[Coco] Fwd: Commodore PET 8032 add-on SuperPET2 board.
Boisy G. Pitre
coco at toughmac.com
Mon Feb 22 14:54:51 EST 2016
Here’s a great opportunity for someone to help with a port of NitrOS-9 Level 2 to a new MMU board for the SuperPET. I’ve forwarded Dave’s email with his permission.
Boisy G. Pitre
CoCo Projects Coordinator
> Begin forwarded message:
> From: davee.roberts at fsmail.net
> Subject: Commodore PET 8032 add-on SuperPET2 board.
> Date: February 21, 2016 at 2:52:21 PM CST
> To: boisy.pitre at affectiva.com
> Reply-To: davee.roberts at fsmail.net
> It's a while since we exchanged e-mails.
> I have now completed the schematic for my add-on SuperPET2 board for a Commodore 8032 - and my mind is now turning to the PCB layout itself.
> I have thought about the memory mapping and have decided to incorporate an SN74LS610 dedicated MMU. I have outlined my proposed scheme at
> I tried last week to get my head around the NitrOS-9 source code - but failed dismally. I will have another look when I have some more time.
> If you are still interested in porting NitrOS-9 to my SuperPET2 add-on board could I ask that you take a look at what I am proposing to see if it is vaguely sensible? My scheme
> involves using 4K pages (instead of 8K on the CoCo 3) and I have the ability to map the standard PET memory, screen and I/O page around as I wish - with the proviso that the I/O
> page ($0EXXX) is mapped somewhere available to the CPU (otherwise we can't control the MMU ever again as we can't get to the I/O page).
> If you are not interested - would you be able to answer a few questions regarding porting NitrOS-9 when I get the hardware working and I turn to the software?
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