This is something that I built in year 2000 as a final project for an Industrial Electronics vocational course that I was taking at the time. This thing interfaces with a generic PC via IDE channel to allow for 2-way communication with an NES cart. I originally used it to program battery-backed NROM-based RAM carts to test experimental code on a real NES machine. Upon graduation, I won a governor general's award in that course. The copper clad board is an old ISA bus decoder card which was replaced with the IDE interface some time after initial production.
Here is also a 2C02 (the NES's PPU chip) reverse-engineering kit that interfaces with the NES devkit. I learned some of the most intimate details of the 2C02's operation with this setup.
Other sketches here represent a project I was working on in December 2006. This invention was intended to be a standalone NES devkit, in that it would use an actual NES as the host development system. The main schematic contained 2KB of RAM that would essentially contain the devkit's BIOS code. I gutted and reverse-engineered an IBM keyboard, in order to adapt it to this project. The devkit has provisions for 6502 interrupt vector swapping, so that on a push of a keyboard key, the game animation could halt and have the BIOS functions take over the system control. I abandonned the project after I realized that I forgot to battery-back the 2K RAM on the main schematic, because I had already spent so much time optimizing the circuit design for fabrication.