Interface Selection

Generally, serial EEPROMs utilize 3 types of interfaces - Microwire, SPI, and I²C. Each provides distinct advantages. Users should select the ideal interface based on application requirements.

I²C

There is a limit to the number of MCU ports that can be used. When seeking to minimize the number of ports used for EEPROM I/F, I²C, which requires only 2 lines for MCU control, is recommended. Multiple EEPROMs can be connected on the same bus without adding ports, making I²C ideal when utilizing more than one EEPROM in the same set.

One drawback, however, is the relatively slow communication rate (400K to 1Mb/s). This limits the access time, rendering it unsuitable for high-speed applications.

SPI

For high-speed communication, SPI, which is capable of speeds up to 20Mb/s, is the preferred choice. Because higher speeds are possible, EEPROMs with capacities as much as 1Mbit are offered. However, SPI requires 4 wires for communication, double the amount of I²C.

Microwire

This older communication method is slower than SPI and is only available in smaller capacities. Also, like SPI, 4 wires are needed - twice as much as I²C.