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

Projects General Guidance
1

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

2

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