What's wrong with the GBexx card?

Below, you see the third edition of the GameBoy bus extender. The previous edition was not bad, but had some minor difficulties incorporated. I mention:

Issue 3 of the GameBoy Extender card

Here's why I redesigned the GameBoy BusExtender GBexx:

If you click the image above, you get a full sized (150 dpi) png file with the GBext3 circuit. In the download section are the Eagle schematic and the Eagle board files.

GBext3: the printed circuit board

And this is the routed printed circuit board. The board is double sided. I could have done it with wire bridges but a double sided board offers more freedom. And now the holes are easier to circumvent. Additionally, now the 34 pin connector can be mounted on the topside (where the connector and the chips are) and hence the pinnumbers are not jumbled up anymore.

The board contains the same three 74HCT245 buffers and the new 74HCT243 buffer which replaces the 74HC14 hex inverter. A small LED is mounted to get some visual feedback in the prototyping state. It indicates whether we have power or not.

This board was made with the Gameboy library of the Eagle CAD package. It contains a GBC connector (made up of contact fingers). This made life a lot easier when making the drawing and when routing the tracks.

Page created 27 November 2006,