SABRE Board Power Button & Diode

[stephenbarton]

The SABRE Board schematic Rev. C5 Sheet 19 shows a diode D4 is connected from the Power Button SW1 to the PWR_BTN_SNS net that goes to EIM_D29 on the iMX6.  Can anyone say:

* What is the purpose of this diode connection?

* Is EIM_D29 configured as a GPIO input with a pull-up resistor?

The QWKS board schematic  Rev. C shows a similar diode D2 to EIM_A25.

- Thanks

[gusarambula]

Hello Stephen Barton,

On the first revisions of the SABRE schematic there was a Power On circuit that was ultimately left as optional. The SABRE now has an Auto ON feature and the diode added allows to sense when the power on button has been pressed. EIM_D29 pin is handled by the gpio-keys driver in order to generate an interruption when the power on button has been pressed.

I hope this information helps!

Regards,