High Quality Content by WIKIPEDIA articles! The EFM32 (Energy Friendly Microcontrollers) is a family of 32-bit RISC Flash microcontrollers designed by Energy Micro AS, based on Cortex-M3, Cortex-M0+ and Cortex-M4F cores from ARM Holdings. EFM32 is a mixed-signal microcontroller focusing on supporting ultra low power battery operated solutions. To run from small cell batteries, EFM32 MCUs incorporates low power peripheral technology, fast response time, low latency, and autonomous operation (i.e. the CPU does not run while the peripherals communicate). The EFM32 microcontrollers are offered in various configurations.