Ethernet power supply standard

michaelsmichaels New Member Posts: 4

Which Ethernet standard has the Up squared power circuit implemented? When I look at the specifications page and even search for common phrases like IEEE 802.3af, IEEE 802.3at, poe, and power over ethernet all searches conclude with no results.

Documentation

If it's impossible to power the device using common standards, please at least indicate this and offer an alternative. There is no USB-C port, so I assume some header is used as a 3,7V or 5V intake? I've searched for such information as well and only found that no battery connector exists and a JST-PH header serves to supply power to connected peripherals. It seems there is no schematic to help with such research either.

Confusion

This is really confusing! Is it possible that the only way to power the Up squared computer is through use of a large and nonportable external AC/DC converter plugged into the barrel connector? Are any of the 3V3 or 5V connectors listed on the specifications page intakes or do they all simply supply connected devices?

Request

Please list at least three ways that the Up squared computer can be powered, and recommend the best method to power in a mobile configuration.

Reverse engineering

I can create a USB-C integrated hat board if needed, but prefer to not reverse engineer the DC-in hat to find the information. I don't even think the DC-in hat authors have bothered to publish the schematics, either.

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Answers

  • nukularnukular New Member Posts: 71 ✭✭✭

    Why is this confusing? If there is nor information at all about PoE, then that should tell you that it is not supported. The Board is designed to be powered via the 5V DC jack, but Aeeon said that you can also power it via the 5V and 3V3 pins of the 40 pin header (link).
    Personally, I think that also supplying 3V3 does not make much sense, because the board would need to have a 5V to 3.3V converter on board anyway, because the "normal" way of powering the board is with only 5V. So if there is a 3V3 converter on board and now you connect a different 3V3 line in parallel to it, that might not be a good idea. Schematics sure would be nice, but unfortunately, they are not public.

    I am currently in the process of making a board that will power 2 UP2 via the 40pin header. It is not done yet, but I will report once it is done.

  • michaelsmichaels New Member Posts: 4

    That's great that you're making a power hat and it looks likely that I'll do the same, maybe including a UART to USB bridge if I can find out (lack of docs) which UARTs are accessible and how the device tree exposes them. Even if you and I create this board, it would likely only carry 1A which might not be enough in all common environments unless the two 5V hat pins are not bridged and 1A current is supplied in parallel.

    I agree that powering using both 5V and 3V3 is a bit strange, but maybe the 3V3 intake is useful for people developing battery circuits.

    The reason for confusion is that so much is not documented properly, for example whether the hat pins intend for power in or out and how much current they support. There is no schematic or other document to show diodes, ESD, fuses, or other inline part to make up for the lack of documentation. Then there is lack of specification of alternative powering and no statement about PoE so it's left up to the developer to guess what's going on.

    Take a look at the indications on lower left corner where it's essential to label the JST-PH header and the designers failed to do so:

    https://www.up-board.org/upsquared/
    https://i0.wp.com/www.up-board.org/wp-content/uploads/2017/03/UP-overview1.png?resize=1100,389

    I believe another user couldn't figure out from the documentation what the 'power pin header' means, so this led to questions answered as 'it means it is a output power header.' The good news is that the PDF datasheet is not flawed in the same way as the website documentation, so it's possible to know that the JST-PH header supplies (not accepts) power, probably 5V, as long as the datasheet was downloaded beforehand.

  • nukularnukular New Member Posts: 71 ✭✭✭

    @michaels said:Even if you and I create this board, it would likely only carry 1A which might not be enough in all common environments unless the two 5V hat pins are not bridged and 1A current is supplied in parallel.

    Can you elaborate on that? Why only 1A?

    The reason for confusion is that so much is not documented properly, for example whether the hat pins intend for power in or out and how much current they support. There is no schematic or other document to show diodes, ESD, fuses, or other inline part to make up for the lack of documentation. Then there is lack of specification of alternative powering and no statement about PoE so it's left up to the developer to guess what's going on.

    Take a look at the indications on lower left corner where it's essential to label the JST-PH header and the designers failed to do so:

    https://www.up-board.org/upsquared/
    https://i0.wp.com/www.up-board.org/wp-content/uploads/2017/03/UP-overview1.png?resize=1100,389

    I believe another user couldn't figure out from the documentation what the 'power pin header' means, so this led to questions answered as 'it means it is a output power header.' The good news is that the PDF datasheet is not flawed in the same way as the website documentation, so it's possible to know that the JST-PH header supplies (not accepts) power, probably 5V, as long as the datasheet was downloaded beforehand.

    Yes, the documentation for hardware developers could certainly be better. For the connectors there is the Connectors Description PDF that tells you which components are used and then you can look up the specifications for each connector.

    btw: The Power Pin Header in this image is not a "power output". It is a connector for a power button.
    The JST-PH header (CN10) next to it is a 5V power output e.g. for SATA devices. I would assume that it could theoretically also be used as an input, because for it to be one-way only, there would have to be a diode or something and that would probably drop the voltage too much. But these types of connectors are usually only rated for 2-3A, which could cause some problems.

  • ccaldeccalde New Member Posts: 348 admin

    Hi @michaels ,

    The network interface is RTL8111G, IEEE 802.3.
    PoE is not available as you can not see it in the hw specs.

    About the board power, you have only two ways:
    Using DC jack connector, with the ACDC converter supply,
    or, using 5V and 3V3 pins from the 40-pin connector.

    Cheers!

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