I've got headers on all of the outputs and inputs
as well as on the
DUT socket, so it's just a matter of jumpering things how you'd like.
With a wirewrap gun, it's literally just a couple of minutes to
change the configuration.
I used the DIN 41612 socket becyuase you can either solder a plug to a
bit of squarepad board and wire-wrap or Verowire the pins together , or
you can stick jumper wires into the holes in the socket. Thr former is
what I do if I think I am going to use that pinout again (e.g. it's fro a
common PROM), the latter is handy for a 1-off (e.g. reading a PAL where
some of the 'output' pins are used as inputs only).
But a uC has a huge advantage when creating a general solution, as
Or a pin-programmable PIA chip (6821. 6522, etc) on the bus of a larger
computer system (as an aside, I hate the 8255...)
you don't need any sort of pin drivers--just
change the programming
for the uC pins and you're all set.
Not so. The problem is the power and ground pins. Not many (if any)
microcontrolelrs can source/sink the current for some of the older
EPROMs. And AFAIK none can output +12V or -5V levels which are needed if
you want to be able to read 2708s and the 3-rail 2716s (that was a design
requirement of my unit, I wanted to back up the firmware in a old Sanders
dot matrix printer).
I was lazy with mine--I knew that counters would work and required no
device programming, leaving the smarts on the PC side.
Indeed. I think I am much like you here. I can wire up TTL and have it
work first time. Programamble logic is less certain :-)