Reflash Nano V3 if prior sketch uses serial

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3

Take these steps:

  1. Power off the board completely
  2. Remove the USB cable
  3. Hold down the Reset button
  4. keep it held down (or, run a jumper wire from the RESET pin to the GND pin).
  5. Still holding down Reset reconnect the USB cable.
  6. Start uploading a sketch that does not have this problem (I use the Blink sketch).
  7. When you see the Receive light blink, release the Reset button
  8. Change your code and add a delay(3000), or more in setup(). This allows easy recovery from a serial flood.
    Note: I have seen this happen several times when I flood the serial output. An indication is the TX light is stuck on.