Raven. A homemade Atari-like computer

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mikro
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Re: Raven. A homemade Atari-like computer

Post by mikro »

Apparently it takes only one curious person to make everyone blown away. :-)

Imagine someone like @agranlund in the peak times of the Hades or Milan; people would be buying those at a much higher rate IMHO. In those times, all you could hope for was nice graphics (S3/ATI, IIRC Milan had some kind of tool to display TV signal in GEM window), some really basic XBIOS API for SoundBlaster (MilanBlaster/GSXB), basically just making it barely Falcon-compatible, and ... and I can't think of any else "killer app".
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stephen_usher
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Re: Raven. A homemade Atari-like computer

Post by stephen_usher »

But back in the day you couldn't order a short run of PCBs designed on computer for relatively small amounts of money and have them delivered within the week.

Rapid prototyping, manufacture and delivery have completely changed the game.
Intro retro computers since before they were retro...
ZX81->Spectrum->Memotech MTX->Sinclair QL->520STM->BBC Micro->TT030->PCs & Sun Workstations.
Added code to the MiNT kernel (still there the last time I checked) + put together MiNTOS.
Collection now with added Macs, Amigas, Suns and Acorns.
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DoG
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Re: Raven. A homemade Atari-like computer

Post by DoG »

Hmm. Those memory chips on the SIMM ain't cheap... :o
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agranlund
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Re: Raven. A homemade Atari-like computer

Post by agranlund »

nokturnal wrote: Sun Jul 07, 2024 9:41 am Yes, OPL2 has different timings for setting address data, because it's internal clock is much slower than on OPL3.. From my notes:

If cpu is much faster we need to introduce wait states. I generate nops in rept depending on cpu clock(8/16MhZ), but I will need to exchange it to something more elaborate in the future.
Yep, the vgmslap playback routine already accounted for different delays depending on the detected chip but it ended up being a case of sometimes working and sometimes not so I unscientifically bumped those values to make the OPL2 happy.

That old original MS-DOS code wasn't very elaborate in the delay timing either..
It did ISA I/O reads in a loop which isn't very accurate on a PC either since there isn't really a hard specification for that clock, other than the "somewhere around 8mhz or so" that the industry eventually agreed on.
I suppose it doesn't really need to be super accurate for this purpose as long as the delays are not too short but I have it on a todo to replace that timing code with something more sane :)
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agranlund
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Re: Raven. A homemade Atari-like computer

Post by agranlund »

DoG wrote: Sun Jul 07, 2024 10:59 am Hmm. Those memory chips on the SIMM ain't cheap... :o
They are most certainly not.
I think you're looking at around €50 +VAT to make a stick of 16MB, which is bonkers compared to DRAM.
I'm not sure of an exact BOM cost for the motherboard, I'm guessing at €200+ excluding the IC's that are out of production?
The whole thing is quite expensive to build and I imagine a board like this would look very different if it was made by a company, or made with a purpose of being a thing to be sold.

For me with the intent of making a one-off homemade computer thing for myself, and being much more interested in getting to work on software rather than the hardware, that stuff didn't really matter too much.
I'm quite certain it's visible in many other design and component choices too where I prioritised easy (and color) over price.

But then again, everything about this is dirt cheap compared to the money-pit sitting in the garage :lol:
Oldskool
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Re: Raven. A homemade Atari-like computer

Post by Oldskool »

agranlund wrote: Sun Jul 07, 2024 11:44 am
DoG wrote: Sun Jul 07, 2024 10:59 am Hmm. Those memory chips on the SIMM ain't cheap... :o
I'm guessing at €200+ excluding the IC's that are out of production?
I just filled in Mouser for all the stuff incl. programmer ATDH1150-USB = 410.61 euro
And I pushed on the order button. :D

PCB’s = 150
And then you also need the other ic’s. Probably 30 euro. (excl cpu)
And a 060LC = 100 Full = 400
And a PSU and a case = 150
GUS = 175
OPL card = 75
Videocard = 50 - 300
Network card = 25

1165 - 1685 :o :o :D :D

So maybe good to know..
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agranlund
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Re: Raven. A homemade Atari-like computer

Post by agranlund »

I've had this in the drawer for a while and thought it's time to check it out. Such a cool little card!
I'll need to revisit the mod player to enable code for the older GF1 chip before I can hopefully get some sound out of it but at least it looks like I can communicate with the card and it appears to detect the emulated GUS.

I'm starting to question the decision of having Midi on the motherboard, every PC soundcard pretty much has that anyway.. oh well :lol:
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Oldskool
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Re: Raven. A homemade Atari-like computer

Post by Oldskool »

Yes also bought this version. They are available via local europa and uk stores now.

Would be cool if this would do the midi. Then you would have the gus, opl and midi via the wavetable.
No opl3 yet…. Seem to be struggling with the emulation speed. But who knows in some time..

https://www.serdashop.com/
Also for other retro sound stuff ofcourse

https://shop.flamelily.co.uk/picogus
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agranlund
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Re: Raven. A homemade Atari-like computer

Post by agranlund »

Oldskool wrote: Sun Jul 07, 2024 1:22 pm Yes also bought this version. They are available via local europa and uk stores now.

Would be cool if this would do the midi. Then you would have the gus, opl and midi via the wavetable.
No opl3 yet…. Seem to be struggling with the emulation speed. But who knows in some time..
Yep, it's such a cool project and I think it will just keep improving over time with firmware updates. It seems quite active.
I didn't realise it was OPL2 only for now but you're right - I flashed it with the Soundblaster firmware and it only works as OPL2.
Still pretty cool though, and it sounds great. I can't really hear any difference from that real OPL2 card I have :)

It would have been nice to have GUS + Adlib in the same firmware but maybe there's not enough horsepower for that.
Have to check the midi at some point, especially with that wavetable header.
nokturnal
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Re: Raven. A homemade Atari-like computer

Post by nokturnal »

@agranlund You could look into minimal timing testing of OPL2 with c64: https://c64.xentax.com/index.php/15-tes ... ite-timing. They tested rapid voice on/off to check data write delay for instance... Otherwise you will burn cpu cycles, but probably it doesn't matter much on 060 ;)..
saulot/[nokturnal]
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www: https://nokturnal.pl
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