AVR USART maxEmbedded.com

#include <avr/io.h>
#include <util/delay.h>
#include <stdlib.h>
#include "lcd.h"                            // include LCD library

#define BAUD 9600                           // define baud
#define BAUDRATE ((F_CPU)/(BAUD*16UL)-1)    // set baudrate value for UBRR

#ifndef F_CPU
#define F_CPU 16000000UL                    // set the CPU clock
#endif

// function to initialize UART
void uart_init (void)
{
    UBRRH=(BAUDRATE>>8);
    UBRRL=BAUDRATE;                         //set baud rate
    UCSRB|=(1<<TXEN)|(1<<RXEN);             //enable receiver and transmitter
    UCSRC|=(1<<URSEL)|(1<<UCSZ0)|(1<<UCSZ1);// 8bit data format
}

// function to send data - NOT REQUIRED FOR THIS PROGRAM IMPLEMENTATION
void uart_transmit (unsigned char data)
{
    while (!( UCSRA & (1<<UDRE)));          // wait while register is free
    UDR = data;                             // load data in the register
}

// function to receive data
unsigned char uart_recieve (void)
{
    while(!(UCSRA) & (1<<RXC));             // wait while data is being received
    return UDR;                             // return 8-bit data
}

// main function: entry point of program
int main (void)
{
    unsigned char a;
    char buffer[10];

    uart_init();                            // initialize UART
    lcd_init(LCD_DISP_ON_CURSOR);           // initialize LCD
    lcd_home();                             // goto LCD Home

    while(1)
    {
        a=uart_recieve();                   // save the received data in a variable
        itoa(a,buffer,10);                  // convert numerals into string
        lcd_clrscr();                       // LCD clear screen
        lcd_home();                         // goto LCD home
        lcd_puts(buffer);                   // display the received value on LCD
        _delay_ms(100);                     // wait before next attempt
    }

    return 0;
}