AVR-Chat

On Mon, 10 Jul 2006, behrooz_hariri wrote:

> I connected a car battery (12v) to LM7805 to fully minimize power
> supply noise. But still get errors in executing codes.
> I read a film capacitor 0.1uF is necessary after regulator. I used
> electrolyte one 0.15uF.  Does it make difference? 
> 

Electrolytics aren't the best things for bypassing RF.  Since a value of 
0.1 uF or so is meant to keep RF out of the chip's power leads, you might 
do better with a different kind of capacitor.

Make sure you put it as close as you can get to the supply and 
ground pins on the AVR chip.

> I use a breadboard with some wire rather twisted and 10cm long. Is
> this a reason for MCU malfunction?
> 

Possibly. Breadboards are notorious for coupling between 
wires/connections. 

There are quite a few development boards out there that are made to get 
around this problem.

Zack