I'm using a XPro4 breakout board which has wiring for limit switches. I've got the switches connected to the board but no display on the Mach3 software. I get a tone from the computer when switches are depressed but no interrupt from the software. I'm sure it's my own stupidity but what do I need to do to rectify the situation?

Common faults are:-

Board is not enabled.

Boards works at 3.3V,  Mach needs 5V.

Board needs more than one power supply.

Check if inputs need to be at 0V or 5V.

Maybe check the obvious and check the ports and pins to make sure they are enabled