外文翻譯---無(wú)線傳感器網(wǎng)絡(luò)的實(shí)現(xiàn)及在農(nóng)業(yè)上的應(yīng)用

1、<p>　　附錄Ⅰ 外文文獻(xiàn)原文、譯文</p><p>　　The realization of wireless sensor networks and applications in agriculture</p><p>　　1 Introduction</p><p>　　Wireless sensor networks (Wireless Sen

2、sor Network, WSN) are deployed in the monitoring area by the large number of low-cost micro sensor nodes, wireless communication through the formation of a multi-hop network self-organization. The aim is to perceive coll

3、aboration, collection and processing of network coverage in the perception of objects, and send observers. "Sensors, sensing object and the observer," constitute the three elements of the network. Here that the

4、 sensor is not in the traditiona</p><p>　　2 Overview of wireless sensor networks</p><p>　　2.1 The system architecture of wireless sensor networks</p><p>　　Wireless sensor network sy

5、stem architecture shown in Figure 1, typically include sensor nodes, aggregation nodes and management nodes. Clouds in the observation area sensor nodes in order to constitute a network of self-organized manner. Sensor n

6、ode processing the collected information, the way to multi-hop relay the information transmitted to the sink node. Then through the Internet or mobile communication network and other channels to reach management node. En

7、d-users through the management of </p><p>　　2.2 The characteristics of wireless sensor networks</p><p>　　(1) self-organization. As the network and the network itself, the physical environment in

8、 which the unpredictability of factors, such as: can not pre-set exact location of the node can not know in advance the relationship between the nodes adjacent to some nodes because of energy depletion or other causes of

9、 death, newnodes join and so on, make the network deployment and expansion without the need to rely on any of the default network infrastructure, layered protocol between nodes and distribute</p><p>　　(2) mu

10、lti-hop routing. Limited communication distance of nodes in the network, the node can only communicate directly with its neighbors, if beyond the range of its RF communication nodes, you need to be routed through interme

11、diate nodes.</p><p>　　(3) the spatial distribution of a large area, node density, the number is huge.</p><p>　　(4) data-center. In wireless sensor networks, people usually only care about a regi

12、on within a certain numerical observations, and not to the specific observations concerned a single node.</p><p>　　(5) Node capacity constraints. The energy of sensor nodes, processing power, storage capacit

13、y and communication ability and so is very limited.</p><p>　?、?Power energy restricted. As the miniaturization of sensor nodes, node battery power is limited, and because physical constraints make it difficu

14、lt for nodes to replace the battery, so battery power limitations of sensor nodes is the wireless sensor network design one of the most critical constraints, which directly determines the network's worklife.</p>

15、;<p>　?、?computing and storage capacity is limited.Bring low-cost micro sensor nodes weak processor, memory capacity of small features, so it can not perform complex calculations, and the traditional Internet netw

16、ork protocols and algorithms on the relative maturity of wireless sensor networks, too costly, difficult to use,must therefore be simple, effective protocols and algorithms, such as the ZigBee protocol.</p><p&

17、gt;　?、?communication is limited.Typically, the energy consumption of wireless communication and communication distance d E the relation: E = kdn.Where 2 <n <4.N is usually taken as 3.</p><p>　　2.3 The

18、shortcomings of wireless sensor networks</p><p>　　(1) energy is limited. Sensor nodes are usually powered by ordinary batteries or lithium batteries, the energy limited.In unattended environments, wireless s

19、ensor network applications is one of the bottlenecks.</p><p>　　(2) node cost is higher. Currently on the market price in thousands of sensor nodes over the wireless sensor network nodes need many, limiting p

20、romote the use of wireless sensor networks.</p><p>　　(3) The poor security. As a result of wireless channel, distributed control technology, the network more vulnerable to passive eavesdropping, active intru

21、sion and other attacks.</p><p>　　(4) collaboration. Individual sensor nodes are often unable to complete the target of measurement, tracking and recognition, while the number of sensor nodes need to exchange

22、 information through the algorithm on data obtained for processing, aggregation and filtering, the final result.</p><p>　　3 the current wireless sensor network applications in agriculture</p><p>

23、;　　View of the water shortage and the demand for farmland irrigation, irrigation equipment under the existing conditions of application fields of crops, soil, water distribution, etc., for precise analysis of the current

24、 agricultural solved key technical problems, we propose a use ofwireless sensor network technology, suitable for large areas of agricultural land Intelligent Irrigation Control.3.1 The system works</p><p>　

25、　Of SCM system with multiple sensors on the humidity, temperature, rainfall, pH, water evaporation (wind speed) and air temperature, and other information collection to achieve the precise automatic irrigation control fi

26、eld, the output of the signal information through a wireless full-dup lex Public data transmission sent to the control center transceiver module (embedded systems) to determine whether to activate the pump for the farm w

27、ater supply, water supply or not, this same information sent </p><p>　　Wireless sensor network model is different from the traditional wireless network infrastructure, network, monitoring the region by a lar

28、ge number of sensor nodes randomly dispenser (the node), coordinated by the node and quickly set up their own communications network, under the principle of priority for energy efficiency division of work tasks for monit

29、oring regional information .Self-organizing properties of the network when the node failure is reflected in the new node is added or when the ne</p><p>　　In this system, the control network and Internet host

30、s as the connection between the wireless sensor network protocol conversion gateway. The hardware used Zhiyuan Electronics Mini ARM embedded computer modules. MiniISA series acquisition board structure using smart card,

31、that card on the built-in MCU.MCU on the board on-board I / O ports control, to achieve I / O data buffer, thereby reducing the interface to the host board for Mini ISA dependence, saving the host data processing time, t

32、o ensur</p><p>　　Concluding Remarks</p><p>　　This paper reviews the nodes of wireless sensor networks, characteristics, and current applications in agriculture, research-based embedded systems,

33、intelligent wide are a of farmland out of the water supply system, water is detected field information to continue through the automatic control Electric water pump to start, and realized the remote GPRS communications,

34、PC, to learn through the health system and over which it controlled, automatic acquisition of soil information to determine whether</p><p>　　Today's wireless sensor network as a new hotspot in the field

35、of information, involving inter disciplinary. With the reduced cost sensors and related solutions to continuous optimization problems, such as power consumption and data fusion algorithm is more small, node localization

36、algorithm in continuous improvement, and more advanced wireless RF module, wireless sensor networks will be more in agriculture wide range of applications.</p><p>　　1 microcontroller features of the developm

37、ent of technology </p><p>　　SCM has been there since, SCM technology has gone through nearly 20 years of development journey. Throughout the past 20 years of SCM Exhibition history we can see that the SCM te

38、chnology to the development of the microprocessor (MPU) technology and ultra-large-scale integrated circuit technology for the Exhibition for the pilot to pull a wide range of applications, showing more personality than

39、the microprocessor trend of development： SCM long life here said the long-life, on the one hand r</p><p>　　Of growth SCM faster development in the MPU demonstrated by the faster clock frequency is increa

40、sing as the hallmark.The SCM is different, to enhance SCM anti-disturbance capacity, lower noise and lower clock frequency without sacrifice SCM offerings computing speed is the pursuit of technological development.8051

41、MCU with some manufacturers to improve the internal when the MCU Sequence, without raising the clock frequency of conditions, to raise a lot faster, Motorola MCU is used Suo Ring of te</p><p>　　2 A wide sele

42、ction of SCM </p><p>　　SCM Motorola Motorola is the world's largest manufacturers of SCM. All varieties, choice, new products Many of its features, there are eight of 68 HC05 and upgrading of products 6

43、8 HC08, 68HC05 have more than 30 series, more than 200 Varieties, production has more than 2 billion. 8 enhanced MCU 68 HC11 has more than 30 varieties, 100 million in annual output Upgrading of products are 68 HC12. 16

44、crew 68 HC16 has over 10 varieties. 32 SCM 683 XX series also There are dozens of varieties. In rece</p><p>　　Zilog microcontroller is Zilog Z8 microcontroller company's products, a multi-accumulator st

45、ructure, have a stronger will interrupt handling OTP-based products, Z8 microcontroller development tools that can be cheap. Z8 microcontroller to low-cost advantage for low -Client applications, mainly to 18-pin package

46、, ROM for the 0.5 ~ 2 K. Zilog companies have also recently introduced the Z86 series of SCM, The series can be integrated within the DSP units cheap. NS MCU MCU is COP8 National Semic</p><p>　　無(wú)線傳感器網(wǎng)絡(luò)的實(shí)現(xiàn)

47、及在農(nóng)業(yè)上的應(yīng)用</p><p><b>　　1引言</b></p><p>　　無(wú)線傳感器網(wǎng)絡(luò)（Wireless Sensor Network ,WSN）就是由部署在監(jiān)測(cè)區(qū)域內(nèi)大量的廉價(jià)微型傳感器節(jié)點(diǎn)組成，通過(guò)無(wú)線通信方式形成的一個(gè)多跳的自組織的網(wǎng)絡(luò)系統(tǒng)。其目的是協(xié)作地感知、采集和處理網(wǎng)絡(luò)覆蓋區(qū)域中感知對(duì)象的信息，并發(fā)送給觀察者?！皞鞲衅?、感知對(duì)象和觀察者”構(gòu)成了網(wǎng)

48、絡(luò)的三個(gè)要素。這里說(shuō)的傳感器，并不是傳統(tǒng)意義上的單純的對(duì)物理信號(hào)進(jìn)行感知并轉(zhuǎn)化為數(shù)字信號(hào)的傳感器，它是將傳感器模塊、數(shù)據(jù)處理模塊和無(wú)線通信模塊集成在一塊很小的物理單元，即傳感器節(jié)點(diǎn)上，功能比傳統(tǒng)的傳感器增強(qiáng)了許多，不僅能夠?qū)Νh(huán)境信息進(jìn)行感知，而且具有數(shù)據(jù)處理及無(wú)線通信的功能。借助傳感器節(jié)點(diǎn)中內(nèi)置的形式多樣的傳感器件，可以測(cè)量所在環(huán)境中的熱、紅外、聲納、雷達(dá)和地震波信號(hào)等信號(hào)，從而探測(cè)包括溫度、濕度、噪聲、光強(qiáng)度、壓力、土壤成分、移動(dòng)物體

49、的大小、速度和方向等等眾多我們感興趣的物質(zhì)現(xiàn)象。無(wú)線傳感器網(wǎng)絡(luò)是一種全新的信息獲取和信息處理模式。由于我國(guó)水資源已處于相當(dāng)緊缺的程度,加上全國(guó)90%的廢、污水未經(jīng)處理或處理未達(dá)標(biāo)就直接排放的水污染,11%的河流水質(zhì)低于農(nóng)田供水標(biāo)準(zhǔn)。水是農(nóng)業(yè)的命脈,是生態(tài)環(huán)境的控制性要素,</p><p>　　2無(wú)線傳感器網(wǎng)絡(luò)概述</p><p>　　2.1無(wú)線傳感器網(wǎng)絡(luò)的系統(tǒng)架構(gòu)</p>&

50、lt;p>　　無(wú)線傳感器網(wǎng)絡(luò)的系統(tǒng)架構(gòu)如圖1所示，通常包括傳感器節(jié)點(diǎn)、匯聚節(jié)點(diǎn)和管理節(jié)點(diǎn)。傳感器節(jié)點(diǎn)密布于觀測(cè)區(qū)域，以自組織的方式構(gòu)成網(wǎng)絡(luò)。傳感器節(jié)點(diǎn)對(duì)所采集信息進(jìn)行處理后，以多跳中繼方式將信息傳輸?shù)絽R聚節(jié)點(diǎn)。然后經(jīng)由互聯(lián)網(wǎng)或移動(dòng)通信網(wǎng)絡(luò)等途徑到達(dá)管理節(jié)點(diǎn)。終端用戶可以通過(guò)管理節(jié)點(diǎn)對(duì)無(wú)線傳感器網(wǎng)絡(luò)進(jìn)行管理和配置、發(fā)布監(jiān)測(cè)任務(wù)或收集回傳數(shù)據(jù)。</p><p>　　圖2.1無(wú)線傳感器網(wǎng)絡(luò)的系統(tǒng)架構(gòu)</p&

51、gt;<p>　　2.2無(wú)線傳感器網(wǎng)絡(luò)的特點(diǎn)</p><p>　?。?）自組織。由于網(wǎng)絡(luò)所處物理環(huán)境及網(wǎng)絡(luò)本身的不可預(yù)測(cè)因素，如：不能預(yù)先精確設(shè)定節(jié)點(diǎn)的位置，也不能預(yù)先知道節(jié)點(diǎn)之間的相鄰關(guān)系，部分節(jié)點(diǎn)由于能量耗盡或其他原因而死亡，新的節(jié)點(diǎn)的加入等，使得網(wǎng)絡(luò)的布設(shè)和展開(kāi)能夠無(wú)需依賴于任何預(yù)設(shè)的網(wǎng)絡(luò)設(shè)施，節(jié)點(diǎn)之間通過(guò)分層協(xié)議和分布式算法協(xié)調(diào)各自的行為，節(jié)點(diǎn)開(kāi)機(jī)后就可以快速自動(dòng)地組成一個(gè)獨(dú)立的網(wǎng)絡(luò)多跳路由

52、。</p><p>　?。?）多跳路由。網(wǎng)絡(luò)中節(jié)點(diǎn)通信距離有限,節(jié)點(diǎn)只能與它的鄰居直接通信，如果與其射頻覆蓋范圍之外的節(jié)點(diǎn)進(jìn)行通信，則需要通過(guò)中間節(jié)點(diǎn)進(jìn)行路由。</p><p>　?。?）大面積的空間分布，節(jié)點(diǎn)密集，數(shù)量巨大。</p><p>　?。?）以數(shù)據(jù)為中心。在無(wú)線傳感器網(wǎng)絡(luò)中，人們通常只關(guān)心某個(gè)區(qū)域內(nèi)某個(gè)觀測(cè)指標(biāo)的數(shù)值，而不會(huì)去具體關(guān)心單個(gè)節(jié)點(diǎn)的觀測(cè)數(shù)據(jù)。

53、</p><p>　?。?）節(jié)點(diǎn)能力受限。傳感器節(jié)點(diǎn)的能量、處理能力、存儲(chǔ)能力和通信能力等都十分有限。</p><p>　?、匐娫茨芰渴芟蕖Ｓ捎趥鞲衅鞴?jié)點(diǎn)的微型化，節(jié)點(diǎn)的電池能量有限，而且由于物理限制難以給節(jié)點(diǎn)更換電池，所以傳感器節(jié)點(diǎn)的電池能量限制是整個(gè)無(wú)線傳感器網(wǎng)絡(luò)設(shè)計(jì)最關(guān)鍵的約束之一，它直接決定了網(wǎng)絡(luò)的工作壽命。</p><p>　?、谟?jì)算和存儲(chǔ)能力有限。廉價(jià)微

54、型的傳感器節(jié)點(diǎn)帶來(lái)了處理器能力弱、存儲(chǔ)器容量小的特點(diǎn)，使得其不能進(jìn)行復(fù)雜的計(jì)算，而傳統(tǒng)Internet網(wǎng)絡(luò)上成熟的協(xié)議和算法相對(duì)無(wú)線傳感器網(wǎng)絡(luò)而言開(kāi)銷太大，難以使用，因此必須使用簡(jiǎn)單、有效的協(xié)議及算法，如ZigBee協(xié)議。</p><p>　?、弁ㄐ拍芰τ邢蕖Ｍǔ?，無(wú)線通信的能耗E與通信距離d的關(guān)系為：E=kdn。其中2<n<4。通常取n為3。</p><p>　　2.3無(wú)線傳

55、感器網(wǎng)絡(luò)存在的不足</p><p>　?。?）能量受限。傳感器節(jié)點(diǎn)通常由普通電池或鋰電池供電，能量有限。在無(wú)人值守的環(huán)境中，也是無(wú)線傳感器網(wǎng)絡(luò)應(yīng)用的瓶頸之一。</p><p>　?。?）節(jié)點(diǎn)成本較高。目前市面上銷售的傳感器節(jié)點(diǎn)價(jià)格在千元以上，而無(wú)線傳感器網(wǎng)絡(luò)所需要的節(jié)點(diǎn)眾多，因此限制了無(wú)線傳感器網(wǎng)絡(luò)的推廣使用。</p><p>　?。?）安全性差。由于采用了無(wú)線信道

56、、分布式控制等技術(shù)，網(wǎng)絡(luò)更容易受到被動(dòng)竊聽(tīng)、主動(dòng)入侵等攻擊。</p><p>　?。?）協(xié)作能力。單個(gè)的傳感器節(jié)點(diǎn)往往不能完成對(duì)目標(biāo)的測(cè)量、跟蹤和識(shí)別，而需要多個(gè)傳感器節(jié)點(diǎn)通過(guò)算法交換信息，對(duì)所獲得的數(shù)據(jù)進(jìn)行加工、匯總和過(guò)濾，得到最終結(jié)果。</p><p>　　3 無(wú)線傳感器網(wǎng)絡(luò)當(dāng)前在農(nóng)業(yè)中的應(yīng)用</p><p>　　針對(duì)我國(guó)水資源緊缺以及農(nóng)田節(jié)水灌溉的需求,根據(jù)現(xiàn)

57、有的農(nóng)田灌溉裝備條件,應(yīng)用領(lǐng)域作物、土壤、水源布點(diǎn)等情況,分析了目前實(shí)現(xiàn)精確農(nóng)業(yè)亟待解決的關(guān)鍵技術(shù)問(wèn)題,提出一套采用無(wú)線傳感器網(wǎng)絡(luò)技術(shù)、適合大面積農(nóng)田智能灌溉控制方法。</p><p>　　3.1　系統(tǒng)工作原理</p><p>　　研究單片機(jī)系統(tǒng)通過(guò)多個(gè)傳感器對(duì)濕度、溫度、降雨量、酸堿度、水分蒸發(fā)量(風(fēng)速)和空氣溫度等多種信息的采集來(lái)實(shí)現(xiàn)對(duì)農(nóng)田的精確自動(dòng)灌溉控制,輸出的信號(hào)信息通過(guò)無(wú)線全雙

58、工數(shù)傳收發(fā)模塊傳送給控制中心(嵌入式系統(tǒng))來(lái)確定是否啟動(dòng)水泵為農(nóng)田供水,同時(shí)將此供水與否信息由GPRS通信通過(guò)Internet傳送到遠(yuǎn)方控制中心實(shí)現(xiàn)遠(yuǎn)程監(jiān)控,并通過(guò)計(jì)算機(jī)中的一些模型來(lái)處理信息,做出供水計(jì)劃。</p><p>　　3.2　無(wú)線傳感器網(wǎng)絡(luò)硬件設(shè)計(jì)</p><p>　　無(wú)線傳感器網(wǎng)絡(luò)模型是不同于傳統(tǒng)無(wú)線網(wǎng)絡(luò)的基礎(chǔ)設(shè)施網(wǎng),通過(guò)在監(jiān)測(cè)區(qū)域內(nèi)隨意布撒大量傳感器節(jié)點(diǎn)(簡(jiǎn)稱節(jié)點(diǎn)),由各節(jié)

59、點(diǎn)自行協(xié)調(diào)并迅速組建通信網(wǎng)絡(luò),在能量利用率優(yōu)先考慮原則下進(jìn)行工作任務(wù)劃分以獲取監(jiān)視區(qū)域信息。網(wǎng)絡(luò)的自組織特性體現(xiàn)在當(dāng)節(jié)點(diǎn)失效或新節(jié)點(diǎn)加入時(shí)網(wǎng)絡(luò)能夠自適應(yīng)重新組建,以調(diào)整全局的探測(cè)精度,充分發(fā)揮資源優(yōu)勢(shì),即網(wǎng)絡(luò)中的各節(jié)點(diǎn)除具備數(shù)據(jù)采集功能外兼有數(shù)據(jù)轉(zhuǎn)發(fā)實(shí)現(xiàn)多跳的路由功能。無(wú)線傳感器網(wǎng)絡(luò)每類節(jié)點(diǎn)的組成一般都由數(shù)據(jù)采集、數(shù)據(jù)處理、數(shù)據(jù)傳輸和電源這四部分組成。其中每一個(gè)單片機(jī)系統(tǒng)的硬件設(shè)計(jì)和軟件設(shè)計(jì)都是一樣。本設(shè)計(jì)的研究設(shè)計(jì)方案是只針對(duì)一個(gè)單片

60、機(jī)系統(tǒng)的。被監(jiān)測(cè)物理信號(hào)的形式?jīng)Q定了傳感器的類型。處理器通常選用嵌入式CPU,如MOTOROLA公司的68HC16、C51系列單片機(jī)等。數(shù)據(jù)傳輸單元可以選擇由低功耗、短距離的無(wú)線通信模塊組成,但考慮防盜與自然損壞,本系統(tǒng)選擇功耗較大、傳輸距離較遠(yuǎn)的SA68D21DL,農(nóng)民可以在辦公室或家中安放主控制器。圖2描述了節(jié)點(diǎn)的組成,其中,箭頭的方向表示數(shù)據(jù)在節(jié)點(diǎn)中的流動(dòng)方向。</p><p>　　圖3.1　傳感器網(wǎng)絡(luò)框圖

61、</p><p><b>　　3.3　主控系統(tǒng)</b></p><p>　　在該系統(tǒng)中,控制主機(jī)作為連接Internet網(wǎng)和無(wú)線傳感器網(wǎng)絡(luò)之間的協(xié)議轉(zhuǎn)換網(wǎng)關(guān)。其硬件采用致遠(yuǎn)電子公司MiniARM嵌入式工控模塊。MiniISA系列采集板卡采用智能型板卡結(jié)構(gòu),即在板卡上內(nèi)置MCU。板載MCU對(duì)板卡上I/O端口進(jìn)行控制,實(shí)現(xiàn)I/O數(shù)據(jù)的緩存,從而降低板卡對(duì)于MiniISA接

62、口主機(jī)的依賴,節(jié)省主機(jī)處理數(shù)據(jù)的時(shí)間,保證MiniISA系統(tǒng)更加高效的運(yùn)行。此外板載MCU可以對(duì)采集的數(shù)據(jù)或者輸出數(shù)據(jù)進(jìn)行進(jìn)一步的處理。系統(tǒng)電路圖如圖3所示。 </p><p>　　圖3.2主控系統(tǒng)結(jié)構(gòu)圖</p><p>　　3.4遠(yuǎn)程控制系統(tǒng)主要設(shè)計(jì)</p><p>　　GPRS通信系統(tǒng)、GPRS與Internet網(wǎng)絡(luò)接入系統(tǒng)、

63、監(jiān)控中心主機(jī)友好界面顯示控制系統(tǒng)。這一部分硬件部分可以應(yīng)用現(xiàn)有的移動(dòng)公司與電信等互聯(lián)網(wǎng)資源,軟件考慮成本和專業(yè)功能可以自主開(kāi)發(fā),建議應(yīng)用現(xiàn)有遠(yuǎn)程軟件,如《波爾遠(yuǎn)程控制》軟件、湖南省遠(yuǎn)程監(jiān)控設(shè)備有限公司的RC-2000可視化遠(yuǎn)程控制軟件系統(tǒng)。</p><p><b>　　結(jié)　語(yǔ)</b></p><p>　　本文綜述了無(wú)線傳感器網(wǎng)絡(luò)的節(jié)點(diǎn)構(gòu)成、特點(diǎn)，以及當(dāng)前在農(nóng)業(yè)領(lǐng)域的應(yīng)

64、用,研究了基于嵌入式系統(tǒng)而設(shè)計(jì)出來(lái)的智能廣域農(nóng)田供水系統(tǒng),當(dāng)檢測(cè)到農(nóng)田缺水信息時(shí)能夠通過(guò)自動(dòng)控制繼電器來(lái)啟動(dòng)供水水泵,而且實(shí)現(xiàn)了遠(yuǎn)程GPRS通信,可以通過(guò)PC機(jī)來(lái)了解系統(tǒng)的運(yùn)行狀況并可對(duì)其控制,能夠自動(dòng)采集土壤信息來(lái)自行確定是否啟動(dòng)水泵為農(nóng)田供水,這正符合我國(guó)農(nóng)村的基本國(guó)情。本系統(tǒng)操作簡(jiǎn)單,對(duì)系統(tǒng)改造一下,可以設(shè)計(jì)成庭院自動(dòng)供水系統(tǒng)、溫室自動(dòng)供水系統(tǒng)和花園自動(dòng)供水系統(tǒng)等,故本系統(tǒng)的可擴(kuò)展性比較好,前景比較廣闊。</p>&

65、lt;p>　　無(wú)線傳感器網(wǎng)絡(luò)作為當(dāng)今信息領(lǐng)域新的研究熱點(diǎn)，涉及多學(xué)科交叉。隨著傳感器成本的降低以及相關(guān)問(wèn)題解決方案的不斷優(yōu)化，如能耗更加小和數(shù)據(jù)融合算法、節(jié)點(diǎn)定位算法的不斷完善，以及更加優(yōu)秀的無(wú)線射頻模塊，無(wú)線傳感器網(wǎng)絡(luò)將會(huì)在農(nóng)業(yè)領(lǐng)域有更廣泛的應(yīng)用。</p><p>　　單片機(jī)技術(shù)的發(fā)展特點(diǎn) </p><p>　　自單片機(jī)出現(xiàn)至今，單片機(jī)技術(shù)已走過(guò)了近20年的發(fā)展路程。縱觀20年來(lái)

66、單片機(jī)發(fā)展歷程可以看出，單片機(jī)技術(shù)的發(fā)展以微處理器(MPU)技術(shù)及超大規(guī)模集成電路技術(shù)的發(fā)展為先導(dǎo)，以廣泛的應(yīng)用領(lǐng)域拉動(dòng)，表現(xiàn)出較微處理器更具個(gè)性的發(fā)展趨勢(shì)。 單片機(jī)長(zhǎng)壽命 這里所說(shuō)的長(zhǎng)壽命，一方面指用單片機(jī)開(kāi)發(fā)的產(chǎn)品可以穩(wěn)定可靠地工作十年、二十年，另一方面是指與微處理器相比的長(zhǎng)壽命。隨著半導(dǎo)體技術(shù)的飛速發(fā)展，MPU更新?lián)Q代的速度越來(lái)越快，以386、486、586為代表的MPU，很短的時(shí)間內(nèi)就被淘汰出 局，而傳統(tǒng)的單片機(jī)如68

67、HC05、8051等年齡已有15歲，產(chǎn)量仍是上升的。這一方面是由于其對(duì)相應(yīng)應(yīng)用領(lǐng)域的適應(yīng)性，另一方面是由于以該類CPU為核心，集成以更多I/O功能模塊的新單片機(jī)系列層出不窮?？梢灶A(yù)見(jiàn)，一些成功上市的相對(duì)年輕的CPU核心，也會(huì)隨著I/O功能模塊的不斷豐富，有著相當(dāng)長(zhǎng)的生存周期。新的CPU類型的加盟,使單片機(jī)隊(duì)伍 不斷壯大,給用戶帶來(lái)了更多的選擇余地。 8位、16位、32位單片機(jī)共同發(fā)展，這是當(dāng)前單片機(jī)技術(shù)發(fā)展的另一動(dòng)向。長(zhǎng)期以來(lái)

68、，單片機(jī)技術(shù)的發(fā)展是以8位機(jī)為主的。隨著移動(dòng)通訊、網(wǎng)</p><p>　　OTP與掩膜 OTP是一次性寫(xiě)入的單片機(jī)。過(guò)去認(rèn)為一個(gè)單片機(jī)產(chǎn)品的成熟是以投產(chǎn)掩膜型單片機(jī)為標(biāo)志的。由于掩膜需要一定的生產(chǎn)周期，而OTP型單片機(jī)價(jià)格不斷下降，使得近年來(lái)直接使用OTP完成最終產(chǎn)品制造更為流行。它較之掩膜具有生產(chǎn)周期短、風(fēng)險(xiǎn)小的特點(diǎn)。近年來(lái)，OTP型單片機(jī)需量大幅度上揚(yáng)，為適應(yīng)這種需求許多單片機(jī)都采用了在片編程技術(shù)(In Sy

69、stem Programming)。未編程的OTP芯片可采用裸片Bonding技術(shù)或表面貼技術(shù)，先焊在印刷板上，然后通過(guò)單片機(jī)上引出的編程線、串行數(shù)據(jù)、時(shí)鐘線等對(duì)單片機(jī)編程。解決了批量寫(xiě)OTP 芯片時(shí)容易出現(xiàn)的芯片與寫(xiě)入器接觸不好的問(wèn)題。使OTP的裸片得以廣泛使用，降低了產(chǎn)品的成本。編程線與I/O線共用，不增加單片機(jī)的額外引腳。而一些生產(chǎn)廠商推出的單片機(jī)不再有掩膜型，全部為有ISP功能的OTP。 MTP向OTP挑戰(zhàn) MTP是可

70、多次編程的意思。一些單片機(jī)廠商以MTP的性能、OTP的價(jià)位推出他們的單片機(jī)，如ATMEL AVR單片機(jī)，片內(nèi)采用FLASH，可多次編程。華邦公司生產(chǎn)的與8051兼容的單片機(jī)也采用了MTP性能，OTP的價(jià)位。這些單片機(jī)都</p><p><b>　　單片機(jī)的廣泛選擇</b></p><p>　　Motorola單片機(jī) Motorola是世界上最大的單片機(jī)廠商。品種全、選

71、擇余地大、新產(chǎn)品多是其特點(diǎn)，在8位機(jī)方面有68HC05和升級(jí)產(chǎn)品68HC08，68HC05有三十多個(gè)系列，二百多個(gè)品種，產(chǎn)量已超過(guò)20億片。8位增強(qiáng)型單片機(jī)68HC11也有三十多個(gè)品種，年產(chǎn)量在1億片以上。升級(jí)產(chǎn)品有68HC12。16位機(jī)68HC16也有十多個(gè)品種。32位單片機(jī)的683XX系列也有幾十個(gè)品種。近年來(lái)，以PowerPC、Coldfire、M.CORE 等為CPU。將DSP做為輔助模塊集成的單片機(jī)也紛紛推出。目前仍是單片機(jī)的

72、首選牌品。Motorola單片機(jī)特點(diǎn)之一是在同樣速度下所用的時(shí)鐘頻率較Intel類單片機(jī) 低很多，因而使得高頻噪聲低，抗干擾能力強(qiáng),更適合用于工控領(lǐng)域及惡劣的環(huán)境。Motorola 8位單片機(jī)過(guò)去的策略是以掩膜為主的，最近推出OTP計(jì)劃以適應(yīng)單片機(jī)發(fā)展新趨勢(shì)，在32位機(jī)上，M.CORE在性能和功耗方面都勝過(guò)ARM7。 Microchip單片機(jī) Microship單片機(jī)是市場(chǎng)份額增長(zhǎng)最快的單片機(jī)。它的主要產(chǎn)品是16C系列8位單片

73、機(jī)，CPU采用RISC結(jié)構(gòu)，僅33條指令，運(yùn)</p><p>　　華邦單片機(jī) 華邦單片機(jī)屬8051類單片機(jī)，它們的W78系列與標(biāo)準(zhǔn)的8051兼容，W77系列位增強(qiáng)型51系列，對(duì)8051的時(shí)序作了改進(jìn)。同樣時(shí)鐘頻率下速度提高2.5倍，F(xiàn)LASH容量從4K到64K，有ISP功能。在4位單片機(jī)方面華邦有921系列和帶LCD驅(qū)動(dòng)的741系列。在32K機(jī)方面，華邦使用惠普公司PA－RISC單片機(jī)技術(shù)，生產(chǎn)低位的32位RIS

74、C單片機(jī)。 以上提到的單片機(jī)廠商是進(jìn)入中國(guó)市場(chǎng)的單片機(jī)廠商的一部分，還有很多著名的單片機(jī)制造商如三菱、日立、TI等本文沒(méi)有提到?？傮w上看，美國(guó)著名公司的單片機(jī)技術(shù)仍處在領(lǐng)先的地位，特別是在高端產(chǎn)品方面，高性能的單片機(jī)新產(chǎn)品不斷推出。而日本在單片機(jī)制造業(yè)方面有也相當(dāng)?shù)膬?yōu)勢(shì)，也在積極爭(zhēng)奪家電產(chǎn)品的大客戶。韓國(guó)及我國(guó)臺(tái)灣省的一些公司在引進(jìn)消化美國(guó)技術(shù)的基礎(chǔ)上，以低價(jià)位的兼容產(chǎn)品搶占中國(guó)市場(chǎng)。而至今還沒(méi)有一家中國(guó)大陸的公司能在如此浩大