The USBXpress development kit provides a complete host and device software solution for interfacing CP210x USB to UART bridge and C8051F32x/34x/38x and C8051T62x.T32x USB microcontroller devices to the Universal Serial Bus (USB). Silicon Labs makes USB easy: no USB protocol or host device driver expertise required.
v3.5 [Aug 3, 2010]
Development kit includes everything you need to get started:
Windows device drivers
INF driver installation files
Host API - host function library provided in Windows Dynamic Link Library (DLL) format
Device API - device firmware interface function library