UP9600: How to Bit-Bang 9600 Baud RS-232 on the C64

The user port of the Commodore 64 exposes a TTL-level RS-232 serial port that supports up to 1200 baud1. In 1997, Daniel Dallmann came up with a very sophisticated trick that allowed sending and receiving at 9600 baud2, using slightly different wiring and a dedicated driver. This “UP9600” wiring has become the de-facto standard for all modern accessories, like C64 WiFi modems. Let’s see how UP9600 works. read more

Converting the “Competition Pro Extra USB” to C64/Amiga/Atari DB9

  • Updated 2022-03-09: Added “SL-6603-TWT” pinout. Thanks a lot to Risto K for the infos and the photos!
  • Updated 2022-01-26: Added “V2” pinout.
  • Updated 2022-01-22: Added “SL-6603-SPORTS-DE” pinout.
  • Updated 2022-01-14: Added “SL-6603-SBK” and “KOKA” pinouts.
  • Updated 2022-01-06: Added new “V3” and “V04T” pinouts and instructions on how to use a joystick extension cable.

Speedlink makes several versions of the Competition Pro joystick that have all the physical properties and the excellent switches of the original Competition Pro, but come with a USB interface: read more