bits on data lines
		DATA=data<<24;
		//9. Pulse the EN pin
		LPC_GPIO0->PIN |= EN_VAL;
		LPC_GPIO0->CLR |= EN_VAL;
	
		//10. Place the LSB 4bits on data lines
		DATA=data<<28;
		//10. Pulse the EN pin
		LPC_GPIO0->PIN |= EN_VAL;
		LPC_GPIO0->CLR |= EN_VAL;
		delay_ms(5);			
}

void lcd_init(void)
{
		delay_ms(100);   					//LCD powerup time
		lcd_command(0x33);				//Wake up
		lcd_command(0x32);				//Wake up
		lcd_command(0x28);				//4bit mode
		lcd_command(0x0C);				//display on and cursor off
		lcd_command(0x06);				//Entry mode and shift
		lcd_command(0x01);				//Clear LCD
		delay_ms(200);						//Give more time to settle
}

void delay_ms(long ms) 					// delay 1 ms per count @ CCLK 120 MHz
{
		long i,j;
		for (i = 0; i < ms; i++ )
		for (j = 0; j < 26659; j++ );
}