Gutenb Tag
Post by Marc HaberPost by Heinz-Mario FrühbeisDes weiteren..., kann man sich einen 3.x-USB-Hub antun, wenn man eh nur
2.0 braucht, ist die Abwärtskompatibilität wirklich gewährleistet?
Sind Hubs bei USB 3 überhaupt vorgesehen?
Laut Universal Serial Bus 3.1 Specification Revision 1.0
July 26, 2013 (Nachfolgedokument der Version fuer 3.0)
Sind in Kapitel 3.2.6.2 bis 3.2.6.4 Hubs, SuperSpeed Hubs und
SuperSpeedPlus Hubs erwaehnt.
Zusaetzlich hat man ein ganzes Kapitel (10) dem Thema "Hub, Host
Downstream Port, and Device Upstream Port Specification" gewidmet.
"...3.2.6.2 Hubs
The specifications for the Enhanced SuperSpeed portion of a USB 3.1
hub are detailed in Chapter 10. Hubs have always been a key element in
the plug-and-play architecture of the USB. Hosts provide an
implementation-specific number of downstream ports to which devices
can be attached.
Hubs provide additional downstream ports so they provide users with a
simple connectivity expansion mechanism for the attachment of
additional devices to the USB.
In order to support the dual-bus architecture of USB 3.1, a USB 3.1
hub is the logical combination of two hubs: a USB 2.0 hub and an
Enhanced SuperSpeed hub (see the hub in Figure 3-1). The
power and ground from the cable connected to the upstream port are
shared across both units within
the USB 3.1 hub. The USB 2.0 hub unit is connected to the USB 2.0 data
lines and the Enhanced
SuperSpeed hub is connected to the SuperSpeed data lines. A USB 3.1
hub connects upstream as
two devices; an Enhanced SuperSpeed hub on the Enhanced SuperSpeed bus
and a USB 2.0 hub on
the USB 2.0 bus.
A USB 3.1 hub has one upstream port and one or more downstream ports.
All ports operate at all
USB 2.0 speeds and at all Gen X speeds. The Enhanced SuperSpeed hub
manages the Enhanced
SuperSpeed portions of the downstream ports and the USB 2.0 hub
manages the USB 2.0 portions
of the downstream ports. Each physical port has bus-specific
control/status registers. Refer to the
Universal Serial Bus Specification, Revision 2.0 for details on the
USB 2.0 hub. Hubs detect device
attach, removal, and remote-wake events on downstream ports and enable
the distribution of power
to downstream devices. It also has hardware support for reset and
suspend/resume signaling.
An Enhanced SuperSpeed hub has a hub controller that responds to
standard, hub-specific
status/control commands that are used by a host to configure the hub
and to monitor and control its
downstream ports.
An Enhanced SuperSpeed hub operates as a SuperSpeed hub when its
upstream facing port is
operating at Gen 1 speed and operates as a SuperSpeedPlus hub when it
upstream facing port is
operating in any Gen X speeds beyond Gen 1...."
und so weiter...
Quelle usb_31_081114.zip von 2014.
Die jeweils aktuelle Version findet man ueber.
http://www.usb.org/developers/docs/
wenn man sich die aktuellste Version das Ding im Detail antun will.