/* Disables the USART. 
Ensures that nothing is transferred while setting up buffers. */
void usart_spi_disable(USART_t *usart)
/* Disables the USART. 
Ensures that nothing is transferred while setting up buffers. */
void usart_spi_disable(USART_t *usart)
{
	usart_tx_disable(usart);
	usart_rx_disable(usart);
}