Description
The GMS81C2012 and GMS81C2020 are advanced CMOS 8-bit microcontroller with 12K/20K bytes of ROM. These are a powerful microcontroller which provides a highly flexible and cost effective solution to many VFD applications. These provide the following standard features: 12K/20K bytes of ROM, 448 bytes of RAM, 8-bit timer/counter, 8-bit A/D converter, 10-bit High Speed PWM Output, Programmable Buzzer Driving Port, 8-bit Basic Interval Timer, 7-bit Watch dog Timer, Serial Peripheral Interface, on-chip oscillator and clock circuitry. They also come with high voltage I/O pins that can directly drive a VFD (Vacuum Fluorescent Display). In addition, the GMS81C2012 and GMS81C2020 support power saving modes to reduce power consumption.

Features
• 20K/12K bytes ROM(EPROM)
• 448 Bytes of On-Chip Data RAM (Including STACK Area)
• Minimum Instruction Execution time:
    - 1uS at 4MHz (2cycle NOP Instruction)
• One 8-bit Basic Interval Timer
• One 7-bit Watch Dog Timer
• Two 8-bit Timer/Counters
• 10-bit High Speed PWM Output
• One 8-bit Serial Peripheral Interface
• Two External Interrupt Ports
• One Programmable 6-bit Buzzer Driving Port
• 60 I/O Lines
    - 56 Programmable I/O pins (Included 30 high-voltage pins Max. 40V)
    - Three Input Only pins: 1 high-voltage pin
    - One Output Only pin
• Eight Interrupt Sources
    - Two External Sources (INT0, INT1)
    - Two Timer/Counter Sources (Timer0, Timer1)
    - Four Functional Sources (SPI,ADC,WDT,BIT)
• 12-Channel 8-bit On-Chip Analog to Digital Converter
• Oscillator:
    - Crystal
    - Ceramic Resonator
    - External R Oscillator
• Low Power Dissipation Modes
    - STOP mode
    - Wake-up Timer Mode
    - Standby Mode
    - Watch Mode
    - Sub-active Mode
• Operating Voltage: 2.7V ~ 5.5V (at 4.5MHz)
• Operating Frequency: 1MHz ~ 4.5MHz
• Sub-clock: 32.768KHz Crystal Oscillator
• Enhanced EMS Improvement
    Power Fail Processor (Noise Immunity Circuit)