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Preliminary User Guide, Rev. 2 USS-720
February 1999 USB Device Driver
Lucent Technologies Inc. 7-3
13
2 Initialization
■ The driver entry routine is called and initializes callbacks for the following functions when the operating system
loads the driver:
— Create: Open a handle to a device instance.
— Read: Read a block of data from the Bulk In pipe.
— Write: Write a block of data to the Bulk Out pipe.
— DeviceIoControl: Process I/O requests documented in Section 4 of this document.
— Close: Close the handle of the device instance.
■ A symbolic link will be created associating this device driver with a special device instance that can be used to
call IOCTL_GET_DEVICE_INSTANCES (i.e., LPTUSB). (See Section 4.13 of this document.)
■ The Add_Device routine is called by the configuration manager. The configuration manager interacts with the
USB bus enumerator to identify newly attached devices in the system. Through the layered driver architecture
with the host controller driver, this USS-720 routine will be called when a USS-720 device is identified. After the
device object has been successfully created, symbolic links will be created associating this device driver with the
specific device instances (i.e., LPTUSB1, LPTUSB2, LPTUSBx).
3 I/O File Functions
This section provides instructions on how to use the I/O file functions to interface with the USS-720. Only parame-
ters relative to the USS-720 Device Driver are explained in this document. Please refer to the
Win32 SDK
docu-
mentation for the complete definitions of the following functions and all referenced data types:
Function Description
CreateFile Open an instance of a particular device.
ReadFile Reads data from the Bulk In pipe.
WriteFile Write data to the Bulk Out pipe.
DeviceIoControl Send a control code to a device instance.
CloseHandle Close an instance of a device.