I'll second support for the VIPER System 1 keyboard. It was actually built directly into the RAM expansion, and should work on VIPERSoft BASIC and I believe even the regular BASIC versions without needing a driver or anything.
Thanks, I'll try to tackle this at the same time as I tackle the Blue Ram Keyboard. One thing that would be very helpful is to know how the keyboard matrices in both keyboards are laid out. Specifically, which row/column in the key matrix each key maps to, and in the case of the Blue Ram Keyboard, which pins in the expansion ZIF socket map to which rows/columns of the keyboard matrix.
The other thing that comes to mind is cartridge hot swapping. You should be able to remove one cart and insert another without resetting the system. The software list includes a bunch of BASICarts, which were BASIC programs converted into cartridge format. You need to swap the BASICart and the BASIC cartridge to run them.
This is not easily doable due to the need to reset the emulated machine when changing slot devices, but I'll throw some ideas around with Vas and see if we can come up with a solution.
The Music Maker cart includes a tape interface. As far as I know, it's identical to the 2000 baud interface in the BASIC cart.
If it is identical, then getting it working should be as simple as copying the line of XML that I added to hash/astrocde.xml into the entry for that cartridge, too. Can you point me at any tapes that I can use to test loading?
This is really reminding me of all the surprising things people managed to make this system do--often just one or a few people selling software and hardware through newsletters. I don't even remember how all of it works, but we'll try to figure it out if you want more details. We'll have to think about what would even make sense to emulate. Like, I archived a driver for the Blue RAM Modem, but I have no idea what you could do with it if you emulated one. There is a little bit of light pen software.
If we have schematics and appropriate documentation, why choose? I'm happy to take a crack at emulating any peripheral that has sufficient documentation. With enough effort, MAME could become the go-to emulator for Bally Astrocade emulation.
MAME doesn't currently have a way of handling microphone input, but I can think of a couple workaround that would allow emulating the device in the meantime, assuming documentation and tapes can be found.