Why the number pin12 of J41 on Nano devkit is 79?

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

The number of gpio is calculated with blow formula

value = offset+ (port number* 8 + pin value)
Where offset is 320 if the group is main, and offset is 256 if the group is aon.

The pin12 of J41 on Nano devkit is I2S0_SCLK(GPIO3_PJ.07). So its GPIO number shoule be (320 + 9*8 + 7) = 320 + 79 = 399.
Why it is number 19?

526×741 42.6 KB

2

79 is correct for sysfs port.

The formula is (port * 8) + offset

The pin is j7

TEGRA_GPIO_PORT_J = 9 so ( 9 * 8 ) + 7 = 79

From gpioinfo…
line 79: “I2S0_SCLK” unused input active-high

3

Hi gtj,

Thank you so much.
The pin16 above is GPIO3_PDD.00, so its mapping number is ( 29 * 8 ) + 0 = 232.
Cheer!

Best Regards.