外文翻譯--存儲器的工作原理

1、<p>　　The work principle of the Memory</p><p>　　The structure of the Memory</p><p>　　The Memory is used to deposit the data. It is to make use of high and low even electricity to deposit th

2、e data, and that is to say, its depositing data is an electricity even and high and low, not the 1234 such as arithmetic figure, then, our riddle undone. So computer is not mysterious too.</p><p>　　A Memory

3、looks like some small drawers, there are eight small blanks in a small drawer, every small blank is used to deposit the " electric charge", the electric charge spreads to come in or release passing the electric

4、 wire that connect with each other, as to the electric charge how to place in the small blank, we need not worried. You can think the electric wire as water pipe. The electric charge in the blank is water. That is easy t

5、o comprehend. The small drawer in saving each one in the mach</p><p>　　We can start depositing the data. If you want to put into a figure 12, that is 00001100, we as long as save No.2 and No.3 small blank in

6、 full electric charge, but other small electric charge in the blank to release. But the problem comes out, Memory contain a lot of units, the line is to parallel. When you put the electric into a blank, you will put the

7、electric charge into all units, and when you release the electric charge, you will put all electric charge in every unit. So how many units the </p><p>　　The Memory translates the code</p><p>　　

8、How we come to control the every unit controlling line? A control for returning remarkably, each unit dollar line leads the outside of the integrated circuit not line? Affair can don't be so simple, one 27512 have 65

9、536 units in Memory, have each line the derivation to, this integrated circuit must more than 60,000 feet? Not line, how do? Wanting the viewpoint reduces the linear quantity.</p><p>　　We have a kind of meth

10、od to call this as to translate the code, the simple introduction is once: Can a line represent 2 kinds of appearances, can 2 lines represent 4 kinds of appearances, can 3 lines represent how many kinds, 256 kinds of app

11、earances need again how many lines represent? 8 kinds? 8 lines? So we need 16 lines to represent 65536 kinds of appearances.</p><p>　　The Memory’s enable chip and the concept of the bus</p><p>　

12、　To this, translate the problem of the code resolved, let us come again to pay attention to another problem. Sending into eight lines of each unit is to use from where of? It is from the calculation on board to connect t

13、o come over, generally, these eight lines besides connecting the Memory, still connect other machine piece, Like this problem come out, these eight lines is not a Memory and a computer appropriatly, if always a certain u

14、nit connecting here eight on-line, not well, for example this</p><p>　　From the introduction above we have seen, the eight lines used to deliver the data and are not special-used, but a lot of components are

15、 public-used. So we call it as the data total line, by name BUS in English in total line, total namely bus way。Who can walk. And 16 addresses line is to be connected together, call it as the address total line.</p>

16、<p>　　The semi-conductor Memory’s classification</p><p>　　According to its function, the Memory can be divided into read and read random Memory two major type. So-called a contents for reading, from t

17、he typeface comprehension is can only with from inside reading, can't writing into, it similarly in our book, hair arriving our returning after, our can reading inside, must not change the contents on the book as one

18、's pleases. An English for reading saving machine abbreviation is ROM (READ ONLY MEMORY).</p><p>　　Memory so-called random access, can rewrite at any time namely, the data that also can read the inside,

19、it is similar in our blackboard, I can write at any time the thing goes up, also can wipe to rewrite with the blackboard. Saving the English abbreviation of the machine as with the machine RAM (READ RANDOM MEMORY) these

20、two kinds of saving machines English abbreviation must keep in mind.</p><p>　　Attention: the so-called read to point with random access all the time of normal work circumstance descending and speech, and als

21、o is at using the this piece of saving the machine, not time to point to make this piece of chip. Otherwise, read the saving data in the machine to how come of? In fact, this truth is very easy to comprehend, the book ge

22、ts hold of our hand is to can't change, can be it still white paper in— in— in original material of time, was printed by printing press up certainly.</p><p>　　5. Explain the other a few and familiar con

23、cepts by the way</p><p>　　PROM, call it as the programmable ROM. This is like our exercise book, buy of the time is blank, can write the thing go up, can once write up, wiped to do not drop, so it can use to

24、 write once, if write mistake, submit an expense account.</p><p>　　EPROM, call it as that the ultraviolet ray wipes the programmable that divided by reads the saving machine. It inside of after contents writ

25、e go up, if feel dissatisfied, can rewrite after throwing away with a kind of special method, this is to uses the ultraviolet ray irradiation, ultraviolet ray elephant" the word of works properly", can throw aw

26、ay the word, then rewrite. Certainly the number of times are many, and also ineffective light, so a number of times for can wipe divided by is also a </p><p>　　FLASH ROM, call it as the thing that save the m

27、achine soon, it is similar with the EPROM, writing up can also wipe off to rewrite, but it want the convenience the some, do not need the light shone on, as long as use the science of electricity method and then can wipe

28、 to divided by, so the convenience is many, and the life is too very long. (Several ten thousand arrive several do not wait 100,000 times)</p><p>　　Emphasize again, the things here write are all not at the n

29、ormal work term. Whether it is a PROM, EPROM or FLASH ROM, their writing all has special limits. Generally, we use a kind of called as" programmable controller" to do this work. Once packed to the work position

30、, you won’t rewrite literally.</p><p>　　6. In addition, to describe the Single-chip microcomputer 8051’s configuration </p><p>　　8051 films have ROM (Procedure memory, only time) and Ram (dat

31、a memory, could write readable) categories, which are separate memory address space, and general computer memory allocation method is the same. Usually only one general computer address space, ROM and Ram that can be arb

32、itrarily placed in the context of a different address space, ROM and Ram addresses in a league with different addresses in the distribution space. CPU visits the ROM, a correspondence address only Memory module can be &l

33、t;/p><p>　　Interior and foreign films uniform procedures for site 0000H--FFFFH the 64KB ROM address space (16 bit space in the address). </p><p>　　64KB of data memory address space film, the addr

34、ess from 0000H--FFFFH series site (with 16 addresses) for the site. </p><p>　　256KB data memory address space (with eight address lines). </p><p>　　The three overlapping memory space address i

35、s how to distinguish between three different logical space? 8051 instructions different data transmission systems design directive Key: CPU visit of films, foreign films directed by MOVC ROM, RAM, visit film directed by

36、MOVX visit films of Ram using MOV instructions. </p><p>　　8051 memory address space into procedures memory (64KB) and data memory (64KB). Procedure of the Memory is good procedure and form constants. Proce

37、dures ROM through 16 procedures laid find the address, its ability to 64KB. In order to make this arbitrary jump 64KB address space, and also can not make the transfer process from the process memory space to data memory

38、 space. </p><p>　　Data memory is used to store intermediate results of operation、 data pending buffer and mark bits and so on. </p><p>　　Data memory space is divided into interior and exterior f

39、ilms, Viz. interior and exterior RAM. </p><p>　　8051 exterior data memory space is 64KB, from 0000H to FFFFH; interior memory space is 256 Bytes, from 0000H to 00FFH address.</p><p><b>　

40、　存儲器的工作原理</b></p><p><b>　　1. 存儲器構(gòu)造</b></p><p>　　存儲器就是用來存放數(shù)據(jù)的地方。它是利用電平的高低來存放數(shù)據(jù)的，也就是說，它存放的實際上是電平的高、低，而不是我們所習(xí)慣認(rèn)為的數(shù)字1234，這樣，我們的一個謎團(tuán)就解開了，計算機也沒什么神秘的吧。</p><p>　　一個存儲器就像一個

41、個的小抽屜，一個小抽屜里有八個小格子，每個小格子是用來存放“電荷”的，電荷通過與它相連的電線傳進(jìn)來或釋放掉，至于電荷在小格子里是怎樣存放的，就不用我們操心了，你可以把電線想象成水管，小格子里的電荷就像是水，那就好理解了。存儲器中的每個小抽屜就是一個放數(shù)據(jù)的地方，我們稱之為一個“單元”。有了這么一個構(gòu)造，我們就可以開始存放數(shù)據(jù)了，想要放進(jìn)一個數(shù)據(jù)12，也就是00001100，我們只要把第二號和第三號小格子里存滿電荷，而其它小格子里的電荷給

42、放掉就行了。可是問題出來了，一個存儲器有好多單元，線是并聯(lián)的，在放入電荷的時候，會將電荷放入所有的單元中，而釋放電荷的時候，會把每個單元中的電荷都放掉，這樣的話，不管存儲器有多少個單元，都只能放同一個數(shù)，這當(dāng)然不是我們所希望的，因此，要在結(jié)構(gòu)上稍作變化，在每個單元上有個控制線，想要把數(shù)據(jù)放進(jìn)哪個單元，就給一個信號單元的控制線，這個控制線就把開關(guān)打開，這樣電荷就可以自由流動了，而其它單元控制線上沒有信號，所以開關(guān)不打開，不會受到影響，這樣

43、，只要控制不同單元的控制線，就可以向各單元寫入不同的數(shù)據(jù)，同樣，如果要從某個單元中取數(shù)據(jù)，也只要打開相</p><p><b>　　2. 存儲器譯碼</b></p><p>　　那么，我們怎樣來控制各個單元的控制線呢？這個還不簡單，把每個單元的控制線都引到集成電路的外面不就行了嗎？事情可沒那么簡單，一片27512存儲器中有65536個單元，把每根線都引出來，這個集成電

44、路就得有6萬多個腳？不行，那怎么辦？要想法減少線的數(shù)量。</p><p>　　我們有一種方法稱之為譯碼，簡單介紹一下：一根線可以代表2種狀態(tài)，2根線可以代表4種狀態(tài)，3根線可以代表幾種，256種狀態(tài)又需要幾根線代表？8種，8根線，所以65536種狀態(tài)我們只需要16根線就可以代表了。</p><p>　　3. 存儲器的選片及總線的概念</p><p>　　至此，譯碼的

45、問題解決了，讓我們再來關(guān)注另外一個問題。送入每個單元的八根線是從什么地方來的呢？它就是從計算機上接過來的，一般地，這八根線除了接一個存儲器之外，還要接其它的器件。這樣問題就出來了，這八根線既然不是存儲器和計算機之間專用的，如果總是將某個單元接在這八根線上，就不好了，比如這個存儲器單元中的數(shù)值是0FFH，另一個存儲器的單元是00H，那么這根線到底是處于高電平，還是低電平呢？豈非要打架看誰歷害了？所以我們要讓它們分離。辦法當(dāng)然很簡單，當(dāng)外面

46、的線接到集成電路的引腳后，不直接接到各單元去，中間再加一組開關(guān)就行了。平時我們讓開關(guān)打開著，如果確實是要向這個存儲器中寫入數(shù)據(jù)，或要從存儲器中讀出數(shù)據(jù)，再讓開關(guān)接通就行了。這組開關(guān)由三根引線選擇：讀控制端、寫控制端和片選端。要將數(shù)據(jù)寫入片中，先選中該片，然后發(fā)出寫信號，開關(guān)就合上了，并將傳過來的數(shù)據(jù)（電荷）寫入片中。如果要讀，先選中該片，然后發(fā)出讀信號，開關(guān)合上，數(shù)據(jù)就被送出去了。注意讀和寫信號同時還接入到另一個存儲器，但是由于片選端不

47、同，所以雖有讀或?qū)懶盘?，但沒有片選信號，所以另一個存儲器不會“誤會”而開門，造成沖突。那么會不會同時選中兩個</p><p>　　從上面的介紹中我們已經(jīng)看到，用來傳遞數(shù)據(jù)的八根線并不是專用的，而是很多器件大家共用的，所以我們稱之為數(shù)據(jù)總線，總線英文名為BUS，總線即公交車道，誰都可以走。而十六根地址線也是連在一起的，稱之為地址總線。</p><p>　　4. 半導(dǎo)體存儲器的分類 </

48、p><p>　　按功能可以分為只讀和隨機存取存儲器兩大類。所謂只讀，從字面上理解就是只可以從里面讀，不能寫進(jìn)去，它類似于書本，發(fā)到手中后，通常只能讀里面的內(nèi)容，不可以隨意更改書本上的內(nèi)容。只讀存儲器的英文縮寫為ROM。</p><p>　　所謂隨機存取存儲器，即隨時可以改寫，也可以讀出里面的數(shù)據(jù)，它類似于黑板，可以隨時寫東西上去，也可以用黑板擦擦掉重寫。隨機存儲器的英文縮寫為RAM（READ

49、RANDOM MEMORY）這兩種存儲器的英文縮寫一定要記牢。</p><p>　　注意：所謂的只讀和隨機存取都是指在正常工作情況下而言，也就是在使用這塊存儲器的時候，而不是指制造這塊芯片的時候。否則，只讀存儲器中的數(shù)據(jù)是怎么來的呢？其實這個道理也很好理解，書本拿到手里是不能改了，可當(dāng)它還是原材料——白紙的時候，當(dāng)然可以由印刷廠印上去了。</p><p>　　5. 順便解釋一下其它幾個常見

50、的概念</p><p>　　PROM，稱之為可編程存儲器。這就像練習(xí)本，買來的時候是空白的，可以寫東西上去，可一旦寫上去，就擦不掉了，所以它只能寫一次，如果寫錯，就報銷了。</p><p>　　EPROM，稱之為紫外線擦除的可編程只讀存儲器。它里面的內(nèi)容寫上去之后，如果覺得不滿意，可以用一種特殊的方法去掉后重寫，這就是用紫外線照射，紫外線就像“消字靈”，可以把字去掉，然后再重寫。當(dāng)然消的次

51、數(shù)多了，也就不靈光了，所以這種芯片可以擦除的次數(shù)也是有限的。</p><p>　　FLASH ROM，稱之為閃速存儲器，它和EPROM類似，寫上去的東西也可以擦掉重寫，但它要方便一些，不需要光照了，只要用電化學(xué)方法就可以擦除，所以就方便了許多，而且壽命也很長（幾萬到幾十萬次不等）。</p><p>　　再次強調(diào)，這里所有的寫都不是指在正常工作條件下。不管是PROM、EPROM還是FLASH

52、 ROM，它們的寫都要有特殊的條件，一般用一種稱之為“編程器”的設(shè)備來做這項工作，一旦把它裝到它的工作位置上，就不能隨便改寫了。</p><p>　　6. 另外介紹一下8051單片機的配置</p><p>　　8051片內(nèi)有ROM（程序存儲器，只能讀）和RAM（數(shù)據(jù)存儲器，可讀可寫）兩類，它們有各自獨立的存儲地址空間，與一般微機的存儲器配置方式很不相同。一般微機通常只有一個地址空間，ROM

53、和RAM可以隨意安排在這一地址范圍內(nèi)不同的空間，即ROM和RAM的地址同在一個隊列里分配不同的地址空間。CPU訪問存儲器時，一個地址對應(yīng)唯一的存儲器單元，可以是ROM，也可以是RAM，并用同類訪問指令。</p><p>　　8051的存儲器在物理結(jié)構(gòu)上分為程序存儲器空間和數(shù)據(jù)存儲器空間，從用戶使用的角度看，8051存儲器地址空間分為三類：</p><p>　　(1)片內(nèi)外統(tǒng)一編址0000H

54、——FFFFH的64KB程序存儲器地址空間（用16位地址）；</p><p>　　(2)64KB片外數(shù)據(jù)存儲器地址空間，地址也從0000H——FFFFH編址（用16位地址）；</p><p>　　(3)256KB數(shù)據(jù)存儲器地址空間（用8位地址）。</p><p>　　上述三個存儲器空間地址是重疊的，如何區(qū)別這三個不同的邏輯空間呢？8051的指令系統(tǒng)設(shè)計了不同的數(shù)據(jù)傳

55、送指令符號：CPU訪問片內(nèi)、片外ROM指令用MOVC，訪問片外RAM指令用MOVX，訪問片內(nèi)RAM指令用MOV。</p><p>　　程序存儲器用于存放編好的程序和表格常數(shù)。程序存儲器通過16位程序計數(shù)器尋址，尋址能力為64KB。這使得指令能在64KB地址空間任意跳轉(zhuǎn)，但不能使程序從程序存儲器空間轉(zhuǎn)移到數(shù)據(jù)存儲器空間。</p><p>　　數(shù)據(jù)存儲器RAM用于存放運算的中間結(jié)果、數(shù)據(jù)暫存和