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)