IEEE Consumer Electronics Magazine - July 2015 - 65

still had black and white televisions. This also worked better
on monochrome monitors.
The final system had four main chips (Figure 7):
1) a 6507, a cost-reduced 6502 in a 28-pin package, losing
some functionality but saving US$0.50
2) a 6532, with 128 bytes of RAM, 16 I/O ports, and a programmable timer
3) the TIA with video, audio, and six extra specialized input ports
4) a 2048- or 4096-byte ROM on an inserted game cartridge.
gamE Program FloW
With this line buffer design, the game program flow was synchronized with the TV timing (Figure 8).
There were two general program execution phases:
▼ VBlank off: driving the TV display on a line-by-line basis in
what we called the kernel.
▼ VBlank on: processing console controls, collisions, and
other status to update the game status.
The program would have a way of representing the state of
the game:
▼ shape of the playfield
▼ location, orientation, and shape of two complex (8-bit
wide) moving objects
▼ location and orientation of three simple (1-bit) moving objects
▼ current settings for two sound channels
▼ other displays, e.g., score for each player.
During the vertical blank interval the program would:
▼ sample the controls from the user
▼ sample the collision registers
▼ determine changes to the state.
The program would then compute new values to display
and the locations. It would set up the zero page pointers that
the kernel would use to drive the display after the vertical
blank time ended. The program would poll the hardware timer
to know when to halt game state changes and enter kernel
execution. The efficiency of the 6502 to compute addresses into
the ROM graphics tables and other data structures on the fly
was crucial for the kernel.
IntroDuCtIon In 1977
We got the TIA working on the first try, and we prepared
to introduce it for Christmas of 1977. We assembled a system that was capable of displaying the first generation of
Atari arcade games. The launch titles [20] included Air-Sea
Battle (Kaplan), Basic Math (Palmer), Blackjack (Whitehead),
Combat (Decuir and Wagner), Indy 500 (Riddle), Starship
(Whitehead), Street Racer (Kaplan), Surround (Miller), and
Video Olympics (Decuir).
However, Atari management was justifiably concerned that
we would be lucky to succeed and luckier if we could be successful enough to replace the VCS with a better system before
our competitors did. We expected that the product might be
successful for maybe three years before we had to replace it.

ProDuCtIon HIstorY
We were surprised. The game designers turned out to be
much more creative than we hardware designers had anticipated. We made the hardware cheap to be economically
feasible in 1977. To do so, we moved functionality from the
hardware to the firmware. The game designers then took
advantage of the ability to "follow the beam" [21] and redefine the display on the fly [22].
More than 1,000 game cartridges were defined for this
game console system. The most important ports from arcade
games were Pac-Man, Missile Command, Space Invaders, and
Asteroids. The list of original games is very long; my highlight
set includes Adventure (Robinette) [23], Pitfall (Crane) [24],
River Raid (Shaw) [25], and Yars' Revenge (Warshaw) [26].
Production stared in July 1977, with 250,000 units that year.
Production stopped in 1989 (Atari VCS jr), with more than 30
million units shipped, after the Nintendo NES replaced the
Atari as the leading video game console. (The NES used a variant of the 6502 [27].)
What is even more interesting is that readers can still buy
these systems today, in 2015, 38 years later. The successor to
Atari sells Flashback products with a cost-reduced VCS system
and dozens of built-in games [28]. The Flashback 5.0, shown
in Figure 9, is shipped with wireless controllers and 92 games
included.
At Classic Games conferences, companies like AtariAge
[29] support new cartridge development. In 2010, 33 years
after the machine was first shipped, Ed Fries, a contributor to
the Microsoft X-Box game console, created Halo 2600 for the
Atari [30]. The graphics are a lot simpler, given the hardware,
but the essence of the game play survives.
EPIloguE: WHat WE lEarnED
It was clear that the unintended success was to put the definition of the display in the hands of the game designers,
who were smarter than we hardware designers expected.
Our conclusion was that our second system should not
simply be a bit map and a processor. We had created a platform for the art of others, and we planned to build on that
for the next system.
Given that lesson, we understood that we had to create
another platform. It had to be an efficient system with room
for the game designers to add value in ways at which we
could only guess. We had to allow them to follow the beam.
We did consult extensively with the game designers in hand.
We also thought that we should design a system that would
be open and easy to program. We wanted to attract game
designers and build a platform that attracted that new art. We
wanted to include features that made it easy to port existing
arcade games. The first wave of game designers had not yet
left to go into competition with Atari-we were not afraid of
them yet. In 1980, the first group left to form Activision, which
is still prosperous in 2015 [31]. Others followed.

july 2015

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