exxos's Atari, Amiga & retro forum

Is there any method to install the BLiTTER in short 520ST?
thx

AFAIK nobody has ever done it. Probably would have to have a custom PCB done to fit over the CPU, then some tracks cutting to GLUE to route the bus grant stuff about.

I think I've seen such mod once... you need to cut just 2 tracks, as in STf you have to desolder only 2 bridges. Just 68 wires, and you're done ;)

You must really want a glitter to go through all that trouble. I think I would look for a st that has a pc board that will accept a glitter socket or something that comes with a blitter such as a mega. Chances of successfully adding a glitter to a 520 would be small. Just my thought. :mrgreen:

As an owner of a short 520ST I'd really kind of think that trying to add a Blitter is a really long road you wouldn't want to go down. It just wasn't designed with it in mind.

I'd suggest you'll probably be better of leaving it as is and getting an STF/M with space to add a Blitter or one that's already installed.

True, would be easier to use 1040 instead. But if I would like to go the easy way, I would just leave retro computers :)
From all my Atari collection, 520ST looks the sexiest. I have a secret plan to install there FPG blitter.
Colleague from our local forum Atari.pl had short 520ST with the BLiTTER's daughterboard. Unfortunately sold it a few years ago.

Cyprian wrote: 26 Jul 2019 10:22 True, would be easier to use 1040 instead. But if I would like to go the easy way, I would just leave retro computers :)
From all my Atari collection, 520ST looks the sexiest. I have a secret plan to install there FPG blitter.
Colleague from our local forum Atari.pl had short 520ST with the BLiTTER's daughterboard. Unfortunately sold it a few years ago.

If you do find a way, then I fully expect documentation of the entire process on this forum ;)

oki :)

I have added a blitter to my 520ST. In fact, the PCB's arrived from china just today so I was quite excited to see that it actually worked!
Of course, the sane thing to do would be to just get an STE, but I like this machine - I've had it since 1985.
Thank you Exxos for stocking and selling loose Blitter chips, it really came in handy :)

The board I made goes in the CPU socket and provides blitter, adress decoding for 2.06 roms and a 44pin IDE port.
Of course, the ST doesn't have a socketed CPU so it has to be desoldered and the socket added.
I'm waiting for delivery of a CF card adapter before I can test if the IDE port works or not.

I'll put the schematics somewhere for download once I've had a chance to test it more properly :)

I'm thinking the next upgrade will be a card for where the RF modulator used to sit. To provide a VGA connector and an audio jack, and perhaps an internal speaker.

All signals except for INT3 are available on the CPU bus so if you make a custom PCB that goes between the motherboard and CPU there is no need to cut traces on your motherboard - the only thing you need to do with the ST motherboard is solder a wire from pin 25 on the 68901 (or resistor R4) to wherever you expose the blitter interrupt on your board.

Of course, you would need to desolder the CPU and add a socket which in itself is a bit of a pain...

R4 on the ST motherboard is 4.7k while it's 1k on the STFM and STE, but it appears to work fine for me even without replacing that resistor - I have only had a chance to test with Gembench so far though.

--Anders