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Control Pad (Mega Drive)From Sega Retro
The Sega Mega Drive Control Pad (コントロールパッド) is the official controller of the Sega Mega Drive (or Sega Genesis in North America). Three button controllers are known officially as Control Pads in both North America and Europe, and SJ-3500s in Japan (following a system set up by the SG-1000). There are many "updates" and alternatives to this controller, the most notable being the Six Button Control Pad. This article covers only the basic three button variants. Mega Drive control pads are the logical progression from Master System control pads. Copying a system set up by Nintendo, the three button Mega Drive control pad adds, as the name suggests, an extra face button (or "Trigger" as it was initially called), Mega Drive controllers are notable for being one of the first control pads to be ergonomically designed for the user's hands. Though improvements were made in the coming years, previous systems had cornered edges with their controllers, meaning they were often uncomfortable to hold after several hours of play. The Mega Drive controller is rounded, and has its buttons placed in easier to reach positions.
VariationsControl pads remained mostly the same across regions, but the colouring can determine the region and revision of the accessory. JapanSJ-3500The first controller for the Sega Mega Drive, released in 1988. The
North AmericaSega Genesis Control Pad (Model No. 1650)Initial Sega Genesis three-button controllers had a white
Sega Genesis Control Pad (v2) (Model No. 1650)As the original Genesis was revised during the early 1990s, so were the controllers. The arrows were changed to white and the text was left black. The text "TRIGGER" was moved below the three buttons, and extra labels for Early versions of this controller used the same internals as the original design, but later models have an improved D-Pad mechanism, employing a metal ball-bearing for the pad to rock on. This prevented the wear which plagued the original design, which used a plastic nub for the rocking motion and would eventually wear down with frequent use. A minor addition is a little plastic lump on the
Sega Genesis Control Pad (v3) (Model No. 1650)Though this controller appears to be identical to the above, it once again has an updated D-pad. This was the first iteration of Sega's two-piece D-pad mechanism, used in every official subsequent controller up to and including the Sega Saturn's. Rather than providing the rocking motion by a plastic nub or ball-bearing, there is a molded dome underneath the outside half of the D-pad which allows the D-pad to glide smoothly in a circle. This design was also plagued with wear like the first model, eventually resulting in all four directions being able to be pressed simultaneously.
EuropeSega Mega Drive Control PadAlmost identical to the second Sega Genesis three-button gamepad, the first European Mega Drive controller sports a white
Sega Mega Drive Control Pad (revised)Later revisions of the Mega Drive controller retain the white
Sega Mega Drive Control Pad IIThis revised version of the original Mega Drive controller was released with the revised Sega Mega Drive II, with the main change being a red BrazilAsiaSouth KoreaSuper Aladdin Boy Control PadThe control pad that debuted along with Korea's Super Aladdin Boy is very similar to the first Japanese model. It contains a blue Technical InformationThe chip inside the control pad is a 74HC157. This is a high-speed CMOS quad 2-line to 1-line multiplexer. Basically, how this works is there are two inputs ( A and B ) for every output ( Y ). There are four groups like this. There is one select signal for the whole chip. When the select signal is low, the output ( Y ) is the same as input A. When the select signal is high, the output Y is the same as input B. The pinout for the chip is as follows:
All the controls are done with switches. Up is a switch, Down is a switch, etc. Now, I will be referring to the output of these switches later on. The output is usually high when the switch isn't pressed. When the button is pushed, the output goes low. This is accomplished by connecting the output to +5V through a 10k resistor. The button is then attached between the output and ground. It looks like this: +5V -----/\/\/------+--------- Output
10k |
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Ground -----/ -------+
button
(normally open)
The line numbers are determined as follows, looking straight at the plug on the front of the Genesis the numbers are: 1 2 3 4 5 6 7 8 9
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