search

AI6YP / eth01-evo

eth01-evo board experiments
MIT License
11 stars 0 forks source link

Is it correct that this board does NOT do POE? #1

Open skinkie opened 10 months ago

skinkie commented 10 months ago

Looking at the schema, is it correct that the board needs an external step down converter towards 5V to bring power to the board? Hence it only has POE output, but on itself, it does not power it?

TD-er commented 9 months ago

It looks like it only exposes the PIO pins and given the very unclear schematic on AliExpress it does seem to have a rectifier in the RJ45 connector.

This does make some sense as it allows to add proper isolation so it is safe to have the board connected to your computer and powered via PoE.

But I do find it kinda misleading to advertise it as PoE and not having anything on the board to actually support PoE.

Better to advertise it as "PoE-ready"

skinkie commented 9 months ago

@TD-er this is my conclusion as well. I have added a cheap component that allows passive-POE to work.

TD-er commented 9 months ago

I also looked at the DC/DC converter on the board and it seems to be the ETA3417 It can handle upto 2.5A continuous according to some screenshots from a datasheet I can't find 🙂 V_in can be upto 7V (9V absolute max) so you can't use it to directly connect it to the PoE input pins directly from a PoE switch or using passive injectors which typically are used along with 12-15V power adapters. When putting in 7V on such a passive injector, I'm afraid the voltage drop over the Ethernet cable will be too much. So you really need some external PoE module like the 9400 or something similar. (the 9400 is a really good one by the way)

skinkie commented 9 months ago

So you really need some external PoE module like the 9400 or something similar. (the 9400 is a really good one by the way)

Can you elaborate if that would work on just the two available POE pins? (I mean does it require anything extra for negotiation?)

TD-er commented 9 months ago

I have not tried that specific module myself on this board. But I have used those modules in the past to add PoE to some board I designed myself.

See RT9400 datasheet I'm not 100% sure if the diodes in the phy will cause issues here.

TD-er commented 9 months ago

Part of how I used that RT9400 in my own board design:

image

Datasheet of the phy I used: https://nl.mouser.com/datasheet/2/3/ARJM11-1775072.pdf image

skinkie commented 9 months ago

I don't see how on the EVO the RX/TX are available on pins.

TD-er commented 9 months ago

See the connector layout as posted in this repo: image

The V+ is then the combined VC1+ and VC2+ of the connector I used. N.B. J1 ... J8 are in a different order but seem to refer to the same signals on the RJ45 connector.

As I already mentioned, I'm not sure whether the diodes may cause issues for negotiations with the PoE switch/injector. Also not sure if for this board the VA1 and VB1 should be connected on the RT9400 (and the same for the VA2 and VB2)

guyeeba commented 6 months ago

There is a daughterboard available on AliExpress that makes the ETH01-EVO POE capable: https://www.aliexpress.com/item/1005006598094055.html

It works perfectly, but be very careful, NEVER try to flash the board with POE ethernet connected, otherwise bad things happen! Only one power source can be used at any time! Power the board from the USB/serial adapter and use non-POE ethernet, or use POE, but disconnect the power pin from the adapter.

skinkie commented 6 months ago

There is a daughterboard available on AliExpress that makes the ETH01-EVO POE capable:

Kind of pricy...