Standalone ATMega328 and 3.3v Requirement

Hi all,

I am currently designing my own pcb for use on my high altitude balloon flights - simply to reduce the mass of wires that I currently have! However I have come across a problem. I will primarily run the atmega328 chip at 5v (via reg etc) at 16mhz. This is fine for the majority of my components however the gps module I am using (uBlox 6) requires vcc at 3v3 and serial comms at 3v3. What is the best way of going about this?

Currently I am thinking: 1) use a 3v3 regulator feeding off the 5v supply from arduino to power the gps module 2) use a potential divider to drop the 5v serial to 3v3 for the serial comms to gps module

Would this work? Are there any nasties involved with hooking 3v3 reg up to my 5v arduino supply/will I need extra capacitors?

Many thanks in advance :)

The extra regulator will need its own capacitors.

Using a simple /2 voltage divider (two equal resistors of about 10K) works well for 5V outputs to 3.3V inputs. Nothing special is needed for 3.3V outputs going to 5V inputs.