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skrzyp |
<!-- Copyright (C) 2001 Free Software Foundation, Inc. -->
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<!-- This material may be distributed only subject to the terms -->
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<!-- and conditions set forth in the Open Publication License, v1.0 -->
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<!-- copyright holder. -->
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<!-- standard (paper) book form is prohibited unless prior -->
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<!-- permission is obtained from the copyright holder. -->
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<HTML
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><HEAD
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><TITLE
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>Network Device for the eCos TCP/IP Stack</TITLE
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><META
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NAME="GENERATOR"
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CONTENT="Modular DocBook HTML Stylesheet Version 1.64
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"><LINK
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REL="HOME"
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TITLE="eCos Support for Developing USB-ethernet Peripherals"
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HREF="io-usb-slave-eth.html"><LINK
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REL="PREVIOUS"
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TITLE="USB-ethernet State Handling"
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HREF="usbseth-control.html"><LINK
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REL="NEXT"
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TITLE="Example Host-side Device Driver"
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HREF="usbseth-host.html"></HEAD
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><BODY
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CLASS="REFENTRY"
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BGCOLOR="#FFFFFF"
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VLINK="#840084"
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><DIV
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><TABLE
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CELLSPACING="0"
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><TR
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><TH
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COLSPAN="3"
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ALIGN="center"
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>eCos Support for Developing USB-ethernet Peripherals</TH
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></TR
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><TR
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><TD
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WIDTH="10%"
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ALIGN="left"
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VALIGN="bottom"
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><A
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HREF="usbseth-control.html"
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>Prev</A
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></TD
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><TD
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WIDTH="80%"
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ALIGN="center"
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VALIGN="bottom"
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></TD
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><TD
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WIDTH="10%"
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ALIGN="right"
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VALIGN="bottom"
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><A
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HREF="usbseth-host.html"
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>Next</A
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></TD
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></TR
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></TABLE
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><HR
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ALIGN="LEFT"
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WIDTH="100%"></DIV
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><H1
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><A
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NAME="USBSETH-NETDEV"
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>Network Device for the eCos TCP/IP Stack</A
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></H1
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><DIV
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CLASS="REFNAMEDIV"
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><A
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NAME="AEN221"
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></A
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><H2
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>Name</H2
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>Network Device -- USB-ethernet support for the eCos TCP/IP Stack</DIV
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><DIV
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CLASS="REFSECT1"
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><A
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NAME="AEN224"
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></A
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><H2
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>Description</H2
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><P
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>If the USB peripheral involves running the eCos TCP/IP stack and that
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stack needs to use USB-ethernet as a transport layer (or as one of the
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transports), then the USB-ethernet package can provide a suitable
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network device driver. It is still necessary for higher-level code to
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perform appropriate initialization by calling <A
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HREF="usbseth-init.html"
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><TT
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CLASS="FUNCTION"
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>usbs_eth_init</TT
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></A
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>, but
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after that it will be the TCP/IP stack rather than application code
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that transmits or receives ethernet frames.</P
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><P
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>Not all peripherals involving the USB-ethernet package will require a
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TCP/IP stack. Hence the provision of the network device is controlled
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by a configuration option <TT
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CLASS="LITERAL"
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>CYGPKG_USBS_ETHDRV</TT
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>. By
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default this will be enabled if the TCP/IP package
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<TT
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CLASS="LITERAL"
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>CYGPKG_NET</TT
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> is loaded, and disabled otherwise. </P
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><P
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>There are a number of other configuration options related to the
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network device. <TT
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CLASS="LITERAL"
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>CYGFUN_USBS_ETHDRV_STATISTICS</TT
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>
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determines whether or not the package will maintain statistics, mainly
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intended for SNMP: by default this will be enabled if the SNMP support
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package <TT
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CLASS="LITERAL"
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>CYGPKG_SNMPAGENT</TT
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> is loaded, and disabled
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otherwise. The name of the ethernet device is controlled by
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<TT
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CLASS="LITERAL"
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>CYGDATA_USBS_ETHDRV_NAME</TT
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>, and has a default value
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of either <TT
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CLASS="LITERAL"
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>eth0</TT
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> or <TT
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CLASS="LITERAL"
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>eth1</TT
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>
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depending on whether or not there is another network device driver
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present in the configuration.</P
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><P
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>Usually eCos network device drivers default to using DHCP for
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obtaining necessary information such as IP addresses. This is not
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appropriate for USB-ethernet devices. On the host-side the
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USB-ethernet network device will not exist until the USB peripheral
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has been plugged in and communication has been established. Therefore
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any DHCP daemon on the host would not be listening on that network
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device at the point that eCos requests its IP and other information. A
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related issue is that the use of DHCP would imply the presence of a
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DHCP daemon on every affected host machine, as opposed to a single
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daemon (plus backups) for the network as a whole. For these reasons
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the USB-ethernet package precludes the use of DHCP as a way of setting
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the IP address, instead requiring alternatives such as manual
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configuration.</P
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></DIV
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><DIV
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CLASS="NAVFOOTER"
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><HR
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ALIGN="LEFT"
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WIDTH="100%"><TABLE
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WIDTH="100%"
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BORDER="0"
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CELLPADDING="0"
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CELLSPACING="0"
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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><A
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HREF="usbseth-control.html"
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>Prev</A
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></TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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><A
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HREF="io-usb-slave-eth.html"
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>Home</A
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></TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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><A
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HREF="usbseth-host.html"
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>Next</A
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></TD
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></TR
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><TR
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><TD
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WIDTH="33%"
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ALIGN="left"
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VALIGN="top"
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>USB-ethernet State Handling</TD
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><TD
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WIDTH="34%"
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ALIGN="center"
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VALIGN="top"
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> </TD
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><TD
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WIDTH="33%"
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ALIGN="right"
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VALIGN="top"
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>Example Host-side Device Driver</TD
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></TR
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></TABLE
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></DIV
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></BODY
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></HTML
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>
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