《微機原理與接口技術(shù)鍵盤LED顯示【課程設計報告】》由會員分享，可在線閱讀，更多相關(guān)《微機原理與接口技術(shù)鍵盤LED顯示【課程設計報告】（25頁珍藏版）》請在裝配圖網(wǎng)上搜索。

1、重慶大學課 程 設 計 報 告課程名稱： 微機原理與接口技術(shù) 設計題目： 鍵盤LED顯示 院 系：電氣信息學院 班 級： 2007級 設計時間：2009年12月 第一章 概述21.1學習目的21.2 計算機的應用21.3學習計算機的意義31.4課程設計目的3第二章 總體方案設計42.1 設計注意問題42.2 總體思路4第三章 硬件設計53.1 8255工作原理53.2 鍵盤工作原理73.3 鍵特征值的形成83.4段值的形成83.5 8255接線圖9第四章 軟件設計104.1 8255初始化104.2 鍵盤掃描的處理方法104.2.1. 判斷是否有鍵被按下的方法104.2.2. 判斷是否有鍵被按

2、下的源程序114.2.3 防抖動114.2.4.防抖動的延時子程序124.3 程序核心部分124.3.1 逐行掃描124.3.2逐行掃描的源程序12第五章 源程序代碼135.1 根據(jù)整體思路以及軟件設計得到的代碼135.2 以上代碼存在問題分析16第六章 難點分析16第七章 體會 感慨 建議19第八章 參考文獻20 第一章 概述1.1學習目的“微機原理與接口技術(shù)”是電氣工程及其自動化專業(yè)的一門重要的專業(yè)基礎課程。我們通過該門課的學習，知道了微機的工作原理，微型計算機的基本結(jié)構(gòu)，接口技術(shù)及匯編語言程序設計，為后續(xù)的課程的學習和今后的工作打下堅實的基礎。通過實驗可以培養(yǎng)學生利用計算機技術(shù)和編程手段

3、分析，解決專業(yè)領(lǐng)域的各種問題的能力和意識，并進一步感受微機發(fā)展的微機發(fā)展的新技術(shù)和新方法。1.2 計算機的應用目前計算機的應用已經(jīng)遍布各個行業(yè)，如科學計算、數(shù)據(jù)處理、過程控制、人工智能、網(wǎng)絡應用等?？茖W和工程計算：科學和工程計算的特點是計算量大，而邏輯關(guān)系相對簡單，它是計算機重要應用領(lǐng)域之一。數(shù)據(jù)和信息處理：數(shù)據(jù)處理是指對數(shù)據(jù)的收集、存儲、加工、分析和傳送的全過程。這些數(shù)據(jù)處理應用的特點是數(shù)據(jù)量很大，但計算相對簡單。多媒體技術(shù)的發(fā)展，為數(shù)據(jù)處理增加了新鮮內(nèi)容，都涉及更廣泛的數(shù)據(jù)類型，這些數(shù)據(jù)處理過程不僅數(shù)據(jù)量大，而且還會帶來大量的運算和復雜的運算過程。過程控制：過程控制是生產(chǎn)自動化的重要技術(shù)內(nèi)

4、容和手段，它是由計算機對所采集到的數(shù)據(jù)按一定方法經(jīng)過計算，然后輸出到指定執(zhí)行機構(gòu)去控制生產(chǎn)的過程。人工智能：人們把計算機模擬人腦力勞動的過程成為人工智能。人工智能是利用計算機來模擬人的思維過程，并利用計算機程序來實現(xiàn)這些過程。 1.3學習計算機的意義電子計算機是一種能自動高速地進行大量運算的電子機器。電子計算機的出現(xiàn)和發(fā)展，是科學技術(shù)和生產(chǎn)力的卓越成就之一，反過來，它也極大地促進了科學技術(shù)和生產(chǎn)力的發(fā)展。微型計算機的發(fā)展前景是不可估量的。微型計算機功能強，體積小，使用方便，可靠性高，價格低廉，因而應用范圍非常廣泛，航天工業(yè)，交通運輸，醫(yī)藥衛(wèi)生甚至家庭生活及教學儀器等方面都廣泛地使用了微型計算機

5、。毫無疑問，今后微型計算機在人類社會和日常生活中的影響將會越來越大。感受接口的重要作用，學會微機與接口的綜合應用。掌握接口的編程技術(shù)。1.4課程設計目的 1.掌握 8255的使用和編程方法。 2.通過8255設計鍵盤掃描及它們的輸入輸出方式和它們的控制字。綜合運用本學期所學的關(guān)于匯編的知識，在實驗中進一步熟悉本學期所學的課程并結(jié)合實際生活，掌握匯編的應用。 3.注重鍵盤掃描的方法設計以及解決問題的思路。 4.了解任何微機應用開發(fā)工作都離不開接口的技術(shù)、選用及連接。微機應用系統(tǒng)需要設計的硬件是一些接口電路，所要編寫的軟件是控制這些接口電路按要求工作的驅(qū)動程序。重點講述可編程并行接口芯片8255A

6、、內(nèi)部結(jié)構(gòu)、工作方式、初始化編程及其應用實例。第二章 總體方案設計2.1 設計注意問題 在唐都實驗箱上實現(xiàn)鍵盤掃描并顯示在LED上，比如當按下6時，LED會顯示6的字樣?？傮w設計方案如下： 1.實現(xiàn)鍵盤的掃描（鍵號與鍵值的對應）。 2.防抖動措施。 3.防重鍵的措施。2.2 總體思路 本次試驗報告的整體思路如下：1. 行開放，找到列值并保存；2. 逐行掃描，找到行值并保存；3. 行值和列值組合成鍵特征值；4. 根據(jù)鍵特征值找到鍵號；5. 根據(jù)鍵號查表得段碼；6. 送出相應位碼。鍵盤掃描邏輯性很強，步步相扣。思路顯得尤其重要。第三章 硬件設計3.1 8255工作原理并行接口是以數(shù)據(jù)的字節(jié)為單位與

7、I/O設備或被控制對象之間傳遞信息。CPU和接口之間的數(shù)據(jù)傳送總是并行的，即可以同時傳遞8位、16位或32位等。8255 A可編程外圍接口芯片是Intel 公司生產(chǎn)的通用并行I/O 接口芯片，它具有A、B、C 三個并行接口，用+5V 單電源供電，能以下三種方式下工作：方式0：基 輸入/輸出方式方式1：選通輸入/輸出方式方式2：雙向選通工作方式8255A的內(nèi)部結(jié)構(gòu)及引腳如圖3.1 所示，8255 工作方式控制字和 C口按位 置位/復位控制字格式如圖3.2所示。 雙向選通工作方式。8255的內(nèi)部結(jié)構(gòu)及引腳如圖3.1所示，8255工作方式控制字和C口按位置位/復位控制字如圖3.3所示圖3.1 825

8、5的內(nèi)部結(jié)構(gòu)及引腳圖3.2 8255工作方式控制字和C口按位置位/復位控制字3.2 鍵盤工作原理 唐都實驗箱提供的是4*4的小鍵盤，如下圖所示， 列為高電平。并且位選口與行控口共用端口。鍵盤原理圖3.2：FE7dCbA9876543210列0列1列2列3 0 0+5 圖3.2 鍵盤原理圖鍵盤工作原理闡述： 每一個鍵跨接在行、列線之間； 在無按鍵時，列線固定為高電平；列控制口用于讀入列線狀態(tài)，即列值。 行線電平受控于“行控制口”，行控口輸出的信號稱為行值 某鍵未按下，該鍵關(guān)聯(lián)的行、列線不通；按下，則把行線的電平引入列線。設置行線為低電平，則把行線的低電平引入列線。3.3 鍵特征值的形成根據(jù)鍵盤的

9、工作原理可以得到如下鍵特征值表3.4： 鍵值列值行值鍵特征值鍵值列值行值鍵特征值00111B1110B7EH10111B1101B7DH20111B1011B7BH30111B0111B77H41011B1110BBEH51011B1101BBDH61011B1011BBBH71011B0111BB7H81101B1110BDEH91101B1101BDDHA1101B1011BDBHb1101B0111BD7HC1110B1110BEEHd1110B1101BEDHE1110B1011BEBHF1110B0111BE7H .3鍵特征值表3.4段值的形成 DpgfedcbaD7D6D5D4D3

10、D2D1D0000111111 3FH100000110 06H2010110115BH301001111 4FH 401100110 66H501101101 6DH601111101 7DH700000111 07H801111111 7FH901101111 6FHA01110111 77Hb01111100 7CHC00111001 39H d01011110 5EHE01111001 79HF0111000171H顯示段值見表3.5表3.4 段碼表3.5 8255接線圖 PB PA0 PA1 PA2 PA3 PC3 PC2PC1 PC0 LED6 LED5 LED4 LED3 LED

11、2 LED1 列控位控行控+5V 圖3.5 8255接線圖3.6 寄存器地址選取 根據(jù)唐都實驗儀器提供的手冊，選取IOY1作為8255芯片的片選端口，A1 A0為片內(nèi)譯碼。即：PA口地址： 0640HPB口地址： 0642HPC口地址： 0644PD(控制口) 地址： 0646H第四章 軟件設計4.1 8255初始化以PC為列控口；以PA低4位為行控口；列口為輸入，行口輸出；顯示以PB為段選口；PB口輸出；PA低6位為位選。根據(jù)3.1與3.2 得出8255芯片的控制字為：10001001B，即：89H。4.2 鍵盤掃描的處理方法4.2.1. 判斷是否有鍵被按下的方法 行開放：使所有行線輸出低電

12、平，從列控口讀入列狀態(tài)（列值）即： 通過行控口，輸出全0 。4條行線均為低電平。如果沒有鍵按下，則行線低電平不會引入到列線，從列控口讀入的必為全1；只要有一個鍵按下，如F鍵，則行1的低電平引入列3，從列控口讀入的列值為1110，非全1，由此得出判斷是否有鍵按下的條件： 讀入的列值為全1，無按鍵；非全1，必有按鍵！判斷是否有鍵被按下的流程：1. 讓行線輸出全為0；2. 讀列的值；3. 判斷列值是否全為0；4. 若不全為0，則說明有按鍵按下；5. 全為0，則說明沒有按鍵按下，繼續(xù)等待輸入。 4.2.2. 判斷是否有鍵被按下的源程序 MOV DX,0640H MOV AL,00H OUT DX,AL

13、JXSR: MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH JE JXSR對源程序的解釋：程序中只需要C口低四位，所以用“AND AL,0FH”對低4位保存4.2.3 防抖動防抖動措施對按鍵來說是必需的，可以讓微機準確輸入，在課程設計中，利用延時子程序來實現(xiàn)防抖動。4.2.4.防抖動的延時子程序 DELAY PROC NEAR ;延時子程序 MOV CX,0F000HDLP: LOOP DLP RETDELAY ENDP4.3 程序核心部分4.3.1 逐行掃描 問題：怎么判斷按鍵說在行的位置？ 查閱資料，判斷按鍵所在行的位置用逐行掃描的方法。 逐行掃描：

14、使行線輸出逐一為低電平，從列控口讀入列狀態(tài)（列值）。 此時如果列值讀入為全1，則按鍵不在本行；非全1，在本行。 判斷是否有鍵被按下的流程：1. 使第0行為0（掃描0行）；2. 讀入列值；3. 判斷列值是否全為04. 若列值全為0，則說明按鍵不在本行；5. 列值移位，再次讀入列值，進行判斷。4.3.2逐行掃描的源程序 LOP1:MOV DX,0640H OUT DX,AL MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH JNE ZJSC ROL AH,1 MOV AL,AH JMP LOP1逐行掃描的源程序的解釋：ROL AH,1，行值移位后繼續(xù)掃描。 第

15、五章 源程序代碼5.1 根據(jù)整體思路以及軟件設計得到的代碼 DATA SEGMENT DZTABLE DB 3FH,06H,5BH,4FH,66DB 6DH,7DH,07H,7FH,6FH DB 77H,7CH,39H,5EH,79H,71H JZTABLE DB 7EH,7DH,7BH,77H DB 0BEH,0BDH,0BBH,0B7H DB 0DEH,0DDH,0DBH,0D7H DB 0EEH,0EDH,0EBH,0E7HDATA ENDSCODE SEGMENT ASSUME CS:CODE,DS:DATA START: MOV AX,DATA MOV DS,AX MOV DX,06

16、46H MOV AL,89H OUT DX,AL ；初始化 T1: MOV DX,0640H ；行開放 MOV AL,00H OUT DX,AL JXSR: MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH JE JXSR CALL DELAY ；防抖動 MOV BL,AL ；保存列值 MOV AL,0FEH ；逐行掃描 MOV AH,AL LOP1:MOV DX,0640H OUT DX,AL MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH JNE ZJSC ROL AH,1 MOV AL,AH JMP LOP1

17、ZJSC:SHL BL,4 AND AH,0FH OR BL,AH ；形成鍵特征值 LEA SI,JZTABLE MOV CL,0 LOP3:CMP BL,SI JE LOP2 INC CL INC SI JMP LOP3 LOP2:MOV DX,0640H MOV AL,00H OUT DX,AL LOP4: MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH JNE LOP4 CALL DELAY LEA DI,DZTABLE MOV BX,DI MOV AL,CL XLAT MOV DX,0642H OUT DX,AL MOV DX,0640H MOV

18、 AL,00H OUT DX,AL MOV AH,4CH INT 21H DELAY PROC NEAR ;延時子程序 MOV CX,0F000HDLP: LOOP DLP RETDELAY ENDPCODE ENDS5.2 以上代碼存在問題分析 以上源代碼在理論上已經(jīng)準確了，但是任然不能調(diào)試成功，經(jīng)過細心檢查，發(fā)現(xiàn)源程序中的延時子程序出現(xiàn)問題。DELAY PROC NEAR ;延時子程序 MOV CX,0F000HDLP: LOOP DLPRETDELAY ENDPCODE ENDS在延時子程序中用了寄存器CX，但是后面程序中還要用CX，沒有保存現(xiàn)場。應該改為：DELAY PROC NEAR

19、 PUSH CX MOV CX,0F000HDLP: LOOP DLP POP CXRETDELAY ENDPCODE ENDS第六章 難點分析本課程設計的難點之一是行掃描的實現(xiàn)。以上工作做完后，已經(jīng)能顯示了，鍵盤掃描問題就基本解決了。但是本課程設計的又一難點怎么實現(xiàn)防重鍵？我想的方法是根據(jù)鍵特征值去判斷：觀察鍵特征值，發(fā)現(xiàn)鍵特征值0的個數(shù)均是偶數(shù)。就利用此條件去判斷，若出現(xiàn)奇數(shù)則是重鍵，具體操做見一下程序 DATA SEGMENT DZTABLE DB 3FH,06H,5BH,4FH,66DB 6DH,7DH,07H,7FH,6FH DB 77H,7CH,39H,5EH,79H,71H JZ

20、TABLE DB 7EH,7DH,7BH,77H DB 0BEH,0BDH,0BBH,0B7H DB 0DEH,0DDH,0DBH,0D7H DB 0EEH,0EDH,0EBH,0E7HDATA ENDSCODE SEGMENT ASSUME CS:CODE,DS:DATA START: MOV AX,DATA MOV DS,AX MOV DX,0646H MOV AL,89H OUT DX,AL ；初始化 T1: MOV DX,0640H ；行開放 MOV AL,00H OUT DX,AL JXSR: MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH J

21、E JXSR CALL DELAY ；防抖動 MOV BL,AL ；保存列值 MOV AL,0FEH ；逐行掃描 MOV AH,AL LOP1:MOV DX,0640H OUT DX,AL MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH JNE ZJSC ROL AH,1 MOV AL,AH JMP LOP1 ZJSC:SHL BL,4 AND AH,0FH OR BL,AH ；形成鍵特征值 JNP AAA ；防重鍵 LEA SI,JZTABLE MOV CL,0 LOP3:CMP BL,SI JE LOP2 INC CL INC SI JMP LOP3

22、 LOP2:MOV DX,0640H MOV AL,00H OUT DX,AL LOP4: MOV DX,0644H IN AL,DX AND AL,0FH CMP AL,0FH JNE LOP4 CALL DELAY LEA DI,DZTABLE MOV BX,DI MOV AL,CL XLAT MOV DX,0642H OUT DX,AL MOV DX,0640H MOV AL,00H OUT DX,ALAAA JMP T1MOV DX,0640H MOV AL,00H OUT DX,AL MOV AH,4CH INT 21H DELAY PROC NEAR ;延時子程序 MOV CX,0

23、F000HDLP: LOOP DLP RETDELAY ENDPCODE ENDS這才是本次課程設計的最終可執(zhí)行程序。 第七章 體會 感慨 建議1、通過這次課程設計，加強了我們動手、思考和解決問題的能力。在整個設計過程中，我們通過這個方案包括設計了鍵盤掃描LED顯示。這個方案使用了8255可編程接口芯片。2、在設計過程中，經(jīng)常會遇到這樣那樣的情況，就是心里想老著這樣的接法可以行得通，但實際接上電路，總是實現(xiàn)不了，因此耗費在這上面的時間用去很多。3. 通過這次課程設計使我懂得了理論與實際相結(jié)合是很重要的，只有理論知識是遠遠不夠的，只有把所學的理論知識與實踐相結(jié)合起來，從理論中得出結(jié)論，才能真正為

24、社會服務，從而提高自己的實際動手能力和獨立思考的能力。在設計的過程中遇到問題，可以說得是困難重重，這畢竟第一次做的，難免會遇到過各種各樣的問題，同時在設計的過程中發(fā)現(xiàn)了自己的不足之處，對以前所學過的知識理解得不夠深刻，掌握得不夠牢固。4.此次課程設計，學到了很多課內(nèi)學不到的東西，比如獨立思考解決問題，出現(xiàn)差錯的隨機應變，和與人合作共同提高，都受益非淺，今后的制作應該更輕松，自己也都能扛的起并高質(zhì)量的完成項目。5.此次課程設計使我真正的掌握了小健盤的掃描方法，讓我知道了解決設計問題的方法。從整個設計流程我知道問題是一步步地解決的。不能懼怕問題，問題的提出就是自我進步，自我升華的關(guān)鍵。6.此次課程

25、設計很好地培養(yǎng)了自己對知識的綜合應用能力。7.短短的兩周轉(zhuǎn)瞬即逝，現(xiàn)在還回味無窮，對課程設計總有意猶未盡的感覺，保留這份感覺繼續(xù)激勵自己前進吧！5 在此，感謝蔡華老師的細心指導，也同樣謝謝其他各組同學的無私幫助！第八章 參考文獻1.80*86微機原理學生指導書2.80*86微機原理教師指導書3.馬春燕主編 微機原理與接口技術(shù) 電子工業(yè)出版社 g an employment tribunal claimEmployment tribunals sort out disagreements between employers and employees.You may need to make a

26、 claim to an employment tribunal if: you dont agree with the disciplinary action your employer has taken against you your employer dismisses you and you think that you have been dismissed unfairly.For more information about dismissal and unfair dismissal, seeDismissal.You can make a claim to an empl

27、oyment tribunal, even if you haventappealedagainst the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any compensation awarded to you as a result of your failure to appeal.Remember that in most cases you must make an application to an

28、employment tribunal within three months of the date when the event you are complaining about happened. If your application is received after this time limit, the tribunal will not usually accept it.If you are worried about how the time limits apply to you, take advice from one of the organisations l

29、isted underFurther help.Employment tribunals are less formal than some other courts, but it is still a legal process and you will need to give evidence under an oath or affirmation.Most people find making a claim to an employment tribunal challenging. If you are thinking about making a claim to an e

30、mployment tribunal, you should get help straight away from one of the organisations listed underFurther help.If you are being represented by a solicitor at the tribunal, they may ask you to sign an agreement where you pay their fee out of your compensation if you win the case. This is known as adama

31、ges-based agreement. In England and Wales, your solicitor cant charge you more than 35% of your compensation if you win the case.If you are thinking about signing up for a damages-based agreement, you should make sure youre clear about the terms of the agreement. It might be best to get advice from

32、an experienced adviser, for example, at a Citizens Advice Bureau. To find your nearest CAB, including those that give advice by e-mail, click onnearest CAB.For more information about making a claim to an employment tribunal, seeEmployment tribunals.The (lack of) air up there Watch mCayman Islands-ba

33、sed Webb, the head of Fifas anti-racism taskforce, is in London for the Football Associations 150th anniversary celebrations and will attend Citys Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Yaya Toure, he told BBC Sport.For me its about

34、how he felt and I would like to speak to him first to find out what his experience was.Uefa hasopened disciplinary proceedings against CSKAfor the racist behaviour of their fans duringCitys 2-1 win.Michel Platini, president of European footballs governing body, has also ordered an immediate investig

35、ation into the referees actions.CSKA said they were surprised and disappointed by Toures complaint. In a statement the Russian side added: We found no racist insults from fans of CSKA.Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life be

36、came the appearance of the same day; May be back in the past, to oneself the paranoid weird belief disillusionment, these days, my mind has been very messy, in my mind constantly. Always feel oneself should go to do something, or write something. Twenty years of life trajectory deeply shallow, sudde

37、nly feel something, do it.一字開頭的年齡已經(jīng)到了尾聲?；蛟S是愧疚于自己似乎把轉(zhuǎn)瞬即逝的很多個不同的日子過成了同一天的樣子；或許是追溯過去，對自己那些近乎偏執(zhí)的怪異信念的醒悟，這些天以來，思緒一直很凌亂，在腦海中不斷糾纏?？傆X得自己自己似乎應該去做點什么，或者寫點什么。二十年的人生軌跡深深淺淺，突然就感覺到有些事情，非做不可了。The end of our life, and can meet many things really do?而窮盡我們的一生，又能遇到多少事情是真正地非做不可？During my childhood, think lucky money an

38、d new clothes are necessary for New Year, but as the advance of the age, will be more and more found that those things are optional; Junior high school, thought to have a crush on just means that the real growth, but over the past three years later, his writing of alumni in peace, suddenly found tha

39、t isnt really grow up, it seems is not so important; Then in high school, think dont want to give vent to out your inner voice can be in the high school children of the feelings in a period, but was eventually infarction when graduation party in the throat, later again stood on the pitch he has swea

40、t profusely, looked at his thrown a basketball hoops, suddenly found himself has already cant remember his appearance.童年時，覺得壓歲錢和新衣服是過年必備，但是隨著年齡的推進，會越來越發(fā)現(xiàn)，那些東西根本就可有可無；初中時，以為要有一場暗戀才意味著真正的成長，但三年過去后，自己心平氣和的寫同學錄的時候，突然就發(fā)現(xiàn)是不是真正的成長了，好像并沒有那么重要了；然后到了高中，覺得非要吐露出自己的心聲才能為高中生涯里的懵懂情愫劃上一個句點，但畢業(yè)晚會的時候最終還是被梗塞在了咽喉，后來再次站

41、在他曾經(jīng)揮汗如雨的球場，看著他投過籃球的球框時，突然間發(fā)現(xiàn)自己已經(jīng)想不起他的容顏。Originally, this world, can produce a chemical reaction to an event, in addition to resolutely, have to do, and time.原來，這個世界上，對某個事件能產(chǎn)生化學反應的，除了非做不可的堅決，還有，時間。A persons time, your ideas are always special to clear. Want, want, line is clear, as if nothing could

42、shake his. Also once seemed to be determined to do something, but more often is he backed out at last. Dislike his cowardice, finally found that there are a lot of love, there are a lot of miss, like shadow really have been doomed. Those who do, just green years oneself give oneself an arm injection

43、, or is a self-righteous spiritual.一個人的時候，自己的想法總是特別地清晰。想要的，不想要的，界限明確，好像沒有什么可以撼動自己。也曾經(jīng)好像已經(jīng)下定了決心去做某件事，但更多的時候是最后又打起了退堂鼓。嫌惡過自己的怯懦，最終卻發(fā)現(xiàn)有很多緣分，有很多錯過，好像冥冥之中真的已經(jīng)注定。那些曾經(jīng)所謂的非做不可，只是青蔥年華里自己給自己注射的一支強心劑，或者說，是自以為是的精神寄托罷了。At the moment, the sky is dark, the air is fresh factor after just rained. Suddenly thought of

44、 blue plaid shirt; Those were broken into various shapes of stationery; From the corner at the beginning of deep friendship; Have declared the end of the encounter that havent start planning. Those years, those days of do, finally, like youth, will end in our life.此刻，天空是陰暗的，空氣里有著剛下過雨之后的清新因子。突然想到那件藍格

45、子襯衫；那些被折成各種各樣形狀的信紙；那段從街角深巷伊始的友誼；還有那場還沒有開始就宣告了終結(jié)的邂逅計劃那些年那些天的非做不可，終于和青春一樣，都將在我們的人生中謝幕。Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm - winds less than 2 mph, with no precipitation or humidity and l

46、imited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our day-to-day weather lives. It will climb higher than the tip of Mount Everest (5.5 miles/8.85 kilometers), drifting even higher than the cruising altitude of commerc

47、ial airliners (5.6 miles/9.17 kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence.The supersonic descent could happen as early as Sunda.The weatheThe balloon will slowly drift to the edge of space at 120,000 feet ( Then, I

48、would assume, he will slowly step out onto something resembling an Olympic diving platform.Below, the Earth becomes the concrete bottom of a swimming pool that he wants to land on, but not too hard. Still, hell be traveling fast, so despite the distance, it will not be like diving into the deep end

49、of a pool. It will be like he is diving into the shallow end. Skydiver preps for the big jumpWhen he jumps, he is expected to reach the speed of sound - 690 mph (1,110 kph) - in less than 40 seconds. Like hitting the top of the water, he will begin to slow as he approaches the more dense air closer

50、to Earth. But this will not be enough to stop him completely.If he goes too fast or spins out of control, he has a stabilization parachute that can be deployed to slow him down. His team hopes its not needed. Instead, he plans to deploy his 270-square-foot (25-square-meter) main chute at an altitude

51、 of around 5,000 feet (1,524 meters).In order to deploy this chute successfully, he will have to slow to 172 mph (277 kph). He will have a reserve parachute that will open automatically if he loses consciousness at mach speeds.Even if everything goes as planned, it wont. Baumgartner still will free fall at a speed that would cause you and me to pass out, and no parachute is guaranteed to work higher than 25,000 feet (7,620 meters).cause there24