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DS1972_10 Datasheet

Download or read online Maxim Integrated DS1972_10 1024-Bit EEPROM iButton pdf datasheet.



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19-4888; Rev 3; 4/10
General Description
®
The DS1972 is a 1024-bit, 1-Wire
nized as four memory pages of 256 bits each in a
®
rugged iButton
package. Data is written to an 8-byte
scratchpad, verified, and then copied to the EEPROM
memory. As a special feature, the four memory pages
can individually be write protected or put in EPROM-
emulation mode, where bits can only be changed from
a 1 to a 0 state. The DS1972 communicates over the
single-conductor 1-Wire bus. The communication fol-
lows the standard 1-Wire protocol. Each device has its
own unalterable and unique 64-bit ROM registration
number that is factory lasered into the device. The reg-
istration number is used to address the device in a mul-
tidrop, 1-Wire net environment.
Access Control/Parking Meter
Work-in-Progress Tracking
Tool Management
Inventory Control
Maintenance/Inspection Data Storage
Examples of Accessories
PART
ACCESSORY
DS9096P
Self-Stick Adhesive Pad
DS9101
Multipurpose Clip
DS9093RA
Mounting Lock Ring
DS9093A
Snap-In Fob
DS9092
iButton Probe
Pin Configurations
F3 SIZE
F5 SIZE
3.10mm
5.89mm
0.51mm
0.51mm
BRANDING
52
0000006234FB
1-Wire
IO
IO
GND
GND
1-Wire and iButton are registered trademarks of Maxim
Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
1024-Bit EEPROM iButton
♦ 1024 Bits of EEPROM Memory Partitioned Into
EEPROM chip orga-
Four Pages of 256 Bits
♦ Individual Memory Pages Can Be Permanently
Write Protected or Put in EPROM-Emulation Mode
(“Write to 0”)
♦ Switchpoint Hysteresis and Filtering to Optimize
Performance in the Presence of Noise
♦ IEC 1000-4-2 Level 4 ESD Protection (±8kV
Contact, ±15kV Air, Typical)
♦ Reads and Writes Over a Wide Voltage Range
from 2.8V to 5.25V from -40°C to +85°C
♦ Communicates to Host with a Single Digital
Signal at 15.4kbps or 125kbps Using 1-Wire
Applications
Protocol
♦ Unique Factory-Lasered 64-Bit Registration
Number Ensures Error-Free Device Selection and
Absolute Traceability Because No Two Parts are
Alike
♦ Built-In Multidrop Controller for 1-Wire Net
♦ Chip-Based Data Carrier Stores Digital
Identification and Information, Armored in a
Durable Stainless-Steel Case
♦ Data Can Be Accessed While Affixed to Object
♦ Button Shape is Self-Aligning with Cup-Shaped
Probes
♦ 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
PART
16.25mm
DS1972-F5+
DS1972-F3+
2D
®
+ Denotes a lead(Pb)-free/RoHS-compliant package.
®
17.35mm
Features
Common iButton Features
Ordering Information
TEMP RANGE
PIN-PACKAGE
-40°C to +85°C
F5 iButton
-40°C to +85°C
F3 iButton
1

Summary of Contents

Page 1

... GND GND 1-Wire and iButton are registered trademarks of Maxim Integrated Products, Inc. ___ Maxim Integrated Products For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxims website at www.maxim-ic.com. 1024-Bit EEPROM iButton 1024 Bits of EEPROM Memory Partitioned Into ...

Page 2

EEPROM iButton ABSOLUTE MAXIMUM RATINGS IO Voltage Range to GND ...-0.5V to 6V IO Sink Current ...20mA Operating Temperature Range ...-40°C to 85°C Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These ...

Page 3

ELECTRICAL CHARACTERISTICS (continued -40°C to 85°C, unless otherwise noted.) (Note 1) A PARAMETER SYMBOL IO PIN: 1-Wire WRITE Write-Zero Low Time (Notes 2, 16, 17) Write-One Low Time (Notes 2, 17) IO PIN: 1-Wire READ Read Low Time ...

Page 4

EEPROM iButton Note 20: Interval begins t after the trailing rising edge on IO for the last time slot of the E/S byte for a valid Copy Scratchpad REHMAX sequence. Interval ends once the devices self-timed EEPROM programming cycle ...

Page 5

Detailed Description The DS1972 combines 1024 bits of EEPROM, an 8-byte register/control page with user read/write bytes, and a fully featured 1-Wire interface in a rugged iButton package. Each DS1972 has its own 64-bit ROM registration number ...

Page 6

EEPROM iButton MSB 8-BIT CRC CODE MSB LSB MSB Figure 3. 64-Bit Lasered ROM 1ST 2ND 3RD STAGE STAGE STAGE Figure 4. 1-Wire CRC Generator commands is described in Figure 9. After a ...

Page 7

Memory Access Data memory and registers are located in a linear address space, as shown in Figure 5. The data memory and the registers have unrestricted read access. The DS1972 EEPROM array consists of 18 rows of 8 bytes each. ...

Page 8

EEPROM iButton The protection-control registers determine how incom- ing data on a Write Scratchpad command is loaded into the scratchpad. A protection setting of 55h (write protect) causes the incoming data to be ignored and the target address main ...

Page 9

CRC-16 of the command, address (actual address sent), and data at the end of the Write Scratchpad command sequence. Knowing this CRC value, the master can compare it to the value it has cal- culated to decide if the ...

Page 10

EEPROM iButton BUS MASTER Tx MEMORY FUNCTION COMMAND 0Fh WRITE SCRATCHPAD? Y BUS MASTER Tx TA1 (T[7:0]), TA2 (T[15:8]) DS1972 SETS CLEARS SETS E[2:0] T[2:0] MASTER Tx DATA BYTE TO SCRATCHPAD DS1972 ...

Page 11

FROM FIGURE 7a 55h N COPY SCRATCHPAD? Y APPLICABLE TO ALL R/W MEMORY LOCATIONS. BUS MASTER Tx TA1 (T[7:0]), TA2 (T[15:8]) AND E/S BYTE Y AUTH. CODE T[15:0] < 0090h? MATCH? N DURATION: t BUS MASTER Rx "1"s N MASTER ...

Page 12

EEPROM iButton Copy Scratchpad [55h] The Copy Scratchpad command is used to copy data from the scratchpad to writable memory sections. After issuing the Copy Scratchpad command, the master must provide a 3-byte authorization pattern, which should have been ...

Page 13

BUS MASTER Rx Tx OPEN-DRAIN Figure 8. Hardware Configuration All transactions on the 1-Wire bus begin with an initial- ization sequence. The initialization sequence consists of a reset pulse transmitted by the bus master followed by presence pulse(s) transmitted by ...

Page 14

EEPROM iButton FROM MEMORY FUNCTIONS FLOWCHART (FIGURE 7) BUS MASTER Tx ROM FUNCTION COMMAND 33h READ ROM COMMAND DS1972 Tx FAMILY CODE (1 BYTE) DS1972 Tx SERIAL NUMBER (6 BYTES) DS1972 Tx CRC BYTE Figure ...

Page 15

TO FIGURE 9a FROM FIGURE 9a FROM FIGURE 9a TO FIGURE 9a NOTE: THE OD FLAG REMAINS THE DEVICE WAS ALREADY AT OVERDRIVE SPEED BEFORE THE OVERDRIVE-MATCH ROM COMMAND WAS ISSUED. Figure 9b. ROM Functions Flowchart (continued) ...

Page 16

EEPROM iButton To maximize the data throughput in a multidrop envi- ronment, the Resume command is available. This com- mand checks the status of the RC bit and set, directly transfers control to the memory function ...

Page 17

MASTER Tx "RESET PULSE" V PUP V IHMASTER ILMAX RESISTOR Figure 10. Initialization Procedure: Reset and Presence Pulse Read/Write Time Slots Data communication with the DS1972 takes place in time slots that ...

Page 18

EEPROM iButton WRITE-ONE TIME SLOT t W1L V PUP V IHMASTER ILMAX RESISTOR WRITE-ZERO TIME SLOT V PUP V IHMASTER ILMAX RESISTOR READ-DATA ...

Page 19

Improved Network Behavior (Switchpoint Hysteresis 1-Wire environment, line termination is possible only during transients controlled by the bus master (1-Wire driver). 1-Wire networks, therefore, are suscep- tible to noise of various origins. Depending on the physical size and ...

Page 20

EEPROM iButton 1ST 2ND STAGE STAGE 9TH 10TH 11TH STAGE STAGE STAGE Figure 13. CRC-16 Hardware Description and Polynomial by the bus master. The DS1972 transmits this CRC only ...

Page 21

Command-Specific 1-Wire Communication ProtocolColor Codes Master to Slave Slave to Master Write Scratchpad (Cannot Fail) RST PD Select WS TA <8T[2:0] bytes> CRC-16 FF Loop Read Scratchpad (Cannot Fail) RST PD Select RS TA-E/S <8T[2:0] bytes> CRC-16 FF Loop Copy ...

Page 22

EEPROM iButton Memory Function Example Write to the first 8 bytes of memory page 1. Read the entire memory. MASTER MODE ...

Page 23

... Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 ___ 23 © 2010 Maxim Integrated Products ...

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