ZX Computings - OpenLibra

"The hi-res board seems to
go to a noticeably different kind
of 'clientele'. These seem to be
people who know more about
computing, and have been
waiting for someone to produce
a hi-res board." Even though
the high resolution board costs
£85, more than the computer,
Nick believes it has sold well
because it and the computer
can perform better than many
computers costing much more
than the combined price of the
board and ZX81. "Compared
with other machines which provide
the same facility, it is about
a third of the price", he said.
Quicksilva's latest project is
its most exciting one — a ZX
colour board.
"We'll definitely have one
soon", said Nick, "We're going
for eight colours. It is still in the
design stage (early March) but
we're well on the way to having
a working prototype.
"We hope to have one working
at the next Microfair. It will
probably have two kinds of control.
In one, you'll be able to
specify a particular colour for
each position on the screen. In
the other, we're going to have a
character code mode to specify
a particular colour map. It will
be controlled by simple POKEs.
The character code map idea is
a good one as it gives you the
same facility as you get with
the characters board. You can
use it with existing programs."
The Quicksilva idea is to
allow computer users to load
the colour and/or the character
generator software, and then
load in any game the user
already has to take advantage
of the programmable characters
and the colour.
The company which started
off with an ad swapped for its
first product now is four people
working full time. Nick's
sidekick is John Hollis, who has
done most of the design work.
"He's done everything except
the characters demo software
since the two of us started
up with Defender and the sound
board", said Nick. "As well as
that we have Mark Eyles, the
production manager, Chris London
who is a permanent 'PCB
production engineer' — or at
least that's what he calls
himself — along with Ellen the
post-person, and Steinar Lund
who does the zappy artwork for
the cassette covers."
And now what's around the
corner for Quicksitva? The colour
board seems certain to be a
winner. Quicksilva has also
recently developed an interface
to allow the Acorn Atom to run
a ZX printer, and they're working
on one for the VIC 20.
ZX COMPUTING SUMMER 1982
If you want to get an idea of
just how good the ZX81 can
be, take a good look at the products
which have come from
Nick Lambert's fertile mind.
Quicksilva —
The products
The High
Resolution
Graphics Board
The hi-res board comes with its
own test program in ROM
Hardware support
which you trigger with a simple
USR command, A test pattern
is drawn and the message "OS
HI RES TEST. . ALL OK" ap
pears. The hi-res board's
display is on a 256 by 192
matrix. Any particular point
may be white or black, and can
be referenced by its X and Y coordinates.
The effects generated by the
board are fantastic. We had
some samples running in the ZX
Computing offices when Nick
brought the stuff in to show us,
and my office became very
crowded as more and more
people came in to see the
marvellous board do its tricks.
The board is simple to use.
You call it with a USR command,
and the board follows instructions
stored in English in a
REM statement. For example,
REM BLACK CLEAR MOVE A A
DRAW B B, when A is zero and
B is 100, will clear to a white
area, and a line will be drawn in
black from the top left hand corner
(0,0) to somewhere near
the middle (100,100).
The graphics commands,
and what they do, are:
BLACK — sets the pen colour to
black.
WHITE — sets the pen colour to
white.
CLEAR — clears the whole
hi-res display to the opposite of
the pen colour.
MOVE X Y - This moves the
current co-ordinates (the hi-res
cursor) to X Y but does not
draw anything.
PLOT X Y — This plots a single
point in the current pen colour
at the X Y co-ordinate specified
DRAW X Y - This command
draws a line in the current pen
colour from the current coordinate
to the new co-ordinate
specified by X Y.
BOX X Y — This command,
which is found on few micros,
draws a rectangle from the current
co-ordinate to the new coordinate
(X Y) which sets the
position of the opposite corner
of the box.
UP, DOWN, LEFT. RIGHT
These four commands move
the whole hi-res screen by one
pixel in the direction specified.
Anything moved off the screen
will be lost.
SCROLL - Scrollsthe lower 24
lines (3 x 8) by eight lines upwards,
one at a time, and sets
the current print position to the
start of the bottom line. This
provides a three-character line
text window at the bottom of
the display for prompts and
messages.
COPY — This command,
believe it or not, copies the
whole hi-res screen to the ZX
printer.
To make this simple system
even simpler to use, all of the
graphics commands can be abbreviated
to the first two letters
so MOVE X Y DRAW A B
SCROLL comes out as MO X Y
DR A B SC.
The software
QS Defender occupies around
3K of machine code, and uses a
34 line display file which extends
from the top to the bottom
of the television screen. Up
to 84 fast-moving characters
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