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i am on Ubuntu 20.04 on RPI4. I am driving a 4 PWM motor driver using PWM on pins 22,23,26,27. When i turn off the raspberry, the driver being still powered, go off. I suppose some of this pins change state to HI. Is there a way to power off the RPI4 assuring the pins stay LOW ? Thanks

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  • always assume that the pins will float when the microcontroller is powered off ... design external circuitry with that in mind ... also, the motor driver should not drive any microcontroller pins high when the microcontroller is powered off
    – jsotola
    Commented Sep 26, 2022 at 15:24
  • thanks for the reply @jsotola . I don't think the motor driver affects the RP pins when it's off. but i will check that too Commented Sep 26, 2022 at 16:25

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If you want to ensure the GPIO are low at power-off connect each GPIO to ground via a 4k7 resistor.

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Your Question asks about "pin state after shutdown" - in general pins retain their state if powered.

You later state "i turn off the raspberry" - if unpowered the pins obviously have no voltage so state is meaningless.

It is unclear what you have done or WHY you would want to turn off power while apparently leaving the motor driver powered.

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