【文章內(nèi)容簡介】 ument, the domestic electric appliances, the numericallycontrolled machine tool, the industrial control and so on the electromechanical device and the product uses the monolithic integrated circuit unexpectedly. In the present case, monolithic integrated circuit39。s development momentum still does not reduce, each kind of model and a function stronger monolithic integrated circuit and the super connection chip appear unceasingly, is further constitutes the multiputer system and the distribution work to the top level development39。s important symbol. In the world the monolithic integrated circuit chip39。s output by every year 27% speed increase, to had reached 3,000,000,000 pieces at the beginning of the century, but our country39。s year demand has also surpassed hundred million piece of quantities, this indicated that the monolithic integrated circuit has the broad application prospect. This curriculum mainly 5 aims at the present our country early time application quite widespread “MCS51” the monolithic integrated circuit to carry on system39。s explanation and the analysis. In order to use and develop each kind of integration of machinery equipment and the measuring appliance establishment foundation. On the rotational speed table design has many available, but mostly by mechanical or simulated digital circuits to achieve. There are large in size, precision low, not visual, electronics large, less functional and sampling time, it is difficult to detect instantaneous rotational speed. As the Micro Controller Unit with both small and control functions such strong characteristics, so it widely in control applications. We want multifunctional rotational speed control system is designed to the Micro Controller Unit as the core to achieve intelligent meters. It is more functional, small electronics, and visual accuracy, showing time, speed warning systems, printing, such as instant rotational speed advantage. The article explained the photoelectric sensors such rotational speed table operating principles, structure and rotational speed switching circuit design. The design is a decoder MC14499, which is integrated high degree LED Motorola panies that drive, a dynamic scanning driven four LED digital display control. It sets Suocun, decoding, driving, scanning, the clock on integration. Has given take AT89C2051 as the core, using monolithic integrated circuit39。s operation and the control function, and uses the serial port liquid crystal display module real time display to measure the speed and the course speed odometer design proposal. Because this plan has used the serial port liquid crystal display module and EEPROM, as well as highly effective fast algorithm, thus may in saves the system resources and in the reduced program design foundation guarantees the measuring accuracy and system timeliness. This speed odometer by the signal pretreatment electric circuit, AT89C2051 monolithic integrated circuit, the serial port liquid crystal display electric circuit, the serial port data storage electric circuit and the system software is posed. And the signal pretreatment electric circuit contains the signal to enlarge, the profile transformation and the wave shaping. System hardware diagram as shown in Figure 1. In the signal 6 pretreatment electric circuit39。s amplifier uses to the testing signal carries on the enlargement, reduces to the testing signal scope request。 The profile transformation and the wave shaping electric circuit uses for signal conversion Cheng Ke who and the monolithic integrated circuit connection TTL signal will enlarge。 May enable the INT0 pin through monolithic integrated circuit39。s establishment to carry on the control to the internal timer T0 work, like this can the precise surveying leave adds to the INT0 pin the pulse width (. to determine signal impulse cycle)。 The speed display part uses the serial port liquid crystal display module, the obtained data uses the I2C main line and saves through E2PROM, thus saved has needed monolithic integrated circuit39。s mouth line and the periphery ponent, simultaneously also simplified the demonstration part software programming. the system software including the monolithic integrated circuit and the liquid crystal module39。s initialization module, the liquid crystal module writes the data/order submodule, the cyclical survey module, the speed course put