; uart functions

UART_INIT:

	; baudrate
	ldi tmp,
	out UBRRH,tmp
	ldi tmp,
	out UBRRL,tmp

	; enable
	ldi tmp,(1<<RXEN)|(1<<TXEN)
	out UCSRB,tmp

	; frame format

	ret

UART_RX:

	; get/store received byte
	sbis UCSRA,RXC
		rjmp UART_RX
	in tmp,UDR0

	ret

UART_TX:

	; transmit content of tmp
	sbis UCSRA,UDRE
		rjmp UART_TX
	out UDR0,tmp

	ret