Can't use iox.in and iox.out as input at the same time

[JoA-RHU]

Hi,
I'm using a Duet3 6HC, firmware 3.5.2, and I'd like to use both io0.in and io0.out for X and Y endstops but I can't make it work. I've NC microswitches wired between GND and io0.in/io0_out and my config is the following:

M574 X2 S1 P"io0.in"
M574 Y2 S1 P"io0.out"
M574 Z2 S1 P"io1.in"

For some reason, both inputs are constantly "triggered" (axes name with green background in DWC).
I thought it could be related to the fact that io0 is shared with UART (despite not using it), so I tried on the io1 header but got the same result.

Am I missing something? Should I wire the switches differently? Use invertion / pull-up (! ^) ?
Any help would be appreciated. Thank you!

[dc42]

@JoA-RHU check that you don't have a M575 P0 command in config.g. That.will switch the port into UART mode.

When using a io_out pin as an input, you need to either enable the pullup resistor using the ^ character at the start of the port name, or use an external pullup resistor to +3.3V.

[JoA-RHU]

@dc42 I enabled the pullup resistor for the io0.out pin, (and I found out a bad crimping contact for the X endstop... ^^').
Everthing works fine now. Thank you David.