【正文】 畢 業(yè) 設 計 [論 文 ]題目： 多功能電子秤 多功能電子秤11 摘 要該設計以 51 系列單片機 STC89C52 為控制核心，實現(xiàn)電子秤的基本控制功能。在設計系統(tǒng)時，為了更好地采用模塊化設計法，分步的設計各個單元功能模塊，系統(tǒng)的硬件部分可以分為最小系統(tǒng)、數(shù)據(jù)采集、人機交互界面和系統(tǒng)電源四大部分。最小系統(tǒng)部分主要包括 STC89C52 和擴展的外部數(shù)據(jù)存儲器；數(shù)據(jù)采集部分由壓力傳感器、信號的前級處理和 A/D 轉(zhuǎn)換部分組成；人機交互界面為鍵盤輸入和點陣式液晶顯示，主要使用 128X64 點陣液晶顯示器，可以方便的輸入數(shù)據(jù)和直觀的顯示中文。系統(tǒng)電源用一根 USB 線作為電源線,直接連接電腦的 USB 口,簡單了電源設計。軟件部分應用單片機 C 語言進行編程，實現(xiàn)了該設計的全部控制功能。該電子秤可以實現(xiàn)基本的稱重功能（稱重范圍為0～，重量誤差不大于177。）,并發(fā)揮部分的顯示購物清單的功能，可以設定十種商品的單價， 還具有超量程的報警功能。整個系統(tǒng)結(jié)構(gòu)簡單，使用方便，功能齊全，精度高，具有一定的開發(fā)價值。 關鍵詞：單片機；稱重傳感器；采樣電路；矩陣鍵盤；A/D 轉(zhuǎn)換器；液晶顯示 多功能電子秤2ABSTRACTThe design of 51 series microcontroller STC89C52 as the control center for electronic scale of the basic control functions. In designing the system, in order to better modular design, the design of each unit step function modules, the system can be divided into minimum system hardware, data acquisition, manmachine interface and system power four parts. STC89C52 minimum system and expand some of the major, including the external data memory。 data acquisition in part by the pressure sensor, signal processing and the first class A / D conversion part。 manmachine interface for the keyboard and dot matrix liquid crystal display, the main use of 128X64 dotmatrix liquid crystal display, you can easily input data and visual display of Chinese. System power supply with a USB cable as power lines, directly connected to the puter39。s USB port, simple power supply design. Software part of the application microcontroller C programming language, designed to achieve all the control functions. The electronic weighing scales can realize the basic functions (weighing range is 0 ~ , the weight of error of less than 177。 ), and played portions of the shopping list of features, you can set the unit price of ten modities, but also superrange alarm. The whole system is simple, easy to use, fully functional, high precision, has a development value. Key words: microcontroller。 load cell。 sampling circuit。 matrix keyboard。 A / D converter。 LCD 多功能電子秤3目 錄1 摘 要 ...............................................................................................................................................1目 錄 .......................................................................................................................................................32 前 言 .................................................................................................................................................4 選題背景 ...................................................................................................................................4 電子秤簡介 ...............................................................................................................................5 電子秤的定義 ..................................................................................................................5 電子秤的分類 ..................................................................................................................5 電子秤的計量性能 ..........................................................................................................6 電子秤的特點 ..................................................................................................................6 電子秤的發(fā)展方向 ..........................................................................................................73 系統(tǒng)開發(fā)軟硬件概述 .......................................................................................................................7 單片機的選型 ...........................................................................................................................7 PROTEUS 仿真軟件簡介 ...........................................................................................................9 KEIL 編譯及調(diào)試軟件簡介 ....................................................................................................104 系統(tǒng)構(gòu)成及工作原理 .....................................................................................................................12 系統(tǒng)總體設計方案比較與論證 .............................................................................................12 本系統(tǒng)的設計思路 .................................................................................................................13 本系統(tǒng)的功能 ................................................................................................................14 系統(tǒng)設計方案 ................................................................................................................145 硬件電路設計 .................................................................................................................................16 單片機電路模塊框圖 ............