【正文】 II ABSTRACT Nowadays the number of vehicles on the road are increased year by year, so the car parking problem must be solved to obtain the very good, otherwise the consequence is unimaginable. When parking, if it39。 AT89C2051 是一種帶 2K字節(jié)閃存可編程可擦除只讀存儲(chǔ)器的單片機(jī)。本方案采用語(yǔ)音提示的方式，本文介紹了以AT89C51 單片機(jī)為核心的一種低成本、高精度、微型化，并有數(shù)字顯示和聲光報(bào)警功能的倒車(chē)?yán)走_(dá)系統(tǒng)。 泊車(chē)輔助系統(tǒng)是一種能夠?qū)崟r(shí)顯示車(chē)后障礙物狀況的汽車(chē)倒車(chē)輔助裝置，在現(xiàn)實(shí)生活中應(yīng)用十分廣泛。停車(chē)時(shí)如果光是靠駕駛員的經(jīng)驗(yàn)和技術(shù)是不夠的，所以智能泊車(chē)輔助系 統(tǒng)（倒車(chē)?yán)走_(dá)）也就因此而誕生。倒車(chē)?yán)走_(dá)的提示方式可分為液晶、語(yǔ)言和聲音三種；接收方式有無(wú)線傳輸和有線傳輸?shù)取? 本次設(shè)計(jì)選用的芯片為 AT89C2051， AT89C2051 是一種帶 4K 字節(jié) FLASH 存儲(chǔ)器（ FPEROM— Flash Programmable and Erasable Read Only Memory）的低電壓、高性能CMOS 8 位微處理器， 俗稱(chēng)單片機(jī)。由于將多功能 8位 CPU 和閃爍存儲(chǔ)器組合在單個(gè)芯片中， ATMEL 的 AT89C2051是一種高效微控制器， AT89C2051 是它的一種精簡(jiǎn)版本 AT89C2051 單片機(jī)為很多嵌入式控制系統(tǒng)提供了一種靈活性高且價(jià)廉的方案。 Reception mode such as wireless transmission and cable transmission. This scheme adopts the voice prompt manner, this paper introduces the AT89C51 singlechip microputer as the core of a low cost, high precision, miniaturization, and has the function of digital display and audible and visual alarm reversing radar system. Using AT89C51 single chip have voice capability, external three ultrasonic ranging module, posed of a sample of reversing radar systems, voice alarm ( m ~ m) within the scope of the obstacles. Second, SCM is a kind of high integration, fast puting speed, small volume, reliable operation, low price chip, so in control, data acquisition, mechanical and electrical integration, intelligent instruments, household electrical and work technology is widely used and so on various aspects, this design is mainly study the application of microcontroller in the parking auxiliary system. This design chooses the chip AT89C51, AT89C51 is a with 4 k byte FLASH Memory (FPEROM FLASH Programmable and Erasable Read Only Memory) of low voltage, high performance CMOS 8bit microprocessor, monly known as the single chip microputer. AT89C2051 is a zone 2 k byte flash programmable microcontroller can erase the read only memory (ROM). MCU can erase readonly memory can be erased repeatedly III 1000 times. The mining ATMEL highdensity nonvolatile memory device manufacture technology, and industry standard of MCS 51 JiaoXiang patible instruction set and output pipe. Due to the multifunction 8bit CPU and flash memory in single chip AT89C51 of ATMEL is an effective and micro controller, AT89C2051 is it a strippeddown version of AT89C51 as many embedded control system provides a high flexibility and low price. Keywords: Reversing radar, singlechip, ultrasonic sensor, controller and display IV 目 錄 摘 要 ........................................................ I ABSTRACT .................................................... II 目 錄 ....................................................... IV 前 言 ........................................................ 1 第 1 章 緒 論 ................................................. 2 選題的意義 .......................................................... 2 泊車(chē)輔助系統(tǒng)的應(yīng)用 與發(fā)展 ............................................ 2 泊車(chē)輔助系統(tǒng)的發(fā)展方向與趨勢(shì) ........................................ 3 系統(tǒng)工作原理 ........................................................ 4 第 2 章 泊車(chē)輔助系統(tǒng)的設(shè)計(jì)方案 ................................. 6 測(cè)距方式和提示方式比較 .............................................. 6 測(cè)距方式 ........................................................ 6 預(yù)警提示方式 .................................................... 8 方案確定 ............................................................ 8 測(cè)距探測(cè)器方案 .................................................. 9 超聲波發(fā)射方案 ................................................. 10 超聲波回波接收方案 ............................................. 10 溫度測(cè)量及補(bǔ)償方案 ............................................. 11 顯示及報(bào)警方案 ................................................. 11 第 3 章 系統(tǒng)硬件設(shè)計(jì) ......................................... 12 硬件框圖 ........................................................... 12 單片機(jī)最小系統(tǒng)設(shè)計(jì) ................................................. 12 超聲波發(fā)送電 路設(shè)計(jì) ................................................. 13 超聲波接收電路設(shè)計(jì) ................................................. 15 溫度測(cè)量電路設(shè)計(jì) ................................................... 17 報(bào)警電路設(shè)計(jì) ....................................................... 19 顯示電路設(shè)計(jì) ....................................................... 19 電源電路設(shè)計(jì) ....................................................... 21 V +5V 和 +12V 穩(wěn)壓電源 ............................................. 21 穩(wěn)壓電源電路 ................................................... 22 器件選型 ........................................................... 22 AT89C2051 單片機(jī) ................................................ 22 超聲波傳感器 ................................................... 23 第 4 章 系統(tǒng)軟件設(shè)計(jì)和仿真 ................................... 24 系統(tǒng)軟件結(jié)構(gòu) ....................................................... 24 軟件程序設(shè)計(jì) ....................................................... 24 主程序 ......................................................... 24 三通道選擇程序 ................................................. 26 三通道數(shù)值 比較程序 ............................................. 26 距離計(jì)算子程序 ................................................. 27 報(bào)警及顯示程序 ................................................. 31 外部中斷程序 ................................................... 32 系統(tǒng)仿真 ........................................................... 33 結(jié) 論 ....................................................... 36 參考文獻(xiàn) .................................................... 37 致 謝 ....................................................... 38 附 錄 總電路圖 .............................................. 39 1 前 言 隨著社會(huì)的發(fā)展，汽車(chē)數(shù)量不斷增加，人們便對(duì)汽車(chē)操作的便捷性愈加挑剔。超聲波汽車(chē)倒車(chē) 雷達(dá) 是一種汽車(chē)泊車(chē)安全輔助裝置，能以聲音或者更為直觀的顯示告知駕駛員周?chē)系K物的情況，