參數(shù)資料
型號: DS1821
廠商: DALLAS SEMICONDUCTOR
元件分類: Switch/Digital Output Temperature Sensor
英文描述: DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), 1Cel, ROUND, SURFACE MOUNT
封裝: PR-35, 3 PIN
文件頁數(shù): 16/17頁
文件大?。?/td> 461K
代理商: DS1821
DS1821
Page 8 of 17
1-WIRE BUS SYSTEM
The 1-wire bus system uses a single bus master (i.e., a microprocessor) to control slave devices. The
DS1821 functions as a slave device when it is used in 1-wire mode; however, since the DS1821 is not
addressable or multi-droppable, a single 1-wire-mode DS1821 must be the only slave device on the bus.
All data and commands are transmitted least significant bit first over the 1-wire bus.
The following discussion of the 1-wire bus system is broken down into three topics: hardware
configuration, transaction sequence, and 1-wire signaling (signal types and timing).
HARDWARE CONFIGURATION
The 1-wire bus has by definition only a single data line. Each device (in this case, the master and one
DS1821) interfaces to the data line via an open drain or 3–state port. This allows each device to “release”
the data line when the device is not transmitting data so that the bus is available for use by the other
device. The 1-wire port of the DS1821 (the DQ pin) is open drain with an internal circuit equivalent to
that shown in Figure 6.
The 1-wire bus requires an external pullup resistor of approximately 5 k
; thus, the idle state for the 1-
wire bus is high. If for any reason a transaction needs to be suspended, the bus MUST be left in the idle
state if the transaction is to resume. Infinite recovery time can occur between bits so long as the 1-wire
bus is in the inactive (high) state during the recovery period. If the bus is held low for more than 480
s,
the DS1821 will be reset.
HARDWARE CONFIGURATION Figure 6
TRANSACTION SEQUENCE
The transaction sequence for accessing the DS1821 via the 1-wire port is as follows:
Initialization
DS1821 Function Command
Data Transmitted/Received
5 A
Typ.
RX
TX
DS1821 1-WIRE PORT
100
MOSFET
TX
RX
RX = RECEIVE
TX = TRANSMIT
VDD
4.7K
1-wire bus
DQ
Pin
Micro-
processor
相關PDF資料
PDF描述
DS1821T DIGITAL TEMP SENSOR-SERIAL, 8BIT(s), RECTANGULAR, THROUGH HOLE MOUNT
DS1822-PAR+T&R DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 2Cel, RECTANGULAR, THROUGH HOLE MOUNT
DS1822-PAR/T&R DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 2Cel, RECTANGULAR, THROUGH HOLE MOUNT
DS1822-PAR DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 0.20Cel, ROUND, THROUGH HOLE MOUNT
DS1822Z/T&R DIGITAL TEMP SENSOR-SERIAL, 12BIT(s), 2Cel, RECTANGULAR, SURFACE MOUNT
相關代理商/技術參數(shù)
參數(shù)描述
DS1821_07 制造商:DALLAS 制造商全稱:Dallas Semiconductor 功能描述:Programmable Digital Thermostat and Thermometer
DS1821+ 功能描述:板上安裝溫度傳感器 Programmable Digital Thermostat/Thrmmtr 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 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor
DS1821C+ 功能描述:恒溫器 Programmable Digital Thermo-stat/monitor RoHS:否 制造商:Maxim Integrated 功能: 開路溫度: 閉合溫度: 準確性:+/- 1 C 溫度范圍:- 55 C to + 125 C 電流額定值:500 uA 電壓額定值:2.7 V to 5.5 V 產品:Thermostats
DS1821-C02 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 關閉: 安裝風格: 封裝 / 箱體: 設備功能:Temperature and Humidity Sensor
DS1821-C04 制造商:DSC 功能描述: