NRF91 power save mode with CONFIG_SERIAL=y

RE: NRF91 power save mode with CONFIG_SERIAL=y

Bjørn Kvaale — Fri, 09 Aug 2019 10:46:46 GMT

@jbrzozoski I am not sure whether there will be support for this in the future. Could you please ask your local Regional Sales Manager? If you do not know who this is, send me a PM on DevZone with your country location & I can put you in touch.

RE: NRF91 power save mode with CONFIG_SERIAL=y

almogalm — Thu, 08 Aug 2019 14:48:23 GMT

hi Bjørn Kvaale, in blog post you mentioned they use CONFIG_SERIAL=n to disable uart on precompilation.

RE: NRF91 power save mode with CONFIG_SERIAL=y

jbrzozoski — Thu, 08 Aug 2019 14:28:13 GMT

Looking around in the guts of Zephyr and NRFX, the UARTE drivers already have some level of support for disabling them in run-time. It looks like most of that functionality is tied into the API enabled via CONFIG_SYS_POWER_MANAGEMENT, but that is currently not supported on the nRF9160. Is that support on the roadmap anywhere?

RE: NRF91 power save mode with CONFIG_SERIAL=y

Bjørn Kvaale — Thu, 08 Aug 2019 13:36:40 GMT

That seems roughly correct, depending on what you are doing. Maybe this blog post could also help a bit.

RE: NRF91 power save mode with CONFIG_SERIAL=y

Yusuke — Wed, 07 Aug 2019 14:55:35 GMT

Hi, Bjorn. Thank you so much! This code works out.

void disable_uart(){
        NRF_UARTE0->TASKS_STOPTX = 1;
        NRF_UARTE0->TASKS_STOPRX = 1;

        NRF_UARTE3->TASKS_STOPTX = 1;
        NRF_UARTE3->TASKS_STOPRX = 1;
}

void enable_uart(){
        NRF_UARTE0->TASKS_STARTRX = 1;

        NRF_UARTE3->TASKS_STARTRX = 1;
}

A current around 25uA is consumed on DK v0.8.5 while the UART RX is off. Is this reasonable value? I read datasheet and it doesn't describe current consumption of UART. Let me know the value, if you have measured.

RE: NRF91 power save mode with CONFIG_SERIAL=y

Bjørn Kvaale — Wed, 07 Aug 2019 14:00:29 GMT

You cannot change flags in runtime, but you can turn off the uart RX if needed. See this code for more info.

RE: NRF91 power save mode with CONFIG_SERIAL=y

Yusuke — Mon, 05 Aug 2019 16:35:36 GMT

I don't know how to solve the issue, but this might help you.

https://github.com/zephyrproject-rtos/zephyr/pull/7034