GENERAL DESCRIPTION
The W78C438C is a high-performance single-chip CMOS 8-bit microcontroller that is a derivative of the W78C58 microcontroller family. The W78C438C is functionally compatible with the W78C32, except that it provides either a 64 KB program/1 MB data memory address or memory-mapped chip select logic, five general I/O ports, and four external interrupts.

FEATURES
• 8-bit CMOS microcontroller
• Fully static design
• DC to 40 MHz operation
• ROM-less operation
• 256-byte on-chip scratchpad RAM
• Either 64 KB program/1 MB data memory address space or 4 memory-mapped chip select pins
• One 8-bit data/address port
• Two 8-bit and one 4-bit (optional) address ports
• Five 8-bit bidirectional I/O ports
    - Four 8-bit bit-addressable I/O ports and one 8-bit parallel I/O port
• Eight-source, two-level interrupt capability
• Three 16-bit timer/counters
• Four external interrupts
• One full-duplex serial channel
• Built-in power management
    - Idle mode
    - Power-down mode
• Packages:
    - 84-pin PLCC: W78C438CP-24/40
    - 100-pin PQFP: W78C438CF-24/40