STMicroelectronics, 32 bit ARM Cortex M0+, STM32L031F6 Microcontroller, 32 MHz, 32kB FLASH, 20-Pin TSSOP

The access line ultra-low-power STM32L031x4/6 family incorporates the high-performance ARM® Cortex®-M0+ 32-bit RISC core operating at a 32 MHz frequency, high-speed embedded memories (up to 32 Kbytes of Flash program memory, 1 Kbytes of data EEPROM and 8 Kbytes of RAM) plus an extensive range of enhanced I/Os and peripherals.
The STM32L031x4/6 devices provide high power efficiency for a wide range of performance. It is achieved with a large choice of internal and external clock sources, an internal voltage adaptation and several low-power modes.
The STM32L031x4/6 devices offer several Analogue features, one 12-bit ADC with hardware oversampling, two ultra-low-power comparators, several timers, one low-power timer (LPTIM), three general-purpose 16-bit timers, one RTC and one SysTick which can be used as timebases. They also feature two watchdogs, one watchdog with independent clock and window capability and one window watchdog based on bus clock.