JonSharp.net:70:projects:gameboy_ethernet
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# Gameboy Ethernet Project

## Overview


The goal of this project was to allow a Nintendo Gameboy Color to
function as a remote reporting tool via a standard Ethernet
connection. This was accomplished using various hardware. Using a
custom built RS232 convertor circuit, the Gameboy connects to the
serial port of a special Java embedded device named TINI. The TINI
hardware also includes an Ethernet interface, making the TINI
essentially an Ethernet-to-Serial adapter. The TINI establishes a
socket connection with our Java server which sends useful information
back to the TINI which sends the output directly to the Gameboy’s LCD
screen. Read the following sections for the details of each
component.

## Hardware

 - Nintendo Gameboy Color
 - Dallas Semiconductor's TINI
 - RS232 signal convertor circuit

## GB Software

The Gameboy software was written in assembly language (The Gameboy
has a Z80 workalike CPU.) and assembled using Rednex Gameboy
Development System. RGBDS The assembled ROM image was then flashed to
a 4Mb Bung flash cartridge via Bung’s GB Xchanger. The original
design and code are Ken Kaarvik’s. Many thanks go to Ken for the
inspiration for this project, his code and permission to expand on
his very excellent idea. The original code was once available on
Ken’s page -- not sure if it still is.

Source - commboy.asm

Full project zip

## Java Client

The Java client code runs on the TINI, providing the Gameboy with the
connection to the Java server running on our Linux workstation. The
client code begins by creating a serial port object and opening it.
Then it opens a socket connection to the Java server. When the server
sends the information to client, the client then outputs directly to
Gameboy over the serial port. This is a simple application providing
the Gameboy an Ethernet interface.

Source - GBClient.java

## Java Server

The Java server is on a Linux system and remains open to connections
while running. The server waits until a client connects and then
sends out system information such as uptime and cpu temperature.

Source - GBServer.java

## Project Notes

Many things were required to pull this project off. First, we had to
learn assembly for which McKee Library proved helpful. Then we had to
learn about the Gameboy’s hardware. The Internet is full of great
resources for that. The MAX232CPE circuit was constructed in under 3
hours. The TINI we used is running TINI Firmware 1.01. In order to
allow our Java client software to execute without invoking it
manually, (telnet over the Ethernet device) we had to add a line to
Slush’s (TINI’s shell) /etc/.startup file. All coding was done using
Vim.

Special thanks to Dr. Halterman for his help in this project! Here
are some of the project costs:

 - TINI w/ board - $75
 - Gameboy Color - $70
 - Bung Flash cart and Xchanger - $90
 - Parts for RS232 circuit - ~$15
 - Hours of mad coding - priceless

## Pictures