Description
The GMS81C2020 and GMS81C2120 are an advanced CMOS 8-bit microcontroller with 20K/12K 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: 20K/12K bytes of ROM, 448 bytes of RAM, 8-bit timer/counter, 8-bit A/D convert er, 10-bit High Speed PWM Output, Programmable Buzzer Driving Port, 8-bit Basic Interval Timer, 7-bit Watch dog Timer, 8-bit, 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 GMS81C2020 and GMS81C2120 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 : 30 high-voltage pins (40V,max)
   - 3 Input Only pins : 1 high-voltage pin
   - 1 Output Only pin
• Eight Interrupt Sources
   - 2 By External Sources (INT0, INT1)
   - 2 By Timer/Counter Sources (Timer0, Timer1)
   - 4 By Functional Sources (SPI,ADC,WDT,BIT)
• 12-Channel 8-Bit On-Chip Analog to Digital Con verter
• Oscillatior :
   - Crystal
   - Ceramic Resonator
   - External RC Oscillator
   - Internal RCWDT Oscillatior
• Low Power Dissipation Modes
   - STOP mode
   - Wake-up Timer Mode
   - Standby Mode
   - Watch Mode
   - Subactive Mode
• Operating Voltage : 4.0V ~ 5.5V (at 4.5MHz)
• Operating Frequency : 0.4MHz ~ 4.5MHz
• Subclock : 32.768KHz Crystal Oscillator
• Enhanced EMS Improvement Power Fail Processor
   ( Noise Immunity Circuit )