Difference between revisions of "Control Pad (Mega Drive)"

From Sega Retro

(→‎6-button gamepads: Clarified 8th cycle of 6-button protocol.)
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{{AccessoryBob
Over the span of the [[Sega Mega Drive]]'s lifecycle, [[Sega]] released eight different types of '''Sega Mega Drive gamepads''' across its three main regions--[[NTSC]], [[PAL]] and NTSC-J.  
+
| accessoryimage=Pad MD JP I.jpg
 +
| imgwidth=260
 +
| title=Control Pad
 +
| maker=[[Sega]]
 +
| madefor=[[Sega Mega Drive]]
 +
| releases={{releasesMD
 +
| md_date_jp=1988
 +
| md_code_jp=SJ-3500
 +
| md_rrp_jp=2,000{{ref|http://sega.jp/fb/segahard/md/pad.html}}
 +
| md_date_eu=1990
 +
| md_code_eu=
 +
| md_rrp_uk=14.99{{fileref|SegaForce UK 02.pdf|page=65}}
 +
| md_date_us=1989
 +
| md_code_us=MK-1650
 +
| md_date_ca=1989
 +
| md_code_ca=1650-22
 +
}}
 +
}}
 +
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 (Mega Drive)|Six Button Control Pad]]. This article covers only the basic three button variants.  
  
==Types of official gamepads==
+
Mega Drive control pads are the logical progression from [[Control Pad (Master System)|Master System control pads]], replacing {{1}} and {{2}} with {{A}} and {{B}} respectively, while adding an extra two face buttons, {{C}} and {{Start}} to bring the total number of buttons to four. Also featured is a circular D-Pad, designed to allow for movements in eight directions. Unlike [[Nintendo]]'s systems, the buttons (or "triggers" as they were initially called) are arranged in alphabetical order from left to right, a practise which would continue not only with future Sega consoles, but would inspire the controllers of the Neo Geo, 3DO and [[Xbox]] lines.
===Japan===
+
 
{|class="prettytable"
+
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.
!Picture||Description
+
 
|-
+
==Variations==
|[[Image:Pad MD JP I.jpg|150px]]
+
Control pads remained mostly the same across regions, but the colouring can determine the region and revision of the accessory. A minor addition added in the early 1990s is a little plastic lump on the {{B}} button, presumably to help users recognise where their right hand thumb was.
|valign="top"|'''Sega Mega Drive Gamepad, JP Type I''': Again, the Japanese version of the Sega Mega Drive gamepad is very much like the controllers released in the other two territories, though it has some distinct coloring differences: the {{A}}, {{B}} and {{C}} buttons are printed in red lettering instead of white, and the {{start}} button is blue. The text at the top of the controller reads "Computer Video Game Control Pad."
+
 
|-
+
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 prevents wear which plagues the original design, which uses a plastic nub for the rocking motion and will eventually wear down with frequent use. Later versions employ a D-Pad with a two-piece fulcrum design as seen on the Six Button Control Pad and all Sega Saturn pads.
|[[Image:Pad MD JP II.jpg|150px]]
+
 
|valign="top"|'''JP MegaDrive 6-button pad, aka Sega Club 6 button Jr''': This is the Japanese 6-button controller.  It is noticeably smaller than the standard North American and European model.  The blue Start button matches the color scheme of the Japanese console.  Of note, its buttons were lettered in a serif style, unlike the sans-serif used previously... this font would be used again on the Sega Saturn controllers.  Due to the smaller size, the controller was also offered in North America through the "Sega Club" as it was well-suited for kids' smaller hands. Sega Club was a program created by Sega of America to offer parents information about upcoming kid-friendly games. Sega Club was also responsible for "edutainment" titles and games with light difficulty for young gamers; Ecco Jr was one such title. 2-Piece D-Pad
+
<!-- rewrite
|}
+
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. -->
===North America===
 
{|class="prettytable"
 
!Picture||Description
 
|-
 
|[[Image:Pad_gen_v1.jpg|150px]]
 
|valign="top"|'''Sega Genesis Gamepad v1 "Model No. 1650"''': This is the first version of the NTSC gamepad for the Sega Genesis. It features three buttons—{{A}}, {{B}} and {{C}}—and has a white {{start}} button.  The arrows around the D-Pad are red, along with the indented label on each button, and the "Genesis" logo is two-toned; this color scheme matches that of the original Genesis.  
 
|-
 
|[[Image:Pad MD Gen.jpg|150px]]
 
|valign="top"|'''Sega Genesis Gamepad v2 "Model No. 1650"''': This is the second version of the NTSC gamepad for the Sega Genesis. It features three buttons—{{A}}, {{B}} and {{C}}—and has a white {{start}} button.  The red color has been dropped to match the updated "Genesis II" console design and color scheme.  It has 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.
 
|-
 
|[[Image:Pad_gen_v3.jpg|150px]]
 
|valign="top"|'''Sega Genesis Gamepad v3 "Model No. 1650"''': This is the third version of the NTSC gamepad for the Sega Genesis. It features three buttons—{{A}}, {{B}} and {{C}}—and has a white {{start}} button.  It maintains the all-white color scheme of the previous revision, but again has an updated D-Pad.  This was the first iteration of Sega's 2-Piece D-Pad mechanism, used in every official subsequent Sega Saturn controller.  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.
 
|-
 
|[[Image:Pad MD Gen3.jpg|150px]]
 
|valign="top"|'''Sega Genesis 6-Button Gamepad "MK-1653"''': Following the success of [[arcade]]-to-Mega Drive games such as ''Street Fighter II'', the six-button gamepad was released for a more arcade-like experience. This version of the gamepad featured {{X}}, {{Y}} and {{Z}} buttons in addition to the standard {{A}}, {{B}} and {{C}}, along with a new Mode button.  The European MegaDrive version has a reddish-orange start button to match the power and reset switches on their MegaDrive 2 console.  2-Piece D-Pad
 
|-
 
|[[Image:Pad_gen3.jpg|150px]]
 
|valign="top"|'''Sega Genesis 3 Gamepad "MK-1470"''': This was the controller which was included with the [[Genesis 3]] console.  As the Genesis 3 was an economy model, manufacturer [[Majesco]] sourced them from a third-party manufacturer.  This design became the most popular design and was simply rebranded with a different logo for each third-party company who decided to market it. It features six buttons, mode and start, and includes a switch to enable rapid-fire for all 6 buttons and slow motion via rapid pause.  The design is a blatant rip-off of the Japanese 6-Button pad, but the molding does not match exactly.  2-Piece D-Pad with arguable effectiveness.
 
|-
 
|[[Image:Pad_gen_megafire.jpg|150px]]
 
|valign="top"|'''Sega Megafire Gamepad, Genesis version "Model No. 1657"''': The Sega Megafire is an official version of the then-popular "turbo" controllers of the time, which offered autofire capabilities. The gamepad offers autofire for {{A}}, {{B}} and {{C}} buttons, and has cardinal direction arrows on the d-pad in red; it also used the improved ball-bearing D-Pad mechanism. The Genesis version has the Genesis logo printed on it.
 
|}
 
===Europe===
 
{|class="prettytable"
 
!Picture||Description
 
|-
 
|[[Image:Pad MD PAL I.jpg|150px]]
 
|valign="top"|'''Sega Mega Drive Gamepad, PAL Type I''': The Sega Mega Drive Gamepad for PAL regions is extremely similar to the Sega Genesis gamepad; however, it has "Mega Drive Control Pad" and the Sega logo printed in lieu of the Sega Genesis logo.
 
|-
 
|[[File:Pad MD PAL II.jpg|150px]]
 
|valign="top"|'''Sega Mega Drive Gamepad, PAL Type II''': The second model of Mega Drive gamepad. Mostly identical to the type I varient, however now features a red {{Start}} button instead of a white one. Model IIs were released with the Sega Mega Drive II, and would become the default controller for the years that followed.
 
|-
 
|[[Image:Pad MD Megafire.jpg|150px]]
 
|valign="top"|'''Sega Megafire Gamepad, MegaDrive version''': The Sega Megafire is an official version of the then-popular "turbo" controllers of the time, which offered autofire capabilities. The gamepad offers autofire for {{A}}, {{B}} and {{C}} buttons, and has cardinal direction arrows on the d-pad in red; it also used the improved ball-bearing D-Pad mechanism. The MegaDrive version has text printed in an arc at the top of the face like the regular 3-Button controller, and obviously is lacking the Genesis logo.
 
|}
 
  
===Brazil===
+
<gallery widths="200px">
{|class="prettytable"
+
File:Pad MD JP I.jpg|SJ-3500 (Japan; 1988)
!Picture||Description
+
File:MD JP Control Pad late model.jpg|SJ-3500 (Japan; 1991)
|-
+
File:Pad_gen_v1.jpg|MK-1650 (US; 1989)
|[[Image:Pad MD Tectoy.jpg|150px]]
+
File:Pad MD Gen.jpg|MK-1650 (US; 1991)
|valign="top"|'''Sega Mega Drive Gamepad, "MK-1470"''': A radically different design, this 6-button pad has a Turbo and slow-motion switch just like the Genesis 3 control pad. This model had a unique D-Pad implementation; a plastic spike or pillar was raised from the rear portion of the chassis and protruded through the circuit-board inside. The point of the spire is what the D-Pad rested on for its rocking motion. Of note is the model number on the rear of the pad, "MK-1470" which is the same as the Genesis 3 pad.  Perhaps Sega used this as a general designation for any 6-button controllers licensed from a third-party source.  The Sega logo is embossed on the rear of the controller, as well as the plug. This control pad was made by Tectoy, in Brazil.
+
File:Pad_gen_v3.jpg|MK-1650 (US; 1991)
|}
+
File:MDControlPad EU 3BV2.jpg|(Europe; 1990)
 +
File:Pad MD PAL I.jpg|(Europe; 1991)
 +
File:Pad MD PAL II.jpg|(Europe; 1993)
 +
File:MDControlPad SK 1.jpg|(South Korea; 1990)
 +
</gallery>
  
 
==Technical Information==
 
==Technical Information==
 
+
The 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:
===3-button gamepads===
 
The chip inside the gamepad 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:
 
  
 
{|class="prettytable"
 
{|class="prettytable"
Line 97: Line 82:
 
|}
 
|}
  
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:
+
All the controls are done with switches.  Up is a switch, Down is a switch, etc. 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
 
     +5V -----/\/\/------+--------- Output
Line 123: Line 108:
 
|Line 4||Pin 7 of the chip. Output 2Y.
 
|Line 4||Pin 7 of the chip. Output 2Y.
 
|-
 
|-
|Line 5||This line carries in +5V.  It is connected to the +5V bus line.
+
|Line 5||This line brings in +5V.  It is connected to the +5V bus line.
 
|-
 
|-
 
|Line 6 (TL)||Pin 9 of the chip. Output 3Y.
 
|Line 6 (TL)||Pin 9 of the chip. Output 3Y.
 
|-
 
|-
|Line 7 (TH)||Pin 1 of the chip. This carries in a select signal from the Genesis. This is a signal which varies rapidly and controls which input goes through the output
+
|Line 7 (TH)||Pin 1 of the chip. This carries in a select signal from the Genesis. This is a signal which varies rapidly and controls which input goes through the output.
 
|-
 
|-
 
|Line 8||Ground. This is connected to the Ground bus line.
 
|Line 8||Ground. This is connected to the Ground bus line.
Line 135: Line 120:
 
   
 
   
 
   
 
   
Now for the chips pin connections:
+
Now for the chip's pin connections:
 
   
 
   
 
{|class="prettytable"
 
{|class="prettytable"
Line 172: Line 157:
 
|}
 
|}
  
===6-button gamepads===
+
==Reading==
 +
Access to the controller ports is from bytes $A10003 (controller 1) and $A10005 (controller 2). TH must be set for output and the other pins for input, so bytes $A10009 and $A1000B must be set to $40 to read the respective controller.
  
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.
+
{| class="prettytable"
 
 
The full controller state is read in 8 cycles:
 
 
 
{|class="prettytable"
 
!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
+
! Bit !! 7 !! 6 !! 5 !! 4 !! 3 !! 2 !! 1 !! 0
 
|-
 
|-
|6||LO||Start||A||0||0||0||0
+
! Pin !! - !! TH !! TL !! TR !! R !! L !! D || U
 
|-
 
|-
|7||HI||C||B||Mode||X||Y||Z
+
! TH = 0
 +
| ? || 0 || S || A || 0 || 0 || D || U
 
|-
 
|-
|8||LO||Start||A||---||---||---||---
+
! TH = 1
 +
| ? || 1 || C || B || R || L || D || U
 
|-
 
|-
 
|}
 
|}
  
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.
+
Bit 7 latches the value written to it. It takes approximately the equivalent of two nop instructions for other types of controllers (such as the six-button controller) to respond to a TH change.
 
 
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 Genesis 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.)
+
==External links==
 +
* [https://web.archive.org/web/*/http://sega.jp/fb/segahard/md/pad.html Sega of Japan catalogue page (Japanese)]
  
==Physical Scans==
+
==Physical scans==
<gallery>
+
{{Scanbox
File:MDController SJ3500 JP Box Front.jpg|JP box (SJ-3500) (front)
+
| console=Mega Drive
File:MDController SJ3500 JP Box Back.jpg|JP box (SJ-3500) (back)
+
| region=JP (1988)
File:MDController SJ6000 JP Box Front.jpg|JP box (SJ-6000) (front)
+
| front=MDController SJ3500 JP Box Front.jpg
File:MDController MK-1470 US Box Front.jpg|US box (MK-1470) (front)
+
| back=MDController SJ3500 JP Box Back.jpg
File:MDController EU Box Front.jpg|EU box (front)
+
| spinemissing=yes
File:MDController MK1653 EU Box Front.jpg|EU box (MK-1653) (front)
+
| square=yes
</gallery>
+
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=JP (1991)
 +
| front=MDController SJ3500 1991 JP Box Front.jpg
 +
| back=MDController SJ3500 1991 JP Box Back.jpg
 +
| spinemissing=yes
 +
| square=yes
 +
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=US (1989)
 +
| front=MDControlPad US 3BV1 Box Front.jpg
 +
| back=MDControlPad US 3BV1 Box Back.jpg
 +
| spinemissing=yes
 +
| square=yes
 +
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=US (1992)
 +
| front=ControlPad MD US Box Front 1992.jpg
 +
| back=ControlPad MD US Box Back 1992.jpg
 +
| spinemissing=yes
 +
| square=yes
 +
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=US (1993)
 +
| front=ControlPad MD US Box Front 1993.jpg
 +
| back=
 +
| spinemissing=
 +
| square=yes
 +
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=EU (1990)
 +
| front=MDControlPad EU 3BV2 Box Front.jpg
 +
| back=
 +
| spinemissing=
 +
| square=yes
 +
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=EU (1993)
 +
| front=MDControlPadEU93 front.JPG
 +
| back=MDControlPadEU93 back.JPG
 +
| spinemissing=yes
 +
| square=yes
 +
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=CA (1989)
 +
| front=ControlPad MD CA Box Front Old.jpg
 +
| back=
 +
| spinemissing=
 +
| square=yes
 +
}}{{Scanbox
 +
| console=Mega Drive
 +
| region=CA (1993)
 +
| front=ControlPad MD CA Box Front New.jpg
 +
| back=ControlPad MD CA Box Back New.jpg
 +
| spinemissing=yes
 +
| square=yes
 +
}}
  
 
{{MegaDrive}}
 
{{MegaDrive}}
  
[[Category:Mega Drive Accessories]]
+
[[Category:Control pads]]
[[Category:Control Pads]]
 

Revision as of 23:25, 17 May 2018

Pad MD JP I.jpg
Control Pad
Made for: Sega Mega Drive
Manufacturer: Sega
Release Date RRP Code
Sega Mega Drive
JP
¥2,0002,000[1] SJ-3500
Sega Mega Drive
US
MK-1650
Sega Mega Drive
EU
Sega Mega Drive
CA
1650-22

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, replacing 1 and 2 with A and B respectively, while adding an extra two face buttons, C and  START  to bring the total number of buttons to four. Also featured is a circular D-Pad, designed to allow for movements in eight directions. Unlike Nintendo's systems, the buttons (or "triggers" as they were initially called) are arranged in alphabetical order from left to right, a practise which would continue not only with future Sega consoles, but would inspire the controllers of the Neo Geo, 3DO and Xbox lines.

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.

Variations

Control pads remained mostly the same across regions, but the colouring can determine the region and revision of the accessory. A minor addition added in the early 1990s is a little plastic lump on the B button, presumably to help users recognise where their right hand thumb was.

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 prevents wear which plagues the original design, which uses a plastic nub for the rocking motion and will eventually wear down with frequent use. Later versions employ a D-Pad with a two-piece fulcrum design as seen on the Six Button Control Pad and all Sega Saturn pads.


Technical Information

The 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:

Pin 1 Select
Pin 2 1A
Pin 3 1B
Pin 4 1Y
Pin 5 2A
Pin 6 2B
Pin 7 2Y
Pin 8 Gnd
Pin 9 3Y
Pin 10 3B
Pin 11 3A
Pin 12 4Y
Pin 13 4B
Pin 14 4A
Pin 15 G (? must be low)
Pin 16 Vcc (+5V)

All the controls are done with switches. Up is a switch, Down is a switch, etc. 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       |
                        |
               /        |
  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
Line 1 Up output.
Line 2 Down output. These are the only two direct connections.
Line 3 Pin 4 of the chip. Output 1Y.
Line 4 Pin 7 of the chip. Output 2Y.
Line 5 This line brings in +5V. It is connected to the +5V bus line.
Line 6 (TL) Pin 9 of the chip. Output 3Y.
Line 7 (TH) Pin 1 of the chip. This carries in a select signal from the Genesis. This is a signal which varies rapidly and controls which input goes through the output.
Line 8 Ground. This is connected to the Ground bus line.
Line 9 (TR) Pin 12 of the chip. Output 4Y.


Now for the chip's pin connections:

Pin 1 Line 7 (select)
Pin 2 Ground (1A)
Pin 3 Left (1B)
Pin 4 Line 3 (1Y)
Pin 5 Ground (2A)
Pin 6 Right (2B)
Pin 7 Line 4 (2Y)
Pin 8 Ground (GND)
Pin 9 Line 6 (3Y)
Pin 10 Button B (3B)
Pin 11 Button A (3A)
Pin 12 Line 9 (4Y)
Pin 13 Button C (4B)
Pin 14 Start (4A)
Pin 15 Ground (G)
Pin 16 +5V (Vcc)

Reading

Access to the controller ports is from bytes $A10003 (controller 1) and $A10005 (controller 2). TH must be set for output and the other pins for input, so bytes $A10009 and $A1000B must be set to $40 to read the respective controller.

Bit 7 6 5 4 3 2 1 0
Pin - TH TL TR R L D U
TH = 0 ? 0 S A 0 0 D U
TH = 1 ? 1 C B R L D U

Bit 7 latches the value written to it. It takes approximately the equivalent of two nop instructions for other types of controllers (such as the six-button controller) to respond to a TH change.

External links

Physical scans

Mega Drive, JP (1988)
MDController SJ3500 JP Box Back.jpgNospine-small.pngMDController SJ3500 JP Box Front.jpg
Cover
Mega Drive, JP (1991)
MDController SJ3500 1991 JP Box Back.jpgNospine-small.pngMDController SJ3500 1991 JP Box Front.jpg
Cover
Mega Drive, US (1989)
MDControlPad US 3BV1 Box Back.jpgNospine-small.pngMDControlPad US 3BV1 Box Front.jpg
Cover
Mega Drive, US (1992)
ControlPad MD US Box Back 1992.jpgNospine-small.pngControlPad MD US Box Front 1992.jpg
Cover
Mega Drive, US (1993)
ControlPad MD US Box Front 1993.jpg
Cover
Mega Drive, EU (1990)
MDControlPad EU 3BV2 Box Front.jpg
Cover
Mega Drive, EU (1993)
MDControlPadEU93 back.JPGNospine-small.pngMDControlPadEU93 front.JPG
Cover
Mega Drive, CA (1989)
ControlPad MD CA Box Front Old.jpg
Cover
Mega Drive, CA (1993)
ControlPad MD CA Box Back New.jpgNospine-small.pngControlPad MD CA Box Front New.jpg
Cover


Sega Mega Drive
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New Mega Drive | Tianli VCD/DVD Players | "Consoles on a chip" | Licensed clones (Magic 2 | Mega Game II | Power Pegasus | Super Bitman)
Unlicensed clones
Add-ons Game Box | Power Base Converter | Mega-CD | 32X (Mega-CD 32X) | Mega Modem | Demo System DS-16
Cases Sega Genesis Nomad Carrying Case | System Carry Case
Controllers Control Pad | Six Button Control Pad | 6 Button Arcade Pad | Arcade Power Stick 6B | Konami Justifier | MK-1470
Action Chair | Activator | Arcade Power Stick | Keyboard | MegaFire | Mouse | Mega Stick | Menacer | Remote Arcade System | Ten Key Pad | Third Party Controllers
Accessories 4 Way Play | Cleaning System | Control Pad Extension Cord | Genesis Speakers | Headset | HeartBeat Catalyst | Microphone | Region converter cartridges | Mega Terminal | Nomad PowerBack | RF Unit (Mega Drive 2) | SCART Cable (Mega Drive 2) | Stereo Audio Video Cable | Team Player | Video Monitor Cable | Third Party Accessories
Network services Sega Channel | Sega Game Toshokan | Mega Anser | Mega Net | TeleBradesco Residência | XB∀ND
Development tools ERX 308P | ERX 318P | Sprobe | SNASM68K | SNASM2 (Mega Drive) | SNASM2 (32X) | PSY-Q Development System (Mega Drive) | PSY-Q Development System (32X) | 32X CartDev | Sega Mars Development Aid System | Sega 32X Development Target
Unreleased Edge 16 | Floppy Disk Drive | Mega Play 1010 | Sega VR | Teleplay System | Video Jukebox