Description
The HD404344R series and HD404394 series 4-bit microcomputers are products of the HMCS400 series, which is designed to make application systems compact while realizing higher performance and increasing program productivity.

Features
•  Input/output pins
    ―  HD404344R series, HD4074344: 22 pins
        (10pins: Large-current I/O pins)
    ―  HD404394 series: 21 pins
        (3 pins: intermediate-voltage NMOS open drain I/O; 5 pins: NMOS open drain I/O with 15-mA high-current driver)
•  Two timer/counters
    ―  One timer output
    ―  One event counter input (with programmable edge detection)
•  8-bit clock-synchronous serial interface (1 channel)
•  On-chip A/D converter
    ―  HD404344R series, HD4074344: 8 bit × 4 channel
    ―  HD404394 series: 8 bit × 3 channel (with Vref pin)
•  Built-in oscillator
    ―  HD404344R Series
        Ceramic oscillator, CR oscillation, External clock drive is also possible.
    ―  HD404394 Series, HD4074344
        Ceramic oscillator, External clock drive is also possible.
•  Five interrupt sources
    ―  One by external source (with programmable edge detection)
    ―  Four by internal sources
•  Subroutine stack
    ―  Maximum 16 levels including interrupts
•  Two low-power dissipation modes
    ―  Standby mode
    ―  Stop mode
•  One input signal to return from stop mode
•  Instruction cycle time
    ―  1 µs (fOSC = 4 MHz)