Here’s a little tip for you; if you’re experimenting with an Arduino and a CurrentCost, trying to see if you can power one from the other and you have the 3.3v pin on the Arduino connected to the unregulated power line on the CurrentCost’s interface port, don’t then have a brain fade and plug the CC128’s PSU back in …
It’s fried something on the Uno with the upshot being that you can’t upload to it on the USB interface – all you get is;
avrdude: stk500_getsync(): not in sync: resp=0x00
I tried the loopback test and that worked okay and I swapped out the ATmega328 to another board and that’s not dead either, so I’m figuring it’s just the ATmega16U2 (that does the USB-to-Serial interface) that got a little bit smokey and isn’t gonna work any more.
Oh well, I can chalk that one up to experience and I’ve still got a semi-working board that I should be able to program remotely, just not over the USB. I’ll have to have a hunt round to see if anyone’s written a diagnostic sketch that checks out what is/isn’t working as expected on an Uno.