Core and memory — enough headroom for a sensor node or control loop
The STM32L081CBT6: Built around a 32 MHz ARM Cortex-M0+ core, this MCU delivers 32-bit performance with the power efficiency of the M0+ architecture — the 32 MHz clock is fast enough for real-time sensor polling, PID loops, or communication protocol handling without burning through the battery. On-chip memory includes 128 KB of Flash for program storage, 20 KB of SRAM for data and stack, and a separate 6 KB EEPROM block — the dedicated EEPROM means you can store calibration constants or configuration parameters without wearing out the Flash, which is a common pain point on cheaper MCUs that emulate EEPROM in Flash.
Peripherals and I/O — enough to talk to the outside world
The built-in brown-out detect and POR eliminate the need for a separate supervisor IC in most designs.