westfw:
Does it behave the same if you power it up by connecting via USB?(In theory, the bootloader only runs when the reset status register identifies the reset cause as "external reset." "Power-on reset" is supposed to be a separate cause, which should not cause the bootloader to run.)
Yes, either way (via external reset button or power-up via DC plug or power-up via USB) the boot loader runs. And by "runs" I mean it flashes the LED 3 times and continues into the optiboot loop. Not just hit the check for EXTRF and jump to appStart(). So, it's not performing as the optiboot source code implies. It's not doing the "no-wait" on power-up.
Not that it's a big deal. Just trying to understand what I have. And I don't understand it yet. Unless, there is some sort of UNO board circuitry that asserts an external reset on power-up.
Does anyone else see this behavior with a new UNO (R3)?
TheGipp