Tutorial – how to use GameCube controller on pc. Close the Dolphin emulator (if open). Plug the GameCube adapter into the USB ports of your computer. If you want to enable vibration and wireless controls, you must insert the two USB connectors included in the adapter.
If you have the official Nintendo Wii U adapter or the 4 port Mayflash adapter, then you can utilize Dolphin's native support for these adapters (Direct Connect). The Direct Connect feature has 0 input lag and is 100% accurate to a console. Always use this if you can. While using Direct Connect, Dolphin configure the controller to match console automatically. This being said, you should not use the GC Pad Settings and changing the settings there will not affect your controller while Direct Connect is on.
*Uninstall the vJoy driver if you have it installed. Only applies if you have installed vJoy in the past.
*If using the Mayflash adapter, set it to Wii U mode. Do not try to use PC Mode.
1. Download and open Zadig.
2. Open the options menu and click 'List All Devices'.
3. Select WUP-028 in the pulldown menu, and ensure the USB ID is 057E 0337. If you do not see this then try plugging the adapter (specifically the black USB cord) into a different USB port.
4.Select WinUSB on the right column then click Replace Driver and select Yes to modify the system driver.
5. Open Dolphin > Controllers. For Port 1, in the dropdown menu, select GameCube Adapter For Wii U and to verify that it works, click configure and make sure Direct Connect is selected and the adapter is detected:
(Quick Note: If you want rumble on and are using the Mayflash 4 port adapter, then you have to plug in BOTH USBs. The Official WiiU only needs one to activate rumble)
7. If you're adapter is NOT being detected, make sure you close all other instances of dolphin and restart 5.0-321.
**For other OS's, follow these respective guides ( Mac / Linux ).