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1200XL - Wizztronics or Newell?


ryanr256
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  • 9 months later...

Your Antic will work fine in a 1200XL. just like the newer MMU which is a requirement for 1200XL 256K upgrade, IIRC. Though that's something I had to do anyway to install a new OS and PBI port on my 1200XL. The original Rambo might work with the 1200XL's original MMU. I've never installed Wizztronics or Newell's, but I've replaced a bad ANTIC with the CO21697 in my 1200XL. Of course now I have a PAL Antic in mine anyway.

Edited by Gunstar
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To add to Binarygeek's question: When you upgrade the 1200XL to 256K, do you lose the PORT B features on the 1200XL? Meaning, do you lose extended keyboard control and LED L1 and L2 control?

 

When I replace the 1200XL MMU with an 800XL MMU, do all the 1200XL F1-F4 keys and L1 & L2 LEDs still function the same?

Edited by ACML
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To add to Binarygeek's question: When you upgrade the 1200XL to 256K, do you lose the PORT B features on the 1200XL? Meaning, do you lose extended keyboard control and LED L1 and L2 control?

 

When I replace the 1200XL MMU with an 800XL MMU, do all the 1200XL F1-F4 keys and L1 & L2 LEDs still function the same?

Now those are some good questions. One part of the schematic has LEDs 1 and 2 controlled via PB2 and PB3, but another part of the schematic shows PB2/PB3 having no connections at the 6520.

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To add to Binarygeek's question: When you upgrade the 1200XL to 256K, do you lose the PORT B features on the 1200XL? Meaning, do you lose extended keyboard control and LED L1 and L2 control?

 

When I replace the 1200XL MMU with an 800XL MMU, do all the 1200XL F1-F4 keys and L1 & L2 LEDs still function the same?

Everything still works on the 1200XL as stock up to 256K. 512K or higher use bit 7 of port B which is what is used for Self Test and the other 1200XL advanced features you mention. These features are still hidden in the newer 600XL/800XL OS too, (so if you upgrade to XL/XE OS, they all still work on the 1200XL )but they don't have the function keys or LED's to take advantage. You can install a switch in 512K upgrades to revert to 256K and gain back bit 7 for these advanced features too. I just stick with my 256K Rambo now, I had it at 512K piggy-back at one point, but had issues with a lack of space under the keyboard pressuring the chips, not an issue on the 800XL though. But there are sram 512K upgrades, internal and external that will work in the 1200XL. Sorry, the external upgrades require the PBI of the 600/800XL's. I modded my 1200XL with a PBI and can use a Syscheck 2.2 512K external sram and switchable OS for more than 256K now, or soon will be, I haven't quite finished the PBI mod.

 

As to the Wizztronics working in a 1200XL, I've never installed one or look at instructions but my educated guess is yes, if the Wizztronics can work in an 800XL, then it can in a 1200XL, BUT, you would probably have to "upgrade" the 1200XL OS and MMU to the 800XL, Something that just should be done if your going to upgrade at all anyway. The instructions for upgrading the OS and MMU are contained with in the 1200XL PBI upgrade instructions here: http://retrobits.net/atari/pbi.shtml and they are also included in the Atarimax 256/512K Rambo upgrade installation instructions too, attached below.

 

Also, you can follow the instructions for the Atarimax 32-in-1 OS, and just stick an XL/XE revision B/C/D OS in place of the 32-in-1 at that point in the installation. But, if you are going to do the OS upgrade anyway, why not go beyond the stock 800XL OS and just install the 32-in-1 OS or, Bits Of the Past sell a 4-in-1 OS board too. The 1200XL has to be modified with new sockets no matter which route you decide to upgrade the OS, the added bonus is the OPTION for internal BASIC too, and the privilege of having to hold down OPTION to bypass Basic like other XL/XE owners, unless your choice is the 32-in-1, then you get OS's that reverse the OPTION key function!

 

https://www.atarimax.com/warpos/documentation/

https://www.bitsofthepast.com/?product=4in1-os-adapter

Atarimax 512k Memory Upgrade for 1200XL Computers.pdf

Edited by Gunstar
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PORTB bit 7 is the self-test bit on the 1200XL, just as it is on other XL/XE models. It's overloaded by the 512K RAMBO upgrade, but still functions as the self-test bit unless extended RAM is selected. PORTB bit 7 doesn't access any other "advanced features" on the 1200XL and the self-test will still work following an upgrade to 512K without any kind of hardware switch:

 

http://atrey.karlin.mff.cuni.cz/~pavel/atari/800xl512K.html

As for the LEDs, these are controlled by bits 2 and 3 of PORTB, and the same bits are employed for bank selection by the 256K and 512K RAMBO expansions (along with bits 5 and 6 or 5, 6 and 7 respectively). The LEDs remain wired up regardless of how much RAM is in the machine and will continue to work when you write to PORTB, but since writing to PORTB also bank switches extended RAM on an upgraded 1200XL, deliberate manipulation of the LEDs must be performed with caution. LED functionality is completely independent from the OS.

If the scope of the upgrade were to broaden to encompass multiple operating systems and 512KB, one might consider Ultimate 1MB, since it provides 1088K, 576K and 320K RAM models plus a choice of four operating systems which may be replaced by any four of your choosing. You also get four flashable internal BASIC slots and the opportunity to drive a cartridge-based PBI IDE hard disk without using a hacked operating system and without the need for a physical PBI connector. When using the newest U1MB firmware, one also gets BASIC suppression without the Option key and high-speed SIO operation regardless of the operating system in use. The board must first be modded for a single-chip OS, but no XL OS ROM IC or MMU is required.

Edited by flashjazzcat
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  • 7 months later...

Hello gilsaluki

 

Then again, I see NO reason for a RAM upgrade larger than 256K. Not many programs/demos that take advantage of 128K and above.

 

If more people would have bigger RAM upgrades, more software would be written that uses more memory. For years, people have been saying "we don't need to support bigger RAM upgrades, because only a few people have them".

 

Sincerely

 

Mathy

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But if the 'killer apps' and demos that come out more often require extra RAM as time goes on, it works as an incentive to upgrade machines too...

 

Like watching demos that are stereo capable, on a single pokey machine - you know there's something your missing... fueled my desire for that upgrade for decades, until finally installing one this year. but I guess in that case the demo still runs...

 

And with large fast cartridges with lots of ROM, or flash memory, the need for RAM in the Atari itself is diminished since things can be loaded/swapped very quickly...

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The program in question is not one of those listed. After Newell introduced the Omniview 80 column OS, they wrote a special modification for the 130XE version of Atariwriter Plus. You had to send them your AWP disk and they would modify it and return it. That was prior to the XEP80 and it was an 80 column version of AWP. It only works on the 130XE. I have not ben able to make it work on an XL with the Rambo or Wiztronics upgrades but it will work on an XL with the Newell upgrade if you have a switch that selects banked or main. I am not sure of what the switch does but I bought an 800XL on eBay that had one and the AWP+80 worked in one position and it didn't in the other position.

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The program in question is not one of those listed.

After Newell introduced the Omniview 80 column OS, they wrote a special modification for the 130XE version of Atariwriter Plus. You had to send them your AWP disk and they would modify it and return it. That was prior to the XEP80 and it was an 80 column version of AWP. It only works on the 130XE. I have not ben able to make it work on an XL with the Rambo or Wiztronics upgrades but it will work on an XL with the Newell upgrade if you have a switch that selects banked or main. I am not sure of what the switch does but I bought an 800XL on eBay that had one and the AWP+80 worked in one position and it didn't in the other position.

It doesn't work on RAMBO/Wiztronics upgrades because the 130XE uses bit 5 to toggle whether the ANTIC sees banked/extended RAM, whereas most XL style RAM upgrades use that bit for additional CPU banking. (They were designed before the XE's) You could optionally install a switch to restore bit 5 to ANTIC access, at the expense of reducing a 320K XE to 192KB. I'm guessing this is what your switch does. 800XL without a Freddie MMU can't run Omniview 80 Column AtariWriter+ because the MMU does not have the separate ANTIC capability. Well.. It will run, but the display will be messed up...

 

"Compy-Shop" XL/XE style upgrades preserved ANTIC banking by using another PIA bit.

 

This was discussed earlier this year in this thread: http://atariage.com/forums/topic/275696-atari-80-column-softwarehardware/

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