nRF91 UART Sleep Current – AT Host deinit & pm_device_action_run() for Low Power

RE: nRF91 UART Sleep Current – AT Host deinit & pm_device_action_run() for Low Power

Akshay — Wed, 02 Jul 2025 12:26:52 GMT

Hi,

I managed to get it working by creating an instance of uart0(AT host uart) in my application and disabling it like this.

const struct device *at_uart = DEVICE_DT_GET(DT_NODELABEL(uart0));

void disable_at_interface(void){
    uart_irq_rx_disable(at_uart);
    pm_device_action_run(at_uart, PM_DEVICE_ACTION_SUSPEND);
}

Thanks for the help.

regards,

RE: nRF91 UART Sleep Current – AT Host deinit & pm_device_action_run() for Low Power

dejans — Wed, 02 Jul 2025 12:18:40 GMT

Hi,

CONFIG_SERIAL=y activates all uart instances that have status ok in the devicetree.
You can use ENABLE register to check if UARTE is enabled or disabled.
If you do not need peripheral and you want to put the system in the lowest power state, you can follow low power documentation and first stop and then disable the peripheral. You can also look at this Device PM and nrfx UARTE discussion.

Best regards,
Dejan

RE: nRF91 UART Sleep Current – AT Host deinit & pm_device_action_run() for Low Power

Akshay — Wed, 02 Jul 2025 07:58:52 GMT

hi,

I have disabled both uart0 and uart1 in code using rx_irq_disable function and suspended them using power management api. Still it is drawing 630uA. the AT host library must be enabling another instance of uart0. How do I disable the AT host library in runtime?!

regards,

RE: nRF91 UART Sleep Current – AT Host deinit & pm_device_action_run() for Low Power

dejans — Wed, 02 Jul 2025 07:45:00 GMT

Hi,

You can check if you have more than one UARTE instance enabled.

Best regards,
Dejan

RE: nRF91 UART Sleep Current – AT Host deinit & pm_device_action_run() for Low Power

Akshay — Tue, 01 Jul 2025 16:18:29 GMT

Hi Dejan,

Apparently that didn't work for me, it's still drawing 630uA. Only CONFIG_SERIAL=n is bringing down the current to 40uA(as I have SAADC and some other peripherals enabled).

Regards,

RE: nRF91 UART Sleep Current – AT Host deinit & pm_device_action_run() for Low Power

dejans — Tue, 01 Jul 2025 15:19:52 GMT

Hi,

[quote user=""]Does the nRF91 UARTE driver support PM device suspend/resume using pm_device_action_run() in NCS v2.7.0?[/quote]

Yes, use of pm_device_action_run() is supported by UARTE driver in NCS v2.7.0.

Best regards,
Dejan