I thought that the USB bus was a Star Topology?

 

The devices on the USB bus are physically connected to the host via a tiered, star topology which looks like a tree.

http://www.usblyzer.com/usb-topology.htm


Regards, Dana.

 

But on this board, all the D+'s are connected together and all the D-'s are connected together.
There is no "chip select" and no controller chip? How is the up-stream device arbitrating between the four connectors.
Or should I only use one at a time?

 

How else do you think they should be wired? You're right -- there is no chip select. It is all done within the USB protocol which can use, but does not require, a separate controller. More than likely it is embedded in another chip on the other side of the physical layer interface. You should get the spec and read it for further understanding.

 

But on this board, all the D+'s are connected together and all the D-'s are connected together.
There is no "chip select" and no controller chip? How is the up-stream device arbitrating between the four connectors.
Or should I only use one at a time?

You're 100% correct. With all the D's connected you could only run one device at a time on that POS.

USB needs a hub for multiple devices, the basic communication is between two and only two devices. A hub is needed to connect to multiple things.

It may work as a charger. May not. I would not use it.