外文翻譯---ds18b20單總線數(shù)字溫度計(jì)-資料下載頁
【導(dǎo)讀】獨(dú)特的單總線接口只占用一個(gè)I/O端口，而無需外圍元件；可以由總線提供電源，電壓適用范圍為~；測(cè)溫溫度范圍為-55℃~+125℃，在-10℃~+85℃范圍內(nèi)精度為±每個(gè)DS18B20含有一個(gè)唯一的64為ROM編碼；分辨率為12時(shí)最大轉(zhuǎn)換時(shí)間為750ms；報(bào)警搜索命令可識(shí)別哪片DS18B20溫度超限；DS18B20的內(nèi)部結(jié)構(gòu)如圖1所示。主要包括：寄生電源、溫度傳感器、64位。度上下限值的TM和TL觸發(fā)器、存儲(chǔ)和控制邏輯、8位循環(huán)冗余校驗(yàn)碼發(fā)生器等。DS18B20的溫度轉(zhuǎn)化位數(shù)設(shè)置為9，10,11,12位。總線上定位一只特定的DS18B20。中有和64位ROM序列不匹配的從機(jī)都將等待。遇到符合報(bào)警條件的情況，DS18B20才會(huì)響應(yīng)這條命令。只要DS18B20不掉電，報(bào)警狀態(tài)將一直保持，直到再一次。測(cè)得的溫度值達(dá)不到報(bào)警條件。這條命令向DS18B20的暫存器TH和TL中寫入數(shù)據(jù)?？刂破鞅仨氃谶@條命令發(fā)出后立即啟動(dòng)強(qiáng)上拉并最少保持10ms.DS18B20上電時(shí)自動(dòng)執(zhí)行，遮掩器件一上電暫存器里馬上就存在有效數(shù)據(jù)了。在這條命令之后發(fā)出數(shù)據(jù)隙，器件會(huì)輸出溫度轉(zhuǎn)換忙的標(biāo)識(shí)：0為忙，1為完成。
【正文】 HPAD [4EH] This mand allows the master to write 3 bytes of the data to the DS18B20’ s scratchpad. The first data byte is writer into the TH register, the second byte is written into the TL register, and the third byte is written into the configuration register. Data must be transmitted least significant bit first. All three bytes must be written before the master issues a reset, or the data may be corrupted. (8) READ SCRACHPAD [0BEH] This mand allows the master to read the contents of the scratchpad. The data transfer starts with the least significant bit of byte 0 and continues through the scratchpad until 9 byte (byte 8CRC) is read. The master may issue a reset to terminate reading at any time if only part of the scratchpad data is needed. (9) COPY SCRATCHPAD [48H] This mand copies the contents of the scratchpad TH,TL and configuration registers to EEPROM. If the device is being used in parasite power mode, within 10us (max) after this mand is issued the master must enable a strong pull up on the 1Wire bus for at least 10ms as described in the POWERING THE DS18B20 section. (10) RECALL E2 [B8H] This mand recalls the alarm trigger values (TH and TL) and configuration data from EEPROM, respectively, in the scratchpad memory. The master device can issue read time slots following the Recall E2 mand and the DS18B20 will indicate the status of the recall by transmitting 0 while the recall is progress and 1 when the recall is done. The recall operation happens automatically at powerup, so valid data is available in the scratchpad as soon as power is applied to the device.
鄂ICP備17016276號(hào)-1