The STM32U031x4/6/8 devices are ultra-low-power microcontrollers based on the high-performance Arm®Cortex®-M0+ 32-bit RISC core operating at a frequency of up to 56 MHz. The STM32U031x4/6/8 devices embed high-speed memories (up to 64-Kbyte flash memory and 12-Kbyte SRAM with hardware parity check), and an extensive range of enhanced I/Os and peripherals connected to APB and AHB buses, and a 32-bit multi-AHB bus matrix. They also embed protection mechanisms for embedded flash memory and SRAM, such as readout protection and write protection. The STM32U031x4/6/8 devices offer a 12-bit ADC, a 12-bit DAC, an embedded rail-to-rail analog comparator, one operational amplifier, a low-power RTC, one general-purpose 32-bit timer, one 16-bit PWM timer dedicated to motor control, three general-purpose 16-bit timers, and two 16-bit low-power timers The devices also embed up to 21 capacitive sensing channels. They also feature standard and advanced communication interfaces, namely three I2Cs, two SPIs, four USARTs and two low-power UARTs. The STM32U031x4/6/8 operate in the -40 to +85 °C (+105 °C junction) and -40 to +125 °C (+130 °C junction) temperature ranges from a 1.71 to 3.6 V VDD power supply using an internal LDO regulator. A comprehensive set of power-saving modes makes possible the design of low-power applications. Independent power supplies are supported: analog independent supply input for ADC, DAC, OPAMP and comparator, as well as VBAT input allowing the backup of the RTC and backup registers. The STM32U031x4/6/8 offer eight packages from 20 to 64 pins.