I am trying to integrate an [ADH8066 with an Arduino (I am eventually planning on making my own board using the arduino bootloader on an ATMEGA32U4). The problem is, the ADH8066 uses 4V while the Arduino typically is set up to use 5V. My questions is, can I run an Arduino at 4V 16MHz to avoid using two different voltages on my board? Thanks for any input!](https://www.sparkfun.com/products/10138)
First what board are you using?
The AVR chip can run off of 4V @ 16MHz.
On an Arduino Uno, you have connect your 4V to the 5V pin. Anywhere else, it will go through the 5V regulator. Make sure you the polarity correct because there is no protection on the 5V pin.
Also, you cannot program the Arduino while it’s at 4V. You will have unplug everything and upload your code through USB.
I will be prototyping with a Sparkfun Promicro but hope to build my own board and use the Arduino bootloader on that chip.codlink:
First what board are you using?
You only need a bootloader if you plan to use USB for uploading code (which takes more components). If you use a programmer, you only need to burn the bootloader just to set the fuses. Once you upload a sketch the first time, it overwrites the bootloader.