Go Down

Topic: pro mini conversion (Read 829 times) previous topic - next topic

fore4runner

Hi there,

I'm looking to convert a couple of 5v pro mini's to 3.3v pro mini's.  I figure I'll have to swap the regulators, the bootloaders and the oscillators.  I am just wondering if anyone knows the part number for the 8 mHz oscillators as I can't seem to find a compatible one.

Also I think I found something that might work but it's listed as a resonator in digikey.  But what is the difference between a crytal, an oscillator and a resonator (from a google search it looks like and oscialltor is just a crystal with the control capacitors, but I may be wrong).

Cheers,

Andre

CrossRoads

Why? You're just gonna end up damaging them.

Go to gravitech.us and buy 2 more, $17.95 each.

http://www.gravitech.us/arpromi3.html
Designing & building electrical circuits for over 25 years.  Screw Shield for Mega/Due/Uno,  Bobuino with ATMega1284P, & other '328P & '1284P creations & offerings at  my website.

EmilyJane

#2
Aug 24, 2011, 07:41 pm Last Edit: Aug 24, 2011, 08:28 pm by EmilyJane Reason: 1
if you are thinking about reprogramming the boot loader anyway you might take a look at changing the clock prescaler to divide by two. I'm not sure if that will work since I'm not sure the crystal oscillator will run at 16MHz on 3V3 but it's worth a try since it wouldn't require you to pry anything off the board.

Edit: I'd also look into running it off the internal 8MHz RC oscillator. The accuracy is not that bad depending on your application.

fm

The internal clock is a nice option. Depending on the app ofcourse. If you need more precision you can always calibrate it. However, you will end up fluctuating with temperature.

Pros - no moding, change fuses and use an 8Mhz bootloader.
Cons - accuracy, long term stability and temperature drifts.
   

Go Up