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  • Case ID: 298582
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Disable UART1 of nrf52840 DK and re-configure pins as GPIOs at runtime

siwa

Hi,

we are currently using NCS 2.0.2 on nRF52840.

Is it possible to disable uart1 via pinctrl or another library during runtime and re-configure the rx/tx as gpios?

We need to set the two pins in low-state to allow another module enter its sleep mode while the nrf stays awake.

Regards,

Simon

  • 0

    Hi Simon, 
    Your question is similar to this question here.

    Our answer for now is that it's not possible. You can have a look here: https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/zephyr/hardware/pinctrl/index.html#dynamic-pin-control

    Dynamic pin control should only be used on devices that have not been initialized. Changing pin configurations while a device is operating may lead to unexpected behavior. Since Zephyr does not support device de-initialization yet, this functionality should only be used during early boot stages.

  • 0 in reply to Hung Bui

    Hi Hung,

    Thanks for your quick reply.

    Then I have a further question. Is it possible to set them (tx/rx) low during sleep mode?

  • +1

    Hi Simon, 
    Which sleep mode are you looking at ? 
    If you are thinking of system OFF I do think that it's possible. You can suspend UART and then use the nrf_gpio_* library to access the pins and change the state. (see system_off sample) . The main point here is that if you are entering system OFF , it's not very important how they would work after the system OFF entered. The chip will reset and start from beginning when waking up anyway. 

  • 0 in reply to Hung Bui

    Thanks, that works!

    Even in the busy wait loop, the UART pins can be set low or high after the suspend command is called.

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