For some reason the Arduino IDE is unable to see my Arduino Uno even though it is connected. I have reinstalled the Arduino software, but no luck come of it. I connected the Arduino to my friends mac, who's could see it.. I am very confused and greatly appreciate any help.
Thanks, Shaun
I ran into a similar problem years ago on an ATMega128 (before Arduino) and you just have to be aware of alternative functions for the port. In this case PD0 is Hardware Serial RX which is a receive pin.
Here's some relatively older code based around the same idea:
Yes, you can use the RX/TX pins as regular IO. Just don't call the Serial.begin() in your code, and make sure you call a pinMode() for them.
Another interesting post, fourth post: http://www.nerdkits.com/forum/thread/536/ where they disable the serial functionality once the code begins, downside (a above) you will lose serial comms, so it depends on how much you need them.
UCSR0B = 0; I'm not sure how successful that would be in today's arduino, I know a lot (if not all) of the prior functionality is maintained, but I haven't used them in a long while.
The pin should become active again as the bootloader will automatically reenable it upon reset (although I haven't personally tested it). It will just make debugging that little bit harder if you need to.
As I mentioned in my comment, if you have another pin available to you, use that instead.
In case someone else has this problem..
Turns out, you can't be connect to pin D0 whilst using serial.
