Microchip has announced serial EEPROM devices that feature a unique, pre-programmed 32-bit serial number for customers requiring unique IDs in their applications. For applications needing longer than 32-bit IDs, the unique ID can be extended to 48-bit, 64-bit, 96-bit, 128-bit and other lengths by increasing the number of bytes read from memory. Because the 32-bit ID is unique within these devices, any longer bit sequence is also unique. These 2 kb serial EEPROM devices are available in standard buses, such as I 2C, SPI and Microwire, and integrate up to 1.5 kb of memory that can be used as a standard EEPROM. In addition, Microchip has released a 256 kb I 2C unique-ID device, which, in addition to the 32-bit serial number, also contains the IEEE EUI-48 and IEEE EUI-64 MAC addresses. These IDs are in a write-protected area of the memory, giving users up to 224 kb of EEPROM to use in their applications. Microchip ensures this 32-bit ID is unique across the entire family of 24AA02UID, 24AA025UID, 11AA02UID, 25AA02UID and 24AA256UID unique-ID EEPROM devices. Microchip has also added to its existing EUI-48 MAC-address portfolio by introducing a family with pre-programmed EUI-64 MAC addresses. These 2 kb EEPROM devices are available in the I 2C,SPI and UNI/O buses, which provide easy and inexpensive access to MAC addresses, and feature up to 1.5 kb of EEPROM which can be used for storing configuration settings, or as a scratch-pad area for buffering small amounts of data. The 24AA02E64, 24AA025E64, 11AA02E64 and 25AA02E64 serial EEPROM devices have a built-in 64-bit Extended Unique Identifier (EUI) that is needed to identify the network hardware’s physical address. These built-in MAC addresses enable designers to buy addresses only when needed, and also eliminate the need for serialisation and programming.
The EUI-64 networking applications for the new EEPROMs are best suited for those involving Ethernet, Wi-Fi, Bluetooth, FireWire, ZigBee and Microchip’s MiWi protocols. The