Package and mounting
The STM32L083RBT6: The ARM Cortex-M0+ core runs at 32 MHz — not a speed demon, but the right clock for an ultra-low-power part. The 128 KB Flash and 20 KB RAM define the firmware budget: enough for a modest RTOS, a USB stack, and a sensor-fusion library, but you will be counting bytes on a complex BLE or graphics application. The 6 KB embedded EEPROM is the standout — it saves an external serial EEPROM for parameter storage, which on a battery-powered board can cut both BOM cost and PCB area. Boots from internal Flash with the BOOT0 pin strapped low; the SWD debug port stays alive even with the independent watchdog enabled. The 32 MHz PLL requires the Flash wait state set to 1 before raising the core clock above 16 MHz, or the first branch instruction hard-faults.
The 64-LQFP package with 51 I/O gives enough pins for a parallel LCD interface plus sensor and actuator signals without multiplexing.