Meaning and pin of GPIO243

Hi to everyone,
today I tried to compile a binary, but it give me an error to access at GPIO243 port, exactly the error is:

cannot create /sys/class/gpio/gpio243/value: Directory nonexistent

I searched on the web and i only found that the 243 GPIO correspond to TEGRA_GPIO_PEE3 but i didn’t find the meaning of PEE and the pin corresponding. Anyone can help me?

Another question, there is a solution to monitor the port request by a running program? I’m trying to do a reverse engineering and the only solution that i found is to run the program with a debugger, but is not so clear end easy to understand!


The Technical Reference Manual gives information on GPIO controllers, one of those controls GPIO label PEE3. This happens to be enumerated 243 in header files. 243 being the number which can be exported or unexported to make it visible in “/sys”. Note that if you are working with software for some other variation of board that actual “/sys” location may change, but on R21.5 of a TK1 go to this directory as root (“sudo -s”) and look at files “export” and “unexport”:


I don’t know what other things may use 243, but you could cause “/sys/class/gpio/gpio243” to show up via:

echo 243 > /sys/class/gpio/export

…or make it go away via:

echo 243 > /sys/class/gpio/unexport

If you can manually get what you want to work, then the dtb file can be modified to make this available at boot without intervention.

Thanks for the prompt reply,
i downloaded the Technical Reference Manual and now I search for information about it, because I didn’t find the position in GPIO I/O header.

There is a schematic of the carrier board also available. Not all GPIO is exposed to headers. Some go to J3A1 or J3A2.