Shared Projects by Wilykat

One player only version, smaller and cheaper. For two player version which costs more, see https://oshpark.com/shared_projects/vyZarCKm

BOM and additional information is at https://www.reddit.com/r/Famicom/comments/tzylv7/neo_geo_controller_to_nes_and_famicom_adapter/?

If you have a Computer Place numeric keypad for Commodore C64 and Vic 20 but do not have the necessary adapter to connect the keypad to the C64/20’s keyboard connector and motherboard, this is what you need.

For CP Numeric Keypad model number NKP

The board design is nearly a 1:1 copy of the original with the added silkscreen and solder mask plus cool Commodore logo.

BOM: 14 pin IC socket, 300 mils, this goes on the top. 20 pin female connector, 0.1" spacing (often called Dupont), this goes on the bottom. 20 pin male connector, 0.1" spacing and 90 degree angle. Be sure to remove pin #2 (at KEY location on PCB) before soldering. This goes on the top.

Allows the use of Sega Genesis or 2600 controller to work on 5200

I took the cloned UNO R3 design from Shamduino, replaced the FTDI chip with CH340 chip. FDTI costs about $4.50 each from legit source, and fake FTDI may be cheaper but once before a driver update bricked fake chips. CH340 is cheaper and there’s no driver bricking but you may need to manually install the driver on Windows and Macintosh. I also tweaked a few things. You have a choice of CH340G (cheaper, requires 3 additional components) or CH340C (doesn’t required additional components but slightly more expensive).

Soldering CH340, the dual op amp, and one MOSFET is probably the hardest part of this board.

I kept most of the parts the same using larger SMD for easier soldering. Printable copy of part location map and BOM can be seen below: “A” on map denotes anode of diodes, observe polarity! Also watch for notches or pin 1 marker on the 3 ICs. Orient the polarized capacitor with the angled end matching silkscreen. Crystal oscillators, ceramic capacitors, and resistors are non polarized and can be installed any way without issues.

text based BOM:

*CH340G requires external oscillator and 2 capacitors. If you have CH340C instead, the oscillator and 2 capacitors marked C15, C16, and Q1 above can be omitted.