For the Option B schema the following components have been added:

  • One Hex Inverter 7406
  • 2 Pull Up resistors 1K
  • 1 Ceramic capacitor 100nF (not used)

I decided to do not pickup the power from Raspberry PI. I added an external power supply attached to the breadboard: it supplies both 5V and 3.3 V.

There are no switch buttons. Only the status LED and the piezo buzzer.

The Option B solution is recommended if you want to attach additional Commodore devices to the IEC bus.

Always thanks to Steve White – Pi1541 project link