OXCFU950_07 Datasheet, PDF (65/74 Pages) Oxford Semiconductor – USB/UART multi-function 16-bit PC Card device

OXFORD SEMICONDUCTOR, INC.
OXCFU950 DATA SHEET
11 INTRODUCTION TO THE OXCFU950 SOFTWARE DRIVERS
This section gives a brief overview of the organization and usage of software drivers for the OXCFU950 operating in the
Microsoft Windows XP^TM environment.
The following figure illustrates the driver stack that is created in Windows XP for the OXCFU950 drivers. Once the device is
inserted, the PCMCIA bus driver (pcmcia.sys) drives Multi-Function driver (mf.sys), and it loads both the UART(oxser.sys) and
USB (oxcfu950.sys) driver.
4
USB client driver
Application/
Device Driver
3
USB driver
oxcfu950.sys
UART
Serial Bus Driver
oxser.sys
Multifunction bus
2
driver
mf.sys
PCMCIA bus driver
1
pcmcia.sys
Key
Oxford
Semiconductor
Driver
System
Supplied Driver
Figure 1.1 OXCFU950 Driver Stack on Windows XP
Starting from the bottom of the figure, the following describes each driver in the stack:
1. At the bottom of the driver stack tree is the PCMCIA driver pcmcia.sys which is a built-in driver of Windows XP. The
PCMCIA driver, pcmcia.sys detects the OXCFU950 device when the card is inserted, and reports the device details
described in attribute memory in the OXCFU950. Because the OXCFU950 complies with the PC Card multifunction
standard, the Multi-Function driver, mf.sys is automatically loaded after PCMCIA 16-bit PC Card or CompactFlash/
CF+card is inserted.
2. The Multi-Function driver, mf.sys allows both functions to communicate with the hardware independently and defines a
range of I/O resources that are exclusive to each function. Once the mf.sys is loaded by pcmcia.sys, mf.sys
enumerates the functions such as Device 0 (which is the UART Port), and the Device1(which is the USB Controller)
and thereby causes the Plug and Play (PnP) Manager to load individual function drivers. mf.sys is installed by the
system supplied inf file, mf.inf.
3. The Multi-function driver, mf.sys enables the individual device drivers to access individual hardware resources without
any interaction with each other. The OXCFU950 is driven by two individual drivers, The UART port is driven by the
oxser.sys and the USB port is driven by the oxcfu950.sys.
The UART driver oxser.sys has an interface compatible with built-in Microsoft COM port driver, serial.sys, and the USB
driver oxcfu950.sys has an interface compatible with built-in Microsoft USB driver, usbhub.sys. The drivers at level 4 in
the diagram can access the supplied Oxford Semiconductor driver using the same I/O request codes that are used for
the built in Microsoft equivalents.
DS-0023 February 2007
External—Free Release
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