5 Replies Latest reply on Mar 8, 2015 6:57 AM by Bylos

    How to use UART1 (/ttyMFD1) with Edison without Arduino board ?


      Dear all,


      I am currently trying to use the serial /ttyMFD1 from Eclipse IDE on a breakout board which is not the Arduino board (SparkFun Block for Intel® Edison - GPIO - DEV-13038 - SparkFun Electronics)

      Unfortunately the RX pin (GPIO 130) and TX pin (GPIO 131) remain stuck at level low (0V).


      I tried some tests in the console with manual configuration of the pins with the following code, but the problem is the same :

      // setup RX pin
      echo -n "130" > /sys/class/gpio/export
      echo in > /sys/class/gpio/gpio130/direction
      echo 1 > /sys/class/gpio/gpio130/value
      echo mode1 > /sys/kernel/debug/gpio_debug/gpio130/current_pinmux
      // setup TX pin
      echo -n "131" > /sys/class/gpio/export
      echo out > /sys/class/gpio/gpio131/direction
      echo 1 > /sys/class/gpio/gpio131/value
      echo mode1 > /sys/kernel/debug/gpio_debug/gpio131/current_pinmux


      With this code, TX and RX pin values are still 0V. This is the same if I use "mode0" for pinmux value to set these pins as standard GPIO

      But if I do this with a "classic" GPIO like GPIO44, I can easily switch direction and value, everything works as expected.


      I think there might be something specific that I am missing for the TX and RX pins but I definitely can't find what it is...


      Any help would be greatly appreciated !