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Topic: Odd behavior from bootloaded ATMega328 (Read 1 time) previous topic - next topic

fotoflojoe

Apologies if this is the wrong forum for this question, but it seems the most appropriate.

After building a circuit and writing a sketch to drive three panel meters, I'm seeing odd behavior when I remove the ATMega328 from my Duemilanove, and place it directly into the circuit.

I've based my Breadboarded circuit on this tutorial:
http://arduino.cc/en/Tutorial/ArduinoToBreadboard

The sketch basically does continuous analogWrites to pins 9, 6, and 5.
When the circuit runs directly from the Arduino board, everything is fine and stable.
However, when the circuit is transplanted to a breadboard, I'm seeing "noise" in pins 6 and 5.
I've checked and double checked my connections and don't see any problems - it's driving me batty!

Of course, I'm at work right now and don't have my sketch code or pictures of the circuit to post!
(How's that for asking for something based on nothing?  :P)
I will post them as soon as I'm back at my own computer.

The environment is Ubuntu Linux 10.04, running Arduino 0018 (pre Uno).

Thanks in advance for any help!

fotoflojoe

Problem found and solved: Old defective Breadboard.

liudr

Thanks for sharing the cause of your problem. What kind of defect are you referring to? Short circuits? I'd like to know so I can spot the same problem in the future.

James C4S

Quote
The sketch basically does continuous analogWrites to pins 9, 6, and 5.
When the circuit runs directly from the Arduino board, everything is fine and stable.
However, when the circuit is transplanted to a breadboard, I'm seeing "noise" in pins 6 and 5.


Did you write the sketch to continuously do analogWrites?  What would those even look like?  If you analogWrite the same value twice, nothing changes.  It sounds more like you are seeing noise introduced by the breadboard environment.

Have you tried adding additional decoupling capacitors to your power supplies (and the VCC pins of the ATmega?)
Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com

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