Microsoft Windows CE 3.0  

USB Connectivity

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USB offers a reliable, high-speed alternative to a standard serial port for connecting a Windows CE-based platform to a desktop computer. Windows CE 2.10 and 2.12, however, could not support USB connectivity to desktop systems, unless an OEM implemented that functionality.

Windows CE 3.0 and later, however, do offer connectivity through USB. Windows CE 3.0 and later provide a USB Function controller driver for Windows CE-based platforms that include the appropriate USB Function controller hardware. By means of this driver, the USB Function controller hardware appears to Windows CE as a virtual serial port. Similarly, the desktop computer must have a similar host-side USB serial driver. With the Windows CE-based platform and the desktop computer so configured, the standard serial-port based mechanisms for connectivity can be used over a USB connection. OEMs can find the files necessary for implementing USB connectivity in the platform\cepc\drivers\serial_sl11\directory of their Microsoft Windows CE Platform Builder installations. These files support the Scanlogic Corporation's SL11 USB Function controller chipset. For complete information on implementing a virtual serial port via USB on a Windows CE-based platform, see Sample USB Function Controller Driver.

There is, however, still no support for making a Windows CE–based platform itself appear as a USB peripheral to other host computers. This is because Windows CE only implements the host side of the USB client/host architecture. That is, the HCD and USBD modules supplied in Windows CE do not provide facilities to connect a Windows CE–based platform to a desktop computer that is running as a USB host. An OEM could implement this functionality if desired, although, as with the above connectivity scenarios, the Windows CE-based platform would still require USB Function controller hardware.

 Last updated on Tuesday, July 13, 2004

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