The ML64P168 has two operation modes, microcontroller operation mode and PROM mode. The microcontroller operation mode is used to operate the ML64P168 like a ML64168 and the PROM mode is used to program or read the PROM. The ML64P168 is a low power 4-bit microcontroller incorporating the Oki's original CPU core nX4/30. The ML64P168 provides a minimum instruction execution time of 4.3s (@700kHz). The ML64P168 contains 8160-byte program memory, 512-nibble data memory, three 4-bit input-output ports, 4-bit input port, 4-bit output port, 2-channel RC oscillation type A/D converter, LCD driver for up to 120 segments, and buzzer output port.