【正文】 在實(shí)踐的過(guò)程中鍛煉了自己的動(dòng)手能力和團(tuán)隊(duì)協(xié)作能力，為自己以后能更快的投入工作提供了一定的經(jīng)驗(yàn)！ 英語(yǔ)翻譯Microcontroller reset is to make the CPU and other system features are in a defined initial state, and from this state to work, reset PC = 0000H, the microcontroller from the first a unit to take mand. Whether it is connected to the microcontroller when the power is just the beginning, or after power failure or failure to be reset. MCU reset conditions are: the RST pin must be coupled with continued two machine cycles (ie 24 oscillations) is high. Clock frequency in this article 12MHz, each machine cycle is 1μs, then the only 2μs time high above, appears in the RST pin high after the implementation of the second machine cycle reset.Reset circuit constituted by the capacitor series resistance, bined with the map, the capacitor voltage can not be mutatedin nature, can know when the system is a power, RST will be a foot high, and that the duration of this high by the circuit The RC values ??to decide. Appropriate bination of RC values ??can ensure a reliable reset. The circuit in addition to a poweron reset functions, to reset, just press the RESET button, then power through resistance, voltage, reset in the RESET high end.Clock circuit main task is to provide a working frequency. Internal microcontroller used to form a highgain inverting amplifier oscillator, the amplifier input and output are XTAL1 and XTAL2, XTAL1 and XTAL2 on the external clock source can constitute a clock circuit. Both internal and external clock generation mode. This design uses the internal clock generation means. Circuit connection shown in Figure , both ends of the jumper XTAL1 and XTAL2 crystal resonator (oscillator frequency 12MHZ), and internal selfexcited oscillator inverter constituted. The issue of pulse timing control directly into the onchip ponents. In addition, the capacitance of the frequency tuning role, as an external crystal oscillator, capacitor selection 20pF, practical application, and capacitor resonator near as possible to install in the SCM to reduce the parasitic capacitance, the oscillator stable and reliable work.Ultrasonic transmitting circuit includes ultrasonic generator circuit and the ultrasonic transmitter control circuit of two parts, ultrasound probes (also known as ultrasonic transducer) use CSB40T. 40KHz is the use of ultrasonic oscillation drive circuit 555 produce ultrasonic probe.555 constituted by the multivibrator timer (shown in Figure ). Power, the power by charging the capacitor and, when 1 / 3, the oscillator output = 1, the discharge end. When the charge to ≥ 2 / 3, the oscillator output flip to 0, then discharge tube turns on, the discharge end (DIS) grounded, capacitor C discharges through the ground, so that decline. Present down to ≤ 1 / 3, the oscillator output and turn into 1, discharge and cutoff time, so that the discharge end (DIS) is not grounded, power, and again by charging the capacitor, and also allows from 1 / 3 up to 2 / 3, flipflop flip took place, again and again to be a continuous change in the output of the oscillator pulse. Pulse width of ≈ , determined by the capacitor discharge time。s the fourth film as LM324 parator inverting potential, the circuit shown in Figure , there is a threshold voltage, the voltage parator inverting input voltage. Threshold voltage adjustment potentiometer available. When the time, = 0, is low: when the time, = , is high. When the LM324 ultrasonic echo signal is detected, it outputs low level signal, this time for LM324 input voltage is less than the threshold voltage, the LM324 to the output level signal, leading to end of data acquisition PC. On the contrary, the output signal to the PC for the low end of data acquisition. This part of the parator adjusted properly if there could be some problems, such as the output will be highfrequency output. This is because the parator is very sensitive to small changes in the signal causes the output values ??and the mutual transformation. Use of the positive feedback of the parator hysteresis to reduce sensitivity of the parator can reduce the interference. Because the amplified echo signal amplitude is large, so then by setting the appropriate threshold can be effectively stable signal. Use of adjustable potentiometer is a more convenient way. Needs the input of the parator reference voltage stability need to add capacitance stability. Reasonable adjustment potentiometer, select the parison reference voltage, allows more accurate and stable measurement.參考文獻(xiàn)《單片機(jī)應(yīng)用技術(shù)教程》………………………………………… 張洪潤(rùn) 藍(lán)清華主編清華大學(xué)出版社 1997年5月出版《單片機(jī)原理與控制技術(shù)》…………………………………………………陳麗芳主編東南大學(xué)出版社 2003年7月出版 《單片機(jī)應(yīng)用技術(shù)》…………………………………………………………劉守義主編 西安電子科技大學(xué)出版社 2002年8月出版《單片微機(jī)系統(tǒng)》……………………………………………………………蔣力培主編 機(jī)械工業(yè)出版社 2004年2月出版《超聲手冊(cè)》……………………………………………………………………馮諾主編南京大學(xué)出版社 2002年5月出版《超聲波測(cè)距儀在汽車(chē)安全系統(tǒng)中的應(yīng)用》………………………………肖質(zhì)紅主編萬(wàn)里學(xué)院學(xué)報(bào)出版 2007年5月出版．《超聲波測(cè)距系統(tǒng)的設(shè)計(jì)與實(shí)現(xiàn)電子技術(shù)應(yīng)用》…………………………徐國(guó)華主編l995年12月出版《基于超聲波測(cè)距系統(tǒng)的溫度補(bǔ)償田勝軍》…………………… 秦宣云 何永強(qiáng)主編2007年5