I stumbled on this tutorial: http://www.cl.cam.ac.uk/projects/raspberrypi/tutorials/os/ok01.html Unfortunately this is only made for the B rev2 board, whereas I got a B+ board and the board setup is slightly different. On the schematics of the rev2 version one can see that the ok LED is connected to the pin 16, which allows to activate the LED by writing into the respective registry.

But I couldn't find any schematics for the B+ version and thus could not identify to which pin any of the LED is connected. I am an absolute beginner regarding to this low-level approaches but would like to get through this tutorial with my board but got stuck at this point. I am not sure if I could damage the board by just trying to activate all the pins on the board and check what happens.

Do you guys know how and whether the on-board leds are connected to the pins? Or any other way to continue with my tutorial?

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    See /boot/overlays/README especially The base DTB By unpacking this you can deduce some of the pin settings. Most haven't changed from the B to B+ (P5 header excepted). Interesting is the act_led_trigger PS act_led on B+ is pin 47 – Milliways Dec 11 '15 at 2:46
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    Thank you!! It seems like this is the one. As soon as I have time to write the code and test it, I will post again – nemo Dec 11 '15 at 6:30
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    Hello nemo. Did you test it or learn something more? You're always welcome to write your own answer (or vote and/or accept for the existing ones). – Ghanima Dec 30 '15 at 23:05
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    I actually forgot to accept the other answer.. My bad! After some further googling if found that pther ppl already did the same tutorial for the b+ and the pi 2 – nemo Dec 30 '15 at 23:08

On the Pis with the 40 pin expansion header (except Pi3)

  • the power LED (red) is connected to GPIO 35 (not present on the Pi Zero)
  • the activity LED (green) is connected to GPIO 47

Pi3 uses a GPIO expander to drive the LEDs which can only be accessed from the VPU.


While there is a full schematics of the B, rev2 on Raspberrypi.org only some "Reduced Schematics" for the B+ are available. This is stripped down to the absolute minimum, but it is at least possible to figure out the pin numbering on the GPIO expansion header.

Another nice spot to visit is elinux which is updated with information of the different pin numbering of the numerous headers of the different models of the Pi.

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