Re: Further (mis)adventures in shoddy soldering…

Posted by Pilkerton on Jul 28, 2016; 10:22pm
URL: http://bluesaab-forum.90.s1.nabble.com/Further-mis-adventures-in-shoddy-soldering-tp559p576.html

tldr; a 3.3v Atmega might be marginal at 16Mhz

So just when I thought things were stable again, this morning my BlueSaab device was nowhere to be found. Thinking about hsl’s similar experiences, plus other mysterious reboot behavior Karlis mentioned, I wondered if the tolerance of the resonators could possibly be at issue, which led me to this informative stack exchange thread.

Please double-check this, but it looks like the Atmega is being operated out of spec. Here’s a screen from the “Speed Grades” page of the Atmega datasheet:



While the general consensus seems to be "3.3v @ 16Mhz works for me, YMMV", this quora post offers the following advice:

The one issue you might run into is that at 3.3V you're much closer to hitting the brownout detector, which will reset the controller if you fall below about 2.7V. If this is a concern you can change the settings for that.