Is the IRQ pin on the MCC128 necessary for normal operation?

[dzajac]

My setup is using an MCC128 hat for general purpose data acquisition, as well as a separate hat for RS485-based sensors. I ran into an issue where the RS485 hat uses the Raspberry Pi's SPI1 interface, which conflicts with the IRQ pin (GPIO20) used on the MCC128. Is the IRQ pin strictly necessary for normal operation? If it is necessary, would it be possible to change which pin is used?

[Jeffrey]

Per the Developer, the IRQ pins on the 128 and 172 (both share GPIO20) are there in case we want to optimize transfers in the future, but we do not currently use them.  Perhaps you have another signal present on that pin from something else?