A Hardware Guide
For The BBC
Microcomputer


Misc.
Preface

1: INTRODUCTION

2: ATTITUDES TO WORK AND DISCIPLINES REQUIRED

2.1 Attitudes to Work and Working Environment
2.2 Anti-Static Precautions

2.3 Tools and equipment Required

2.4 Soldering

2.5 Desoldering

2.6 Defluxing

3: COMPLETE CIRCUIT DESCRIPTION

3.1 The Power Supply Unit
3.2 The Microprocessor (MPU)

3.3 The Clock Circuitry

3.4 Memory Devices

3.5 Random Access Memory

3.6 The Video Generating Circuitry

3.7 The Video Driving Circuitry

3.8 Cycle Stretching

3.9 The "Econet" Circuitry

3.10 The Keyboard Circuitry

3.11 The Cassette and RS423 Serial Interfaces

3.12 The Floppy Disc Interface

3.13 The User and Printer Ports

3.14 The Reset Circuitry

3.15 The Analogue Port

3.16 The Voice Synthesiser

3.17 The Sound Generator and Audio Amplifier

3.18 The 1MHz Bus Interface

3.19 FRED
3.20 Glitches

3.21 Double Accessing

3.22 NPGFD (JIM)

3.23 General Guidelines For Use of the 1MHz Bus

4: LINK SETTINGS AND FUNCTIONS

4.1 Keyboard PCB Removal
4.2 Removing the Main PCB
4.3 Re-Assembling the Machine
4.4 Link Functions

5: MACHINE UPGRADING

5.1 Upgrading a Model "A" Machine to a Model "B" Machine
5.11 Insertion of IC's Into Sockets
5.12 Connectors
5.13 Adding the User/Printer Port
5.14 The RS423 Interface
5.15 The Analogue to Digital Converter (ADC) Upgrade
5.16 Testing the Analogue Input Port
5.17 The RGB (Red, Green, Blue) Primary Colour Output
5.18 The "Tube" Interface
5.19 Memory Upgrade
5.20 Sideways ROM Selection Upgrade
5.21 The 1 MHz Bus
5.22 Further Expansions
5.23 The Floppy Disc Expansion
5.24 The Speech Expansion
5.25 The "Econet" Expansion
5.26 The Second Processor Add-Ons

6: HINTS, TIPS AND MODIFICATIONS

6.1 The Cassette Interface
6.2 Sound Output From the BBC Microcomputer

6.3 Video Modifications and Hints

6.4 Speech Synthesiser Tips and Modifications

6.5 Analogue Port Modifications

6.6 Printer Modifications and Tips

6.7 Keyboard Hints

6.8 Sideways ROM Socket
6.9 Disc Interface Modifications
6.10 RS423 Hint

INDEX

APPENDIX 1 : MANUFACTURERS DATA SHEETS FOR MAIN INTEGRATED
CIRCUIT DEVICES USED IN THE BBC MICROCOMPUTER.