Apple 250 , PowerBook Duo 250 Computer Features 1

CHAPTER 1

Introduction to the PowerBook Duo 250 Computer

PowerBook Duo 250 Computer Features

The Macintosh PowerBook Duo 250 computer is a member of the PowerBook Duo family

of computers. It has all the basic features of the PowerBook Duo computer but also has

certain new features which are described in this note. These features include

■

an active-matrix (AM) 16-level grayscale display

■

a 200 MB hard drive

■

an inverter/speaker board that is compatible with both ﬁlm super-twist nematic

(FSTN) and AM displays

The computer uses the same 33 MHz 68030 microprocessor as the PowerBook Duo 230

computer. Chapter 2, “Hardware Modiﬁcations,” describes the modiﬁcations made to the

original PowerBook Duo computer to implement the PowerBook Duo 250 computer.

Chapter 3 describes the software modiﬁcations.

This note is a supplement to the

Macintosh Duo System Developer Note

, R0457LL/A, which

contains detailed information about the basic Macintosh PowerBook Duo computer.

PowerBook Duo 250 Computer Features 1

Features of the PowerBook Duo 250 computer are listed below. Items in boldface type are

unique to the PowerBook Duo 250 computer, and are described in more detail

later in this note. All other items are discussed in detail in the

Macintosh Duo System

Developer Note

■

main processor: 33 MHz 68030 microprocessor

■

main system controller (MSC): controls DRAM, ROM, built-in I/O, sound, and some

power-saving features

■

Power Manager: a custom microcontroller that provides intelligent power

management

■

integral hard disk: 120 MB or

200 MB capacity

■

4 MB of DRAM on the main logic board

■

DRAM connector: accommodates 4 MB or 8 MB Apple DRAM expansion card,

expanding system DRAM capacity to 8 MB or 12 MB; third-party developers using

15-Mbit DRAMs and current packaging techniques can design a card that expands

DRAM capacity up to 24 MB

■

1 MB of ROM: stores system and conﬁguration data.

■

active-matrix 16-level grayscale display

■

video components: a gray-scale controller chip (GSC) and video RAM; the GSC

controls the interface between the processor, the Video RAM, and the display; the

VRAMs store the data required to write and refresh the display

■

inverter/speaker board

compatible with both FSTN and AM displays

■

Combo chip: includes the Serial Communication Controller (SCC) and Small

Computer System Interface (SCSI) controller