Read data from module INA3321 - Xavier NX

Autonomous Machines Jetson & Embedded Systems Jetson Xavier NX
1

I would need to monitor

•VDD_IN
•VDD_CPU_GPU_CV
•VDD_SOC

of the Xavier NX with an external device, over i2c (same idea as here: Read data from module INA3321). I would like to ask if the output of the INA32321 sensor is available on the Expansion Header of the carrier board.

3

hello Alessandro.B,

please enable tegrastats utility to shows the statistics reports in real-time. thanks

4

HI JerryChang,
thank you for your answer. However, what I would need to do would be to read the INA3321 over I2C and not from the tegrastats utility. I would need to read the INA3321 independently. If I don’t remember wrong, the Jetson AGX Xavier has the INA3321 connected to I2C 2 and these pins are available on the GPIO Expansion header. I was wondering if there is something similar for the Xavier NX. Thank you.

1 Like
5

hello Alessandro.B,

please access L4T sources, and check the Xavier NX power monitor device tree for reference.
for example,
$L4T_Sources/r32.4.2/Linux_for_Tegra/source/public/kernel_src/hardware/nvidia/platform/t19x/jakku/kernel-dts/common/tegra194-powermon-p3668.dtsi

6

Hi JerryChang,
I have opened the file you linked. But I’m not sure what to do. What I would need would be to bring the SDA, SCL, WARNING and CRITICAL pins of the INA3221 sensor to the GPIO Expander on the carrier board or the 260 pin connector of the SOM module. I’m not sure if this is possible (I don’t know if these pins can be accessed through changes on the Jetson_Xavier_NX_Pinmux_Configuration_Template_v1.06.xlsm file). I see that the GPIO expander on the carrier board has two I2C buses available: I2C0 and I2C1. Is it possible to change the dts file to do this? If yes, could you help me with that?

Another question: what is the number of the I2C bus where the INA3321 is connected to?

Thank you.

7

Hi,
I tried to figure this out, but without success. What should I do once I open the file $L4T_Sources/r32.4.2/Linux_for_Tegra/source/public/kernel_src/hardware/nvidia/platform/t19x/jakku/kernel-dts/common/tegra194-powermon-p3668.dtsi?

Thank you.

8

hello Alessandro.B,

you may refer to device tree for the i2c address of the ina3221;
for example, you could check below two dtsi files for comparison of Xavier and NX.
Xavier:
$L4T_Sources/r32.4.2/Linux_for_Tegra/source/public/kernel_src/hardware/nvidia/platform/t19x/galen/kernel-dts/common/tegra194-powermon-p2888.dtsi
NX:
$L4T_Sources/r32.4.2/Linux_for_Tegra/source/public/kernel_src/hardware/nvidia/platform/t19x/jakku/kernel-dts/common/tegra194-powermon-p3668.dtsi

you could access sysnode for checking, i.e. $ cd /sys/bus/i2c/drivers/ina3221x/7-0040/iio_device
thanks