Six Button Control Pad (Mega Drive)

Six Button Control Pad
Made for: Sega Mega Drive
Manufacturer: Sega
Release Date RRP Code

The Sega Mega Drive Six Button Control Pad became the de facto controller for the Sega Mega Drive, replacing the standard Control Pad internationally around 1993/1994. It is officially known as the 6 Button Arcade Pad in North America and the Fighting Pad 6B (ファイティングパッド6B) in Japan.

There are two main types of Six Button Control Pad, a smaller model originally intended for Japan, and a larger one intended for the west. The differences in size are due to a perception that the Japanese and people living in similar Asian countries have genetically smaller hands - it is an idea that passed through to the Sega Saturn and even to the Xbox before the realisation it might have been easier to produce one single pad for all regions. Indeed the larger variant was phased out by the end of the decade to cut costs and the Japanese variant would replace it worldwide.

The Six Button Control Pad is functionally identical to the previous pad but features three extra face buttons (or "triggers"); , and , placed above , and . The  START  button was moved to the centre of the pad, similar to Nintendo's set of controllers.

In most regions the Six Button Control Pad was released with Street Fighter II': Special Champion Edition which made use of the six-button layout. Though the game had been released on the Super Nintendo, it had to assign moves to the and buttons - the Mega Drive version is therefore more analogous to the original arcade version (and also means a separate arcade stick does not necessarily need to be purchased).

Some games do not function with the six button controller. To fix this situation, Sega added a  MODE  button on the top right of the controller. If held while the system is booting, the controller will revert back to a three button pad. Many six button games make use of the  MODE  button within play, bringing the total number of buttons to eight (plus a D-Pad). The Super Nintendo also has eight buttons, meaning porting games between the two consoles was made much easier.

There are some minor aesthetic differences between models. Japanese control pads have blue  START  buttons, PAL models have red ones, and North America has grey ones.

The six button control pad would be used as a basis for the Sega Saturn Control Pad, though the MODE button would be scrapped in favour of an extra two shoulder buttons, and .

Technical Information

In order to maintain backwards-compatibility with existing games, the 6-button gamepad acts the same as the 3-button if the controller inputs are read by the program a maximum of four times per frame. Reading the 3-button gamepad takes two cycles (once with TH=1 to read Up, Down, Left, Right, B, and C; and once with TH=0 to read A and Start), and the 6-button gamepad allows this to occur twice. It then reports the state of the extra buttons when the TH line is changed after the fourth cycle.

The full controller state is read in 8 cycles:

Cycle	TH out	TR in	TL in	D3 in	D2 in	D1 in	D0 in
1	HI	C	B	Right	Left	Down	Up
2	LO	Start	A	0	0	Down	Up
3	HI	C	B	Right	Left	Down	Up
4	LO	Start	A	0	0	Down	Up
5	HI	C	B	Right	Left	Down	Up
6	LO	Start	A	0	0	0	0
7	HI	C	B	Mode	X	Y	Z
8	LO	Start	A	---	---	---	---

Note: For the 8th cycle, '---' indicates "don't care". These values are all 1 on the 6-button controller, but may be mapped to other buttons on third-party controllers. Software expecting 6-button controllers should simply ignore these values. (6-button detection should be done on the 6th cycle, which presents four 0's on the D lines.)

The controller's internal counter automatically resets after the eighth cycle. It also resets if it doesn't detect a rising-edge (0 to 1) transition on the TH line within 1.5 ms, which ensures that most games that don't support the extra buttons won't read them accidentally.

Some games incorrectly read the controller more than twice per frame, which may cause them to read the wrong set of buttons. If the Mode button is held in while starting the Mega Drive console, the 6-button gamepad will disable the extra buttons and act identically to a 3-button gamepad. (That is, the controller's internal counter will reset after the first two cycles instead of after eight cycles.)

Incompatible Games

note: this list is incomplete

• Forgotten Worlds (reads controllers too quickly for the pad to keep up — there is no delay between setting TH and reading the new values, and apparently regular controllers are fast enough to handle this, but not the 6-button)

Games Requiring 3-Button Mode

note: this list is empty, please help

• Arch Rivals
• Golden Axe II
• Ms. Pac-Man

King of the Monsters requires an abnormally long press of the mode button in order to work.

Mode Button

Though the mode button is officially used on a six button control pad to switch between six button and three button modes, many developers utilised it in-game as an extra button for gameplay. In many situations the mode button's usage is kept hidden from the player by not being listed in manuals, thus its use is not widely documented.

List of Games which use the Mode Button

• Aerobiz Supersonic
• After Burner Complete
• Batman Forever
• Doom
• Dragon Ball Z: Buyuu Retsuden
• Fatal Fury 2
• The Lost Vikings
• Nightmare Circus
• Star Wars Arcade
• The Story of Thor
• TechnoClash

Gallery

• 

  US model

• 

  EU model

• 

  JP model

Promotional Material

• 6ButtonControllers MD US PrintAdvert.jpg

  US print advert

• 1994 02 - Mandos Mega Drive.jpg

  ES print advert

Physical Scans

Mega Drive, US
Cover

Mega Drive, US (newer)
Cover

Mega Drive, US (Sega Club)
Cover

Mega Drive, EU
Cover

Mega Drive, JP
Cover

Mega Drive, BR
Cover

Mega Drive, BR (Master System branding)
Cover

Mega Drive, BR (grey)
Cover

Mega Drive, CA
Cover

External Links

• Sega of Japan catalogue page (Japanese)