The FPGA Videogame Console


PAGE 6





Cheetahmen 2 uses the same mapper as the Action 52. Yeay!




Gawd, what a horrible horrible game it is too.




Continuing on with the multicart theme, I got the Rumble Station mapper going. This is that blue hand held NES unit with the 15 Colourdreams games on it. I have an odd fascination with their games for some reason.




Secret Louse. Yuck.




Yeay! Master Chu and Drunkard Hu.




In game of the same.




After doing all that stuff, I decided to finally crack Mapper 90 wide open and implement it. Its IRQ counter is REALLY complicated, and I had to make some special hardware to do it. I set up CopyNES to hack on it all night, and came back the next day to dork with it. Finally, I cracked it and implemented it!




The Aladdin pirate is pretty well done, but like most other mapper 90 games, the music is HORRIBLE. Mapper 90 was the most complex mapper I have implemented up to this point by a long shot. I spent 2 days designing it out and debugging it.




The infamous Super Mario World pirate. This is of course another mapper 90 game. Without the proper IRQ timer stuff, this game doesn't work right.




The first world.




World map. Note: some extranious "crap" can be seen around the edges of alot of games. This is normal and does not indicate a problem with the console. A regular TV cuts all this stuff off, since it's technically in what's known as the "overscan". The top 8-10 scanlines and the bottom 4-5 are usually not visible, and around 6-8 pixels on either side are missing too. The top scanline on the screen is the first "junk" scanline the PPU renders and is not visible. I do not blank it, so it shows up as the background colour.




Tekken 2. I actually have this cartridge, and I used it to extensively reverse engineer mapper 90. I poked and prodded it with CopyNES and Bankwatch until it surrendered its secrets.




The little intro thinger is kinda nifty.




I can just hear that trilly nasty "mapper 90 music" right now looking at this pic.




Yeay! MK3 special 56 peoples! Like a couple other mapper 90 games, this one responds to dip switches present on the board (more like shortable jumper pads). Manipulating these pads results in the title screen totally changing, so the pirates can make 1 board and 1 game and sell it as 2 or more different games. Clever.




This is the same as the previous game, just an alternate title screen using the jumpers.




In-game doesn't change, just the title screen and other superficial things.




Part of the intro sequence.




In-game again.




This game uses ROM nametables, so without that working, the intro screen is all hosed up. Getting those working results in this game operating properly.



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