(ESL9) LCD & Keypad Interfacing

Code

#include <LPC17xx.h>
#include "lcd.h"

void scan(void);

unsigned char Msg1[14] = "ALS BENGALURU";
unsigned char Msg2[13] = "KEY PRESSED=";
unsigned char col, row, var, flag, key, *ptr;
unsigned long int i, var1, temp, temp3;

unsigned char SCAN_CODE[16] = {
	0x1E, 0x1D, 0x1B,	0x17,
	0x2E,	0x2D, 0x2B,	0x27,
	0x4E,	0x4D,	0x4B,	0x47,
	0x8E, 0x8D,	0x8B,	0x87,
};

unsigned char ASCII_CODE[16] = {
	'0', '1',	'2', '3',
	'4', '5',	'6', '7',
	'8', '9', 'A', 'B',
	'C', 'D', 'E', 'F',
};

int main(void)
{
	LPC_PINCON->PINSEL3 = 0x00000000; // P1.20 to P1.23 MADE GPIO
	LPC_PINCON->PINSEL0 = 0x00000000; // P0.15 as GPIO
	LPC_PINCON->PINSEL1 = 0x00000000; // P0.16 t0 P0.18 made GPIO
	LPC_GPIO0->FIODIR &= ~0x00078000; // made INput P0.15 to P0.18 (cols)
	LPC_GPIO1->FIODIR |= 0x00F00000;  // made output P1.20 to P1.23 (rows)
	LPC_GPIO1->FIOSET = 0x00F00000;

	lcd_init();

	temp1 = 0x80; // point to first line of LCD
	lcd_com();
	delay_lcd(800);
	lcd_puts(&Msg1[0]); // display the messsage

	temp1 = 0xC0; // point to first line of LCD
	lcd_com();
	delay_lcd(800);
	lcd_puts(&Msg2[0]); // display the messsage

	while (1)
	{
		while (1)
		{
			for (row = 1; row < 5; row++)
			{
				if (row == 1)
					var1 = 0x00100000;
				else if (row == 2)
					var1 = 0x00200000;
				else if (row == 3)
					var1 = 0x00400000;
				else if (row == 4)
					var1 = 0x00800000;

				temp = var1;

				LPC_GPIO1->FIOSET = 0x00F00000;
				LPC_GPIO1->FIOCLR = var1;

				flag = 0;
				scan();
				if (flag == 1)
					break;

			} // end for(row=1;row<5;row++)

			if (flag == 1)
				break;

		} // 2nd while(1)

		for (i = 0; i < 16; i++)
		{
			if (key == SCAN_CODE[i])
			{
				key = ASCII_CODE[i];
				break;
			} // end if(key == SCAN_CODE[i])

		} // end for(i=0;i<16;i++)

		temp1 = 0xCC;
		lcd_com();
		delay_lcd(800);
		lcd_puts(&key);

	} // end while 1
} // end main

void scan(void)
{
	unsigned long temp3;
	temp3 = LPC_GPIO0->FIOPIN;
	temp3 &= 0x00078000;
	if (temp3 != 0x00078000)
	{
		for (i = 0; i < 500; i++)
			;
		temp3 = LPC_GPIO0->FIOPIN;
		temp3 &= 0x00078000;
		if (temp3 != 0x00078000)
		{
			flag = 1;
			temp3 >>= 15; // Shifted to come at LN of byte
			temp >>= 16;  // shifted to come at HN of byte
			key = temp3 | temp;
		} // 2nd if(temp3 != 0x00000000)
	} // 1st if(temp3 != 0x00000000)
} // end scan