Question: How does the CyUSB.dll recognize the cypress device pluged in? Does it use the PID/VID , GUID or other entry property?
Answer: Cypress .Net interface is capable of handling USB, Mass storage and HID class. So it traverses these three classes in registry and maps the DriverGUID registry entries with the corresponding Driver. Using this DriverGUID registry value only our .Net interface recognises devices. VID/PID is used to get handle to a particular device when more than one device is connected to CyUSB.sys.
In our cyusb.inf we comment out the lines
CyUsb.GUID="{AE18AA60-7F6A-11d4-97DD-00010229B959}"
and
HKR,,DriverGUID,,%CyUsb.GUID%
to imply the fact that customer should use their own GUID for production even if cyusb.sys is used without modifying.
In some releases of ours we would have not commented out these two lines. When one of these inf files is used the DriverGUID registry value is added in the registry. Which makes the device visible to the .Net interface.
