Go Down

Topic: Breadboarding atmega328 yields unexpected behavior (newb needs help) (Read 1 time) previous topic - next topic

justanotherhumanoid

#5
Jan 21, 2013, 05:41 am Last Edit: Jan 21, 2013, 05:52 am by justanotherhumanoid Reason: 1
Okay, made the recommended changes (reset to +5v via 10kOhm resistor and putting resistor in series with LED) and attached new pic. I thought the crystal was hooked up properly, though - I've got the crystal across X1-X2, then a 22pF cap to ground from X1 and X2 as well. Is that incorrect? Should be able to see what I'm talking about in the new photo. How should this be hooked up if that's what I did wrong?

Still getting the same behavior - LED stays lit up and never blinks. Thoughts?


Jack Christensen

You're not understanding how breadboards connect things, you've made the same mistake with the LED current-limiting resistor as you did earlier with the reset pullup resistor, putting both leads in the same row does absolutely nothing, the resistor is not even in the circuit that way.

Pull out the two black wires that go from the X1 and X2 pins to ground and report back!
MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

vasquo


Okay, made the recommended changes (reset to +5v via 10kOhm resistor and putting resistor in series with LED) and attached new pic. I thought the crystal was hooked up properly, though - I've got the crystal across X1-X2, then a 22pF cap to ground from X1 and X2 as well. Is that incorrect? Should be able to see what I'm talking about in the new photo. How should this be hooked up if that's what I did wrong?

Still getting the same behavior - LED stays lit up and never blinks. Thoughts?

Yikes... here's what, unhook everything, then get a multimeter and get familiar with the internal connections of your breadboard. See which set of holes are connected to one another. -- then you'll see how you currently wired your breadboard doesn't make sense.

You're basically treating it's holes as holes of a PCB, and you expect it to read your mind.

Jack Christensen

Suggest reading through this and building the simple LED-and-resistor circuit:
http://www.sciencebuddies.org/science-fair-projects/project_ideas/Elec_primer-simplecircuit.shtml#summary

Your 5V supply will work fine, in fact probably preferable to use that rather than a 9V battery.

Resistor value is not critical, anything between 220 ohms and 1000 ohms will be fine, the LED may not be real bright with 1000 ohms.
MCP79411/12 RTC ... "One Million Ohms" ATtiny kit ... available at http://www.tindie.com/stores/JChristensen/

justanotherhumanoid

#9
Jan 21, 2013, 06:11 am Last Edit: Jan 21, 2013, 06:12 am by justanotherhumanoid Reason: 1
Jack, fellas, thanks for the fast responses, solved in record time! It's blinking away happily. It was definitely due to the incorrect wiring, stemming from my lack of understanding of breadboard connections. In retrospect, the way I had things hooked up really didn't make sense, and I'm lucky I didn't cook anything.

Thanks again so much for the help. Have a good night, and rock on.

Go Up