【正文】 of the position of Memory constitutes a storage medium, at present mainly of semiconductor devices and magnetic materials. The smallest memory storage unit is a bistable semiconductor circuit or a CMOS transistor, or magnetic storage element, which can store a binary code. By a number of storage element of a memory cell, and then by a number of memory cells to form a memory. A memory that contains a number of storage units, each memory cell can store a byte. The location of each memory cell has a number, that is, address, generally expressed in hexadecimal. A memory storage unit to store all data as the sum of its storage capacity. Assumes that a memory address code from the binary number 20 (that is, hexadecimal number 5) of the 220 can be said, that is, a memory cell address 1M. Each memory cell storing a single byte, the memory storage capacity of 1KB. Memory hierarchy Close in accordance with the degree of CPU, memory is divided into inner and outer storage memory, referred to as memory and OutofCore. Also often referred to as memory within main memory (referred to as main memory), are an integral part of the host。 features: integrated highcapacity, small size, fast access, low power consumption, cheap, simple to maintain. Two main categories: bipolar memory: TTL and ECL type. Memory metaloxide semiconductor (MOS memory): static and dynamic MOS memory MOS memory. (2) the surface magnetic memory using magnetic materials made of the surface magnetic memory called memory, or magnetic memory. It includes disk memory, tape memory. Characteristics: size, degree of automation, low production, slow access, but the storage capacity is much greater than the semiconductor memory and not lost. (3) laser memory information stored in the form of scratch disk, the disk with a laser beam through the different reflectivity of the disk to read out information. CDROM can be divided into readonly type optical disk (CDROM), a writeonly type optical disk (WORM) and magnetooptical disk (MOD) in three. 2. Classification according to access (1) random access memory (RAM): If the memory contents of any memory cell can be random access, and memory cell access time and physical location has nothing to do, then this memory is called Random Access Memory (RAM). RAM is mainly used to store a variety of input / output procedures, data, puting intermediate results and storing the information exchange with the outside world and to do with the stack. Mainly act as a random access memory cache and main memory. (2) serial access memory (SAS): If the memory can only be accessed by some kind of order, that is, memory cell access time and physical location, such as the serial access memory storage. Memory can be divided into sequential serial access memory (SAM) and directaccess memory (DAM). Sequential access memory is fully serial access memory, such as tape, and information to the order of the storage medium from the beginning of the beginning of write (or read)。s internal memory. Disk storage prices are cheaper, can do a lot of capacity, but slower access, so access for less, and the need to store a large number of procedures, the raw data (number of programs and data is not to participate in puting the time being) and the results of the external memory. Computer in the implementation of a task, only the relevant procedures and raw data transferred from the disk on a smaller memory capacity, CPU and memory through highspeed data processing, and then the final result will be rewritten into the disk through the memory. This configuration affordable, integrated access speed is faster. To address highspeed CPU and a relatively slow speed of main memory of the contradictions, the cache may also be used. It is fast, the prices higher static semiconductor memory, or even to do together with the microprocessor to store the current most frequently used instructions and data. When the CPU reads instructions from memory and data, will also visit the cache and main memory. If the content required in the cache, you can immediately access。 Byte addressing: byte of memory cells by addressing。 Memory cell: a memory storing a number of characters to form a memory storage unit。[6] 嚴(yán)蔚敏 吳偉民。 最后我還要再次深深地感謝趙為松老師、各位小組成員，正是基于趙老師的悉心指點(diǎn)和大家的全心的幫助，我才能比較順利地完成畢業(yè)設(shè)計(jì)。我們的指導(dǎo)老師：趙為松老師并沒(méi)有指責(zé)，而是給予我們鼓勵(lì)和很多寶貴的建議，并且悉心引導(dǎo)，給予我們一個(gè)比較清晰的設(shè)計(jì)思路。在四年的學(xué)習(xí)期間，曾得到很多班級(jí)同學(xué)的關(guān)心和幫助，在此表示深深的感謝。趙老師淵博的專(zhuān)業(yè)知識(shí)，嚴(yán)謹(jǐn)?shù)闹螌W(xué)態(tài)度，精益求精的工作作風(fēng)，誨人不倦的高尚師德，嚴(yán)以律己、寬以待人的崇高風(fēng)范，樸實(shí)無(wú)華、平易近人的人格魅力對(duì)我影響深遠(yuǎn)?；谶@樣的思路，我們共同完成了快速檢測(cè)甲醛裝置的基本設(shè)計(jì)。軟件與硬件相結(jié)合的演示的大體流程是：主頁(yè)面顯示4個(gè)子菜單功能按鍵的4個(gè)控制進(jìn)入子菜單有確認(rèn)和取消按確認(rèn)實(shí)現(xiàn)相應(yīng)功能（按取消則返回）。根據(jù)設(shè)計(jì)前對(duì)該系統(tǒng)所要實(shí)現(xiàn)功能的要求，綜合考慮慮我們采用AT89C52單片機(jī)為控制核心。具有民用價(jià)值的快速檢測(cè)甲醛裝置的研制受到了人們的高度重視。⑵時(shí)鐘模塊操作流程圖見(jiàn)下圖： 保護(hù)寄存器操作初始化向DS讀取字節(jié)數(shù)據(jù)結(jié)束開(kāi)始向DS寫(xiě)入字節(jié)數(shù)據(jù) 圖 時(shí)鐘模塊操作流程圖⑴LCD模塊在本系統(tǒng)中主要起著開(kāi)界面漢字顯示，以及各控制效果的顯示。功能子函數(shù)的調(diào)用。我們根據(jù)硬件設(shè)計(jì)的主電路圖，按照模塊化設(shè)計(jì)思路設(shè)計(jì)系統(tǒng)的軟件部分。（說(shuō)明：系統(tǒng)硬件設(shè)計(jì)的電路原理圖附在論文的附錄里面。包括：標(biāo)題欄、主菜單、標(biāo)準(zhǔn)工具欄、繪圖工具欄、狀態(tài)欄、對(duì)象選擇按鈕、預(yù)覽對(duì)象方位控制按鈕、仿真進(jìn)程控制按鈕、預(yù)覽窗口、對(duì)象選擇器窗口、圖形編輯窗口?？傊?，該軟件是一款集單片機(jī)和SPICE分析于一身的仿真軟件，功能極其強(qiáng)大。目前支持的單片機(jī)類(lèi)型有：68000系列、8051系列、AVR系列、PIC12系列、PIC16系列、PIC18系列、Z80系列、HC11系列以及各種外圍芯片。然后把提取的點(diǎn)陣碼放入編寫(xiě)的LCD軟件程序里 硬件仿真環(huán)境介紹Proteus ISIS是英國(guó)Labcenter公司開(kāi)發(fā)的電路分析與實(shí)物仿真軟件。 ⑵ 字符顯示：字符顯示比較復(fù)雜，一個(gè)字符由16x8點(diǎn)陣組成，即要找到和顯示屏是某幾個(gè)位置對(duì)應(yīng)的RAM區(qū)的字節(jié)，再使不同的位置為‘1’其他的為‘0’；為‘1’的點(diǎn)亮，為‘0’的不亮，這樣就顯示出一個(gè)字符。3. LCD按其顯示方式通?？梢苑譃閿嗍健Ⅻc(diǎn)字符式、點(diǎn)陣式等。因此，液晶顯示器畫(huà)質(zhì)高且不會(huì)閃爍。即將液晶顯示模塊的數(shù)據(jù)線與單片機(jī)的Pl口連接作為數(shù)據(jù)總線，另外三根時(shí)序控制信號(hào)線通常利用單片機(jī)的P3口中未被使用的I／O口來(lái)控制。1．AMPIRE128X64液晶模塊引腳說(shuō)明AMPIRE128X64液晶共有22個(gè)引腳，其引腳說(shuō)明如表43所示： 表43 液晶引腳說(shuō)明圖管腳名稱(chēng)管 腳 定 義/CSA片選1/CSB片選2VSS數(shù)字地VDD邏輯電源+5VV0對(duì)比度調(diào)節(jié)R/S指令數(shù)據(jù)通道R/W讀寫(xiě)選擇E使能選擇DB0DB7數(shù)據(jù)線CS1片選1CS2片選2/RES復(fù)位信號(hào)VEE液晶驅(qū)動(dòng)電源LED+LED背光正電源LEDLED接地端 表35AMPIRE128X64液晶顯示模塊與計(jì)算機(jī)的接口電路有兩種方式。顯示器最好能夠顯示數(shù)據(jù)、圖形。數(shù)據(jù)輸出是在輸出命令字的8個(gè)SCLK周期之后，在接下來(lái)的8個(gè)SCLK周期中的每個(gè)脈沖的下降沿輸出數(shù)據(jù)，數(shù)據(jù)從0位開(kāi)始。⑷ 日歷、時(shí)鐘寄存器與控制字對(duì)照表、日歷、時(shí)鐘寄存器命令字、取值范圍以及各位內(nèi)容對(duì)照表。其工作時(shí)功耗很低，廣泛應(yīng)用于電話，傳真，便攜式儀器等產(chǎn)品領(lǐng)域。對(duì)時(shí)鐘芯片的要求首先是低功耗，其次是編程簡(jiǎn)單，縮短程序開(kāi)發(fā)時(shí)間，實(shí)際上也就縮短了系統(tǒng)用于實(shí)際生產(chǎn)所用的開(kāi)發(fā)周期以及成本，在本系統(tǒng)，我們選