Hello,
this is more about a confirmation than anything else (or correction if wrong).

When we have a peripheral connector with unused pins, the good practice is to connect the unused pins to a GND, right? To avoid logical level flicking because of the surrounding noises...? How critical are the those flickers to pins that aren't even used?

Just curious.

Regards,

 

Connect unused inputs only, not unused outputs.

Whether you connect to Vcc or GND depends on the function of the input pin.

 

Solder a pull-up/down resistor.

 

Connect unused inputs only, not unused outputs.

Whether you connect to Vcc or GND depends on the function of the input pin.

My favorite question: Why? Why stabilizing the logical level of inputs only? What happens if we don't do that? I know this might be a very basic question, but I've just entered into the world of electronics.

 

The pin will act as an antenna and it can introduce EMI in your signals.

 

The answer is maybe or depends on the specific details/functions/requirements of that product..
I'll tell you that I don't ever have any unused pins on "peripheral connectors" (chips/ICs yes and I follow the recommended practice in the datasheet)..
The extra/unused pins in a connector simply cost money..
If its unused.. why even have it in the first place.

 

Are you referring to input pins on an IC or pins on a connector that are N/C (not connected)?

 

Nice answer from both of you. I see the chosen design is already a bad practice given the partial use of peripheral connectors. Also, now I understand the idea of parasitic EMI; every signal affects the other. Flickering signals that are too close will affect the precision or proper working of other neighbouring signals.

Case closed.

 

Are you referring to input pins on an IC or pins on a connector that are N/C (not connected)?

In fact, the peripheral connectors (if the name was correctly used) I am referring to are like this:

From one PCB board to another with a multi-wire bus male connector.

 

It depends on what is connected to the pin.

I would say leave the pin alone - don't connect anything unless you are told to connect to something.

 

Usually you attach to whatever results with the lowest power dissipation.