Sinclair ZX Spectrum 128 Service Manual

Sinclair ZX Spectrum Service Manual
Spectrum For Everyone https://spectrumforeveryone.com/
4
1 SYSTEM DESCRIPTION
Introduction
Architecture
Z80A CPU
Memory Organisation
Read/Write Operations and Bus Arbitration
Input/Output
TV Picture Generation and Sound Output
Keyboard Scanning
Tape Interface
Programmable Sound Generator
RS232C/MIDI Interface
Keypad Scanning
Power Supplies
1.1 INTRODUCTION
The Spectrum 128 is a derivative of the 48K Spectrum Plus offering 128K of RAM, music quality sound,
greatly improved video quality and higher hardware reliability.
The firmware is capable of running in Spectrum 48K mode or alternative in 128K mode, which will
support paged memory in the form of a RAM disk. Extended BASIC to handle the sound facility is
provided, and a full screen editor is incorporated in the firmware.
A list of the principal features appears below:
a) 128K dynamic RAM
b) 32K ROM
c) Numeric keypad
d) TV sound with composite video
e) Elimination of dot crawl (single crystal operation)
f) RGB output
g) RS232 serial port
h) Musical instrument digital interface (MIDI)
i) Software compatible with all previous Spectrums
j) Edge connector compatible with Spectrum.

Sinclair ZX Spectrum 128 Specifications

General

Brand	Sinclair
Model	ZX Spectrum 128
Category	Desktop
Language	English