Amstrad ZX Spectrum +3 (1987)

Features

CPU: Zilog Z80A 3.5469MHz
RAM: 128kb
ROM: 64 kb (4 x 16k pages)
Text Modes: 32 x 24
Graphic Modes: 256 x 192
Colors: 8 with two tones each (normal and bright)
Sound: 3 channels, 8 octaves (Yamaha AY-3-8912)
I/O Ports: UHF PAL TV port, Serial interface (RS232) port, Parallel Printer port (8 bit), Auxiliary interface port, RGB Monitor (and PERITEL TV) port, MIDI output port, Two Joystick ports, Audio Out/Cassette port, Expansion I/O port (full Z80 bus), Second Disk Drive port
Keyboard: Full-stroke keyboard, QWERTY, 58 keys, arrow keys, TRUE VIDEO, INV VIDEO, DELETE, GRAPH, EXTEND MODE, EDIT, CAPS SHIFT (x2), CAPS LOCK, SYMB SHIFT (x2), BREAK
Built In Media: 3” Hitachi Floppy Disk Drive, single sided (40 track, 9 sector, 512 bytes/sector), CP/M compatible structure
OS: +3DOS
Built In Language: Spectrum BASIC 48K (compatibility mode) and 128K Spectrum ZX+3 BASIC, integrated with +3 DOS

Usage

MESS emulates the following computers

specpls3 [Amstrad ZX Spectrum +3]
specpl3e [Amstrad ZX Spectrum +3e] - enhanced version with HD support, v1.11

For each system, MESS supports the emulation of

a “cassette” (cass) device, for tapes in .wav, .tzx and .tap format
two floppy drives, “floppydisk1” (flop1) and “floppydisk2” (flop2), for disk images in .dsk format

Also notice that a “snapshot” (snap) feature is available for .sna, .z80 and .sp files, and a “quickload” (quik) is available for .scr files.

These systems require full keyboard emulation to work correctly. At startup, full keyboard emulation mode is enabled by default. Whilst in full keyboard emulation mode, some key associated functionality may be disabled (like the ESC key for EXIT). The keyboard emulation mode is toggled using the “Scroll Lock” key (by default).

BIOS options

Two variants of both specpls3 and specpl3e are supported (English and Spanish). You can switch between them, changing the -bios parameter. At command line,

"-bios 0" or "-bios en" = English

"-bios 1" or "-bios sp" = Spanish

Misc

A HTML version of the Spectrum 128 manual (converted by Damien Burke, with the approval of the copyright holder Amstrad) is available at: http://www.jetman.dircon.co.uk/speccy/128manua/index.html

History and Trivia

The Sinclair Spectrum +3 is the successor of the Spectrum +2, marketed one year earlier.

Just like the Spectrum+2 is a mix between the Spectrum 128 and the Amstrad CPC-464, the Spectrum +3 is a mix between the Spectrum 128 and the Amstrad CPC-6128. Indeed it has 3” disk-drive built-in the right-hand side of the case and a “real” full-stroke keyboard, just like the CPC-6128.

After the launch of the first Amstrad “Sinclair computer”, the Spectrum +2, they redesigned the motherboard and the content of the ROMs to produce the Spectrum +2A/B and +3. They also made some internal changes on the bus and removed the keypad scanning routines of the Spectrum 128 and +2 (remember the keypad sold with the Spanish Spectrum 128k).

As on the Spectrum +2, two BASIC versions are implemented: the 48k BASIC to remain compatible with the original Sinclair Spectrum, and the 128k BASIC which was already introduced with the Spectrum 128.

As with the others 128k models, and due to the limitations of the Z80 CPU which can only address 65536 bytes, the 128kb RAM is not directly usable (unless with bank-switching routines), but can be used as a RAM disk (drive M :).

So, the big change is the built-in 3” disk drive, exactly the same as the CPC-6128's drive. The operating system is called +3DOS and was developed by Locomotive Software Ltd who also conceived the CPC Basics and OS. So, of course, the +3DOS is very close to the CPCs disk operating system. The Amstrad FD-1 external drive can even be used with the Spectrum +3 as a second disk drive by connecting it directly to “DISK B PORT” at the back of the system.

The Spectrum +3 is considered the ultimate Spectrum model, gathering all the good points of the previous spectrum machines : 128k, convenient full-stroke keyboard, 3” built-in disk drive, 128k Basic, RAM disk, many interfaces… But sadly it was launched too late, at a time where the ST and the Amiga were already fighting on the shelves. It was the last official Sinclair Spectrum model ever made. The +2A and +2B models vere launched a little later, but were just a revision of the +2 model already marketed.

(info from old-computers.com)

About the +3 Enhanced

The ZX Spectrum +3e is an enhanced version of the Sinclair ZX Spectrum +3 home computer that was produced by Amstrad in the late '80s. The enhancement consists of an updated operating system (in ROM) that fixes many of the bugs in the original ROM, and adds lots of extra commands to +3 BASIC. One of the most important features of the new ROM, however, is that it supports the use of a hard disk with your Speccy, allowing you to store vast amounts of quickly-accessible software.

For those unwilling or unable to add a hard disk interface to their +3, the +3e ROMs still represent a useful update, providing such features as the ability to load Z80 snapshot files and access +3 disk files through the standard streams and channels interface.

To make your +3 (or black +2A) into a +3e, you need to install the new +3e ROM chips in your computer, and optionally add the hard-disk interface.