Jetson TX1/TX2 PPS (pulse per second) on pin B18

Hello!

We have the following task. We creating a custom carrier board.
On it we have a microcontroller (stm32) and a GPS/GLONASS chip with very high accuracy.

Information about the time and coordinates we transmit through the UART from the microcontroller. But we need to synchronize the time with the microcontroller with an accuracy of at least 100 microseconds.

The engineers who developed the carrier for this purpose used a pin B18 (GNSS_PPS).

On this occasion, we have disagreements. Can we process the PPS signal (pulse per second) through this pin?
How can we to do this (on software layer)?

P.S. Jetson TX1/TX2 Developer Kit Carrier Board on page 6 … information about GNSS_PPS on B18 (on developer kit)

Related post https://devtalk.nvidia.com/default/topic/970586/adding-pps-input-to-tx1-for-line-discipline/

Anton Chulev

Hi AntonW,

GNSS_PPS pin is float in module, it can not be used as any functional pin.

Is the GNSS_PPS on B18 connected on the TX2 module and is it available for this function? The link to the post above makes the following statement.

“Bottom line is the hardware support for PPS signal is only available in the chip after Jetson TX1.”

Does this mean the TX2 supports a PPS and if it does is it supported on GNSS_PPS (B18)?

Not yet, it is float too.

Hello guys,
I am interested in getting a Pulse-per-second signal into my TX2, I know I can modify my dtb in order to introduce a pps-gpio source and so the pps-gpio module gets loaded. Is there any example of how to modify the dtb (I know already the decompilation/editing/compilation process in order to introduce the changes) using an available GPIO?.
Thank you|

Gyver

Hi Guys,

Now we have new Jetpack4.2 does the GNSS PPS b18 is enabled now?