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RAM 320XL

ctirad

By ctirad
in Atari 8-Bit Computers

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200 members have voted

  1. 1. I'm interested in:

    • RAM 320XL naked version
      30
    • RAM 320XL full version
      125
    • RAM 320XE
      60
    • RAM 576+
      63
  • Please sign in to vote in this poll.

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flashjazzcat Quadrunner

flashjazzcat

Posted
Posted

Well come on: let's have a definitive explanation. I have someone here waiting for his 600XL back and he wants to know how much memory the damn thing has in it. I can get it running with a jumperless 320XL module. XRAM detects 256KB and all is well. It won't boot with the jumper in place. Saying that "some people don't understand" is of no help whatsoever.

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ctirad Moonsweeper

ctirad

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Except in those cases where the jumper is removed and the base RAM is switched out. :)

 

Wrong! The onboard RAM is switched out when the jumper is CONNECTED, BUT the additional 64kB of RAM is mapped to its place. From a software point of view there is no difference. The only difference is that the base 64kB memory is not located in the original onboard DRAM chips, but inside the RAM 320XL SRAM chip above the 256kB space (the RAM 320XL uses the 512kB SRAM chip, BTW ). Is it clear now?

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ctirad Moonsweeper

ctirad

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I can get it running with a jumperless 320XL module. XRAM detects 256KB and all is well.

 

 

XRAM detects and tests just the extended memory, which is allways 256kB in the RAM320XL case. Total memory is 64kB + extended memory. It means the 130XE has 64kB of extended memory (128kB total), RAM 320XL has 256kB of extended memory (320kB total), half meg RAMBO/COMPY has 512kB of extended memory (576kB total) and finally one meg extensions has 1024kB of extended memory (1088kB total).

 

Yes I know there exits also a 192kB extension which gives 256kB of total memory, but this extension is very uncompatible because it cannot be correctly autodetected (please correct me Fandal if I'm wrong ).

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Rybags Quadrunner

Rybags

Posted
Posted

So with the jumper removed, the base 64K is mapped to the lower 256K bank on the RAM320XL board, instead of onto the higher bank? It was previously NOT clear to me that in both cases the computer's base RAM was switched out.

 

Jumper removed = don't overlay any main RAM, only map in extended banks if selected by appropriate PORTB setting.

 

That's needed otherwise VBXE won't work.

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Guitarman Stargunner

+Guitarman

Posted
Posted

I think the easy explanation is:

 

320XL: uses a chip capable of 512K total. Only a portion is used in the upgrade.

 

Jumper On: Internal ram not used. All 320K (64K base and 256K extended) is mapped to the 320XL upgrade. Good for bypassing bad internal ram.

 

Jumper Off: Internal ram used as base ram (16K for unmodded 600XL and 64K for 800XL or modded 600XL). 320XL used as extended ram only (using only 256K for extended). This should mean that on a 16K 600XL with the jumper removed, you will have a total of 272K (16K base and 256K ext). I think he is saying that this mode is only there for VBXE systems that need to have the base memory internally active to work.

 

XRAM: XRAM tests extended ram only, so will always show 256K regardless of the jumper setting.

 

Let me know if I'm off on this.

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ctirad Moonsweeper

ctirad

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Sounds right to me.

 

Yes, it is exactly as Guitarman said.

 

Question I have though... couldn't we have had an "Option 3" where internal RAM is enabled, and all the external RAM is mapped via PORTB, giving 64K internal + 512K external ?

 

It is possible with a small modification of atari (need to cut one track and to solder one wire) and a custom firmware.

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Wilheim Dragonstomper

Wilheim

Posted
Posted

Pffff... I just dismantled, jumpered it off, and boot OK. Then I jumpered it on again, and it worked!!!

 

Don't ask me what happened. I don't know.

 

It really rocks!!!!!

 

One more thing: I can't put the power piglet and the SIO cable at the same time. Looks like I have to connect the +5V into the PBI of my 800XL.

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Wilheim Dragonstomper

Wilheim

Posted
Posted

Then again, I answered myself: The PBI connector is in a different place in the 800XL rather than the 600XL.

 

I tested in my 600XL (NTSC Rev. A Board) and my 800XL, and all of them worked fine. I even replaced the ANTIC chip with a PAL one, so I could use it with many european demos. They all worked fine until now. Numen rocks in the real thing!

 

Regards.

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Defender II Stargunner

Defender II

Posted
Posted

Then again, I answered myself: The PBI connector is in a different place in the 800XL rather than the 600XL.

 

I tested in my 600XL (NTSC Rev. A Board) and my 800XL, and all of them worked fine. I even replaced the ANTIC chip with a PAL one, so I could use it with many european demos. They all worked fine until now. Numen rocks in the real thing!

 

Regards.

 

They all worked fine until now.

Did you mean to say... 'They all work fine now.'? Using 'until now' sounds like they no longer work...

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Defender II Stargunner

Defender II

Posted
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Well, I just received today the 3 boards, and tested them with a NTSC 600XL. Two of them work fine (tested with cartridges using 64k and XRAM for the extended banks), but the third one doesn't seem to work. The 600XL doesn't even boot.

 

What could it be? Any suggestions?

 

I had similar problems with mine. The first one worked right away but the next needed to be removed and then plugged back on to the PBI. I think if the RAM 320XL is plugged in too far left or right you get problems. I only checked mine on an 800XL so far with the pig tails, but really bought these for my 600XL. I love the small footprint on the 600XL and the Ram 320XL!!!!! I got the bare and black case RAM 320XL, but saw someone had a blue cased one. I'd like to get two of those blue cases if I can.

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Kernal Moonsweeper

Kernal

Posted
Posted

Ill be paying for mine tonight.. i had a couple of paypal problems that have been resolved.

 

Ok so Paypal says its gonna be monday when its in there... i started the transfer from my bank to pay pal on monday... and here it is saturday and its still not in there.. what a bunch of slow bunnies.

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Almost Rice River Patroller

Almost Rice

Posted
Posted (edited)

I got my PAL 16k 600xl to work. I got it from reading Mathy's web site. In the page he refers to Bob Puff's article STABILIZING XL/XE COMPUTERS WITH PBI DEVICES After reading it, I figure adding the connection between pin 1 to pin 4 on 74ls08 was what I needed.

 

Here is a pic of the fix. Its the small DIP on the bottom left.

post-7833-128202186367_thumb.jpg

BTW the 600xl MB is a Rev B.

Edited by Almost Rice
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ctirad Moonsweeper

ctirad

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That's AWESOME!!! Thank you very much Almost Rice for this find. Now it's clear that there is really something wrong with some ataris and it it is related to a particular CPU fitted rather than a revision of the motherboard.

 

I hope this will work for the other "bad" XLs.

In meantime I prepared an alternative firmware with slightly modified timing, but it looks it won't be necessary.

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