; uart functions

; default uart settings
; infdef UART_BR_H
.equ	UART_BR_H	= 0
; infdef UART_BR_L
.equ	UART_BR_L	= 25

UART_INIT:

	; baudrate
	ldi uart_rxtx,UART_BR_H
	sts UBRR0H,uart_rxtx
	ldi uart_rxtx,UART_BR_L
	out UBRR0L,uart_rxtx

	; enable
	ldi uart_rxtx,(1<<RXEN)|(1<<TXEN)
	out UCSR0B,uart_rxtx

	; frame format -> 8n1
	ldi uart_rxtx,(1<<UCSZ00)|(1<<UCSZ01)
	sts UCSR0C,uart_rxtx

	ret

UART_INT_RX_INIT:

	in uart_rxtx,UCSR0B
	sbr uart_rxtx,(1<<RXCIE0)
	out UCSR0B,uart_rxtx

	ret

UART_INT_TX_INIT:

	in uart_rxtx,UCSR0B
	sbr uart_rxtx,(1<<TXCIE0)
	out UCSR0B,uart_rxtx

	ret

UART_RX:

	; get/store received byte
	sbis UCSR0A,RXC0
		rjmp UART_RX
	in uart_rxtx,UDR0

	ret

UART_TX:

	; transmit content of uart_rxtx
	sbis UCSR0A,TXC0
		rjmp UART_TX
	out UDR0,uart_rxtx

	ret