/*  Name     : main.c
 *  Purpose  : Source code for RFID interface with ATMEGA16.
 *  Author   : Gemicates
 *  Date     : 2017-09-11
 *  Website  : www.gemicates.org
 *  Revision : None
 */
                                              // Program to get the 12 byte string and display it on LCD by Polling method:
/*
The RFID unique code is been displayed on LCE
LCD DATA port----PORT B
ctrl port------PORT D
	rs-------PD0
	rw-------PD1
	en-------PD2
*/

#define F_CPU 8000000UL

#define USART_BAUDRATE 9600
#define BAUD_PRESCALE (((F_CPU / (USART_BAUDRATE * 16UL))) - 1)

#include<avr/io.h>
#include<util/delay.h>
#define delay_ms;
#define LCD_DATA PORTA	                      // LCD data port
#define ctrl PORTB
#define en PB2		                      // enable signal
#define rw PB1		                      // read/write signal
#define rs PB0		       	              // register select signal

void LCD_cmd(unsigned char cmd);
void init_LCD(void);
void LCD_write(unsigned char data);

void usart_init();
unsigned int usart_getch();

unsigned char i, card[12];
void getcard_id(void);
void LCD_display(void);

int main(void)
{
	DDRA=0xff;		              // LCD_DATA port as output port
	DDRB=0x07;		              // ctrl as output
	init_LCD();		              // initialization of LCD
	delay_ms(50);		              // delay of 50 milliseconds
	usart_init();		              // initiailztion of USART
	LCD_write_string("Unique ID No.");    // Function to display string on LCD
	
	while(1)
	{
		getcard_id();	              // Function to get RFID card no. from serial port
		LCD_cmd(0xC0);	              // to go in second line and zeroth position on LCD
		LCD_display();		      // a function to write RFID card no. on LCD
	}
	return 0;
}

void getcard_id(void)	                      // Function to get 12 byte ID no. from rfid card
{	
	for(i=0;i<12;i++) 
	{
		card[i]= usart_getch();	      // receive card value byte by byte
	}
	return;
}

void LCD_display(void)	                      // Function for displaying ID no. on LCD
{
	for(i=0;i<12;i++)
	{
		LCD_write(card[i]);	      // display card value byte by byte
	}
	return;
}

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;
	ctrl =(0<<rs)|(0<<rw)|(1<<en);	
	_delay_ms(1);
	ctrl =(0<<rs)|(0<<rw)|(0<<en);	
	_delay_ms(50);
	return;
}

void LCD_write(unsigned char data)
{
	LCD_DATA= data;
	ctrl = (1<<rs)|(0<<rw)|(1<<en);
	_delay_ms(1);
	ctrl = (1<<rs)|(0<<rw)|(0<<en);
	_delay_ms(50);			
	return ;
}

void usart_init()
{
	UCSRB |= (1 << RXEN) | (1 << TXEN);   // Turn on the transmission and reception circuitry
	UCSRC |= (1 << URSEL) | (1<<USBS) | (1 << UCSZ0) | (1 << UCSZ1); 
				              // Use 8-bit character sizes

	UBRRL = 0x51; 	                      // Load lower 8-bits of the baud rate value..
					      // into the low byte of the UBRR register
	UBRRH = 0x103;                        // Load upper 8-bits of the baud rate value..
                                              // into the high byte of the UBRR register
}

unsigned int usart_getch()
{
	while ((UCSRA & (1 << RXC)) == 0);   // Do nothing until data have been received..
					     // and is ready to be read from UDR
	return(UDR);                         // return the byte
}

void LCD_write_string(unsigned char *str)    // take address value of the string in pointer *str
{
	int i=0;
	while(str[i]!='\0')		     // loop will go on till the NULL characters is soon in string 
 	{
		LCD_write(str[i]);	     // sending data on LCD byte by byte
		i++;
	}
	return;
}