Subject: keyboard pinout?
To: None <>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: port-next68k
Date: 10/16/2001 19:21:02
This is really a hardware question, but (a) it's in aid of NetBSD work
and (b) this is the best pool of NeXT expertise I know of. :-)

I have a Slab that I'm using to work on porting X11R6.4 to, as I
threate^Wpromised a while ago.  Much of the time I don't need the
monitor, and as I have only the one I then want to leave it off.  So
I've been running it headless.  I find that provided the kernel uses
the builtin display and keyboard for console, everything works except I
can't see the output (and of course can't type input).

However, I want to be able to use the CMD-ALT-* nerve pinch to reset
the machine, instead of having to unplug it and then use the 470-ohm
resistor on the power line method to turn it back on.

Is it feasiable to build a passive adapter that connects keyboard to
slab without needing a monitor in between?  Or are there too many
smarts in the monitor?  I do note that the monitor pinout does not
include a "hard reset" line, which was what I first expected - I assume
there's an ASIC on the CPU board that watches for the nerve pinch and
kicks the CPU when it occurs.

I've cut a spare monitor cable in two; that's how I built my 470-ohm
power-on doohickey.  I'd be prepared to cut the connector off a
keyboard cable in aid of this, if necessary - but if more than level
shifters would be needed, it's probably not worth doing.  And I've
never seen a pinout for the keyboard cable.  I would guess that it ends
up on the MON DATA IN pin on the DB-19, since (a) I can't see why the
monitor itself would want to send anything back and (b) I can't see any
other pin that looks like input to the CPU....

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