12
STAR*TECH JOURNAL/FEBRUARY 1983
A Regular Monthly Feature Technically Outlining a Newly Released Game
ATARI'S "POIE POSITION''
By Joe Connor, Active Amusement Co., Philadelphia, PA
The latest driving game to enter the market comes from
the company (Atari, licensed from Namco) that first
introduced driving games (GT-10) to the amusement
industry almost 10 years ago. "Pole Position" is being
met with great anticipation and hopes that it can top not
only Atari's own previous driving games ("Sprint II",
"Super Bug", and "Monte Carlo") but also two very
successful driving games manufactured by Sega -
" Monaco Grand Prix" and "Turbo". Like both of these
games, "Pole Position" includes some incredible graphics
and is available in an upright or sitdown cabinet.
Game action takes place at the "Fuji" Speedway in
Japan. The player drives a F ormula-1 race car, controlling
it with a steering wheel, two-position gear shifter, and
accelerator and brake pedals (brake pedal only used in
sitdown cabinet). If qualifying against the clock, the
player then races against the clock and other cars trying to
finish the race as fast as possible. Points are awarded for
passing cars, driving on the track, and finishing the race
with time remaining. Game play is perhaps the most
realistic of any driving game ever manufactured.
The steering is obviously the most critical control in
any driving game. In "Pole Position", the steering is
especially "natural-feeling" and responsive. When turning
through a curve, the front end of the car responds first,
turning semi-independently just like a real car. While
driving around the race course, objects on and around the
track appear almost exactly as they would if you were
viewing them from a speeding race car. Roadside bill-
boards ("Gravitar" needs the advertising a lot more than
"Centipede" or "Dig Dug") which can just barely be read
at full speed can easily be viewed by cruising up to them at slow speeds or stopping
in front of them (hardly the object of the game, but still a nice effect). Acceleration is
also semi-realistic by means of a SK pot instead of just a switch under the
accelerator pedal. All the outstanding graphics and realism have not been
accomplished without some variations in the electronics package. As mentioned
earlier, this is a licensed game (like "Dig Dug" and "Kangaroo"), so naturally the
board design would be slightly different than games Atari designs itself. "Pole
Position", however, is especially unique ( two independently powered logic boards,
RF cage}, and includes many new features never seen in previous Atari games.
DRIVING CONTROLS
Since "Pole Position" is a driving game, breaking it down into three areas that are
common to all driving games might be helpful. These would include steering,
acceleration, and shifting.
Steering- (See game manual Pages 3-10, Figures 3-5). Steering control, as usual,
is accomplished with the aid of an encoding wheel mounted under the steering
wheel. This encoding wheel breaks a beam of light which is directed at a photo-
sensitive transistor. There are two diodes and two transistors mounted inside a
packaged radial optic coupler. The CPU board receives information from this
coupler relating both the speed and direction of each turn of the steering wheel. The
coupler PCB is Atari Part Number AO35220-02. This is the same coupler board
used in "Centiped,e''. Keep in mind that this is an -02, not an -01 board. The -02
boards are pretested and they must provide adequate output voltage levels at certain
RPMs to be designated as -02 boards. Originally this was done to help cure the "my
'Centipede' sticks in the corners" problem. Fortunately, Atari also has made
available an -02 optic coupler (030369-02) that matches the -02 board. Previously
you could acquire an -02 board, but if the optic coupler went bad and you replaced
it, you wouldn't be sure if the new optic coupler fell within (-02) specifications. This
new coupler has mistakenly been printed 030369-01 in the steering wheel parts list,
when it actually is 030369-02. (See Atari "Pole Position" Modifications in this
issue of S*TJ, page 18.) The optic assemblies in Atari games used to be pretty
reliable. A few problems first developed when they were used in the" Football" trac
ball assembly. Not until "Centipede" did the whole mess with them really develop.
Fortunately, the problems with the couplers are much more noticeable when used
with a trac ball assembly. Since "Pole Position" is a driving game and uses a
steering wheel (as opposed to a trac ball assembly), you can be assured that there
probably won't be any more problems ~ith "Pole Position"
(probably less - the coupler is now a sealed unit) than
those experienced on previous Atari driving games like
"Sprint II".
The coupler board is connected via P52 (a 4-pin
connector) to the CPU board.
CPU Board (P20) Steering Coupler Board
Pin H
Pin 1 (Steering 2)
Pin Y
Pin 2 (+5 volts)
Pin Z
Pin 3 (Ground)
Pin 8
Pin 4 ( Steering 1)
On the logic board, the steering information 1s squared
and buffered by an MC4584 (SL) before entering a
custom chip in location 9K.
Testing/Maintenance - The steering can be checked
during the self-test procedure. While in test, the word
"steering" and a number to the right of it will appear on the
screen. As you rotate the wheel clockwise, this number
should increase; as you rotate the wheel counter-clockwise,
it should decrease. Any failure of this test would indicate a
bad coupler board or wiring problem. The steering
mechanism should be lubricated every six months. Atari
recommends a light film ofNyogel 779 or, ifnecessary, 3-
in-one oil for the bronze bearings and the two gears on the
steering shaft. For detailed information on lubricating and
assembling the steering mechanism, see the "Pole Position"
Game Manual.
Acceleration - ( See game manual Pages 3-14, Figures 3-
7). When the "gas" pedal is depressed, a spring and pulley
assembly located under the accelerator pedal turns the
shaft of a SK potentiometer. As the resistance of this pot
increases, so does the acceleration. The three wires from this pot are connected via
J25 (a 4-pin connector, 5-pin in a sitdown) directly to the CPU board.
Potentiometer
Green Wire ( centertap)
Black (ground)
Red (+5 volts)
CPU Board (P20)
Pin F
Pin P
Pin R
All acceleration information enters a 4066 ( analog switch, position 8K), directly on
the CPU board. The output of the 4066 is then fed to an analog to digital converter
(ADC0804, position SJ). This IC converts the analog acceleration into digital
information and feeds it directly onto the data bus, where it can be acted upon by the
microprocessor.
Testing/Maintenance - Like the steering, the accelerator can be checked during
self test. In the self-test mode, the word "accel" and a number (00) will appear on
the screen. As you press down the accelerator pedal, the number will increase from
00 to somewhere between 90 and AO. If this test fails, suspect a mechanical
problem in the foot pedal assembly or possibly a bad A-D converter on the CPU
board.
The only maintenance recommended for the accelerator is periodic ( 4 months)
lubrication. Spraying the pivot pin and surround area, the springs, cable and pulley
with dry teflon spray should be sufficient.
The accelerator assembly appears to be very straightforward in its design and
really should pose no mechanical or electrical problems. However, there is one
aspect which makes it quite unique and is very important to keep in mine whenever
troubleshooting or just powering the game up. You may have noticed various
warnings in the "Pole Position" Manual: "DO NOT DEPRESS THE ACCEL-
ERA TOR OR BRAKE PEDAL WHEN TURNING ON THE GAME OR
SWITCHING TO THE SELF-TEST MODE. THIS WILL CAUSE FAULTY
PROGRAM INITIALIZATION AND INCORRECT ACTION OF THE
PLAYER CONTROLS."
This advice is important because the game has been designea so that on power
up the logic board references the position of the accelerator pedal ( SK pot) and uses
this as the starting point for acceleration. Obviously the pedal should be fully
elevated or else the board will "think" that whatever position the pedal is in on
power up is the starting ("0" acceleration) point. Idealistically this is a good idea
(negating the effects of a worn or dirty pot), but in practicality causes problems. To