I am playing around with the Sparkfun Venus GPS. I followed this tutorial to get started. In here the author states that you should

Upload the following sketch to your Arduino BEFORE making any connections. 5V from an IO pin left high on the Arduino may well kill the 3.3V output from the Tx pin on the GPS module.

However, I am using the Sparkfun bi-directional logic level converter in between the Arduino and the Venus GPS (because I'm using the 5V Arduino GSM shield stacked on top of the Arduino). In that case, would the above statement still apply?

1 Answer 1


If you have a logic-converter between the Arduino and the GPS then you won't have any problems.

The warning was about having the output from the Tx pin on the GPS possibly being damaged by +5 V from the Arduino, if a previously loaded sketch made it an output and HIGH.

However you could just as easily upload a "do nothing" sketch like this:

int main () { }

That is sound practice anyway, if you are connecting up new hardware and are not sure what the currently-loaded sketch does.

  • I've been running it without any issues with a logic converter for a while now. Thanks for the tip on the do nothing sketch though. Commented Aug 26, 2015 at 4:02

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