Changes between Version 5 and Version 6 of Specs/I²C/Protocol

Timestamp:

09/08/13 16:03:23 (11 years ago)

Author:

ph3-der-loewe

Comment:

Info on device vendors, types, subtypes and revisions.

Specs/I²C/Protocol

@@ -57 +57 @@
 
 === Vendor ID, Device Type, Device Sub-Type, Device Revision ===
-...
+Those are information on the vendor and kind of the device.
+The vendor ID is the actual vendor of the device.
+The device type is the basic type of the device:
+||= Type =||= Symbolic name    =||= Description =||
+||0       ||GENERIC             ||This is a generic device. It only supports this Bank. ||
+||1       ||BRIDGE              ||This device interacts as bridge between at least two different physical or logical ports. ||
+||2-63    ||                    ||Reserved. ||
+||64-127  ||VENDOR00 - VENDOR63 ||Vendor specific type. Depends on the Device Vendor. ||
+
+The subtype defines the device more closely. The subtype fully depends on the type. However the value of zero should be used for the most basic kind of this type of device.
+
+For devices of type GENERIC the subtype MUST be zero.
+For devices of type BRIDGE the following subtypes are defined:
+||= Type =||= Symbolic name    =||= Description =||
+||0       ||GENERIC             ||Generic bridge device. ||
+||1       ||CONVERTER           ||Device is a simple media converter. ||
+||2-255   ||                    ||Reserved. ||
+
+The revision corresponds to the revision of the real hardware or firmware. This is mostly for informational usage but can also be used by a driver to detect the presents of an advanced feature added only to later devices of this type/subtype.
 
 === Parent Vendor ID, Parent Device Type, Parent Device Sub-Type ===
-...
+Those parameters work exactly as the Vendor, Type and Sub-Type parameters.
+They give information about the logical parent device type.
+The device has all attributes of the parent device in addition to it's own.
+The main usage of this is to allow writing drivers with some standard functionality. Those can check for the parent device attributes and use those to select a basic set of instructions how to talk to the device. This is important for Plug&Play and avoids that similar devices use completely incompatible modes of operation.
 
 === Device Status, Device Capabilities ===