【導(dǎo)讀】計數(shù)器記錄汽車行駛的累計里程?，F(xiàn)代汽車正向高速化方向發(fā)展，隨著車速的提高，凡此種種，使得基于非接觸式轉(zhuǎn)速傳感器的電子式轉(zhuǎn)速里程表得以迅速發(fā)。是現(xiàn)在的液晶儀表盤，不可能再通過撥數(shù)碼輪調(diào)整里程表。司機又需要增加里程數(shù)時，這種跑表器使用中規(guī)模集成電路設(shè)計而成，體積。小巧，運行穩(wěn)定，適用于各種電子傳感器的汽車上使用。為了提高電路工作的可靠性，不但元件經(jīng)過精心篩選，而。據(jù)車型不同，速度有所不同，可以通過調(diào)整儀器上速度旋鈕改變速度。該顯示共分兩行顯示，第一行6位顯示累計里。為了保證累計里程單元的個位或小計單元。據(jù)移動到新單元以繼續(xù)計數(shù)。集成電路驅(qū)動十字線圈表頭，從而實現(xiàn)了車速的指示。經(jīng)實際使用證明，該里程表完全可以取代傳統(tǒng)的以軟軸驅(qū)動的車速里程表?？紤]到信號的衰減、干擾等影響，在信號送入單片機前。應(yīng)對其進行放大整形，然后再輸入到單片機進行測速。

　　

【正文】 nal 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. This design can realtime the speed display which measured, simultaneously can also accumulate demonstrates the total course number. This speed odometer can input the sensor to monolithic integrated circuit39。s signal impulse width (sensor transforms vehicle speed corresponding width signal impulse) realtime to survey, then calculates the speed and the course through the monolithic integrated circuit, again the obtained data storage to the serial port datacarrier storage, and will measure the speed by the serial port liquid crystal display module real time display. This design controls the demonstration speed or the course with two pressed keys. Considers the signal influences and so on weaken, disturbance, before the signal sends in the monolithic integrated circuit to deal with it to carry on the enlargement reshaping, then inputs again to the monolithic integrated circuit carries on measures fast. Monolithic integrated circuit determi nes input signal after the timer T0 control function the cycle, again using monolithic integrated circuit39。s arithmetic operation function the cycle transforms the speed, simultaneously each second carries on a course to accumulate, thus calculates the total course. Finally will obtain the speed, the course value save in E2PROM, and demonstrates the speed or the course according to two pressed key39。s choice situations. For the convenience putation must demonstrate data value Duan Ma, may transform again it the pression the BCD code, then in the data value which is going to demonstrate through the table lookup each pression BCD code transforms 8 sections of codes to deliver the demonstration buffer, finally passes through the serial port to deliver to the liquid crystal display module demonstrated measured speed or course. When design, should the overall evaluation measure the fast precision and the system reaction time. This design with measuring impulse frequency putation speed, thus has high measures the fast precision. For guarantee system39。s timeliness, system39。s speed change module and the demonstration data transfer the BCD code module to use the fast algorithm. Moreover, but should also guarantee other submodule in programming time versatility and highly effective as far as possible. This design39。s speed and the course value use 8 demonstrations, and contains two decimal places. This article introduced one kind based on the monolithic integrated circuit AT89C2051 speed odometer39。s design method. Because in this plan has used the serial port section code liquid crystal display module EEPROM reservoir, thus has saved the hardware source, enhanced the system performancetoprice ratio. At the same time, is also beneficial in expands other functions in this electric circuit foundation using monolithic integrated circuit39。s resources.