It would be great to have such nuances more explicitly noted in the documentation.
This is the first SoC where I see such strange GPIO configuration procedures, tricks and unclear documentation about that, and all this to use the basic functionality.
Jetson Nano Developer Kit 40-Pin Expansion Header Configuration appnote:
“The Jetson Nano Developer Kit carrier board includes a 40-pin expansion header. By default, all interface signal pins are configured as GPIO inputs, except pins 3 and 5 and pins 27 and 28, which are I2C SDA and SCL, and pins 8 and 10, which are UART TX and RX.”
Image is trivial and i dont see much choice, “Jetson Nano Developer Kit SD Card Image”, latest one at Jetson Download Center | NVIDIA Developer with keyword Jetson Nano .
I go inside of “Jetson_Nano_Developer_Kit_User_Guide.pdf”, and it is stated as well there:
"[J41] 40-pin expansion header includes:
•Power pins. Two 3.3V power pins and two 5V power pins. These are not switchable; power is always available when the developer kit is connected to power.Two 5V pins can be used to power the developer kit at 2.5A each.
•Interface signal pins.
All signals use 3.3V levels. By default, all interface signal pins are configured as GPIOs, except pins 3 and 5 and pins 27 and 28, which are I2C SDA and SCL, and pins 8 and 10, which are UART TX and RX. "
Thats clear, GPIO should work, isn’t it?