Page 1
USERGUIDE
FORTNE
BBC
Micro
Model
'B'
Version
Page 2
Page 3
CONTENTS
Para.
Para.
Para.
Para.
Para.
Para.
Para.
Para.
Para.
Para.
1
Welcome
Intro
2
Connecting
3
4 Software
Loading
5
Loading
6
7 Transferring
Specification
8
User
9
10
Port
Maintenance
Up
Description
and
running
and
running
to
disc
connections
the
Utilities
drawing
Software
program
Paintball
1
Page 4
I.
WELCOME
This booklet and the cassette tape that
goes with it will help you to get your
Tracker Ball working and show you how
versatile and accurate the Tracker Ball
in positioning the cursor on a video
display.
For the more advanced user, this booklet
contains technical information which
explains how the Tracker Ball works and
ways in which
Firstly check that the box contains the
following:
• Tracker Ball with inbuilt connecting
cable.
• Tape cassette containing the Utilities
program.
TO
THE
112
it
can be programmed.
TRACKER
is
BALL
Page 5
2. INTRODUalON
The function of the Tracker Ball is to act as
a pointing device to move the cursor on
the video display.
Tracker balls evolved from joysticks, and
are so accurate that the Tracker Ball is
now recognised as the ultimate device for
quick and precise control of a cursor.
The Marconi RB2/PC-1 Tracker Ball has
been designed for the BBC Micro Model
'B'
version and contains three user
assignable buttons which can replace
existing keyboard key functions or act as
additional keys specially assigned by the
user.
The tape cassette supplied with your
Tracker Ball provides a Utilities program
which allows you to run many of your
existing programs but using the Tracker Ball
instead of cursor keys, joysticks or
·mouse'. The tape also provides a
demonstration drawing program
Paintball.
To see how versatile and accurate your
Tracker Ball is follow the next few pages
of
the booklet.
Page 6
3.
CONNEOING-UP
As
a minimum you will need the following:
e BBC Micro Model 'B'
• Cassette player
or
• Monitor
• Tracker Ball
• Tape cassette
The booklets supplied with your BBC
Micro Model 'B' will tell you all you need to
know about connecting up the BBC Micro.
cassette player. disc drive unit and
monitor (or television set).
Before connecting up the Tracker Ball.
make
disconnected
television set
sure that the electrical supply is
or
switched off.
Connect
connector marked ·user port· on your
BBC
underneath the keyboard in the centre
position.
Switch on the electrical supply. You are
now
the Tracker Ball into the
Micro Model 'B'. This connector is
ready to load the software.
Page 7
4.
SORWARE
DESCRIPTION
Note: This software
Operating systems 1.0 and above.
Enclosed with the Tracker Ball
cassette tape, with programs to allow your
Tracker Ball to be used with your BBC
Model 'B' Microcomputer. The tape
titled SOFTBALL.
is
suitable for BBC
is
a
is
Side1
1 . A utilities program which assembles
machine code cursor control and
joystick simulation programs. It also
provides a utility to allow the user to
in
include a Tracker Ball facility
program.
2. A demonstration drawing program,
called Paintball, which allows the user
to create complex graphic displays
using the Tracker Ball.
his own
Side2
1 . A version
suitable for saving
2.
A slightly modified version of the
demonstration drawing program on
SIDE
1.
of
the utilities program
to
disc.
1.
Utilities Program
This allows the user to substitute Tracker
Ball
in
a) As cursor control
keys. This
Wordwise and
editing.
b)
As replacement for the joystick used
certain compatible games.
c) Finally, a specially written utility is
provided for inclusion
programs.
is
Cursor Control
TRACKER BALL
The cursor control option provides full
control over the editing cursor using the
Tracker Ball instead of the cursor keys.
This is useful for word processing, e.g.
conjunction with Wordwise. The program
also assigns the DELETE, RETURN and
COPY
functions to the three push buttons
on the Tracker Ball. Alternatively, the user
may assign his own choice of keys to
these three push buttons. The only keys
not permitted are ESCAPE, CAPS LOCK.
SHIFT LOCK. CONTROL, SHIFT and
BREAK.
place of cursor
particularly good with
in
general program
in
user-written
Utility-
in
in
Page 8
Joystick Simulation
Utility-
JOYSTICK
This routine is intended for use with those
games
and other programs which would
benefit from the use of Tracker Ball as an
alternative to a joystick. The routine also
allows a user-written joystick program to
have a Tracker Ball alternative by
including the BASIC ADVAL() function or
using OSBYTE & 80.
User written programs - DIRECT
A programmer who wishes to build the
Tracker Ball into his program would
normally assemble this utility and save to
or
tape.
It
disc
into his program when convenient.
is then ready to assemble
Which joystick programs will work
with RB2 Tracker Balls?
First, since the above utilities use 256
of
Bytes
necessary that any joystick program to be
run does not occupy the whole memory of
the BBC.
Second, the above utilities must not be
loaded into a memory location used by the
memory when loaded, it is
joystick program to be run. The utilities
program helps here by offering the user a
choice of memory locations likely to be
available. The correct choice is found by
In
most instances the &900 location
trial.
is suitable.
2. Demonstration Drawing Program
Paintball
Paintball is a versatile but user-friendly
package which allows the user to create
four-colour drawings with the aid of the
RB2
Tracker Ball. Both text and graphics
can
be fully mixed and the results can be
or
saved to tape
The package
to the use of a menu and the RB2 Tracker
Ball, which vastly speeds up cursor
positioning.
disc for future use.
is
very easy to use, thanks
Cursor Control
The
cursor controlled by the Tracker Ball
is central to Paintball. The cursor is used
for
positioning and drawing points and
also for helping to select options from the
menu which is on the right hand side of the
The
screen.
sole
input most
Tracker Ball functions as the
of
the time.
Page 9
Buttons
Text
The
ball
moves
the cursor and the left
hand
and
centre buttons are used
·select' buttons.
important.
co-ordinates
If a
from
displayed.
displayed.
When
of
shape
is being drawn the distance D
the
last point
For
The
right hand button is
it is pressed the X and Y
the cursor are displayed.
to
the cursor is
a circle
the
radius R is
as
Colours
Four
colours
any
time.
the bottom
of
the colour
the left hand
becomes
is displayed.
When
the
next
replaces the selected colour. A further
push
on
and
so on.
NOTE:
colour
are
allowed
The
colours
four
buttons
boxes
portion
the ·current' colour and the
the right hand portion is selected,
colour in a sequence
the
button selects the next colour
The
colour selected cannot be a
already on screen.
on
the screen at
are
accessed via
of
the menu. Each
is split into two.
is selected, that colour
of
When
four
'ON'
Text can be typed
any time. If the text is not over the menu
then it will be printed on the screen at the
cursor position.
The text can be positioned on the screen
by moving the Tracker Ball. Pressing a
·select' button freezes the text.
Text can
special compressed type which is only
available in upper case. The compressed
text is accessed by holding down the
CTRL key while typing.
be of the normal type
in
from the keyboard at
or
of a
Menu functions available
GRID:
superimposed
help
again
The GRID function should be used with
caution since grid points drawn over while
the function is on will reappear while the
function is switched off. See also section
6.
When
selected, a grid
on
the screen. This is to
with alignment. Selecting GRID
takes
the grid away.
of
points is
Page 10
SOLID: Circles, triangles and oblongs
will be drawn
selected, as well as the shape function.
Otherwise they will be drawn
in
solid if this function is
in
outline.
CIRCL: When selected, a circle may be
drawn by first defining its centre, then any
point on its circumference.
TRNGL: When selected, a triangle may
be drawn by defining three cursor points.
OBLNG: When selected, an oblong may
be drawn by defining two diagonal
corners.
LINE: When selected, a line may be
by
drawn
banding is employed for ease of use.
defining two points. Rubber
DRAW: When selected, the user may
draw
free-hand. This is achieved by
moving the ball, while holding down a
·select' button with the other hand.
It
Note:
background colour, that is, the colour
shown
is only possible to fill over the
'ON'
in
the bottom colour box.
CLEAR: This resets the menu and clears
the screen to the background colour.
LOAD: This will load a named drawing
from disc or tape on to the screen for
further use. See also section
SA
VE:
This
will
save a named drawing,
along with its colour palette to a disc or
tape for future use.
6.
USER: This function is left blank to allow
to
a programmer
choice, e.g. a screen dump routine. The
USER
function may be intercepted as a
procedure at line 6500 in PBALL 1 .
The result
standard unmodified system is merely to
reset the menu.
add a function of his own
of
selecting USER on the
FILL: After selection, an enclosed shape
may
be filled by positioning the cursor
inside the shape and pressing a ·select'
button. To stop filling, press ESCAPE key.
CAT: This is a catalogue function
available for disc systems only. When
selected, a catalogue of the disc contents
is displayed for three seconds.
Page 11
5.
LOADING
AND
RUNNING
THE
UTILITIES
SGnWARE
Programs
Tracker
loaded directly from tape
immediately. Where the program to be
run
sequence
be
First insert side 1
cassette player and rewind.
To load, type
RETURN and wait for the tape to load.
NOTE: If your machine is fitted
disc filing system or Econet, remember to
type *T. followed by RETURN.
Once loaded, the screen first displays an
explanation of the system.
Next, an initial menu option is offered:
1.
Proceed to UTILITIES
2. Pass straight to demonstration
drawing Paintball.
3.
Look at an EDIT DEMO. (Disc version
only)
written specifically to use
Ball, e.g. Paintball, may be
needs
the Utilities, the following
of
loading and running should
followed.
of
tape Softball into the
CH."",
followed by
or
disc and run
with
a
If UTILITIES is selected, the next menu
offers UTILITIES
1.
DIRECT
2.
JOYSTICK
3.
TBALL
4. HELP
as previously described.
Select your choice by moving the Tracker
Ball and pressing the Tracker Ball centre
button. HELP provides assistance. A brief
explanation
displayed.
If JOYSTICK is selected - follow the
sequence
summarised
of
the chosen utility is then
of
screen menu selections
below:-
Menu1 Asks if the joystick program
to run uses Joystick 1 ,
response:-
Menu2
Joystick 2
Asks which joystick
connection is required Acorn standard, reversed X
and Y axes etc. After a
response:-
or
both. After a
Page 12
Menu3
Asks the user
to
select the
memory location required for
the location of the Utility. After
a
response:-
TBALL
If
is selected:
Menu options are offered in a similar
way
to the joystick utility.
Menu4
Tells the user that the Utility is
now ready and offers the
choice:-
1 . RUN
CODE
if required to run
immediately
2. SAVE CODE to disc or tape
RESTART
3.
if required
A frequently used utility should be given a
file
number
or
tape.
To
RUN CODE simply press BREAK. A
tell-tale
appear
'BBC
MEDL-J
and saved separately on disc
MEDL
-J symbol will then
on the top of the screen next to
Computer'. The presence of this
sign whenever BREAK is
pressed is always an indication that the
Utility is present.
You are
now
ready to load the main
joystick program in the normal way.
Menu 1 Asks the user to select the
designation of t
1
Tracker Ball Buttons.
1.
DEFAULT KEYS (i.e. standard
DELETE, RETURN, COPY)
2. USER KEYS
If USER KEYS is selected press the
choice
of
keys you require to be
simulated by the given ball
movements. Note, while this screen
selection is present, DO
NOT
the Tracker Ball.
Menu 2 Offers choice of memory
location, as for JOYSTICK
Once the memory location has been
selected, proceed as for JOYSTICK.
MEDL-T
A
of
the utility.
symbol indicates the presence
,e
three
move
Page 13
If DIRECT is
selected:-
Loading the main program
Choice
Once this has been done proceed as for
JOYSTICK.
A
of the utility.
of
MEDL-D
memory location is offered.
symbol indicates the presence
Load and run all main programs as
normal, but use Tracker Ball instead of
Joystick or cursor keys.
Hints
1 . The main program may be run
normally without upsetting the utility.
Pressing BREAK
most programs will not usually affect
Only
CTRUBREAK
utility.
2. If the memory location chosen for the
utility won't allow the main program to
be run, start again, and try another
location.
3. Never try to load a utility into memory
when one is already there. Always
clear memory by pressing
BREAK.
4. In the final selection menu, if SAVE
CODE
is selected in error press
BREAK and start again.
or
SHIFT /BREAK on
will remove the
CTRU
it.
Page 14
6.
LOADING
AND
RUNNING
DUWING
PROGRAM
PAINTBALL
CAUTION: Before attempting to load this
program, always clear the
and
don't
CTRU
wait
forget
of
draw
memory by pressing
BREAK.
Insert
Side 1 of
Type
CH
tape
for the
NOTE: If your machine is fitted with a
disc filing system
to first type
When loaded the screen displays the
'Do
prompt
(Y
/N)'.
If you press Yes, the cassette
commences to load the main program
instructions. This is several screens of
text explaining
with Tracker Ball.
If you press No, the cassette loads the
screen menu and you are ready to
using the Tracker Ball.
Hints
1.
When FILLING if a colour 'leaks' then
press ESCAPE to stop filling.
cassette
'PBALL'
to load.
or
*T. (RETURN).
You require instructions
how
tape Softball.
(RETURN)
Econet,
to use the program
2.
Erasing. If a mistake is
erased by drawing solid oblongs
triangles in the background colour
the troubled area.
Unwanted grid dots left superimposed
on a coloured area
asfollows:-
Select
as
background
affected
dot::;
3.
LOAD
If this happens, an 'Enter filename ·
appears at the top of the screen. Enter
a
QQQ(RETURN). The screen then
displays LOAD Y
you type
menu. If you type Y by mistake, a load
onto tape
ESCAPE, to return to normal menu.
4. BREAK is pressed by mistake.
To
followed by RETURN.
area.
Select
or
LINE
for
or
SAVE
dummy
filename, e.g.
N screen returns to normal
or
disc
restore the menu type RUN
made
it can be
may
be removed,
colour, colour of
DRAW
for
row
of
dots.
selected by mistake.
/Nor
SAVE
Y /N. If
is attempted. Press
or
over
individual
Page 15
7.
TUIISFEIIUNG
Side 2
of
the Softball tape contains a
version of the Utilities and Paintball
suitable for transferring to disc.
To help you do this, a disc-making
program is included at the beginning of
the tape.
To load type *T. (RETURN)
CH.""
Then
Once the new disc is made it can be called
up by
CH." " INTRO"
TO
DISC
"(RETURN)
Page 16
8.
SPECIFICATION
The
Marconi AB2 Tracker Ball is
designed for desk top mounting and is
housed in an attractive plastic moulding
styled to match the modern office
environment.
The
Tracker Ball is operated either by the
fingers or by the palm of the hand and is
free to rotate in any direction without
limiting stops. The ball sits on two freely
rotating steel shafts at right angles to each
other
and a roller bearing forms a third
support point. The two shafts drive optical
encoders which produce trains of
electrical pulses in X and Y directions, the
number
of pulses produced being
proportional to the vector quantities
derived from the ball's movement. The
pulses are shaped internally such that the
final output of the Tracker Ball is 2 trains of
square wave pulses for each of the X and
Y directions. The phase relationship
between these pulses determines the
direction. This is clear from the output
waveforms.
In addition, the Marconi AB2 Tracker Ball
has three buttons which can have any
function assigned by the user.
The
AB2 Tracker Ball does not contain its
own
electrical supply. It requires only a 5
volt de supply for operation and it derives
of
this supply from the user port
the BBC
Micro Model 'B'.
Output Waveforms
x11v11UliuL..fLJ
X21Y2)
u-ui_n_n__r
Xl
!Yl
I Lead,ng means RIGHT (DOWN)
X1
IY1)
u-ui_n_n__r
X2
(Y2i
___n__ri_n.__s-
X2
IY2) Leading means LEFT (UP)
Page 17
Physical Characteristics
Length
Width
Height
Weight
Ball diameter
Ball colour
Body colour
Tracking force
Drive ratio
Buttons
Operating
temperature
Storage
temperature
200mm (7.87 in)
115mm (4.53 in)
70mm (2.76 in)
600gm (21.12oz)
57mm (2.25 in)
Brown
Ivory
30gm (1.06 oz)
Tangential force on
ball periphery
200 pulses
for 1 full ball
revolution
direction.
Three, each user
assignable.
Guaranteed life
7
10
button.
5°
±5%
in
X or Y
operations per
Cto
45° C
Page 18
Electrical Characteristics
Cable Length
Connector
Type
Input Power
Requirements
Square Wave
Outputs
Button
Outputs
1 metre (39.37 in)
20-Way connector
compatible with BBC
Micro User Port.
5Vdc 5% 60mA
max from user port
of
BBC Micro
Model 'B'.
'1
' and
when
TIL
TIL
is
Standard 5V
levels. Encoded
square wave
outputs are
quadrature coded
to provide
directional information.
Normally 5V
level. Output falls to
OV when button
pressed. The switch
outputs are normally logic
·o·
logic
pressed.
Page 19
9.
USER
PORT
CONNEmONs
10.
MAlffllWIQ
The Tracker Ball outputs are fed directly
into the user port with the port defined as
an input. The
in conjunction with PB3 and PB4 for
sensing pulses and determining the
direction
The connections
CB1
CB2
PBO
PB
1 Middle switch button
PB2 Right switch button
PB3 X2
PB4
PB5, PB6, PB7, not used
5V Power Connection
OV
CB
1 and CB2 lines are used
of
rotation of the ball.
are:-
X1
Y2
Left switch button
Y1
Power Connection.
An occasional clean and polish of the ball
is normally sufficient to keep the RB2
running smoothly.
In
the event of liquid spillage past the ball,
the inside of the RB2 should be dried out.
First remove the 4 screws holding the top
cover of the RB2.
cover and then the ball. Carefully dry all
parts with a non-fluffy cloth and
reassemble.
Next, remove the top
Page 20
Marconi
Electronic
Power Division
Carholme Road, Lincoln
Tel: (0522) 29992 Telex: 56163
Devices
LN1
1SG
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