Development And Application Of U Disk Read-writer Based On FPGA

Nowadays, the inner chips of portable instruments applied to agriculture and forest datacollection are small, so people always expand hardware to store data. However, expandinghardware reduces versatility of hardware, not conductive to power-fail protection. Based onanalyzing kinds of U disks present in home and abroad electronic design supermarket, thispaper combines FPGA and CH376chips to research a kind of portable instrument applied tostorage of high capacity data of outside agriculture and forest. And, deeply, make it asperipheral part of low-power collection instrument.The done U disk reader-writer makes FPGA as its core controller, consists of serial portmodule, USB interface module, A/D collection module, program storage module and othermodules. Respectively, serial port part receives data of the serial port. USB interface dealswith the received data to U disk by controlling U disk reader-writer CH376. Then, A/Dcollection part can convert analog to digital and collect digital signal by controlling A/D chipTLC549. Program storage part makes up of SDRAM and flash for storing start code andloading program. And, among other modules, JTAG makes online debug and load run cometrue, electric power module supplies power of the whole system. Based on the platform ofQuartus Ⅱ and Nios Ⅱ EDS, by integrating all parts, the done instrument can write and readserial port data, and has function of A/D conversion. Results of this paper are as follows.(1) Research and analyzes development status of U disk reader-writer in home andabroad, confirm the development plan and thought of this paper’s instrument.(2) Design serial communication controlling module, based on deep research ofasynchronous communication data frame format and serial receive/send time series.Simulation test proves its basic functions are normal. At last, by embedding the designedhardware controller interface into the inside of FPGA, the done instrument can control serialchip MAX3232.(3) Programming initial function, sending command function, read-write data functionand time lag function etc, with CH376chip data sheet as reference. Complete the programdesign of the whole USB interface part by deeply understanding API function of Nios Ⅱ.(4) Analyzes the controlling time series of A/D chip TLC549and Avalon-MM slaveinterface. Write Verilog hardware language program with three-state machine, complete designation of hardware controlling interface which has function of A/D conversion. Moreover, interface controller components which can convert analog and digital have been madesuccessfully.(5) By integrating all design parts and adding IP cores which are needed when systemruns, this paper completes the building and being of the whole hardware system. Besides,several time series restricts makes the time series of hardware system convergence and supplyhelp for software development.(6)Under the environment of Nios Ⅱ EDS, based on hardware system, this papercompletes writing, debugging and running function of every part’s software program.Having finished a circuit board production. Through experimental debugging, we successes todevelop a portable instrument that can be used to store a large number of agroforestry data under the conditions of a field no power supply.