UART for low power - is it possible to "wakeup" the nrf9160?

[Colby]

Howdy,

To achieve the lowest possible power consumption on the nrf9160, it is noted that it is necessary to disable the UARTs that are not used, when in sleep mode.
However, when the UART is in this disable mode, is it possible to configure the UART so that the reception of a character on the UART's RX line would "wakeup" the nrf9160 from it's low power sleep? If that is not possible, what is the recommendation? Configuring the pin as a GPIO to detect a transition on RX, waking up, and then re-configuring the pin as a UART?

Using Zephyr OS, is there a software hook that needs to be hooked so that custom low power actions needed to achieve the low power state are executed on the way into and out of low power?

V/R,

-Colby

[Sigurd]

Hi,

Colby said:

However, when the UART is in this disable mode, is it possible to configure the UART so that the reception of a character on the UART's RX line would "wakeup" the nrf9160 from it's low power sleep?

Yes, that it's possible. What sleep mode do you have in mind ? System ON sleep, or System OFF sleep ?

If it's System OFF mode, then you might find this small sample useful.

Colby said:

Using Zephyr OS, is there a software hook that needs to be hooked so that custom low power actions needed to achieve the low power state are executed on the way into and out of low power?

There seems to be some kind of suspend hooks in subsys/power/device.c, but as of today nRF9160 support has not been added yet.

[Colby]

Howdy Sigurd,

Sigurd said:

What sleep mode do you have in mind ?

We will more than likely be in System ON Sleep mode rather than System OFF.

Sigurd said:

There seems to be some kind of suspend hooks in subsys/power/device.c, but as of today nRF9160 support has not been added yet.

Is there any roadmap or estimates for the timeframe on that support?

Thank you for your time!

V/R,

Colby

[Colby]

Howdy Sigurd,

Has there been any updates on the information related to the question at the end of my response?

Sigurd said:

There seems to be some kind of suspend hooks in subsys/power/device.c, but as of today nRF9160 support has not been added yet.

My previous question -> Is there any roadmap or estimates for the timeframe on that support?

We are trying to stay ahead of our timeline for development and would like to have an idea of when we may expect the firmware support. Thank you for your time

V/R,

Colby

[Sigurd]

Colby said:

Is there any roadmap or estimates for the timeframe on that support?

It's been requested but no timeline yet. There are several ways it could be implemented, e.g. use dedicated GPIO pin, or re-configure RX pin from UART to normal GPIO(detect transmission) or use the HW flow-control mechanism. Some approaches are described in this old repo for the nRF51-series.

[Colby]

Not the answer we hoped for, but it does give us something to act one. Thank you for your help and assistance Sigurd!

V/R,

Colby