Tag Archives: Wonderswan Crystal

WonderMadeleine code release

Ahoy WonderSwan users, developers and hackers!

The WonderMadeleine HDL code is available on the treasure island of GitHub. That’s some treasure chest you’ve got there.

(sorry for the pirate speak ;))

So yes the HDL code for WonderMadeleine is now available, to fit in the Altera EPM240T100C3 MAX II CPLD (a TQFP100 CPLD so not too big and easy to solder)

There is currently no support for external EEPROM, RTC of GPIO, but they will come shortly, I need to finish the documentation on how to access them from the IO port as current documentation is merely wrong. I’ll also publish a more correct hardware documentation at the same time.

This HDL code is currently licensed with the CC BY-ND-NC 4.0 license, that mean that

  • You cannot take CPLDs, burn them and sell them
  • But you can create your own cart and use the CPLD burn with the code, and you can sell the game cart you made using this CPLD (as you are not making profit from the CPLD, but from your game)
  • I’m currently not fond in allowing fork of this project until it is fully finished, but I will be really happy for patch proposal for supporting another CPLD or correcting bugs
  • And you can’t integrated this code in a larger project. that mean that you can’t integrate it with other HDL code in a bigger CPLD or FPGA.

Some of this limitation may change in a near future, but they are applicable at the time this line as been written.

I may provide in a near future a template board, either only the borders for a board that fit in existing cartridge, or even a basic board with the Bandai, Flash ROM, SRAM and save battery, depending on people’s need.

I hope that this project will help the WonderSwan homebrew scene grows as it deserve it. This game console is just an unknown jewel.


Ten years ago, two student from the Cornell University (North Australia) released the first public homebrew cart and software for the WonderSwan that does not use the WonderWitch. See here.

Their project was a major breakthrough as they where the first to document the WonderSwan hardware, and they are the original authors of the well known wstech document.

And after they made their release… nothing more. There were no concrete or public hardware development for the WonderSwan that went to a releasable product.

Until today!

Continue reading Finally…

Splash’s WSC_TECH documents

Around one or two years ago a website with exclusive information on the WonderSwan disappear, I’ve manage to contact the author, the original server had a HardDrive crash, but he manage to restore some part and put them on another website. So here are the wsc_tech documents:


I have some sort of a copy of the wsc_tech1, it’s the IO mapping. I will eventually post it here soon.

Second update on WonderLyzer

I’m sending right now the data to process the batch of PCB, due to some test (printer’n’paper test are the best thing to do!) I found that I stupidly use the width of the internal cartridge PCB instead of the cart itself, and found out that the PCB was going more than expected in the swan, so I do a small modification on the PCB to use a more accurate width, and add a T shape like on top to support more the cart connector, and adding a small surprise on this part.

Continue reading Second update on WonderLyzer

Wonder Project!

 A few month ago, I was speaking with friend about the marvelous Bandai’s WonderSwan, about making something that is missing for now on the platform: Flash Carts.

But before going more on the subject, I will give you some clues on the WonderSwan, and why it can be so attractive, even if it didn’t went out of Japan.

The WonderSwan is the last video game console made by Bandai, and it was at first a project of Yokoi Gunpei just before his tragic death. This handled game console was in direct line with the Gunpei’s leitmotiv: “Lateral thinking of obsolete technologies”

All his life he try to make the cheapest possible device, without lowering the quality, and this by using “old” technology and by finding a new way to use them. The Wii Remote, is an example, but the GameBoy too, or even the Nintendo DS, they use “obsolete” technology in them, but with modern goal.

There is too much to say on this and could make a full article, but the WonderSwan was made with this idea. When you look at the specs of the CPU of first model, a NEC V30MZ (a clone of the 8086), and when you think that the first WonderSwan was out in Japan in 1999 this look a bit old. But this come at a big price: the device cost was awfully low compared to competition, it was sold at ¥6800 (~$60 / ~50€) when the GameBoy Color cost at least the double or the triple. The other major advantage of the WonderSwan was it’s autonomy: ~30-40Hr … with only ONE AA battery!

The first model was only black and white, like the original GameBoy, and two other version come later, the WonderSwan Color (2000) and the WonderSwan Cristal (2002) with for both a color screen (241 color out of 4096) more RAM (512KB) and for the later a better screen: a TFT LCD instead of a FSTN one used on previous models.

All of thoses models comme in multiple standard colors, and it is, maybe, the video game console with the most special edition I ever see.

So our main problem here is that the WonderSwan use, on each cartridge, a custom chip named Bandai2001 or Bandai2003 and some of its function are still unknown.

Continue reading Wonder Project!