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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.

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 1-Wire Network

■ 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

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 Power-On/Off Cycles

■ Programmable Alarms Can Be Set to Generate Interrupts for Interval Timer, Real-Time 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