How do I have to configure the RX-Pin of a UART? Should I configure it with internal pullup resistor? This is what I have done in earlier projects on other controllers.
For a XMEGA it will look probably like this:
PINnCTRL.OPC=0; // TOTEM (reset value)
PINnCTRL.OPC=3; // PULLUP
Or does configuring such a pin as a UART RX overwrite this setting?
The application note AVR1307 does not mention this and the example code does not use PINnCTRL. Thanks in advance for any comments.
Edit: My intention is to avoid dummy interrupts if the RX signal is disconnected. An alternative is of course an external pull up resistor...