Overview
The LC573904 is a CMOS 4-bit microcontroller that operates on low voltage and very low power consumption. It also contains 4K-byte ROM, 128 × 4 bits RAM, LCD drivers and melody function.

Features
(1) ROM :4096 × 8 bits
(2) RAM :128 × 4 bits
(3) Cycle Time
(4) Input / Output Terminals
    - Input ports : 4 terminals (S-port : 4 terminals)
    - Input / Output ports : 8 terminals (P0 port : 4 terminals, P1 port : 4 terminals)
    [Notes] When using the P1 port for output, the “L” level hold Tr. of P1 should be OFF.
        If P1 port becomes “H” level with “L” level hold Tr. on, it causes the through current from VDD to GND and increases the current consumption.
    - Output ports : 2 terminals (Buzzer / melody output terminal : 1 terminal, General output port : 1 terminal)
    - LCD segment output ports : 32 terminals (Possible to use output port by mask option)
    - LCD common output ports : 4 terminals
(5) LCD driver
    - Built-in Step-up / Step-down circuit
(6) Melody/Buzzer
    - Melody function Octave : 3 octaves Time of musical note : specified by program
    - Buzzer output
(7) Base timer
    - 15-bit base timer for timekeeping
(8) HALT release
    - Five vectors
    1. 15-bit base timer (500ms overflow output)
    2. 15-bit base timer (output every 32ms)
    3. S-port
    4. P1-port
    5. 1/10 second pulse
(9) Stand-by mode
    - HALT mode
    The program operation will be stopped in this mode. This mode is released by system reset and 5 vectors for HALT release above-mentioned.
(10) System reset
    - RES terminal
    - Reset by setting S1 to S4 terminals to “H” level simultaneously.
(11) Oscillation
    - Two oscillation circuits
    - 32.768kHz crystal oscillation / RC oscillation
(12) Power supply
    - Ag-battery : VDD1-VSS=1.20V to 1.65V, Step-up voltage (VDD2-VSS=2.4V to 3.3V)
    - Li-battery : VDD2-VSS=2.50V to 3.60V, Step-down voltage (VDD1-VSS=1.25V to 1.8V)
    - External voltage supply : VDD2-VSS=2.00V to 6.00V, Step-down voltage (VDD1-VSS=1.3V to 3.0V)
(13) Shipping form
    - Bare chip, QFP64
(14) The development tool
    - Evaluation chip : LC5797
    - Emulator : EVA520 + TB5739 + DCB-1A