The MSC1200-01/1200V-01 is a Bi-CMOS display driver for 1/2-duty vacuum fluorescent display tube. This device consists of a 64-bit shift register, latches, an analog dimming circuit, a digital dimming circuit, a keyscan circuit, and drivers. The interface with a microcomputer can be done only with four signal lines (CS, DATA I/O, CLOCK, and INT). Also, the DATA I/O and CLOCK signal lines can be shared with other peripherals by using the chip select function.