DS1994中文资料DALLAS数据手册PDF规格书

iButton DESCRIPTION

The DS1994 Memory iButton is a rugged read/write data carrier that acts as a localized database, easily accessible with minimal hardware. The nonvolatile memory and optional timekeeping capability offer a simple solution to storing and retrieving vital information pertaining to the object to which the iButton is attached. Data is transferred serially through the 1-Wire protocol that requires only a single data lead and a ground return.

SPECIAL FEATURES

■ 4096 bits of Read/Write Nonvolatile

Memory

■ 256-bit Scratchpad Ensures Integrity of Data

Transfer

■ Memory Partitioned into 256-bit Pages for

Packetizing Data

■ Data Integrity Assured with Strict

Read/Write Protocols

■ Contains Real-Time Clock/Calendar in

Binary Format

■ Interval Timer Can Automatically

Accumulate Time When Power is Applied

■ Programmable Cycle Counter can

Accumulate the Number of System PowerOn/Off Cycles

■ Programmable Alarms Can Be Set to

Generate Interrupts for Interval Timer,

RealTime Clock, and/or Cycle Counter

■ Write-Protect Feature Provides Tamperproof

Time Data

■ Programmable Expiration Date That Limits

Access to SRAM and Timekeeping

■ Clock Accuracy is Better Than ±2 Minutes/

Month at 25°C

■ Operating Temperature Range from -40°C to

+70°C

■ Over 10 Years of Data Retention

COMMON iButton® FEATURES

■ Unique, Factory-Lasered, and Tested 64-bit

Registration Number (8-bit Family Code +

48-bit Serial Number + 8-bit CRC Tester)

Assures Absolute Traceability Because No

Two Parts Are Alike

■ Multidrop Controller for MicroLAN

■ Digital Identification and Information by

Momentary Contact

■ Chip-Based Data Carrier Compactly Stores

Information

■ Data Can Be Accessed While Affixed to

Object

■ Economically Communicates to Bus Master

with a Single Digital Signal at 16.3kbps

■ Standard 16mm Diameter and 1-Wire®

Protocol Ensure Compatibility with iButton

Family

■ Button Shape is Self-Aligning with CupShaped Probes

■ Durable Stainless Steel Case Engraved with

Registration Number Withstands Harsh

Environments

■ Easily Affixed with Self-Stick Adhesive

Backing, Latched by its Flange, or Locked

with a Ring Pressed onto its Rim

■ Presence Detector Acknowledges when

Reader First Applies Voltage

■ Meets UL#913 (4th Edit.); Intrinsically Safe

Apparatus, Approved under Entity Concept

for Use in Class I, Division 1, Group A, B, C

and D Locations