Beagleboard-Xm GPIO Input

Hey so I have installed Archlinux on my beagleboard and I am trying to receive input via gpio pins from the expansion port.

So far I was able to use GPIO157 (pin 22) to output high(1.8V) and low(0V) to a breadboard. I now want to TAKE IN a signal. I finally found out how to do this in a way. I found that GPIO136(pin 9) and GPIO137(pin 7) is active HIGH, as in if nothing is attached or inputted I get a value = ‘1’. If I give it 0V from a DC power supply, it will go to ZERO(0V). In that way it does respond to input signal.

What I was wanting to figure out is if there is a pin (ie GPIO135(pin 11)) that will respond to a high input voltage and the gpio toggle to go HIGH. I tested GPIO135 and it is active LOW but when I give it 1.8V, its STILL low. Does anyone know how to fix this, possibly without having to change/recompile UBOOT?




make sure that gpio 135 is configured as input in the kernel. It can be
done through the gpio driver interface at /sys; Or build time in
arch/arm/mach-omap2/board-omap3beagle.c; or even pre-configured in uboot
bootloader. I just looked at uboot default configuration of gpio135 for
you and it is already configured as input. Make sure that the kernel does
not reconfigure it again at bootup (when kernel pin-mux mode feature is
enabled). otherwise, use another pin.