exxos's Atari, Amiga & retro forum

Nice! How did you connect the busgrant via the glue ?

agranlund wrote: 04 Sep 2019 00:23 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 :)

great job!
do you have a spare board?

:bravo:
Wow, that sounds like a great solution/product.

I have a few STF models (5 I think) & all but one have no blitter socket/traces available so something like this would be a great way to add a blitter (not to mention the TOS 2.06 & IDE support).

Please keep us posted with any further progress.

Nice! How did you connect the busgrant via the glue ?

The board sits between the motherboard and CPU so signals can be rerouted to pretty much match the STFM/Mega/STE schematics.

Atari ST: CPU (BG) <-> Glue (BGI)
Atari Mega: CPU (BG) <-> Blitter (BGI) / Blitter (BGO) <-> Glue (BGI) <-> VME (BGO)

Blitter expansion:
CPU located on expansion board (BG) <-> Blitter (BGI) / Blitter (BGO) <-> expansion board to ST connector (BG) (which goes to Glue BGI as per the ST schematics)

That's the gist of it, same type of deal for the bus ack. Also some pullups.

do you have a spare board?

I want to test it properly on my machine before releasing the sources, then anyone could make a board (I'm not interested in making and selling these).
Don't expect anything in the immediate future though as I'll be away from home in the coming week.
At the moment I have only tested Gembench on Tos 2.06 and I would want to try some blitter enabled games as well.
(It does appear Emutos is no longer booting so I'll have to look into that - my gut reaction says it probably stops at ide detection and it might just be PLD firmware if I'm lucky.. but I'll know for sure in a week when I get time to debug it)

I do have 4 spare (unpopulated) boards though, so if it turns out everything is fine then I guess those could be had.

Cheers,
--Anders

Damn, son! Color me impressed!

Very nice. :) :)

Amazingly, everything seems to be working fine on the first revision of the board. No bodge wires necessary.
Tested with Tos 2.06 and EmuTos built from latest source on github.

Was cool to be able to play Giana Sisters with proper scrolling in P.Putnik's blitter enhanced version :)

The IDE interface works fine and it's pretty awesome to have a compact flash drive in that old machine.
Although EmuTOS's IDE detection takes ages if there is no drive connected to the IDE interface - when a drive is connected it starts up pretty much instantly like normal.
This problem does not exist on Tos 2.06, nor in EmuTos when a drive is connected, so I am going to go ahead and ignore that issue.
(RF-Modulator removed. That space is needed for another work-in-progress board)

Unfortunately, my board is not playing nice with Exxos 4Mb RAM upgrade...
I ended up having to take a chunk out of the RAM board to get them both to fit - luckily that part of pcb has no traces so it was quite a safe operation with a dremel.
If I end up making a new revision of my board I need to adjust it so it fits without having to molest neighbouring expansions :)


The old 520ST is certainly improving! Next on the horizon is to build or buy a TF534 and see if I can do something about those CPU speed numbers.
Not sure what people have already tried, but I'm thinking we should be able to use the PMMU to map the TOS region to onboard ram, alternatively just copy it and run it from there (the source for SELTOS is available so I'm thinking this could surely be modified to relocate TOS to altram instead of stram)


Anyway, I will packaged up and place the sources for the blitter board for download in the coming week or so.
It's all through-hole components so it's really easy to build. If you only want glitter and don't care for ROM decoding or IDE interface then you won't even have to program a PLD.
The CPU will need to be desoldered from the motherboard though and that is quite a hassle.

I made the sources available here: http://www.happydaze.se/stblitter/
Go nuts, but don't blame me if your Atari explodes! :)

great.
Do you still need your (mounted one) own?

Do you still need your (mounted one) own?

Yes, I will be keeping that one even if it may eventually end up in a drawer sometime down the line.

I had a look at what parts I have available at home and I can build 2 more of these, maybe possibly 3.
So if you want one it's yours for £40 + shipping.
You will need to get a Blitter chip from somewhere yourself though (hint: Exxos store).


A bunch of disclaimers:

- It is not plug-and-play!
* You need to de-solder the CPU from your Atari motherboard, and solder a CPU socket in its place.
This can be quite a task! (a little less so if you don't mind destroying the CPU in the process but then you would need to get another one..)
* You need to solder wires from the card to the motherboard (1 for blitter, 1 for IDE, 2 for ROM decoding)

- The IDE port is NOT buffered. I use a Sandisk CF card, with the CF adapter directly plugged into the board, and this works fine for me.
Your mileage may vary, especially if you have a cable between the board and CF adapter.
This is the CF adapter I use: www.amazon.co.uk/dp/B000OCY80C?ref_=pe_1365641_54848841
I use the HDDriver drivers from Uwe, but P.Putniks IDE driver should also work.

- There are clearance issues when using this card together with the Exxos 4MB Ram upgrade. You have two different options for solving this:
1) Cut a small chunk out of the RAM upgrade board (carefully! make sure you don't cut where there are traces on the board!)
2) Stack an extra CPU socket on the motherboard to gain some height for the Blitter upgrade board. It looks like that will give you the clearance you need (it's hard to tell for sure because I had already modified my RAM upgrade board)

- It has only been tested on Atari 520STM Rev.I motherboard:
https://www.exxosforum.co.uk/forum/viewt ... =53&t=2004

- The main metal shielding in your Atari will not fit unless you modify it somehow.
Maybe it's possible to get it to fit under the shielding by soldering the Blitter upgrade board directly to the motherboard instead of using a socket, and/or soldering the CPU directly to the blitter board instead of using a socket - I don't know.

Let me know if you still want one despite all those caveats :)