Programming Interface

The USBHub3+ is capable of many features. These features are organized into groups called entities. Through these entities we can access the vast features of the USBHub3+.

A complete list of all entities and functions can be found in the Module Module Entities page.

Software Control

Software control of the features of the USBHub3+ is done with the BrainStem API via a BrainStem link. BrainStem links are done over USB and can be established via upstream port 0 (Up0), upstream port 1 (Up1), or the Control Port. After one or more of these ports is connected to a host machine, a user can connect to it via software API:

When multiple Acroname devices are connected to a host, connecting to a specific hub can be done by providing the hub serial number. Further, all connected devices can be found using (Python)
Acroname::BrainStem::Link::sDiscover() (C++)

BrainStem Control Port

The USBHub3+ also has a dedicated control channel on the USB mini-B connector. This is a full-speed USB 2.0 connection for BrainStem interface only. No USB hub traffic can flow on this connection. When a cable is connected to the mini-B connector, the BrainStem link can only be established through the Control Port, independent of the selected upstream port. The USB 3.0 type-B connectors are then used only for USB hub traffic to connect downstream USB devices. When the Control Port is not used, the BrainStem link will share the active upstream USB connection. Using the Control Port provides the ability to completely disconnect both USB upstream host connections while maintaining sofware control of the hub.

Using Multiple Hosts with USBHub3+

The two upstream-facing host ports can be connected to two different host computers. The control port can be attached to no computer, one of the same computers attached to the upstream ports, or a third host computer. Due to limitations of USB specification, only one host computer can access downstream USB ports at any time. Through the BrainStem API, the upstream port used can be controlled, or the system can automatically select the upstream port (see USB Hub Upstream Mode). When automatically selecting the upstream port, the USBHub3+ will favor using Up0 if it is connected.

Device Drivers

The USBHub3+ leverages operating system user space interfaces that do not require custom drivers for operation on modern operating systems.

Some older operating systems may require the installation of a BrainStem USB driver to enable software control. Installation details on installing USB drivers can be found within the BrainStem Development Kit under the “drivers” folder. For example, Windows 7 requires the supplied INF to communicate with BrainStem USB devices.