Teensy 3.5/3.6 Ethernet Wish List (PoE)

Okay, thanks for clarification & links!
The confusion is gone now.

Any idea when the software layer would become available?
Pcb and componets less the POE module have arrived. Putting mine together and then going to try out a copy of Espruino that ive been tinkering with for the teensy. I've also been playing with getting miniweb server working and a few other ether net things working. All very early stages.
POE ethernet design, using RJ45 with integrated Magnetics.

I was catching up on the KS comments and saw a couple pleas for PoE support and various questions/comments on the design.

I'd very much like to see 802.3af support. This means choosing a more expensive set of magnetics (either integrated jack or discrete). Certainly if I was dreaming big I'd say 802.3at (25~30 W), but most projects will easily run within the power budget of 802.3af PoE (12.95 W, yeah I know it's 15.4, but some turns to heat in the cable). Rather than reinvent the wheel I'm happy if support is provided by optionally adding a SilverTel module as suggested in the first KS comment about PoE.

The SilverTel module used on the Ardunio boards is from the Ag9000 series (http://silvertel.com/products/poe-power-over-ethernet/26-poe-modules/162-ag9000.html). The Ag-9120-S in fact, which outputs 12V by default but I believe the Arduino uses the adjustment pins to lower the voltage to 9V, perfect for the regulator on board to be powered. For Teensy I'd suggest the Ag9050-S instead and bump the output up with adjustment resistor to 5.25V, perfect for feeding 3.3V LDO and 5V for USB host or 5V peripherals (WS2812 LEDs anybody?).

The SilverTel module is super easy to use, completely passive from the microcontroller's point of view and handles the 802.3af PD (powered device) signature enabling power to be provided from the PSE (power sourcing equipment, i.e., PoE capable switch). It does require PoE compatible magnetics, center-taps on the line side of the transformers. Like the Arduino board and shield the PoE module can be made optional if the magnetics are in place with no changes needed to the rest of the environment.

<RANT>I know it's easy to argue that using a passive PoE cable adapter, splice wires in, etc should be sufficient. This is a poor solution and leads to damaged equipment when wiring mistakes are made, cables used with XYZ project are grabbed to connect a laptop, etc. The overall project appearance becomes sloppy, although some boards have had passive PoE built in - hopefully with jumper selection. Some will argue cost and that PoE switch is not a hobbyist item. Again, doing something the hacky way works fine until a mistake is made. Not all applications will be hobbyist projects. PSE cost shouldn't be a factor. Today a PoE NetGear 1gig 8port (4 w/PoE) switch (GS108PE) is $107 on Amazon, IIRC the GS108 was more when gigabit entered the home/soho market. Used enterprise switches (especially 100mb) are also affordable in the second hand market. Injectors are available sub-$20, smaller/slower switches are sub-$50. In qty 1 the magnetics are probably the bigger cost looking for a jack with PoE magnetics at digikey several years ago was depressing (think $10-$15 premium). Having 802.3af PoE capability doesn't preclude someone from using a passive adapter set.</RANT>

A true risk with PoE is square footage, looking at the photos on KS, perhaps with an integrated magnetics jack there may be just enough space to drop the module in, but I wouldn't be surprised to see the Ethernet shield end up longer or wider than the Teensy itself. This brings up a rabbit hole of the PoE capable board and Ethernet only board. At this point the non PoE board seems more attractive to design first and leave the PoE board to not get designed. Great opportunity for another builder, but probably a low quantity option, especially from a 3rd party.

Just pulled up the app note for the LAN8720A qualified/suggested magnetics, http://ww1.microchip.com/downloads/cn/AppNotes/cn562793.pdf, the only qualified PoE jack doesn't immediately appear available with 1-2 minutes of googling. So that's the other risk - finding a compatible magnetics.

Sorry for the long message, but I wanted to capture as much information initially. Can't wait to see Teensy 3.5 and 3.6. Love everything PJRC does for their customers and the community more generally. I hope I'm able to find time to test out Ethernet capability as development progresses, I stepped up my support to get in on the early Ethernet module after my initial thought of waiting for the module to be generally available.

Some years ago i did a design of a Temperature & Humidity data logger using an RJ45 connector (HY931147AE) with integrated magnetics and 2 set of Diode bridges.
The deign uses the old EN28J60, with all it's flaws, but it works quite well, it still in use every day, and connecting to the SQL server once in 15 minutes delivering the data from a local SD card.


POE ethernet on datalogger.jpg