W78E51C

Publication Release Date: April 20, 2005

- 3 -

Revision A2

1. GENERAL DESCRIPTION

The W78E51C is an 8-bit microcontroller which can accommodate a wider frequency range with low

power consumption. The instruction set for the W78E51C is fully compatible with the standard 8051.

The W78E51C contains an 4K bytes Flash EPROM; a 128 bytes RAM; four 8-bit bi-directional and bit-

addressable I/O ports; an additional 4-bit I/O port P4; two 16-bit timer/counters; a hardware watchdog

timer and a serial port. These peripherals are supported by seven sources two-level interrupt

capability. To facilitate programming and verification, the Flash EPROM inside the W78E51C allows

the program memory to be programmed and read electronically. Once the code is confirmed, the user

can protect the code for security.

The W78E51C microcontroller has two power reduction modes, idle mode and power-down mode,

both of which are software selectable. The idle mode turns off the processor clock but allows for

continued peripheral operation. The power-down mode stops the crystal oscillator for minimum power

consumption. The external clock can be stopped at any time and in any state without affecting the

processor.

2. FEATURES

• Fully static design 8-bit CMOS microcontroller

• Wide supply voltage of 4.5V to 5.5V

• 128 bytes of on-chip scratchpad RAM

• 4 KB On-chip Flash EPROM

• 64 KB program memory address space

• 64 KB data memory address space

• Four 8-bit bi-directional ports

• One extra 4-bit bit-addressable I/O port, additional INT2 / INT3

(available on 44-pin PLCC/QFP package)

• Two 16-bit timer/counters

• One full duplex serial port(UART)

• Watchdog Timer

• Seven sources, two-level interrupt capability

• Built-in power management

• Code protection mechanism

• Packages:

− DIP 40: W78E51C-40

− PLCC 44: W78E51CP-40

− PQFP 44: W78E51CF-40