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Alfred

Odd 1200XL

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So there was an ebay listing for a 1200XL that just ended. What was odd was in the screenshots, there was one that showed a memory test that said the XL had 40 odd banks and that it was a 1088K machine. I wasn't aware there was a 1088K mod for the XL machines. All the text files I have are for Peterson upgrades for 320K, 576K and the 1088K. Is there really such a thing as a 1088K XL ?

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21 minutes ago, Alfred said:

So there was an ebay listing for a 1200XL that just ended. What was odd was in the screenshots, there was one that showed a memory test that said the XL had 40 odd banks and that it was a 1088K machine. I wasn't aware there was a 1088K mod for the XL machines. All the text files I have are for Peterson upgrades for 320K, 576K and the 1088K. Is there really such a thing as a 1088K XL ?

This machine likely had a U1MB(Ultimate 1 megabyte) upgrade installed. 

 

A less likely possibility is the Newell 1MB upgrade, this is an older upgrade using 8 - 1M x 1bit DRAM. I have an 800XL with one of these.

Edited by BillC

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I wasn't aware there even was a 1MB Newell board, I thought he just had the 256K board. Interesting.

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I saw this auction and was curious about it.

 

https://www.ebay.com/itm/ATARI-1200XL-Home-Computer-CONSOLE-NO-Power-Supply/223710401230?hash=item34162dd2ce:g:xrYAAOSwzF1dqTOr#vi__app-cvip-panel

 

Based on the condition of the machine, I assume that it wasn't a U1MB though.  The U1MB is new enough that I would expect to find a cleaner looking machine.  This one looks like it must have sat around unused for quite some time.  It must have been the Newell upgrade. 

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7 hours ago, Alfred said:

I wasn't aware there even was a 1MB Newell board, I thought he just had the 256K board. Interesting.

The manual is available: https://archive.org/details/NewellIndustries1MEGXLManual

It's even ANTIC mode capable, but looses ability to control BASIC ON/OFF.

 

Wes apparently modified the upgrade to be capable of up to 4MB, and also had versions for the 65XE/130XE.

Manuals/information for many products available at archive.org:

https://archive.org/search.php?query=wes newell

Edited by BillC

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I always thought the upgrades past 320K were overly intrusive to the functionality of the system. Even in the case of the Newell 1Meg XL here... it does seem to be 1088, not 1024K as the 1MB of RAM is on a separate board, and does not replace the original 64KB...

 

Method #1 retains ANTIC banking control via PIA bit 5, but internal BASIC and self test are must be controlled with external switches. For Atari and Omniview OS's self test needs to be enabled during powerup because the OS jumps through the selftest code...

 

Method #2 allows OS and BASIC ROM control via the PIA, but "extended memory" is permanently enabled for both CPU and ANTIC, costing you 16KB due to loss of access to the base 16KB in the banked memory area.

 

Method 3 loses software control of BASIC & OS, losing the 14KB "under the OS", but CPU and ANTIC banking are retained.

 

I guess 4MB is possible by assigning all 8 bits to banking... This would be 4MB minus 32KB (no 16KB RAM - 14KB usable - under the OS and no 16KB base ram in the banking area) ... external switches would be needed to toggle self test for bootup, and internal BASIC. ) Yep I see 4MB is mentioned at the end of this page: ftp://ftp.pigwa.net/stuff/collections/SIO2SD_DVD/Extension/Memory Upgrade/Atari XL 8-bit Memory Upgrade Page.htm )

 

I was intrigued how the "Modern" upgrades like Sys-Check, U1MB, are able to provide access to 1MB of RAM with NO compromises to Self Test, OS ROM, and BASIC...

 

I came across a post archived on @Mathy's site, which I think is where the original idea came from to retain full graceful software control of the function of PIA bits 0,1 & 7 retaining their original function when extended RAM is not enabled, and also allowing them for use as RAM bank selects when extended memory is activated on bit 5. The only requirement is that the extended memory has to be enabled before setting the banking bits. As written in the article, it is indeed amazing noone thought of it before 1991!

http://www.mathyvannisselroy.nl/memup.txt

Message 84        Sat May 11, 1991
R.GORANSON2 [HackMan]        at 12:08 PDT
 
   We'll everyone after a leave of absence I am back and hacking away at
everything at sight.  I have finally decided to set down and document all of
these  gizmos that I have been building for my 800xl and hopefully will be
uploading them all here soon.   I have come up with a simple two chip
modification that you can install in you memory upgrade that bank selects in
the $d301 that will allow you access to basic, OS on/off and diagnostics
without a switch even when you are using those bits for a memory upgrade. 
ALL I use is a 7404 chip and a 74ls373 a transparent data latch.  It is so
simple that I can&t believe that no one has come up with this before.  I am
currently using this little circuit with my own do it yourself 512k ram
upgrade soon to be 768k ram upgrade, and maybe soon 2M.  The only thing is
that my ramupgrade uses 256k chips and builds off of a newell industries 256k
or a rambxl.  I mean stacking 256k ram chips 8 high to get 2 full megs?!?  I
don't know if I will go that far as my BBS doesn't need that kind of space. 
(8high x 8long = 64 256k ram chips, geez!!)   anyway my little ramupgrade
uses the circuit with the 74ls373 and the 7404 to free up the OSbit,basic
bit, and diagnostic bit so I can use them to bank select memory,  then I just
have another circuit added on with a 74f02 and a 74f138 to decoded the three
bits to bank select 8 banks of 256k chips.
   I only use 3 latches of the 74ls373 so I am thinking of going with its
baby brother that only has 4 latches to makes things smaller.  I will have
the documentation on the two chip modification to make diffrent ram upgrades
able to switch all 3 bits off and on probably next week.
        WHat the two chips do is only allow the os bit,basic bit, diag. bits,
to change when bit 5 is high.  And when bit 5 goes low it latches the 3
control bits before they change.  That means that you can select basic
on/off, os on/off, and diag on/off if you have bit 5 is high (your are not
using extended ram.)  And if bit 5 is low,(you are using extended ram.) then
you can not switch any of the three bits.  The only thing I am wondering
about, does any software try to turn OS roms off/on while the extended ram is
enabled??  Such as MTOS or SNAPSHOT???  Anyway see you guys around.

 

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Need an full name of memory test on their oddly 1200XL with 1088k aka 1 mb. Can you (anyone) willing to created .ATR disk image for this particularly memory test ? Thank you ...

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5 hours ago, Caterpiggle said:

Need an full name of memory test on their oddly 1200XL with 1088k aka 1 mb. Can you (anyone) willing to created .ATR disk image for this particularly memory test ? Thank you ...

Thank you for offer 1 of those file. xex but not that one. The image is below from eBay oddly 1200XL. I want this file either ATR or XEX from below there...

Memory Test.JPG

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