Design Of Portable Oscilloscop For Autocar Based On C8051F120

The naissance of automobile oscilloscope provide a powerful tool to men who mainten automobile , whice make them easily and fastly find failures of the automobile electronics equipments and fire-system. Currently, the foreign companies predominate the local market of automobile oscilloscope. The automobile oscillograph is hindered to apply wildly in the process of repairing and testing autocar by high price, whice badly baffle the development of our counter's industry of automobile maintenance. So, it is importent to develop and design automobile oscilloscope.We want to design a portable automobile oscilloscope which is used very conveniently in this paper , with light, using LCD, low-price. The Single-chip microcomputer C8051F120 controls the whole system, and at the same time it functions data processing. The CPLD EPM7256S works as the system's peripheral controller SRAM and A/D clock. By using LCD, it provides the friendly interface for user's convenient operation, and makes the system miniaurization and portable.The finished tasks of this project are as follows:(1) On the basis of the analysis of DSO's fundamental principle, the design of a kind of portable automobile oscilloscope system was discussed based on MCU and CPLD.(2) Designing four-channel data gather circuit based on ic chip. Designing sub-frequency,peak-value-catching and other logic control circuit based on complex programmable logic device. Designing system-spring,engine rotate speed measure circuit,and so on.(3) Designing hardware interface circuit between MCU and SRAM,LCD display-module,key-board,RS232. By debugging the circuit, achieveing our objective by and large.(4) On the basis of hardware circuit,we develop system software,wave-displaying and so on, based on modularizing-programme-design idea. And we use JTAG to debug the software on system circuit.By testing the system on ShenLongFuKang engine teaching platform,the validity of the system hardware design and the rationality of the system software design are proved.