XL/XE memory upgrading

[carmel_andrews]

Is it possible to upgrade the xl/xe ram using ste/ old stylee pc simms boards

 

i've heard it's possible but not seen or heard of anyone actually doing it

 

just curious.....

Edited September 6, 2007 by carmel_andrews

[ndary]

http://satantronic.atari.sk/1MBRAM_SMMMU/index.htm

[Allas]

Is there any way to expand the memory only via slot bus or cartridge?

Edited September 6, 2007 by Allas

[MEtalGuy66]

Is it possible to upgrade the xl/xe ram using ste/ old stylee pc simms boards

 

i've heard it's possible but not seen or heard of anyone actually doing it

 

just curious.....

 

Yeah you can use a 30 pin SIMM in place of a bank of 8 DRAMS on any of the PD upgrades Ive seen. Just get the pinout for the SIMM and match up adress, data, CAS, RAS, and WE.. It actually ends up being a whole lot less connections because alot of the signals are hooked common on the SIMM.

 

for instance lets say you have an 800xl and you are doing the claus bucholz (classic) 256k upgrade... instead of replacing the 8 64kx8 DRAMS with 8 256kx8 DRAMS, just use a single 30 pin SIMM. it can be 256k, 1 meg, 4meg, whatever.. Your only going to hook up enough adress lines for 256k..

 

same thing with the scott petersen 320k upgrade for the 130xe.. instead of replacing the 8 64kx8 drams on the extended bank with 8 256kx8 drams, just use a 30 pin SIMM. works fine..

 

Some major benefit of this approach are that the simms draw much less power than the older DRAMS, have on-board decoupling caps, and take up less space..

 

Now. to answer the NEXT question that you are likely to have....

 

What about extended ram upgrades larger than 256k?

 

Well, as we all know... ANTIC only refreshes (8-bits) 256k of memory.. All of the larger common atari memory upgrades (with the exception of the SATANTRONIC, BOB WOOLEY, and MATHIUS VAN NISSELROY 1 meg SIMM upgrades) are built out of "banks" of 256k.. All adress lines, all data lines, RAS, and WE are hooked common between the 256k banks.. The memory upgrade logic creates a separate CAS line for each bank. In this way, (since antic employs RAS-only refresh and thus only utilizes ras and the adress lines on a refresh cycle) all banks are refreshed simultaneously. A memory access cycle however, is still specific to whichever "bank" of 256k we are accessing, depending on which bank we have pulled cas low for.

 

SO what does this mean?

 

Well, what it means is this: we can do the larger memory upgrades (such as the bucholz/rambo 512k/1024k XL or the petersen 576k/1088k XE) with simms with the standard logic in place, but wed have to use a separate SIMM for each 256k (which would normally be a set of 8 chips so this is still a great savings in terms of power and space.)

 

However..

 

If we want to do these upgrades using a SINGLE SIMM for ALL of the memory, we have to change the logic to use a single CAS signal, and also generate the extra bits of adressing during both memory access and refresh cycles... This allows the memory to be adressed as a single large contigous (10-bit) chunk, instead of selecting between 2 or 4 smaller 256k chunks. The refresh can be taken care of by using "cas before RAS" (also known as "automatic") refresh. Most if not all SIMMs employ new enough DRAM chips that support this alternate method of refresh. This is how Bob Wooley handles the refresh problem in his 1 meg SIMM upgrade.. SATANTRONIC actually employs logic to create a full 10 bits of refresh row adress setup, and continues to employ the traditional "RAS only refresh method.

 

Ok. If I lost you, Im sorry.. But that is the truth of the matter.

[Artlover]

http://satantronic.atari.sk/1MBRAM_SMMMU/index.htm

Interesting. Tobad my 800xl is already upgraded with 256k as per the old piggy-backed chips method, or I'd do this in a heartbeat. Got a bunch of old 30pin simms not being used for anything.

 

Is there any way to expand the memory only via slot bus or cartridge?

I "may" be wrong, but if my memory serves me correctly. No, at least not as directly bankable system memory. Yes for a software dependent ram disk type thing.

 

Like on the C-128, adding banked system memory means adding logic and tapping internal points that don't exist on the external ports.

[MEtalGuy66]

I "may" be wrong, but if my memory serves me correctly. No, at least not as directly bankable system memory. Yes for a software dependent ram disk type thing.

 

Like on the C-128, adding banked system memory means adding logic and tapping internal points that don't exist on the external ports.

 

Well, anything other than the first 64k of system memory is accessed in one bank-switching scheme or another.

 

Personally, I like the way the MIO ramdisk works.. It gives you 1 megabyte of ram but only takes up 256 bytes of the ATARI's "memory map"... And since it does not rely on the computer for refresh, it is "non volatile". As long as you leave the power to the MIO on... In fact if you configure it as a ramdisk, you can assign it as d1: and boot from it. If you are using a multiplexer system, you can boot ALL YOUR ataris from it, at full ram-disk speed.

 

And yeah, it is an external device that plugs in the PBI/ECI slot.

[Mathy]

Hello MEtalGuy66

 

... BOB WOOLEY, and MATHIUS VAN NISSELROY...

 

That would be "Mathy van Nisselroy". And "Bob Woolley'. (double "l")

 

BTW mine also uses automatic refresh. All 1 megabit and up RAMchips support it.

 

I hope to one day replace the DRAM's with SRAMs. They don't need to be refreshed at all.

 

Greetings

 

Mathy

[MEtalGuy66]

Hello MEtalGuy66

 

... BOB WOOLEY, and MATHIUS VAN NISSELROY...

 

That would be "Mathy van Nisselroy". And "Bob Woolley'. (double "l")

 

BTW mine also uses automatic refresh. All 1 megabit and up RAMchips support it.

 

I hope to one day replace the DRAM's with SRAMs. They don't need to be refreshed at all.

 

Greetings

 

Mathy

 

Man, I am so sorry. I have butchered your name so many times. And really, I have no excuse. I promise Ill check the spelling next time.

I knew about the spelling for Bob's name. That was actually a typo..

 

Anywayze. Did you ever get all the phase 2 clock issues ironed out in that 1 meg XEGS? I havent checked your site in a while.. Been real busy.. (over a year actually)

[Mathy]

Hello MEtalGuy66

 

Don't sweat it. If people would pay me a dollar (or better yet a Euro) everytime my name is missspelled, I'ld be rich by now. Maybe I should have used a smiley.

 

BTW I prefer to use real first names. Guess why I'm not using yours....

 

The 1MB XEGS doesn't have the timing problems. The 1MB 800XE does. I have this personallity disorder that (among other things) results in me not getting a lot of stuff done. But it's still on my "to do" list.

 

I know you're busy. Hope you can still find the energy to finish it. Must be getting boring from time to time.

 

Greetings

 

Mathy

[MEtalGuy66]

I know you're busy. Hope you can still find the energy to finish it. Must be getting boring from time to time.

 

Greetings

 

Mathy

 

If you're referring to the MIO project, they are all sitting right here. But my life has gotten REAL busy..

[peteym5]

I like this memory upgrade. I am wondering it it supports separate Antic (Video) access? I heard once you go beyond a certain point, you have to use bit 5 in PORTB to as an extra bit for CPU bank access. Some People got around that by using a 2nd PIA chip and/or have a external switch that goes between XE compatibility with basic and just straight bank switching and using the Basic Bit as a bank indicator. I also heard about a whole different memory controllers being used. Removing ROM Basic is not normally a huge concern, people can Turbobasic XL from disk.

 

Something else I thought about is using another byte from PIA to indicate extra banks, PBCTL at 54019 $D303 is unused in the XL/XE computers and all the bits are available.

Edited September 7, 2007 by peteym5

[MEtalGuy66]

I like this memory upgrade. I am wondering it it supports separate Antic (Video) access? I heard once you go beyond a certain point, you have to use bit 5 in PORTB to as an extra bit for CPU bank access. Some People got around that by using a 2nd PIA chip and/or have a external switch that goes between XE compatibility with basic and just straight bank switching and using the Basic Bit as a bank indicator. I also heard about a whole different memory controllers being used. Removing ROM Basic is not normally a huge concern, people can Turbobasic XL from disk.

 

Something else I thought about is using another byte from PIA to indicate extra banks, PBCTL at 54019 $D303 is unused in the XL/XE computers and all the bits are available.

 

If you are asking about the satantronic 1 meg upgrade, yeah it does. But you have to order their super-emmu.

 

In fact.. Its the ONLY upgrade Ive seen that you can install in an XL and make TRUE 130xe compatability, in that respect.

 

XE Extended video is awesome.. Too bad so few coders have utilized it... Id like to see some software that really pushes it's limits..

[+warerat]

Something else I thought about is using another byte from PIA to indicate extra banks, PBCTL at 54019 $D303 is unused in the XL/XE computers and all the bits are available.

 

PBCTL is not unused. It is the port B control register. Those bits control the data direction for port B (which is output on XL/XE) as well as other functions. It is not an I/O register.

[Mathy]

Hello guys (and girls?)

 

My 1MB XEGS uses $D301 only.

It still has separate ANTIC and CPU access.

It still has software control over BASIC, OS RAM/ROM, the Selftest and Missile Command.

It will load TurboBASIC from RAMdisk without flickering.

 

What it basically does, is freezes the status of BASIC, OS, Selftest and MC when either PB4 or PB5 or both goes low.

 

Greetings

 

Mathy

[MEtalGuy66]

Hello guys (and girls?)

 

My 1MB XEGS uses $D301 only.

It still has separate ANTIC and CPU access.

It still has software control over BASIC, OS RAM/ROM, the Selftest and Missile Command.

It will load TurboBASIC from RAMdisk without flickering.

 

What it basically does, is freezes the status of BASIC, OS, Selftest and MC when either PB4 or PB5 or both goes low.

 

Greetings

 

Mathy

 

Yeah, but unless youve added logic to take care of the functions of the 130XE EMMU, you dont have true 130xe extended video mode..

 

In any case.. That sounds like a really good expansion design. You should publish it, and we can work up versions for all the other 8-bits.

 

Have you found any incompatability issues at all? What software does it work/not work with?

Does XRAM see all of it?

Edited September 7, 2007 by MEtalGuy66

[+warerat]

Yeah, but unless youve added logic to take care of the functions of the 130XE EMMU, you dont have true 130xe extended video mode..

 

You and your damn ANTIC mode.

 

His design fully supports it as he's using CASBNK from the EMMU as his CAS.

[Mathy]

Hello MEtalGuy66

Yeah, but unless youve added logic to take care of the functions of the 130XE EMMU, you dont have true 130xe extended video mode..

 

I've added a co25953 (you call it the EMMU). But I discovered that U35 on the 130XE schematics is a 74LS95B. So we can use a GAL plus a 74LS95B instead.

 

Have you found any incompatability issues at all? What software does it work/not work with?

Does XRAM see all of it?

 

XRAM does see it. As do most other RAMdisk testers (IIRC the only one that only sees 64 + 512 kB is PAGEFIND. But that's probably because the person who wrote it made a judgement error). BASIC XE crashes in extended mode, because of sloppy programming. And demo's that use extended memory, but don't test which banks are available, might not work (I've tested some.)

 

BTW the links to my upgrade should be on my homepage at http://www.mathyvannisselroy.nl

 

Greetings

 

Mathy

[MEtalGuy66]

Yeah, but unless youve added logic to take care of the functions of the 130XE EMMU, you dont have true 130xe extended video mode..

 

You and your damn ANTIC mode.

 

His design fully supports it as he's using CASBNK from the EMMU as his CAS.

 

One day Im gonna make a program that does some amazing shit thats gonna make you eat your words, and bust out your PAL burner, heheh.... Next thing you know, the famous WareRat 576k 800 will be TRULY XE compatable.. heheh.