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SPECIAL FEATURES
§ 256-bit Electrically Erasable Programmable
Read Only Memory (EEPROM)
communicates with the economy of one
signal plus ground
§ EEPROM organized as one 256-bit page
§ 64-bit one-time programmable application
register is automatically write-protected after
programming
§ Reduces control, address, data, power, and
programming signals to a single data pin
§ 8-bit family code specifies DS1971
communications requirements to reader
§ Reads and writes over a wide voltage range
of 2.8V to 6.0V from -40°C to +85°C
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 16.3k bits per
second
§ Standard 16 mm 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 (application pending)
ORDERING INFORMATION
DS1971-F3 F3 MicroCan
DS1971-F5 F5 MicroCan
F3 MICROCANTM F5 MICROCANTM
All dimensions shown in millimeters.
DS1971
256-Bit EEPROM iButton
www.dalsemi.com
DATA
GROUND
0.36 0.51
3.10
c
1993
YYWW REGISTERED RR
54 14
000000FBC52B
16.25
17.35
DATA
GROUND
0.36 0.51
5.89
c
1993
YYWW REGISTERED RR
D4 14
000000FBD8B3
16.25
17.35
DS1971
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EXAMPLES OF ACCESSORIES
DS9096P Self-Stick Adhesive Pad
DS9101 Multi-Purpose Clip
DS9093RA Mounting Lock Ring
DS9093F Snap-in Fob
DS9092 iButton Probe
iButton DESCRIPTION
The DS1971 256-bit EEPROM iButton is a rugged read/write data carrier that identifies and stores
relevant information about the product or person to which it is attached. This information can be accessed
with minimal hardware: for example, a single port pin of a microcontroller. The DS1971 consists of a
factory-lasered registration number that includes a unique 48-bit serial number, an 8-bit CRC, and an 8-
bit Family Code (14H) plus 256 bits of EEPROM. The power to program and read the DS1971 is derived
entirely from the 1-Wire communication line. Data is transferred serially via the 1-Wire protocol which
requires only a single data lead and a ground return. The 48-bit serial number that is factory-lasered into
each DS1971 provides a guaranteed unique identity which allows for absolute traceability. The durable
MicroCan package is highly resistant to harsh environments such as dirt, moisture, and shock. Its compact
button-shaped profile is self-aligning with cup-shaped receptacles, allowing the DS1971 to be used easily
by human operators or automatic equipment. Accessories permit the DS1971 to be mounted on printed
circuit boards, plastic key fobs, photo-ID badges, ID bracelets, and many other objects. Applications
include work-in-progress tracking, electronic travelers, access control and storage of calibration
constants.
OVERVIEW
The block diagram in Figure 1 shows the relationships between the major control and memory sections of
the DS1971. The DS1971 has four main data components: 1) 64-bit lasered ROM, 2) 256-bit EEPROM
data memory with scratchpad, 3) 64-bit one-time programmable application register with scratchpad, and
4) 8-bit status memory. The bus master must first provide one of the ROM Function Commands before
the memory functions become accessible. All data is read and written least significant bit first.
The DS1971 contains the same memory chip as the DS2430A. For a full description of the logical
behavior, please refer to the DS2430A data sheet.
DS1971
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DS1971 BLOCK DIAGRAM Figure 1
