9 Jun
2005
9 Jun
'05
5:23 p.m.
On Fri, 2005-06-10 at 00:09 +0100, Tony Duell wrote:
Yep, Q2, Q5, and /NMISW
(Q0 drives the reset inputs for the keyboard's on-board counter, whilst
Q1 provides its clock pulses)
cheers
Jules
Alas I don't have a Nascom 1 schematic...
Well the Nascom 1 *keyboard* schematic is online on a Nascom site along
with the rest of the schematics for the Nascom *2*. Which does seem a
bit strange, as though maybe the keyboard schematic for the Nascom 2
isn't part of the standard documentation.
Not that there appears to be much difference between the two; the Nascom
2 one just has the extra row (and no doubt totally different key matrix)
and this keyboard sense line (which as you say probably isn't used by
the software anyway).
In all it uses
13 out of the 16 pins on the keyboard PCB. Pins between
the keyboard and CPU board *do* match up 1-1, it's just a case of
WHich 3 signals are not used? I would guess at Q2 and Q5 and one other.