Re: [N8VEM: 13963] Re: 68030 SBC project ideas

["J. Alexander Jacocks" <jjac...@mac.com>]

On Sat, Jun 23, 2012 at 4:47 PM, Sergey <skis...@gmail.com> wrote:
> 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

I'd guess that, if we were creating a 68k system, that we'd be
targeting either Linux/m68k or Net/OpenBSD m68k.  And, between the
two, I'd assume that the *BSDs would be easier, given their lack of
assumption that a 68k machine is a Macintosh.

The other 68k OSes out there that I'm familiar with are hp-ux and
SunOS, and they're both _very_ architecture-specific.

I think that a fairly quick 16 Mhz+ 68040 SBC with reasonable RAM
would be very cool.  It'd be quite a hackable system.

And, I second Sergey's suggestion that there be something of a frame
buffer.  It'd be neat to be able to do at least console fonts.

- Alex