SG-1000:Connector Pinouts
Cartridge Port
Note: Pins A1 through A22 are towards the back and numbered from left to right, B1 through B22 are towards the front and also numbered from left to right. On the SC-3000, A1 through A22 are towards the bottom and B1 through B22 are towards the top.
| Pin # | Description | Pin # | Description |
|---|---|---|---|
| A1 | A0 | B1 | 5V |
| A2 | A1 | B2 | 5V |
| A3 | A2 | B3 | !OSRAM (SG-1000 and SC-3000) / !CSRAM (SG-1000 II) |
| A4 | A3 | B4 | !EXM1 (SG-1000 and SG-1000 II) / !CEROM (SC-3000) |
| A5 | A4 | B5 | !RD (SG-1000 and SG-1000 II) / !MEMR (SC-3000) |
| A6 | A5 | B6 | !WR (SG-1000 and SG-1000 II) / !MEMW (SC-3000) |
| A7 | A6 | B7 | Unused (SG-1000 and SG-1000 II) / I/O R (SC-3000) |
| A8 | A7 | B8 | Unused (SG-1000 and SG-1000 II) / I/O W (SC-3000) |
| A9 | A8 | B9 | !RFSH (SG-1000) / Unused (SC-3000 and SG-1000 II) |
| A10 | A9 | B10 | !MREQ |
| A11 | A10 | B11 | CONT |
| A12 | A11 | B12 | Unused (SG-1000 and SG-1000 II) / !RAS1 (SC-3000) |
| A13 | A12 | B13 | Unused (SG-1000 and SG-1000 II) / !CAS1 (SC-3000) |
| A14 | A13 | B14 | Unused (SG-1000 and SG-1000 II) / RAM A7 (SC-3000) |
| A15 | D0 | B15 | Unused (SG-1000 and SG-1000 II) / !RAS2 (SC-3000) |
| A16 | D1 | B16 | Unused (SG-1000 and SG-1000 II) / !CAS2 (SC-3000) |
| A17 | D2 | B17 | Unused (SG-1000 and SG-1000 II) / !MUX (SC-3000) |
| A18 | D3 | B18 | A14 |
| A19 | D4 | B19 | !EXM2 (SG-1000 and SG-1000 II) / A15 (SC-3000) |
| A20 | D5 | B20 | !M1 (SG-1000) / Unused (SC-3000 and SG-1000 II) |
| A21 | D6 | B21 | Ground |
| A22 | D7 | B22 | 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. This pinout is mostly identical to the later Sega Master System and Mark III.
| Pin # | Description |
|---|---|
| 1 | Up |
| 2 | Down |
| 3 | Left |
| 4 | Right |
| 5 | Unused |
| 6 | Button 1 |
| 7 | Ground (console side only on SG-1000 and SG-1000 II) / Unused (SC-3000 only) |
| 8 | Ground |
| 9 | Button 2 |
Expansion Port
This expansion port is only found on the SG-1000, SG-1000 II and Othello Multivision consoles.
Note: Pins are numbered from left to right with the edge of the connector facing forward.
| Pin # | Description |
|---|---|
| 1 | Ground |
| 2 | Ground |
| 3 | Ground |
| 4 | Ground |
| 5 | A2 |
| 6 | Unused |
| 7 | IOREQ |
| 8 | CONT |
| 9 | Write |
| 10 | Read |
| 11 | KBSEL |
| 12 | D7 |
| 13 | D6 |
| 14 | D5 |
| 15 | D4 |
| 16 | D3 |
| 17 | D2 |
| 18 | D1 |
| 19 | D0 |
| 20 | A1 |
| 21 | A0 |
| 22 | Unused |
| 23 | 5V |
| 24 | 5V |
SC-3000 Monitor Out
Note: Female connector is pictured. The same pinout is also used on the Master System and Genesis/Mega Drive.
| Pin # | Description |
|---|---|
| 1 | Composite Video Out |
| 2 | Ground |
| 3 | Audio Out |
| 4 | Unused |
| 5 | Unused |
Yeno SC-3000 Monitor Out
Note: Female connector is pictured.
| Pin # | Description |
|---|---|
| 1 | Composite Sync |
| 2 | Ground |
| 3 | Audio Out |
| 4 | Vertical Sync |
| 5 | Horizontal Sync |
| 6 | Green |
| 7 | Blue |
| 8 | Red |