7

Atmel AT24MAC402/602 [DATASHEET]

8807A–SEEPR–6/12

3.1

EUI-48 Support

The EUI-48 address is stored in the last six bytes of the AT24MAC402’s extended memory block as shown in Table 3-1.

For information on the protocol to read the EUI-48 value, see “Device Addressing” on page 10 and “Read Operations” on

page 15.

Table 3-1.

48-Bit EUI Address Memory Map Example

Using an EUI-48 Value in an EUI-64 Application: An EUI-64 compatible value can be generated from the EUI-48 value

contained in the AT24MAC402 by concatenating the 24-bit OUI, an FFFEh data value, and the 24-bit Extension

Identifier. This is commonly referred to as an Encapsulated EUI-48 value. However, Atmel recommends using the

AT24MAC602 which contains a true EUI-64 value so that post read processing is not required by the application.

3.2

EUI-64 Support

For applications that utilize an EUI-64 standard, the EUI-64 address is stored in the last eight bytes of the

AT24MAC602’s extended memory block. Similar to EUI-48, the EUI-64 standard consists of the same three byte OUI

coupled with a five byte extension identifier (see Table 3-2). Atmel generates this unique 40-bit data value coupled with

the OUI to guarantee a globally unique 64-bit EUI value and requires no additional data manipulation like other solutions

where the application must manually insert a two byte FFFEh value in between the OUI and Extension Identifier. For

information on how to read the EUI read protocol, see “Device Addressing” on page 10 and “Read Operations” on page

15.

Table 3-2.

64-Bit EUI Address Memory Map Example

Note:

1. The data values FFFEh and FFFFh are prohibited beginning from the 40-bit Extension Identifier in Byte 1

and Byte 2. These values are reserved for denoting an encapsulated MAC-48 or EUI-48 value for use in an

EUI-64 environment.

3.3

Non-Atmel OUI Programming Option

For customers with their own IEEE-assigned OUI or Company ID, Atmel offers the time saving option to manage and

deliver custom AT24MAC402/602 devices with their EUI-48/64 values uniquely pre-programmed at delivery. Contact

your local Atmel Sales Office for additional information.

48-Bit EUI

Description

24-Bit OUI

24-Bit Extension Identifier

Memory Address

9Ah

9Bh

9Ch

9Dh

9Eh

9Fh

EUI Data Value

FCh

C2h

3Dh

Byte 1

Byte 2

Byte 3

64-Bit EUI

Description

24-Bit OUI

40-Bit Extension Identifier

Memory Address

98h

99h

9Ah

9Bh

9Ch

9Dh

9Eh

9Fh

EUI Data Value

FCh

C2h

3Dh

Byte 1(1)

Byte 2(1)

Byte 3

Byte 4

Byte 5