Description
The GMS77C1000 and GMS77C1001 are an advanced CMOS 8-bit microcontroller with 0.5K/1K words(12-bit) of EPROM. The Hynix Semiconductor GMS77C1000 and GMS77C1001 are a powerful microcontroller which provides a high flexibility and cost effective solution to many small applications. The GMS77C1000 and GMS77C1001 provide the following standard features: 0.5K/1K words of EPROM, 25 bytes of RAM, 8-bit timer/counter, power-on reset, on-chip oscillator and clock circuitry. In addition, the GMS77C1000 and GMS77C1001 supports power saving modes to reduce power consumption.

Features
• High-Performance RISC CPU:
    - 12-bit wide instructions and 8-bit wide data path
    - 33 single word instructions
    - 0.5K/1K words on-chip program memory
    - 25 bytes on-chip data memory
    - Minimum instruction execution time 200ns @20MHz
    - Operating speed: DC - 20 MHz clock input
    - Seven special function hardware registers
    - Two-level hardware stack
• Peripheral Features:
    - Twelve programmable I/O lines
    - One 8-bit timer/counter with 8-bit programmable prescaler
    - Power-On Reset (POR)
    - Power Fail Detector : noise immunity circuit 2 level detect ( 3V, 2.5V )
    - Internal Reset Timer (IRT)
    - Watchdog Timer (WDT) with on-chip RC oscillator
    - Programmable code-protection
    - Power saving SLEEP mode
    - Selectable oscillator options: Configuration word
        RC: Low-cost RC oscillator (200KHz~4MHz)
        XT: Standard crystal/resonator (455KHz~4MHz)
        HF: High-speed crystal/resonator (4~20MHz)
        LF: Power saving, low-frequency crystal/resonator (32~200KHz)
• CMOS Technology:
    - Low-power, high-speed CMOS EPROM technology
    - Fully static design
    - Wide-operating range:
        2.5V to 5.5V @ RC, XT, LF
        4.5V to 5.5V @ HF