The Commodore C65 (internally designated the C64DX) was a prototype next-generation home computer developed by Commodore Business Machines; it was never commercially released and all known units are pre-production machines. According to the C64DX System Specification (Revision 0.2, January 1991), video output is handled by the CSG 4567 chip and provided via three connectors: an 8-pin DIN composite video and audio port, a DB-9 analogue RGB video port, and an RF modulator. The video chip supports analogue RGBA with sync on all colours or a separate digital sync signal, as well as composite NTSC/PAL video with separate chroma and luma, and digital foreground/background (genlock) control. Because the specification is a pre-production engineering document, the chip descriptions note that changes were expected before any production release.
9 PIN D-SUB MALE at the Computer.
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | GND | - | Ground |
| 2 | ? | ? | ? |
| 3 | R | OUT | Red |
| 4 | G | OUT | Green |
| 5 | B | OUT | Blue |
| 6 | ? | ? | ? |
| 7 | CSYNC | OUT | Composite Sync |
| 8 | HSYNC | OUT | Horizontal Sync |
| 9 | VSYNC | OUT | Vertical Sync |
Signals
- GND — Signal ground reference.
- R — Analogue Red video output.
- G — Analogue Green video output.
- B — Analogue Blue video output.
- CSYNC — Composite sync output (combined horizontal and vertical sync).
- HSYNC — Horizontal sync output.
- VSYNC — Vertical sync output.
- Pin 2 / Pin 6 — Purpose not publicly documented; the C64DX System Specification Revision 0.2 does not provide a per-pin assignment for these positions on the DB-9 RGB port.
Notes
- Direction is Computer relative to Monitor.
- The C65 DB-9 analogue RGB port is described in a pre-production prototype specification (Revision 0.2, January 1991); pin assignments for pins 2 and 6 are not documented in the known public text of that specification.
- The C65 was never commercially released; all known hardware units are prototypes, so connector behaviour may vary between individual machines.
- The CSG 4567 video chip supports both analogue RGB with sync-on-colour and composite NTSC/PAL with separate chroma and luma; the DB-9 port carries the analogue RGB output path.