The Interface Module Design Of Integrated Experimental Platform Based On ARM Linux System

This subject comes from one of teaching reform projects for master degreecandidate in ‘985’ project, and this subject is mainly about interface conversion projectof integrated experimental platform which is researched and developed by collegeindependently in order to popularize practical teaching. The experimental platformincludes52types of modules and supporting emulator. The interface conversionprojects includes the design and implementation of hardware and software of USB、GPIB、LAN interface conversion card.Through the analysis of the demand of the integrated experimental platform, inorder to make convenience for computer data correspondence, adopting themultifunctional interface module is a good choice. The interface module is based on theembedded Linux system and the ARM9processor, the content of project includes:Fist, the selection of ARM chip and interface module chip, adopting the ARM9microprocessor AT91RM9200、 GPIB extension chip NAT9914and the Ethernetphysical layer chip DM9161EP;Second, schematic drawing, using the MENTOR to design the interface boardschematic and draw the PCB。Complete the conversion of the USB interface to the LANinterface and the USB interface to the GPIB interface respectively. Because of theincompatible timing sequence between the ARM and NAT9914, adopting the I/O portsimulation Bus timing sequence scheme can solve this problem. Finish hardwaredebugging in order to ensure that the Linux system can perform normally under theinterface board;Third, the structure of the module with embedding Linux system includes ofestablishing a cross-compiler environment、 transplantation of the Boot Loaderprogram、transplantation of Linux system kernel and initialization process;Fourth, the USB driver optimization and design of GPIB device driver.Fist of alloptimize the corresponding driver which is provided by the USB interface chipmanufacturers under Linux system in order to improve the data transmission rate, in linewith the actual demand of experiment platform; Then, under the circumstance of no GPIB driver is provided by Linux device drivers, write the driver of the GPIB chipNAT9914to realize the GPIB interface based on ARM and Linux.At the present time the subject is done, and the designed interface conversionmodule displays stable performance by test，the capacity of data transmission is fine andsatisfies the requirement of experiment platform work，the module has entered the stageof bulk production already.