Star Tech Journal

STAR*TECH JOURNAL/SEPTEMBER 1983
12
A Regular Monthy Feature Technically Outlining a Newly Released Game
CINEMATRONICS' DRAGONS LAIR
By Mark "Bear" Attebery, Vending International Corp., San Juan Capistrano, CA
As all of you know, Dragon's Lair is the first laser disc
system to actually make it to the operator, and from the
initial reaction it has received from the players (both
verbally and moneywise ), we will be seeing a lot of laser
games in the future!
Although Dragon's Lair is the first on the market,
don't be deceived into thinking that the other guys were
caught with their eyes shut Sega already has units on test
and the scuttlebutt is that just about every other manufac-
turer has jumped on the bandwagon.
Since this is a new technology for our industry, it only
seems right that this totally new technology should be as
difficult to understand today as videos were to the pinball
mechanics when videos first came out ... right? Not right!
The major advantage ofCinematronics' unit is its simpli-
city! Besides the power supply (which happens to be
Cinematronics' old reliable that they have used since
197 8), player input, speakers, and an isolation transformer
which are standard on most games, you only have four
major components to learn about and two of them you will
probably say should have been included in the list of
standard parts above. The two major components that will
be new to you are the circuit panel assembly and, of
course, the disc player. The two units that vou will
recognize will be the digital (LED) display scoreboard
(which we all have worked on in the past) and the modified
Electrohome monitor.
The game's theme is ... A sorcerer has kidnapped a
beautiful (and I do mean BEAUTIFUL!) princess and is
holding her prisoner in an enchanted castle filled with dangerous, ingenious,
magical traps! Dirk ( our hero, the knight) must defeat these traps before he is
allowed to attempt rescuing the princess by killing a giant dragon ( with his
magical sword), and taking the key from around the dragon's neck to unlock
the princess' glass bubble cage.
The graphics are of a better quality than your Saturday morning
cartoons. In fact, they are on a par with Disney animated movies. An
interesting fact about this unit is that the quality of the animation alone is
enough to make it almost as much fun to watch as it is to play! This fact is not
only keeping the player's interest alive while he is waiting for" his turn", but
it is bringing people into the arcades ( and making players of them!) who
simply have had no interest in video games in the past.
System Hardware Operation
The Starcom system is controlled by a Z80A microprocessor. It runs at a
4Mhz clock rate. It can be reset manually by the reset switch located on the
main CPU board.
The system memory consists of RAM and EPROM. The RAM is on the
main CPU board. The EPROM is on the piggybacked board. The Z80A is
buffered from the rest of the system by uni- and bi-directional buffers.
Sounds are generated by a General Instruments sound chip A Y-3-89 IO.
Its output is mixed with the laser disc players audio out and then fed into two
LM383 audio amps.
The keyboard inputs are buffered by two 74LS244s. These inputs are
filtered to help eliminate noise.
The security device must be installed for the system to work properly.
Tampering with this device can be fatal to the system.
Game Adjustments
When the game is turned off, the DIP switches located on the main CPU
board may be used to select different options available as outlined in the
following tables. Changing the switch selection while the game is turned on
has no effect. Factory recommended settings are shown 'in the table. The
game is shipped with these settings.
DIP SWITCH (SW1) (Used as test port in playtest mode)
Switch #
Rec.
Function
_B_O_
on
Every 8th pass on demo has sound ( off).
The sound track in the demo mode is
only played every eighth time.
No sound at all (off = no sound).
B1
on
Off = unlimited life.
B2
on
Off = keyboard feedback enabled.
B3
off
Unused.
B4
on
B5
on
Unused.
B6
on
Unused.
Reserved for testing.
B7
on
DIP SWITCH (SW2)
Function
Switch#
Rec.
Credits/coin selection.
~
on
A1
on
A1 A1
On on = 2 coins/credit
Off on = 3 coins/credit
On off = 4 coins/credit
Difficulty level one/two (one = on).
A2
on
Playtest on/off (off = playtest).
A3
on
This is used only by the programmers.
Off = 2 credits always.
A4
on
A5
on
Three or five lives (3 = on)
Off= pay as you go.•
A6
on
Diagnostic on/off (off = diagnostics).
A7
on
I
•At the completion of the first third of the game and the second
third of the game, each, the player must insert an additional two
coins to continue play. Pay as you go can only be used with the 2 coins per credit
setting.
Diagnostics
The diagnostics is a series of tests performed on the system's hardware to
verify that the hardware is fully functional. The diagnostic routines are
initiated by having the dip switch set in position when the power is turned on.
The diagnostic software is resident in the Z80A game program EPROM.
RAM Test
Each RAM cell is loaded with 55H and then read to insure that all cells
retained the data. The RAM is then reloaded with OAAH. This inverts
every bit in every cell. The RAM is then read again to verify data retention.
If all cells are operating properly, the the diagnostics will proceed to the
EPROM check. If a bad cell is found, the system will display "RAM test
failed" on the monitor. The system will stay there until it receives a reset
EPROM Test
There are 5 SK-byte EPROMs within the system. The diagnostics caculates
each EPROM's checksum and then compares it to the prestored correct
checksum values. If all checksums verify, the diagnostics continues with the
security device test If an EPROM fails, the monitor will display "ROM
Test Failed" and will show the address location of the bad EPROM. The
address locations are given in the following table:
Checksum#:
Checksum 1:
Checksum 2:
Checksum 3:
Checksum 4:
Checksum 5:
Address Location
0FFF6H
0FFF8H
0FFFAH
0FFFCH
0FFFEH
EPROM Address
OOOOH-lFFFH
2000H-3FFFH
4000H-5FFFH
6000H-7FFFH
8000H-9FFFH
Continued on next page.