Digital output voltage/current

Other Hardware General Electronics
1

In starting to play with my new Arduino Uno, I played with the blink program varying the pin used to output.

I have found that digital output pin 12 seems to provide enough voltage (or current if others are current limited) to power several LEDs fairly brightly, but all other pins I've tried turn the led's on very weakly. Using a 330 ohm current limiting resistor.

Are the pins meant to have the same voltage and current supply capability?

Thanks for any help

2

All pins have the same current handling capacity, and a HIGH output is Vcc (5v on a normal Uno).

My guess is you have forgotten to set the pin to OUTPUT with pinMode(), so you're just turning on the pullup resistors, so you get practically no current through the LED.

3

Thanks, exactly the problem.

Always run into something like this when I grab someone else's code in a language/env I'm unfamiliar and start to modify it.

Thanks again