The STM32L452CCU6: The pad also serves as the primary ground return — the layout should connect it to the PCB ground with at least four vias inside the pad footprint.
Peripheral set and I/O budget
38 I/O lines are available in the 48-pin package. The connectivity block includes CANbus, USB, QSPI, SAI, and multiple UART/SPI/I2C interfaces — enough to drive a small display, log data to an external serial flash, and talk to a fieldbus gateway on the same chip. The 10-channel 12-bit ADC and single 12-bit DAC let the MCU handle analog sensor conditioning and analog output without an external converter, though the ADC's effective resolution depends on the reference noise and layout — a clean analog ground split is worth the board area.