Open source 14MHz 68000 accelerator

[Santi]

I have tested it on an a500 rev6. I turned on the computer and it showed the floppy disk of the rom 1.3.<br />
Hallelujah. I wanted to try some software and I connected the hd supra, with 2mb of ram. It did not start and the screen is black.<br />
I have read that there may be problems with rams and hd's. I can assume it and use it for gaming with the gotek, and not hd.<br />
When I remove the hd and ram, and connect it again by itself, wb 1.3 image no longer appears<br />
Ah, I have tried with an a2000 and a cpu relocator (1mb ram chip and without any expansion), rev 4.5 and it doesn't work either. black screen.<br />
Has anyone tried mobo rev6?<br />
I had a really hard time getting the pins into the mc68k socket. Perhaps by touching with my hands, you have distilled some ic by static electricity.<br />
I think I will have to change the ic logic.

[Glen M]

I recently got one of these cards but before I go testing it are there any pitfalls to watch for?

Flicking through the various comments here am I correct in saying that this accelerator makes trap door memory redundant?

Can I ask out of interest if the 14mhz clock generated on the card or is it taking the 7mhz clock and doubling it? If the 14mhz clock is on the card is there any reason to limit it to 14mhz, could it go faster?

[keithamiga1200]

Originally Posted by Glen M

I recently got one of these cards but before I go testing it are there any pitfalls to watch for?

Flicking through the various comments here am I correct in saying that this accelerator makes trap door memory redundant?

Can't answer your last paragraph, but I assembled mines the other day, and it's 'Alive' I don't have an external HDD to test, but apparently it's not compatible. Which kinda makes sense, considering all the HDD and extended memory magic, is done by the actual external HDD unit.

[Samurai_Crow]

The 14 MHz signal is from a clock doubler. It's not independent of the 7 MHz clock and would require a redesign to go faster.

[Mathesar]

The problem is not so much with HD's but with DMA capable HD controllers. Currently the accelerator does not support DMA controllers at all. It could be fixed in an updated revision but currently I do not have much time.
If there is a way to disable DMA on the supra it should work.

Originally Posted by Santi

I have tested it on an a500 rev6. I turned on the computer and it showed the floppy disk of the rom 1.3.<br />
Hallelujah. I wanted to try some software and I connected the hd supra, with 2mb of ram. It did not start and the screen is black.<br />
I have read that there may be problems with rams and hd's. I can assume it and use it for gaming with the gotek, and not hd.<br />
When I remove the hd and ram, and connect it again by itself, wb 1.3 image no longer appears<br />
Ah, I have tried with an a2000 and a cpu relocator (1mb ram chip and without any expansion), rev 4.5 and it doesn't work either. black screen.<br />
Has anyone tried mobo rev6?<br />
I had a really hard time getting the pins into the mc68k socket. Perhaps by touching with my hands, you have distilled some ic by static electricity.<br />
I think I will have to change the ic logic.

[Mathesar]

Originally Posted by keithamiga1200

Can't answer your last paragraph, but I assembled mines the other day, and it's 'Alive' I don't have an external HDD to test, but apparently it's not compatible. Which kinda makes sense, considering all the HDD and extended memory magic, is done by the actual external HDD unit.

Congratulations with your build Pictures or it did 't happen
For an HDD on the cheap to go with the accelerator, what about one of those SD to parallel boxes?

[hooverphonique]

Originally Posted by Glen M

Flicking through the various comments here am I correct in saying that this accelerator makes trap door memory redundant?

If you want trapdoor memory space available when the accelerator is "off", you need to keep your trapdoor memory - when "off", it simply disables the on-board fastram.

[Bruce Abbott]

Originally Posted by Mathesar

Congratulations with your build Pictures or it did 't happen
For an HDD on the cheap to go with the accelerator, what about one of those SD to parallel boxes?

Need to combine this design with an IDE controller, then add a Kickstart ROM socket or onboard Flash ROM to run the OS at full speed and it will be perfect!

[Santi]

I think this is a fantastic project. Anything that is to study and improve, or expanding our dear Amiga, it is commendable and thanks to its creator. Doubling the speed of an a500 is already noticeable, as long as it is with applications. I doubt very much that it is noticeable in performance with games, basically because the programs will have synchronization routines so the real clock will not affect them.
Therefore, making it compatible with hard drives I think is very necessary. And maybe expandable to at least 4mb on the same board.
And it's great for the idea, and for the price / cost of making one.
Any other implementation would make it more expensive ... like other existing solutions already on the market.
My sincerest congratulations.

... On the other hand ... I haven't gotten mine to work. I suspect that the 68000 socket is defective and does not make good contact with the throttle pins. It worked for me in several starts. After no longer any of the repeated attempts. I think I will unsolder all ICs and exchange them for new ones. It is the good thing about it, how cheap it is to manufacture.<br />

I hope, more people who try it and leave their comments and opinions here in this thread.

[PeteAU]

That's a cute board, might have to build one! Those PLCC 68000's are pretty speedy aren't they?

[Mathesar]

Originally Posted by PeteAU

That's a cute board, might have to build one! Those PLCC 68000's are pretty speedy aren't they?

Yes, they can be overclocked quite a bit. Up to 50MHz sometimes.
But in this design it won't go faster than 14MHz.

[nikosidis]

Card is fantastic.
Made a little video playing Dread.
You will see standard A500 and with the accelerator.

[ Show youtube player ]

[Mathesar]

Originally Posted by nikosidis

Card is fantastic.
Made a little video playing Dread.
You will see standard A500 and with the accelerator.

[ Show youtube player ]

Nice video! Dread runs nice on it doesn't it? I'm glad you like it!

[Mathesar]

Originally Posted by Santi

... On the other hand ... I haven't gotten mine to work. I suspect that the 68000 socket is defective and does not make good contact with the throttle pins. It worked for me in several starts. After no longer any of the repeated attempts. I think I will unsolder all ICs and exchange them for new ones. It is the good thing about it, how cheap it is to manufacture.<br />

I hope, more people who try it and leave their comments and opinions here in this thread.

I am sorry to hear that yours is not working anymore. Can you check the voltage on the 14MHz test point? It should read in the neighbourhood of 2.5V. Maybe your card has a problem with the clock doubler causing erratic behaviour. Also, if you do try to replace components, start with replacing U5 and then check again. U5 drives ~AS7 and when you connect the Supra, the two might conflict and potentially damage U5.

[nikosidis]

Originally Posted by Mathesar

Nice video! Dread runs nice on it doesn't it? I'm glad you like it!

Dread runs very nice Thanks for the design.

I'm very happy with the card. Everything I'm trying just work.

I had one problem. That is at the end of the demo "EON"

That was solved with CTRL + Amiga + Amiga some sec. to disable the fast ram

Also Tinyus run perfect!! That game is sluggish on plain A500.

[nikosidis]

I made another video about some benefits I found using the card

[ Show youtube player ]

[nikosidis]

I made another video about some benefits I found using the card.

[ Show youtube player ]

[utri007]

I got a board few days a ago and it works just fine and with hw compo I planned.

I have a GVP HD8+ SCSI / Ram expansion and KCS Power PC emulator board.

How ever, GVP's ram priority is 0, this board ram's priority is -5. Any advises how to change this? Other than these three form aminet http://aminet.net/search?query=memory+priority

[Jope]

Your best way really is to try the tools you found.

[utri007]

Originally Posted by utri007

I got a board few days a ago and it works just fine and with hw compo I planned.

I have a GVP HD8+ SCSI / Ram expansion and KCS Power PC emulator board.

How ever, GVP's ram priority is 0, this board ram's priority is -5. Any advises how to change this? Other than these three form aminet http://aminet.net/search?query=memory+priority

It seems to have a problems with DMA and SCSI.

If I change accelerators ram priority to higher than Zorro II ram, hard drive access locks computer.

OK, options are :

make sure that SCSI doesn't try DMA to accelerator's memory?? How?
change GVP to use PIO? How?