Mike Matei / February 26th, 2018
James and Mike play Princess Rescue for Atari 2600
March 1, 2018 at 12:07 pm
The key to understanding how it works is understanding how low-level the joystick support actually is.
Games don’t ask the console “What’s the state of the button?”. The 2600 doesn’t have enough memory to afford that kind of abstraction. Instead, each game just checks “are we getting power on this wire?”
Each direction and each button gets a wire, and then the last two wires are 5-volt power and ground.
Because Atari wired up all of the pins on the connector, including the ones they don’t use, supporting the extra two buttons on a Genesis controller is done by having the game listen for signals that vintage games would have ignored.
More recent examples of that principle would be the various accessories which plug into the controller port on the SNES, such as the NTT Data Pad (a SNES controller with a numeric keyboard for betting on Japanese horse racing) and the Turbo File Twin (a Japanese peripheral for adding more save slots to compatible ASCIIsoft games via the controller port.)
As for the TAC-2, there were something like a dozen machines which used that same joystick port back in the day.
If the two buttons are wired separately and the Atari just interprets them as the same thing, then it was designed for one of the other machines with more than one button on the official controller.
If the two buttons are wired together, then they probably reused the plastic moulds originally created for a stick made for two-button machines, tweaked the wiring, and then marketed the result as an ambidextrous design.
March 3, 2018 at 1:18 am
Interesting detail I just learned in this vein today: Electrically, SNES controllers are NES controllers with extra buttons and you can swap out the plug on a SNES controller, plug it into an NES, and it’ll work.
(The difference being that, unlike the 2600 design, the SNES and NES don’t have one pin for each button. Instead, the controller has a chip called a shift register that lets the console send a “start query” signal and then keep sending “next button” until the list of buttons is exhausted. The SNES controller just has a longer list than the NES.)
Nintendo even wired things up inside the SNES controller so that A and B on the NES get mapped to B and Y on the SNES controller.
March 5, 2018 at 3:59 pm
Cool tech data man! thanks for an insightful comment truly!
March 9, 2018 at 1:01 pm
The Atari Junior (budget 2600) controllers had two buttons. So maybe it would’ve worked with those.
March 11, 2018 at 4:28 am
I play this on the original hardware with the regular one button controller. Fireballsa re shot either with up+button or down+button. It is described in the manual and always work. No magic no special controller.
March 11, 2018 at 5:18 am
Well, just checked the manual. It is just UP
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