[Coco] MC6829 Memory Management Unit

[Walter ZAMBOTTI]

 From what I can tell from the my brief reading of the manual the device 
works in a similar way to the GIME MMU except

it supports up to 2 megabytes,  2K block sizes and 4 tasks.

           Max Mem  Block Size Tasks

GIME       512MB     8K           2

6829     2048MB     2K           4


The smaller 2K block size makes that quite attractive.

However since OS9 is written for 8x8k pages the MMU register structure 
would need to be enlarged to cater for 32x2k, if it is not already reserved.


On 7/10/22 20:02, Mathew Boytim via Coco wrote:
>   Wow that's an interesting story.  I have no idea about the app note though.
> Thanks,
> Matt
>      On Friday, October 7, 2022 at 06:28:24 AM EDT, Carlos Camacho via Coco <coco at maltedmedia.com> wrote:
>   
>   Long ago, I remember seeing a Motorola application note with the MC6829
> Memory Management Unit. I looked for it on eBay and other sources but
> couldn't find it. I was told that Motorola never released it.
>
> Fast forward to two weeks ago when someone posted a European seller on eBay
> was selling them. Probably counterfeit Chinese goods I thought. I reached
> out to the seller and he explained that he obtained them from a German
> factory that was liquidating their IC inventory. That sounded promising so
> I bought his entire stock of MC6829 Memory Management Unit.
>
> It's on its way to me. I'll need to find that app note and build the
> circuit board to confirm they are indeed the real deal. Any other advice?
>
> Cheers,
>
> Carlos Camacho
> CoCo Store
>