Open source 14MHz 68000 accelerator

[nikosidis]

Originally Posted by sovietconscript

I'm a bit late to the party here but would this accelerator work in an A2000? Also since my soldering skills are pretty much nonexistent is there anywhere to purchase one of these pre-made?

No, does not work in A2000. Only A500 and CDTV.

[hooverphonique]

Originally Posted by nikosidis

No, does not work in A2000. Only A500 and CDTV.

Why shouldn't it work in an A2000?

[nikosidis]

Originally Posted by hooverphonique

Why shouldn't it work in an A2000?

Well, it is some timing problems that for sure could be solved. What I'm saying is that the original design does not work.

[sovietconscript]

Originally Posted by nikosidis

Well, it is some timing problems that for sure could be solved. What I'm saying is that the original design does not work.

Interesting, I've always thought the A2000 was basically an A500 in a larger case with expansion slots. most accelerators and other add-ons that work with the A500 tend to work with the A2000 with no problem as are as I know.

[hooverphonique]

Originally Posted by nikosidis

Well, it is some timing problems that for sure could be solved. What I'm saying is that the original design does not work.

I see.. So in principle it should work, but due to some edge case it doesn't.

[erikarn]

Originally Posted by hooverphonique

I see.. So in principle it should work, but due to some edge case it doesn't.

yeah that's what i'm trying to figure out!

(I've put it on the back burner, will get back to it next week!)

[ItsTheSmell]

I bought one of these a few weeks back on ebay knowing nothing about this thread.


Ive installed the pins for the 68k socket the wrong way around, do I need to correct this?


I have the standard accelerator card (rev 2.2) is this the latest version? Do I need to correct anything before proceeding?

[Mathesar]

Originally Posted by ItsTheSmell

I bought one of these a few weeks back on ebay knowing nothing about this thread.


Ive installed the pins for the 68k socket the wrong way around, do I need to correct this?


I have the standard accelerator card (rev 2.2) is this the latest version? Do I need to correct anything before proceeding?

Yes, rev 2.2 is the latest version, you won't have to patch anything.
What do you mean exactly by pins the wrong way around? Did you solder the thin pins on the accelerator board? (so that the thicker pins stick out and go jnto the motherboard?)

[Mathesar]

Originally Posted by erikarn

here's some traces during autoconfig in diagrom! all done in pulseview.

Did you ever got furher with this? I was looking at your trace captures again and I saw one weird thing: All your traces are read cycles as R/_W is high. If i understand correctly, buster should set d2p high then to setup the bus buffers for a read operation (D2P = data to processor). However, in your first trace d2p is set low on the first read operation. The cpu will then definately read garbage explaining that autoconfig will fail.

What do you think?

[ItsTheSmell]

Hi Mathesar, yes thats how i installed the pins, i thoight the fatter ones would fit better in the 68k socket; making a better contact.

[Mathesar]

Originally Posted by ItsTheSmell

Hi Mathesar, yes thats how i installed the pins, i thoight the fatter ones would fit better in the 68k socket; making a better contact.

I see. The fatter pins can damage your socket and are not meant to put in a socket. Have you already soldered them down? I think it is very hard to desolder and correct it.

[ItsTheSmell]

I have soldered them down mate, yes. To my eyes they looked the same size but one side had a fatter top, for better contact with the socket. Ill have to redo it. Can the emf shielding be placed back on when the accelerator is fitted?

[Mathesar]

Originally Posted by ItsTheSmell

ICan the emf shielding be placed back on when the accelerator is fitted?

Yes.

[ItsTheSmell]

So last night i tried to unsolder the pins from the board and i can confirm its a PITA.

Can i buy a new pcb, pins and cpu socket from someone?

I have an A500+ so will this accelerator work?

[Mathesar]

Originally Posted by ItsTheSmell

So last night i tried to unsolder the pins from the board and i can confirm its a PITA.

Can i buy a new pcb, pins and cpu socket from someone?

I have an A500+ so will this accelerator work?

I have searched but unfortunately but I have no bare boards left .
The accelerator should work just fine in an A500+. The only known incompatibilities are with DMA sidecars like the A590 and, apparently, Amiga 2000 Zorro-II devices.

[ItsTheSmell]

Hmmm, i have a Supa 500xp sidecar with 8mb ram, is this incompatible?

Ive sourced a new board from the ebay seller.

[Mathesar]

Originally Posted by ItsTheSmell

Hmmm, i have a Supa 500xp sidecar with 8mb ram, is this incompatible?

Ive sourced a new board from the ebay seller.

Yes, it's incompatible

[Mathesar]

Why don't you try the "SE" version?
https://github.com/Mathesar/14mhz-accelerator-SE
I have designed it to be compatible with the A590 and Supra sidecars. It contains no memory but as you already have 8MB of fast ram anyway it won't make much of a difference.

[TheGouldFish]

I built the SE version this week for my A500+ with a GVP HD8+

and SysInfo reports it running at 12.50 and says its a little bit faster.
I've gotten some games to run on it, like the WHDLoad version of Ruff N Tumble.

but when I played Operation Stealth it crashes quite quickly.

[Mathesar]

Hi GouldFish!

First things first: You are the first that I know of that has built the "SE" version.
Can you confirm that it works indeed with the DMA SCSI controller of the GVP HD8+?
That would be good to know because that is what this version was supposed to do.
As for the crashing in Operation Stealth, it could be that your 68000 does not like to be overclocked so well. You could try to source a (faster) HC part.

But congratulations on your build. Looking good