/*  Name     : Main.c
 *  Purpose  : Source code for keypad Interfacing with ATMEGA16.
 *  Author   : GEMICATES
 *  Date     : 04-07-2017
 *  Website  : www.gemicates.org
 *  Revision : None
 */

#include<avr/io.h>				// Header File for ATMEGA16
#include<util/delay.h>			        // Include Delay Function

	#define KEY PORTB		        // To Set Port B as Keypad

	#define r1 PB0			        // To Set Pin B0-B3 as Keypad Row			
	#define r2 PB1
	#define r3 PB2
	#define r4 PB3
 
	#define c1 PB4   		        // To Set Pin B4-B6 as Keypad Column	
	#define c2 PB5
	#define c3 PB6

/* Function to Check Four Rows and Columns*/
void check1(void);
void check2(void);  
void check3(void);
void check4(void);
 
	#define LCD_DATA PORTD		        // To Set Port D as LCD data Pins
 
	#define CON PORTA			// To Set Port A Pins A0-A2 as LCD Control Pins 

	#define en PA2				// Enable signal
	#define rw PA1				// Read/Write signal
	#define rs PA0				// Resister Select signal
 
/* Function For LCD display*/
void LCD_cmd(unsigned char cmd);
void init_LCD(void);
void LCD_write(unsigned char data);
void string(unsigned char *str);
 
/* Main Function*/

void main()
{
	unsigned char value; 
 
	DDRD=0xff;			        // LCD_DATA port as output port
	DDRA=0x07;			        // Set the Data Direction Register (A2-A0) as Ouput
	DDRB=0x0F;			        // Set the Data Direction Register (B3-B0) as Ouput
	KEY=0xf0;			        // Make Input Pins are High
	init_LCD();			        // initialization of LCD
    LCD_cmd(0x86);  	                        // bring cursor to position 6 of ROW 1	
	LCD_write('H');
	LCD_cmd(0x87);  	                // bring cursor to position 7 of ROW 1													
	LCD_write('I');
	LCD_write('!');
	_delay_ms(50);
	LCD_cmd(0xC3);		                // bring cursor to position 3 of ROW 2
	string("**GUYS**");
	_delay_ms(50);
	LCD_cmd(0x01);  		        // clear screen
				
	LCD_cmd(0x83);			        // bring cursor to position 3 of ROW 1
	string("WELCOME TO");
	_delay_ms(100);
	LCD_cmd(0xC3);			        // bring cursor to position 3 of ROW 2
	string("GEMICATES");
	_delay_ms(100);
	LCD_cmd(0x01);		 	        // clear screen
	LCD_cmd(0x0C);  	                // Display On cursor Off
	string("press a key");
	LCD_cmd(0xc0);
 
 
	while(1)
	{
		PORTB=0xF0;			// Set all the input to one
		value=PINB;			// Get the PORTD value in variable "value"
		if(value!=0xf0)		        // If any key is pressed value changed
		{
			check1();
			check2();
			check3();
			check4();
		}
	}
	return 0;
}
 
void check1(void)			        // To check Row1
{
	KEY =0b11111110;
	_delay_ms(20);
	if(bit_is_clear(PINB,c1))
	{
	output(1);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c2))
	{
	output(2);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c3))
	{
	output(3);
	_delay_ms(20);
	}
}

 
 
void check2(void)			        // TO check Row2
{
	KEY=0b11111101;
	_delay_ms(20);
	if(bit_is_clear(PINB,c1))
	{
	output(4);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c2))
	{
	output(5);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c3))
	{
	output(6);
	_delay_ms(20);
	}
}
 
void check3(void)				// To check Row3
{
	KEY=0b11111011;
	_delay_ms(20);
	if(bit_is_clear(PINB,c1))
	{
	output(7);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c2))
	{
	output(8);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c3))
	{
	output(9);
	_delay_ms(20);
	}
 }
void check4(void)				// To check Row4
{
	KEY =0b11110111;
	_delay_ms(20);
	if(bit_is_clear(PINB,c1))
	{
	output(10);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c2))
	{
	output(11);
	_delay_ms(20);
	}
	else if(bit_is_clear(PINB,c3))
	{
	output(12);
	_delay_ms(20);
	}
} 
void init_LCD(void)
{
 
	LCD_cmd(0x38);		                // initializtion of 16X2 LCD in 8bit mode
	_delay_ms(1);
 
	LCD_cmd(0x01);		                // clear LCD
	_delay_ms(1);
 
	LCD_cmd(0x0E);		                // cursor ON
	_delay_ms(1);
 
	LCD_cmd(0x80);		                // ---8 go to first line and --0 is for 0th position
	_delay_ms(1);
	return;
}
 
void LCD_cmd(unsigned char cmd)
{
	LCD_DATA=cmd;
	CON =(0<<rs)|(0<<rw)|(1<<en);	        // making RS and RW as LOW and EN as HIGH
	_delay_ms(1);
	CON =(0<<rs)|(0<<rw)|(0<<en);         	// making RS, RW , LOW and EN as LOW
	_delay_ms(50);
	return;
}
 
 
void LCD_write(unsigned char data)
{
	LCD_DATA= data;
	CON = (1<<rs)|(0<<rw)|(1<<en);	        // making RW as LOW and RS, EN as HIGH
	_delay_ms(1);
	CON = (1<<rs)|(0<<rw)|(0<<en);	        // making EN and RW as LOW and RS HIGH
	_delay_ms(50);				// give a 10 milli second delay to get thigs executed
	return ;
}
 
void string(unsigned char *str)	                // take address vaue of the string in pionter *str
{
	int i=0;
	while(str[i]!='\0')			// loop will go on till the NULL charaters is soon in string 
	{
		LCD_write(str[i]);		// sending data on CD byte by byte
		i++;
	}
	return;
}

void output(int rev)
{
	LCD_cmd(0x01);				// clear screen
	LCD_cmd(0x86);				// bring cursor to position 3 of ROW 1
	switch(rev)
	{
		case 1:
			string("ONE");
			_delay_ms(1000);
		break;
		
		case 2:
			string("TWO");
			_delay_ms(1000);
		break;
		
		case 3:
			string("THREE");
			_delay_ms(1000);
		break;
		
		case 4:
			string("FOUR");
			_delay_ms(1000);
		break;
		
		case 5:
			string("FIVE");
			_delay_ms(1000);
		break;
		
		case 6:
			string("SIX");
			_delay_ms(1000);
		break;
		
		case 7:
			string("SEVEN");
			_delay_ms(1000);
		break;
		
		case 8:
			string("EIGHT");
			_delay_ms(1000);
		break;
		
		case 9:
			string("NINE");
			_delay_ms(1000);
		break;
		
		case 10:
			string("TEN");
			_delay_ms(1000);
		break;
		
		case 11:
			string("ELEVEN");
			_delay_ms(1000);

		break;
		
		case 12:
			string("TWELVE");
			_delay_ms(1000);
		break;
	}
}