While older gaming hardware may not be as advanced as modern technology, it has its unique advantages. Retro gaming systems, like the Nintendo Entertainment System (NES), offer a nostalgic appeal and a chance to gain a deeper understanding of their inner workings. The NES, which is nearly four decades old, is relatively simple compared to today’s standards. This simplicity makes it an ideal platform for modifications, such as creating a controller that enables automation.
The original NES controller used a basic shift register to send button presses to the system. The system would send a latch signal to the controller, which would then read the button states using the shift register and send them one by one to the system at a rate of approximately 1000 times per second. It is also possible to send these signals without a physical controller. The automated controller in this project utilizes a CD4021 shift register, similar to the original controller, but instead of reading button states, it receives inputs from a separate computer through a latching circuit. The separate computer used in this project is a custom design that originated from adapting cassette storage for a 6502-based computer, but any computer system can be used.
With this automated system, it becomes possible to automate gameplay to some extent. However, since the system cannot receive feedback about the game’s current state, precise timing and tuning are necessary to achieve optimal gameplay. This project is not an isolated endeavor either. Similar methods are employed to create tool-assisted speedruns, where gameplay is optimized using external tools. Although these speedruns are often performed on emulators rather than real hardware, they can still uncover interesting game exploits.