Powering Jetson Nano thru Cisco PoE+ Switch

Autonomous Machines Jetson & Embedded Systems Jetson Nano
1

How am I suppose to wire the PoE to the GPIO to power the unit with my PoE switch?

Are they any documents that I can follow?

2

I believe it works vice versa:
nano can power something over the LAN,
but may be some other folks who know for certain will respond.

3

PoE typically provides 48V DC, however Jetson Nano needs 5V input. Hence a PoE hat or step-down voltage regulator is needed to convert the 48V source to 5V. The 48V source gets routed from the Ethernet port to the J38 header, and then the 5V is supplied on pins 2/4 of J41 header.

The Raspberry Pi PoE Hat is footprint compatible with these headers, however be aware that in our preliminary testing we found that this particular PoE hat may have issues with supplying initial low-power at bootup and meeting higher power requirements depending on workload and the peripherals attached. Alternatively, you can wire in your own 48V->5V voltage regulator to the headers.

4

Hi. I am having trouble powering the nano (with RPi PoE hat) using a Cisco PoE+ switch. I’m 99% sure the problem is with power-on negotiation the switch does with the device. Here’s why I’m sure it’s the negotiation:

  1. When using a PoE injector that supplies 48v immediately without negotiation, the nano/RPi hat combo works flawlessly.
  2. When powering the nano with a 3A USB power supply, the nano/RPi hat works flawlessly.
  3. The RPi hat documentation says it is a class 2 device but the class resistor is class 3 (full 15.4W power)
  4. I even replaced the resistor on the hat to make it a class 0 device, but still does not work with the Cisco switch
  5. I have another PoE+ switch (OpenMesh SL8-L) that does the same thing as the Cisco switch

Any help anyone could provide would be greatly appreciated.

5

I can’t seem to find a pinout of j38 - there is no info in the manual.

6

Not sure if this is what you are looking for:

7

Hi,

I’ve never used POE/POE+ before, so my question deals with “Jetson nano/POE for dummies”

Our current project includes at least 4 clusters of 8 Jetson nano modules each, each cluster should be autonomous of the others (not into the same labs but into the same building).

My first idea to optimize number of PDU, and power cable requirements (that I will name the Spaghetti optimization procedure) is to use a core/edge architecture with POE/POE+ features:

  • Edge switches: 4 POE/POE+ switches of 8 POE/POE+ ports each
  • Core switch: a STD 8-12 SFP switch @1-10 Gbs to federate everything and future extension.

The short listed shoping list for edge switches set choice on NETGEAR: GC510PP as this model is 8 POE/POE+ ports @ 1Gbs and has also 2 SFP @ 1Gbs, it is up to 195W PoE power, with the flexibility to add power-hungry devices (30W max per port), advanced per-port PoE controls (set specific power budget per port in addition to automatic class defined) and PoE scheduling on PoE models (these specifications are extract from Netgear documentation, I’ve never tested them).

Let go back to my questions:

  • Q1) What do I need to complete the hardware shopping list relative to power?
  • Q2) can I connect directly Jetson Nano to POE+ ports of the GC510PP switch thru ethernet/POE+ certified cable,
  • Q3) do I need to use HAT, voltage reduction, or some extras hardware etc?

Please help me, this part is not my natural expertise domain, I need a Jetson translate or Nano assistant :-)

link to Netgear PDF click here

Sincerely,

Fred.

8

So please help me make sure I have this right. You advertise that the Nano Dev Board is PoE but it doesn’t actually run off of PoE without purchasing additional hardware? We didn’t you just add a 5V regulator to the board and limit the jumper functionality to simply dis/enabling the PoE functionality. Sorry, but it seems a bit cheesy, but this is really no better than just using a PoE hat on a Pi and the Nano is a competitor to the Pi maker market. Please advise as documentation in this area is a bit light, comparatively.

9

Hi,

Please open a new topic for this issue. Thanks

10

Forget about the Pi’s PoE hat. It is inadequate for the Nano. Amazon and others have a PoE to 5V adaptor that’s better suited for the nano made by UCTRONICS for about $30. It’s 802.3af/at compliant, and offers micro-USB, USB-C, and barrel jack pigtails for running a variety of SBCs. If you’re willing to wait for shipping from China, there’s a knockoff for about $20 on eBay that only includes the barrel jack.