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