USB-enabled EFM32™ Happy Gecko 32-bit MCUs Silicon Labs USB-enabled EFM32™ Happy Gecko 32-bit Microcontrollers are ideal for battery-operated applications and other systems requiring low energy and high performance. The MCUs are based on the powerful ARM® Cortex®-M0+ core. Happy Gecko MCUs have a standby current consumption of 900nA and consume less than 180µA per MHz while executing real-life code from Flash. Silicon Labs USB-enabled Happy Gecko 32-bit microcontrollers feature low-energy techniques, short wake-up time from energy-saving modes, and a wide selection of peripherals.