SIDE2 behaves different between stock 600XL with 1064 and stock 800XL

[trekkie22]

I made an interesting discovery today with my SIDE2 Cartridge.

 

First some basics - I own a 600XL in stock configuration, with 1064 expansion, a 800XL in stock configuration and my "daily driver", a 130XE that I freshly extended with a U1M from Lotharek this week and that has a built-in a SIO2SD that I added a long time ago. I also own a SIDE2 cartridge since 2015, but the SIO2SD i built into the 130XE was always "good enough" and familiar, so I never used the SIDE2 much. Yesterday I decided to give the SIDE2 a go together with the U1M and updated it's really ancient firmware with the most recent one from FJC. Had a few issues with that because UFLASH didn't like the Cart at first, but the alternative way with SIDE2.COM worked fine and after the update UFLASH also started to work. Flashed the SIDE2OSS ROM. So far everything works great on the 130XE with U1M.

 

Today I wondered what happens if I use the SIDE2 with the other machines and discovered an interesting difference between the 800XL and the 600XL with 1064. As I had not used both machines for a longer period of time this was intended to also test the machines to make sure they still work fine - I loaded the CF Card with games and digged the machines out of storage.

 

I am aware that the 64K of a stock machine is only enough for basics, so I didn't expect too much.

I first tested the 600XL and everything worked surprisingly well - I could run games using the SIDE Loader. I tried SpartaDOS X - everything was accessible and I could even run SIDECFG and switch the ROMs:

Tried UFLASH and got a "179 Memory conflict", but that was expected. If I remove the 1064, the SIDE2 is not able to run at all. So far, so good. The 600XL seems to work fine.

 

Then I tried the 800XL and to my surprise it behaved differently - the SIDE Loader was not able to detect the CF card properly:

I then switched to SpartaDOS X - after turning on the machine, drivers were loaded, but no partitions visible or accessible:

If I reset the machine with the reset button, I can access the CF card and the partitions on it:

But trying to run SIDECFG gives me a "179 Memory Conflict" here.

 

I first thought that the machine might have hardware problems, but it works fine otherwise - the builtin memory test is fine and I was able to run several games from an external SIO2SD without problems. So the hardware of the 800XL also seems to work fine to me. But now I'm lacking an explanation, why the machines behave differently.

 

The only idea I got after a lot of googling: Does anybody know if the SIDE2 is able to use the 16KB RAM of the 600XL that the 1064 disables by default? From my understanding it should be the only difference between the two machines and 16k more memory might really be the big difference here. Otherwise I am lost what the problem of the 800XL is, that the SIDE2 behaves so different with the same amount of memory while everything else seems to work.

 

Would appreciate any help in getting this sorted out. The 600XL and the 800XL were my first two computers, so I want to keep them in stock configuration and working as good as possible.

Edited August 18, 2022 by trekkie22
typo and clarification of how UFLASH behaved after the firmware update

[flashjazzcat]

16 hours ago, trekkie22 said:

But trying to run SIDECFG gives me a "179 Memory Conflict" here.

That's because MEMLO is ridiculously high owing to the fact there's no extended RAM on the 800XL and the SIDE driver is wholly installed in low RAM.

16 hours ago, trekkie22 said:

Does anybody know if the SIDE2 is able to use the 16KB RAM of the 600XL that the 1064 disables by default?

It can't, no. The original 16K of base RAM will be completely deactivated by the 1064, AFAIK.

 

The most likely explanation for the 800XL behaving differently (and intermittently so, given the effect of pressing the RESET key) is that it has different bus capacitance and timing issues to the 600XL, and this is causing issues with that particular CF card. Maybe it's worth cleaning cart contacts on the 800XL as well, but intermittent failure to detect the card suggests a hardware problem unique to SIDE and that particular machine.

 

[trekkie22]

Never thought about timing issues as I had experienced the Atari as really stable in this regard, but it makes sense.

 

As that machine is something special to me and I'm really curious, I'll investigate further, bringing in more isopropyl alcohol, other CF cards and (if needed) the logic analyzer into the equation. We'll see what I can find. 

 

Thanks for the help.

[_The Doctor__]

and the other favorite swapping out 74ls08 for the 74f08

[+CharlieChaplin]

It is also possible that the 600XL has XL-OS Rev. 1 and the 800XL has XL-Os Rev. 2. When we tested commercial polish games in the 90s, several of them would not run on a 600XL with 1064 and XL-Os Rev. 1, whereas they worked fine on an 800XL with XL-Os Rev. 2...

[mono]

@CharlieChaplin Could you tell which games didn't work properly? Do you remember? Where is the difference between XL-OS rev.1 and rev.2? I thought there were only bugfixes in new revision (only 1200XL had no new devices IIRC).

Edited April 20, 2023 by mono

[Kaz atarionline.pl]

I can confirm the difference between my 600XL with 1064 module and 800XL/65XE/800XE, which I also have. Just today I checked that the game "DC" on 600XL with 1064 has a very strange difference when use JCart 1MB (from Jakub Husak). One of the sprites on the screen "blinks" when everything is ok on the other computers. The computer is checked by SelfTest and SysInfo (the sprites work properly there). The same program launched not from the cartridge, but from the xex file works fine... 
Does this suggest any differences in handling cartridges?

[Wrathchild]

Yes, data being read from ROM on the cart rather than the computer's RAM for a start.

 

But the PM data itself would be coming from RAM so unless corrupted when being copied there would be harder to track down.

[+CharlieChaplin]

On 4/20/2023 at 11:27 PM, mono said:

@CharlieChaplin Could you tell which games didn't work properly? Do you remember? Where is the difference between XL-OS rev.1 and rev.2? I thought there were only bugfixes in new revision (only 1200XL had no new devices IIRC).

 

I am sorry, but 30 years later I do not remember (which games did not work properly or not at all) anymore. Back then, a friend of mine who published the Top Magazine in Germany (pseudonym Kaisersoft, real name Markus Römer) sold lots of original and copy-protected polish games from LK Avalon, ASF, Mirage and other companies on diskette and some of them did not work at all, some of them did not work properly on his 600XL with 1064 and XL-OS Rev.1, whereas they all worked fine on my 800XL with XL-OS Rev. 2. Think he had approx. 100 different games and approx. 10 did not work at all and another 10-20 did not work properly, but I did not write down the names...

[Stormtrooper of Death]

When I had an 600XL + 1064 mem expansion, I could run the original Big Demo from High-Tech Team. I then had to hack it to make it working. 

the 600XL had a difrent ROM than 800XL/130XE. 

 

fun fact: My hacked Big Demo didnt work on the 800XL/130XE afterwards... = 600XL + 1064 only