Raven. A homemade Atari-like computer

[agranlund]

I doubt you would even see the tests running going that fast :lol:

They do flash through pretty quickly yes.. :lol:

[agranlund]

Install NVDI5 with the screensys driver in the GEMSYS Folder disable by rename these to *.syz ...

NVDI must run after sta_vdi.prg and you becomes 200% speed from the Nova driver ...

Yep, I run it like that.
And all thanks to you I must add!

Every time I've gotten stuck and needed to search for some VGA related information I always found a forum post from you that helped me :)

Same today actually when I needed to figure out how to memorymap the card to fit my hardware + Nova driver and get access to the full 2MB. In the end I found a VME->ISA schematic that you had posted some time ago and that cleared everything up.

[Oldskool]

Ok, so now it's going to be interesting to see how fast I can push the bus. It's still running with waitstates adjusted for the ET4k.

Very cool to see accelerated graphics on the Raven. Et4000 does not have fancy accelerated functions. On raw isa busspeed I’m not sure if a mach32 is faster (on a isa bus). Et4000 could be faster on raw busspeed throughput at least on a pc in dos it probably is (fps DOS doom, quake). From Phil’s computer:

IMG_1755.png

I read somewere that a Raven is considered the smartest bird on the planet. :)

[agranlund]

Very cool to see accelerated graphics on the Raven. Et4000 does not have fancy accelerated functions. On raw isa busspeed I’m not sure if a mach32 is faster (on a isa bus). Et4000 could be faster on raw busspeed throughput at least on a pc in dos it probably is (fps DOS doom, quake). From Phil’s computer:

I agree, they're about the same on raw busspeed on ISA and the ET4000 is an excellent card.
The Mach32 really shines with the acceleration features, and hopefully maybe a potential for driving it further out of spec.
Granted, this is on a tuned for the purpose PC but he gets some pretty impressive results out of that old card (35 fps vs stock ~19)



One big drawback I noticed with the Mach32 is that you can't configure a 320x200x8bpp resolution with the tool that comes with the Nova driver.
The hardware is obviously fully VGA register compatible so it's a bit curious why the resolution tool isn't exposing double-scan and half-clock settings for the Mach32. It does for ET4000, so I'm sure there has to be a reason.

I'm going to try to and reach out to Idek and see if he knows, and if it's a major hassle to add that in.
It's nice and clean to use the Nova API for switching to premade resolutions, and I rather do that than hit VGA registers directly in own programs.
That 320x200 mode is quite important for my ST emulator in full screen, as well as for pretty much any SDL port such as Doom etc.

[Oldskool]

A pity that there are no Atari drivers for the very cheap CL isa cards (542.. or so). These combine bus speed and acceleration features. Amiga Picasso card uses these as well I think. Et4k is also very common. I think I have like 3 or 4 of them in the attic.

Mach32 is like the “White Raven” among the ISA cards and collectible. Probably it can fetch around the Raven’s total BOM cost on eBay.

Seems he also did the OC on the ET4000:

(And this guy has the et4000 running at 16mhz
https://dosdays.co.uk/topics/retro_revi ... 00_pt2.php)

et4000oc.JPG

[Steve]

Mach32 is like the “White Raven” among the ISA cards and collectible. Probably it can fetch around the Raven’s total BOM cost on eBay.

Maybe I was silly to sell one for £50 on this forum not to long ago :) but I had no use for it. I don't like owning things I don't use.

[frank.lukas]

Et4000 does not have fancy accelerated functions ...

There are Nova ET4000/W32i Driver. W32i has a Blitter and is a little bit quicker than the AX chip but the Nova driver not use it I think. Write to Idek because he supported the Nova Driver ...

[agranlund]

There are Nova ET4000/W32i Driver. W32i has a Blitter and is a little bit quicker than the AX chip but the Nova driver not use it I think. Write to Idek because he supported the Nova Driver ...

Looking at the Mach32 datasheet I think it now makes sense why 320x200x8bpp is not supported by the driver.
It looks like it puts the card in 8514-compatible mode which makes perfect sense.
And as far as I can see those regs don't have any capability of getting the card into such a low resolution, but I'm very far from an expert on this area.

The hardware can do it of course, but I belive it needs to be switched over to VGA-compatible mode first so that resolution can be set as usual through the normal VGA registerset.

I wrote Idek to get some confirmation - it's certainly not impossible my assumptions are completely off.
It's also quite understandable if it's way too much effort to make the driver and tool support and switch between both modes of operation.

If not I'll start fiddling with making my own enter/exit "Mode13h" code for fullscreen stuff.
I'm naively thinking it should be trivial to get it into the mode, more worried about coming back out, or upsetting the driver by going behind its back.

[agranlund]

A pity that there are no Atari drivers for the very cheap CL isa cards (542.. or so). These combine bus speed and acceleration features. Amiga Picasso card uses these as well I think. Et4k is also very common. I think I have like 3 or 4 of them in the attic.

I agree! Those CL cards would be nice.. both fast and cheap.
And probably less vendor-specific variations to consider because all the important bits are built into the one single chip?


It looks like Et4k is going up more and more in price too, and it feels like you have to know a lot and/or be lucky to get a variation that is compatible with either Nvdi-vga or Nova?
I just bought a random bunch back when I mounted one in the ST, I think 2 or 3 ended up being compatible.
Good thing they where pretty cheap then.

Mach32 is like the “White Raven” among the ISA cards and collectible. Probably it can fetch around the Raven’s total BOM cost on eBay.

Yeah, pretty much :(

[Oldskool]

It looks like Et4k is going up more and more in price too, and it feels like you have to know a lot and/or be lucky to get a variation that is compatible with either Nvdi-vga or Nova?
I just bought a random bunch back when I mounted one in the ST, I think 2 or 3 ended up being compatible.
Good thing they where pretty cheap then.

Yes Mikro made me aware of this indeed. Even these common cards are getting expensive. :( Will be sending him one. I hope it will work for him. It seems to be a gamble on compatibility when I understand your feedback correctly. (RAMDAC I assume..). CL is still cheap on eBay…

But Ok enough of the negative. We now want to see cool things on the Raven😀.