【正文】 根據(jù)功能將系統(tǒng)控制軟件分為兩大模塊： ① ADC0832 的驅(qū)動程序模塊，控制電壓信號的采集；② 1602LCD 的驅(qū)動程序 模塊，顯示土壤濕度。所示的仿真電路，再將由 Keil 軟件編譯并生成的系統(tǒng)驅(qū)動 程序 （“ *.hex 文 件 ”） 載 入 單 片 機(jī) ，并 將圖 2 中 的 虛擬直流電壓信號發(fā)生器設(shè)為 45mV。 其基本過程是先繪制好圖 3 所示的仿真電 路 后 ， 將 由 Keil 軟 件 編 譯 并 生 成 的 系 統(tǒng) 驅(qū) 動 軟 件（ hex 文件）載入 LPC2131。其字符顯示功能由內(nèi)部專用的驅(qū)動芯片 HD44780[4]準(zhǔn) ASCII 碼放入其內(nèi)部集成的數(shù)據(jù)顯示用存儲器（ DDRAM），內(nèi)部控制線 路就會自動將符傳送到顯示器上 。該模擬信號進(jìn)入 A/D 轉(zhuǎn)換芯片的 CH0 通道進(jìn)行轉(zhuǎn)換處理，所 得到數(shù)字信號再送入單片機(jī) AT89S51 進(jìn)行數(shù)據(jù)處理并由液晶顯示。 / / to be liquid crystal early beginning } 2)the production of clock When the clock points frequency device (after it can have to MHz in turn when the change in A/D clock) turn change when idle is empty, the hold after A state in ADCR is written to the START field immediately START 01 (conversion) or the selected edge appear in choice of signal sampling clock can immediately START. This feature can save power consumption. ADC conversion clock putation formula is as follows FADC=FPCK/（ CLKDIV+1） Type: Fpclk core slice。 ine Many studies, the various problems in agricultural production also widely adjustable Inquiry. Research found that gardening cultivation, greenhouse flowers, awning vegetables one Some valuable varieties of soil moisture, soil has a high requirement, humidity At the time, not only seriously affecting its normal growth, and even cause planting product death Wu, causing serious damage. Farmers Therefore, engaged in this kind of agricultural very need a low cost, small volume and detection reliable soil .Soil humidity detector for water supply, provides the basis. In order to solve the above asked .Our problem, I unit bined with actual conditions of agricultural production, and the related units designed Home of high precision, to design the low cost of miniature soil moisture detection instrument. Along with the social life progress, people39。s relative humidity 0% ~ 100% RH, its corresponding Output is 0 ~ 100mV [1]. According to the integrated amp with phase ratio amplification gain: Kf=R1+ Rf =1+ 47 =48 Then the output amplification V0 = 48 analog signal voltage, so output analog, Vi, electric pressure fan letter surrounded is 0 ~ . This mode, turn into A/D CH0 slice of replace core general way into line changeover place, have cut to several words AT89S51 singlechip letter Numbers again into data processing and the LCD. A/D conversion chip choice and controlling principle This article chooses A/D conversion chips for ADC0832, this chip is 8 Pin double row straight insert dual channel A/D converter, can separately for both road simulation No real now believe d/a change, can use in the ocl lose into mode and bad points to lose Under the way of DI server channel selected choose, several according to adopt sets and Data transfer [2]. The work of ADC0832 do sequence as shown in figure 3. Root according to our web site, when covariance .ADC0832 did not work, must the piece selected in the high level, the CS When chip disabled. When should undertake A/D conversion shall be piece selected end CS offsets In low level and maintains to convert over. Chip began to work, still need to make Monolithic machine to core chips, when the clock CLK lose faith in the clock pulse blunt when lose, In the first clock pulse before the sinking DI end must be high electric flat, tables And start signal. In the first 2, 3 pulse sinking DI end before should be lost Into two data used to select channels function. Channels are as follows: (1) the controlled conditions In accordance with The Times when DI