The Atari Falcon030 DSP port is a 26-pin, three-row female connector (Cannon/ITT type) mounted on the rear of the computer. It exposes the Motorola DSP56001 digital signal processor’s Synchronous Serial Interface (SSI) and Sound DMA (SDMA) play and record channels, three general-purpose I/O lines, a DSP interrupt output, an external clock/GENLOCK input, and a +12V supply rail for peripheral power. The connector was intended to allow third-party DSP accelerators, audio interfaces, and studio peripherals to interface directly with the Falcon030’s on-board DSP. The pinout is documented in Atari Corporation’s own Technical Documentation dated 1 October 1992.
Cannon 26pin 3rows Female Connector on computer side.
| PIN | Description |
|---|---|
| 1 | General Purpose 0 |
| 2 | General Purpose 2 |
| 3 | General Purpose 1 |
| 4 | SDMA Play Data |
| 5 | SDMA Play Clock |
| 6 | SDMA Play Sync |
| 7 | Not Connect |
| 8 | Ground |
| 9 | +12V |
| 10 | Ground |
| 11 | Sync Serial I/F Ctrl 0 |
| 12 | Sync Serial I/F Ctrl 1 |
| 13 | Sync Serial I/F Ctrl 2 |
| 14 | Ground |
| 15 | Sync Serial Data In |
| 16 | Ground |
| 17 | +12V |
| 18 | Ground |
| 19 | SDMA Record Data |
| 20 | SDMA Record Clock |
| 21 | SDMA Record Sync |
| 22 | DSP Interrupt |
| 23 | Sync Serial I/F Data Out |
| 24 | Sync Serial I/F Clock |
| 25 | Ground |
| 26 | External Clock Input |
Signals
- GP0, GP1, GP2 — General-purpose I/O lines driven by the DSP56001; direction is software-configurable. GP0 is on pin 1, GP2 on pin 2, GP1 on pin 3.
- SDMA Play Data / Clock / Sync — Sound DMA playback channel (pins 4–6): serial audio data, bit clock, and frame sync for the outbound audio stream to an external codec or DAC.
- SDMA Record Data / Clock / Sync — Sound DMA record channel (pins 19–21): serial audio data, bit clock, and frame sync for the inbound audio stream from an external ADC or microphone pre-amp.
- Sync Serial I/F Ctrl 0–2 — SSI control lines 0, 1, and 2 (pins 11–13); configure operating mode, word length, and protocol for the DSP56001’s serial port.
- Sync Serial Data In — SSI receive data line (pin 15); carries serial data from an external device into the DSP56001.
- Sync Serial I/F Data Out — SSI transmit data line (pin 23); carries serial data from the DSP56001 to an external device.
- Sync Serial I/F Clock — SSI serial clock (pin 24); can be driven by the DSP56001 or by an external source depending on configuration.
- DSP Interrupt — Active output from the DSP56001 to signal the host CPU or an external peripheral (pin 22).
- External Clock Input — Accepts an external reference clock or GENLOCK signal (pin 26), allowing synchronisation with video or studio word-clock sources.
- +12V — Peripheral supply voltage on pins 9 and 17; intended to power external DSP expansion hardware, not for logic-level signalling.
- Ground — Multiple ground-return pins (8, 10, 14, 16, 18, 25).
- Not Connect — Pin 7 is explicitly listed as no-connect in the Atari Technical Documentation.
Notes
- The physical connector is a three-row, 26-way female socket on the computer (sometimes described as a Cannon/ITT D-sub variant); the mating peripheral plug is male.
- The +12V supply on pins 9 and 17 is for peripheral power only. DSP56001 logic signals operate at TTL-compatible levels; exact voltage margins are defined in the Motorola DSP56001 datasheet rather than in the Atari documentation.
- Signal voltages for the SSI and SDMA lines are not stated in the Atari Technical Documentation; they are governed by the DSP56001 specification (TTL/CMOS compatible, typically 3.3 V or 5 V depending on the chip variant and supply).
- The connector carries no standard audio interface protocol of its own; the SDMA and SSI signals implement whichever serial audio format the DSP56001 firmware selects (e.g. I²S, AC97, or custom framing).
- The External Clock Input (pin 26) may be used for GENLOCK to synchronise audio sample rates with an external video reference.