Xavier ，jeppack4.6, How should I use the GTE (Generic Timestamp Engine) output?

[nvidias]

Hi ，
I use Xavier，jetpack4.6，and test the GTE（Generic Timestamp Engine） functionality with the following documentation：

Generic Timestamp Engine

Everything seems to be fine.But I am not sure how to use the GTE output（the figure below）, please give me some suggestions, Any suggestions would be appreciated！

Thanks！
BR.

[JerryChang]

hello nvidias,

may I know what’s the actual use-case, what’s the purpose of your user space sample application,
thanks

[nvidias]

Hi JerryChang,

Thanks for your reply!

I use $ ./gte_mon -d gtechip0 -g 257 -r -f & use-case, We want to use GTE to sync other devices,and I wonder what "HW timestamp GPIO EVENT 7301997619552"
the “7301997619552”means? How to convert to UTC time?
Thanks！
BR.

[JerryChang]

hello nvidias,

here’s formula, clock_gettime(MONOTONIC_RAW) = cycle_ns(TSC) - offset_ns
GTE block (GPIO Timestamping Engine), which can be used to capture the TSC timestamp based on gpio interrupts or events.
and, the offset is under… # cat /sys/devices/system/clocksource/clocksource0/offset_ns

please following above to calculate the timestamp with TSC,
thanks

[nvidias]

Hi JerryChang，

Thank you for your reply！
Do you mean the “7301997619552” stands for TSC？
I hope you can explain how to use it in more detail，thank you!

Thanks,
BR.

[JerryChang]

that’s shown the hardware timestamp in nanosecond, you should adding the offsets for mapping to MONOTONIC_RAW.