Seeking Local Help with WP34s

[mfleming]

Boy, my face is red! Sorry for the unnecessary jargon. Barry is right, I did intend to suggest powering the calculator from the same source as the serial interface signals. Doing so would insure you did not inadvertently exceed the voltage rating on the processor pins due to low battery voltage (documented in an earlier thread somewhere). I use a small USB to serial breakout board that provides the 3.3V power in my own programming setup.

As an interesting sidenote, I've most always seen voltage supplies referred to as "rails" as in my "3.3V rail" reference. Or when referring to an amplifier whose output can swing all the way from the positive to the negative supply levels as having "rail to rail" output. I'm not really sure of the origin of the term rail (could it be an Americanism?), but I would not be surprised if it dates back to early electrical wiring practices, such as with relay ladder logic. I'd love to see someone chime in with a little history of electrical/electronic terminology

~Mark