Inter-integrated communication bus (I2C) is most often used for communicating with low-bandwidth peripherals, such as sensors and EEPROMs. Most often, an MCU will be configured as the I2C bus master with one or more slave I2Cs. However, many MCUs contain I2C controllers that can be used to implement either the master or slave side of I2C. There are many aspects of the I2C protocol that make it non-deterministic, such as the ability for slaves to hold the clock line until they are ready to receive more data (clock stretching) and multi-master arbitration.