sslug-teknik team mailing list archive

["Jan Hertel" <jhw100@xxxxxxxxx>]

Kristian Nørgaard skrev:

<--- klip --->

> Nu ved jeg ikke så meget om USB busser...
> - kan man f.eks. købe en skræddersyet PC, hvor kravet er at bussen
> entydigt identificerer den fysiske port?

Det kunne være at du kunne få lidt ud af at læse blandt andet
http://en.wikipedia.org/wiki/USB :

"In USB terminology a single physical USB device may consists of
several logical sub-devices that are referred to as device functions,
because each individual device may provide several functions, such as
a webcam (video device function) with a built-in microphone (audio
device function).

USB device communication is based on pipes (logical channels). Pipes
are connections from the host controller to a logical entity on the
device named an endpoint. The term endpoint is also occasionally used
to refer to the pipe. A USB device can have up to 32 active pipes, 16
into the host controller and 16 out of the controller. Each endpoint
can transfer data in one direction only, either into or out of the
device, so each pipe is uni-directional. Endpoints are grouped into
interfaces and each interface is associated with a single device
function. An exception to this is endpoint zero, which is used for
device configuration and which is not associated with any interface.

When a device is first connected, the host reads a mandatory
descriptor of the device, and loads the device driver it needs. When a
function or hub is attached to the host controller through any hub on
the bus, it is given a unique 7 bit address on the bus by the host
controller, which essentially concludes the process called
"enumeration". The host controller then polls the bus for traffic,
usually in a round-robin fashion, so no function can transfer any data
on the bus without explicit request from the host controller.",

http://www.usb.org/home , og

http://www.linux-usb.org , hvis ikke du har gjort det allerede? Google
eventuelt selv efter mere.


-- 
/Jan