OKY3420-4 is a part of the OKYSTAR family of microcontrollers, which are used for a wide range of applications including automotive, industrial, and consumer applications. The OKY3420-4 is a 32-bit ARM Cortex-M4 based microcontroller with a built-in 120 MHz clock. It has a rich set of peripherals, including 2 UARTs, 3 SPIs, 3 I2Cs, 6 PWMs/timers/captures, 8 ADC channels, 2 interrupt controllers, and more. It also supports USB, Ethernet, and CAN communication.