Understanding the GPIO pins

Question

I've not yet got into the GPIO pins. Can someone help me understand how they work? Are some of them special in some way? Do certain pins produce certain polarities or is that software defined? What Voltage do they run on? Sorry for my ignorance and thank you for your time.

Edit: Ok, looking at the RPF docs was quite enlightening. However after the answer and some info in the docs, I have additional questions.

• What is the amp output on the GPIO pins?
• Does 3V3 on the RPF docs mean 3.3V or something else?

Answer 1

I've not yet got into the GPIO pins.

GPIO General Purpose Input Output (pin) - allows access to processor / hardware AKA interface to outside world.

Can someone help me understand how they work?

See above

Are some of them special in some way?

Yes.

In Broadcom ( RPi processor maker ) terminology - each "pin" can have u to 6 "alternate functions" - so the "general" is little misleading. (Confusing abbreviations of pins functions deliberately not included )

Do certain pins produce certain polarities or is that software defined?

No and no.

Better term is "level" and it is generally 0 V to 3.3V or 5V depending on processor.

What Voltage do they run on?

See above, however it is more important to know how much current GPIO pin can sink/load or supply/source.

Sorry for my ignorance and thank you for your time.

Welcome to the geek club.