MCx devices support an optional CRC to verify the I²C packet data integrity. An 8-bit CCIT polynomial ( (x⁸ + x²+ x + 1) with an initial value of 0xFF is used to calculate the CRC value. The CRC feature helps identify any data corruption in the I²C packet. When CRC is enabled for a read operation, MCx calculates the 8-bit CRC for the entire packet (Target ID + Write bit, Control Word (3 bytes), Target ID + Read bit, Data Bytes (2/4/8 bytes)) and appends the CRC at the end of packet; the primary I²C device (host) reading the data from MCx device can verify the CRC by comparing the received CRC (from MCx) against the calculated (by host) CRC. When CRC is enabled for a write operation, primary I²C device (host) writing data into MCx device needs to append the calculated 8-bit CRC for the entire packet (from Target ID + Write bit, Control Word (3 bytes), Data Bytes (2/4/8 bytes)) at the end of I²C data packet; I²C packet can be ignored in case of wrong or missing CRC (when enabled).

Refer device data sheet for detailed explanation on I²C packet communication using CRC.