FPGAs (Field-Programmable Gate Arrays) have been used for commercial research for decades now, but have just recently started to gain popularity among hobbyists. An FPGA essentially allows you to programmatically create actual hardware circuits, which means they can be used to reproduce ICs (Integrated Circuits) like processors. YouTuber Jon Thomasson has taken advantage of that capability to build a handheld console that emulates an NES with an FPGA.
Technically, “emulation” isn’t the correct word here. Emulation means a system’s capability is simulated in software. With an FPGA, the actual hardware of the system is being reproduced internally. That might seem like a small distinction to make, but it’s the reason that FPGAs have so much potential. In this case, that FPGA is a Spartan 6 that, with the help of a few other components, completely replicates the NES’s hardware. That includes the processor, sound chip, and everything else inside the console.
Thomasson mounted the Spartan 6 FPGA board onto a large perf board. Additional components include a TFT LCD from Adafruit, an SD card reader module for loading ROMs, a small amplifier for the speaker, and the buttons and batteries. The NES core for the FPGA was developed by Brian Bennett, and Thomasson modified that to work with this project. Because the NES’s hardware is actually being reproduced by the FPGA, games run exactly as they would on the original console — something that is difficult to achieve with traditional emulation.