1024k RAM upgrade

Hello Pancio,

I have read about your 1024K RAM upgrade in the forum. You should know that the Hias 512k version is also based on the 512k mega-hz version (or they developed it together?). At the moment I have five Atari 800XL computers, four of them are upgraded with 512k XRAM:

a) 2x 800XL with 512k SRAM upgrade by mega-hz (can use switches to switch between Rambo and Compyshop modes; I was lazy and did not use switches, so I always have 576k mode with both CS and Rambo banks active; advantage: no need to choose between Rambo or CS, dis-advantage: no sep. Antic access)

=> almost all my A8 programs work with them, exceptions are programs that require sep. Antic access and programs that require 1MB RAM

b) 2x 800XL with 512k SRAM by tf_hh (it does not use switches and can be switched via software; it also supports sep. Antic access; advantage: in 576k mode no need to choose between Rambo or CS, 256k CS only mode with sep. Antic access; dis-advantage: some programs switch banks during or after loading and make the computer crash or they do illegal writes to port B and crash the machine, ouch)

=> there are several commercial and freeware programs that do NOT work with these enhancements, which is a pity!

I have created a small test-collection of programs that do NOT work with the tf_hh upgrade (or to be more precise: internal tf_hh 512k upgrade, tf_hh Sys-Check with 512k and external Zaxon 512k PBI or ECI/cart upgrade, based on the tf_hh upgrade). I am very interested in your upgrade, but maybe you can do me a favor and test these programs with your 1024k RAM upgrade in 576k CS mode, 576k Rambo mode and 1088k Rambo + CS mode ?!? Would be very interested to hear if these programs work or not... some names:

• Great American Cross Country Road Race (GACCRR) by Activision; main game screen does not appear (stays black/blank) with tf_hh enhancement; solution: XRAM must be switched off;
• GACCRR by Firebird/Silverbird: same as above!
• Asteroids by Atari UK (tape version!): Asteroids do not appear, game therefore unplayable with tf_hh enhancement; solution: XRAM must be switched off;
• Tapper by Sega/US-Gold (tape+disk): Start/title screen does not appear, game unplayable with tf_hh enhancement; solution: XRAM must be switched off;
• Up N'Down by Sega/US-Gold (tape,+disk): same as above!
• X-Demo by MadTeam, requires 320k RAM (Rambo afaik), stops loading in 576k mode with tf_hh enhancement; solution: switch down to 320k CS or Rambo mode;
• 2 Unlimited (sample) Demo by ???, requires 128k RAM, shows garbage during loading with mega-hz enhancement in 576k mode but in the end it works! shows garbage and crashes completely in 576k and 320k modes with tf_hh enhancement; no solution found!
• Beta Lyrae by Databyte (tape and disk): screen stays black/blank after loading with tf_hh enhancement, game unplayable; solution: switch XRAM off;

Thats all so far, think I have some more problematic programs with the tf_hh enhancement, but have to find them first. As said before, I would like you to test these programs and tell me the results... of course I can attach the programs here or send them by e-mail.

Greetings, Andreas Koch.

Hi,

Thanks for additional info regarding another author - I will update post with this to avoid misunderstandings...

According to my implementation.. It's the same like described by you in a) bullet... but CS mode is double sized (+64k base memory of course) - you should know, it's not standard but it's possible :-) , so, should be enough for most programs. In case you need more e.g. for demo Rewind/New Generation, Rambo mode is required... anyway, there is no automatically mode detection but (!) the plan is to add additional micro-controller, EEPROM with 4 OSs and possibility to set memory mode by keys combination. I'll start tests when first PCB will be assembled. That's solution for lazy :-) One more notice according to XRAM.. nowadays there is no issue with recognition which XRAM you have, special procedure shall be used (MADS/MADPASCAL) like PeBe in MCplayer. Of course this solution is dedicated for new software but I like this method so much.

Regarding tests.. sure I'll do these for you. Will be helpfully if you provide the software pack to me.

Best Regards, pancio

Hello Pancio,

sorry for the late reply, but attached you will find the programs that do NOT work with the internal 512k tf_hh RAM upgrade and several other upgrades that are based on it (switching banks via software).

Hopefully you will find the time to test these programs and tell me the result (which programs work and which ones do not work - and maybe also what behaviour the programs show that do not work, e.g. blank screen, garbage, etc.)

Greetings, Andreas Koch

Hi Andreas,

Thank you for sharing with programs. Yesterday's night I made and run first prototype.. it was very painfully and full of failure Atari was dead for many hours... of course because of some stupid mistakes on the PCB which I probably will describe soon in the appropriated topic on the Forum. So, actual state is: Atari working with additional SRAM... 63 banks were discovered and no errors ware detected (checked by 2 programs).

Encouraged to take further action, I started checking your programs... and only one started (some Polish demo) but only partially. So I figured something was wrong. I also checked how the Numen demo, requiring 320KB, was loaded and it was also a failure!

Conclusion? Something went wrong... I suppose it's hazard with a combination system at the junction of GAL and additional TTL gates. I need to put the project aside for a moment to look at it from a different perspective (actually I would do it already but I can't find the probes for the logic analyzer - I had to order new ones :-) )

So, you just have to wait a while :-)

Best Regards, pancio

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