【正文】 h 允許程序存儲(chǔ)器在系統(tǒng)可編程，亦適于常規(guī)編程器。 綜合以上方案最后確立了各個(gè)模塊所使用的方案為 表 21 模塊所使用的方案表 中心控制模塊 STC89C52 被測(cè)電路模塊 充放電電路 顯示模塊 1602 液晶顯示器 各個(gè)模塊的硬件電路設(shè)計(jì) 中央控制模塊設(shè)計(jì) 1. STC89C52 單片機(jī)概述 STC89C52 是一種帶 8K 字節(jié)閃爍可編程可檫除只讀存儲(chǔ)器（ FPEROMFlash Programable and Erasable Read Only Memory ）的低電壓，高性能 COMOS8 的微 7 處理器，俗稱單片機(jī)。 被測(cè)電路模塊 方案一：利用 555 定時(shí)器組建定時(shí)模塊 555， 555定時(shí)器具有成本低， 性能可靠 等優(yōu)勢(shì)，雖然能夠做到精確定時(shí)但要進(jìn)行量程換擋，測(cè)量不夠直觀方便。但是利用模擬電路，硬件設(shè)計(jì)太過復(fù)雜，故不采取。 圖 21 系統(tǒng)組成框圖 中心控制模塊 方案一： 采用 CPLD 或 FPGA 實(shí)現(xiàn)應(yīng)用 ,目前廣泛應(yīng)用的 Verilog HDL 硬件電路描述語言，實(shí)現(xiàn) 電容測(cè)量測(cè)試儀 的設(shè)計(jì)，利用 MAXPLUSII 集成開發(fā)環(huán)境仿真、綜合，并下載到 CPLD 或 FPGA 可編程邏輯器件中，完成系統(tǒng)的控制作用。通過 單片機(jī)定時(shí)器 0 和定時(shí)器 1 和外部中斷 0 實(shí)現(xiàn)電容的測(cè)量 。 （ 3）其他創(chuàng)新功能 電容測(cè)量?jī)x設(shè)計(jì)的意義 本課題 選用 STC89C52 單片機(jī)來設(shè)計(jì) 電容測(cè)量?jī)x。 在本設(shè)計(jì)中 本課題 選用 STC89C52 單片機(jī)來設(shè)計(jì) 電容測(cè)量?jī)x ， 電容測(cè)量?jī)x 程序由 用 C 語言編寫 ， 由主程序、 計(jì)數(shù) 定時(shí)中斷服務(wù)子程序等模塊組成 ， 顯示是LCD1602 液晶顯示屏， 此設(shè)計(jì)中用了繼電器控制電容充放電， 測(cè)試原理見圖 ,電源經(jīng)電阻 R 給被測(cè)電容 充電， 被測(cè)電容 兩端原電壓隨充電時(shí)間的增加而上升。在電容測(cè)量?jī)x設(shè)計(jì)的定時(shí)計(jì)數(shù)系統(tǒng)中將得到更好的應(yīng)用 . 通常 情況下，電路參數(shù)的數(shù)字化測(cè)量是把被測(cè)參數(shù)傳換成直流電壓或頻率后進(jìn)行測(cè)量。 【 關(guān)鍵詞 】 STC89C52 單片機(jī) 繼電器 LM393 The capacitance meter Design and Implementation based on microcontroller 【 Abstract】 With the continuous development of science and technology, the continuous progress of human development in the field of electronic technology can be described by leaps and bounds, capacitor, however, has been widely used in electronic circuits, its size has an important role on the performance of the circuit. Therefore, the measurement of the capacitance in the daytoday use is inevitable. This design uses STC89C52 MCU and relay control capacitor charging and discharging the capacitor circuit of the main circuit measurement, capacitance measurement RC charge and discharge the basic realization of the principle. More kind of instrument for measuring capacitance ponents, the method is also different, but it has its advantages and disadvantages. The ships measuring method of putational plexity are present, is not easy to achieve automatic measurement. Here is convert the capacitive element parameters C charging time, time relay timing, SCM timer to calculate the charging time, when the capacitor is charged to the preset voltage LM393 inverted output low. LM393 output end to STC89C52 MCU INT0 mouth, external interrupt generated when the low singlechip, singlechip count and then puting the calculated C, and finally through the the LCD1602 display shows the measured capacitance value. In software design, the design uses the C language to write the program. 【 Key words 】 STC89C52 microcontroller relay LM393 2 目 錄 1 緒論 ......................................................................................................................................... 4 概述 ............................................................................................................................... 4 系統(tǒng)的性能要求及特點(diǎn) ............................................................................................... 4 電容測(cè)量?jī)x 設(shè)計(jì)的意義 ............................................................................................... 4 2 系統(tǒng)分析及硬件設(shè)計(jì) ............................................................................................................. 4 系統(tǒng)設(shè)計(jì)思路與方案比較論證 ................................................................................... 5 系統(tǒng)設(shè)計(jì)思路 ..................................................................................................... 5 系統(tǒng)設(shè)計(jì)原理 ..................................................................................................... 5 方案論證與確立 ................................................................................................. 5 各個(gè)模塊的硬件電路設(shè)計(jì) ........................................................................................... 6 中央控制模塊設(shè)計(jì) ............................................................................................. 6 顯示模塊設(shè)計(jì) ..................................................................................................... 7 被測(cè)電路 模塊設(shè)計(jì) ............................................................................................. 9 3 軟件設(shè)計(jì) .................................................................................................................................... 10 軟件設(shè)計(jì)功能 .......................................................................................................