Picture of a GameBoy

Jeff Frohwein's GameBoy Tech Page
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Hardware

Original GB/Cart Diagrams

GameBoy Schematic

This is the older, full-size GameBoy main board.

GameBoy LCD Board Schematic

This is the schematic for the separate LCD board in the older, full-size GameBoy.

GameBoy Power & Cartridge Schematic

This is a schematic of the switching power supply onboard the older, full-size GameBoy as well as the two external power supplies available from Nintendo. An example EPROM cartridge is also here.

Super GameBoy Schematic

When I saw Super GameBoy's on sale at the local store, I though, "Do I need this?" The longer I though about this the more my curiosity of what might possibly be inside seemed to take over my whole thinking process. I reached the point of 'no return'. I had to buy it relieve my curiosity. What I discovered inside is basically that it seems that the Super GameBoy is a regular GameBoy minus some parts (i.e., LCD, keys, power supply). An extra chip is added to interface the GameBoy to the SNES to control key inputs and to capture video to display.

GameBoy Cartridge Information

Cartridge information on ROM-only & ROM/RAM cartridges. Provided courtesy of Pascal Felber.

ROM+RAM+MBC1 Cart Schematic

Now all but one pin is defined on the MBC1. Here is the 8 pin 134a chip found in MBC5 carts that contain RAM. It appears to be the same as the 26a chip found in MBC1 carts with RAM.

MBC1 Circuit Equivalent

For connecting an eprom larger than 256KBits to GameBoy you need a Nintendo MBC chip or you can use this circuit.

Game Link Related

Four-Player Adapter / Game Link Cable / Cable Adapter Schematic

Allows 4 GBs to connect together for multi-player games that support it.

GameBoy - to - Parallel Port Cable, Rev G

Diode added. Diode is needed by some PC ports. Up until now this cable has only worked on some computers due to a design bug (Thnx go to Scott Kroeger for finding it. :) It *should* now work on most computers. Here's a schematic for connecting your GameBoy to an IBM-PC Parallel Port for exchanging data. NOTE: ONLY GB BASIC CURRENTLY MAKES USE OF THIS CABLE.

GameBoy Link Port Output Format

Here's assembly code, a timing diagram, and a circuit for controlling external projects with a GameBoy. You can add as many digital outputs as you want to this port.

GameBoy Link Port I/O

Here's a circuit for controlling 16 digital outputs & reading 16 digital inputs with a GameBoy.

Adding a Game Link to a Super GameBoy

The idea came from a web page in Japanese, so the original credit goes to the authors of that page, Papa and Shaora, as they are the ones who figured out that it would work. You may want to check out their page for the pictures.

Misc Hardware

Tamagotchi Pics - Photo #1 - Photo #2

Here are photos of the latest version of Tamagotchi for GB. This version is ONLY sold in Japan. (Earlier versions of Tamagotchi for GB sold in Japanese & English are normal carts that don't operate when the GB has been powered off.) It contains a battery & a speaker to allow it to make sounds when it wants attention even when the GB is powered off. Photo #1 shows the internal layout of the electronics. Also in this picture is a standard GB cart for size reference. Photo #2 shows the cardboard box & plastic case in which the cart was sold. In the middle of this photo is the underside of the top half of the cart. It holds the small speaker & the battery.

Demo Boy II Pics - Whole Setup - Main Board Zoom

Here are photos of the GB demonstration electronics used at many stores that sell GB games. This is what drives the television often used for display purposes. Here is a list of ICs used in this unit.

Jeff's GameBoy Robot - 'CyberWeasel' - Top View & Bottom View

Here's my GameBoy robot! The mechanical kit I got from lynxmotion. For electronics I used a GameBoy Pocket, a game cartridge with SRAM (and the ROM removed), the GameBoy I/O Example, Robot Power/Servo Schematic and a 27C256 eprom running GB Basic. The eprom /CE is supplied from the GameBoy I/O Example. Even though I've already programmed it to move small objects around, basically this is just the starting point for more advanced electronics. Notice that there is still plenty of space underneath for future electronics expansion.

Sharp LH534/LH538 ROM

This is the ROM used in most all ROM+MBC1+RAM carts for GB (LH534) and the ROM used in Game & Watch Gallery 2 for GBC (LH538) among others.

Samsung KM23C16/32/64000 ROM

This is the ROM used in the Zelda DX cart.

74HC595 Equivalent Circuit

The Rewired Mac 512 Keyboard schematic contains a 74HC595. Since this may not always be easy to obtain, here is an equivalent circuit using easier to obtain parts.

GameBoy I/O Example, Rev B

Here is what I use to do I/O on a GameBoy. The main chip is an 82C55 that allows you to do digital input or output on up to 24 lines. I make space for it by killing ROM access from 7FF8 to 7FFF and putting the I/O addresses here.

GameBoy Robot

This robot was designed by Jack Davis. He is the one that talked me into adding the SERVO command to GB Basic. This is the first draft of a small robot he's making.

Rewired Mac 512 Keyboard

GB Basic supports this external keyboard schematic that connects to the link port on the GameBoy. You can rewire any keyboard. A Mac 512 keyboard is just what I had handy. If a 74HC595 is difficult to obtain, this 74HC595 Equivalent Circuit will work just as well.

Super Smart Card Base Unit Schematic

This is the schematic for the SSC base unit that I own. I have been told about a different design base unit that doesn't contain an 8751 microcontroller, but I haven't had a chance to see one yet. This schematic is for educational value only. I do not have a copy of the code required to be burned into the 8751 in order for this circuit to work.

Super Smart Card Schematic

This is the schematic for the SSC. I drew this thing not for the intention of copying their design, but because mine has gone into lockup mode and I just am trying to do everything possible to get mine working again. It has always been kind of 'flakey' in programming correctly and now it won't program at all. I am not sure if this is a problem in the base unit, SSC, or the IBM-PC software at this time.