Welcome

Adding support for the external memory expansions (up to four 1 MB expansions were possible) fixes MasterDOS, which is used by many other disks to boot (for example, the MOD players).

Just finished adding partial (some status codes for the wd17xx controller are still ignored) SDF image format to the coupe driver. This allows the original, copy-protected version of Lemmings to boot:

Haven't tested it much, but it seems to be fully playable.

Adding support for the 720k CP/M Pro-DOS format gets CP/M going nicely on the Coupe:

And we immediately use that to play games of course:

After some prior detection problems, B-DOS now correctly detects the SAMBUS real time clock. It writes values to the clock registers and expects to get them back - but the MAME implementation was ignoring writes and just returning the current time. After changing that, so that it returns the values written to it for some time, we get this:

It still hangs at the HD detection though, looks like the WD1772 controller needs to return some different values for it to fail (the HD controller is running on the same port as floppy drive 2).

I decided to take a look at the SAM Coupé driver, because I saw some weird unused code in the palette init that I cleaned up. After changing the video emulation to use the new scanline-based update features in MAME, adding proper vblank areas and using all that properly emulate the LPEN and HPEN registers we get from this:

To this:

However, currently most of the work is still cleanups, like the I/O ports. Major areas that still need cleaning up are the memory banking and video drawing routines. When the driver is in good shape, we can take a look at adding the missing border areas or features like the Real Time Clock and hard drives (or even tapes).