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3.3V on the Atmega32u4 breakout board
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3.3V on the Atmega32u4 breakout board

by clearf on Sun Dec 09, 2012 10:59 pm

Hi All,
First time caller, longtime listener.

I'm the recent recipient of an atmega32u4 breakout board. I'm excited to start playing around with it and doing some non-arduino uC programming. I'm was looking to interface it with some 3.3v components, and herein lies my question.

I've been poking around with the schematic trying to follow everything. It looks like the 3.3V labeled on the board is coming out of the UCAP pin on the uC. Looking at the datasheet, it looks like this is provided by a 3.3v internal regulator associated with the USB input.

Here's my question: if I connect Vcc to an external 5V source (and don't run off of USB), what will UCAP be outputting? Does anyone have any insight?

Thanks a lot,
Chris
clearf
 
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Re: 3.3V on the Atmega32u4 breakout board

by adafruit on Tue Dec 11, 2012 10:04 pm

the 3.3v comes only from VUSB so it may not actually be there if you dont plug in usb
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Re: 3.3V on the Atmega32u4 breakout board

by clearf on Wed Dec 12, 2012 11:56 pm

Great, thanks for the heads up.
clearf
 
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