W78E58B

8-BIT MICROCONTROLLER

Publication Release Date: March 18, 2002

- 1 -

Revision A3

1. GENERAL DESCRIPTION

The W78E58B is an 8-bit microcontroller which has an in-system programmable Flash EPROM for

firmware updating. The instruction set of the W78E58B is fully compatible with the standard 8052. The

W78E58B contains a 32K bytes of main ROM and a 4K bytes of auxiliary ROM which allows the

contents of the 32KB main ROM to be updated by the loader program located at the 4KB auxiliary

ROM; 512 bytes of on-chip RAM; four 8-bit bi-directional and bit-addressable I/O ports; an additional 4-

bit port P4; three 16-bit timer/counters; a serial port. These peripherals are supported by a eight

sources two-level interrupt capability. To facilitate programming and verification, the ROM inside the

W78E58B allows the program memory to be programmed and read electronically. Once the code is

confirmed, the user can protect the code for security.

The W78E58B 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

− DIP 40: W78E58B-24/40

− PLCC 44: W78E58BP-24/40

− QFP 44: W78E58BF-24/40