Update: project completed and posted here.
I’ve been working on a small device to let you ‘burn’ your own code to a chip and run it on a Super Nintendo. The main point of the device is to allow me to create customized versions of NBA JAM and play them on SNES hardware. My device replaces the stock ROM chip inside the SNES game cartridge. I just finished the design and sent the files off for the board to be manufactured.
It’s a two-layer board, black soldermask, white silkscreen. Hand routed (meaning I made all the connections by hand rather than letting the computer do it automatically…the auto-router is trash) with a ground pour on the bottom layer, and a 5V pour on the top layer.
The board has a 3D model for every part — I spent many an hour struggling with Solidworks and STEP files to get everything how I wanted it. My excuse? I’m not a mechanical engineer!
The brain of the board is an Atmel ATMEGA32u4 microcontroller, which is admittedly heavy overkill for this project. I wanted to play with the chip though, so I ordered a couple. You could probably even get away with an ATMEGA16u2 but the packages they come in are less hobbyist friendly.
What is sorta cool about this board is that pretty much every pin is broken out from the ATMEGA32u4, so the board could also be used as a generic breakout board with a little manual reworking.
There are solder pads to connect an Atmel ISP programmer, should one choose to program the device that way. I intend to experiment with the preloaded Atmel USB bootloader, which allows you to update program code over a USB connection without any special programming device.
It’s hard to tell the relative size of this board from the pictures, but it’s very small – about 1″ x 2.5″. (Which made all that hand-routing super tedious!)
To ensure all my footprints were correct, I had my design laser cut into some cardboard @ Pumping Station One. This worked out really well and actually turned out to be very helpful. The footprint I had made for the 16 MHz oscillator was technically correct, but fairly difficult to hand-solder. I widened up the pads a bit and that should make it easier for me to assemble.
I will have more info and pictures in the upcoming days – the boards should be here in a couple weeks. I ordered from the folks at iTead Studio.
I’ll take some pictures during the assembly and testing of the boards, and some final shots of everything working in perfect harmony all on the first go. (Yeah, right.)
Design files –schematics, Gerbers and a BOM — for the project will be released once the boards come back to me and test out OK.