参数资料
型号: DS18S20-PAR
厂商: MAXIM INTEGRATED PRODUCTS INC
元件分类: Switch/Digital Output Temperature Sensor
英文描述: DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, ROUND, THROUGH HOLE MOUNT
封装: TO-92, 3 PIN
文件页数: 19/20页
文件大小: 250K
代理商: DS18S20-PAR
DS18S20-PAR
8 of 20
It is very important to follow the transaction sequence every time the DS18S20-PAR is accessed, as the
DS18S20-PAR will not respond if any steps in the sequence are missing or out of order. Exceptions to
this rule are the Search ROM [F0h] and Alarm Search [ECh] commands. After issuing either of these
ROM commands, the master must return to Step 1 in the sequence.
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 slave devices (such as the DS18S20-PAR) are
on the bus and are ready to operate. Timing for the reset and presence pulses is detailed in the
1-WIRE SIGNALING section.
ROM COMMANDS
After the bus master has detected a presence pulse, it can issue a ROM command. These commands
operate on the unique 64–bit ROM codes of each slave device and allow the master to single out a
specific device if many are present on the 1-Wire bus. These commands also allow the master to
determine how many and what types of devices are present on the bus or if any device has experienced an
alarm condition. There are five ROM commands, and each command is 8 bits long. The master device
must issue an appropriate ROM command before issuing a DS18S20-PAR function command. A
flowchart for operation of the ROM commands is shown in Figure 9.
SEARCH ROM [F0h]
When a system is initially powered up, the master must identify the ROM codes of all slave devices on
the bus, which allows the master to determine the number of slaves and their device types. The master
learns the ROM codes through a process of elimination that requires the master to perform a Search ROM
cycle (i.e., Search ROM command followed by data exchange) as many times as necessary to identify all
of the slave devices. If there is only one slave on the bus, the simpler Read ROM command (see below)
can be used in place of the Search ROM process. For a detailed explanation of the Search ROM
procedure, refer to the iButton Book of Standards at www.ibutton.com/ibuttons/standard.pdf. After
every Search ROM cycle, the bus master must return to Step 1 (Initialization) in the transaction sequence.
READ ROM [33h]
This command can only be used when there is one slave on the bus. It allows the bus master to read the
slave’s 64-bit ROM code without using the Search ROM procedure. If this command is used when there
is more than one slave present on the bus, a data collision will occur when all the slaves attempt to
respond at the same time.
MATCH ROM [55h]
The match ROM command followed by a 64–bit ROM code sequence allows the bus master to address a
specific slave device on a multi-drop or single-drop bus. Only the slave that exactly matches the 64–bit
ROM code sequence will respond to the function command issued by the master; all other slaves on the
bus will wait for a reset pulse.
SKIP ROM [CCh]
The master can use this command to address all devices on the bus simultaneously without sending out
any ROM code information. For example, the master can make all DS18S20-PARs on the bus perform
simultaneous temperature conversions by issuing a Skip ROM command followed by a Convert T [44h]
command. Note, however, that the Skip ROM command can only be followed by the Read Scratchpad
[BEh] command when there is one slave on the bus. This sequence saves time by allowing the master to
iButton is a registered trademark of Dallas Semiconductor.
相关PDF资料
PDF描述
DS18S20Z DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, SURFACE MOUNT
DS18S20 DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, THROUGH HOLE MOUNT
DS18S20-SL+T&R DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, THROUGH HOLE MOUNT
DS18S20Z/T&R DIGITAL TEMP SENSOR-SERIAL, 9BIT(s), 0.50Cel, RECTANGULAR, SURFACE MOUNT
DS1963L-F5 SPECIALTY MEMORY CIRCUIT, MEDB2
相关代理商/技术参数
参数描述
DS18S20-PAR/T&R 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
DS18S20-PAR+T&R 制造商:Maxim Integrated Products 功能描述: 制造商:Maxim Integrated Products 功能描述:TEMP SENSOR DGTL 1-WIRE 3PIN TO-92 - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC THERM MICROLAN HI-PREC TO-92 制造商:Maxim Integrated Products 功能描述:Board Mount Temperature Sensors Prgmble Resolution 1-Wire Parasite Pwr
DS18S20-PAR+T&R 功能描述:板上安装温度传感器 Prgmble Resolution 1-Wire Parasite Pwr RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
DS18S20-SL/T&R 功能描述:板上安装温度传感器 RoHS:否 制造商:Omron Electronics 输出类型:Digital 配置: 准确性:+/- 1.5 C, +/- 3 C 温度阈值: 数字输出 - 总线接口:2-Wire, I2C, SMBus 电源电压-最大:5.5 V 电源电压-最小:4.5 V 最大工作温度:+ 50 C 最小工作温度:0 C 关闭: 安装风格: 封装 / 箱体: 设备功能:Temperature and Humidity Sensor
DS18S20-SL+T&R 制造商:Maxim Integrated Products 功能描述:TEMP SENSOR DGTL 1-WIRE - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC THERM MICROLAN HI-PREC TO-92 制造商:Maxim Integrated Products 功能描述:Board Mount Temperature Sensors Prgmble Resolution 1-Wire Parasite Pwr