Active production, 32 MHz Cortex-M0+ in a 20-pin TSSOP
The STM32L010F4P6: The ARM Cortex-M0+ core runs at 32 MHz, which is the throughput ceiling for this 32-bit single-core device. For a sensor node polling an ADC at 10 kHz and updating a display over SPI, that clock headroom leaves margin for the application stack without hitting the flash wait-state wall.
Memory budget and peripheral fit for a compact control loop
16 KB of on-chip flash and 2 KB of SRAM — the flash holds a modest firmware image (a UART protocol handler plus a PID loop fits), while the SRAM covers the runtime variables. There is also 128 bytes of embedded EEPROM, useful for calibration constants or configuration parameters that survive a power cycle without external storage. The peripheral set includes I²C, SPI, and UART/USART for serial communication, plus a 7-channel 12-bit ADC. That combination handles a typical mixed-signal front-end — reading analog sensors, talking to a digital temperature sensor over I²C, and reporting out over UART. 16 general-purpose I/O lines in the 20-TSSOP package mean every pin is accounted for.