Atari 800XL; Sio2SD or Uno Cart

[reifsnyderb]

9 minutes ago, E474 said:

One thing I was wondering about was adding in UnoCart detection/support for the ROM in the Compiling a new Atari OS:

 

9 minutes ago, E474 said:

That should, I hope mean better UnoCart support for ATRs as it wouldn't be using a SoftOS, but a ROM image, so the RAM under the OS wouldn't be used. 

 

What needs to be included in the OS to do this?

 

 

[Wrathchild]

I took a look at that, the overheads of the interrupt processing were too much for the ARM to turnaround a response and so the polling is better way.

 

The limitation on ATR size was due to loading the image into the available RAM and actually that could be re-written to support larger files by accessing a sector from within the file on SD card instead. This would help where a larger title is loaded into expanded RAM, including some larger cart conversions.

 

So that leaves the downside to the UNO being not able to use Cartridge images over 128KB.

 

Like E474, time and other projects have kept me away from UNO work but there is loads of potential still for it.

Hopefully a similarly capable but faster ARM will appear that could replace the currently used model.

[flashjazzcat]

I tried to develop replacement UNO Cart firmware which implemented IDE emulation and thus provided direct compatibility with the existing SIDE APT drivers in the U1MB PBI BIOS and SDX SIDE.SYS driver. Got it working but it was a bit hit and miss on different machines owing to the limitations of the bus racing approach. The most difficult part was maintaining a determinate status register state while the MCU was busy reading the SD card.

Edited February 23, 2023 by flashjazzcat

[E474]

2 hours ago, reifsnyderb said:

 

 

What needs to be included in the OS to do this?

 

 

I think, IIRC, the Soft OS got patched to read data from an ATR for Drive #1 on the SD card in the Uno Cart, but to read from attached drives 2-4 if they got accessed. 

The sources are here: https://github.com/e474/UnoCart-Develop/tree/master/source/Atari/UnoCartOS

 

So should include the code to read from a UnoCart, but it should also be in the original repo. I'm afraid I've dropped the ball a bit as it is over a year since I've done anything with them, but the reading from an ATR on the UnoCart's SD card is standard functionality (using the SoftOS).

 

It's a bit too late at night for me to check though, so I will try and look at them some time tomorrow.

 

Quick questions: is the new OS PAL/NTSC specific, if it's good to go for PAL I will try and flash it to my SysCheck II, time permitting (not been following this thread very closely, so sorry for the basic question!)?

[reifsnyderb]

1 hour ago, E474 said:

Quick questions: is the new OS PAL/NTSC specific, if it's good to go for PAL I will try and flash it to my SysCheck II, time permitting (not been following this thread very closely, so sorry for the basic question!)?

The new OS is based on the XL/XE branch, which detects PAL or NTSC and acts accordingly.  There really isn't much that is PAL or NTSC specfic in the OS.

[E474]

Hi @reifsnyderb,

 

   OK, I will try and write it to my SysCheck II card. Btw, I think the UnoCart SoftOS is based on code by @phaeron, so you might have to check with him before "lifting" any code. I posted the comments late last night and should really have pointed that out first. 

[E474]

On 2/22/2023 at 11:33 PM, Wrathchild said:

I took a look at that, the overheads of the interrupt processing were too much for the ARM to turnaround a response and so the polling is better way.

 

The limitation on ATR size was due to loading the image into the available RAM and actually that could be re-written to support larger files by accessing a sector from within the file on SD card instead. This would help where a larger title is loaded into expanded RAM, including some larger cart conversions.

 

So that leaves the downside to the UNO being not able to use Cartridge images over 128KB.

 

Like E474, time and other projects have kept me away from UNO work but there is loads of potential still for it.

Hopefully a similarly capable but faster ARM will appear that could replace the currently used model.

 

Hi @Wrathchild,

 

   I started looking at ARM interrupts but never got anywhere past reading some training material/manuals. I got stuck with FAT File access (the crashing of), which may also be due to interrupt handling problems (due to the way I handled loading ARM files). I still want to get back to trying to get it to work, but don't have the free time at the moment.

 

   Large ATR files (up to 16MB) are handled by the Uno cart, according to the Manual (page 2) : https://github.com/e474/UnoCart-Develop/blob/master/UnoCart_manual.pdf - I'm sure I was accessing 16MB MyDOS ATR images, have you confused this with something else?

 

    Having an OS that supported the Uno that was in ROM, not a RAM based SoftOS should let you run any ATR, but you would need to burn the OS to a ROM as @reifsnyderb is proposing, or write it to a SysCheck 2 card (or some other similar mechanism). 

 

    Actually, you could go the patch-rom route that @HiassofTuses for his hsio code, that might be even simpler for making a burnable ROM image.

 

    Unfortunately I don't have a U1MB, so am missing out on all @flashjazzcat's fancy IDE goodness.

[Wrathchild]

6 hours ago, E474 said:

Large ATR files (up to 16MB) are handled by the Uno cart, ... have you confused this with something else?

Yes, XEX rather than ATR, then you don't need the soft OS.