Today, the whole thing goes a bit further, I finally take a bit of time to look on the signals on the WonderSwan Cartridge bus, especially on the BMC signals. I think I solved the whole mystery!
Saddly, the NVidia 8600M GT of my main computer decided to die last Saturday, so I’m nearly computer less actually, and my project can’t follow the path I wanted. I can only work a little on my project during my work time. (Yes, that’s not a good thing to do, I know ;))
The original thread on Wonderswan development (in french, sorry): Développement Wonderswan (le retour) « Pocket Videogames – yAronet – Attention : forum addictif !.
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.
Today, I played with my Arduino to connect a Yamaha YM2149 ( know too as AY-3-8910. After some times I finally got it to work !
And contrary to all other works I saw, I didn’t use an external Quartz, the 2Mhz clock I used is generated by the AVR chip.
Since it was not buyable, and I need it for other project (like the AC2012’s SpeedCoding party this Weekend) I made my own version of the SD2SNES board from the source given by ikari01, the author of the SuperCIC and so the SD2SNES.