Hi Everyone!
I have been searching around on the internet but I can't find anything relating to my problem. I think something is wrong with Pin 3 on my Arduino because it is always showing 4.3v - 5v (my meter isn't very accurate). I had changed the TCCR2B so that I would be able to get a higher frequency PWM from it and it worked fine last night. After plugging it in this morning it was stuck with the current voltage on it. Even trying to set pin three to digital input mode does nothing, it still puts out ~5v. Pin 11 works fine at both 500 and 32khz frequencies. Is my AT328 fried or some other part of my board? Is there any way to get Pin 3 working again that doesn't require changing the AT328 or some other on board component? I tested all of the other digital pins and PWM functions on the other 5 pins using a LED and a blink and dimming program.
Any help or insights would be appreciated.
Thank you.
Check for any shorts like a piece of wire stuck somewhere shorting things out.
If there is nothing physically obvious, I'd say you'll be swapping the chip.
Hey BRuTus!
Thanks for the reply. I don't know how I could miss a wire and the traces look fine as far as I can see. How much back voltage can the PWM pins take and would too much be something that could lock them open?
On a side note, I lived in Calgary for 19 years and went to Lord Beaverbrook HS.
Thanks for the help!
I'm not 100% sure on the back-voltage thing, but I know I killed one with some static.
Mine was completely my fault. (Grabbed the board after getting up from a fleece blanket)
Afterwards, the rest of the chip was fine, but analog 4 always returned 1023 as a value, it was definatly 'hooped'.
I would guess your internal pullup resistor is stuck on, giving you the constant voltage. Hopefully you are just using Duemilanove or Freeduino with Changeable IC.
You can get a new one here in Calgary HERE, but depending on where you live now, that may or may not work for you.
How much back voltage can the PWM pins take and would too much be something that could lock them open?
It can take about -0.5V before you get damage.
Thanks Mike and Brutus! I am pretty sure the back voltage is what happened. I was using the Duemilanove to control 2 l298n's and 2 stepper motors. I had the power unhooked and was twisting the stepper motor shafts back an forth (I wasn't thinking) and I started to feel some resistance and thought the motors were breaking (again not really thinking). After that, I hooked everything up again and my previously working circuit wasn't working any more. I might have done something to the 298's as well but hopefully its just the AT328. I can drive the circuit using pin 11 but when the motor is holding I can feel that the signal is noisy (vibrations in the shaft that were not there previously). I have a replacement AT328 on the way. I live in Phoenix AZ now but thanks for the link Brutus.
Cheers!