The BU8310AK, BU8311KS, and BU8313K are large-scale integrated circuits for telephones, which enable a serial input/output interface between the key input required for telephone panel boards and LED control functions. They reduce the number of wiring harnesses needed between the main board in the telephone and the panel board, and take some of the processing load off the main CPU.

FEATUREs
1) Keypad matrix interface
    1 Key input is output as 16-bit serial data.
    2 Internal chattering prevention circuit built into the key input circuit.

2) LED interface
    1 LED control commands input as 16-bit serial data.
    2 Bits with a pattern generator and pattern register can be assigned three independent flashing patterns in addition to being lighted or off.
    3 Power consumption can be reduced using RST pin input.
    4 LED on and off control can be initiated using ENA pin input or by commands setting all LEDs valid or invalid.

APPLICATIONs
    Telephones and cordless telephones