[Coco] 6 Chip ^809 Computer -> Kipper SBC

[Aaron Wolfe]

On Wed, Mar 11, 2015 at 2:29 AM, Bill Nobel <b_nobel at hotmail.com> wrote:
> Hi Kip is a/the MMU going to be after the Kipper bus or will it eventually be embedded on the main board?  I have come across a MMU circuit (similar to a 74LS612 type MMU) that will map up to 16MB of memory on a 8 bit bus, using off shelf parts.  I’m still interpreting the logic, but I was wondering the future plan for the bus.  It currently adds 10 chips to the board for the 128 MMU registers, but needs a bit more addressing logic for the mapping of the extra 8 address lines to the 6809/6309.  I think the logic does 64k pages from what I deciphered so far.
>
> I am incorporating your Kipper bus onto my own design (combined with parts of Simons board) that will contain the MMU once I complete the breadboarding.
>
> This MMU I will state IS NOT compatible with the Gime in Coco3, but gives an alternative for more RAM on the SBC.
>
> Bill Nobel
>

Before going too far with things like an MMU, you may want to consider
striving for compatibility with the N8VEM 6809 single board computer.
This is currently in production and has a decently sized group
developing software for it.  I know FLEX is available and a project to
port OS9 is/was in the works.  Using a similar MMU, memory map, etc
might make using the efforts they have made practical.

http://n8vem-sbc.pbworks.com/w/page/82119161/ECB%206x0x-ATX-6U#Introduction

-Aaron