Reply Device Topology - Kramer KDS-USB2 User Manual

Kramer Electronics Ltd.

3.10 Reply Device Topology

Sent by a ENCODER device in response to a Request Device Topology message. This message is of
variable length depending on the number of devices that are in the system. The combination of the
information is enough for a client to build and display a device tree.
3.10.1 Field Descriptions
USB Address
USB Address Of Parent
Port On Parent
Is Device A Hub
USB Vendor Id
USB Product Id
Byte Offset
+-----------------------------------------+-----------------------------------------+
0 | Magic Number
+
2 |
+-----------------------------------------+-----------------------------------------+
4 | Message ID
+
6 |
+-----------------------------------------+-----------------------------------------+
8 | Protocol Version = 3
+--> +-----------------------------------------+-----------------------------------------+
| 10 | USB Address
| +-----------------------------------------+-----------------------------------------+
| 12 | Port On Parent
| +-----------------------------------------+-----------------------------------------+
| | USB Vendor Id
| +-----------------------------------------------------------------------------------+
| | USB Product Id
+--> +-----------------------------------------------------------------------------------+
|
+--- Repeated 0 to MAX_USB_DEVICES(= 32) times
SwitchableUSB – 3
An integer from 0 to 127.
An integer from 1 to 127. If a USB Address is seen which is not listed as
the USB Address Of Parent for any of the devices, then that device is
the root of the device topology.
An integer from 1 to 127. 0 is not a valid number for a port on a hub, so
this field will only be 0 if there is no USB device upstream before the
host.
0=FALSE, 1=TRUE
The USB vendor id from the device descriptor.
The USB product id from the device descriptor.
Supported Messages
| Command = 5
| USB Address Of Parent
| Is Device A Hub
|
+
|
|
+
|
|
|
|
|
|
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