14 Oct
2010
14 Oct
'10
11:18 a.m.
On 10/14/10, Dave McGuire <mcguire at neurotica.com> wrote:
Ah... hadn't considered that arrangement. If that's true (I can't
check myself), then that method is untenable (well... one could blow a
hole in the case bottom and put the machine up on pegs...) I was more
expecting that the CPU was under the PSU or the drive bay or otherwise
cramped from the top.
OK... next idea... a MC68010L-sized PCB with room for a MC68010FN
(http://www.cpu-world.com/CPUs/68010/Motorola-MC68010FN10.html) and an
SMT 5380. Sort of a "no slot clock" kinda of arrangement (same
footprint, but perhaps only slightly thicker). The next most
difficult thing to do would be to figure out how to get the SCSI
signals off the board. Probably have to be a multi-layer board to get
all the signals to all the right pins. The bonus would be that it
would likely work in many, many MC68K machines (depending on the
orientation of the off-board SCSI pins).
-ethan
On 10/14/10 1:43 PM, Ethan Dicks wrote:
Yeah... well... even so, the 5380, while trivial to hang off of a CPU,
is not known for performance. Without a DMA engine, it might not be
worth involving the 33C93 (for which there are probably fewer driver
examples to borrow from).
On 10/14/10, Eric Smith<eric at
brouhaha.com> wrote:
Compared to the WD1010-based MFM controller it'd be replacing? ;) Years ago I wire-wrapped a card with a 5380 SCSI
chip.
That would be when I would start - and maybe consider a WD33C93 (as
found in the Amiga 3000) if the performance of the 5380 turned out to
be an issue. Perhaps a
CPU-socket design is worth considering. 64 pin DIP sockets
are still available. ;-)
The main board of a 7300/3B1 is on the bottom of the machine, and my
very vague memory from 20+ years ago says it might actually be
component-side down. If this is actually the case, it'd likely be too
tight in there for such a daughterboard.