Conflict pin2 & pin7?

hi there

i tried to figure out why my notification led is not working after adding more sensors… so finally i found out what’s wrong, but i do not know why. here is a simple arduino sketch to illustrate the problem:

// the setup function runs once when you press reset or power the board
void setup() {
// initialize digital pin 13 as an output.
pinMode(7, OUTPUT);
pinMode(2, OUTPUT);


// the loop function runs over and over again forever
void loop() {
digitalWrite(2, HIGH); // turn the LED on (HIGH is the voltage level)
delay(1000); // wait for a second
digitalWrite(2, LOW); // turn the LED off by making the voltage LOW
delay(1000); // wait for a second

As soon as pin7 is set to output pin 2 is not able to go high i guess, means no blinking example. turn pin7 to input or comment out, things are working again.

why is this? any other pins not working in combination, rather painful to debug because on it’s own both pins are working but not in combination as it looks.


I will try the sketch right now.

I just test the sketch but not connected the LED. The pin 2 works as expect.

How did you connect the LED? Did you put a resistor at the board?

No, just a simple green led. Greens use more power apparently, so no resistor.

I have this issue with four boards running the example. So it’s definitely something with the board and implementation. what could this be?

I used the most simple blinking light example to avoid any other conflicts…

might it be that because of this the power output is not high enough to light the green led? i’ll try tonight with other leds and give feedback.


switched pins and it’s working. don’t know…

so far i could not figure out why this happens, but it does.