This paper designs a Colorimeter instrument with C8051F020 single-chip microcomputer as the processor and dual-mode USB as the interface. The instrument can work in two modes of USB device and host. In device mode, it can directly communicate with the computer; in host mode, it can read and write U disk, and transmit data through U disk. The instrument adopts dual USB sockets, and the working mode of the equipment is determined by the single-chip microcomputer.
