As I’ve mentioned before Semicom was one of my favourite Korean arcade developers. While Semicom games are often a bit rough around the edges, and borrow ideas heavily from others they were original products and for the most part are playable.
Hammy found he had a Cookie and Bibi 2 PCB that is actually rather interesting, because it seems to be an earlier and generally forgotten version of the game; I don’t like to use the word prototype, since it probably isn’t, but it definitely seems to be rarer than the more common version that was already in MAME. The giveaway that it’s an earlier set to me is that it uses the old style Semicom logo, as found on Hyper Pacman, rather than the newer Semicom logo found on the later games. Most of the backgrounds are also different. Test mode is also even more incomplete (not that it is complete even in the set currently supported, Semicom often just didn’t bother to finish the test modes)
One of the other interesting changes is the screen positioning, the newer version that’s already in MAME has the screen more centered, moving most of the important graphics up by 8 lines and placing the image in the center of the black borders, rather than leaving 16 blank lines at the top. Strangely the title screen background wasn’t re-positioned in the same way, probably an oversight by Semicom.
The other obvious change at surface level is the older set will do 1P vs 2P versus mode on a single coin.
The game also expects different protection data, meaning it has different MCU content, I’ve faked this for now but we need to verify it.
Overall this is a very significant revision and clearly shows the game at an earlier point in development.
Here are some comparison shots, with the existing MAME set on the left, and the set Hammy dumped on the right.
So yes, that’s a nice little piece of history.
I’ve also been working on emulating the Radica ‘5-in-1’ Space Invaders TV Game. It’s a 6502 based device (that doesn’t appear to be a NES clone) but has some very weird video hardware, and might have a custom CPU core as the way the interrupt vectors work is non-standard. So far I haven’t managed to work out how the graphics / sound actually work for most of the games, although you can see it is running the menu, and you can just about recognize Space Invaders. Weirdly the graphics are all stored in ‘pages’ that are 256 pixels wide, rather than as tiles, but the game appears to have tilemap like structures in RAM. It might be there’s a DMA operation that converts the formats.
One of the games in the collection is Qix, which handles video in an entirely different way, writing directly to a framebuffer.
There are plenty of reviews of this device on YouTube, including some with decent quality footage captured from the original hardware such as this one which will prove valuable for testing / reference.
What’s interesting is that the Radica Tetris unit looks like a similar piece of hardware, and according to Sean Riddle, who is dumping these things, contains the same CPU die in one of the globs (which are used instead of real chip packaging) and also contains what looks like a ROM glob with the same pinout as the Space Invaders one, however unlike the Space Invaders one it lacks a 3rd glob. My theory at this point is the 3rd glob is actually dedicated RAM / framebuffer just for Qix to use. Hopefully I’ll have a dump of the Tetris one to look at soon as it might allow me to make more sense of this Space Invaders one.
I do wonder if there were any other Radica TV games based on the same technology, obviously the Genesis ones are just cloned Genesis hardware, but there are a lot of other Radica products and they’re exactly the type of thing MAME is well positioned to be emulating.