PRSNT0 and PRSNT1 signals

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

Please what is the purpose of the PRSNT0 and PRSNT1 signals? I haven’t found anything in the documentation.
Do I need to implement these signals when designing custom carrier board?

I’ve seen that this was already asked in
https://devtalk.nvidia.com/default/topic/1052060/jetson-agx-xavier/xavier-carrier-board-p2822_b02-/post/5340897/#5340897

but there was not clear answer if these signals are needed or not

Many thanks
Daniel

2

It is to prevent hot-plug, better to follow the design.

3

I’m very sorry, but I’m not sure I know how to interpret this answer:

  1. “prevent hot plug” => SoM is screwed to the carrier board so there is no chance of any hot plugging. Or was it meant differently?

  2. “follow the design” => what design? There is no description of these signals in the manual, except that they are listed in the pin list.

I would really appreciate bit more insight into the functionality of these 2 signals, so our designers can make own qualified decision how to implement it.

Many thanks
Daniel

4

There will be related description in new OEM DG doc. You can leave them unused if no hot-plug risk on your design. What we suggested is better to keep the PRSNT0 and PRSNT1 same as schematic as backup design since it is a simple circuit.

5

Ok so recomended is:

  • PRSNT0 to GND (as in carrier board design) => clear
  • PRSTN1 -The functionality of Carrier board is not clear to me, there is mechanical switch (S501) and 4k7 pull-up to 3V3 and pull-down to GND (probably not populated?). Which of this circuitry is recommended ? Is just 4k7 pull-up sufficient or do I need something more ? (we control the power-up sequence by another CPU and plan no mechanical switches in the design)

Many thanks
Daniel

6

“PRSNT0 to GND” + “PRSNT1 with 4.7k pu to 3.3v”.

7

Ok, perfect. Thx a lot for this recomendation