24 Feb
2013
24 Feb
'13
12:06 p.m.
We've had some success decoding the various LSI chips found within the
IBM Displaywriter System, in this case the external 8-inch floppy
drive subsystem (IBM 6360), but one last chip has stumped us, or more
accurately stumped our Estonian colleague who was familiar with the
IBM to Intel part number mapping, see here:
http://www.cpu-world.com/forum/viewtopic.php?p=164045#164045
Anyone with knowledge of how to implement the NEC D765D floppy disk
controller in a detached setup might be able to make a good guess as
to the function of the remaining 40-pin DIP IC (labelled 4430030) in
the picture?
http://i.imgur.com/VtMxSqj.jpg
is it another peripheral chip or perhaps a CPU? I'm guessing the
former since I don't see anything that might hold ROM code for a CPU.
It could be a microcontrolelr woth internal firmware store. Maybe a
8041/8741/8042/8742 -- the Intel 8048-derivatives that contain a couple
of interface registers so you can use them as a complex peripeheral
interface on anotehr CPU's bus.
Hav eyou treid tracing out any of the conenctions? At least power and
ground. Maybe data buses, clock, reset, etc. Often knowing some of those
will narrow the possibilties right down.
-tony
