GENERAL DESCRIPTION
The W78C51D microcontroller supplies a wider frequency and supply voltage range than most 8-bit microcontrollers on the market. It is compatible with the industry standard 80C51 microcontroller series.

FEATURES
• Fully static design
• Supply voltage of 4.5V to 5.5V
• DC-40 MHz operation
• 128 bytes of on-chip scratchpad RAM
• 4K bytes of on-chip mask ROM
• 64K bytes program memory address space
• 64K bytes data memory address space
• Four 8-bit bidirectional ports
• Two 16-bit timer/counters
• One full duplex serial port
• Seven-source, two-level interrupt capability
• One extra 4-bit bit-addressable I/O port
• Two additional external interrupts INT2 / INT3
• Watchdog timer
• EMI reduction mode
• Built-in power management
• Code protection
• Packages:
    - DIP 40: W78C51D-24/40
    - PLCC 44: W78C51DP-24/40
    - QFP 44: W78C51DF-24/40