參數(shù)資料
型號: DS18B20P
廠商: DALLAS SEMICONDUCTOR
元件分類: Switch/Digital Output Temperature Sensor
英文描述: DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 0.50Cel, RECTANGULAR, SURFACE MOUNT
封裝: TSOC-6
文件頁數(shù): 3/26頁
文件大?。?/td> 387K
代理商: DS18B20P
DS18B20
11 of 26
INITIALIZATION
All transactions on the 1-Wire bus begin with an initialization sequence. The initialization sequence
consists of a reset pulse transmitted by the bus master followed by presence pulse(s) transmitted by the
slave(s).
The presence pulse lets the bus master know that the DS18B20 is on the bus and is ready to operate. For
more details, see the “1-Wire Signaling” section.
ROM FUNCTION COMMANDS
Once the bus master has detected a presence, it can issue one of the five ROM function commands. All
ROM function commands are 8 bits long. A list of these commands follows (refer to flowchart in
Figure 5):
Read ROM [33h]
This command allows the bus master to read the DS18B20’s 8-bit family code, unique 48-bit serial
number, and 8-bit CRC. This command can only be used if there is a single DS18B20 on the bus. If more
than one slave is present on the bus, a data collision will occur when all slaves try to transmit at the same
time (open drain will produce a wired AND result).
Match ROM [55h]
The match ROM command, followed by a 64-bit ROM sequence, allows the bus master to address a
specific DS18B20 on a multidrop bus. Only the DS18B20 that exactly matches the 64-bit ROM sequence
will respond to the following memory function command. All slaves that do not match the 64-bit ROM
sequence will wait for a reset pulse. This command can be used with a single or multiple devices on the
bus.
Skip ROM [CCh]
This command can save time in a single drop bus system by allowing the bus master to access the
memory functions without providing the 64-bit ROM code. If more than one slave is present on the bus
and a Read command is issued following the Skip ROM command, data collision will occur on the bus as
multiple slaves transmit simultaneously (open drain pulldowns will produce a wired AND result).
Search ROM [F0h]
When a system is initially brought up, the bus master might not know the number of devices on the 1-
Wire bus or their 64-bit ROM codes. The search ROM command allows the bus master to use a process
of elimination to identify the 64-bit ROM codes of all slave devices on the bus.
Alarm Search [ECh]
The flowchart of this command is identical to the Search ROM command. However, the DS18B20 will
respond to this command only if an alarm condition has been encountered at the last temperature
measurement. An alarm condition is defined as a temperature higher than TH or lower than TL. The
alarm condition remains set as long as the DS18B20 is powered up, or until another temperature
measurement reveals a non-alarming value. For alarming, the trigger values stored in EEPROM are taken
into account. If an alarm condition exists and the TH or TL settings are changed, another temperature
conversion should be done to validate any alarm conditions.
相關(guān)PDF資料
PDF描述
DS18B20X DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 2Cel, RECTANGULAR, SURFACE MOUNT
DS18B20Z DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 0.50Cel, RECTANGULAR, SURFACE MOUNT
DS18B20 DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 0.50Cel, RECTANGULAR, THROUGH HOLE MOUNT
DS18B20U+T&R DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 0.50Cel, SQUARE, SURFACE MOUNT
DS18B20-SL+T&R DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 0.50Cel, RECTANGULAR, THROUGH HOLE MOUNT
相關(guān)代理商/技術(shù)參數(shù)
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DS18B20-PAR 功能描述:板上安裝溫度傳感器 RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor
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DS18B20-PAR+T&R 功能描述:板上安裝溫度傳感器 Prgmble Resolution 1-Wire Parasite Pwr RoHS:否 制造商:Omron Electronics 輸出類型:Digital 配置: 準確性:+/- 1.5 C, +/- 3 C 溫度閾值: 數(shù)字輸出 - 總線接口:2-Wire, I2C, SMBus 電源電壓-最大:5.5 V 電源電壓-最小:4.5 V 最大工作溫度:+ 50 C 最小工作溫度:0 C 關(guān)閉: 安裝風格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor