參數(shù)資料
型號(hào): DS1821
元件分類: 溫度傳感器
英文描述: Programmable Digital Thermostat
文件頁數(shù): 9/16頁
文件大?。?/td> 570K
代理商: DS1821
DS1821
9 of 16
HARDWARE CONFIGURATION
Figure 4
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 this does not
occur and the bus is left low for more than 480
μ
s, all components on the bus will be reset.
TRANSACTION SEQUENCE
The protocol for accessing the DS1821 via the 1-Wire port is as follows:
Initialization
Function Command
Transaction/Data
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 DS1821 is on the bus and is ready to operate. For
more details, see the “1-Wire Signaling” section.
1-WIRE SIGNALING
The DS1821 requires strict protocols to insure data integrity. The protocol consists of several types of
signaling on one line: reset pulse, presence pulse, write 0, write 1, read 0, and read 1. All of these signals,
with the exception of the presence pulse, are initiated by the bus master.
The initialization sequence required to begin any communication with the DS1821 is shown in Figure 5.
A reset pulse followed by a presence pulse indicates the DS1821 is ready to send or receive data given the
correct function command.
The bus master transmits (TX) a reset pulse (a low signal for a minimum of 480
μ
s). The bus master then
releases the line and goes into a receive mode (RX). The 1-Wire bus is pulled to a high state via the 5K
pullup resistor. After detecting the rising edge on the DQ pin, the DS1821 waits 15-60
μ
s and then
transmits the presence pulse (a low signal for 60-240
μ
s).
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相關(guān)代理商/技術(shù)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(zhǔn)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(fēng)格: 封裝 / 箱體: 設(shè)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(zhǔn)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(chǎn)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(zhǔn)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(fēng)格: 封裝 / 箱體: 設(shè)備功能:Temperature and Humidity Sensor
DS1821-C04 制造商:DSC 功能描述: