Dave Mills wrote: [...]
I've just given this version a try - no joy though. It just sits there "Waiting for device reset..."
I am trying to talk to a fresh out of the box E2 with a simple zener diode voltage limiter serial cable. One thing that might be causing problems is my USB>RS232 converter - I shall have to find a laptop with a real serial port to try again.
Don't forget that the protocol requires the E2 to talk back. RS232 is
+3V for logic 0, <-3V for logic 1, and the E2 expects TTL voltages with
0V for logic 0 and 5V for logic 1 --- so the sense is inverted with respect to RS232. I don't think you can convert in both directions with a simple voltage limiter.
I used a hacked mobile phone cable --- details on my website. I don't think that specific model's in production any more, but once you know what to look for RS232-TTL converters are reasonably easy to come by.