Genesis:Connector Pinouts

AV Out (Model 1)

Note: Connector is the female end at the console.

Pin #	Description
1	Composite Video Out / Unused (French Mega Drive)
2	Ground
3	Audio Out
4	Green
5	5V
6	Composite Sync
7	Red
8	Blue

AV Out (Model 2 and 3)

This connector is also used in the Genesis Nomad, Mega Jet, 32X, CDX, and most X'Eye consoles. Ground is at the cable shroud.

Note: Connector is the female end at the console.

Pin #	Description
1	Blue
2	5V
3	Green
4	Composite Video
5	Composite Sync
6	Mono Audio
7	Red
8	Left Audio / Mono Audio (Genesis 3)
9	Right Audio / Unused (Genesis 3)

Cartridge Port

Note: The "A" row is towards the back and numbered from left to right. The "B" row pins are towards the front and also numbered from left to right. This table is oriented so the front of the port is facing left. All lines starting with a "V" are connected to the 68000 CPU.

Pin #	Description	Pin #	Description
B1	SL1 (External Left Audio) / Unused on Genesis 3	A1	Ground
B2	/MRES	A2	5V
B3	SR1 (External Right Audio) / Unused on Genesis 3	A3	VA8
B4	VA9	A4	VA11
B5	VA10	A5	VA7
B6	VA18	A6	VA12
B7	VA19	A7	VA6
B8	VA20	A8	VA13
B9	VA21	A9	VA5
B10	VA22	A10	VA14
B11	VA23	A11	VA4
B12	YS (Blanking) / Unused on Genesis 3	A12	VA15
B13	VSYNC (Vertical Sync) / Unused on Genesis 3	A13	VA3
B14	HSYNC (Horizontal Sync) / Unused on Genesis 3	A14	VA16
B15	EDCLK / Unused on Genesis 3	A15	VA2
B16	/CAS0	A16	VA17
B17	/CE_0 (Cartridge Enable)	A17	VA1
B18	/AS (Address Strobe)	A18	Ground
B19	VCLK / Unused on Genesis 3	A19	VD7
B20	/DTACK (Data Transfer Acknowledge)	A20	VD0
B21	/CAS2 / Unused on Genesis 3	A21	VD8
B22	VD15	A22	VD6
B23	VD14	A23	VD1
B24	VD13	A24	VD9
B25	VD12	A25	VD5
B26	/ASEL	A26	VD2
B27	/VRES (68000 Reset)	A27	VD10
B28	/LWR	A28	VD4
B29	/UWR	A29	VD3
B30	/M3 (Master System enable, must be held low to activate) / Unused on Genesis 3 and Nomad	A30	VD11
B31	/TIME	A31	5V
B32	/CART / Unused on Genesis 3	A32	Ground

Controller Port

Note: Female is connector at the console. Male is connector at the controller. Diagram pictured is of the connector at the controller end.

Pin #	Description
1	Up/Button Z
2	Down/Button Y
3	Left/Ground/Button X
4	Right/Ground/Mode
5	5V
6	Button B/A
7	Multiplexer Select
8	Ground
9	Button C/Start

Expansion Port

This connector is only found on model 1 and model 2 consoles.

Note: The "A" row is on the bottom and is numbered from left to right. The "B" row pins are on the top and are also numbered from left to right. This table is oriented so the front of the port is facing left. All lines starting with a "V" are connected to the 68000 CPU.

Pin #	Description	Pin #	Description
B1	Ground	A1	Ground
B2	/DISK	A2	VA19
B3	VA1	A3	/CAS0
B4	VA2	A4	VD0
B5	VA3	A5	VD1
B6	VA4	A6	VD2
B7	VA5	A7	VD3
B8	VA6	A8	VD4
B9	VA7	A9	VD5
B10	VA8	A10	VD6
B11	VA9	A11	VD7
B12	Ground	A12	Ground
B13	VA10	A13	VD8
B14	VA11	A14	VD9
B15	VA12	A15	VD10
B16	VA13	A16	VD11
B17	VA14	A17	VD12
B18	VA15	A18	VD13
B19	VA16	A19	VD14
B20	VA17	A20	VD15
B21	/LWR	A21	/ROM
B22	/UWR	A22	/ASEL
B23	/CAS2	A23	/RAS2
B24	/FDWR	A24	/FDC
B25	VA18	A25	/FRES
B26	5V	A26	5V
B27	SL3 (Expansion Audio Left, not used on Sega CD)	A27	SR3 (Expansion Audio Right, not used on Sega CD)
B28	5V In	A28	5V In
B29	SL2 (Expansion Audio Left)	A29	SR2 (Expansion Audio Right)
B30	Ground	A30	Ground

EXT Port

This connector is only found on older model 1 consoles, all model 1 Japanese Mega Drive consoles, the TeraDrive and Wondermega. It is located at the rear of these consoles, and is essentially identical to the controller ports, though is typically used to send serial data to the VDP instead of being used as an extra controller port. The most notable accessory to use this connector is the Mega Modem, which was only released in Japan.

Note: Diagram pictured is of the connector at the console end.

Pin #	Description
1	Up
2	Down
3	Left/Ground
4	Right/Ground
5	5V
6	Button B/A
7	Multiplexer Select
8	Ground
9	Button C/Start