Member #463530

Member Since: August 21, 2013

Country: United States

  • Hmmm, If I plug USB cable in this board I get 5V, so everything’s ok with that. But on the board there is a SJ1 jumper that allows to change chip’s supply from 5 to 3.3V. If I choose to drive it at 3.3V than the pin configuration on this board is different than what specs recommend. I made a PCB containing Atmega32u4 + some other sensors and followed this schematics, all at 3.3V and didn’t get it to work. After switching to 5V, everything was fine. My first assumption was pin configuration fail. Did you have experience with successful 3.3V/16MHz/this pin configuration combo?

  • Hi, I checked in the datasheet and saw that you need different configuration of pins VCC AVCC, UCAP and UVCC for 3.3V power supply and 5V power supply (section 21). However, on your board they are the same. Also you have only one quartz oscillator on board (16 MHz) which is not suited for 3.3 volts. Does the device work properly at 3.3V? If yes, how is it possible?

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