Raven. A homemade Atari-like computer

[Atarian Computing]

@Atarian Computing , give this updated rvbios.prg a try and see if that works for you too.
I'll then update the release zip tomorrow or so.

rvbios.prg.zip

My disk is in a bit of a state at the moment but I threw in a fresh minimal MagiC install and did some quick tests:
- Used XControl.acc to see that time/date was correct and could be changed
- Made a new file with QED to verify new file time was correct
- Did the same in EmuTOS to verify new bios didn't break it

Sweet. That did the trick!! Thanks.

I found Truedisk 2.3 in my archives, if you're interested.

Also, I'm happy to report that Geneva and Neodesk are running perfectly on the Raven.

[Mikerochip]

Inspired by @Mikerochip I decided to finally test the i2c expansion header.
Have had an LCD module for exactly this purpose just laying around for ages now.

tada!

Outstanding!!

Next step.... outputting bios/debug messages? Be nice to have a diagnostic boot up series of messages... :lol:
Well. Not just diagnostic.
A serial boot output. Even if it's not terribly useful most of the time, it looks impressive!!

What were you planning on using it for?? :P

Also, I'm happy to report that Geneva and Neodesk are running perfectly on the Raven.

Wow!
That's almost everything, except mainline Atari TOS.

So, MagiC, MiNT, EmuTOS and now Geneva. (Which I presume runs under EmuTOS?)
Anyone tried MultiTOS?? :D

I wonder what it'd take, to get TOS 3.06 working for the Raven?
(I remember reading that Thorsten Otto had 3.x building from source, and, also had a Hades build too)
Yeah.
https://github.com/th-otto/tos3x

[agranlund]

What were you planning on using it for?? :P

I have absolutely no idea! But at least i2c expansion header has been tested now :)
There are plenty of different i2c devices available. With a i2c GPIO expander one could perhaps make some blinkenlight output and/or read inputs from a bunch of physical switches (for what, I don't know).
Or hook up an accelerometer sensor, shake the computer around and have fun reading out the values :lol:

[agranlund]

More LCD fun. Should eventually become some kind of library rather than just a test app, probably.



Other than the flashy fun, one good thing that came out of this experiment is that it revealed there is some kind of issue when hammering i2c constantly like this.
Leaving it on like this for a long time will eventually crash my machine. Gut feeling says something might be borderline in the base i2c code or that it hits the lcd too fast/often (that bus is software bitbanged)

The only thing using that bus so far has been the rtc/nvram and that's very sporadic and low usage.

[Atarian Computing]

I have a couple of questions about the PicoGUS, which I installed yesterday, hoping to document Raven sound.

I also have the X2GS SE card
I have Logitech Z533 speakers with three non-switchable inputs, meaning that all inputs are "mixed" together. I have one input connected from the YM output on the Raven and another from the PicoGUS.

1. On the Raven, what's the difference between GUS and SB modes?

The only difference I've seen is that MXPlay will crash with MOD_ISA.MXP, when in SB mode, crashes with OPL_ISA.MXP in GUS mode. GUS mode is the only way I can play back MODs in MXPlay, and JAM will play in either mode, but no sound is output.

2. Is MPU401.PRG always required to playback MIDI from the wavetable card?

3. Would I (theoretically) be able to use PicoGUS and the X2GS SE for MIDI sequencing without cables using C-LAB or Notator or whatever the big hitters were?

[agranlund]

The short answers about how it effects the current situation from a usability perspective:

1. I'm no expert on the PicoGUS specifically, but:
The mxplay/jam mod player was written for GUS so it requires a PicoGUS to be in GUS mode.
PicoGUS in GUS mode does not emulate a SB (and does not provide OPL emulation. I'm not sure if it even emulates MPU401 midi in that mode)
When it is in SB mode, you get SB, OPL and MIDI for sure. But no GUS.

I'm unsure if you can fit two PicoGUS's in the same machine (individually configured as SB and GUS).
PicoGUS acting as an affordable GUS, in combination with some cheap SB clone card for SB+OPL+MIDI is probably an easier way to get all of the good stuff at once.
The clones are a better choice than the real SB cards with their hanging-midi-note-bugs anyway :lol:


2. Yes (*not really, but for the sake of it, let's say yes)

3. Theoretically yes. In practice, it will depend on how the application was programmed.


And the longer boring answers:

1:
From a programmer perspective. It's works almost identical to how it does in MS-DOS.
You can read/write (any) soundcard's registers exactly the same way as you would in MS-DOS.
Using isa.h you'll even get inp/outp functions so the porting effort is rather minimal.

2:
- By default, standard Atari XBIOS midi goes to Ravens midi-out jack.
- MPU401: routes Atari XBIOS midi to an MPU401 device on the ISA bus.
- OPL_MIDI: routes Atari XBIOS midi to a software synth, which plays back on an OPL device on the ISA bus.
(It sounds fairly similar to the default opl-based midi software synth in early Windows versions).

A program could of course output midi to an MPU401 device by programming it directly, even if the MPU401 driver is not used.
Some program that is using Atari XBIOS midi would in that case output its midi to the Raven midi-out port.

Here, one would ideally want to have some kind of midi device manager that lets the user easily select where "system default" midi gets routed.
Same as you had in Windows back then. And probably today too?
A control panel CPX maybe.


3:
- Assuming then that the application in question is using Atari XBIOS to output midi and does not go through the ACIA hardware which is not there.
From the midi software I tried it seems a lot of them appears to ignore the Atari API and goes direct to hardware.
For something like Cubase it could certainly be possible to make an MROS driver that talks directly to ISA MPU401, or probably better, goes through the Atari XBIOS interface.


And the even longer:

There is currently no shared sound-system.
And also no XBIOS sound driver for compatibility with STe sound through the Atari XBIOS.

Each of the programs I made where done by directly programming for a specific sound hardware. A'la MS-DOS, or you know, Atari.
The mod player for mxplay was done to try out programming the GUS.
Doom: SB + Midi or OPL
Tyrian: SB + OPL
Quake: SB

The ESS cards are SB compatible but has custom extensions which should make them much better suited for Raven compared to SB and I really want to get around exploring that.
There's no getting around the fact that GUS is better than all with it's hardware accelerated everything but it's also much more complex to program for.

But, the big elefant is that some kind of soundsystem would be great so programs wouldn't need to code specifically for each type of device.
Atari XBIOS would be a good start for compatiblity reasons, but that interface is made for very simple hardware in comparison and too limiting to take advantage of the more advanced stuff PC's had available with their ISA cards. Thinking especially about GUS and AWE.

Something in the spririt of DirectSound but simpler would be nice. Ie; automatically take advantage of hardware-mixing, usage of sound-ram, whatever exists, and this without a game/program having to know any details about what card(s) are in the machine.

[agranlund]

Oh, and there is always this newly made soundcard. Which looks like it contains everything anyone would want in a single card.
(With the caveat that I haven't actually gotten around to test mine yet. But on paper it looks like the perfect card for a retro-PC build or Raven if number of free ISA slots is an issue)

https://pcmidi.eu/xtreme.html
It's not exactly cheap though..

[DoG]

https://pcmidi.eu/xtreme.html
It's not exactly cheap though..

Wow! I looks like that page was built 1999 :shock: :D

[Atarian Computing]

Thanks so much for the comprehensive reply @agranlund. It all makes sense now. I have a lot to learn about PC sound from the 90s. Dad always had a PC since the XT days but I was happy with my STE and hardly touched them at all.

I tried Notator and Cubase. Notator would not even launch properly. Cubase loaded up fine and let me load a midi file but I couldn't get any sound output. I tried different settings but it probably is as you suspected with the ACIA and all.

I only have one remaining issue with sound it seems. Everything works apart from not having the SoundBlaster option in ScummST at all. I have Atari YM and a bunch of weird sound options. @kodak80's post here: viewtopic.php?p=132283#p132283 shows there being a SoundBlaster option. I wonder how to get it there. I obviously have the PicoGUS in SB mode, and Doom works just fine with SB sound. Am I missing something?

[luciodra]

Thanks so much for the comprehensive reply @agranlund. It all makes sense now. I have a lot to learn about PC sound from the 90s. Dad always had a PC since the XT days but I was happy with my STE and hardly touched them at all.

I tried Notator and Cubase. Notator would not even launch properly. Cubase loaded up fine and let me load a midi file but I couldn't get any sound output. I tried different settings but it probably is as you suspected with the ACIA and all.

Which version of Cubase can you run? I'd like to try it but I can't at the moment. A few months later I managed to start it, but then...