5 Replies Latest reply on Mar 26, 2015 10:21 AM by ForumMigrationAdmin

    Enable serial on digital 0&1 on Galileo Gen 2


      We are trying to enable serial (ttys0) on digital 0 & 1 on Galileo gen 2 under WR Linux. I can find zero documentation from Intel on how the GPIOs are mapped in Linux (i.e. schematic vs Linux GPIOs). Based on schematic analysis and using the gpio information from the link below, I believe the proper settings to enable serial is:


      P0_0, on GPIO Expander 1 must be low (pulled up by default—R63) gpio32
      P0_1, on GPIO Expander 1 must be tri-stated (or remove R11) gpio33
      GPIO3_R from Quark must be tri-stated, gpio11
      P1_4, on GPIO Expander 0, must be set low,  gpio28
      P1_5, on GPIO Expander 0, must be set tri-state,  gpio29
      P1_5, on GPIO Expander 1, must be set high,  gpio45

      The problem we have is that under both Yocto and WR Linux, we get an error when trying to set GPIO11. Can you tell me the proper way to enable serial on dig 0&1? Here is the error we get:

      root@WR-IntelligentDevice:~# echo -n "11" > /sys/class/gpio/export

      root@WR-IntelligentDevice:~# echo -n "out" > /sys/class/gpio/gpio11/direction

      root@WR-IntelligentDevice:~# echo -n "hiz" > /sys/class/gpio/gpio11/drive

      -sh: echo: write error: Invalid argument