Hi all
Well the MK14 from martin is up and running.
And thanks to the information supplied about a MK14 programming interface I built an interface board and it can now program the MK14. It is in 2 sections. The optical switches to connect to the MK14 and a separate board for the Pi Zero w. The reset is solder to the underside of the board and connects via a 2 pin plug.
I did have a couple of issues with one of the optical switches not working correctly. I think the problem seems to be that using 3.3v and 330r resistors one of the them was not getting enough juice to turn on. It worked when I tested it, before building the Pi interface, and the test system was nearer 5v. Think I'll use the 5v from the Pi to power the optical switches.
The other issue was speed. as was mentioned in the MK14 programming interface thread I had to slow the interface program down a bit to get reliable results.
But it's so much faster than having to type it in
Now to look at using an Arduino for the controller - problem with the Pi is it needs to be shutdown correctly where as an Arduino can just be turned off.
David