/*

  Test for UART TX buffer
  
*/

#include <avr/io.h>

#define TEST1_HIGH PORTD |=  (1<<PD2);
#define TEST1_LOW  PORTD &= ~(1<<PD2);

#define F_CPU 16000000
#include <util/delay.h>

#define BAUD 9600L
// don't change below, will be calculated

#define UBRR_VAL  ((F_CPU+BAUD*8)/(BAUD*16)-1)  
#define BAUD_REAL (F_CPU/(16*(UBRR_VAL+1)))     
#define BAUD_ERROR ((BAUD_REAL*1000)/BAUD) 
 
#if ( (BAUD_ERROR>1015) || (BAUD_ERROR<985) )
  #error Systematic baud error above 1.5% which is too high! 
#endif


void uart_putc(uint8_t data) {	
	while(!(UCSR0A & (1<<UDRE0)) );
	UDR0=data;	
	TEST1_HIGH
	_delay_us(100);
	TEST1_LOW
	_delay_us(100);
}

int main(void) {


	DDRD = (1<<PD2) | (1<<PD1);

	// UART0 init
    UCSR0B = (1<<TXEN0); 
    UBRR0H = UBRR_VAL >> 8;
    UBRR0L = UBRR_VAL & 0xFF;

	while(1) {
		uart_putc('A');
		uart_putc('B');
		uart_putc('C');
		uart_putc('D');
		uart_putc('E');
		_delay_ms(100);
	}

}