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nRF52833, about GPIO default states in System Off mode

natahan

Hi There,

Are the GPIO levels high impedance when the system is in off mode? Can you give information about their status? For example, one pin of the device is configured as pull-down. If the system is put into System Off mode from deep sleep modes, will the configured pin go into high impedance state? or will there be a change in the set pin configuration?

Thanks.

  • +1

    Hello,

    GPIO configurations made by the application are preserved when you enter System OFF mode, so if you want all pins to be in high impedance, you must ensure the pins you have used are configured back to their reset state before going to sleep.

    For example, one pin of the device is configured as pull-down. If the system is put into System Off mode from deep sleep modes, will the configured pin go into high impedance state?

    Then the pull-down will remain enabled.

    Best regards,

    Vidar

      

  • 0 in reply to Vidar Berg

    Thank you for the answer.

    Are the states kept as they were configured before a reset command (by pin or soft reset) during system reset or should we expect GPIOs to be in high impedance mode during reset? Will they be in the correct state after reset, or will they default to something default?

  • +1 in reply to natahan

    The pin state is only guaranteed to be high impedance after a system reset. The state during the reset is not defined, it may be the same as it was prior to the reset, or it may have the default high impedance state.

    Pin configuration when coming out of a reset:

     

  • 0

    Hello Vidar,

    what about in the case where the MCU is completely disconnected from POWER? my MCU is powered through a load switch and control when to enable it is based on external peripherals logic. The MCU is connected to external peripherals that are ALWAYS powered ON and I am seeing what I think is leakage back into the MCU as I am measuring approx. 0.3V on the MCU coupling caps when its powered OFF. the MCU is connected to external IMU, Memory, low power Accelerometers, and Hall sensors. All these external peripherals are connected via SPIM buses. Again, some of these are ALWAYS powered ON and some are only ON while the MCU is ON. the peripherals that are NOT always ON are also controlled via a load switch. I need to make sure the enable pin on the load switches of those peripherals that are disabled when the MCU is powered down are NOT floating. I do not want to use an external pull-down resistor as that would dramatically increase my power consumption when operating that sensor. your help will be greatly appreciated. 

    Regards,

    Wael

  • 0 in reply to Wael

    Hello Wael,

    You should not apply voltage on the IOs when the chip is not powered. This will exceed the Absolute maximum ratings of the chip, and the chip will become powered through the ESD protection diodes. 

     NRF52840 GPIO default state 

     Best regards,

    Vidar

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