【正文】 2 0 D S 1 8 B 2 04 .7 KGN D GN D GN DVC CVC C單 片機.... 圖 4 DS18B20 與單片機的接口電路 DS18B20 溫度傳感器與單片機的接口電路 DS18B20 可以采用兩種方式供電，一種是采用電源供電方式，此時 DS18B20的 1 腳接地， 2 腳作為信號線， 3 腳接電源。 顯示部分電路設(shè)計 74LS164 引腳功能及特性 4ls164 是一個串入并出的 8 位移位寄存器，他常用于單片機系統(tǒng)中，下面總結(jié)一下這個元件的基本知識． ＜ 74ls164 引腳 圖＞ 11 ＜ 74LS164 內(nèi)部功能圖＞ ＜ 74LS164 邏輯符合表＞ 串行輸入帶鎖存 時鐘輸入 ,串行輸入帶緩沖 異步清除 最高時鐘頻率可高達 36Mhz 功耗： 10mW/bit 74 系列工作溫度： 0176。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 information about dismissal and unfair dismissal, see Dismissal. You can make a claim to an employment tribunal, even if you haven39。 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。 Have declared the end of the encounter that haven39。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。 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。溫度轉(zhuǎn)換命令子程序流程圖如上圖，圖 9 所示 計算溫度子程序 計算溫度子程序?qū)?RAM 中讀取值進行 BCD 碼的轉(zhuǎn)換運算，并進行溫度值正負的判定，其程序流程圖如圖 10 所示。 10 對于 DS18B20 的讀時隙是從主機把單總線拉低之后，在 15 秒之內(nèi)就得釋放單總線，以讓 DS18B20 把數(shù)據(jù)傳輸?shù)絾慰偩€上。其輸出用于修 正減法計數(shù)器的預置值，只要計數(shù)器門仍未關(guān)閉就重復上述過程，直到溫度寄存器值大致被測溫度值。 高速暫存ＲＡＭ的第６、７、８字節(jié)保留未用，表現(xiàn)為全邏輯１。開漏單總線接口引腳。 5 ．振蕩器特性： XTAL1 和 XTAL2 分別為反向放大器的輸入和輸出。在 FLASH 編程期間，此引腳用于輸入編程脈沖。 P1 口： P1 口是一個內(nèi)部提供上拉電阻 的 8 位雙向 I/O 口， P1 口緩沖器能接收輸出 4TTL 門電流。 時鐘頻率 033mhz 本文介紹一種基于 AT89C51 單 片機的一種溫度測量及報警電路 ,該電路采用DS18B20 作為溫度監(jiān)測元件，測量范圍 0℃ ～ +100℃，使用 LED 模塊顯示，能設(shè)置溫度報警上下限。 在日常生活及工業(yè)生產(chǎn)過程中，經(jīng)常要用到溫度的檢測及控制，溫度是生產(chǎn)過程和科學實驗中普遍而且重要的物理參數(shù)之一。 從以上兩種方案，很容易看出，采用方案二，電路比較簡單，軟件設(shè)計 也比較簡單，故采用了方案二。 中斷喚醒省電模式 這是由于內(nèi)部上拉的緣故。此時， ALE只有在執(zhí)行 MOVX， MOVC 指令是 ALE 才起作用。 ．芯片擦除： 整個 PEROM 陣列和三個鎖定位的電擦除可通過正確的控制信號組合，并保持ALE 管腳處于低電平 10ms 來完成。 圖 2 DS18B20 內(nèi)部結(jié)構(gòu) 64 位 ROM 的結(jié)構(gòu)開始８位是產(chǎn)品類型的編號，接著是每個器件的惟一的序號，共有 48 位，最后８位是前面 56 位的 CRC 檢驗碼，這也是多個 DS18B20 可以采用一線進行通信的原因。 當符號位Ｓ＝０時，表示測得的溫度值為正值，可以直接將二進制位轉(zhuǎn)換為十進制；當符號位Ｓ＝１時，表示測得的溫度值為負值，要先將補碼變成原碼，再計算十進制數(shù)值。另一種是寄生電源供電方式，如圖4 所示單片機端口接單線總線，為保證在有效的 DS18B20 時鐘周期內(nèi)提供足夠的電流，可用一個 MOSFET 管來完成對總線的上拉。 C to 70176。t appealed against the disciplinary action your employer has taken against you. However, if you win your case, the tribunal may reduce any pensation awarded to you as a result of your failure to appeal. Remember that in most cases you must make an application to an employment tribunal within three months of the date when the event you are plaining about happened. If your application is received after this time limit, the tribunal will not usually accept i. If you are worried about how the time limits apply to you, take 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. 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 pensation if you win the case. This is known as a damagesbased agreement. In England and Wales, your solicitor can39。 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 that