RAM Upgrade Applications

[MEtalGuy66]

Well, your definition of a "defacto standard" doesnt match mine, thats for sure..

 

I'd always known "de facto" standard to mean something that's in common practice, but isn't necessarily a written standard ("de jure"). In this case, I think that utilizing bits of portb to do ram banking definitely fits the description of "de facto".

 

I'd be interested in your upgrade, I always cringed at doing a SIMM upgrade with all the wires hanging all over the place, even though I have a box of 30-pin 1MB SIMMs I've been saving for that purpose. A plug-in option is so much cleaner!

 

Ok.. Well, if there actually is some place that it is ALL written down, then I'll give you the "defacto" part.. But I still wouldnt call it a standard.. How about a "defacto list of possible implementation schemes"

heheh...

 

Maybe Im just a purist in terms of hardware compatability.. I have 4 130xes set up. only one has a ram upgrade (petersen 320k), and it's got a switch to put it back "stock".. I also dont run any custom OSes.. (with the exception of the Multiplexer which can also be switched back "stock" on all of the machines).. Theres nothing that pisses me off worse than having to jack with my hardware, in order to get some software to run. I really hate "user/hardware base fragmentation" caused by "hacks" that are designed to be the cheapest/easiest thing to do, rather than the most compatable.

 

Another point I'd make is that even if we call "PORTB" the "standard" for memory upgrades, you hit a 2 megabyte barrier, even after you've used every possible bit that can be "hijacked" to control additional memory adressing. At this junction, we can either ass-wire another entire PIA into the system (thus occupying another 256bytes of 6502 adress space) just to get 20 more bits of control registers, or.. we can simply decode our own adressing to single 8-bit regsisters, one at a time as we need them, using standard logic. Well, given that a single 8-bit regsiter takes us to 16megs (the largest cheap and commonly available 8-bit memory device being a 16meg 30 pin SIMM,) why not use all 8 of those bits for our upgrade, and "give back" all of the standard atari features that are controlled by PORTB... This creates a transparently compatable upgrade of maximum practical size and puts BASIC ENABLE, SELF-TEST ENABLE, and SEPARATE ANTIC/CPU ACCESS back where ATARI intended them to be.. The two largest (by far) common denominators of software compatability in terms of RAM configuration are those of factory ATARI configurations (64k XL/XE and 128k 130XE).. This upgrade will be 100% transparent to both of these...

 

Lastly, for those who DO want an "all in one" upgrade that covers 90% of the "traditional" memory upgrade schemes via hardware switched "modes," you really need to get one of the Mega-hz SRAM/NVRAM upgrades. I spoke with him a while back concerning the details of "compatability modes" supported by his upgrade, and I was impressed. It's pretty much the "all-in-one" solution, and the PCB is designed to go in just about any XL/XE series machine. This is a fairly advanced upgrade and not something you would want to try to build using "DIY" wiring methods or standard TTL logic ICs.. It comes as several small PCBs that can be installed neatly and professionally by anyone with basic electronics/soldering skills.

 

If you do a search on these forums for the machines Beetle has built, you'll see pictures of some good example installations of the Mega-hz SRAM upgrade..

Edited June 11, 2008 by MEtalGuy66

[Mathy]

Hello Ken

 

Mega-hz designed the PCB. BigBen designed the upgrade. And toke a good look at my 1MB XEGS upgrade. I'm not sure however, how much of it he used.

 

Greetings

 

Mathy

[BigBen]

Hi MEtalGuy66,

 

my name is Bernd and I was the constructor of the 512k SRam memory extension.

After all test are successfully done Mega-hz create the PCB, add the akku buffer and memory protection to it.

 

Here you can see some pictures of my first version.

 

http://www.abbuc.de/modules.php?name=Forum...sc&start=40

Push the "Lichtorgelfilm" button to look a flashing LED´s from a 1200XL.

 

Yes, the 512k Sram runs on all XL/XE/XEGs inclusive the 1200XL. 3 years ago without any trouble and problems.

I think next year I will offer the circuit diagram and GAL logic.

 

Over 2 switch you can change the mode:

512k memory on

256k CompyShop memory on

256k Rambo memory

memory off

 

My friend HardwareDoc create his own 1Mbyte Sram extension - look at the end of the side.

 

Thank Mathy for your information.

 

Bernd

[MEtalGuy66]

Yeah, Beetle just upgraded his to 1 megabyte as well (by using PB1 to enable a second 512K SRAM instead of internal BASIC).

 

By the way, thats a VERY NICE prototype board, Bernd.. Looks like something I would make

Edited June 11, 2008 by MEtalGuy66

[BigBen]

Yeah, Beetle just upgraded his to 1 megabyte as well (by using PB1 to enable a second 512K SRAM instead of internal BASIC).

 

By the way, thats a VERY NICE prototype board, Bernd.. Looks like something I would make

 

I think the same what you say.....

 

But I make a little mistake. The link is not the 512k memory extension it was the 128k memory replacemend for the original memory.

It makes every 1200/XL/XE(64k) Atari into an 130XE with 128k. Look at the front you can see the 6 dram memory chips of the computer.

 

Here the new correct link:

http://www.abbuc.de/modules.php?name=Forum...;highlight=sram

 

 

Bernd

[MEtalGuy66]

So my last question is where can this upgrade be purchased?

 

Do you or Mega-hz currently sell it through ABBUC or some other website?

[BigBen]

So my last question is where can this upgrade be purchased?

 

Do you or Mega-hz currently sell it through ABBUC or some other website?

 

The ABBUC don´t sell it.

Mega-Hz website is only in german. It looks like that the memory expansion is sold out.

http://mega-hz.no-ip.com/Angebote/angebote.html

This was the first-generation of pcb.

http://mega-hz.no-ip.com/ATARI/ATARI%208Bi...re/512K%20SRAM/

I send him an email and wait of his answer.

 

Bernd

[Tezz]

So my last question is where can this upgrade be purchased?

 

Do you or Mega-hz currently sell it through ABBUC or some other website?

 

The ABBUC don´t sell it.

Mega-Hz website is only in german. It looks like that the memory expansion is sold out.

http://mega-hz.no-ip.com/Angebote/angebote.html

This was the first-generation of pcb.

http://mega-hz.no-ip.com/ATARI/ATARI%208Bi...re/512K%20SRAM/

I send him an email and wait of his answer.

 

Bernd

I spoke with Wolfram (mega-hz) via email a couple of weeks ago, the SRAM PCB's are due at the end of the month.

[BigBen]

Hi MEtalGuy66,

 

I got the answer of Mega-Hz (Wolfram) today. He has no more 512 k circuit boards. With the new 512 k circuit boards it still will last for what there still other circuit boards shall be ordered.

 

The 512 k circuit boards were never offered on his web page.

 

Bernd

[ClausB]

I have spent some time looking for the original Byte article, of course to no avail, just to see what was said about ramdisks way back when.

Here's the last section of the article - about the RAMdisk software.

Just noticed that I never posted the whole article, so here it is.

[_The Doctor__]

Thanks again ClausB, I wish everyone was helpful as you have been.

 

On a side note you tried to help with a memory toggle switch issue I had dealing with Antic access and a 320 XE. I am glad to say after thinking about it... it worked out. I still think it could be improved since it leaves a line floating when in off or stock position. But it did what it had to. Antic mode works in both positions... 192k and 320k. So it effectively made a 192k or 320k peterson with antic access still working.

Edited February 4, 2009 by _The Doctor__

[ClausB]

Thanks again ClausB....

I'm just glad to help us all keep the Atari spirit alive!

[netcoord99]

I have spent some time looking for the original Byte article, of course to no avail, just to see what was said about ramdisks way back when.

Here's the last section of the article - about the RAMdisk software.

Just noticed that I never posted the whole article, so here it is.

 

Cool Claus.. Hey were you the one that made the ACE Midiface gadget? I still have it and would like to sell it. It will come with MidiTrack II. I don't even know how to use it so maybe someone else here knows. You got any docs on it?

[ClausB]

Here's the whole BYTE article in PDF, scanned by ThumpNugget:

 

Quarter-Meg Atari from BYTE Vol 10-09 1985-09 10th Anniversary Issue.pdf

[mutterminder]

Wow, I believe this is how I got my original 800XL expanded. I subscribed to BYTE until the very end. Through the seventies and 80's they always had cool projects like this. Is there an on-line archive of all of the old issues?

[ClausB]

Yes, a user here scanned many issues and posted them here, I think in the Classic Computing forum. His and others' scans are also archived elsewhere on line. Search for it.