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Use of GPIO pins
Posted: Sun Jun 14, 2020 5:53 pm
by edsulst
Hi There,
For my project I'm using 17 GPIO pins, but I need one extra.
The GPIO pins I'm using are alle the green one's as mentioned here:
https://www.raspberrypi-spy.co.uk/2012/ ... tyPhoto/1/
Is it possible to use another GPIO pin, for example 2, 3, 9 or 10, as an input as well ?
Gr. Edwin
Re: Use of GPIO pins
Posted: Sun Jun 14, 2020 6:03 pm
by B.Goode
edsulst wrote: ↑Sun Jun 14, 2020 5:53 pm
Hi There,
For my project I'm using 17 GPIO pins, but I need one extra.
The GPIO pins I'm using are alle the green one's as mentioned here:
https://www.raspberrypi-spy.co.uk/2012/ ... tyPhoto/1/
Is it possible to use another GPIO pin, for example 2, 3, 9 or 10, as an input as well ?
Gr. Edwin
The 40-way header on all recent RPi boards has 26 programmable gpio pins. See
https://pinout.xyz/
Do you have very early hardware with only a 26-pin header?
Re: Use of GPIO pins
Posted: Sun Jun 14, 2020 7:13 pm
by hippy
The blue, purple and pink marked GPIO pins are used for specific special purposes but can also be used as general purpose input or output if not otherwise used.
Re: Use of GPIO pins
Posted: Sun Jun 14, 2020 7:19 pm
by DougieLawson
B.Goode wrote: ↑Sun Jun 14, 2020 6:03 pm
The 40-way header on all recent [sic] RPi boards has 26 programmable gpio pins. See
https://pinout.xyz/
Do you have very early hardware with only a 26-pin header?
"Recent" being since the release of the original B+ in July 2014.
Re: Use of GPIO pins
Posted: Sun Jun 14, 2020 7:45 pm
by edsulst
Sorry, but I forgot to tell you that I have a Raspberry Pi 3 model B V1.2 with a 40 pin header.
Now I only used the green colored pins and I wasn't sure if other colors could be used.
But if I read the posts correctly it's possible to use the blue, purple and pink also. GREAT !!
I did read somewhere that the yellow color pins can't be used
Since you never mentioned the yellow color I think that's right.
Re: Use of GPIO pins
Posted: Sun Jun 14, 2020 8:31 pm
by DougieLawson
edsulst wrote: ↑Sun Jun 14, 2020 7:45 pm
Now I only used the green colored pins and I wasn't sure if other colors could be used.
What? The pins on a regular RPi are not coloured in any way.
https://pinout.xyz shows you which pins are which.
Re: Use of GPIO pins
Posted: Sun Jun 14, 2020 8:38 pm
by rpdom
It does indeed, and oh, look... the pins are coloured in that image!
Re: Use of GPIO pins
Posted: Sun Jun 14, 2020 9:38 pm
by DougieLawson
Those colours aren't on a physical RPi3B.
There are coloured headers you can solder in to a Zero
https://shop.pimoroni.com/products/colo ... io-headers but they don't match
https://pinout.xyz
The 3.3V, 5V, and GND pins are not GPIOs.There are 28 usable GPIOs.
Re: Use of GPIO pins
Posted: Mon Jun 15, 2020 9:36 am
by Burngate
DougieLawson wrote: ↑Sun Jun 14, 2020 9:38 pm
Those colours aren't on a physical RPi3B.
Do we really need to argue about where the colour is? It seems obvious to me that edsulst is referring to the colouring used by raspberry-spy.
edsulst wrote: ↑Sun Jun 14, 2020 7:45 pm
I did read somewhere that the yellow color pins can't be used
Since you never mentioned the yellow color I think that's right.
If you're referring to pins 27 & 28, it's best not to use those GPIOs since at boot-up, the Pi checks them for HATs, and can get its knickers twisted if something's connected to them.
Re: Use of GPIO pins
Posted: Mon Jun 15, 2020 9:41 am
by DougieLawson
Burngate wrote: ↑Mon Jun 15, 2020 9:36 am
DougieLawson wrote: ↑Sun Jun 14, 2020 9:38 pm
Those colours aren't on a physical RPi3B.
Do we really need to argue about where the colour is? It seems obvious to me that edsulst is referring to the colouring used by raspberry-spy.
I didn't click that Raspberrypi-Spy URL as it includes a date of "2012/06" so I'd assumed it was for the 26 pin Raspberries.
My URL of choice for the pins is
https://pinout.xyz as it has added value that each pin can be clicked for a description and there's stuff for I2C, SPI, etc. and a whole raft of HATs and pHATs on there.
Re: Use of GPIO pins
Posted: Mon Jun 15, 2020 9:57 am
by edsulst
Thank you all for answering to my question.
It's clear to me now that I can use more pins than I thought.
// Edwin