單片機(jī)畢業(yè)設(shè)計(jì)外文翻譯---基于 at89s51 單片機(jī)的微型土壤濕度檢測(cè)儀設(shè)計(jì)

1、<p><b>　　畢 業(yè) 設(shè) 計(jì)</b></p><p><b>　?。ㄍ馕姆g材料）</b></p><p>　　2011年 6 月 </p><p>　　The design Based on AT89S51 miniature soil humidity detector design</p

2、><p>　　Abstract: facilitate master soil moisture conditions, design the miniature soil humidity detector. Its hardware system includes signal amplifier circuit, A/D circuit, SCM, micro LCD display and alarm cir

3、cuit, etc.; Software system includes A/D conversion driver, LCD driver two modules. Proteus software platform based on the design of the system is simulated, and the results show that the system hardware and software des

4、ign correct and reliable operation.</p><p>　　Keywords: soil humidity; Detector; SCM; A/D conversion; simulation</p><p>　　TP202 classification number: Chinese</p><p>　　Literature ide

5、ntification code: A</p><p>　　Section 1 Introduction</p><p>　　Agricultural production in the economic development of our country has important position, for farmers Industry production to provi

6、de timely and reliablly technical service has become the heavily meteorological department To response one. Along with the national governments at all levels of agricultural production increasingly heavier</p><

7、;p>　　Depende on the service, my unit also serve for agriculture, promote for increasing farmers' income</p><p>　　Many studies, the various problems in agricultural production also widely adjustable<

8、;/p><p>　　Inquiry. Research found that gardening cultivation, greenhouse flowers, awning vegetables one</p><p>　　Some valuable varieties of soil moisture, soil has a high requirement, humidity</

9、p><p>　　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 production.Farmers

10、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 combined with actual conditions of agric

11、ultural production, and the related units designed</p><p>　　Home of high precision, to design the low cost of miniature soil moisture detection instrument.</p><p>　　Along with the social life pr

12、ogress, people's quality of life is getting much more better, flowers has become a fashion. Flowers can not only enrich people's cultural life and is good for mental and bodily health ，but also can improve and pu

13、rify air, improve health. Water is necessary for flower’s growth ,it influences the growth of flowers greatly. Too much water or too little, will affect the normal growth and the kind of flower is verious, Different f

14、lowers need different amount of water. </p><p>　　Section 2 composition of the system </p><p>　　The whole system consists of SCM, circuit of DAQ, keyboard input and digital display circuit, outpu

15、t controlling circuit etc. circuit of CAQ is made of 4 SRH and adc , SRH makes flower’s soil humidity convert into analog voltage output, adc makes the output of analog voltage convert into digital quantity and send to m

16、icrocontroller. AT89S52 is adopted, the collectted value of soil humidity is compared with a preset limit soil moisture, and it makes corresponding judgement according to the compar</p><p>　　Miniature soil d

17、etector signal processing system including soil humidity sensor</p><p>　　Device, A/D acquisition circuit, SCM and micro LCD. Its work After cheng is: soil soil wet degrees preach sensor, will wet degrees let

18、ter sent to A/D adopt set electricity</p><p>　　Road, the A/D conversion, income data digital signal into SCM Processing, finally will processing results sent to micro LCD display.</p><p>　　Secti

19、on 3 the hardware design of system </p><p>　　3.1 the circuit’s working principle </p><p>　　The hard thing the original reason system graph as figure 2 shows. This article selects KSC -6V integra

20、ted relative humidity sensor, wait for after inserting the soil about 5s make sensor</p><p>　　Implement fully contact with the soil, signal by integrated amp LM324 Vin the same phase</p><p>　　In

21、put terminal. The sensor's relative humidity 0% ~ 100% RH, its corresponding</p><p>　　Output is 0 ~ 100mV [1]. According to the integrated amp with phase ratio amplification gain: Kf=R1+ Rf =1+ 47 =48<

22、;/p><p>　　Then the output amplification V0 = 48 analog signal voltage, so output analog, Vi, electric pressure fan letter surrounded is 0 ~ 4.8v. This mode, turn into A/D CH0 slice of replace core general way

23、into line changeover place, have cut to several words AT89S51 single-chip letter Numbers again into data processing and the LCD.</p><p>　　3.2 A/D conversion chip choice and controlling principle</p>&

24、lt;p>　　This article chooses A/D conversion chips for ADC0832, this chip is 8</p><p>　　Pin double row straight insert dual channel A/D converter, can separately for both road simulation No real now believe

25、 d/a change, can use in the ocl lose into mode and bad points to lose</p><p>　　Under the way of DI server channel selected choose, several according to adopt sets and Data transfer [2].</p><p>　

26、　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</p><p>　　When chip disabled. Wh

27、en should undertake A/D conversion shall be piece selected end CS offsets</p><p>　　In low level and maintains to convert over. Chip began to work, still need to make</p><p>　　Monolithic machine

28、to core chips, when the clock CLK lose faith in the clock pulse blunt when lose,</p><p>　　In the first clock pulse before the sinking DI end must be high electric flat, tables</p><p>　　And start

29、 signal. In the first 2, 3 pulse sinking DI end before should be lost</p><p>　　Into two data used to select channels function. Channels are as follows:</p><p>　　(1) the controlled conditions<

30、/p><p>　　In accordance with The Times when DI lost with 1, 0, the only way to do CH0 tong general turned into single wordChange; </p><p>　　(2) when DI ordinal input 1, 1, only for single CH1 channe

31、l onTao transformation;</p><p>　　(3) when DI ordinal 0, 0, will CH0 as is, will CH0 input 0 as its negative input IN CH1 -, as are the input IN +</p><p>　　3.3 microcontroller’s choice</p>

32、<p>　　MCU is the control of core, compared with the others ,we chose AT89S51 single-chip microcomputer. The advantages of this type of single-chip microcomputer is [3] : </p><p>　　(1) The single-chip

33、microcomputer and the 8051 series microcontroller is fully compatible, make it use easily, and into the ten points Cheap; </p><p>　　(2) Internal memory can be repeated CaXie by the EEPRROM, be helpful for re

34、peatting modify the program;</p><p>　　(3) has the low consumption working methods and to be achieved Off electrical automatic protection; </p><p>　　(4) has strong anti-jamming, greatly improving

35、 the worthRoyal external electromagnetic interference ability, so it is especially suitable for relatively tough in conditions Under the poor conditions of the job.</p><p>　　3.4 The use of LCD</p>&l

36、t;p>　　Using micro LCD display device, 1602LCD, its performance point is: working voltage only 4.5 ~ 5.5 V; Very low power consumption (work current</p><p>　　Only 2.0 mA); And reliable work; Small volume (

37、can show 16 x 2 words</p><p>　　Operators). Its characters are displayed by internal special displacement function of HD44780 dynamic core slice [4]</p><p>　　Quasi ASCII put into their number wit

38、hin department set into reservoir with deposit according to show and editor (DDRAM), inside the ministry accused of line of road will move will word from sheba operators preach send to show, Implement. Monolithic machin

39、e and the number of 1602LCD between general P0 into change had to enter line, resistance for P0 mouth R9 R2 ~ the pull-up resistors</p><p>　　Section 4 The software design of the control of system</p>

40、<p>　　This recorder controlling software design adopts modular thought.</p><p>　　According to the function,w emake the controlling system software devide into two big modules: </p><p>　　(1

41、) ADC0832 driver module, to control the collection of voltage signal;</p><p>　　(2) 1602LCD driver module, show soil humidity. This system driver using C</p><p>　　Language design, its main progra

42、m is as follows</p><p>　　Main (void)</p><p><b>　　{</b></p><p>　　unsigned int AD_val;</p><p>　　Convert the value after the</p><p>　　unsigned int

43、 Int, Dec;</p><p>　　The converted the integer part and the decimal part</p><p>　　/ / storage save A/D</p><p>　　/ / points don't store in existence</p><p><b>　

44、　change</b></p><p>　　LcdInitiate ();</p><p>　　/ / to be liquid crystal early beginning</p><p><b>　　}</b></p><p>　　2)the production of clock</p>

45、<p>　　When the clock points frequency device (after it can have to 4.5 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 immediat

46、ely 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 computation formula is as follows</p>&

47、lt;p>　　FADC=FPCK/（CLKDIV+1）</p><p>　　Type: Fpclk - core slice; when the clock set After CLKDIV - points of ADC conversion clock frequency.</p><p>　　3) interrupted.</p><p>　　When

48、DONE bits is 1, A/D conversion module to vector interrupt controller (VIC) issued an interrupt request in the VICIntEnable VIC, if Bit8 (A/D conversion interrupts enabled bits) make can, then can produce the interruption

49、. Read ADDR will reset DONE bits. This paper mainly A/D acquisition C language driver section design is as follows:</p><p>　　/***********************************</p><p>　　Function: A/D acquisiti

50、on</p><p>　　Entrance parameters: CH_i</p><p>　　/***********************************</p><p>　　void AD_Change(unsigned char CH_i)</p><p><b>　　{</b></p>

51、<p>　　ADC0R = (1 < < CH_i) | / / choose channels I carry A/D acquisition ((Fpclk / 1,000, 000-1) < < 8 | / / set convert clock</p><p>　　(0 < < 16)</p><p>　　(0 < < 1

52、9)</p><p>　　| / / BURST = 0, software control conversion operations</p><p>　　| / / normal A/D acquisition modes</p><p>　　(0 < < 27);| / / decrease along the startup conversion

53、</p><p>　　AD0DR; DO = / / read take ADC and fruit, and clear except</p><p>　　DONE mark bits</p><p><b>　　while (1)</b></p><p><b>　　.</b></p>

54、;<p><b>　　.</b></p><p><b>　　}</b></p><p>　　Section5 temperature measuring system of Proteus software simulation</p><p>　　To ensure system on the hardw

55、are and software system, reliable work the Proteus software simulation. The basic process is first draw HaoTu 3 illustrates the simulation</p><p>　　Electricity by road after Keil soft thing, Ed into the tran

56、slation and born of dynamic soft thing ec flooding (files) : LPC2131 loaded. And Proteus software environment</p><p>　　The simulation results (" + 3V corresponding full amount 30Kpa) the process design

57、of the software and hardware the results show that the system is correct</p><p>　　To ensure that the design of the software and hardware of soil detector is correct this paper designs proteus soft thing into

58、 line imitation true. The base this process is first draw had made good figure 2 shows simulation circuit, Keil software compiled by again and to create system driver (" *. Wen pieces ") load: the monolithic ma

59、chine, and will figure 2 virtual dc voltage signal generator set to 45mV. Then the simulation of voltage: enlarge V0 = 48 x 0.045 = 2.16 V, soil relative humidity sh</p><p>　　The simulation results show that

60、 the 45.18% RH "(for" the calculation and existing tiny</p><p>　　According to convert error). The results show that the system software and hardware design are right.</p><p>　　Section6

61、 conclusion</p><p>　　This paper introduces some machine oxygen pressure detection adjustment system design of the software and hardware square method. This set with set in A project into A/D turn changing m

62、ould pieces of high sexual can LPC2131 chip, tell the plus special A/D acquisition chip, simplified the peripheral circuit design. The system design is simple in structure, reliable in trial has obtained good effect.<

63、/p><p>　　(1) this design using highly integrated humidity detector A/D conversion chip, SCM and LCD module, greatly simplifying the hardware circuit and significantly reduce the size and cost of A circuit board

64、.</p><p>　　(2) electric pressure letter in ADC0832, integrating core piece of work is really is. Ec</p><p>　　The most important premise, to ensure reliable of the analog signal collection, colle

65、ction need before use integrated amp sensor signal amplifier.</p><p>　　(3) the loam soil by small, measuring devices body product by pure degree is high and measured this very low, suitable to use of agricul

66、tural first production line.</p><p>　　(4) the system can shorten Proteus simulation designing cycle, managing hardware investment. The simulation results show that the system design is correct, reliable oper

67、ation</p><p>　　Section 7 References</p><p>　　[1] 孫余凱,吳鳴山,項(xiàng)綺明.集成運(yùn)算放大器實(shí)用電路識(shí)圖[M].北京</p><p>　　[2] 李贛平,邵惠鶴.基于 ARM 的高精度智能流量變送器的設(shè)計(jì)[J]</p><p>　　[3] 馮偉,白瑞林,李祥偉.基于 WinCE5.0 的數(shù)字式觸

68、摸屏驅(qū)動(dòng)程序的開(kāi)發(fā)[J].自動(dòng)化儀表, 2009,9.</p><p>　　[4] 張洪潤(rùn). 傳感器應(yīng)用設(shè)計(jì) 300 例（上冊(cè)）[M].北京: 北京航空航天大學(xué)出版社, 2006.</p><p>　　[5] 徐瑋. C51 單片機(jī)高效入門(mén)[M]. 北京: 機(jī)械工業(yè)出版社, 2007.</p><p>　　[6] 師寶山.基于 AT89S51 的多參數(shù)氣體檢測(cè)儀的研

69、制[J].微計(jì)算機(jī)信息, 2007, 7~1.</p><p>　　[7] 周堅(jiān).單片機(jī)輕松入門(mén)[M].北京:北京航空航天大學(xué)出版社, 2004.</p><p>　　基于 AT89S51 單片機(jī)的微型土壤濕度檢測(cè)儀設(shè)計(jì)</p><p>　　摘要： 為便于掌握土壤的濕度狀況， 設(shè)計(jì)了微型土壤濕度檢測(cè)儀。 其硬件系統(tǒng)包括信號(hào)放大電路、 A/D 轉(zhuǎn)換電路、 單片機(jī)、 微

70、型液晶顯示器和報(bào)警電路等； 軟件系統(tǒng)包括 A/D 轉(zhuǎn)換的驅(qū)動(dòng)程序 、 液晶驅(qū)動(dòng)</p><p>　　程序兩個(gè)模塊。 基于 Proteus 軟件平臺(tái)對(duì)系統(tǒng)的設(shè)計(jì)進(jìn)行了仿真， 結(jié)果表明系統(tǒng)的軟硬件設(shè)計(jì)正確，運(yùn)行可靠。</p><p>　　關(guān)鍵詞： 土壤濕度； 檢測(cè)儀； 單片機(jī)； A/D 轉(zhuǎn)換； 仿真</p><p>　　中圖分類(lèi)號(hào)： TP202</p>&

71、lt;p><b>　　文獻(xiàn)標(biāo)識(shí)碼： A</b></p><p><b>　　第一章引言</b></p><p>　　農(nóng)業(yè)生產(chǎn)在我國(guó)的經(jīng)濟(jì)發(fā)展中具有重要地位，為農(nóng)業(yè)生產(chǎn)提供及時(shí)、 可靠的技術(shù)服務(wù)已成為氣象部門(mén)的重要職責(zé)之一 。 隨著國(guó)家各級(jí)政府對(duì)農(nóng)業(yè)生產(chǎn)的日益重視，我單位也在服務(wù)農(nóng)業(yè)、 促進(jìn)農(nóng)民增收等方面開(kāi)展了許多研究 ，對(duì)農(nóng)業(yè)生產(chǎn)中的各項(xiàng)問(wèn)

72、題也進(jìn)行了廣泛調(diào)研.調(diào)研發(fā)現(xiàn)， 園藝栽培、溫室花卉、大棚蔬菜等的某些名貴品種，對(duì)土壤濕度有著極高的要求，土壤濕度不當(dāng)時(shí)，不僅嚴(yán)重影響其正常生長(zhǎng)，甚至?xí)?dǎo)致種植品死亡，造成農(nóng)民的嚴(yán)重?fù)p失。為此，從事該類(lèi)農(nóng)業(yè)生產(chǎn)的農(nóng)民朋友非常需要一種成本低、體積小且檢測(cè)可靠的土壤濕度檢測(cè)儀，為水分供應(yīng)提供依據(jù)。為了解決以上問(wèn)題，我單位結(jié)合我區(qū)農(nóng)業(yè)生產(chǎn)實(shí)際狀況，和有關(guān)單位專(zhuān)家共同設(shè)計(jì)了高精度 、低成本的微型土壤濕度檢測(cè)儀 。</p><p

73、>　　本文則詳細(xì)介紹了該檢測(cè)儀的測(cè)控電路和相關(guān)軟件流程。</p><p><b>　　第二章系統(tǒng)的組成</b></p><p>　　微型土壤檢測(cè)儀的信號(hào)處理系統(tǒng)包括土壤濕度傳感器、A/D 采集電路、單片機(jī)和微型液晶顯示器。其工作過(guò) 程 是 ：土 壤 濕 度 傳 感 器 將 濕 度 信 號(hào) 送 至 A/D 采 集 電路，經(jīng) A/D 轉(zhuǎn)換后，所得數(shù)字信號(hào)送入單片機(jī)進(jìn)

74、行數(shù)據(jù)處理，最后將處理結(jié)果發(fā)送到微型液晶顯示器顯示。</p><p>　　第三章 系統(tǒng)的硬件設(shè)計(jì)</p><p>　　3.1 電路的工作原理</p><p>　　本文所選的KSC-6V集成相對(duì)濕度傳感器插入土壤后，等待約5s使傳感器充分接觸土壤后，信號(hào) Vin 經(jīng)集成運(yùn)放 LM324 的同相輸入端。該傳感器的相對(duì)濕度 0%~100%RH 時(shí)，其對(duì)應(yīng)的輸出為 0~10

75、0mV[1]。根據(jù)集成運(yùn)放的同相比例放大增益：Kf=R1+ Rf =1+ 47 =48</p><p>　　則放大后的輸出模擬信號(hào)電壓V0=48?Vi，故輸出模擬信號(hào)電壓范圍為 0~4.8V。該模擬信號(hào)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(hào)再送入單片機(jī) AT89S51 進(jìn)行數(shù)據(jù)處理并由液晶顯示。</p><p>　　3.2 A/D 轉(zhuǎn)換芯片的選擇與控制原理<

76、/p><p>　　本文選擇的 A/D 轉(zhuǎn)換芯片為 ADC0832，該芯片為8引腳雙列直插式雙通道 A/D 轉(zhuǎn)換器，能分別對(duì)兩路模擬信號(hào)實(shí)現(xiàn) 模/數(shù) 轉(zhuǎn)換，可以用在單端輸入 方式和差分輸入方式下工作，其中DI端進(jìn)行通道選 擇、數(shù)據(jù)采集和數(shù)據(jù)傳送[2]。ADC0832的工作。根據(jù)協(xié)議，當(dāng)ADC0832 未工作時(shí)，必須將片選端 CS 置于高電平，此時(shí)芯片禁用。當(dāng)要進(jìn)行A/D 轉(zhuǎn)換時(shí)，應(yīng)將片選端CS置于低電平并保持到轉(zhuǎn)換結(jié)束

77、。芯片開(kāi)始工作后，還需讓單片機(jī)向芯片的時(shí)鐘信 號(hào)輸入端 CLK 輸入時(shí)鐘脈沖，在第一個(gè)時(shí)鐘脈沖的下沉之前 DI 端必須是 高電平，表示起始信號(hào)。在第2、3個(gè)脈沖的下沉之前DI 端則應(yīng)輸入兩位數(shù)據(jù)用于選擇通道功能。通道受控情況如下： </p><p>　　①當(dāng)DI依次輸入1、0 時(shí)，只對(duì)CH0通道進(jìn)行單通道轉(zhuǎn)換；</p><p>　?、诋?dāng)DI依次輸入1、1 時(shí)，只對(duì)CH1通道進(jìn)行單通道轉(zhuǎn)換；

78、</p><p>　　③當(dāng)DI依次輸入0、0 時(shí)，將CH0作為正輸入端 “IN+”，CH1作為負(fù)輸入端“IN-”；</p><p>　?、墚?dāng)DI依次輸入 0、1 時(shí)，將CH0作為負(fù)輸入端“IN-”，CH1作為正輸入端“IN+”。</p><p>　　在第 3 個(gè)脈沖下沉之后，DI 端的輸入電平就失去輸入作用 ，此 后數(shù)據(jù) 輸出端DO開(kāi)始輸出轉(zhuǎn)換后的數(shù)據(jù) 。</

79、p><p>　　在第4個(gè)脈沖的下降沿輸出轉(zhuǎn)換后數(shù)據(jù)的最高位，直到第11個(gè)脈沖下降沿輸出數(shù)據(jù)的最低位，至此 ，一個(gè)字節(jié)的數(shù)據(jù)輸出完成。正常情況下，ADC0832 與單片機(jī)的接口應(yīng)為4條數(shù)據(jù)線，分別是CS、CLK、DO、DI。但由于 DO 和 DI兩個(gè)端口在通信時(shí)并未同時(shí)使用，而是先由DI端口輸入兩位數(shù)據(jù)（0 或 1）來(lái)選擇通道控制，再由DO端輸出數(shù)據(jù) 。因此，在I/O 口資源緊張時(shí)，可以將 DO 和并聯(lián)在一根數(shù)據(jù)線上使

80、用。</p><p>　　3.3 單片機(jī)的選擇</p><p>　　單片機(jī)是控制記錄儀工作的核心，經(jīng)過(guò)比較采用AT89S51 型單片機(jī)。該型單片機(jī)的優(yōu)點(diǎn)是[3]：</p><p>　?、僭搯纹瑱C(jī)與 8051 系列單片機(jī)完全兼 容 ，容易使用，且成本十分低廉；</p><p>　?、趦?nèi)部存儲(chǔ)器采用可反復(fù)擦寫(xiě)的 EEPRROM，有利于反復(fù)修改程序

81、；</p><p>　?、劬哂械秃哪芄ぷ鞣绞胶湍軌?qū)崿F(xiàn)掉電自動(dòng)保護(hù)； </p><p>　　④具有較強(qiáng)的抗干擾性，大大提高了抵御外界的電磁干擾能力，所以特別適合在條件相對(duì)惡劣的條件下工作。</p><p>　　3.4 液晶顯示器的使用</p><p>　　顯示器件采用微型液晶顯示器 1602LCD，其性能特點(diǎn)是：工作電壓僅需 4.5～5.5V

82、；功耗非常低（工作電流只有 2.0mA）；且工作可靠；體積?。娠@示 16×2 個(gè)字符）。其字符顯示功能由內(nèi)部專(zhuān)用的驅(qū)動(dòng)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(chǔ)器（DDRAM），內(nèi)部控制線 路就會(huì)自動(dòng)將符傳送到顯示器上 。單片機(jī)和1602LCD之間的數(shù)據(jù)交換通過(guò)P0 進(jìn)行，電阻R2～R9為P0口的上拉電阻。</p><p>　　第四章 系統(tǒng)的控制軟件設(shè)計(jì)</p>

83、<p>　　本記錄儀的控制軟件設(shè)計(jì)采用模塊化思想</p><p>　　根據(jù)功能將系統(tǒng)控制軟件分為兩大模塊： </p><p>　?、貯DC0832的驅(qū)動(dòng)程序模塊，控制電壓信號(hào)的采集；②1602LCD 的驅(qū)動(dòng)程序</p><p>　　模塊，顯示土壤濕度。本系統(tǒng)的驅(qū)動(dòng)程序采用 C 語(yǔ)言設(shè)計(jì)，其主程序如：</p><p>　　main

84、(void)</p><p><b>　　{</b></p><p>　　unsigned int AD_val;轉(zhuǎn)換后的值</p><p>　　unsigned int Int,Dec;</p><p>　　轉(zhuǎn)換后的整數(shù)部分與小數(shù)部分</p><p><b>　　//儲(chǔ) 存 A/D&l

85、t;/b></p><p><b>　　//分 別 儲(chǔ) 存</b></p><p>　　LcdInitiate () ;</p><p>　?。?） 時(shí) 鐘 產(chǎn) 生 。時(shí)鐘分頻器（ 通過(guò)它可以得到4.5MHz 的轉(zhuǎn)換時(shí)鐘 ）在A/D 轉(zhuǎn)換器空閑時(shí)保持復(fù)位狀態(tài)，在 ADCR 的START字段被寫(xiě)入01（立即啟動(dòng)轉(zhuǎn)換）或所選邊沿出現(xiàn)在選擇的信

86、號(hào)上時(shí)可立刻啟動(dòng)采樣時(shí)鐘。</p><p>　　這個(gè)特性可以節(jié)省功耗。ADC 轉(zhuǎn)換時(shí)鐘的計(jì)算公式如下：</p><p><b>　　FADC=</b></p><p><b>　　CLKDIV+1</b></p><p>　　式 中 ：Fpclk—芯片外設(shè)時(shí)鐘；CLKDIV—分頻后的ADC轉(zhuǎn)換時(shí)鐘。

87、</p><p>　　（3）中斷。當(dāng)DONE位為1時(shí)，A/D轉(zhuǎn)換模塊向向量中斷控制器（VIC）發(fā)出中斷請(qǐng)求，如果VIC中VICIn-tEnable的Bit8（A/D 轉(zhuǎn)換中斷使能位）使能， 則會(huì)產(chǎn)生中斷。讀取 ADDR 將清零 DONE 位。</p><p>　　本文主要的 A/D 采集 C 語(yǔ)言驅(qū)動(dòng)程序段設(shè)計(jì)如下：</p><p>　　/*************

88、**********************</p><p>　　函數(shù)功能：A/D 采集</p><p><b>　　入口參數(shù)：CH_i</b></p><p>　　************************************/</p><p>　　void AD_Change(unsigned char C

89、H_i)</p><p><b>　　{</b></p><p>　　ADC0R=(1<<CH_i) | //選擇通道 i 進(jìn)行 A/D 采集</p><p>　　((Fpclk/1000000-1)<<8 | //設(shè)置轉(zhuǎn)換時(shí)鐘</p><p><b>　?。?<<16）&

90、lt;/b></p><p><b>　?。?<<19）</b></p><p>　　| //BURST=0，軟件控制轉(zhuǎn)換操作</p><p>　　| //正常 A/D 采集模式</p><p>　　0<<27）; | //下降沿啟動(dòng)轉(zhuǎn)換</p><p>　　

91、DO =AD0DR; //讀 取 ADC 結(jié) 果 ， 并 清 除</p><p><b>　　DONE 標(biāo)志位</b></p><p>　　第五章 測(cè)溫系統(tǒng)的 Proteus 軟件仿真</p><p>　　為確保系統(tǒng)的可靠工作， 對(duì)軟硬件系統(tǒng)進(jìn)行了 Proteus 軟件仿真。 其基本過(guò)程是先繪制好圖 3 所示的仿真電 路 后 ， 將

92、由 Keil 軟 件 編 譯 并 生 成 的 系 統(tǒng) 驅(qū) 動(dòng) 軟 件（hex 文件）載入 LPC2131。 并在 Proteus 軟件環(huán)境中， 在Vin 端口輸入電壓 “V=+3V”， 啟動(dòng)仿真 </p><p>　　為確保土壤檢測(cè)儀的軟硬件設(shè)計(jì)正確，本文對(duì)設(shè)計(jì)進(jìn)行了 Proteus 軟 件 仿真。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(dòng) 程序 （“*.hex 文 件 ”） 載 入 單 片 機(jī)

93、，并 將圖 2 中 的 虛擬直流電壓信號(hào)發(fā)生器設(shè)為 45mV。 則其放大后的模擬電壓： V0=48×0.045=2.16V， 土壤的相對(duì)濕度應(yīng)為： RH=2.16 ×100=45%RH。 啟動(dòng)仿真即可看到圖 2 中 1602LCD4.8上的仿真結(jié)果顯示為“45.18%RH”（存在微小的計(jì)算和數(shù)據(jù)轉(zhuǎn)換誤差） 該結(jié)果表明，系統(tǒng)的軟、硬件設(shè)計(jì)正確。</p><p><b>　　第六章 結(jié)論

94、</b></p><p>　　本文介紹了某機(jī)氧氣調(diào)節(jié)系統(tǒng)壓力檢測(cè)的軟硬件設(shè)計(jì)方法 。該設(shè)計(jì)采用集 成有A/D轉(zhuǎn)換模塊的高性能LPC2131 芯片，省去了外加專(zhuān)用 A/D 采集芯片， 簡(jiǎn)化了外圍電路設(shè)計(jì)。系統(tǒng)整體設(shè)計(jì)結(jié)構(gòu)簡(jiǎn)單，運(yùn)行可靠，在試用中取得了良好效果。</p><p><b>　　第七章 參考文獻(xiàn)</b></p><p>　　

95、[1]孫余凱,吳鳴山,項(xiàng)綺明.集成運(yùn)算放大器實(shí)用電路識(shí)圖[M].北京:電子工業(yè)出版社,2008.</p><p>　　[2]李贛平,邵惠鶴.基于ARM 的高精度智能流量變送器的設(shè)計(jì)[J].電子技術(shù)應(yīng)用,2008,12.</p><p>　　[3] 馮偉,白瑞林,李祥偉.基于 WinCE5.0 的數(shù)字式觸摸屏驅(qū)動(dòng)程序的開(kāi)發(fā)[J].自動(dòng)化儀表, 2009,9.</p><p

96、>　　[4] 張洪潤(rùn). 傳感器應(yīng)用設(shè)計(jì) 300 例（上冊(cè)）[M].北京: 北京航空航天</p><p>　　大學(xué)出版社, 2006.</p><p>　　[5] 徐瑋. C51 單片機(jī)高效入門(mén)[M]. 北京: 機(jī)械工業(yè)出版社, 2007.</p><p>　　[6] 師寶山.基于 AT89S51 的多參數(shù)氣體檢測(cè)儀的研制[J].微計(jì)算機(jī)</p>