[Coco] CoCo3 MMU Register question...

[Zippster]

I have a scheme in mind, using a CPLD for address decoding, and high speed latches
for the MMU bank registers, that would operate similarly to one set of CoCo3 MMU banks.

With 8 banks (0-7), the same register locations in memory as the first instance in the CoCo3 (TR 0).
Using each memory location ($FFA0 - $FFA7) to hold an 8-bit value for the memory block to map to (in a latch).

Perhaps someone who knows about OS9 can tell me if a simplified MMU scheme like this would be
suitable to compile OS9 to use.  This is without a second task register, and no ability to read the MMU registers.
Those things could be implemented if necessary, but trying to keep it simple.

Any thoughts or suggestions?  Unfortunately I don’t know squat about OS9’s memory usage.

- Ed


> On Mar 30, 2015, at 1:22 PM, Joe Grubbs <jsgrubbs at hotmail.com> wrote:
> 
> I wish I could help because this sounds like a great project, but I don't know enough about my Coco3 to get this information.
> 
> 
> 
> --- Original Message ---
> 
> From: "Zippster" <zippster278 at gmail.com>
> Sent: March 30, 2015 9:03 AM
> To: "CoCoList for Color Computer Enthusiasts" <coco at maltedmedia.com>
> Subject: [Coco] CoCo3 MMU Register question...
> 
> Hi guys,
> 
> Can anyone tell me what the default state (on power-up) is as far as the
> values in the MMU registers in the CoCo3?
> 
> Any information on how they are initialized/configured on startup would be appreciated.
> 
> Working on a 2meg RAM upgrade for the CoCo2, and I want it to mimic CoCo3 RAM handling
> as closely as possible.
> 
> Thanks,
> 
> - Ed