AVR UART

aarduinoserialreceiver.ino

void setup(){
  Serial.begin(9600);
  Serial1.begin(9600);
  Serial.println("Init");
  pinMode(13, OUTPUT);
}

char b;

void loop(){
  if ((b = Serial1.read()) > 0){
    Serial.println(b);
    digitalWrite(13, HIGH);
  } else {
    digitalWrite(13, LOW);
  }
}

atmega8uart.c

#define F_CPU 8000000UL
#define BAUD 9600
#define MYUBRR F_CPU/16/BAUD - 1
#include <avr/io.h>
#include <util/delay.h>

void USART_Init(unsigned int ubrr)
{
	UBRRH = (unsigned char) (ubrr >> 8);
	UBRRL = (unsigned char) ubrr;
	
	UCSRB = (1 << RXEN) | (1 << TXEN);
	UCSRC = (1 << URSEL) | (1 << USBS) | (3 <<UCSZ0);
	
}

void USART_Transmit(unsigned char data){
	while (!(UCSRA & (1 << UDRE))) {};
	UDR = data;
}


int main(void){
	USART_Init(MYUBRR);
	while(1){
		
		USART_Transmit('b');
		_delay_ms(1000);
	}
}

successfulsend.c

/*
 * GccApplication5.c
 *
 * Created: 10/5/2016 1:26:23 PM
 * Author : Manash
 */ 

#define F_CPU 16000000UL
#define BAUD 9600
#define MYUBRR F_CPU/16/BAUD - 1
#include <avr/io.h>
#include <util/delay.h>

void USART_Init(unsigned int ubrr)
{
	UBRRH = (unsigned char) (ubrr >> 8);
	UBRRL = (unsigned char) ubrr;
	
	UCSRB = (1 << RXEN) | (1 << TXEN);
	UCSRC = (1 << URSEL) | (1 << USBS) | (3 <<UCSZ0);
	
}



void USART_Transmit(unsigned char data){
	while (!(UCSRA & (1 << UDRE)));
	UDR = data;
}


void USART_putstring(char* StringPtr){
	
	while(*StringPtr != 0x00){    //Here we check if there is still more chars to send, this is done checking the actual char and see if it is different from the null char
		USART_Transmit(*StringPtr);    //Using the simple send function we send one char at a time
	StringPtr++;
	}        //We increment the pointer so we can read the next char
}

int main(void)
{
	USART_Init(MYUBRR);
	char strng[] = {'a', 'b', 'c', '\n', '\0'};
    /* Replace with your application code */
    while (1) 
    {
		while (( UCSRA & (1<<UDRE))  == 0){};
		int i;
		for (i = 0; i < strlen(strng); i++){
			while (( UCSRA & (1<<UDRE))  == 0){};
			UDR = strng[i];
			if (i == (strlen(strng) - 1)){
				_delay_ms(1000);
			}
		}
	}
    
}