Simple question about interfacing a GPS IC to an Arduino that is running at 3.3V

Hi Guys,

Just a quick couple of questions:

I am using an Arduino that is running at 3.3V, not 5V. I also have a GPS IC that runs at 3.3V and want to connect it’s RX and TX lines to the Arduino.

The question I wanted to know is this: Because I know the whole circuit is 3.3V, do I need any resistors between the RX line going between the Arduino and GPS, and the same for the TX line? If so, what value, and why would I be doing this?

I’ve heard some people say that the resistors are not necessary if the whole circuit is 3.3V, and I have heard others say they are necessary.

Thanks in advance,
Erik

No resistors are necessary in the case that logic levels are matched. If someone thinks they are required, ask them to explain why.