1064 replacement possible?

[Mathy]

Hello guys

 

As most of us know, you need 64kB of main memory for most memory extensions.  But some of us are reluctant to open up the 600XL to replace the two 16k RAM chips with two 64k RAM chips.  And the 1064 are hard to come by sometimes.

 

That's when the following idea popped into my mind:

 

Would it be possible to design/realize a 1064 replacement, using modern hardware to make the device smaller, that could also be used with any external expansion that requires 64kB of main memory?  With this redesigned 1064, the 600XL should look like an 800XL to all devices connected to it (via whatever port/bus) and should be able to handle every piece of hardware the 800XL can handle, without any restrictions the 800XL doesn't have.

 

Sincerely

 

Mathy

 

PS as always, this is just an idea.  If you like it, please realize it.  I'm not able to.  I just come up with the (dumb) ideas.

 

 

[+Philsan]

I know someone is working on it.

[+Larry]

I never tried it with a 600XL, but couldn't the RAM 320XL memory expansion be used in this way?  The only thing it lacked was a pass-thru for the pbi. That would seem to be a really good starting point for a new & improved 1064.

[tjlazer]

The first thing I did when I got a 600XL was do the 64k mod, it's so easy it's a no brainer!  16k is just not enough for an XL computer.  Just do it.

[+bob1200xl]

Wouldn't a 1064 do what you need? Are there problems with just using a 1064?

 

I am guessing that the 1064 just kills the 16K chips and slides in 64K.

 

Bob

 

[+Larry]

Hi Bob-

Where would one get a 1064?  The supply seems to have dried up some time ago.

-Larry

[+Allan]

58 minutes ago, Larry said:

Hi Bob-

Where would one get a 1064?  The supply seems to have dried up some time ago.

-Larry

Waiting for Bob to say "Well, I got a whole shed full of them! Doesn't everybody have a stock pile of these?"

[+bob1200xl]

Me?

 

I have two in my Computer Room. Other than those, I would have to search my Atari Barn (shed? pleeze... my shed is where I park my John Deere!)

 

I would expect that we would make new 1064s if we were making a project around them.

 

Bob

 

[+mytek]

Well if all you want is an external 600XL RAM expansion with no soldering or disassembly required, then I think a remake should take it up to 512K or more without requiring the internal 64K mod. Why bother remaking a 64K upgrade at this point in time, when large SRAM chips are cheap and readily available.

[+x=usr(1536)]

4 hours ago, Larry said:

Where would one get a 1064?  The supply seems to have dried up some time ago.

That's the key - they're not easy to come by these days.  I know how long it took for me to find mine, and required buying the 600XL it was attached to in order to obtain it.  While I didn't mind having to take the 600XL along with it (I had been looking for another one for a while), it did push me towards doing an internal 64K upgrade on the first machine for the sake of expediency.

7 minutes ago, mytek said:

Well if all you want is an external 600XL RAM expansion with no soldering or disassembly required, then I think a remake should take it up to 512K or more without requiring the internal 64K mod. Why bother remaking a 64K upgrade at this point in time, when large SRAM chips are cheap and readily available.

Agreed.  I have zero regrets about doing the internal 64K mod, but can't come up with a good reason as to why an external upgrade (which really means PBI-attached in this case) should top out at the same number.

 

@candle's external version of the U1MB, when released, will pretty much fulfill the role of a 1064 replacement and then some.

[+Larry]

After a little digging here at AA, I found the answer about the RAM 320XL:

 

It would still be nice to have someone verify that it worked properly in the 600XL.  BTW, it made a big difference in the AA search if I typed this a RAM 320XL or RAM320 XL (etc.)  12 results versus 253.  I had a couple of these, but sold them because of the lack OF PBI pass-thru.

 

I still think this is the place to start for a repro.  It will not be close to an External U1MB in terms of features, but offers a lot for 600XL owners.

 

 

[Peri Noid]

It works properly on an unexpanded 600XL. I tried. The only thing is, you have 256KB of expanded RAM (bank switched, Rambo style) but still only 16KB of basic RAM. Expanded RAM doesn't help here at all.

 

By the way - there is a solution. You need SysCheck 2.2 (XL or universal). Among its features, it has on-board 64K which can substitute the board RAM.

Edited June 14, 2021 by Peri Noid

[+Larry]

See the posts starting around #200 and up in Ctirad's thread.  Evidently the RAM 320XL didn't work properly with some 600XLs. Too bad.

[ivop]

11 hours ago, mytek said:

Why bother remaking a 64K upgrade at this point in time, when large SRAM chips are cheap and readily available.

Maybe cost? A small board with a 64kB SRAM chip and one 74xx chip would suffice to replace the 1064. Either by only responding to $4000 and up, or perhaps use the syscheck trick to replace the internal RAM.

 

[+mytek]

37 minutes ago, ivop said:

Maybe cost? A small board with a 64kB SRAM chip and one 74xx chip would suffice to replace the 1064. Either by only responding to $4000 and up, or perhaps use the syscheck trick to replace the internal RAM.

Agreed, except it would only be a few dollars more to make it at least equivalent to a 130XE. And unless this is planned as an ultra cheap naked PCB only offering, by the time you create a 3D printed case, you may as well put it on equal footing with a 130XE, or take it up to 320K for even broader compatibility with the newer offerings. It would require an EMMU to expand beyond the onboard 16K without leaving any holes in the memory map, but I'd be surprised if someone hasn't already coded a GAL or CPLD to do that.

[ivop]

15 minutes ago, mytek said:

Agreed, except it would only be a few dollars more to make it at least equivalent to a 130XE. And unless this is planned as an ultra cheap naked PCB only offering, by the time you create a 3D printed case, you may as well put it on equal footing with a 130XE, or take it up to 320K for even broader compatibility with the newer offerings. It would require an EMMU to expand beyond the onboard 16K without leaving any holes in the memory map, but I'd be surprised if someone hasn't already coded a GAL or CPLD to do that.

Also agreed If it were a product to be sold, a few dollars more wouldn't be the problem, and neither would be programming a GAL/CPLD.

 

But for an open source DIY project, a GAL or CPLD could be a problem for some people.

 

[+mytek]

18 minutes ago, ivop said:

Also agreed If it were a product to be sold, a few dollars more wouldn't be the problem, and neither would be programming a GAL/CPLD.

 

But for an open source DIY project, a GAL or CPLD could be a problem for some people.

Understood , but I don't think Mathy's request limited this to a DIY device only. So my take on it is definitely leaning towards a product offering by one of our many Atari upgrade dealers.

[Marius]

2 things:

1. The idea is pretty cool, both the idea of simply 64K and the idea of 512K. I am probably the only fool in this scene, but I still like the idea that my Atari is simply loaded with 64K and nothing more. 

2. The 1bit DRAMS are pretty easy to obtain (if I am correct) ... I also stacked 2x four of them in my 64K upgrades in stead of 2x 4bit. Worked excellent. So if people still want the 64K internal, but they can not get the 4bit DRAMS, they could do to the trick with the stacks. I will have to think about how they are connected. You have to cut some legs. It has ben over 15 years since the last time I did that. 

[Mathy]

Hello guys

 

Hmm, I guess most of you are not getting my point.  Let me try to explain some more:

 

- Not everybody wants to open their 600XL to upgrade it to 64kB of main RAM.  And some of us aren't able to upgrade the 600XL to 64kB.  And for some reason don't want to send it to someone who does.

- The 1064 is hard to come by.  And size wise it's probably as small as they could have made it way back when.  A new replacement could be much smaller.

- There are plenty of devices that can act as an external memory upgrade.  Some even let you configure them as main RAM.  But can they provide 64kB of main Ram and at the same time offer the rest of the available RAM as a RAM expansion?

- Memory expansions ($D301, Axlon, etc.) and only 16kB of main RAM often just isn't gonna cut it.

 

What I would like to see is a small 1064 replacement.  That plugs into the 600XL to get 64kB of main RAM.  And since the small 1064 replacement would have a PBI passthrough, you could plug an existing external memory expansion into the small 1064 replacement and you'd have an XL with 64kB of main memory and what ever amount of expanded memory ($D301, Axlon, etc.).  Plus you would not need different versions of an external memory upgrade ($D301, Axlon, etc.) for the 600XL and the 800XL.  It's cheaper to build a small 1064 replacement that can be used with any external memory expansion ($D301, Axlon, etc.) plus an external memory expansion ($D301, Axlon, etc.) than it is to build two different external memory expansions ($D301, Axlon, etc.), one for the 600XL and one for the rest.

 

Sincerely

 

Mathy

 

[+mytek]

I retract my suggestion of having it be an expanded version that would not only increase the base RAM from 16K up to 64K, but also add additional banked RAM as well. All without having to do any internal mods or soldering. I just thought that would be even better then to simply remake the original 1064, but I obviously misunderstood the OP in this case. So now I'll sit back, grab some popcorn, and wait for the stampede of makers that will bring that into reality

 

BTW, I totally get where the OP was coming from, but I don't see much incentive to make this happen in this day and age.

[+x=usr(1536)]

1 hour ago, Mathy said:

Hello guys

 

Hmm, I guess most of you are not getting my point.  Let me try to explain some more:

 

- Not everybody wants to open their 600XL to upgrade it to 64kB of main RAM.  And some of us aren't able to upgrade the 600XL to 64kB.  And for some reason don't want to send it to someone who does.

- The 1064 is hard to come by.  And size wise it's probably as small as they could have made it way back when.  A new replacement could be much smaller.

- There are plenty of devices that can act as an external memory upgrade.  Some even let you configure them as main RAM.  But can they provide 64kB of main Ram and at the same time offer the rest of the available RAM as a RAM expansion?

- Memory expansions ($D301, Axlon, etc.) and only 16kB of main RAM often just isn't gonna cut it.

I understand the points that you're raising here.  However, there's something I'm not totally clear on:

Quote

What I would like to see is a small 1064 replacement.  That plugs into the 600XL to get 64kB of main RAM.  And since the small 1064 replacement would have a PBI passthrough, you could plug an existing external memory expansion into the small 1064 replacement and you'd have an XL with 64kB of main memory and what ever amount of expanded memory ($D301, Axlon, etc.).

If I'm following correctly, what you would like is a PBI-attached 64K memory expansion with PBI passthrough - like a 1064, but in a smaller form factor.  From there, subsequent memory upgrades could be attached to the PBI port of that device to expand beyond the stock 64K.  Is this correct?

Quote

Plus you would not need different versions of an external memory upgrade ($D301, Axlon, etc.) for the 600XL and the 800XL.  It's cheaper to build a small 1064 replacement that can be used with any external memory expansion ($D301, Axlon, etc.) plus an external memory expansion ($D301, Axlon, etc.) than it is to build two different external memory expansions ($D301, Axlon, etc.), one for the 600XL and one for the rest.

Tell me if this sounds correct: what you are essentially describing is a 64K 'shim' upgrade that would sit between the 600XL and a Universal memory upgrade offering considerably more memory that would work on an 800XL (or, presumably, an XE with ECI port).  That shim upgrade wouldn't be required for any machine other than the 600XL.  Am I headed in the right direction?

 

If I am correct, there are two issues that I can see with doing this:

1. Having stacked PBI devices - even small ones with passthrough - will extend the depth of the 600XL past where an 800XL would end, negating any space savings.
2. While the Universal memory upgrade would have a potential market of every PBI- / ECI-equipped machine, the 64K one would only be useful for 600XLs.  They're a much smaller slice of the market, so the 64K shim device would likely be disproportionately expensive when compared to the Universal upgrade offering way more RAM.

What I'm wondering is if it might be possible to have something similar to @tf_hh's 576K upgrade, but connected to the PBI slot.  In all use cases, it would disable internal RAM regardless of size and provide 64K of base memory with 512K of extended RAM that could be paged in and out as necessary.  This way, there's only a single device needed for external RAM upgrades.  Should help with pricing as well as compatibility.

Edited June 15, 2021 by x=usr(1536)

[manterola]

I would love to see and have that: an tf_hh 576K expansion but external (PBI), with pass-thru (with the option to disable XRAM, and just provide the Std.64K)

 

[+bob1200xl]

I can see this as a cable on the PBI (like the MIO) and the memory module as a tidy 'bump' on the cable.

 

Bob

 

[+DjayBee]

4 hours ago, manterola said:

I would love to see and have that: an tf_hh 576K expansion but external (PBI), with pass-thru (with the option to disable XRAM, and just provide the Std.64K)

 

Then go and get yourself a SysCheck from him. ?

[Peri Noid]

Just to clarify: SysCheck, as it is right now, allows to fully substitute the basic 64K of RAM in a 600XL but the additional EXTRAM is not working. I just did an experinment with my machine and since it's already expanded to 64K of RAM, I just removed both chips. And this is what I got. I guess, it's just the matter of firmware so both basic 64K expansion and combined ones are possible.

 

Edited June 15, 2021 by Peri Noid