"loki" was the Spectrum
that never was. When Sinclair's computer range was sold to Amstrad in 1986, a number of
next generation products were still in the pipeline but never came to fruition. Foremost
of these was the so-called Super Spectrum, the Low-cost Colour Computer (or LoCC,
inevitable codenamed "Loki"). It was intended to be an Amiga-beater, with custom
graphics and sound chips, a "huge" 512x256 resolution in up to 256 colours and a
128K memory. And all for under 200 pounds. This, of course, was completely unrealistic: at
the time, the Amiga cost 1.500 pounds, a price imposed by its sophisticated custom
hardware. In the event, Amstrad abandoned design work on the machine. The keyboard appears
to have influenced the design of the Spectrum 2 and 3 case, but otherwise nothing ever
emerged of the "Loki".
Super Spectrum - June 1986 - Sinclair User
At the time of the Amstrad deal Sinclair was well advanced with development plans for a
new Spectrum micro - the SuperSpectrum - and Sinclair User has now uncovered the full
details.
Designed to replace the Spectrum 128 at under £200, the SuperSpectrum - codenamed 'Loki'
after the Norse 'gamesplayer' god - is an entertainment software computer with
graphics and sound the likes of which have never been seen even at five times the price.
Inspiration for the SuperSpectrum undoubtedly comes from Commodore's incredible Amiga
machine. The key to the startling power of the SuperSpectrum - as with the Amiga - lies in
its special custom chips. The SuperSpectrum has two sophisticated chips handling the video
screen (Rasterop device) and sound synthesis, both with direct memory access.
This gives the machine the potential to produce incredibly fast 3D graphics manipulations
and sound of hi-fi quality.
But where the Amiga costs over £1,500, the SuperSpectrum will scrape in under £200.
The trick is that the SuperSpectrum is still an 8-bit machine. In fact, it even has a
Spectrum 48K compatible mode if you want it. The processor it uses is a special up-rated
version of the old Spectrum's Z80A. Called the Z80H, the new chip runs twice as fast, at
an incredible 7 MHz. At this speed there is time to provide a fast interrupt handler that
keeps pace with the video display, still leaving time to run programs faster than the
Spectrum 48K.
But the real power of the micro comes from the two custom chips. Because they have direct
access to the memory, during time which would otherwise be wasted, large amounts of screen
data can be moved about at speeds that the CPU couldn't manage, even if it had nothing
else to do.
To match the CPU, fast-access Ram is required, and the SuperSpectrum will be equipped with
two 64K banks each made up of two 256K-bit chips. One bank will be connected to both the
CPU and custom-built Rasterop video hardware and will normally hold the video information
and sound waveform tables. Bank switching is required to enable the 16-bit address bus
access to all the Ram. A 8-bit system allows a total address space of 1 Mbyte. At least
two banks will be occupied by Roms but the rest can be fitted with Ram expansion.
The display quality relies on using a 53K video Ram table. Even at 7Mhz a Z80 could not
manipulate this amount of data quickly enough to give reasonable animation, so the
custom-designed graphics Rasterop device is essential. It tranfers 8-bit data in the video
area from one address to another, and in the process can carry out logical functions using
data from the destination and source addresses and its own masking registers. Animation
and selective screen scrolling becomes an automatic process with the CPU only sending a
few instructions during each line interrupt.
Another idea taken from the Amiga is line drawing hardware - the SuperSpectrum will be
capable of remarkable 3D wire-frame graphics. The screen mode that will produce the best
games has a 256 by 212 pixel resolution and 64 colours. A single byte is used for each
pixel, leaving two bits spare for the Rasterop chip to use for bobs (blitter objects) that
give sprite-like animation and collision detection for multi-coloured graphic shapes.
The same principle of Ram sharing will allow sound synthesis of a high quality as
waveforms are stored in memory. Sound output, produced by an 8-bit digital to analogue
converter, can be heard through a TV speaker, stereo headphones or fed Into a hi-fi
system. An optional sound sampler will allow you to 'record' any sound that has a pitch
and use it as a musical voice. A music keyboard for the SuperSpectrum will be available as
an add-on.
While it's easy to be blinded by the SuperSpectrum's startling graphics and sound
qualities there are two other features which could be just as important to the machine's
success.
Although the SuperSpectrum will support cassettes - and Amstrad may well build a cassette
player into the main box - Softcards could become the new medium for program storage.
These credit card size Rom cards can hold a program up to 1 Mbyte in size and they are
cheap to manufacture.
The other feature which may attract Amstrad to the SuperSpectrum is the built-in CP/M
operating system - add a controller and disc drive and the SuperSpectrum fits neatly into
the Amstrad range, running the same utilities as the Amstrad CPC and PCW computers.
To give an idea of what might be achievable with the SuperSpectrum take a look at what the
Amiga can do. Nearly everyone who has seen an Amiga has had to completely rethink their
expectations of other machines. It can perform lightning fast solid 3D tumbling, animation
approaching true cartoon quality and produce digitally sampled sound - real voices, real
jet engine roar.
The SuperSpectrum won't equal the Amiga for speed but it will come pretty close, and be
able to produce very similar effects at a fraction of the cost.
The big question is: Will Amstrad market the SuperSpectrum now they have the rights to it?
They'd be crazy not to. With the Sinclair technology and Amstrad's marketing the
SuperSpectrum - Loki 'the gamesplayer' - would take the world by storm.
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Keyboard
One feature that will mark out the SuperSpectrum as different from every Sinclair micro
before, will be a keyboard suitable for the fastest of typists. With word-processing such
a major attraction to people who would not consider buying a computer for games, a good
keyboard is essential. Another change will be the lack of keyword legends associated with
48K Spectrum Basic. The Basic is a development of the QL's SuperBasic and an additional
method of entering information will be via a light pen, supplied as standard.
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Memory
In standard form there will be 128K of Ram. With half of it taken up by video and sound
bitmaps this may not seem too generous, but bank switching is provided to allow expansion.
It is intended that most software will be stored in Rom - up to 1Mbyte on special
Softcards - leaving plenty of free Ram for workspace. SuperBasic, text, animation
graphics, sound and music editors as well as CP/M wlll be built-in, and the SuperSpectrum
Softcard Rom slot will also be standard, glvlng instant program loading for users and
piracy protection for software houses.
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Z80H microprocessor
Sinclair computers before and after the QL have used the Zilog Z80A CPU, triggered by
clock pulses to run at 3.5 MHz. The Z80H allows the SuperSpectrum to run at 7MHz so that
all processing functions run in half the time, whether they are number crunching, data
handling or screen printing.
The additional speed not only means faster programs - a powerful interrupt facility will
keep pace with the screen display without slowing down the CPU to any appreciable extent.
Games programmers wlll delight in belng able to change screen mode on every line of the
display.
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Sound generation
Rather than rely on a standard sound chip, the SuperSpectrum will have custom-built
synthesiser hardware, so it won't sound like any other computer, Amiga excepted. What it
will sound like is a Fairlight synth - in other words, virtually anything you want.
Waveforms are held in Ram and read out at various speeds with filterlng and envelope
control. There will also be a Midi interface, stereo inputs and outputs (Walkman style)
and built-in music composing.
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Input and output
The list of connections to the new machine is very impressive. A fully buffered Z80
expansion bus, RGB, composite and TV video, floppy disc, serial printer, twin joystick,
light pen, network and cassette ports should keep most people happy. Specialists will
welcome the Midi In, Out and Thru and stereo sound input, output and Walkman-style
headphone jacks. Also the genlock input which will lock the SuperSpectrum's video hardware
to video recorders, Laservision optical disc players and a frame grabber. The light pen is
fitted as standard.
Peripherals options include floppy disc drive, music keyboard and Ram expansions. Hard
disc, compact disc optical Rom drive, mouse, modem and audio and video grabbers are also
supported.
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Spectrum compatible
The machine will be Spectrum 48K compatible. Inside the SuperSpectrum wlll be faithful
copies of the old Roms. The video hardware can switch to the old format and the CPU clock
will slow down to 3.5Mhz. With the same cassette interface available, it seems likely then
that a high proportion of Spectrum software wlll run in a special compatible mode whlch
can be selected. You will not be able to write Spectrum Basic programs as the old Basic
Rom wlll be hidden from the user (do you want to write half-speed programs?) though
programs whlch use it will be able to access it when loaded. What may concern some people
will be the lack of a Microdrive interface. Microdrives it would seem are well out of
favour. Also there are no plans to include the sound chip from the 128, so true 128
compatibility seems unlikely.
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Video display
If you think that some remarkable effects have been achieved on the Spectrum screen,
you've seen nothing yet - the SuperSpectrum can rival the state-of-the-art graphics
handling of the Amiga. With nearly six times more memory devoted to video Ram, the display
has the same horizontal resolution as a QL (512 pixels) - but 16 colours are available!
Cut the number of pixels per line to 256 and you have two options: 256 colours, or 64
colours and four sprite planes. To handle this vast potential, custom graphics, blitter
technology in the form of custom graphics handling, sprite and collision detection
hardware, the Rasterop chlp (similar to the Amiga's blitter chip) will be built in. This
can access the screen Ram directly, so graphic operations can be performed very quickly.
Rasterop will also contain a light-pen interface.
Processor:
Z80H running at 7Mhz
RAM:
-128K expandable to 1MB
Storage:
-Cassete tapes
-Optional Floppy disk/Hard-disk
Firmware:
-derivate of QL SuperBASIC
Screen:
-512x256 256 colours
Other:
-Expansion Bus
-RGB/composite/TV
-Custom sound chip
-"Rasterop" blitter chip
-Printer
-light pen
-serial network
-midi
-extra ram
-RS232
-Miniature loudspeaker
-ROM cartridge slot