Hi Cheryl,

I'm new to the list, but I have the tobi board here and have been playing with gpio the last couple days.

I would recommend searching for "gpio" at wiki.flightgear.org and follow the example there -- it worked for me:


The example uses gpio146 which ends up on pin #27 of the 40 pin header.  Note the pin ordering is staggered as per the 2nd to last page of the schematic:


I see GPIO10 is brought out to pin 18 and it appears to be configured in mode 4 (gpio) in the overo.h header in the u-boot loader by default.  So I would think GPIO10 would work too, unless it's being used already by some other driver or device???

If you want to set the value and measure the voltage, then the direction you want is "out".

Hope that helps,


On Mon, Jun 13, 2011 at 8:31 PM, Cheryl Skibski <cherylskibski@gmail.com> wrote:
I am a graduate student working on a project with the Gumstix Overo Fire and Tobi Expansion Board. This is my first time working on a Linux embedded computing project ever so help would be much appreciated. 

My task is to create a python code for a GPIO (I was planning on GPIO10). This code will turn the pin high to have a voltage output and then turn the pin low. 

I was doing some testing in the command line with the following prompts: 

echo "10">/sys/class/gpio/export 
echo "out">/sys/class/gpio/gpio10/direction 
echo "1">/sys/class/gpio/gpio10/value 
Measured with an oscilloscope using PIN 15 as GND 
echo "in">/sys/class/gpio/gpio10/direction 
echo "o">/sys/class/gpio/gpio10/value 
Measured with an oscilloscope 

I saw no change when measuring both times. 

I have been reading multiple forums and all of them seem confusing and complicated. All I want to do is turn the pin high. 

For the python code I figured I would be doing something according to these steps to make the pin high: 
open /sys/class/gpio/gpio10/value 
write a 1 to the value 

Thanks in advance 

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Curtis Olson:
http://www.atiak.com - http://aem.umn.edu/~uav/
http://www.flightgear.org - http://gallinazo.flightgear.org