Info Raspberry Pi GPIO Pinout: What Each Pin Does

[apiltch]

The Raspberry Pi has 40 GPIO pins that connect to sensors, lights, motors and other devices. Here's a map and detailed explanation of what each does.

Raspberry Pi GPIO Pinout: What Each Pin Does : Read more

 

[DotNetMaster777]

Very nice and useful article !!

 

[MatsK]

It has a serious error.

The operating voltage of the GPIO pins is 3.3v with a maximum current draw of 16mA. This means that we can safely power one or two LEDs (Light Emitting Diodes) from a single GPIO pin, via a resistor.

The typical values for a 3 or 5mm LED is 1,8-3volt and 20mA depending on color and just one LED is over the maximum for the GPIO. So the statement in the article could potentially burn the GPIO pin!

Please correct the article.

 

[seamusdemora]

SCL4 (I2C clock) appears on two different pins:
pin 26 (GPIO 7)
pin 21 (GPIO 9)

There are other errors - are you confused - or is it me??

 

[chmedly]

It has a serious error.

The operating voltage of the GPIO pins is 3.3v with a maximum current draw of 16mA. This means that we can safely power one or two LEDs (Light Emitting Diodes) from a single GPIO pin, via a resistor.

The typical values for a 3 or 5mm LED is 1,8-3volt and 20mA depending on color and just one LED is over the maximum for the GPIO. So the statement in the article could potentially burn the GPIO pin!

Please correct the article.

Any circuit that drives an LED is going to have some form of current limiting. In most micro controller (and raspberry pi) schematics you'll see a resistor in series with the LED. This is the resistor mentioned in the article. This resistor controls the amount of current that will flow in the circuit.
As you've stated, many LED spec sheets mention 20mA as the typical current. But most LEDs will still light up with far less current, just not as brightly. If you are using the LED as an indicator with an RPI I would expect that you could drive them with as little as 3-5mA and get suitable brightness. Considering the 3.3v GPIO output of a pi and a typical red LED, I would suggest a 330 Ohm resistor which will limit the current to well below the maximum capacity of the RPI.