这是基于PIC18F4550开发的USB的演示固件 ，使用MPLAB+C18开发环境，配合Microchip的MCHPFSUSB开发板使用。-This is based on the PIC18F4550 development demonstration USB firmware, use the MPLAB+ C18 development environment, coupled with Microchip' s development boards MCHPFSUSB use.