Re: 68030 SBC project ideas

[Sergey <skis...@gmail.com>]

It sounds like an interesting idea. I am not very familiar with
Motorola 68K family, but it looks that 68040 is a better fit,
especially for running Linux (I guess FPU can be emulated... it can be
on x86, but it will be very slow). Also as some mentioned it appears
to be more available than 68030.

Other notes:
- Propeller is pretty easy I/O solution. The downside is that it will
be difficult to implement a frame buffer with it. Can we use some
"true" frame buffer chip instead?
- RAM/SIMM - it will require a DRAM refresh circuit, hopefully there
is a suitable and easily obtainable DRAM controller for it.
- If high clock is a concern, I guess the CPU can be underclocked. Or
we can go for 4-layer PCB (which will increase the cost, but still
should be something manageable about $40 or so).

I personally was thinking some time ago to build a 386EX based SBC
system, with the same intention of running Linux. Specs are something
like:
- 386EX CPU (includes timers, interrupt controller, DMA, etc.) Most of
these devices are PC-compatible (DMA has limited compatibility).
- Cirrus Logic CL-GD542x graphics (it has a mode that supports 386
local bus, which is much faster than ISA).
- USB controller - this will allow connecting all other peripherals
(storage, keyboard, mouse), etc.
- DRAM (386EX includes DRAM refresh interface logic)
- Some flash memory for diagnostics/boot ROM.

The advantage is that this configuration will be easily supported with
Linux.
The disadvantage is that most core components are in flat-pack
packages, which might be difficult to work with.

Thanks,
Sergey