SpritesMind.Net

The Megadrive had four 15/16-color palettes (one color from each palette is used as transparent, but it can be used to color the backdrop) for a total of 61 colors onscreen. So basically each sprite can only use 15 colors and each background tile (8x8 pixel square on a particular background plane) c...

Any 68K assembler that can produce a raw binary output can be used.

Are you decoding or just conecting the segments to random lines? I think it's just hardwired to display Sega (or as close as you can come on such a display anyway). My Genesis has a minor modification which allows me to disconnect the /CART_IN signal (useful for dumping), but my wiring came undone ...

There's not a lot you should do mid-screen. The manual doesn't mention the HBLANK explicitly but if it's the same transfer capacity mentioned for active scan then that's worth about 8 or 9 palette entries. When I was screwing around with Raster F/X I was able to turn off the display (required to pr...

The problem with this kind of render is that while you are updating via DMA you can't do anything else. Less of an issue on the Sega CD of course, since presumably the bulk of the processing on the faster Sega CD 68K. If you move from 40 cell mode (320x224) to 32 cell mode (256x224), you lose some ...

As far as DOOM goes, yeah, I suppose RAM limits would be a problem. I wonder how much a typical level takes? I'm sure the BSP and the textures are the bulk of it, but exactly how much? How does 32X DOOM deal with only having 256KB of RAM? I've never messed around with the guts of DOOM, but I'm goin...

heck, even Super Street Fighter II only pushed it to 6MB with bankswitching on the cart. Actually, it was only 5MB, but the problem is probably one of ROM cost than ability to access more space easily. I would think the limited RAM available in the 32X would make a 32X/CD DOOM port difficult though...

Heh, I have just the document with you. See this page: http://www.retrodev.com/segacd.html Start reading where it says "General" You can use the program BuildSCD from the same page to take care of putting together all the headers for you, or you can write some macros for your assembler. In either ca...

To be honest, I don't remember. You might end up locking the VDP though and even if it has no negative effects it's not needed for Sega CD programs.

For a small program like this you usually need to do the following:

Change the start address to either $200000 or $FF0000
Remove ROM header and TMSS check
Hook V-INT (if present) using a BIOS call
Adjust DMA commands if DMA-ing from Word RAM ($200000) to deal with a small hardware bug.

The only problem I am seeing though, is a way to get the Genesis to read the thermistor (the resistor that tells temperatures).. I got the ratings for this specific thermistor, but how can I wire it up to the Genesis controller port, to actually read it? I don't see how something varying in resista...

I might be misremembering, but doesn't /YS have something to do with the priority flag? Basically, if the current pixel is a high priority pixel it's high, and if it's a low priority pixel it's low (or vice versa). I believe the 32X uses this to properly overlay it's video with the output of the Gen...

Most VGA monitors will not sync to the 15KHz signal; however, some LCDs will (presumably because some LCDs also have TV inputs on them).

MOD, yeah, there is no documentation about the megacd boot... Does the 32x shift the mapping when turned on when in megacd mode, that would be double insane ^^? Well it might remap the cartridge port from $400000 to the 32X banked address, but unless you've got some kind of crazy cart + CD combo ga...

They're electrically compatible in the sense that the Saturn controller port and the Genesis controller port are both 7-bit bi-directional I/O ports. Unfortunately, the protocol is different so a Genesis game won't know what to do with a Saturn controller. You could support them in code you write ho...