Hi All, I'm running a quad with udoobuntu. I'm trying to wire a test switch (it's a simple two pin switch) to two GPIO pins. Both have to be GPIO pins (I'm later going to try a matrix). Basically: Set gpio 40 to output 0 Set gpio 3 to input with pullup Connect one switch pin to gpio 40 and another to gpio 3. I'd then cat /sys/class/gpio/gpio3/value and expect 1 when switch is not pressed, expect 0 when it is pressed. How can I activate the pullup resistor in gpio 3 via linux? Thank you
Hi cirrus, to set a pullup to a pin of the i.Mx6 Processor of UDOO you need to modifiy and recompile the kernel. You need to modify the file: <KERNEL_ROOT>/arch/arm/mach_mx6/board_mx6qd_seco_UDOO.h (for QUAD) or <KERNEL_ROOT>/arch/arm/mach_mx6/board_mx6sdl_seco_UDOO.h (for DUAL) adding a custom macro for the pin you want. You can find some Pinmuxing information in the "i.MX6 Pinmuxing" section of the Starting Manual downloadable here : http://www.udoo.org/downloads/#tab5 Otherwise you can use the Pin from Arduino side which already have input pullups
