The ML63326 is a low power 4-bit microcontroller which incorporates the OKI original CPU core nX-4/250 and provides a minimum instruction execution time of 1s (@2MHz). It contains 24K-word program memory, 1536-nibble data memory, 4-bit input port, four 4-bit output ports, five 4-bit and 2-bit input-output ports, shift register, LCD driver for up to 1024 segments, and voice synthesis, including 1 megabit mask ROM for speech data, a 12-bit D/A converter and low-pass filter internally. Speech ROM size can be expanded externally with further 4 megabits. The ML63326 is suitable for applications such as games, toys, clocks etc. which use an LCD display and voice synthesis.