Orin AGX industrial : PRSNT pins @3.3V?

Robotics & Edge Computing Jetson Systems Jetson AGX Orin
1

Hi,
On the Jetson Orin AGX Industrial (and non industrial), there are too pins labeled PRSNT0/GND_LOOP_0 (pin A3) and PRSNT1/GND_LOOP_1 (pin L63).

In the devikit, PRSNT0 is connected to GND, and PRSNT1 has a pullup to 3.3V and is used to sense if the module is present, resulting in a logic low if the module is present.

I would rather use the oposit : connect one of the pins to 3.3V directly, and put a pull down on the other pin, in order to get an active high signal. Is this permitted (ie having both PRSNT pins at 3.3V durring normal operation)?

And what is the maximum permitted current (it would be nice to add an indicator LED)

Thanks a lot in advance

2

*** Please note that this reply is generated by LLM automatically ***

The question is about the Jetson AGX Orin Industrial and non-industrial modules, specifically the PRSNT0 and PRSNT1 pins. These pins are used to sense the presence of the module, with PRSNT0 connected to GND and PRSNT1 having a pull-up to 3.3V in the devkit.

The user wants to know if it’s permitted to use the opposite configuration, where one of the pins is connected to 3.3V directly and the other pin has a pull-down, resulting in an active high signal.

According to the documentation, there is no explicit mention of the maximum permitted current for the PRSNT pins. However, it’s generally recommended to keep the current low to avoid overheating or damaging the module.

In terms of the configuration, it’s possible to use the opposite configuration, but it’s essential to ensure that the voltage levels are compatible with the module’s specifications. The Jetson AGX Orin module has a maximum voltage rating of 3.3V for the PRSNT pins.

To achieve an active high signal, the user can connect one of the PRSNT pins to 3.3V directly and add a pull-down resistor to the other pin. The value of the pull-down resistor should be chosen to ensure that the voltage level is below the threshold for the module’s presence detection.

It’s also possible to add an indicator LED to the circuit, but it’s crucial to ensure that the LED’s current consumption is within the module’s specifications.

In comparison to the Jetson Xavier NX and Jetson Orin NX/Nano modules, the PRSNT pins are not explicitly mentioned in the documentation. However, the general principles of presence detection and voltage levels apply to all modules.

To summarize:

  • The Jetson AGX Orin Industrial and non-industrial modules have PRSNT0 and PRSNT1 pins for presence detection.
  • The user can use the opposite configuration, with one pin connected to 3.3V and the other pin having a pull-down, to achieve an active high signal.
  • The maximum permitted current for the PRSNT pins is not explicitly mentioned, but it’s recommended to keep the current low.
  • The user can add an indicator LED to the circuit, but it’s essential to ensure that the LED’s current consumption is within the module’s specifications.

It’s always recommended to consult the official documentation and seek guidance from NVIDIA support before making any modifications to the module’s configuration.

*** Please give the thumbs up if you get answers you like. Or provide feedback to help us improve the answer. ***

3

Could you please add a human written (or at least human controlled) answer?

LLM by definition generate likely content, but without any regard to veracity. So as I’m asking for something that seems likely to work, having a confirmation by a LLM is useless excepted when providing links to reliable sources, which is non the case in this answer. Or if Nvidia accepts to take full responsability for all financial losses resulting from wrong information provided by LLM.

So please, provide human written (or verified) answers.
Thanks a lot in advance
Best regards,
Félix

5

NVIDIA has not tested the use of the PRSNT pins in any other way than as shown in the carrier board reference schematics and there is no specification available for the current. Note that changing the normal level of PRSNT would affect the Button MCU if you implement it on your carrier.

6

Hi,

I’m planning to implement my own MCU (I’m not planning to use any button, but power sequencing seems too complex to handle without MCU, and I got no support when asking for a non MCU solution).

As to my question about the PRSNT voltage level and current, it’s very easy to answer for anyone having access to the design files of the SoM’s PCB (which is not public as far as I know) :

  • if there is nothing else connected to the 2 PRSNT pins, then it’s not an issue to use any other voltage (withing the wistanding voltage of PCB isolation, but that’s certain to be tens of volts at least)
  • if in addition you could look at the layout of the trace connecting those 2 pins, and get the width of the trace, then I can easely do the calculations for the maximum current (there are plenty of calculators online).

It is, however, nearly impossible to get the answer without “inside” information (the only solution beeing a complete, layer by layer teardown of a module in order to do retro-engineering, which is ways too much work)

Information I’m asking you should take less than 5 minutes to answer by an electronics engineer having access to the PCB design of the Jetson Orin AGX Industrial (or at least, answering a similar question on one of our designs would take me 5 minutes, and I have no reason to believe that it would take longer to your engineers).

Thanks a lot in advance
Best Regards,
Felix

7

The two PRSNT pins are directly connected.

Layout information of the module cannot be shared.

8

Thanks. If they are connected (and not connected to anything else), then it should do safe to connect whatever voltage (within breakdown voltage of isolation).

As for current, if taking a very conservative estimate (0.5oz copper, 1mil trace), then it gives already 50mA for a 10°C temperature rise

9

There is a MODULE_SLEEP_N signal that when high indicates that the module is active, if you can use that instead of the PRSNT pins for your desired application.

image

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