DS1994L-F5 4-kbit Plus Time Memory iButton

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.

The scratchpad is an additional page that acts as a buffer when writing to memory. Data is first written to the scratchpad where it can be read back. After the data has been verified, a copy scratchpad command transfers the data to memory. This process ensures data integrity when modifying the memory. A 48-bit serial number is factory lasered into each DS1994L to provide a guaranteed unique identity that allows for absolute traceability. The durable MicroCan package is highly resistant to environmental hazards such as dirt, moisture, and shock. Its compact, coin-shaped profile is self-aligning with mating receptacles, allowing the DS1994L to be easily used by human operators.
Accessories permit the DS1994L to be mounted on almost any surface including plastic key fobs, photo-ID badges, and PC boards.

The DS1994L also includes time-keeping functions, a real-time clock/calendar, interval timer, cycle counter, and programmable interrupts, in addition to the nonvolatile memory. The internal clock can be programmed to deny memory access based on absolute time/date, total elapsed time, or the number of accesses. These features allow the DS1994L to be used to create a stopwatch, alarm clock, time and date stamp, logbook, hour meter, calendar, system power cycle timer, interval timer, and event scheduler.

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

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 Cup-Shaped 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

F5 MicroCAN