Originally Posted by wXR
Perchance, is C64 reloaded a board that can work with unmodified Sega Genesis pads, without blowing the CIA (even when mashing keys at the same time)?
Nope - Sega gamepads do not comply with the standard that Commodore and Atari have established back in the days. You should never connect an unmodded Sega gamepad to other computers but a Sega gaming system.
It's the same as with serial ports on a PC: They have the same physical connector, but it's a different protocol and different voltages. There's the danger of breaking the device, the computer's port, or even both.