Pin 1 goes high for a few ms for no reason (that I understand)

Development Tools IDE 1.x
1

I am an Arduino virgin, so please be gentle.

I bought a brand new, Uno Genuino on eBay. To get started, I created a simple sketch that pulses 10 LEDs in sequence. It works as I expected except that when pin 0 goes high, pin 1 also goes high but for less than a second, then low. I confirmed this with a voltmeter.

This is freaking me out because I bought another brand new genuine Arduino Uno and it’s doing exactly the same. Are both of these boards defective? Am I defective??

void loop() {
for (inner = 0; inner < 9; inner++) {

digitalWrite(inner, HIGH);
delay(5000);
digitalWrite(inner, LOW);
}

What am I not seeing?
TY

2

Don't use pins 0 and 1, they are reserved for serial transmission (RX/TX).

3

Post all your code, use the </> code tags button on the menu.

And don't use 0 and 1 as mentioned, those are used for USB to the PC.

4

Thank you both!
I don't mind posting my code but there is little more of it and also you solved my problem.
I thought I had a defective unit, but then the replacement was the same.
Ok, I will not use 0 and 1.
Have a great evening, my friends.

  • Michael