Turn a Classic Controller into an SNES controller with Arduino Nano
All the classic controller I2C timing is measured with SNES Classic Mini (I2C speed is 200KHz).
Some non-official classic controller (like PS2 to classic controller) need 200KHz speed, official one can run with 300KHz.
But both can not work properly with 400KHz speed.
Schematic
IMPORTANT:
Remember to disconnect 5V from SNES when you plug Arduino Nano into USB port for safety.