Spectrum +2

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The ZX spectrum +2 was Amstrad's attempt at a spectrum. There were actually two versions, one was based on the old Spectrum 128 circuit (Grey), and one was a redesign based on the +3 (Black) There are significant differences between the two, not least of which is that the Black one has +3DOS, a Centronics interface, and allows you to use drive letters to access the RAM disk instead of using arcane microdrive sequences which look not entirely unlike line noise.

I have a Grey one.

Contents 1 Specification (Grey speccy) 2 Part list 3 Add ons 4 My mods 5 IO Ports 5.1 General machine control port 5.2 Memory control 1 5.3 Sound 6 Ports 7 My speccy

[edit] Specification (Grey speccy)

• Z80 running at approx 3.5Mhz
• 128kb of ram
• 32kb of rom
• AY-3-8912 Audio

[edit] Part list

• 3.5Mhz Z80
• AY-3-8912 Audio
• Amstrad version of the 27256
• Astec UM1233 Video modulator

[edit] Add ons

I have a variety of add ons for this computer. All the items for the +3 are compatible with this computer.

[edit] My mods

My +2 has the hardware changes required to allow it to work with +3 Roms. I have replaced the roms with the +3E roms and simple hard drive interface, so it has an internal hard drive.

In addition, it also has the Dual colour power light

[edit] IO Ports

[edit] General machine control port

This port was the only one used on the unexpanded 48K, and it is used for both keyboard, border and Tape IO.

Write:

• 0 \
• 1 | Border colour (0-7)
• 2 /
• 3 Mic output bit

Read:

This is complex, the LSB of the port outputted is $FE. and the MSB is a strobe for they keyboard line. Each bit returned is one key. so:

• FEFE Shift->V
• FDFD A->G
• FBFE Q->T
• F7FE 1->5
• EFFE 0->6
• DFFE P->Y
• BFFE Enter->H
• 7FFE Space->B

Keys are active low.

[edit] Memory control 1

Address: 7FFD

• 0 \
• 1 | Ram page for the ram $C000 -> FFFF (0-7)
• 2 /
• 3 Page for display. 0 = page5, 1 = page7.
• 4 Rom select
• 5 Paging lock. If set, the current pages are locked until the next hard reset.

• 0: 128k editor, menu system and self-test program
• 1: 48 BASIC

[edit] Sound

• Address: (Write) $FFFD - Register select
• Address: (Read) $FFFD - Register read
• Address: (Write) $BFFD - Register write

[edit] Ports

The computer has the following ports:

• UHF out
• RGB-PERITEL
• AUX Sinclair format RS232
• RS232/Midi Sinclair format RS232/Midi
• Sinclair expansion port
• 9v power in

[edit] My speccy

The +2 is in pretty good condition. There are a number of wires soldered internally which are part of the modification for +3 roms, and the old 32k rom socket has a little board on it with a 128K rom in it. (although only 64k is currently used)

Loads of chips. the Later +2A was a +3 with half its electronics removed, bit this was a slightly redesigned Speccy 128. Note that the empty socket is where the CPU should go.

And on the lid is the keyboard and the tape deck.