SN8P1989 is a high-performance 8-bit microcontroller with the 12K-word of the OTP ROM. The SN8P1989 provides the following features: 512 bytes of RAM, Three 8-bit basic timer (T0,TC0,TC1),a watchdog timer, Three internal timer interrupts(T0, TC0, TC1), Two external interrupts(INT0, INT1),12bit ADC,16bit ADC ,a PGIA, a regulator, a integrated LCD driver for 4-common x 28 -segments LCD panel and a 8-level stack register. In addition, the SN8P1989 is a dual clock system, i.e. high-speed system clock and low-speed system clock. The high-speed system clock sources are generated from the external oscillator which includes three modules (Crystal/Ceramic, RC and external clock signal). The low-speed system clock is generated from on-chip low speed RC oscillator circuit (ILRC 16KHz@3v, 32KHz@5v).