计算机专业毕业的设计外文翻译19.docxVIP

外文资料原文DS1820FEATURES? Unique 1–WireTM interface requires only one port pinfor communication? Multidrop capability simplifies distributed temperaturesensing applications? Requires no external components? Can be powered from data line? Zero standby power required? Measures temperatures from –55°C to +125°C in0.5°C increments. Fahrenheit equivalent is –67°F to+257°F in 0.9°F increments? Temperature is read as a 9–bit digital value.? Converts temperature to digital word in 200 ms (typ.)? User–definable, nonvolatile temperature alarm settings? Alarm search command identifies and addressesdevices whose temperature is outside of programmedlimits (temperature alarm condition)? Applications include thermostatic controls, industrialsystems, consumer products, thermometers, or anythermally sensitive systemDESCRIPTIONThe DS1820 Digital Thermometer provides 9–bit temperature readings which indicate the temperature of the device. Information is sent to/from the DS1820 over a 1–Wire interface, so that only one wire (and ground) needs to be connected from a central microprocessor to a DS1820. Power for reading, writing, and performing temperature conversions can be derived from the data line itself with no need for an external power source. Because each DS1820 contains a unique silicon serial number, multiple DS1820s can exist on the same 1–Wire bus. This allows for placing temperature sensors in many different places.Applications where this feature is useful include HVAC environmental controls, sensing temperatures inside buildings, equipment or machinery, and in process monitoring and control.DETAILED PIN DESCRIPTIONOVERVIEWThe block diagram of Figure 1 shows the major componentsof the DS1820. The DS1820 has three main data components: 1) 64–bit lasered ROM, 2) temperature and sensor, 3) nonvolatile temperature alarm triggers TH and TL. The device derives its power from the 1–Wire communication line by storing energy on an internal capacitor during periods of time when the signa