New products for C64 and Amiga from Individual Computers

[moijk]

xx

[Schoenfeld]

Originally Posted by roy bates

also if it only has 2mb will there be pads on the boards for the 4mb's and couldnt i just simply add it after without sending it back?

The 2M and 4M versions have different CPLD logic, because the $c0 memory is taken from the other memory chip in case of the 4M version. This is done in order to have the largest possible *continuous* memory block - otherwise you'd have fragmented memory "by design", and that would really be a reason to complain (not just for the trolls).

So no, just soldering on the memory chip won't do the trick. It's two different logic sets, but *hopefully* the same software image for the flashrom.

Jens

[roy bates]

Originally Posted by Schoenfeld

The 2M and 4M versions have different CPLD logic, because the $c0 memory is taken from the other memory chip in case of the 4M version. This is done in order to have the largest possible *continuous* memory block - otherwise you'd have fragmented memory "by design", and that would really be a reason to complain (not just for the trolls).

So no, just soldering on the memory chip won't do the trick. It's two different logic sets, but *hopefully* the same software image for the flashrom.

Jens

ah,i see.

no worries,thanks for the answer.

[Crumb]

@Schoenfeld

Wow! nice hardware pr0n! :-)

Functionality is growing further. I even have a lab-setup that works with the B1230-IV, but that's a dirty trick that can't be used for mass production. Will continue working on that.

That sounds pretty nice. I know, no official support but hats off for trying anyway.

4MB version sounds interesting too.

[luncheon]

2MB Chip (expanded A500+ or A500 w/megachip) + 4MB of Fast RAM should be enough for most games, I think...

[cugar124]

Hi Guys
Just reading some of the Items on the ACA500 amazing Idea and what looks to be amazing specs thanks Jens.

I agree with Steve the thread is getting very hard to follow but after reading this I am going to read it again.



Al

[utri007]

I've thinked about this :/ and I need to say that product is not for me, wich makes me a bit disapointed, I really wanted one.

1. I don't want/can't to have "techmage looking" thing sitting left side of my A500. It need absolutelu have good looking cover.

2. I've I can't use any spare accelerator I have with it, then the option to add A1200 accelerator is useless. Haven't own 020/030 accelerator for 10 years and after 040/060 I don't want to have one.

Sorry to say but this is too much tinkering with details, product should be simplier, without possibility to add A1200 accelrator, it should fit inside or at least have beatifull cover.

I understand that fitting inside failed "installation by girlfriend" test, but this way it would fail "acceptance of girlfriend in public place" test. Wich is much worst :/

Keep up good working and thanks.

[Methanoid]

This thread has become pointless and filled with people going OT or moaning about good hardare. UnsubscribinG!

[Schoenfeld]

Good news for owners of an ACA1230: I just got the 42MHz version to work stable on the ACA500. I also have a 56MHz version here, but that has an overclocked 40MHz CPU that does not run stable at 56MHz. It works with ice spray, but I cannot deduct a general compatibility from that.

I didn't take the time (yet) to test the 28MHz version, but I'm confident that I can get this to work as well. Syncronous designs are now "not generally incompatible" any more. The logic can now handle a total of three different timing models that should cover all possible cases.

Jens

[Mr B]

Nice. You just keep on amazing us. Thats cool.

With the amount of tweaks and good news you keep dropping of in here, you better realize that the expectations will be high when it comes time to deliver the Indivision MKII software. Just saying. ;- )

[roy bates]

hi jens.

could you please explain a syncronous disign,do you mean cpu ,memory,or something else.or both?

i will understand if you explain fully.thanks.

[Schoenfeld]

Originally Posted by roy bates

could you please explain a syncronous disign,do you mean cpu ,memory,or something else.or both?

i will understand if you explain fully.thanks.

"explain fully" would probably take a few months, so only a few spots of the "full explanation":

Memory and CPU on an A1200 accel are always syncronous. It could be done async, but that's more complicated and would have worse performance. I doubt that there was any accelerator for the A1200 where memory and CPU were async - I don't see why anyone would spend more money and get lower performance out of the board.

"sync design" of an A1200 accel always looks at the CPU clock vs. the A1200 mainboard clock: If an accelerator does not have it's own oscillator, but derives it's clock from the A1200 mainboard, it's a syncronous design. This has the advantage of not losing any time when syncing the "fast" CPU to the motherboard for example for Chipram access. ACA1230 is a sync design.

In an async design, the accelerator has it's own clock generator which runs totally independent from the A1200 mainboard clock. This loses a little time on chipram (and other mainboard) access, but it has the advantage of freedom for the CPU and memory clock speeds.

The ACA1231 and ACA1232 are async designs: The ACA1231 benefits from maximum memory clock speed (83,325MHz), which gives the shortest-possible first-access-penalty for a fastmem access. The ACA1232 perfectly matches multiple different CPU clock speeds, which gives the highest speed that the CPU was rated for by it's vendor.

You can't say that one or the other is "the perfect approach" - both have their advantages.

Jens

[roy bates]

thank you jens.





roy.

[Schoenfeld]

More good news: I found a 68030-cpu for my "leftover ACA1230 card" that runs without cooling at 56MHz. It's stable on the ACA500 for an extended period, so I can now safely say that the ACA1230-56 will work on the ACA500.

Will test the 28MHz version in a few days - I have other things on the agenda now.

Jens

[tesla]

Hello Jens,

If I understand your explanation, synchronous is usually preferred.

But, it seems that asynchronous might be an advantage sometimes.

If so, could you design it to do either? Perhaps with a jumper or a software switch?

Hi Jens,

Just wanted to say I think the ACA500 has a lot going for it, but like many I would love to have it inside the Amiga. Would it be possible to produce/use an extension cable, so it could be internally mounted? Something like this for pci:


If it was possible & available for an extra fee I would be interested in a couple of ACA500's. I'm guessing its probably not an option & been mentioned before but I thought I would mention it just in case. I appreciate you producing something for the much neglected A500 anyway.

[Schoenfeld]

tesla:
Nope, switching between sync/async would mean changing clock frequencies on the fly. That's even more complicated and error prone. The result would be an extremely expensive design that doesn't deliver enough added performance to justify the cost.

Tpod:
No cables. Although the 86-pin CPU port is not really a high-speed bus, you can't just take the design and expect it to work on a cable, where you have signal reflections and crosstalk. Try it if you want, but don't expect any help from my side if it doesn't work.

Jens

[SpeedGeek]

A synchronous design will give the best performance when accessing motherboard resources but may not allow the CPU to run at it's optimal speed. For CPU only cards this is probably the best option.

But for accelerator cards which have fast memory (and other local resources) which are much faster than motherboard resources asynchronous is probably the better choice because it allows the CPU to run at the optimal speed for those local resources.

The number of extra wait states for an asynchronous design to access motherboard resources can be minimized by using a CPU clock speed of > 2x the motherboard clock speed.

Jens,
Thanks for letting me know.

[TjLaZer]

I don't see what the problem is with the extra $40 to get the 4MB, $40 is not very much. I would definitely get the 4MB for that extra cost!

My only concern at this point is the casing for this item. I really do not like having naked hardware hanging off the side of my A500. Reminds me of the early days when I had a Sling Shot off the side and a GVP HC+8 with 52MB SCSI HD! It was ugly but I had some extra memory and a Hard Disk on my A500 so I was content!!! Wooohoo