This document describes the M-API v2.01 firmware libraries for use with the 78M6618 AC power and energy-monitoring IC. These metrology libraries are specifically designed for measurement and switch control of eight single-phase AC outlets (same phase). The libraries configure and operate the device's measurement front-end (e.g., mux, ADC, computation engine (CE), etc.) and provide simplified access to measurement output data such as power, voltage, current, accumulated energy, and line frequency. The M-API library computes all measurement calculations every accumulation interval and maps them to a dedicated block of registers reserved.