【正文】 In order to guarantee the accumulation course unit the units place or subtotal unit decimal place reliable refurbishing, when these unit close limit use cycle, may adopt the form feed the means to cause these data to move to the new unit continues to count. The Hall sensor has many merits, their structure is reliable, the volume is small, the weight is light, the life is long, the easy installation, the power loss is small, the frequency 3 high (may reach 1MHZ), bears the vibration, does not fear the dust, the greasy dirt, the water vapor and the salt mist and so on pollution or the corrosion. The Hall linear unit39。s important branch, it has the volume to be young, price low, face control characteristic, is suitable in each industrial control, the instruments and meters installment, has the extremely widespread application in the human production and life each domain. In recent years, microputer39。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 6 the wave shaping. System hardware diagram as shown in Figure 1. In the signal pretreatment electric 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 determines input signal after the 7 timer T0 control function the cycle, again using 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 year demand has also surpassed hundred million piece of quantities, this indicated that the 5 monolithic integrated circuit has the broad application prospect. This