24AA02E48 Datasheet, PDF (6/18 Pages) Microchip Technology – 2K I2C™ Serial EEPROM with EUI-48™ Node Identity

24AA02E48
3.0 PRE-PROGRAMMED EUI-48™
NODE ADDRESS
The 24AA02E48 is programmed at the factory with a
globally unique, EUI-48™ and EUI-64™ compatible
node address stored in the upper half of the array and
permanently write-protected. The remaining 1,024 bits
are available for application use.
FIGURE 3-1:
MEMORY ORGANIZATION
00h
Standard
EEPROM
80h
Write-Protected
EUI-48™ Block
FFh
The 6-byte EUI-48 node address value is stored in
array locations 0xFA through 0xFF, as shown in
Figure 3-2. The first 3 bytes are the Organizationally
Unique Identifier (OUI) assigned to Microchip by the
IEEE Registration Authority. The remaining 3 bytes are
the Extension Identifier, and are generated by Micro-
chip to ensure a globally-unique, 48-bit value.
3.1 EUI-64™ Support
The pre-programmed EUI-48 node address can easily
be encapsulated at the application level to form a glob-
ally unique, 64-bit node address for systems utilizing
the EUI-64 standard. This is done by adding 0xFFFE
between the OUI and the Extension Identifier, as
shown below.
FIGURE 3-2:
EUI-48 NODE ADDRESS PHYSICAL MEMORY MAP EXAMPLE
Description
24-bit Organizationally
Unique Identifier
Data
00h
04h
A3h
Array
Address
FAh
24-bit Extension
Identifier
12h
34h
56h
FFh
Corresponding EUI-48™ Node Address: 00-04-A3-12-34-56
Corresponding EUI-64™ Node Address: 00-04-A3-FF-FE-12-34-56
4.0 WRITE PROTECTION
The upper half of the array (80h-FFh) is permanently
write-protected. Write operations to this address range
are inhibited. Read operations are not affected.
The remaining half of the array (00h-7Fh) can be
written to and read from normally.
DS22124B-page 6
© 2009 Microchip Technology Inc.