The NXP MKL04Z32VFK4 is a 32-bit ARM Cortex-M0+ MCU from the Kinetis KL0 series, clocked at 48 MHz with 32 KB Flash and 4 KB RAM. It carries 22 GPIO, a 12-channel 12-bit ADC, and I²C, SPI, and UART/USART serial interfaces.
Memory and I/O — sizing the BOM line
32 KB Flash and 4 KB RAM place this part in the entry-level tier of the Kinetis KL0 family — enough for a single control loop, a few sensor reads, and a Modbus or custom serial protocol. The 22 GPIO and 12 ADC channels cover a small mixed-signal board without an external mux.