Page Comparison

...

The following sections explain the use of INF files and GUIDs.   Table - Micrium USB Classes Concerned by Windows USB Device Management shows the USB classes to which the information in the following sub-sections applies.

About INF Files

An INF file is a setup information file that contains information used by Windows to install software and drivers for one or more devices. The INF file also contains information to store in the Windows registry. Each of the drivers provided natively with the operating system has an associated INF file stored in C:\WINDOWS\inf. For instance, when an HID or MSC device is connected to the PC, Windows enumerates the device and implicitly finds an INF file associated to an HID or MSC class that permits loading the proper driver. INF files for native drivers are called system INF files. Any new INF files provided by manufacturers for vendor-specific devices are copied into the folder C:\WINDOWS\inf. These INF files can be called vendor-specific INF files. An INF file allows Windows to load one or more drivers for a device. A driver can be native or provided by the device manufacturer.

Table - Windows Drivers Loaded for each Micrium USB Class shows the Windows driver(s) loaded for each Micrium USB class:

When a device is first connected, Windows searches for a match between the information contained in system INF files and the information retrieved from device descriptors. If there is no match, Windows asks you to provide an INF file for the connected device.

An INF file is arranged in sections whose names are surrounded by square brackets []. Each section contains one or several entries. If the entry has a predefined keyword such as “Class”, “Signature”, etc, the entry is called a directive.  presents Listing - Example of INF File Structure presents an example of an INF file structure:

; =================== Version section =====================
[Version]                                                                     (1)
Signature = "$Windows NT$"
Class     = Ports
ClassGuid = {4D36E978-E325-11CE-BFC1-08002BE10318}
 
Provider=%ProviderName%
DriverVer=01/01/2012,1.0.0.0
 
; ========== Manufacturer/Models sections =================
 
[Manufacturer]                                                                (2)
%ProviderName% = DeviceList, NTx86, NTamd64
 
[DeviceList.NTx86]                                                            (3)
%PROVIDER_CDC% = DriverInstall, USB\VID_fffe&PID_1234&MI_00
[DeviceList.NTamd64]                                                          (3)
%PROVIDER_CDC% = DriverInstall, USB\VID_fffe&PID_1234&MI_00
 
; ================ Installation sections ==================                   (4)
 
[DriverInstall]                                                 
include   = mdmcpq.inf
CopyFiles = FakeModemCopyFileSection
AddReg    = LowerFilterAddReg,SerialPropPageAddReg
 
[DriverInstall.Services]                                        
include    = mdmcpq.inf
AddService = usbser, 0x00000002, LowerFilter_Service_Inst
 
[SerialPropPageAddReg]                                          
HKR,,EnumPropPages32,,"MsPorts.dll,SerialPortPropPageProvider"
 
; ================== Strings section ====================== 
[Strings]                                                                     (5)
ProviderName = "Micrium"
PROVIDER_CDC = "Micrium CDC Device"

Refer to the MSDN online documentation on this web page for more details about INF sections and directives: http://msdn.microsoft.com/en-us/library/ff549520.aspx .

...

xxxx, yyyy, represent the value of the Device descriptor fields “idVendor” and “idProduct” respectively (refer to the Universal Serial Bus Specification, revision 2.0, section 9.6.1 for more details about the Device descriptor fields). This string allows Windows to load a driver for the device. You can modify xxxx and yyyy to match your device’s Vendor and Product IDs. In Listing - Device Configuration Template, the hardware ID defines the Vendor ID 0xFFFE and the Product ID 0x1234.

...

The [Strings] section contains a description of your device. In Listing - Example of INF File Structure, the strings define the name of the device driver package provider and the device name. You can see these device description strings in the Device Manager. For instance,   Figure - Windows Device Manager Example for a CDC Device shows a virtual COM port created with the INF file from Listing - Example of INF File Structure. The string “Micrium” appears under the “Driver Provider” name in the device properties. The string “Micrium CDC Device” appears under the “Ports” group and in the device properties dialog box.

Using GUIDs

A Globally Unique IDentifier (GUID) is a 128-bit value that uniquely identifies a class or other entity. Windows uses GUIDs for identifying two types of device classes:

...

Three of Micrium’s USB classes are provided with Visual Studio 2010 projects. These Visual Studio projects build applications that interact with a USB device. They use a device interface class GUID to detect any attached device belonging to the class.   Table - Micrium Class and Device Interface Class GUID shows the Micrium class and the corresponding device interface class GUID used in the class Visual Studio project.

The interface class GUID for the HID class is provided by Microsoft as part of system-defined device interface classes, whereas the interface class GUID for PHDC and Vendor classes have been generated with Visual Studio 2010 using the utility tool, guidgen.exe. This tool is accessible from the menu Tools and the option Create GUID or, through the command-line by selecting the menu Tools, option Visual Studio Command Prompt and by typing guidgen at the prompt.

...