[Frode] felt that using the keyboard for gaming on his old IBM XT computer was simply too noisy. He came up with a much quieter way to game by building an XT adapter for an original NES controller. If you haven’t explored the communication protocol used by the NES peripherals this is a great way to learn. Inside you’ll find a CMOS shift register that captures button states when it receives a latch signal. With that in mind [Frode] came up with a circuit to gather the bits from the controller, and generate input commands using the XT keyboard protocol without using a microcontroller. All of this is explained in the demo after the break.
Most of the NES controller hacks we see permanently alter the hardware. It’s nice to see one used without cracking it open.