Jetson Nano GPIO through direct memory access issues


Is there a delay in GPIO output or any additional steps to configure a pin for GPIO?

Currently, i’m trying to write a kernel module, and for debugging i’m trying to set a pin to high to just light up an led.

The pin i am configuring is pin 12 on the jetson nano header pins. From the pinmux, it is shown as PJ.07. So port J bit 07.

GPIO_CONF for port J is at 0x6000d204,
GPIO_OE for port J is at 0x6000d214,
GPIO_OUT for port J is at 0x6000d224.

To setup pin 7 on port J, i write 0x0080 to CNF to enable pin 7.
To enable output on Port J pin 7, I write 0x80 to OE.
I read from these addresses and I see that the changes have been made.

Now to set output to high and low, I write 0x80 to GPIO_OUT for high and 0x00 to GPIO_OUT for low.
I can read from the register and see the data being changed. However, no voltage stage changes on the pin. Is there a delay? Or any extra setup to configure GPIO?


hello jtran1028,

please also refer to Topic 144550, for several ways to access GPIOs. such as, kernel APIs, python scripts, C++ samples.