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Connectcore MCA GPIO wakeup

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Im trying to use an interrupt on MCA-gpio 1 (configured as active high) to wake up my Connectcore 6UL SBC pro from standby. The interrupt pulls the line low.

I run:

gpiomon --num-events=1 --falling-edge mca-gpio 1 &

The problem is, when standby is run, the MCA gpio pins voltage drops to ~0.8V, triggering its own interrupt and waking it up near instantly. If I run standby without setting the interrupt, the voltage drops too.

Am I missing something to configure the MCA to maintain its voltage regulation etc?
asked Sep 10, 2021 in Linux by cstanton New to the Community (1 point)

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1 Answer

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Did you modify your device tree to contain something like this to configure MCA_IO0 as wake-up source:

&mca_gpio {
pwroff-wakeup-capable-ios = <1>;

then you need to do something like this:
This change in the device tree just enables the wake-up capability of the MCA GPIO. You still need to configure the GPIO as an interrupt on a running system. For example, to configure MCA_IO1 as falling-edge one-shot interrupt, use gpiomon with an ampersand at the end to send the task to the background. Then, power off:

~# gpiomon --num-events 1 --falling-edge mca-gpio 1 &
~# poweroff -f
The '-f' argument is necessary to prevent the poweroff sequence from closing gpiomon.

answered Sep 13, 2021 by LeonidM Veteran of the Digi Community (4,490 points)