COMBOARD (MC68000) hardware hacking (was Re: Solderless breadboarding)

[Ethan Dicks]

On 2/18/10, Henk Gooijen <henk.gooijen at hotmail.com> wrote:
> I have no experience with SCSI chips...

No harder to wire up than a UART or PIA/VIA, but the rest is all
software to create/interpret the SCSI packets.

> but the software to read and write a sector of an IDE disk is simple enough.

I've written low-level driver code for IDE manipulation on a GG2 Bus+
equipped Amiga.

> A TTL-based interface would
> take not much time. 16 bit data (may need buffering) and a few address
> decoding gates is probably all you need to hook up an IDE drive.

Address decoding gates might not even be required - I have full
schematics for this board (I used to make them commercially) and have
the PAL equations for the memory map PALs.

I think it could be as easy as buffers and a PAL swap (plus software).
 I just flip-flop between SCSI and IDE and never get started.

-ethan