[uCsimm] Why was the 68000 bus not exposed

From: Richard Laxton (richardl@chaosmusic.com)
Date: Wed Sep 13 2000 - 11:12:12 EDT

I know that this comes in a bit late but I have only just joined this group
and ordered my uCSimm (awaiting delivery) now.

I have too fairly fundamental questions:
        1. Why was no IDE interface designed into the uCSIMM?
        2. Why was the M68K bus not exposed for use by the experimenter.
When you look at it the IO is pretty pitiful considering the plethora of IO
available at the CPU. This makes retrofitting for Q1. a lot more difficult.

Exposing an 8 bit M68K bus would have fitted on a 72 pin SIMM. Alternatively
everything (and more) could have been exposed on a 168pin SIMM. Sure it
would have been larger but definitely much more functional and useful.

Am I insane or is there a reason why the device was made this way? Don't get
me wrong. The uCSimm as it currently exists is an incredible piece of kit
and something that everyone involved should be proud of. Perhaps what is
needed is a new project group to design a uCSimm Mk II. It could be based
around the newer and faster MC68VZ323.

The new device could have the following integrated peripherals:
        - IDE interface prehaps with DMA support
        - Colour LCD support (built in to the MC68VZ323)
        - Ethernet
        - Full MC68K bus exposed for additional peripherals. This would make
it easy to develop new powerful peripherals such as high speed mutichannel
A/D samplers or whatever.

Constructed as a 168pin SIMM stick would allow suitable expansion on a
similar backplane to the gardener board.

Anyone out there interested in working on such a project or is there
something out there already (in which case I will cancel my uCSimm order and
buy that soemthing else).


Richard Laxton

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