Design of virtual instrument based on USB bus and LabVIEW

The technology of virtual instrument and USB interface has been paid special attention in (instrument) design and development.The intellectual peripheral which adopting USB interface for data (acquisition) and control improves the bottleneck phenomenon of the communication,and strengthens (″affinity″) of it with general computer too.General single-chip microcomputer MCS-51 provides no USB (interface).As an application software development platform of virtual instrument,LabVIEW also doesn′t (offer) USB driver of interface too.This paper introduces the design principle of virtual instruments based on USB and LabVIEW briefly.A kind of simple and feasible scheme are put forward,the course of utilizing FT245?BM to develop USB is explained,circuit diagram of the interface between FT245?BM and AVR (single-chip) AT90S1200 are given,and program is offered.The approach to program with LabVIEW while installing two kinds of USB drivers are described and the LabVIEW application program is also given.These programs have been debugged,and the test results are provided.