Design And Realization Of USB HID Device Based On C8051F MCU Family

With the development of computer technology,USB has become a common standard for computer and external equipment connection.The biggest feature of USB is the high speed,easy to use,easy to expand,supporting hot-swappable and there are large number of operating systems have provided support for it.With the improving of the USB rate and the increasing of the USB stability,its use will be more and more widely.Not only in the field of non-PC applications,but also will be the trend of embedded areas.The USB interface technology will provide a more convenient solution for data transfer between PC hosts and peripherals.This paper have analyzed the USB protocol,studied the system topology of USB bus and expounded the functions of USB host and USB device.This paper have also introduced the data transmission type and USB communication protocol of USB and have analyzed the device architecture,which have introduced the device status,descriptor,standard request and HID class.The USB protocol layer is the core of the entire USB device and handles most of the content specified in the USB protocol.This paper has analyzed the transceiver and serial interface engine in the USB system to achieve the function according to the USB2.0 protocol layer architecture.In addition,this paper has studied the use of UTMI protocol and USB microcontrollers chip.After detailed analysis of the USB protocol architecture,the C8051 F series microcontrollers with on-chip integrated USB controller were selected to design a USB HID device system,which has realized the data communication between the master and the front panel.Before the design,This paper has discussed the development background of the intelligent instrument and the classification of the computer outside bus before the design.The paper compares USB bus with the GPIB bus and RS232 bus,which reflects the big advantage of the USB bus.USB system software design includes the device firmware program and the host computer software.Device firmware program using the background design concept,which can be divided into two modules: USB common module and USB device protocol module.Common module achieves the initialization of the device,key scans and sends the report;protocol module completes the interrupt handling,the send and reply between host and HID device command.The host computer software includes device drivers and client applications.This article generates a system driver INF file,which suit to Windows system.After the installing of the device driver,the host can identify the device correctly.The client application is implemented using the host computer dynamic link library in the USBXpress development kit.USB system has successfully realized the USB data communication by the use of BUS HOUND software to capture bus packets after the system is completed.