GENERAL DESCRIPTION
MTU423 is a high-frequency, high-performance, 4-bit microcomputer-based universal remote controller. It contains a 4-bit ALU, ROM, RAM, input/output ports, timer, clock generator, index ROM and carrier control in a single chip. The high frequency (3.58Hz) provides a wide range of infrared carrier output. The 40Kx4 index ROM stores information of various remote controllers. The instruction set includes basic 4-bit instructions and special instructions such as index ROM moving, auto-incrementation and carrier control instruction.

FEATURES
• 4-bit microcomputer-based.
• Low current dissipation in STOP mode:
    - 1.0uA (typical) 3.58MHz (@ 3.0V)
• Powerful instruction set (73 instructions):
    - Binary addition, subtraction adjustment, logical operation in direct addressing mode and index addressing mode.
    - Single-bit manipulation instruction (set, reset, decision for branch).
    - 4-bit input/output instruction.
    - Various conditional branch instructions.
    - 8 working registers and manipulation instructions.
    - Index ROM data transfer instruction.
• ROM/RAM /Index ROM capacity:
    - ROM capacity 2048 x 16 bits.
    - RAM capacity 64 x 4 bits.
    - Index ROM capacity 40960 x 4 bits.
• Input/Output ports:
    - Input ports 2 ports/ 8pins (input port M/S).
    - I/O ports 2 ports/ 8pins (input/output port I/OA, I/OB).
• 2 control outputs: carrier, light.
• Built-in carrier duty cycle divider.
• One 6-bit programmable timer.
• 4 levels of stack for nest subroutine.
• Operating voltage: 2.4V ~ 3.6V.