【正文】 芯片型號和制造廠商不同而異； OE—— ：讀選通信號輸入線，“ 0”有效； VCC：主電源輸入線，一般為＋ 5V； (B) 擴展方法 擴展程序存儲器時，一般擴展容量大于 256 字節(jié)，因此，除了由 P0 口提供低 8 位地址線外，還需由 P2口提供若干地址線，最大的擴展范圍位 64K 字節(jié)，即需 16 位地址線。擴展的程序存儲器究竟需要多少位地址線，應根據(jù)程序存儲器容量和選用的 EPROM 芯片容量而定。 2） 數(shù)據(jù)存儲器設計 由于算法的需要，在存儲器中需要存儲 24個從 A/D 片出來的數(shù)據(jù)，即需要24 單元的存儲單元。本設計采用鎳鉻 /鎳鋁熱電偶，此電偶用于 0℃～ 1000℃的溫度測量范圍，相應的輸出電壓為. 變送器由毫伏變送器和電流 /電壓變送器組成：毫伏變送器用于把熱電偶輸出的 變換成 010mA 范圍內(nèi)的電流；電流 /電壓變送器用于把毫伏變送器輸出的 010MA 電流變換成 05V范圍的電壓。 基于單片機的溫度控制系統(tǒng)設計 系統(tǒng)硬件設計 8 第三章 系統(tǒng)硬件設計 系統(tǒng)總體設計 系統(tǒng)控制主電路是由 8031及其外圍芯片，及一些輔助的部分構成的。 A,B,C 三個口可以作為擴展的 I/O 口使用， MCS－ 51 單片機的PO 口與 8155 的 AD0～ AD7 相連?？梢灾苯永?MOVX A,DPTR 或 MOVX DPTR,A 指令完成這三個口的讀 /寫（輸入 /輸出）操作。相應地址分配為： [2] 0000H00FFH 8155 內(nèi)部 RAM 0100H 命令 /狀態(tài)口 0101H A 口 0102H B 口 0103H C 口 0104H 定時器低八位口 0105H 定時器高八位口 基于單片機的溫度控制系統(tǒng)設計 系統(tǒng)硬件設計 10 A/D 轉(zhuǎn)換電路 圖 A/D轉(zhuǎn)換電路圖 ADC0809 的 IN0 和變送器輸出端相連，故 IN0 上輸入的 0V+5V 范圍的模擬電壓經(jīng) A/D 轉(zhuǎn)換后可由 8031 通過程序從 P0 口輸入到它的內(nèi)部 RAM 單元。在允許輸入信號 OE的控制下，再將轉(zhuǎn)換結果輸入到外部數(shù)據(jù)總線。圖 示出了可控硅管在給定周期 T 內(nèi)具有不同接通時間的情況。 通常，電阻爐爐溫控制采用偏差控制法。 TD— 微分時間 : T 積分時間 。為了系統(tǒng)正常工作， T1 中斷服務程序的執(zhí)行時間必須滿足 T0 的制一時間要求，因為 T1 的中斷是嵌套在 T0 中斷之中的。 本設計采用中值濾波，程序如下： FILTER: MOV A,2CH CJNE A,2DH,CAMP1 AJMP CMP2 CMP1: JNC CMP2 XCH A,2DH XCH A,2CH CMP2 MOV A,2DH CJNE A,2EH,CMP3 MOV 2AH,A RET CMP3: JC CMP4 MOV 2QH,A RET CMP4: MOV A,2EH CJNE A,2CH,CMP5 MOV 2AH,A RET CMP5: JC CMP6 XCH A,2CH CMP6: MOV 2AH,A RET 基于單片機的溫度控制 系統(tǒng)設計 系統(tǒng)軟件設計 20 圖 數(shù)字濾波程序流程圖 Y N N Y Y Y Y N Y Y N (2CH)送 A (2CH)≠ (2DH)? (2CH)(2DH)? (2CH)→← (2DH) (2DH)≠ (2EH)? (2DH)(2EH)? (2CH)≠ (2EH)? (2EH)(2CH)? (2CH) 送 2AH 返回 (2EH)送 2AH (2EH)送 2AH (2DH) 送 2AH (2DH) 送 2AH N 基于單片機的溫度控制系統(tǒng)設計 總結 21 總 結 本設計使用無 ROM 的 8031 作為主控芯片進行控制，單片機具有集成度高，通用性好，功能強，特別是體積小，重量輕，耗能低，可靠性高，抗干擾能力強和使用方便等獨特優(yōu)點，在數(shù)字、智能化方面有廣泛的用途。t 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 informu, take 基于單片機的溫度控制系統(tǒng)設計 參考文獻 23 advice from one of the anisations listed under Further 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 employment tribunal, you should get help straight away from one of the anisations listed under Further help. ation about dismissal and unfair dismissal, see Dismissal. You can make a claim to an employment tribunal, even if you haven39。s antiracism taskforce, is in London for the Football Association39。s 21 win. Michel Platini, president of European football39。 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, suddenly feel something, do it. 一字開頭的年齡已經(jīng)到了尾聲。 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 and 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。t 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 sweat profusely, looked at his thrown a basketball hoops, suddenly found himself has already can39。s time, your ideas are always special to clear. Want, want, line is clear, as if nothing could 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, or is a selfrighteous spiritual. 一個人的時候，自己的想法總是特別地清晰。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。 Have declared the end of the encounter that haven39。 instead of letting the world soften us, we let it drive us deeper into ourselves. We try to deflect the hurt and pain by pretending it doesn’t exist, but although we can try this all we want, in the end, we can’t hide from ourselves. We need to learn to open our hearts to the potentials of life and let the world soften us. 生活發(fā)生不幸時，我們常常會關上心門；世界不僅沒能慰藉我們，反倒使我們更加消沉。 Whenever a painful situation arises in your life, try to embrace it instead of running away or trying to mask the hurt. When the sadness strikes, take a deep breath and lean into it. When we run away from sadness that’s unfolding in our lives, it gets stronger and more real. We take an emotion that’s fleeting and make it a solid event, instead of something that passes through us. 當生活中出現(xiàn)痛苦的事情時，別再逃跑或隱藏痛苦，試著擁抱它吧；當悲傷來襲時，試著深呼吸，然后直面它。其實，我們有能力面對這些痛苦的感受，從中領悟到出路。與其一味顧慮重重，不如從局外人的角度看待決策之事。t. 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 there