DB9 joystick port interfers with C64

simonsunnyboy / SNES2DB9

SNES2DB9 is a software package to allow implementation of a converter to connect a SNES style gamepad with shift register to a system using the Atari DB9 joystick standard (Atari 2600, C64, Amiga, Atari ST, etc.)

MIT License

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DB9 joystick port interfers with C64 #1

Closed simonsunnyboy closed 3 years ago

simonsunnyboy commented 3 years ago

When plugged into a Commodore 64, the SNES2DB9 implementation with ATtiny84 works but the keyboard is not responding anymore.

simonsunnyboy commented 3 years ago

Solution: The pins are either HIGH-Z for idle or pulled to GND. Pull-ups should not be used.

Software changes:

SNES2DB9 core should signal "set to pin to HIGH_Z" state if necessary.
ATtiny84 implementation needs fixes to service pins accordingly.