ACA500 plus?

[amigoun]

Yes, you are right, there possibly isnt any software requiring larger slow-mem block.
But main reason for me is that Action Replay 3 only can use the slow-ram as a buffer for its quick save-states.
Now when memory limiting F3 functions is fixed (thanks for that fix!) I can use the built-in AR to quick-save the state of 512kb games. If larger block of slow-ram is available it would be possible to use quick save for 1MB games too.
Just like I did and still do on my old setup where I have 1,8 slow ram expansion (with gary adapter) and thus have enough buffer to quick save 1mb games with AR3.

[appiah4]

That.. actually makes sense. Maybe HRTMon can do it with FastMem?

[amigoun]

HRTMon can not save to RAM, but can save to HDD if compiled with ide switch. But problem with HRTMon and games is that upon exiting HRTMon graphics corruption in games may appear. So for playing games purpose AR3 is better choice.

[tknice]

Hey Guys,

Loving the ACA500+ so far! I have a stupid question for you...

I'm working with an A500 with 512 of trap door ram and noticed that a few of the games I try to run give me the message, "You need chipmem up to $100000 (1024 KBytes) to run this program."

I'm guessing this is referring to the 1MB ram I see in my ACA500 config that is unavailable? Does my system ram + trap door not total 1MB? Is there any way to allocate some of the 8MB the ACA500+ has for this purpose?

Thanks so much!

Edit: Forgot to mention I flashed the latest V0.89 firmware.

TK

[mattsoft]

The ACA500+ only adds fast RAM. Your trapdoor RAM expansion might not be adding to your A500's chip RAM. Remove the ACA500 and boot your A500. What does the workbench say for RAM? If it says you have .5MB graphics (chip) and .5MB fast, then your trapdoor RAM is not chip. You may need to get a different type of RAM expansion in there.

[tknice]

Originally Posted by mattsoft

The ACA500+ only adds fast RAM. Your trapdoor RAM expansion might not be adding to your A500's chip RAM. Remove the ACA500 and boot your A500. What does the workbench say for RAM? If it says you have .5MB graphics (chip) and .5MB fast, then your trapdoor RAM is not chip. You may need to get a different type of RAM expansion in there.

Thanks Mattsoft. Unfortunately, I can't boot without attaching the ACA500 because my floppy is dead and/or my 1.2 workbench disk is unreadable. Possibly both.

On a side note, where is this system info screen I see everyone referring to? I can't find it anywhere in workbench.

[Toni Wilen]

1M Chip RAM option requires ECS Agnus (8372A). Check what TAB info screen says.

[tknice]

Originally Posted by Toni Wilen

1M Chip RAM option requires ECS Agnus (8372A). Check what TAB info screen says.

Looks like I have OCS Agnus. So out of luck then on these games?

[mattsoft]

yup, you need the ECS agnus and from what I recall, you can't simply replace the agnus chip alone. if you want 1 MB (or higher) chip RAM, you could find a later revision A500 MB and swap, get an A500+ (or just the MB and swap), or get on the list for a Vampire card.

[demolition]

I think ECS Agnus is pin compatible with the OCS ones, so simply replacing it should work. What you can't do it replace a 512k/1M Agnus with a 2M version, but he's not asking for that. With the right Agnus, the ACA500plus should be able to remap the 512k in the trapdoor into chip, no matter what kind of mem expansion is in there.

Also, getting a Vampire won't help with the issue of missing chip mem. Even if he added a Vampire (which is probably way overkill for most people), he would still be left with 512k chip since the Vampire won't (and can't) provide any additional chip mem.

[E-Penguin]

I've got a spare ECS Agnus, PM me if you want it.

On the subject of memory though, I'm not convinced I'm getting as much "other" mem as I should be. I see around 6.7 available when I start workbench 3.1 with maprom.

[tknice]

Originally Posted by demolition

I think ECS Agnus is pin compatible with the OCS ones, so simply replacing it should work. What you can't do it replace a 512k/1M Agnus with a 2M version, but he's not asking for that. With the right Agnus, the ACA500plus should be able to remap the 512k in the trapdoor into chip, no matter what kind of mem expansion is in there.

Also, getting a Vampire won't help with the issue of missing chip mem. Even if he added a Vampire (which is probably way overkill for most people), he would still be left with 512k chip since the Vampire won't (and can't) provide any additional chip mem.

Thanks for the info, demolition.

Do you know if I need to do anything else other than replacing the Agnus chip with an ECS version to get this working?

I believe my A500 motherboard is a rev5.

[demolition]

Originally Posted by E-Penguin

On the subject of memory though, I'm not convinced I'm getting as much "other" mem as I should be. I see around 6.7 available when I start workbench 3.1 with maprom.

I also have around 6.7MB so that sounds right. I think Maprom will consume 512k so you should have a total of 7.5MB fast.

Originally Posted by tknice

Do you know if I need to do anything else other than replacing the Agnus chip with an ECS version to get this working?

Not sure if Rev. 5 have all address pins mapped out or if some are missing. If it does have all connections, then it should work.

[Schoenfeld]

Rev.5 is fine for those in NTSC-land, as there is only one difference between the OCS and the ECS Agnus pinout: The "Test" pin of the OCS chip turned into a "PAL/NTSC switch" pin on the ECS version.

Since "test" is grounded on Rev.5, the ECS Agnus will be put into NTSC mode when dropped in, so perfect for tknice, who is from the US.

The chip alone won't give you 1MByte chipram, but the ACA500plus can do the rest. While you'd have to do some trace scratching and soldering without the ACA500plus, you just activate the ChipMap feature in the ACA500plus menu, and all address lines to the Agnus chip will be toggled the right way.

Ignore all other instructions, such as "switch off the internal RAM expansion" - that's only true if you don't have the ACA500plus. If you're unsure, make the system work without the ACA500plus in 512k+512k configuration first. When that works with the ECS Agnus, don't change anything, just plug in the ACA500plus and let it do it's thing.

Jens

Edit: don't cheap out on the chip-puller tool. Yes, there are 5-dollar-tools available, but they only destroy the chip. Better go for the 20-dollar variant.

[tknice]

Originally Posted by Schoenfeld

Rev.5 is fine for those in NTSC-land, as there is only one difference between the OCS and the ECS Agnus pinout: The "Test" pin of the OCS chip turned into a "PAL/NTSC switch" pin on the ECS version.

Since "test" is grounded on Rev.5, the ECS Agnus will be put into NTSC mode when dropped in, so perfect for tknice, who is from the US.

The chip alone won't give you 1MByte chipram, but the ACA500plus can do the rest. While you'd have to do some trace scratching and soldering without the ACA500plus, you just activate the ChipMap feature in the ACA500plus menu, and all address lines to the Agnus chip will be toggled the right way.

Ignore all other instructions, such as "switch off the internal RAM expansion" - that's only true if you don't have the ACA500plus. If you're unsure, make the system work without the ACA500plus in 512k+512k configuration first. When that works with the ECS Agnus, don't change anything, just plug in the ACA500plus and let it do it's thing.

Jens

Edit: don't cheap out on the chip-puller tool. Yes, there are 5-dollar-tools available, but they only destroy the chip. Better go for the 20-dollar variant.

That great Jens! I read about all the trace scratching and other stuff in some post from years ago and it made me really nervous. I don't want to mess my original A500 up, just to play a few extra games.

So I may try this then. Unfortunately for me, E-Penguin's chip is a PAL version and I'm here in the states and probably need NTSC? I just ordered an RGB>Scart cable and Scart>HDMI 720/1080p upcaler to work with a flatscreen. Do you think this would make a difference with the type of AGNUS chip I get? If it won't work, I can hunt for an NTSC ECS chip.

EDIT: I read your post again and it sounds like his PAL version will switch to NTSC for me. Is that correct?

Thanks for all of the info guys--and Jens, you have really outdone yourself with this board! I've really enjoyed playing Defender of the Crown, Great Giana Sisters and all these other memorable games on my old setup! So Cool!

I'll get the right chip puller for this as well. If you have any other advice on switching out the AGNUS or anything else I need to check first, I'd love to hear it.

Thanks,

TK

[Schoenfeld]

Originally Posted by tknice

So I may try this then. Unfortunately for me, E-Penguin's chip is a PAL version

I doubt that. The 8372a is switchable between PAL and NTSC, and if you just drop it into a Rev.5, it will come up in NTSC mode. It still allows software to switch between PAL and NTSC (one of the enhancements of the enhanced chip set ECS).

I've mentioned here in this thread that I have a few very rare 8375 chips that have the 8372a pinout, but the PAL/NTSC pin with a completely different function. These are really available in two different startup-modes PAL and NTSC, and I only have the PAL version. However, these are so extremely rare that hardly anyone knows about them. I'm sure that you've been offered a 8372a chip - Vesalia has them for 6.90 EUR each incl. VAT, so even less for those outside the EU.

Originally Posted by tknice

If you guys have any other advice on switching out the AGNUS or anything else I need to check first, I'd love to hear it.

If a chip puller is not available, you can also remove the board from the case completely (loosen all the bolts of all connectors at the back) and push the chip out through the two holes in the board. These holes line up with holes in the socket, so you can reach to the chip from the bottom side of the board with a screw driver. Be careful - you'll be surprised about how much force you need to apply!

Jens

[tknice]

Originally Posted by Schoenfeld

Vesalia has them for 6.90 EUR each incl. VAT, so even less for those outside the EU.

Thanks Jens. Is this the one I'm looking for on Vesalia's page:

IC 8372A (318069-02), 1 MB Agnus for A500/A2000 (PAL and NTSC)

It's the square chip in the middle, correct?
Here's a pic of my board:
https://dl.dropboxusercontent.com/u/...9-11h42m17.JPG

And the other side of the board where I see the Rev 5.
https://dl.dropboxusercontent.com/u/...9-11h41m27.JPG

Do you happen to have a link to a nicer $20 chip puller you recommended for removing it? I can definitely remove the board and pop it out from behind if you think that is safer.

[idrougge]

Do it from behind. As long as you apply equal force, it is safer.

[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.

Now I'll probably get a flood of people saying "No! No! NO! That's wrong!" hehehehe

[E-Penguin]

No! No! NO! That's wrong!

I got the cheapest plcc extractor I could find on ebay and that works fine, not a scratch on the old chip. Your mileage may vary, obviously. I wasn't sure which versions of Agnus are PAL/NTSC - the one in the MegAChip is PAL only though? I can't remember the part number offhand.

tknice I paid twice what Vesalia's asking, seems a bargain. Go for it.

Jens I did the trace scratching thing when I installed the MegAChip, but I'm not entirely confident I did a good job on the one by the trapdoor. Everything seems to work but can you (or, indeed, anyone else) recommend a good memory check tool? The ACA500plus recognises it as 2MB chip

----
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.