Marconi RB2/PC-1 User manual
USERGUIDE
FORTNE
BBC
Micro
Model
'B'
Version
CONTENTS
Para.
1
Welcome
Para.
2
Intro
Para.
3
Connecting
Up
Para.
4 Software
Description
Para.
5
Loading
and
running
the
Utilities
Software
Para.
6
Loading
and
running
drawing
program
Paintball
1
Para.
7 Transferring
to
disc
Para.
8
Specification
Para.
9 User
Port
connections
Para.
10
Maintenance
I.
WELCOME
TO
THE
112
TRACKER
BALL
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
is
in positioning the cursor on a video
display.
Forthe more advanced user, this booklet
contains technical information which
explains how the Tracker Ball works and
ways in which
it
can be programmed.
Firstly check that the box contains the
following:
• Tracker Ball with inbuilt connecting
cable.
• Tape cassette containing the Utilities
program.
2. INTRODUalON
Thefunction ofthe TrackerBall is to actas
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 ofa cursor.
The Marconi RB2/PC-1 TrackerBall has
been designed for the BBC Micro Model
'B'
version and contains three user
assignable buttons which can replace
existing keyboard key functions oract 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 ofyour
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.
3.
CONNEOING-UP
As
a minimum you will needthefollowing:
e BBC Micro Model 'B'
• Cassette player
• Monitor
or
television set
• TrackerBall
• Tape cassette
The booklets supplied with your BBC
Micro Model 'B' will tell you all you needto
knowaboutconnecting up the BBCMicro.
cassette player. disc drive unit and
monitor (or television set).
Before connecting up the Tracker Ball.
make
sure that the electrical supply is
disconnected
or
switched off.
Connect
the Tracker Ball into the
connector marked ·user port· on your
BBC
Micro Model 'B'. This connector is
underneath the keyboard in the centre
position.
Switch on the electrical supply. You are
now
ready to load the software.
4.
SORWARE
DESCRIPTION
Note: This software
is
suitable for BBC
Operating systems 1.0 and above.
Enclosed with the Tracker Ball
is
a
cassettetape, with programstoallow your
Tracker Ball to beused with your BBC
Model 'B' Microcomputer. The tape
is
titled SOFTBALL.
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
includeaTrackerBall facility
in
hisown
program.
2. A demonstration drawing program,
called Paintball, which allows the user
to create complex graphic displays
using the Tracker Ball.
Side2
1. A version
of
the utilities program
suitable for saving
to
disc.
2.
A slightly modified version ofthe
demonstration drawing program on
SIDE
1.
1.
Utilities Program
This allows the userto substitute Tracker
Ball
a) As cursorcontrol
in
place of cursor
keys. This
is
particularly good with
Wordwise and
in
general program
editing.
b)
As replacementforthe joystickused
in
certain compatible games.
c) Finally, a specially written utility is
provided for inclusion
in
user-written
programs.
Cursor Control
Utility-
TRACKER BALL
The cursor control option provides full
control overthe editing cursor using the
Tracker Ball instead ofthe cursor keys.
This is useful for word processing, e.g.
in
conjunction with Wordwise. The program
also assigns the DELETE, RETURN and
COPY
functionstothe three push buttons
on theTrackerBall. Alternatively, the user
may assign his own choice of keys to
these three push buttons. The only keys
notpermitted are ESCAPE, CAPS LOCK.
SHIFT LOCK. CONTROL, SHIFTand
BREAK.
Joystick Simulation
Utility-
JOYSTICK
This routine is intended for use with those
games
and otherprograms which would
benefit from the use ofTracker 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.
Userwritten programs -DIRECT
A programmerwho wishes to build the
Tracker Ball into his program would
normally assemble this utility and save to
disc
or
tape.
It
is then ready to assemble
into his program when convenient.
Which joystick programs will work
with RB2 Tracker Balls?
First, since the above utilities use 256
Bytes
of
memory when loaded, it is
necessarythatanyjoystickprogram tobe
run doesnotoccupythewhole memoryof
the BBC.
Second, the above utilities must not be
loaded into amemorylocationused bythe
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
trial.
In
most instances the &900 location
is suitable.
2. Demonstration Drawing Program
Paintball
Paintball is a versatile but user-friendly
package which allows the usertocreate
four-colour drawings with the aid of the
RB2
TrackerBall. Both text and graphics
can
be fully mixed and the results can be
saved to tape
or
discfor future use.
The package
is
very easy to use, thanks
to the use ofamenuandthe RB2 Tracker
Ball, which vastly speeds up cursor
positioning.
Cursor Control
The
cursorcontrolled 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
menuwhich is on the right handsideofthe
screen.
The
TrackerBall functions as the
sole
input most
of
the time.
Buttons
The
ball
moves
the cursorand the left
hand
and
centre buttons are used
as
·select' buttons.
The
right hand button is
important.
When
it is pressed the X and Y
co-ordinates
of
the cursor are displayed.
If a
shape
is being drawn the distance D
from
the
lastpoint
to
the cursor is
displayed.
For
a circle
the
radius R is
displayed.
Colours
Four
colours
are
allowed
on
the screen at
any
time.
The
colours
are
accessed via
the bottom
four
buttons
of
the menu. Each
of
the colour
boxes
is split into two.
When
the left hand
portion
is selected, that colour
becomes
the ·current' colourandthe
'ON'
is displayed.
When
the right hand portion is selected,
the
next
colour in a sequence
of
four
replaces the selected colour. A further
push
on
the
button selectsthe nextcolour
and
so on.
NOTE:
The
colour selected cannot be a
colour
already on screen.
Text
Text can be typed
in
from the keyboard at
any time. If the text is not overthe menu
then it will be printed on the screen at the
cursorposition.
The text can be positioned on the screen
by moving the Tracker Ball. Pressing a
·select' button freezes the text.
Text can be ofthe normal type
or
of a
special compressed type which is only
available in uppercase. The compressed
text is accessed by holding down the
CTRL key while typing.
Menu functions available
GRID:
When
selected, a grid
of
points is
superimposed
on
the screen. This is to
help
with alignment. Selecting GRID
again
takes
the grid away.
The GRID function should be used with
caution sincegrid pointsdrawnoverwhile
the function is on will reappearwhile the
function is switched off. See also section
6.
SOLID: Circles, triangles and oblongs
will be drawn
in
solid if this function is
selected, as well as the shape function.
Otherwise they will be drawn
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
drawn
by
defining two points. Rubber
banding is employed for ease ofuse.
DRAW: When selected, the usermay
draw
free-hand. This is achieved by
moving the ball, while holding down a
·select' button with the other hand.
FILL: After selection, an enclosed shape
may
be filled by positioning the cursor
inside the shape and pressing a ·select'
button. To stopfilling, press ESCAPE key.
Note:
It
is only possible to fill overthe
background colour, that is, the colour
shown
'ON'
in
the bottom colour box.
CLEAR: This resetsthe 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
6.
SA
VE:
This
will
save a named drawing,
along with its colour palette to a disc or
tape for future use.
USER: This function is left blank to allow
a programmer
to
add afunction ofhisown
choice, e.g. a screen dump routine. The
USER
function may be intercepted as a
procedure at line 6500 in PBALL 1.
The result
of
selecting USER on the
standard unmodified system is merely to
reset the menu.
CAT: This is a catalogue function
available for disc systems only. When
selected, a catalogue ofthe disccontents
is displayed for three seconds.
5.
LOADING
AND
RUNNING
THE
UTILITIES
SGnWARE
Programs
written specifically to use
Tracker
Ball, e.g. Paintball, maybe
loaded directlyfrom tape
or
disc and run
immediately. Where the program to be
run
needs
the Utilities, the following
sequence
of
loading and running should
be
followed.
First insert side 1
of
tape Softball into the
cassette player and rewind.
To load, type
CH."",
followed by
RETURN and wait for the tape to load.
NOTE: If your machine is fitted
with
a
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 straightto demonstration
drawing Paintball.
3.
Look at an EDIT DEMO. (Disc version
only)
If UTILITIES is selected, the next menu
offers UTILITIES
1.
DIRECT
2.
JOYSTICK
3.
TBALL
4. HELP
as previously described.
Select yourchoice by moving the Tracker
Ball and pressing the TrackerBall centre
button. HELPprovidesassistance. A brief
explanation
of
the chosen utility is then
displayed.
IfJOYSTICK is selected -follow the
sequence
of
screen menu selections
summarised
below:-
Menu1 Asks if the joystick program
to run usesJoystick 1,
Joystick2
or
both. After a
response:-
Menu2 Asks which joystick
connection is required -
Acorn standard, reversed X
and Y axes etc. After a
response:-
Menu3
Menu4
Asks the user
to
select the
memory location required for
the locationof the Utility. After
a
response:-
Tellsthe userthat the Utilityis
now ready and offers the
choice:-
1. RUN
CODE
ifrequired to run
immediately
2. SAVE CODE to discor tape
3.
RESTART
if required
A frequently used utilityshould begiven a
file
number
and saved separately on disc
or
tape.
To
RUN CODE simply press BREAK. A
tell-tale
MEDL
-J symbol will then
appear
on the top ofthe screen next to
'BBC
Computer'. The presenceofthis
MEDL-J
sign whenever BREAK is
pressed is always an indication thatthe
Utility is present.
You are
now
ready to load the main
joystick program in the normal way.
If
TBALL
is selected:
Menu options are offered in a similar
way
to the joystick utility.
Menu 1 Asks the userto selectthe
designation of t1
,e
three
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
move
the Tracker Ball.
Menu 2 Offers choice ofmemory
location, as forJOYSTICK
Once the memory location has been
selected, proceed as for JOYSTICK.
A
MEDL-T
symbol indicatesthepresence
of
the utility.
If DIRECTis
selected:-
Choice
of
memory location is offered.
Once this has been done proceed as for
JOYSTICK.
A
MEDL-D
symbol indicatesthepresence
of the utility.
Loading the main program
Load and run all main programs as
normal, but useTrackerBall instead of
Joystick orcursor keys.
Hints
1. The main program may be run
normally without upsetting the utility.
PressingBREAK
or
SHIFT/BREAKon
mostprogramswill notusuallyaffect
it.
Only
CTRUBREAK
will remove the
utility.
2. If the memory location chosen for the
utility won't allow the main program to
be run, startagain, and try another
location.
3. Nevertry to load a utility into memory
when one is already there. Always
clear memory by pressing
CTRU
BREAK.
4. In the final selection menu, if SAVE
CODE
is selected in errorpress
BREAK and start again.
6.
LOADING
AND
RUNNING
DUWING
PROGRAM
PAINTBALL
CAUTION: Beforeattemptingto load this
program, always clear the
memory by pressing
CTRU
BREAK.
Insert
Side
1
of
cassette
tape Softball.
Type
CH
'PBALL'
(RETURN)
and
wait
for the
tape
to load.
NOTE: If your machine is fitted with a
disc filing system
or
Econet,
don't
forget
to first type *T. (RETURN).
When loaded the screen displays the
prompt
'Do
You require instructions
(Y
/N)'.
If you press Yes, the cassette
commences to load the main program
of
instructions. This is several screens of
text explaining
how
to use the program
with Tracker Ball.
If you press No, the cassette loads the
screen menu and you are ready to
draw
using the Tracker Ball.
Hints
1.
When FILLING if a colour 'leaks' then
press ESCAPE to stop filling.
2.
Erasing. If a mistake is
made
it can be
erased by drawing solid oblongs
or
triangles in the backgroundcolour
over
the troubled area.
Unwanted grid dots leftsuperimposed
on a coloured area
may
be removed,
asfollows:-
Select
as
background
colour, colourof
affected
area.
Select
DRAW
for
individual
dot::;
or
LINE
for
row
of
dots.
3.
LOAD
or
SAVE
selected by mistake.
If this happens, an 'Enterfilename·
appears at the top of the screen. Enter
a
dummy
filename, e.g.
QQQ(RETURN). The screen then
displays LOAD Y
/Nor
SAVE
Y/N. If
you type N screen returns to normal
menu. If you type Y by mistake, a load
onto tape
or
disc
is attempted. Press
ESCAPE, to return to normal menu.
4. BREAK is pressed by mistake.
To
restore the menu type RUN
followed by RETURN.
7.
TUIISFEIIUNG
TO
DISC
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)
Then
CH.""
Oncethe newdiscis madeitcan be called
up by
CH."
"
INTRO"
"(RETURN)
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 eitherby the
fingers orbythe palm ofthe hand and is
free to rotate in any direction without
limiting stops. The ball sits on two freely
rotating steel shaftsatrightanglestoeach
other
and a roller bearing forms a third
supportpoint. Thetwoshaftsdriveoptical
encoders which produce trains of
electricalpulses in X and Ydirections, the
number
ofpulses produced being
proportional to the vector quantities
derived from the ball's movement. The
pulsesareshapedinternallysuchthatthe
final outputoftheTrackerBall is2 trainsof
square wave pulses for each ofthe X and
Y directions. The phase relationship
between these pulsesdetermines 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
this supply from the userport
of
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)
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
±5%
for 1full ball
revolution
in
X or Y
direction.
Three, each user
assignable.
Guaranteed life
107 operations per
button.
5°
Cto
45° C
Electrical Characteristics
Cable Length
Connector
Type
Input Power
Requirements
Square Wave
Outputs
Button
Outputs
1metre (39.37 in)
20-Way connector
compatible with BBC
Micro UserPort.
5Vdc 5% 60mA
max from user port
of
BBC Micro
Model 'B'.
Standard 5V
TIL
levels. Encoded
square wave
outputs are
quadrature coded
to provide
directional inform-
ation.
Normally 5V
TIL
level. Output falls to
OV when button
is
pressed. The switch
outputs are norm-
ally logic
'1
' and
logic
·o·
when
pressed.
9.
USER
PORT
CONNEmONs
10.
MAlffllWIQ
The Tracker Ball outputs are fed directly
into the userport with the port defined as
an input. The
CB
1andCB2linesareused
in conjunction with PB3 and PB4 for
sensing pulses and determiningthe
direction
of
rotation ofthe ball.
The connections
are:-
CB1
X1
CB2
Y2
PBO
Leftswitch button
PB
1 Middle switch button
PB2 Right switch button
PB3 X2
PB4
Y1
PB5, PB6, PB7, notused
5V PowerConnection
OV
PowerConnection.
An occasional clean and polish ofthe ball
is normally sufficient to keep the RB2
running smoothly.
In
theeventofliquid spillagepastthe ball,
the inside of the RB2 should be dried out.
First remove the 4 screws holding the top
coverofthe RB2. Next, remove the top
cover and then the ball. Carefully dry all
parts with a non-fluffy cloth and
reassemble.
Marconi
Electronic
Devices
PowerDivision
Carholme Road, Lincoln
LN1
1SG
Tel: (0522) 29992 Telex: 56163
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