3 Apr
2014
3 Apr
'14
2:57 p.m.
Ethan said:
I'm sure original Ethernet cards are rare - is
there anything on it
that might take a bit of work to reproduce?? PALs, for example.? I've
worked with a couple of vintage machines with AMD 7990s and the media
end of things is rather straightforward.? On the host side, there's
usually address decode logic, a bus interface (unless it plugs into a
processor socket like some add-ons did), and often a boot ROM.? I ask
because some day, I'd like to get a 3B1 and I'm expecting it won't
come with Ethernet.
The technical manual has a pretty thorough description and
a schematic.? At first glance, there appear to be 5 PALs, but
nothing fully custom.? Most of the PALs are registered, but they
are mostly used for a state machine and the documentation
includes timing diagrams that look like they'd go a long way
toward reproducing the equations.? My copy isn't very good,
but I don't see the equations listed explicitly anywhere.
BLS