Other than to play Virtua Racing of couse. :P
I've heard others propose turning it into a RAM cart for Sega CD but would prove difficult. Anything else?
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Other than to play Virtua Racing of couse. :P
I've heard others propose turning it into a RAM cart for Sega CD but would prove difficult. Anything else?
a pass-thru cart for the SVP ;)
drill a hole in it and use it as a Gangsta' medallion
Repurpose the SVP chip and have the likes of Chilly Willy, tomathiest and TmEE develop a game using the chip, because they can do............anything. :D Maybe use it in a manner like the SNES used the SFX2 chip for "Yoshi's Island". How's about it guys?
That's what I was hinting at, though I think most people prefer to use the 32X as a base. Then again, you'd get some nice street cred if you made a homebrew game using the SVP. :D
Use it to help keep track of your collection/inventory of used crochet doilies :D
Give Sonic REAL Blast Processing. ;)
Add scaling and rotation to games without the use of a Sega CD?
Exactly.Quote:
Originally Posted by m68k
Extra parallax scrolling layers in platforming games!
What exactly does that chip do, anyways? Besides slicing, dicing and blending, of course.
It also makes bread.Quote:
Originally Posted by The Sports Guy
Yeah but if you have a 32x then your screwed because the SVP chip messes with the 32x and keeps it from working.
It walks the dog, makes your dinner, and visits your elderly grandparents in the nursing home! :lol:Quote:
Originally Posted by The Sports Guy
Seriously, it's just a DSP. What makes it really useful for the Genesis is that it has 128KB of DRAM that can be read directly in "cell" fashion by the Genesis, allowing you to generate a bitmap using the DSP, then use the Genesis DMA to copy the data directly to the VRAM without any further processing needed. Even if you didn't use the DSP itself, that DRAM would be useful for a ton of different games, notably 3D-ish type games.
You could use the SVP for higher than normal real-time decompression for 2D type games. In audio, the SVP could decompress audio into 32KB for the Z80 to playback. It could also be used for decompressing video. The thing has all kinds of uses any kind of game could take advantage of. It's limits are the programmer's skills. Well, that and how much DSP code you could fit in the DSP program RAM. :D
I was wondering if the 64KB RAM present in the Mega Drive can also add to the 128KB present in the VDP cart? You know, to give it 192KB of Program RAM? Or is it like the 32x where it can't access the Mega Drive's RAM?Quote:
Originally Posted by Chilly Willy
And you forgot about the Genesis color palette.Quote:
Originally Posted by Chilly Willy
As far as I know, the SVP can only access the rom and the DRAM on the cart (both are directly connected to it). There doesn't seem to be any facility for accessing any Genesis hardware. The SVP is a dedicated slave peripheral. It's code is located at 0x800 in the cart rom, and it has it's own internal ram as well of the external 128KB DRAM.Quote:
Originally Posted by Jasper061992
If you mean 192KB for the Genesis, that's possible. The Genesis can access the DRAM directly, and in a couple other locations that rearrange the data into cells very much like the Word RAM of the SCD.
Yes, that's also a limitation, much like the SCD has to put up with.Quote:
Originally Posted by Da_Shocker
Well, there's this: http://sega-16.com/forum/showthread.php?t=7765 ;)Quote:
Originally Posted by Guntz
Hmm, the last time I brought up scaling/rotation functionality in the context of the SVP (in the above thread I mentioned) I got in inconclusive response. (then again, I was being pretty vague and I didn't want to press the discussion on that any more at the time) Specifically you mentioned that the SVP wouldn't be very useful for rendering something like Wolfenstein as I recall. (I got the impression that a more general puropose MCU would be more useful opposed to a DSP)Quote:
Originally Posted by Chilly WillyExactly.Quote:
Originally Posted by m68k
So would the SVP be useful for scaling immages like the Sega CD (for Space Harrier/After Burner like stuff -though I seem to recall Batman Returns using some more complex for the buildings in the racing levels).
Could it be useful for generating a scaled/warped BG tile (mode 7 like) as with the special stages in Sonic CD, Some levels in SoulStar, BC Racers, F1 Beyond the Limit, etc?
Is it really DRAM and not PSRAM? (with external refresh circuitry -or I suppose the SVP could have included refresh circuitry onboard in addition to the DSP core)Quote:
Originally Posted by Chilly Willy
The 15/16 color limit is notable, and of course the 9-bit RGB palette is another limitation in addition to that, but I think they could have done a bit better looking than Virtua Racing in color terms.Quote:
Originally Posted by Chilly Willy
Star Fox and Vortex on the SNES use only 16-color tile layers (both run in mode 2 which is rather close to the Genesis with 2 16-color tile BG layers plus sprites) both use a polygon layer overlaid ontop of a 2D BG. (along with sprites for some things liek the status screen)
Now the SNES has the advantage of the 15-bit RGB palette to index from and the 8 BG subpalettes in addition to 8 spr palettes, the polygon layer only apears to use one palette on screen at a time though, so a simple 4-bit bitmapped display (15 colors plus transparent), however, both games seem to use dynamic palette selection to optimize for whatever is on screen coupled with varying amounts of dithering. (I'm not sure if the 8 BG palettes are fixed and a selection is made from among those, or if subpalettes are changed as well -changed between levels if nothing else)
The Genesis would still me more limited with only 4 global palettes selected from 9-bit RGB, but the dynamic palette selection and variable dithering should still be helpful.
There are other 3D SNES games which do use 256 indexed color modes (8-bit pixels), Doom, Stunt Racer FX, Dirt Trax FX do, plus Wolf3D uses a 14x12 tile mode 7 layer for the display -plus sprites for the status characters and on-screen weapons. (scaled to 2x, so effectively a 112x96 screen)
No, I said that the SVP wouldn't be very good for the game code. DSPs are lousy for game code. If all you did was only the rendering on the SVP, it should be fine. A DSP really isn't the best processor for that either, along with rotation of scaling, but you can make that work better with the faster DSP than on the 68000. The best split would be to put the game code on the 68000 while the SVP does the scaling, rotating, or spans/columns for a Wolf3D type game. So while it wouldn't be IDEAL, it's still useful, which is really all you need here.Quote:
Originally Posted by kool kitty89
You can do all that with it. It would probably be faster than on the 68000, but not as fast as it could be if you had hardware dedicated to those operations.Quote:
So would the SVP be useful for scaling immages like the Sega CD (for Space Harrier/After Burner like stuff -though I seem to recall Batman Returns using some more complex for the buildings in the racing levels).
Could it be useful for generating a scaled/warped BG tile (mode 7 like) as with the special stages in Sonic CD, Some levels in SoulStar, BC Racers, F1 Beyond the Limit, etc?
Yes, it's DRAM. A Toshiba TC511664BJ-80 to be exact. That's an 80 ns 65536x16 bit DRAM. You can find the datasheet here: http://www.alldatasheet.com/datashee...1664BJ-80.htmlQuote:
Is it really DRAM and not PSRAM? (with external refresh circuitry -or I suppose the SVP could have included refresh circuitry onboard in addition to the DSP core)
I'm sure the refresh is built into the SVP. The SVP on the card is not JUST an 1601, it's also got the extra hardware needed to interface to the DRAM, the ROM, and the Genesis cart port all in one package. It's a SEGA custom part (number 315-5750) made for them by Samsung.
Thanks for clearing that up, that makes a lot more sense.Quote:
Originally Posted by Chilly Willy
Ah, so similar to the chips used in the Sega CD and 32x for the framebuffers. (not sure if those were Toshiba, but definitely 16-bit 128 kB DRAM chips -though I think the CD may have had a 512 kB chip too rather than 6x 128 kB chips)Quote:
Yes, it's DRAM. A Toshiba TC511664BJ-80 to be exact. That's an 80 ns 65536x16 bit DRAM. You can find the datasheet here: http://www.alldatasheet.com/datashee...1664BJ-80.html
Yeah, I knew it was a custom chip using the 1601 core, I didn't know about the refresh, but it makes perfect sense. (I wonder if Nintendo did that for the Super FX GSUs or SA-1)Quote:
I'm sure the refresh is built into the SVP. The SVP on the card is not JUST an 1601, it's also got the extra hardware needed to interface to the DRAM, the ROM, and the Genesis cart port all in one package. It's a SEGA custom part (number 315-5750) made for them by Samsung.
ftw:!:Quote:
Originally Posted by JDB1983
Actually, if you take the PCB out of the case, it already has two holes in it you could put a chain through. :DQuote:
Originally Posted by OldSchool
it looks cooler too that way ^^
if its complete with box and manual i know a good use for it.
Lets just say it involves a box, stamps and my address.
I would so do that with one of my Genesis games and wear it to school. :PQuote:
Originally Posted by Chilly Willy
...or my shit-tastic Rainbow Six GBC cartridge.