Open hardware and software project for connecting a Commodore 64 User Port to a conventional RS-232 interface.
- Manufacturable KiCad PCB.
- C64 User Port as the native host interface.
- Standard RS-232 electrical interface, suitable for a DB9 connector.
- C64-side serial driver/API so applications do not need to manipulate CIA registers directly.
- Terminal and interoperability tooling.
- Future SLIP/IP networking over the serial link.
- Optional future PPP support after SLIP is established.
M0 — Architecture baseline: complete
The project now has a defined hardware/software boundary and implementation roadmap. Hardware implementation, driver implementation, and networking are intentionally separated from final qualification.
See ROADMAP.md.
C64 application
|
v
C64RS232 API / driver
|
v
CIA-based serial I/O
|
v
C64 User Port
|
v
RS-232 transceiver
|
v
DB9 RS-232
|
v
Host serial adapter / gateway
|
v
SLIP / IP (future)
The hardware target is a simple, robust 2-layer board using a dedicated RS-232 level-transceiver and charge-pump capacitors. Through-hole-friendly parts will be preferred where practical for easy assembly and repair.
The software stack will provide:
- low-level C64 serial I/O;
- configurable baud rates;
- buffering and status/error handling;
- terminal interoperability;
- SLIP framing and IP transport as a later milestone.
Qualification will cover schematic/PCB ERC/DRC, electrical loopback, real C64 serial interoperability, sustained transfers, and eventual SLIP/IP operation on physical hardware.
For fabrication files, release-package conventions, manufacturer choices, and funding/affiliate disclosure, see MANUFACTURING.md. Released hardware remains vendor-neutral and may be manufactured by any suitable PCB manufacturer. For project-specific PCB ordering options, see ORDERING.md.
Hardware design materials — including schematics, PCB layouts, manufacturing files, and HDL/RTL that describes hardware — are licensed under the CERN Open Hardware Licence Version 2 - Permissive (CERN-OHL-P-2.0). See LICENSE-HARDWARE.
Software — including firmware, drivers, host tools, emulators, assemblers, compilers, utilities, and other executable code unless explicitly stated otherwise — is licensed under the MIT License. See LICENSE-SOFTWARE.
Files that incorporate third-party material remain subject to their respective licences and notices.