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

09/08/13 16:03:23 (6 years ago)

Info on device vendors, types, subtypes and revisions.


  • Specs/I²C/Protocol

    v5 v6  
    5858=== Vendor ID, Device Type, Device Sub-Type, Device Revision === 
    59 ... 
     59Those are information on the vendor and kind of the device. 
     60The vendor ID is the actual vendor of the device. 
     61The device type is the basic type of the device: 
     62||= Type =||= Symbolic name    =||= Description =|| 
     63||0       ||GENERIC             ||This is a generic device. It only supports this Bank. || 
     64||1       ||BRIDGE              ||This device interacts as bridge between at least two different physical or logical ports. || 
     65||2-63    ||                    ||Reserved. || 
     66||64-127  ||VENDOR00 - VENDOR63 ||Vendor specific type. Depends on the Device Vendor. || 
     68The 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. 
     70For devices of type GENERIC the subtype MUST be zero. 
     71For devices of type BRIDGE the following subtypes are defined: 
     72||= Type =||= Symbolic name    =||= Description =|| 
     73||0       ||GENERIC             ||Generic bridge device. || 
     74||1       ||CONVERTER           ||Device is a simple media converter. || 
     75||2-255   ||                    ||Reserved. || 
     77The 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. 
    6179=== Parent Vendor ID, Parent Device Type, Parent Device Sub-Type === 
    62 ... 
     80Those parameters work exactly as the Vendor, Type and Sub-Type parameters. 
     81They give information about the logical parent device type. 
     82The device has all attributes of the parent device in addition to it's own. 
     83The 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. 
    6485=== Device Status, Device Capabilities ===