gpio

      efusa9 revision 1.21

      We are having trouble with the GPIO on the efus board. We have tried to read pins 14 and 32 which correspond to /sys/class/gpio/gpio105 and /sys/class/gpio/gpio42.
      However we can not detect any change in the pins when set /sys/class/gpio/gpio#/value 0 or 1.

      Any help appreciated
      Oreste
      Did you really measure the pin? Because reading the value entry is *not* sufficient. The value that is output is not automatically available as an input, so reading the value file does not give back the current state of an output pin.

      Your F&S Support Team
      F&S Elektronik Systeme GmbH
      As this is an international forum, please try to post in English.
      Da dies ein internationales Forum ist, bitten wir darum, Beiträge möglichst in Englisch zu verfassen.
      Hi support,

      The pins were measured with a multimeter and when setting the value to "1" (using value file) the measured voltage remained at 0 for the RXDD pin.
      For the PVMA pin, the voltage remained on high even when the value is set to "0".

      So it looks like something else is a problem.

      Many thanks
      Oreste
      How did you change the device tree? For example pin 14 is occupied by UART port D if you use the standard device tree. So trying to write GPIO number 105 to /sys/class/gpio/export should fail if the device tree is not modified. Have you removed the pin settings for UART port D in iomuxc entries in efusa9qdl.dtsi?
      F&S Elektronik Systeme GmbH
      As this is an international forum, please try to post in English.
      Da dies ein internationales Forum ist, bitten wir darum, Beiträge möglichst in Englisch zu verfassen.