A spin on my GamecubePC, this project's goal was to fit a computer capable of emulating N64 games inside of the respective console's case. The current iteration is based around an Asus PN51-S1 Mini PC with 8GB of Crucial DDR4 3200MHz SO-DIMM RAM, a 256GB M.2 NVMe SSD, and a wireless module for WiFi/Bluetooth. It's powered by a Ryzen 5500U processor with Radeon graphics and is capable of running Nintendo 64 games at higher than native resolutions and full FPS.
A few 3D printed brackets provide the mounting points for a pair of custom PCBs, which are used to restore the original console's functionality. The controller port board houses the controller ports, power LED, and power switch, along with utilizing custom circuitry that allows the power switch to properly interface with the motherboard. The controller adapter board contains two 2-port USB adapters for N64 controllers connected to a 2-port USB hub, which plugs into a single-port header on the motherboard.
This last update shows off the finalized PC mounting and PCBA design solutions for the Asus PN51 variant of this N64 console computer mod.
The main controller board was broken out into two halves. The controller port board and the controller adapter board. The controller port board consists of the power switch circuitry, power LED, and original controller ports which are then re-routed to the controller adapter board.
The controller adapter board contains two 2-port USB adapters for N64 controllers routed to a 2-port USB hub with ESD suppression circuitry.
The mounting brackets were also improved upon by using a single 3D printed mount for the mini PC and A/V port cover, and then another mount for the controller adapter board, rather than several different pieces.
Since the Asus PN51 does not have provisions for a reset switch, a block-off spacer was designed to keep the N64 Reset button propped up in its un-actuated position.
Lastly, an adapter was made for the controller adapter board USB cable because in some cases, the adapter board was having intermittent connection issues with the motherboard's onboard header. This problem did not persist when using the front or rear USB Type-A ports on a different computer, so this adapter should solve that issue.
A custom PCB was designed to feature two 2-port N64-to-USB adapters routed to the original controller ports. Also included are the original reset and power switches, center power LED, and a custom circuit designed to send the proper shutdown signal to the Intel NUC. The board then bundles its I/O into a Molex Nano-Fit 16-pin header to interface with the motherboard. Status LEDs for the board power, motherboard power, power switch state, and reset switch state are also included. The control board's power switch logic circuitry is powered by a +5V auxiliary power header on the NUC, while the controller adapters still receive power through the 2-port USB 2.0 header.
The power switch requires some logic conversion to be able to properly power on and shut down the PC. A simple slide switch would not suffice, as the motherboard expects a pulse and not a constant signal. Twin 555 timers configured as one-shot pulse generators provide a single pulse for each "throw" of the slide switch. The output of each timer is then fed through an OR-gate, and then buffered to keep the circuit opto-isolated from the motherboard.
One minor flaw in this design is that it's possible for the power switch's position to become out-of-sync if operated too quickly, but this is easily rectified the next time the PC shuts down as you can unplug the device and move the switch back to the correct position.
Brackets were designed to adapt the stock N64 board mounts to the Intel NUC motherboard. In addition, an M.2-to-SATA adapter board can be mounted, as a full size 2.5" SSD was too large to comfortably fit in the case. A rear cover is also inserted behind the storage adapter to cover where the original AV port used to be accessed from.
A custom rear I/O shield matches the profile of where the stock AC adapter would normally plug into. Additional holes were added to mount the wireless antennas, and a vent allows the blower-style fan under the motherboard to exhaust out the rear of the case.