Lobo Max 80 Emulator

[EtchedPixels]

I have added an initial attempt at a lobo max 80 emulator to EmulatorKit (https://github.com/EtchedPixels/EmulatorKit)

It's fairly basic and I still need to knock some bugs out of the WD17xx (and clone) emulation code. It is however good enough to run CP/M 2 and CP/M 3 off floppies.

Next steps are to reconfigure CP/M 3 for a SASI hard drive and see if the standard SASI emulation code I wrote can handle it. UVC however seems a bit weird and totally undocumented.

Currently it gets disk errors trying to run the various TRS style DOS (all of them give error 0x11 for no obvious reason yet)

There are a few mysteries too
1. Can you write through to the RAM behind the keyboard mapping ?
2. Does the write through always go to bank A chunk 1 or does it depend on the mapping ?

 

[lowen]

Currently it gets disk errors trying to run the various TRS style DOS (all of them give error 0x11 for no obvious reason yet)

A MAX-80 emulator; fantastic!

The error 0x11 is a directory read error. TRSDOS-style operating systems use deleted data address marks to mark sectors in the directory track; this is partly to provide rudimentary protection for that track, since 'regular' sector reads and writes will error out if DDAM is present, and special 'system sector' reads and writes, that will neither read nor write sectors with regular DAMs, are used for directory sectors.

You mentioned the WD FDC emulation needs a bit of work; to run a TRSDOS style (like LDOS or MaxDOS 6) you'll need DDAM support in your FDC emulation.

 

[EtchedPixels]

And if I guess which track and fake DDAMs for the track...



Not sure when I will have time to teach the floppy emulation properly about DDAMs, that would also mean teaching it to use JV3 or similar not just raw data.

Looks like maxdos 6 is not Y2K compliant 8)

 

[lowen]

The 'standard' emulation disk image format for TRS-80's is the DMK, although emulators that can use IMD and HFE are available. DMK allows FM and MFM to coexist on the same disk, even intratrack. I don't know how much MAX-80 software used FM, though. JV3 would be a good start.

Great work,as usual for you, by the way! (You may or may not remember, but back in Linux 2.0 kernel days you helped me with building a kernel with the Media Vision ProAudioSpectrum 16 driver back in 1997.....)

 

[EtchedPixels]

Done a bit more work on this, fixed some disk motor assumptions and enabled SASI hard disk. It's now running nicely with my CP/M C drive as an emulated CDC Wren II.

Only the very late CP/M disks seem to have SASI support and only for a single drive at ID 0. The older makesys only knows UVC which I've yet to entirely figure out. Confusingly the UVC is 256 bytes/sector but the SASI expects 512.