ACA500 plus?

[tknice]

Originally Posted by E-Penguin

Edited to add: tknice is that a Gary adapter for a trapdoor expansion bigger than 512k? Jens recommended to disable trapdoor memory >512k because of the way the memory is addressed in a way the aca500plus can't see. I assume that's still the current advice.

I have no idea. I bought the compatible 512k memory addon back in the day when I purchased this Amiga. What is a Gary adapter?

[E-Penguin]

Yes. Is your memory board one of these?
http://amiga.resource.cx/exp/adram540

Someone who knows more than I will need to weigh in here, I don't know how that would play nicely with the aca500plus / fatter Agnus chip mem thing.

[tknice]

Originally Posted by E-Penguin

Yes. Is your memory board one of these?
http://amiga.resource.cx/exp/adram540

Someone who knows more than I will need to weigh in here, I don't know how that would play nicely with the aca500plus / fatter Agnus chip mem thing.

It's the AdRAM 520. I can post a picture if it helps.

I think this one:
http://amiga.resource.cx/exp/adram520

[Schoenfeld]

Trapdoor mem expansion was limited to 512k on the A500 "back in the days". The AdRAM520 (and many similar ones) stretched this to 2MByte by adding a little logic on the Gary-chip.

I can see on tknice's picture that there is a little extra board on the Gary chip, and the cable that connects it with the actual trapdoor expansion is still there.

For proper operation with 1M Chipram, this must go. Remove the Gary-chip from the adapter, remove the adapter from the Gary-socket and plug the Gary chip directly into the Gary-socket.

Jens

[E-Penguin]

I did some experiments with a 2MB trapdoor expansion with the Gary adapter removed - it still worked as a 512kB and the aca500plus could map it as chip mem. It's worth giving it a go to save buying a new expansion.

[amigoun]

Originally Posted by Schoenfeld

Trapdoor mem expansion was limited to 512k on the A500 "back in the days". The AdRAM520 (and many similar ones) stretched this to 2MByte by adding a little logic on the Gary-chip.

Does this rule out possibility of adding more slow-ram by ACA or still possible?

[Schoenfeld]

Why do you keep on insisting on slow-ram? Are you also asking for supporting wheels on a racing cycle?

The ACA500plus has fastmem. Lots of it. There is no software that requires lots of RAM to be slow.

Jens

[amigoun]

The reason I was talking earlier was the built in AR3 which can use the slow-ram for save-state functions. That is the only but HUGE reason Thanks! I will always beg for this until it is done.
If not supported by ACA I have to keep my original setup with real AR3 hardware.

[Schoenfeld]

To solve this, hardware should not be changed. Instead, AR3 should be taught to use the memory that's there.

Jens

[amigoun]

Perfect idea! If any tests are needed with ACA or real AR3 I am ready. Thanks again.

[tknice]

Originally Posted by Schoenfeld

Trapdoor mem expansion was limited to 512k on the A500 "back in the days". The AdRAM520 (and many similar ones) stretched this to 2MByte by adding a little logic on the Gary-chip.

I can see on tknice's picture that there is a little extra board on the Gary chip, and the cable that connects it with the actual trapdoor expansion is still there.

For proper operation with 1M Chipram, this must go. Remove the Gary-chip from the adapter, remove the adapter from the Gary-socket and plug the Gary chip directly into the Gary-socket.

Jens

Gotcha. Just to clarify, will I still need the new AGNUS ECS chip to have the aca500plus map it to chip mem after resocketing the Gary chip directly in the Gary-socket?

Thought it was worth asking before I order the new AGNUS chip.

[E-Penguin]

Yes, you still need an ECS Agnus.

[mattsoft]

Hey Jens - I updated to the .89 firmware and now the ACA500+ is reliably working on my stock A1000 and A1000 with rejuvenator board in it. It boots 100% of the time. Did you do something on purpose to make it more compatible? If so, THANK YOU. If not, thanks anyways!

[Jope]

Originally Posted by brett71

To pop those chips out, I've also used a tiny flat-blade screwdriver, the kind you use to repair eyeglasses and such, put it in the little gap at two of the corners just enough to be touching the underside of the corner of the chip but instead of prying up, just turn the screwdriver about a half turn, do it at the opposite corner, and it seems to be gentle enough to pop the chip loose.

If the Agnus has never been removed, it sits there really tight and levering it gently won't do much more than scratch the corners of the chip a bit.

If the Agnus is stuck in there and you insert the screwdriver even a tiny bit too deep, you will break off the corner of the socket while you twist, and get to have a lot of fun replacing it.

This is the reason why we always say use a proper puller. Congrats to those of you who have learned this the hard way, I am not too proud to admit that I have replaced a few 84 pin PLCC sockets in Amigas (also one in an A3000T) before I got myself a proper puller.

[Zippy Zapp]

I have an ACA500 that I think is one of the greatest expansions ever made for the A500. I am tempted to upgrade to the ACA500Plus.

I know it is worth the upgrade but what is it going to give me over the ACA500 besides AR and More RAM?

[Schoenfeld]

It's not just that - expansion goes in both directions, as there's plenty of applications that require a cycle-exact 7MHz Amiga, which the ACA500plus can give you with it's "cloaking device". You can also increase the clock speed up to 42MHz, but you should NOT make that a buying decision, as there's cards that can only go 14MHz - that's the highest guaranteed frequency.

ACA500 didn't have all Kickstart versions, but the ACA500plus does have them all (except 2.0, as that's obsoleted by 3.1), even the slightly-different A1000 version. You also have the OS3.1 installation disks in flash, which makes searching/buying a set floppies unnecessary.

Floppy functions are totally new, introduced with the "plus" model: Switch off any floppy drive, or even swap df0: and df1: like the old bootselector product(s) used to do.

CF speed is much higher if you attach an A1200 accelerator, because the whole IO subsystem is 32-bit wide. This effectively doubles IO performance with a 32-bit processor. Also, even with the 68ec000 CPU, your speed is better if you run it at more than 14MHz. Further, the CF controller is completely new, eats pretty much any CF card with the selectable access speed and completely buffered signals. On the ACA500, a bad CF card could keep the whole system from starting. Oh, and hot-plug support is guaranteed on the AUX port of the ACA500plus!

Another "new" compared to the ACA500 is RTC support: You can choose the RTC to be located in one of three positions: Trapdoor, A1200 accelerator or clock port. The old model expected the RTC to be on the trapdoor expansion and didn't have any other option.

Last not least, there's compatibility with Rev.3 and Rev.5 NTSC-boards which the old ACA500 did not have.

It's just a large collection of details that I've put into this version. There's more "under the hood", so less patching of the Kickstart is required, and programming got a bit easier, but that's probably not making a buying decision. The larger flash has MMU library and the latest version of Thor's 060 library aboard, so Blizzard 040/060 boards run "out of the box" without the need to install libraries on the boot medium first (if your power supply can handle these power hungry cards).

This list is not complete - there may be even more, and other people regard other things the "killer feature".

Jens

[demolition]

I think the feature to map trapdoor mem into chip mem is also a very useful feature.

[Zippy Zapp]

@Jens,

Thank you for the info! You sold me!

The REV 5 NTSC is a big one for me and the AR access, Kickstart versions and flash, wow. My ACA500 is connected to a REV 6 but I do have a REV 5 as a backup that runs 1.2. This will be a good match.

It is nice to see all the improvements that is cool.

Thanks!

I have an aca1221ec. What would the main benefit of getting an aca1233n? I primarily want to use the machine for WHDLoad.

[demolition]

Originally Posted by Poorcomputerman

I have an aca1221ec. What would the main benefit of getting an aca1233n? I primarily want to use the machine for WHDLoad.

For WHDLoad there would hardly be any difference. The main difference is that you could use preload with very large games that require more than ~7MB memory (mostly adventure games, perhaps from 7 disks and larger) and that some 3D games like AB3D would run smoother.