16 MHz STM8 core — what the clock buys you
The STM8L101K3U6 runs its 8-bit STM8 core at 16 MHz. For a low-power line, 16 MHz is enough throughput to run a Modbus RTU slave or a PWM dimming sequence without waking a higher-performance core.
Memory map: 8 KB Flash, 1.5 KB RAM, 2 KB EEPROM
Program memory is 8 KB Flash — enough for a bootloader plus a modest application. The 1.5 KB SRAM handles stack and small buffers; the 2 KB EEPROM is the standout for this class: you can store calibration constants or fault logs without wearing the Flash. That EEPROM block is a real advantage over Flash-only MCUs when the firmware needs field-updatable parameters.
The internal oscillator saves an external crystal.
Package and I/O: 32-UFQFPN (5x5 mm), 30 I/O
The 32-UFQFPN package with exposed pad measures 5x5 mm — small enough for handheld or sensor-module PCBs. 30 I/O lines give you room for a parallel LCD data bus, keypad matrix, and a few spare GPIOs. Surface-mount only; no through-hole option.