Re: //c keyboard matrix pinout

[Michael Black <et472@ncf.ca>]

On Wed, 19 Sep 2012, option8 wrote:

> In working on an Apple to USB interface, I've found this document very useful for pinouts of various Apple II components:
> http://mirrors.apple2.org.za/apple.cabi.net/FAQs.and.INFO/CablesAndPinouts/A2.MISC.PINOUTS.TXT
>
> most notably the IIe keyboard matrix.
>
> I've worked out most of the matrix for the IIc with a multimeter and trial and error, but I've got a few weird overlaps. I wonder if there's a document anywhere that has the full pinout for the IIc (and maybe IIgs as well).
>
> Any pointers?
Have you tried the original Apple II keyboard layout?

I once traced out the power supply on the Mac Plus, doing it literally, 
and once that was done of course it didn't make sense since I was drawing 
to match the layout while a schematic is drawn for readability, having a 
logical path to it from left to right.

For some reason I looked at the schematic for the Apple II, and it looked 
a whole lot like the Mac Plus supply.  Using the Apple II schematic as a 
template, I then recopied the circuit I'd traced out into the same form as 
the Apple II schematic.  I can't remember how much or little it differed, 
but it was quite similar.

Given that, if I was tracing a later keyboard, matrix, I'd use the earlier 
one, seeing if it matched.  It can be easier to "prove" that a circuit 
matches an existing schematic than try to simply trace it all from 
scratch.  It might differ, I don't know, but I can see them recycling.

  Michael