Has anybody with done anything with usbnet? It is supported on various debian releases. With it you could have a number of BB (and BB+Kiwi) and daisy chain them with usbnet and have only one Cat5 ethernet connection.


  • On my BB-AI usebnet is already there. I need to understand more about connmand. I am hope that I can reduce betwork noise from my 4 kiwi systems this way. May be better than using wifi.

  • Rob,AI6VN, and I have looked at using Kiwi/BB in a "power-over-USB" manner in order to hopefully reduce ground loops and noise with a single OpenWRT WiFi router. While Rob has been using it with the KiWi/BB as client, using the microUSB connector on the BB and the only USB-A that existed on the router, through use of a Y cable to supply power from the USB-A port on the BB, I've been interested in using only host-host mode. That is, only a single interconnection from the Kiwi/BB to the router via a USB-A to USB-A cable.

    I don't know anything about the USBnet world but from a brief search it looks like its host-host mode might be what's needed. I made the power distribution work with a simple router modification so that it received kiwi-sourced power as well as data and allowed the KiwiSDR-to-BB_PMIC power distribution to work normally but I was not able to get both (host) sides to talk beyond satisfying ARP from the BB side. The router wanted to see a client connection and didn't so apparently couldn't/wouldn't talk the other way (except for ARP).

    I haven't looked at this for a while but am still interested in the possibility.

  • jksjks
    edited December 2020

    @N6GN How are you guys overcoming the 500 mA current limit on the 5V input of the micro-USB of the BBG? (The PMIC chip enforces this. The limit can be raised by programming an internal register using the I2C interface, but that becomes a chicken/egg problem since the Kiwi board power-up can't be delayed from the BBG).

    I haven't tried it, but one thing I think you can do is solder in the (normally depopulated) R168 zero ohm jumper that ties USB_DC and VDD_5V together. See page 2 of the BBG schematic. VDD_5V is the 5V input coming from the Kiwi board via the BBG headers and goes to the "AC" input pin on the PMIC. The AC input has a default current limit of 2.5A and the PMIC knows to preferentially select it when both USB_DC and AC input voltages are present (hence they can be shorted together by R168 and the higher current limit of the AC input applies).

  • I'm not doing any PoE or main USB feeds. Initially I just want to look into daisy chaining my 4 BBAI systems and feeding the first one with normal Cat5.

    In may be for naught as earler, when I had all four on Wifi network connectivity, I couldn't find any "noise advantage"

  • @jks I think we're dealing with it by using the 2x.5A available from the (dual output) TPS2051 sourcing the USB-A connector. Rob has built a Y cable so he could get data from the microUSB-client connector but power from the USB-A. It may be that the router is pulling even less than .5A too, I don't think I've measured it.

    I have only used the USB-A for power after searching for the location of the absent R168 and not finding it! I don't have a copy of Orcad to locate it and gave up. If someone here does and can post this using SEEDs file I'd appreciate it.

    But I think a nicer solution would be the USB-A-to-USB-A connection though since that should be capable of working, given the correct driver incantations and wouldn't require any Kiwi/BB modifications. Maybe USBnet can do this. However the router we're using needs a (simple) modification to get it to accept 5V from the USB-A which it normally tries to serve rather than receive power from.

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