January (part 6)

Of all the XaviX based TV games I’ve covered this one has to be one of my favourites. It’s another game from Epoch, and it’s a trackball based title called ‘Super Dash Ball’

Like Gururin World, the designs found here feel very heavily influenced by Sega. With Gururin World there were the Sonic-like loops, here you’re rolling a blue (or red) ball at breakneck speeds along winding courses meaning it feels like a mix of Super Monkey Ball, Sonic’s Special Stages, and Fantasy Zone (especially the backgrounds) Both games rely on speed etc, and while not having to use a trackball does take some of the challenge away from this one it’s still an enjoyable game, especially against another player. There are so many nice little touches with this too, including the marble pointers used for the menus being able to collide with each other. There are some visual glitches with the edge of the screen during the ‘road’ rendering on corners, but best I can tell those happen on hardware too, and are a limit of what seems to be a common rowscroll / road engine; Dirt Rebel MX exhibits the same thing. The trackballs are mapped, and this one is fully playable in MAME, including the minigames.

All the recent dumps have also made one thing quite clear, there are 3 main revisions of the XaviX hardware, the ones with the die marked either SSD 97 or SSD 98, the ones with the die marked SSD 2000 (which adds more opcodes) and the ones with a die marked SSD 2002, which is presumably what SSD called Super XaviX, as it also adds a bunch of extra video modes (such interlaces screens and bitmap support) and possible even allows them to be of a higher horizontal resolution than the rest of the screen.

Emulation of that later hardware is preliminary, as there is currently a lot less evidence in terms of software available for improving the emulation, and a lot of what is available relies heavily on custom controls, or has other annoyances such as larger ROMs that presumably have some kind of fancy mapping as they don’t fit in the usual XaviX memory map.

XaviX Bowling is one game using the 2002 chip. As you can see only half the background is shown, suggesting that it either gets scaled, or output at a higher resolution. The sprites also flicker heavily (and the screen jumps up and down, because the hardware does interlace by outputting a different field each frame – making that look good will be difficult to say the least) This uses a ‘camera’ with 32×32 cells to track the ball, a bit like the Lord of the Rings and Star Wars games, emulating it will probably be difficult. It also dies after a while with an SEEPROM error, because there is definitely something messed up with either the i2cmem code in MAME, or the way I’m hooking it up (many XaviX games suffer from issues with it, it’s the reason I’ve been unable to promote Dirt Rebel MX to working)

XaviX Baseball is another using the 2002 type chip, and again suffers from similar problems.

These XaviX sports games actually run on the XaviXport ‘console’ which is basically a fake console because all the game hardware (CPU, RAM, Video, Sound etc.) is in the carts, and the controls are the peripherals, the console just acts as a TV adapter. This means you have cases like the Bowling where the cartridge has the camera on it too. Other games has other things, Bass Fishing has an RF Reciever and expects the Rod to communicate with it (presumably the Rod has its own MCU etc.) Without attempting to simulate that it doesn’t get very far.



XaviX Boxing is another with a camera, but either sits on a black screen, or if you init the EEPROM, fails to read properly and shows an error.



Jackie Chan J-Mat Fitness also has EEPROM issues. This game also has a larger ROM size of 16MB, so will likely cause me issues later.

Decathlon in France actually released their own version of the XaviXport under the name ‘Domyos Interactive System’ The main difference is that this one is for the PAL region and had an entirely different set of games (the games explicitly check that, and jump to a dead loop if the region is incorrect, with some of the XaviXport ones doing the same if they detect PAL, meaning the cartridges can’t be used with the wrong system)

The Domyos games that are dumped all have issues with the EEPROM hookup (although seem happy to boot after initializing it) and also display corrupt graphics, because they use the 16MB Rom Size, and presumably need me to figure out the proper mapping in such a case (we think the dumps are correct at least.) Fitness Challenge and Fitness Exercises look like this, and crash after the last shot, again presumably because they’re getting bad data due to bad ROM mappings.

The Domyos games also had one further surprise for us. Remember I said the system was a ‘fake console’ where all the hardware was in the cartridges, well, the later games swap the CPU for something else entirely, probably what is known as ‘XaviX 2’ which is an ENTIRELY different architecture, not 6502 based at all from what I can tell so far. Needless to say, those ones do nothing in MAME, we haven’t even managed to identify what the CPU is derived from, it could be an original instruction set, and needless to say that would make things exceptionally tricky. Domyos Fitness Adventure and Domyos Bike Concept at least fall under that bracket.

There was another XaviX 2002 type game dumped, and that was a random Thomas the Tank Engine unit, which I honestly wasn’t expecting to be 2002 type at all. It’s a standalone TV game from Japan, although in emulation for some reason it seems to get stuck just before drawing the full title screen, everything is animating but not moving forward, don’t know why at the moment.

So after a rather anticlimactic end to this part, yes, there will be a part 7 (did I mention that January has been busy?)