DS28E01-100+ Maxim Integrated, DS28E01-100+ Datasheet - Page 6

• Manufacturer Part Number: DS28E01-100+
• Description: EEPROM
• Manufacturer: Maxim Integrated

1Kb Protected 1-Wire EEPROM
with SHA-1 Engine
Each DS28E01-100 contains a unique ROM registration
number that is 64 bits long. The first 8 bits are a 1-Wire
family code. The next 48 bits are a unique serial number.
The last 8 bits are a cyclic redundancy check (CRC) of
the first 56 bits. See Figure 3 for details. The 1-Wire CRC
is generated using a polynomial generator consisting of
a shift register and XOR gates as shown in Figure 4. The
polynomial is X
about the 1-Wire CRC is available in Application Note
27: Understanding and Using Cyclic Redundancy
Checks with Maxim iButton
The shift register bits are initialized to 0. Then, starting
with the least significant bit of the family code, one bit
at a time is shifted in. After the 8th bit of the family code
has been entered, the serial number is entered. After
the 48th bit of the serial number has been entered, the
DS28E01-100
Figure 1. Block Diagram
iButton is a registered trademark of Maxim Integrated
Products, Inc.
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ABRIDGED DATA SHEET
®
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DS28E01-100
Products .
+ 1. Additional information
64-Bit Lasered ROM
1-Wire NET
1-Wire FUNCTION
SHA-1 FUNCTION
DATA MEMORY
CONTROL UNIT
256 BITS EACH
MEMORY AND
GENERATOR
4 PAGES OF
CONTROL
REGISTER
CRC-16
PAGE
PARASITE POWER
shift register contains the CRC value. Shifting in the 8
bits of the CRC returns the shift register to all 0s.
The DS28E01-100 has four memory areas: data memo-
ry, secrets memory, register page with special function
registers and user bytes, and a volatile scratchpad. The
data memory is organized as four pages of 32 bytes.
Secret and scratchpad are 8 bytes each. The scratch-
pad acts as a buffer when writing to the data memory,
loading the initial secret, or when writing to the register
page.
Refer to the full data sheet for this information.
ALGORITHM ENGINE
MEMORY 64 BITS
LASERED ROM
SECURE HASH
SCRATCHPAD
SECRETS
512-BIT
64-BIT
64-BIT
Memory Access
Maxim Integrated