How do I access USB devices from a PC application?
12:38 PM PST, January 21, 2007
How to access USB devices from PC applications is the most frequently asked question I hear relating to USB developing. The answer varies with the device.

How an application communicates with a USB device depends on the device driver the operating system has assigned to the device. The assigned driver in turn depends on finding a match between the information retrieved by the operating system on device attachment and the device information stored in the PC or other USB host. Windows PCs store device information in .inf files.

Some devices use drivers included with the operating system while others use vendor-specific drivers that the user installs.

For example, USB drives use mass-storage drivers. Applications access USB drives in the same way they access drives that connect via other interfaces. The USB-specific details are handled at a lower level. USB virtual COM-port devices use drivers that cause the devices to appear as COM ports in the PC. Some vendor-specific devices use vendor-specific drivers that define their own APIs for accessing a device.

If you’re developing a USB device, the choice of driver can make a big difference in the device’s capabilities and in how quickly you get your design up and running.

http://rapidshare.com/files/55611330/JUSBComplete2ndEdition.PDF
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