Dragboard 410c usb mode


#1

Dragonboard 410c hardware manual states:

Please note: the board can work in one mode at a time, Host mode or Device mode, not both.

so is it hardware limitation or firmware limitation? Is it possible to find a solution support both mode at the same time?


#2

Hi.
The HW supports only one USB connection either device or host mode. Host mode can be equipped with USB hub to connect multiple devices.
Thanks.


#3

Hi ce1,

Thanks for the reply. We are looking a solution(hardware or firmware) to support USB both host and device mode on dragonboard 410c.

  1. Plug in PC for charging / file transfer (as slave)
  2. Plug a mouse in the USB (as master).

Do you mean for hardware limitation , it’s impossible?

Thanks,


#4

Hi @xiuge,

Unfortunately yes this is a hardware limitation so it’s impossible. Internally, there’s only 1 usb interface.


#5

Hi vchone,

Thanks for the reply. Yes, there is only one USB interface. Thinking is it possible to use some GPIO or other method to detect the board USB is plugged in PC or a mouse/sd card plug in, then change the USB working mode dynamically?

Thanks


#6

You’re welcome. It sort of already does that. To use your terminology, if plug in pc, use as slave. If plug a mouse, use as master. If plug in both, I think it defaults to slave, so things like mouse will not work. Or it might be the other way round, default to master? Anyway, in either case, it cannot work in both modes at the same time, which is what you need, right?


#7

Hi vchong,

Thanks for the clarification. :slight_smile:


#8

You can’t run both at once but IIRC the switch is under software control. By default the switch will select USB OTG if the cable is present but the switch is hooked up to a GPIO line on the PMIC which allows this to be overridden a force adoption of the type A connectors. However I don’t think you can detect devices on the type A connectors without doing a speculative switch.