SN8P22121 is a 8-bit microcontroller (MCU) utilized CMOS technology and featured with low power consumption and high performance by its unique electronic structure. It is designed with the excellent IC structure including the program memory up to 4K-word OTP ROM, data memory of 192-byte RAM, 8-level stack buffers, two 8-bit timer (T0 and TC0), a watchdog timer, two interrupt sources (T0 and INT0), a SIO transceiver, and a full-speed USB SIE.