The Atari 5200 SuperSystem (1982) includes a rear expansion port behind a removable door, intended as provisional circuitry for future peripheral development. The port exposes a subset of the console’s internal bus — including address and data lines, serial I/O, clock, audio, and control signals — but no compatible expansion device was ever released commercially by Atari. The connector carries both 6502 bus signals and POKEY-derived serial and audio lines, reflecting the console’s internal architecture based on the same custom chips (6502 CPU, ANTIC, GTIA, POKEY) used in the Atari 8-bit home computers.
| Pin | Name |
|---|---|
| 1 | +5 VDC |
| 2 | Audio Out (2 port) |
| 3 | Ground |
| 4 | R/W Early |
| 5 | Enable E0-EF |
| 6 | D6 |
| 7 | D4 |
| 8 | D2 |
| 9 | D0 |
| 10 | IRQ |
| 11 | Ground |
| 12 | Serial Data In |
| 13 | Serial In Clock |
| 14 | Serial Out Clock |
| 15 | Serial Data Out |
| 16 | Audio In |
| 17 | A14 |
| 18 | System Clock 01 |
| 19 | A11 |
| 20 | A7 |
| 21 | A6 |
| 22 | A5 |
| 23 | A4 |
| 24 | A3 |
| 25 | A2 |
| 26 | A1 |
| 27 | A0 |
| 28 | Ground |
| 29 | D1 |
| 30 | D3 |
| 31 | D5 |
| 32 | D7 |
| 33 | Not connected |
| 34 | Ground |
| 35 | Not connected |
| 36 | +5 VDC |
Notes
The expansion port sits behind a removable door at the rear of the console. Atari described it as provisional circuitry for future development; no pinout specification was published by Atari and no commercial expansion device reached the market. Pin 2 (Audio Out) is specific to the 2-port model variant.
Signals
- +5 VDC — regulated 5 V logic supply (pins 1 and 36)
- Audio Out — analogue audio output from POKEY (2-port model)
- Ground — common ground reference (pins 3, 11, 28, 34)
- R/W Early — read/write direction signal from the 6502 CPU (early phase)
- Enable E0-EF — chip-enable for address range $E000–$EFFF
- D0–D7 — 8-bit bidirectional data bus (D0 on pin 9, D1–D7 distributed across pins 29, 8, 30, 7, 31, 6, 32)
- IRQ — maskable interrupt request line
- Serial Data In — POKEY serial data input
- Serial In Clock — POKEY serial input clock
- Serial Out Clock — POKEY serial output clock
- Serial Data Out — POKEY serial data output
- Audio In — analogue audio input for mixing
- A0–A14 — address bus lines (15 lines; A0 on pin 27 through A14 on pin 17, with A8–A13 not listed — purpose of absent address lines unknown)
- System Clock 01 — phase-1 system clock derived from the console oscillator
- Not connected — pins 33 and 35 are unpopulated