【正文】 a portable, easy operating, high precision scales, clearly meet the needs of the people. In this paper, Sonix SN8P1937 MCU core, based on AutoRun feature, it works when weight tested reaches the minimum of the weighing scales,unlike the previous of weighing scales use foot pedal to begin counting. The MCU integrates a 16bit AD conversion, programmable gain amplifiers, LCD driver rich onchip resources and so on. The system only weighing when in normal mode, open the hardware resources, the other time working in the green mode, green mode only cost a few microamps of current,so this kind of weighing scales is very power savings and have a good practical and environmental protection. The design is divided into two parts, hardware design and software design. The part of hardware design is divided into: LCD display part, the pressure signal acquisition and change, EEPROM, low voltage detection module and some buttons. As the pressure sensor output signal is nonlinear, so if the linear approach will cause error. The method used piecewise linear to plete the part of AD conversion part and the design of amplifier circuit. At first,software part plete the bottom driver of each module, and then plete the design of application layer, eventually the system to achieve the desired results. KEYWORDS:Weighing Scale,SN8P1973,AutoRun Function, Pressure Sensor III 目 錄 摘 要 ........................................................................................................................................... I Abstract.......................................................................................................................................II 1 緒論 ........................................................................................................................................ 1 引言 .............................................................................................................................. 1 稱(chēng)重技術(shù) 和衡器的現(xiàn)狀和發(fā)展趨勢(shì) .......................................................................... 1 體重秤的研究現(xiàn)狀和發(fā)展趨勢(shì) .................................................................................. 2 課題提出的背景和意義 .............................................................................................. 3 課題的主要工作及論 文結(jié)構(gòu)安排 .............................................................................. 3 2 體重秤 功能 與操作方法 ........................................................................................................ 5 體重秤的 功能 .............................................................................................................. 5 稱(chēng)重 .................................................................................................................... 5 零點(diǎn)校正 ............................................................................................................ 5 分段校正 ............................................................................................................ 5 增益設(shè)置 ............................................................................................................ 5 AD 采樣速率設(shè)置 .............................................................................................. 6 AD 參考電壓設(shè)置 .............................................................................................. 6 LCD 參數(shù)設(shè)置 .................................................................................................... 6 體重秤的操作 .............................................................................................................. 6 本章小結(jié) ...................................................................................................................... 6 3 系統(tǒng)總體設(shè)計(jì) ........................................................................................................................ 7 系統(tǒng)方案選擇 .............................................................................................................. 7 單片機(jī)選擇 .................................................................................................................. 8 傳感器選擇 ................................................................................................................ 12 顯示器件選擇 ............................................................................................................ 13 本章小結(jié) .................................................................................................................... 14 4 系統(tǒng)硬件設(shè)計(jì) ...................................................................................................................... 15 單片機(jī)外圍硬件電路設(shè)計(jì) ........................................................................................ 15 傳感器電路 ................................................................................................................ 16 液晶驅(qū)動(dòng)電路設(shè)計(jì) .................................................................................................... 17 鍵盤(pán)電路設(shè)計(jì) ............................................................................................................ 18 EEPROM 外 圍電路設(shè)計(jì) ............................................................................................ 19 通道轉(zhuǎn)換和自動(dòng)增益電路 ........................................................................................ 20 IV 電池低電壓檢測(cè)電路 ................................................................................................ 21 AD 外圍電路設(shè)計(jì) ....................................................................................................... 23 系統(tǒng)總體電路圖 ........................................................................................................ 25 本章小結(jié) ................................................................................................................... 25 5 系統(tǒng)軟件設(shè)計(jì) ...................................................................................................................... 26 系統(tǒng)軟件總體架構(gòu)設(shè)計(jì) ..........................