Mac OS Arduino Problem

[sam123412341234]

I'm having a little bit of trouble with my Arduino. I've been trying to upload my code via Mac but nothing actually occurs in the physical hardware. It says done uploading and anything, but nothing happens. Here's the code that I'm using to see if it will work.

const int YellowPin = 12;

void setup()
{
  pinMode(YellowPin, OUTPUT);
}

void loop()
{
  digitalWrite(YellowPin, HIGH);
  delay(1000);
  digitalWrite(YellowPin, LOW);
  delay(1000);
}

Any ideas as to why it might not work?

[dondonmcgraw]

I'm assuming you have an LED and a resistor attached to pin 12. If you're not sure whether the code is loading properly, and want a "proof of life" I'd either print something to the Serial or run the Blink programme (File>Examples>01.Basics>Blink) and change the rate of blinking for the on-board LED. If the board talks back to you, it's probably something wrong with what you have connected to Pin 12, if not, there's probably a connection problem