Classic+ is a hardware emulator that replaces the Wii Classic Controller and Nunchuk.
Classic+ normally operates as a Classic Controller. Nunchuk mode can be enabled at any time by connecting the MD pin to GND. The device can be temporarily disabled by connecting the EN pin to GND. The SDA, SCL, and DET pins should be connected to a Wii Remote expansion port. Unofficial Wii Remotes may not be supported.
The Wii Remote IR camera can be emulated using the right joystick only in Nunchuk mode. This feature is only supported on non-TR Wii Remotes. The real IR camera must be removed from the Wii Remote before using IR camera emulation. Sensitivity adjustment is available in the homebrew app.
Soldering the accelerometer IC is optional. Without it, Nunchuk mode will report neutral values.
Classic+ works with Wii Remotes and SNES Classic. NES Classic support is untested.
PCBs can be ordered here: https://oshpark.com/shared_projects/poSQyyw2
Place update.hex from the Firmware folder on the root of an SD card or USB storage device. Run the Wii homebrew app with a Classic+ board connected to a Wii Remote and select "Update Classic+". Note that the update process can take up to 10 minutes.
Safe mode can be enabled by holding the X and Y buttons when the Classic+ powers on. Safe mode only supports updating through the homebrew app. Buttons, joysticks, and calibration will not work.
Flash the pre-compiled firmware.hex using MPLAB IPE with a PICkit 3.
Make a project in MPLAB X IDE for PIC16F18876 with the XC8 compiler. The Bootloader and Main Program must be compiled as separate projects and flashed onto the same device using the code offset and Preserve Program Memory features or by manually combining the compiled .hex files.