usart poll rx/tx

usart_poll.c

unsigned char serial_poll_recv(unsigned char *a_data, unsigned int a_size) {
	unsigned int cnt = a_size;

	while (a_size) {
		/* Wait for data to be received */
		while ( !(UCSR0A & (1<<RXC0)) );

		/* Get and return received data from buffer */
		*a_data = UDR0;
		a_data++;
		a_size--;
	}

	return cnt;
}


unsigned int serial_poll_send(void *data, unsigned int a_size) {
	unsigned int i = 0x00;
	while (i < a_size) {
		// wait until usart buffer is empty
		while ( bit_is_clear(UCSR0A, UDRE0) );

		// send the data
		UDR0 = ((unsigned char *)data)[i++];
	}

	return i;
}