GPIO Pin Numbering Confusion

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1

I'm confused by the GPIO pin numbering shown on the Bone101 support page:

http://beagleboard.org/Support/bone101

P9 pins 28-31 are listed as GPIO_120 through GPIO_123, which seems to be
off by 10. The schematic shows these as GPIO bank 3, pins 14-17, which
by my understanding should be:

  ( 32 * 3 ) + 14 = 96 + 14 = 110
  ...to...
  ( 32 * 3 ) + 17 = 96 + 17 = 113

Other GPIO bank 3 pins (like P9 pin 27) are labeled as I would expect
(GPIO3 pin 19 = GPIO_115).

Is the documentation on the Bone101 page wrong, or am I confused about
the kernel GPIO numbering scheme?

Note: This all started with a bug report about pin numbers for the
universal overlay:

https://github.com/cdsteinkuehler/beaglebone-universal-io/issues/18

2

Double check against these:

https://github.com/derekmolloy/boneDeviceTree/tree/master/docs

At one time i had the equation down, but derek's eye chart works better. :wink:

Regards,

3

That shows the GPIO pin numbers to be 110-113, as I expected. It looks
like the 120-123 numbers on the Bone101 web page graphics are incorrect.

...who gets the bug report?

4

I’m confused by the GPIO pin numbering shown on the Bone101 support page:

http://beagleboard.org/Support/bone101

P9 pins 28-31 are listed as GPIO_120 through GPIO_123, which seems to be
off by 10. The schematic shows these as GPIO bank 3, pins 14-17, which
by my understanding should be:

( 32 * 3 ) + 14 = 96 + 14 = 110
…to…
( 32 * 3 ) + 17 = 96 + 17 = 113

Double check against these:

https://github.com/derekmolloy/boneDeviceTree/tree/master/docs

At one time i had the equation down, but derek’s eye chart works better. :wink:

That shows the GPIO pin numbers to be 110-113, as I expected. It looks
like the 120-123 numbers on the Bone101 web page graphics are incorrect.

…who gets the bug report?

That would be me. Better now?

5

Yes Jason, that looks much better!

Thanks for the quick fix!

6

Why do i feel like im becoming less intelligent by reading these posts ?