Raven. A homemade Atari-like computer

[agranlund]

I just learned about this new soundcard in development and it looks like it's going to tick pretty much all the boxes with both GUS and SB (compatible) in one card.

https://pcmidi.eu/xtreme.html

Reading up on the Ensonique ES1869 revealed a very nice surprise.
Apart from all the normal Soundblaster stuff it adds the ability to interrupt and let you fill the DMA Fifo using PIO transfers, especially for systems that don't have or don't want to use ISA DMA..
This is crazy useful for Raven, and should reduce non-dma playback overhead quite a bit compared to standard SB.

Couldn't help myself and ordered a cheap old ES1869 based soundcard off ebay to play around with while waiting for that new one to become a reality

[PhilC]

@agranlund that's definitely an interesting card. I'll see how you get on with them and will go from there.

I'm think I'll end up with one high spec Raven and one that won't be cased that I'll use for testing and general breaking stuff.

[dml]

Couple of quick questions.

I have been gradually filling the BOM and mostly going well - but received a couple of incorrectly specified parts.

1) The ATF1508 - I seem to have a 10JU84 not 7JX84 (I think a 10ns device). Is this 'good enough', or 'not known' - should I try again to source the specified 7ns part?

2) Same situation for the ATF22V10C - I seem to have a 15ns part here, listed as 10ns. :/

Fortunately, the rest looks ok but these ones are kinda critical to the whole thing.

[PhilC]

@dml I'm using a 10ns 1508 at 80mhz so far without issue.

I had problems with the 15ns gal used for the ISA interface and changed that. I've found that an actual GAL22V10 7ns will actually run the ATF22V10C software without any problems, do maybe a 10ns will do as well if they are any easier to find?

[dml]

@dml I'm using a 10ns 1508 at 80mhz so far without issue.

That's helpful, thanks. I can at least start with that config knowing it can work.

I had problems with the 15ns gal used for the ISA interface and changed that. I've found that an actual GAL22V10 7ns will actually run the ATF22V10C software without any problems, do maybe a 10ns will do as well if they are any easier to find?

Oh actually have GAL22V10s here already! Not sure of the speed - I'll have a dig and see.

...I'll need to check it later. My cat is sleeping on exactly that one box, from of a wide choice of boxes.

[PhilC]

Just a quick question @agranlund, are you pretty much planning to stick with the ET4000 W32, or do you have plans for any other graphics cards with the Raven?

Edit:

And any other plans for Raven? I'm likely to takeine to Cyber legends this year all being well.

[agranlund]

Just a quick question @agranlund, are you pretty much planning to stick with the ET4000 W32, or do you have plans for any other graphics cards with the Raven?

I have a whole bunch cards of different makes and models here that I hope to find time to resume playing with at some point

At the moment, you should be able to use any VGA compatible card (*) and end up in a 640x480 mono desktop.
The next step would be to have the generic driver allow you to switch to 320x200x8bpp for games and so on.
(*) not a promise, I'm sure there are cards that don't work. I have tested quite a few different models though.


But after that, yes, I do want to make proper support for some other cards.
At the moment all that code is prototype/testing quality and far from ready to use, but I am able to make fVDI and NVDI drivers and had both of these running the desktop in 800x600x8bpp as a proof of concept on one of the cards (forgot which one I was playing with).

I think I'll end up with basic functionality for many cards and then pick one to add goodness to, and in time some kind of expandable framework should grow from all that - or that was the thinking anyways. Goodness being the stuff that is specific for each vendor/model -- things that isn't covered by the VGA or VESA1 standard. Ie; hardware acceleration being the most interesting.

Could also be that not much happens at all
There's a lot of different really fun stuff one can work on for Raven and I tend to pick whatever I fancy at the moment when I sit down to do something with it.

TLDNR: holding breath can be hazardous to your health, avoid that.

[mrbombermillzy]

At the moment, you should be able to use any VGA compatible card (*) and end up in a 640x480 mono desktop.
The next step would be to have the generic driver allow you to switch to 320x200x8bpp for games and so on.

In theory, setting generic VGA registers from on the card (which is the way @agranlund did it IIRC; are you using the BIOS emulation code you showed me, on the Raven?) should give at least the 320x200x4bpp on every old ISA card that supports IBM VGA fallback registers. There shouldnt be any need for unlocking extra registers or whatnot at this basic level.

However, Ive not touched on this for a while (I think my Dell 27" main monitor may be the problem), as I cant get the basic low res modes (less than 640x400) to display on my ET4k or M32, whatever I do, so cannot confirm this as 100% accurate yet.

[PhilC]

@mrbombermillzy ideally I'd like to see if I can make the basic Emutos driver work on all VGA cards at least as you say in basic VGA mode.

[mrbombermillzy]

I dont know what sorcery Anders' drivers may perform, but providing the standard IBM VGA registers are used, it should be just the video buffer base address that needs changing ($a000<>$c000 or something like that).