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So far, my ignorance was bliss.
I was able to control the GPIO pins and for many years, the world made sense to me
But then I saw this: enter image description here

And wires got crossed in my brain

Why does it say that GPIO7 is at pin 7 of the 40pin connector, while this documentation https://www.raspberrypi-spy.co.uk/2012/06/simple-guide-to-the-rpi-gpio-header-and-pins/ says that GPIO7 is at pin 26 ? (and that is how I have been using it for years)

Are those two different "standards"? and which one is to be used when?

PS: I'm running Raspbian GNU/Linux 11 (bullseye)on a rpi4

thank you for helping to get my sanity back
chrisV

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2 Answers 2

Reset to default
5

GPIO.7 is the wiringPi name for GPIO 4.

There are three naming schemes in common use.

  • Broadcom numbers. These are the GPIO numbers used by the manufacturer and are the ones used by the operating system.
  • Pin numbers. If a GPIO is routed out to the expansion header it may sometimes be referred to by pin number. E.g. GPIO 4 is connected to pin 7.
  • wiringPi numbers. These are the numbers used to identify the GPIO when using the wiringPi library.

I suggest you stick to using Broadcom numbers.

See https://pinout.xyz/

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  • Thank you @joan for your answer. It makes a little more sense now.
    – Chris V.
    Commented Aug 5, 2022 at 5:21
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    Adding: That wiring pi scheme seems also be used by the python library RPi.GPIO (import RPi.GPIO as GPIO) Too bad that both "standards" are referring to it as plain GPIO. We have miles and kilometers and Pounds and Kilograms, but at least those have a different name.
    – Chris V.
    Commented Aug 5, 2022 at 5:44
  • RPi.GPIO uses Broadcom numbering (BCM) or pin numbering (BOARD). It does not use wiringPi numbering.
    – joan
    Commented Aug 5, 2022 at 7:44
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When WiringPi was initially released in 2013 Gordon used 'wiring' pin numbers to make it similar to Arduino.

This probably seemed like a good idea at the time, but has since caused considerable confusion.

The Pi only understands BCM numbers; programs which use Board (or other) numbers have to translate to BCM numbers.

When WiringPi was deprecated I wrote a GPIOreadall replacement for the wiringpi gpio readall utility. This uses BCM (and Board) numbers and has a few enhancements.
GPIOreadall can be downloaded from https://github.com/Milliways2/GPIOreadall

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  • cool, thank you @Millways. I installed your gpioreadll.py and removed the other one.
    – Chris V.
    Commented Aug 5, 2022 at 5:33

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