The BU34675 is a compact 4-bit, single-chip microcontroller that includes all the I / O required for CD system control. Circuits on the chip include a pulse width measurement counter (PWC), SIO, and an LCD controller / driver for a 28-segment display. The LCD segments can all be switched in software to CMOS output, and the extensive I / O allows many functions with a low pin count.

Features
1) Low-voltage, high-speed operation (VDD = 2.3 to 5.5V at 4.4MHz).
2) Pulse width measurement counter on chip (for remote control reception).
3) SIO provided for communication with the DSP.
4) Seven-segment, four-common LCD controller / driver on chip.
5) All segments of the LCD controller / driver output can be switched to CMOS output using software.

Applications
    Portable CD-DA, CD / radio / cassette players