PPS On Jetson Xavier AGX with Rogue Carrier Board

Robotics & Edge Computing Jetson & Embedded Systems Jetson AGX Xavier
1

Hello, I am trying to set up a GPIO pin from the Jetson AGX to act as a PPS using the internal clock. I can only find instructions for setting up the pin 32 using the developer kit, but I am using the rogue carrier board so I do not have access to that pin. I tried setting up the kernel just using a different GPIO pin, but did not have any luck. I am not sure if I am doing something wrong or if the internals of the Jetson do not allow all pins to access the internal clock. I was hoping you could provide some further insight into this to know if it is possible. Thank you!

3

Hi,

Any GPIO pin should be able to be configured and used for PPS.
I don’t think there is any restriction on what pin you can use.

4

Ok, in that case I am trying to customize the SPE firmware to produce an output on a pin (specifically gpio417) using the gpio-app. The example shows the output on pin 16 (gpio256) but due to constraints of my carrier board I do not have access to that pin so am trying to use a different one. However, rebuilding and flashing the SPE firmware does not produce the desired effect and there isn’t much info on how to debug why this is the case since this is running on the firmware level and I can’t see any print statements. Could there be any other pin settings that need to be changed that are already assumed for pins BB0 and BB1? Alternatively, do you have any suggestions on how I can debug what is happening?

I am following this tutorial: Jetson Sensor Processing Engine (SPE) Developer Guide: GPIO Application (app/gpio-app.c)

5

I think you can first try with other PPS applications that does not involve SPE/AON GPIO pins.

6

I have tried making a PPS with other methods, but I found that the time is not precise enough and the pulse is affected by other processes within the system so I am looking for a more precise way of doing it. The SPE with a GPIO as an interrupt sounds like exactly what I need. Is there any way to do this? Or do you have suggestions for other PPS methods that would provide more accuracy?

7

Can you please check this guide?
https://docs.nvidia.com/jetson/archives/r36.2/spe/md__home_jenkins_agent_workspace_Utilities_rt_aux_cpu_demo_fsp_docs_work_rt_aux_cpu_demo_fsp_doc_gpio.html

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