exxos's Atari, Amiga & retro forum

I don't have a short board but follow this with great interest anyway :)

@agranlund ROM board with RTC support looks very interesting, unfortunately my short ST has a board C070243 Rev.H, which can only work with 6x ROM and does not have a solder box for selecting 256k / 1M. So it probably won't be for me :)

But I'm still watching your progress and I'm looking forward to the next sequel. :twisted:

davemacblack wrote: 12 Nov 2020 16:50 @agranlund ROM board with RTC support looks very interesting, unfortunately my short ST has a board C070243 Rev.H, which can only work with 6x ROM and does not have a solder box for selecting 256k / 1M. So it probably won't be for me :)
But I'm still watching your progress and I'm looking forward to the next sequel. :twisted:

It's supposed to work on motherboards that don't have the 256k/1M jumpers but I don't know for sure until @PhilC has tested it :)
I tried it with my motherboard jumpered to 256k mode which should be equivalent as far as I understand.

Icky wrote: 12 Nov 2020 15:36 I'm with you too @agranlund, I have a short model too and am watching with interest, in particular am waiting to see the Phoenix Sparkalaphobia (FPGA Blitter) running in a short once we get the board done. :)

Yeah that's going to be super interesting :)

Hmmn.. the datasheet for ET4000 contained a reference design, plus I have a couple of ISA cards here to look at... so why not? :)
In all honesty I'm not sure this is the most sensible endeavour and it may amount to nothing, I still haven't built and tested the rev.C yet :lol:

If I do keep this up then it will probably use the following ICs:
ET4000AX, desolder from old isa card.
ATT20C490 ramdac, ICS2494 clock generator and 5118160 drams are plentiful on ebay, plus I already have them.

:lol: you do come up with some cool and almost random ideas for projects but what's more impressive us you complete them too.

Might have a couple of et4000s here too if it helps?

PhilC wrote: 12 Nov 2020 17:38 :lol: you do come up with some cool and almost random ideas for projects but what's more impressive us you complete them too.

Might have a couple of et4000s here too if it helps?

Haha yes thanks, I think I just like to try random things just to see if I can :lol:
I wonder what I'll do when I run out of room in the Atari (or when it finally caves in and dies from the upgrades :? )

I'm still not too sure about building an ET4000 into the blitter board. I think it will be fun and educational plus make the internals look cleaner but if the separate gfx card with the Rev.C board works fine I might stick with that and use the space for something else instead.

I am incredibly pleased with how this turned out! :yay2:
This is a lot better use of space than that old RF modulator.
RAL7038 turned out a tad brighter than the stock color but it's really quite close and good enough for the bottom part of the case anyway.
It's just great being able to plug the VGA and audio in/out directly to the machine!

The internal speaker is nice and deactivates automatically if I plug something into the audio-out jack. I'll probably add a volume control for the internal speaker at some point but for now I "hard coded" it to a low-ish level with a resistor.

The Dreamblaster X2 works but the level is very low so I'll need to boost the signal a bit. I have headers for hijacking the signal so at least I won't need to desolder the whole thing, a simple add-on board should be enough :)

This is awesome :)

I've enjoyed watching this evolution. Tis a thing of beauty.

I realise I'm in a minority fiddling with the short STM model but in case someone else finds it useful I will upload the gerbers and schematics once it has been tested to work correctly on a motherboard with no 256K/1M jumpers.

@agranlund

You're not that lonely. I have 3 pcs 2x rev. C and 1x rev.H and I am happy that you gave him so much life. The Atari 520STM was the easiest to buy due to the lack of an internal power supply and FDD. But this charm in it :) Your inventions strengthen it, and how correctly the ST-ROM (1M chip) works on revisions other than rev.I, it will be great

Many thanks for the work :)