【正文】 write 1, defined as high resistance input. 第 4 頁 P0 can be used for external program data storage, it can be defined as the eighth data/address. In FIASH programming, P0 mouth as the sourcecode input port, when FIASH check, the sourcecode P0 output, when P0 external must be pulled. P1 mouth: mouth is an internal P1 provide pullup resistors 8bit twoway I/O mouth, P1 mouth buffer can receive 4TTL gate current output. P1 mouth tube feet, was then write 1 for high, pull up inside can be used as input, P1 mouth be external pull down for low electricity at ordinary times, will output current, this is due to internal pull up sake. In FLASH programming and calibration, P1 mouth as eighth address to receive. P2 mouth: for an internal P2 mouth on the 8bit pullup resistors twoway I/O port, P2 mouth to receive, the output buffer 4 TTL gate current, when P2 mouth is written 1, its tube feet are internal pullup resistors, and push as input. And so as the input, P2 mouth feet are external down tube, will output current. This is due to internal pull up sake. P2 mouth when used external program memory or 16 address external data memory access, P2 mouth high output address eight. In a given address 1, it using internal and external 8 address advantage, when for reading and writing data memory, P2 when the special function registers mouth output of content. P2 mouth in FLASH programming and the calibration eight address when receiving high signal and control signals. P3 mouth: P3 mouth pipe is 8 feet with internal pullup resistors twoway I/O port, may receive four TTL gate current out put. When P3 mouth writing 1, they are internal and high level, and used as input. As input, due to external dropdown for low level, P3 mouth will output current (ILL) this is due to pull up39。該傳感器是采 用硅半導(dǎo)體集成工藝制成，因此亦稱硅傳感器或單片集成溫度傳感器。智能溫度傳感器內(nèi)部都包含溫度傳感器、 A/D 轉(zhuǎn)換器、 信號處理器、存儲器 (或寄存器 )和接口電路。此種產(chǎn)品測溫范圍大都在200℃ ~800℃ 之間，分辨率 12 位，最小分辨溫度在 ~ 之間。后三個數(shù) 碼管顯示所采集通道的溫度值，精確到 度。與 MCS51 兼容 兩個 16 位 定時器 /計數(shù)器 P0 能夠用于外部程序數(shù)據(jù)存儲器，它可以被定義為數(shù)據(jù) /地址的第八位。 P2 口當用于外部程序存儲器或 16 位地址外部數(shù)據(jù)存儲器進行存取時， P2 口輸出地址的高八位。 ALE/PROG：當訪問外部存儲器時，地址鎖存允許的輸出電平用于鎖存地址的地位字節(jié)。如果微處理器在外部執(zhí)行狀態(tài) ALE 禁止，置位無效。 XTAL2：來自反向振蕩器的輸出。它 集成了文件編輯處理、編譯連接、項目管理、窗口、工具引用和軟件仿 真調(diào)試等多種功能，是相當強大的開發(fā)工具。在由外部程序存儲器取指期間，每個機器周期兩次 /PSEN 有效。在平時， ALE第 10 頁 端以不變的頻率周期輸出正脈沖信號，此頻率為振蕩器頻 率的 1/6。 P2 口在 FLASH 編程和校驗時接收高八位地址信號 和控制信號。 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?？删幊檀型ǖ? 壽命： 1000 寫 /擦循環(huán) AT89C2051 是一種帶 2K 字節(jié)閃存可編程可擦除 只讀存儲器 的單片機。有的儀表還具有存儲功能，可存儲幾百到幾千組數(shù)據(jù)。智能溫度傳感器的特點 是能輸出溫度數(shù)據(jù)及相關(guān)的溫度控制量，適配各種微控制器 (MCU)；并且它是在硬件的基礎(chǔ)上通過軟件來實現(xiàn)測試功能的， 其智能化程度也取決于軟件的開發(fā)水第 7 頁 平。它是目前在國內(nèi)外應(yīng)用最為普遍的一種集成傳感器，典型產(chǎn)品有 AD590、 AD59 TMP1 LM135 等；模擬集成溫度控制器。 When/EA end keep high electricity at ordi