原标题：Maxim的DS28EA00的单总线测温系统

　　采用支持菊链模式的新型数字温度传感器芯片DS28EA00组建的单总线测温网络。无需进行传统的ROM搜索步骤，允许用户将器件在链路中的物理位置与序列号对应，节省了RAM开销，简化了基于单总线的应用设计。

　　基本特点：

　　DS28EA00数字温度传感器是具有9位(0.5℃)至12位(1/16℃)分辨率和用户可编程非易失性(NV)上、下触发点报警功能的数字温度计。每个DS28EA00都具工厂编程的唯一64位序列号。通信时只需一根数据线和地线，就可通过1-Wire?协议串行传输数据。改进型1-Wire接口具有滞回和干扰滤波功能，使得 DS28EA00能够在大的1-Wire网络中可靠工作。与其他1-Wire温度计不同，DS28EA00具有两个额外的引脚用以执行顺序检测功能。该特性允许用户将器件在链路中的物理位置与序列号对应，例如，用来测量储存塔不同高度处的温度。如果无需顺序检测功能，这些引脚可作为通用输入或输出。 DS28EA00能够直接从数据线获取电源进行工作("寄生供电")，因此无需外部电源。

　　·数字温度计测量范围：-40℃至+85℃

　　·用户可选择的9至12位温度分辨率

　　·独特的1-Wire接口，仅需单个引脚即可进行通信

　　·每个器件都具有在工厂激光刻蚀的唯一64位序列号

　　·ROM多节点能力简化分布式温度检测应用

　　·具有滞回和干扰滤波器的改进型1-Wire接口

　　·用户可定义的非易失性(NV)报警温度设置/用户字节

　　·报警搜索命令能够快速确定温度超出设定范围的器件

　　·标准和高速1-Wire通信模式

　　·2个通用可编程IO (PIO)引脚

　　·级联功能使用PIO引脚检测器件在网络中的物理顺序

　　·工作范围：3.0V至5.5V，-40℃至+85℃

　　·可由数据线供电

　　方案特点

　　The DS28EA00 evaluation system (EV system) consists of a single evaluation kit (EV kit) that includes an evaluation board (EV board) made up of three subsections that can be broken/snapped off into three independently exercisable boards. Since one of the major features of the DS28EA00 is detection of physical sequence, a block of dip switches are provided on each subsection of the EV board to re-order the physical connection between the chips. Optionally, the customer can break off the subsections of the eval board, connect them together with the provided cables, and re-order the physical sequence of the DS28EA00s that way.

　　Easy Setup

　　Stand-Alone EV Board

　　Contains Three Separate, Breakable Subsections with a DS28EA00 Per Subsection

　　The Dipswitch Block on Each EV Board Subsection Routes Physical Chain-Mode

　　Connections Between Chips When Used as a Stand-Alone Board

　　EV Board’s Subsections are Breakable Into Three Separate Boards Each of Which Evaluates a Single DS28EA00 or, When Cabled Together, Evaluate Chain-Mode Searching

　　LEDs Give Visual Indicators of PIO Activity

　　6-Pin Terminal Strip Allows PIO Testing Outside of Chain Mode

　　PC Connectivity Included

　　RoHS Compliant

　　Free Downloadable Evaluation Software Available

　　参考原理图

　　图1 参考原理图