Add disk inserted sensor pin interface option.

[tdaede]

"in" and "nin" can configure a pin to indicate the status of
the disk inserted sensor. This ignores the drive select pin.

This is intended to be used with the Sharp X68000 (with the
addition of additional hardware - on the X68000 this is gated
by the OPTION SELECT line).

[keirf]

How widely is this likely to be utilised in the X68000 community?

[tdaede]

I did plan to distribute the interface boards... maybe in the tens somewhere? There are people already using simpler adapter boards that require a manual switch to toggle eject status, but I think this is nicer. There is also a rpi based solution, but the interface boards for it are rarely in stock so I haven't been able to directly compare it.

I couldn't figure out a way to do it PCB-less just because the Gotek hardware doesn't have enough I/O pins (at least without invasive soldering).

FWIW the other changes that I'd want to make for X68000 is a PC-type hint for the .xdf extension (as on X68000 they are just img files) and triggering an eject via the MOR pin (optional, you can just push the button to eject when a motorized eject occurs). Maybe also .dim format (.img with a header, also useful for pc98)

[ejona86]

For me to look into later: I was interested in what sort of board adapter board this would take. I found https://nfggames.com/forum2/index.php?topic=6483.40 which links to https://gamesx.com/wiki/doku.php?id=x68000:adding_an_fdx68_to_x68000 and https://github.com/aotta/X68KFDUINO . There's also a no-microcontroller adapter in the middle of the forum thread.