Strange modded 800XL’s

[fred]

I picked up a couple of 800XL’s. They have some strange mods. Anyone know what they are for? 
 

One computer has pok.54018,53 written on it. It also came with the Basic cartridge. Is there any difference between this and regular basic?

 

My main 8 bit is an XEGS, so I have no idea about these. I’ll probably post these for sale after I test them and learn some more about them

[Beeblebrox]

Likely Ram and switchable dual OS mods. Intrigued about all the mystery buttons. Ctrl and in particular the little non descript black button.

 

Best thing is open them up and snap some pics to upload. 

[_The Doctor__]

@fred

POKE 54018,53 is Port A control, it may be setting an irq and control line possibly cassette motor control.

the one Atari has a Rambo memory upgrade, switches may turn the upgrade on or off, you may have a hard reset line as well.

You may have a dual OS in the other or an internal basic defeat switch.

carefully looking inside might refine this further, just make sure not to hurt the spaghetti inside, some xl's don't like their ribbon cables disturbed. careful not to flex or disturb it too much when pulling it apart. lift more on the left of the cover than the right.

If you are brave enough to open it.

 

It should be trivial to just try the switches and use a memory test program to check what's what. There are a few sysinfo and detect proggies on the forums here.

 

It will be pretty obvious what you have by flipping a switch then powering up and observing what you see and test.

You can perform that poke with switches in different positions as well.

 

Not that big a deal really, it's very standard stuff for a time when we hacked whatever we wanted in our machines

Edited December 21, 2022 by _The Doctor__

[TGB1718]

I would guess the "Option" will enable/disable BASIC so you don't have to press OPTION during boot

if BASIC is not required.

 

The Cart is BASIC XL which is compatible with Atari Basic in as much as it will load and run standard

BASIC programs, but it has some nice extensions, so anything written using these new extensions would

not work with standard BASIC.

 

It also runs much quicker than Atari BASIC

Edited December 21, 2022 by TGB1718

[Thelen]

11 hours ago, _The Doctor__ said:

POKE 54018,53

Yes, that is to put the cassette motor on - you can listen audio tapes with this poke command.

[fred]

1 hour ago, Thelen said:

Yes, that is to put the cassette motor on - you can listen audio tapes with this poke command.

Very cool, so you can play an audio tape, enter that command and listen to it?

[_The Doctor__]

Yes and many us did just that. Others used it to control relays and such as well. Search and you will find much more than just these links below...

https://www.atarimagazines.com/v5n8/StepperMotorRobotControl.html

https://forums.atariage.com/blogs/entry/11626-relay-boards-under-atari-8bit-control/

https://www.atariarchives.org/creativeatari/Interfacing_Your_Atari.php

 

I am always helping folks find a rabbit hole full of fun