2.0 The Project Idea

The idea is to connect other devices to the GameBoy^TM. Usually this can be accomplished by using standard input/output interfaces called ports. These ports are 'pins' to connect external devices to data-, address- or control-buses. The parallel port should be accessed as easily as a RAM or ROM, to keep programming simple.

2.1 What is missing in the GB-hardware ?

The GameBoy^TM already has a serial port which could be used if there weren't two major problems. The first is that the data flow-rate on serial ports is slow. The second is that the 'game-link port' does not seem to support any standard protocol for data interchange. Further there is very little documentation on this 'link port' (see gbspec.txt)

This best performance for connecting external hardware is achieved with an 8 bit  parallel port. This is the basic idea which will be discussed in paragraph 3.0 Building the hardware.

Figure 6: GameBoy with adapter & ROM