Super VDP for SegaCD

[tomaitheous]

Then what's with these comments about the ASIC being limited by the Genesis VRAM?

The speed. You can't very well upload a whole frame (screen) of bitmap arranged tile data to the VDP in a single Vblank. If you could, you'd get 60fps. So you're stuck with two methods; 1) write multiple passes to VRAM with multiple vblanks, but you would see the screen updating in realtime and it would look like a chunging FPS with vsync off. 2) use a double buffer in *vram* so that you could write to off screen tile section, in multiple passes still, but *without* seeing the updating process onscreen (tearing). Still slow, but no tear. Side effect; you waste a LOT of vram doing that. Possibly 80-90% vram space, so little is left over for sprites or other stuff.

Method 2 eats up double the vram, but method 1 still eats a nice chunk of vram as well.

Nothing you do is going to add VRAM to the VDP. The whole point of this thread was that the ASIC would be better off paired with the Super VDP and a DMA chip.

And for what it's worth, I'm told that Batman Returns driving parts max the bandwidth of the ASIC. But then again, is simply doing non scaling/rotating overlaying on the ASIC faster? One could assume so.

Thinking out loud; maybe it's possible to use the ASIC to do some nice 16color x 16subpalettes (with some limitation) for sprites for the 32x Super VDP. You do a two pass system. One pass would be the actual pixel data (16color/4bit) and the other pass (and other separate buffer) would be the palettes for those pixels (16 subpalettes). It'd treat the separate as 4bit pixel data, but the 32x cpu would decode it as palette association. A palette mask

[Chilly Willy]

Thinking out loud; maybe it's possible to use the ASIC to do some nice 16color x 16subpalettes (with some limitation) for sprites for the 32x Super VDP. You do a two pass system. One pass would be the actual pixel data (16color/4bit) and the other pass (and other separate buffer) would be the palettes for those pixels (16 subpalettes). It'd treat the separate as 4bit pixel data, but the 32x cpu would decode it as palette association. A palette mask

I was thinking of doing tests like that once I've got my CD code running, but my idea was plain eight data done in two passes - doing the exact same thing, but on different nibbles of the byte for 256 color data. I do like your idea of one pass being the color, while the second pass is the "palette" selector. Hadn't thought of that. It would make it very similar to the SNES graphics. You could probably quickly fill a square with the palette data, then do the scaling/rotating for the rest.

[kool kitty89]

Wait, don't you still need the word ram to comunicate with the Genesis CPU as well? (though in the proposed layout with the Super VDP, you'd only need to do so for reading controllers, using the genesis audio hardware, and if you wanted to have the Genesis displaying a seperate video layer like in the genesis/32x configuration)

If the word RAM was broken into 2 128 kB blocks, would you be able to use one for comunication with the genesis while the other can be used by the VDP. You'd only need 128 kB to double buffer with 256-color 320x204 anyway, right?


What about the added CPU in the CD, tomaitheous was commenting (toward the begining of this thread, and I think in a couple other discussions as well) that it wasn't really necessary and kind of overkill for the system. OTOH, how could you replace it? Use the Genesis CPU instead? (would that be possible?) And if you did so, wouldn't it make generating an additional genesis graphics layer less practical as well?

Or was the CD's 68k really an asset for the console?

[Chilly Willy]

Wait, don't you still need the word ram to comunicate with the Genesis CPU as well? (though in the proposed layout with the Super VDP, you'd only need to do so for reading controllers, using the genesis audio hardware, and if you wanted to have the Genesis displaying a seperate video layer like in the genesis/32x configuration)

The Word RAM is mainly used to pass video data to the Genesis side for display. The communication registers in the ASIC are used for passing small amounts of data. The Word RAM will also be used for passing code/data to the Genesis, but that's normally just at the start. The code/data will get copied to the Genesis Work RAM, and then the Word RAM will again be used for video data. So it has more use than JUST video, but that's it's main use.

If the word RAM was broken into 2 128 kB blocks, would you be able to use one for comunication with the genesis while the other can be used by the VDP. You'd only need 128 kB to double buffer with 256-color 320x204 anyway, right?

If there had indeed been a VDP inside the CD, I don't see the need for changing the way the Word RAM was handled. Just because you SOMETIMES use the Word RAM to send non-video data to the Genesis doesn't mean it's suddenly no good for video. The frame buffer in the 32X is often used to send data to the 32X from the Genesis when you are running CD 32X games as there is no rom cart.

What about the added CPU in the CD, tomaitheous was commenting (toward the begining of this thread, and I think in a couple other discussions as well) that it wasn't really necessary and kind of overkill for the system. OTOH, how could you replace it? Use the Genesis CPU instead? (would that be possible?) And if you did so, wouldn't it make generating an additional genesis graphics layer less practical as well?

Or was the CD's 68k really an asset for the console?

If there was ONLY the Genesis CPU and a VDP on the CD instead of the CPU, then you'd make the 512 KB of Program RAM on the CD more accessible to the Genesis CPU. That would make it use the Word RAM less, which would then be more free for the VDP use. I think most devs would have exchanged the extra CPU for a VDP and better graphics.

[kool kitty89]

The genesis CPU would still be limited to accessing 128 kB banks of RAM at a time through the expansion port, right?

For practical lmitations of the Genesis 68k's processinbg power, there would still be some of the slowdown issues as with some genesis games, right? (I'm not sure how this would effect performance though)
Could including the program RAM seperately, on a cartridge be advantageous? (in the Genesis CPU arrangement) You wouldn't have to deal with bank switching, but then again, you'd need additional hardware on the cart to manage the DRAM. (plus you'd have to take it out to play Genesis games, and if you wanted a memory card/cart you'd need a seperate port onboard the CD or a onboard the ram cartridge)

And again, would using the Genesis CPU still make it practical to use generate a seperate layer of the game with the Genesis VDP? (like with the 32x) Or would the ASIC+Super VDP be capable enough that this really wouldn't be necessary in either case? (though you'd still need a video mixing cable -or at least passthrough- for the Genesis display to maintain a single video output)


And on a somewhat different note, what if they'd gone the the other direction with the ASIC, with the psudo byte mode it seems like they were planning on having a 256 color mode, but later adapted it for the Genesis VDP (or the ASIC is derived from somthing on one of their arcade boards that did use a 256-color mode), so could it have been more optimized toward the Gensis's VDP? For one it seems like having to store 4b/B is rather wasefull and takes up double the memory it would otherwise (and is completely useless in conjunction with the Genesis VDP, though it could possibly be useful with the 32x as you've both mentioned).
So would it have hellped much if the ASIC worked on ture 4-bit chuncks, or is there some other technically reason I'm ignorant of? (the main advantage I'd think, would be 1/2 the memory to move around, using less bandwidth and with fewer problems with Genesis VRAM)

[Chilly Willy]

It's all hypothetical - what we got is nothing like what we NOW would have like to have gotten. So what would the "ideal" add-on have been? Perhaps the 32X with a CD in place of the SEGA CD. Instead of the other 68000 and the ASIC, have the dual SH2 and the SuperVDP. Keep the CD/audio part the same. The memory could have stayed the same as well given that the 512 KB of Program RAM on the CD was twice what they included on the 32X.

[kool kitty89]

Well, that would have been nice, and doing that could have made it practical a Sega's flagship next-gen console as well. (in an integrated form as well as the add-on) Of course with that tech, it would have to be a few years later as well. (the timeline for SH-2's, and the relatively high cost of comperable chips in the 91/92 timeline, I don;t know if the V60 of their early 32-bit arcade systems would have been an option cost-wise either)

But on that note, being "too soon" was part of the problem with the CD, an the real what-if what would have happened if they posponed the original Sega CD desing in favor of something more advanced a couple years later (around '93/94), a hybrid of the Sega CD and 32x design philosophies would definitely have been interesting. It would elliminate the issue of having 2 seperate add-ons confusing things (being expensive to get both, rather cumbersome, and difficult to take advantage of all the hardware) and would have been practical as Sega's full Next-gen system, that like Sega's home consoles before it, would also be backwards compatible with it's predecessor.

It would still probably be limited in comparison to the PSX, but it should still have a good head start, plus the backing of a popular brand with a large userbase. The only contemporary conpetitors would be 3DO and the Jaguar, neither of which are particularly threatening in the long run. (in less you get into speculation on how they could have been handeled better as well )
Tehen again, it brings the question of how Nintendo may have responded to a successful launch of such a system. (whould they have ramped thins up, possibly chosen something something quicker to develop than the SGI chipset, released their own add-on for the SNES, who knows?)


This is all going a lot further than the initial scope of the thread, but if you really want an ideal Sega Genesis add-on, it might be something more than just a hybrid of the two existing desigs as well, particularly considdering the previously discussed weaknesses on each.
From the past discussions I've read on this (and these recent ones), it would seem to be something like this:
---Interface through the Genesis expansion port and include an external mixing cable for the add-on.
Include an SH-2 as the main CPU of the add-on, plus an inexpensive custom DSP coprocessor for geometry calculations and the like. (something like the SVP)
The current added sound chip in the CD is nice, but add a bit more sample RAM for it. (maybe double it to 128 kB)
Use something more than a simple Super VDP/Bitmap display unit (like the 32x has), have something still relatively cheap and simple, but more than waht the 32x has; maybe encorporate something based on the Sega CD ASIC, or expand on the 32x's simple VDP. (Chilly Willy mentioned that adding a bit to the 32x VDP's fill function would have made it useful for blits and simple 3D) Hardware support for texture mapping and gauraud shading would be nice, but that might be pushing it cost-wise.
-Having a similar RAM set-up to the current sega CD could work, but given the later date you might afford sonething more program RAM, like 1 MB (2 MB might not be too expensive, or add provisions for later RAM expansion -other than the Genesis cartridge slot, a direct connection to the CD/add-on's memory bus) Also, perhaps use the full 32-bit data bus of the SH-2 (and same for the video), again cost could be a deciding factor, and the Genesis CPU would still be limited to a 16-bit access for the word RAM.
-Finally, a 2x speed drive would be relatively expensive at the time, so you might make an initial launch with a cheaper 1x speed unit, later release an upgraded 2x speed unit along with the integraded standalone version. (also featuring a 2x drive) Maybe keep the 1x around as a budget model. (or have a budget version of the main console featuring a 1x speed drive as well, though this could start to get cunfusing for the average consumer)


After that there's less technically important things like how to manage game saves and the controller design. On this, I think memory cards are probably the best way to go, EEPROM would be the cheapest to use, but requires additional logic and being significantly slower compared to SRAM+battery, but I think the cost factor would win out. (could the CPU handel the interfacing for this instead of dedicated hardware? Did the PSX do it that way?)
As for the controllers, you could go with standard 6-button, or add Saturn style L+R triggers, it was mentioned before that the Saturn used the same interface logic as the Genesis, with a propritary connector, so anything on the Saturn should still be possible here. Keeping the standard 2x controller ports should be fine, plus there's already multitaps available that could be carried over.

As for marketing, as long as SoJ was relatively reasonable in terms of freedom with SoA (even if they tightened down a bit, it could have been way better than the way things went 1994 onward) things should be fine. There shouldn't be any issuse with Kalinske, and he could contine the great job he'd been doing.
Of course, this is really far more important than any of the issues with hardware, and the thing that really killed Sega historically (infighting/miscomuinication with SoJ), even with everything the same, the Saturn could have been launched much better, the Sega CD and 32x could have been supported significantly longer during the transition to Saturn (probably with more 32XCD support too), and handeled better overall. (phase out Sega CD, Genesis, and 32x together once the Saturn is well established, but not before)

[parallaxscroll]

It would've been amazing if SegaCD had a SuperVDP, then there would be no need for 32X.

Here's what the actual released SegaCD had:
68000 @ `12.5 MHz
ASIC for scaling & rotation


but imagine if instead Sega CD had:
*two 68000s @ 12.5 MHz (for total of three 68000s with Genesis attached)
*SuperVDP allowing more colors (say 8192 on-screen out of 262,144) more sprites (at least 512 if not 1024) and 4 background tile layers etc
*more powerful ASIC for scaling & rotation, as good as the Super-Scaler arcade tech

Overall Sega engineers the SegaCD in 1991/1992 to be on par with their Super-Scaler 'X Board' of 1987 that powered After Burner II, if not the 'Y Board' of 1988 that powered Galaxy Force II. Sega replaces their older arcade boards (including 'Y Board') with the 2D sprite-pushing monster, System32 and 3D polygon MODEL 1 boards in 1991, so that arcade tech is still superior to their home consoles, including SegaCD. At least the SegaCD can handle any Sega arcade game of the 1980s, upto 1990 (G-LOC games).


There is absolutely no 32X. The SegaCD is supported from 1991/1992 to 1996/1997, with the Saturn coming in no sooner than late 1995 in Japan, and 1996 in the U.S.

We get to kill TWO confusing, hurtful formats that did damage to SEGA:
*32X
*32X CD

For the 16-bit era, Sega only has Megadrive|Genesis and MegaCD|SegaCD.

Also, there's no glut of awful FMV games. The SegaCD gets lots of Sega arcade conversions, lots of deep RPGs with spectacualar Sega-80s-arcade quality graphics, and lots of sequels to the best Genesis games, supercharged on SegaCD's immense 2D performance and capacity. Alot of the games that couldn't be done until the mid-late 90s on Saturn with its good 2D performance, are able to be done on SegaCD instead, and sooner.

The Saturn is mostly a 3D console like PlayStation, yet more powerful, and also able to due 2D with even more powerful VDPs with limitless sprite performance. The SegaCD doesn't have limitless 2D performance, but it's as strong as Sega's super-scaler arcade games.

Cost would be high for SegaCD, but overtime it would get less expensive, and with all-in-one Genesis-SegaCD systems, even more affordable by 1994. With it, Sega has a highend 16-bit platform that surpasses NEO-GEO and FM-Towns, dominating the 16-bit era while Nintendo flownders with its own CD-ROM projects that went from 16-bit to 32-bit, from Sony, to Phillips, back to Sony+Phillips, and eventually canceled in favor of Project Reality / Ultra 64, all the while, Sega eats the market. NEC can compete though, with a 16-bit PC Engine 2 (better than the SuperGrafx) combined with Super CD-ROM, although its not as good as SegaCD

[Da_Shocker]

Some of you guys are living in an fantasy land. Rember SoA was pushing FMV games hard as hell back then so all this would've done was is gone from crappy looking FMV games to better looking FMV games. And the machine you guy have bought up sounds a bit underpowered and remember that the main reason Sega dramatically changed the Saturn was to keep up with the PSx.

edit
and parallaxscroll you can't be serious all of that would simply tacked another 1oo dollars on the already exepnsive Sega CD. How on earth can anybody market a 399.99 dollar add on is beyond me. That plus the Genesis takes the unit into Neo-Geo territory.

[kool kitty89]

Shocker, the more I read into the Saturn, th emore that "drastically changed" thing seems like a myth, particularly adding the second SH-2, maybe they beefed up VDP-1 a bit, but even there I'm not so sure... There's also the little used DSP intended for gemoetry calculations, which would largely make the 2nd SH-2 unnecessary to add for 3D (as a lot of 3D work wouldn't have to be done in software as it is on the 32x), had they really wanted to "fix" it, they'd have made the standard dev kit take advantage of the DSP and make DSP-1 work off tirangles instead of quads. (that's a major change though and I'm not sure how much cost and time it would take; really shouldn't hurt 2D performance too much though, using a pair of trips instead of a single quad -and there's still VDP-2 for all the background stuff)

Also, the Sega CD launched at $299 in the US. (albeit more in Japan's earlier launch, and significantly more in Europe as well, but that's how prices tend to go, look at the Saturn's JP launch price, and that sould relatively well with no pack-in and next to no launch titles -but Virtua Fighter was its killer app)


parallaxscroll, I don't think that's really practical at all, cost would have been increased way too much doing that, and a dual 68k layout isn't particularly good (especially if the have to share the same data bus), iirc a lot of the dual 68k arcade borads used one mainly for just booting the system.

If the Sega CD was to be released at the same time it was historically, doing anything more than adding the simple "Super VDP" would be pushing it, and if anything you'd probably want more RAM before anything else. The "super VDP" should be relatively cheap though, but a small increase in production cost tends to lead to significant retail price increases. (inless of course, Sega ate the extra cost, which they probably could have done) In any case, I think the added cost would have been worth it, even if it added another $50 to the final price tag, as the possibilitys are opened up a lot and the console's lifespan could have been a lot longer. (and it would gradually drop in price, of course)


The Sega CD was launched when it was, because (rather like the Saturn), it was designed for the Japanese market, specifically to compete against NEC's new CD add-on (with Sega in a distant 3rd behind Nintendo and NEC). Had they really worked on the Sega CD seriously as a long term product for all markets, they'd ideally have waited at least another year. Add more RAM (something like double the program ram -1 MB instead of 512 k, and more sample RAM for the PCM chip would be nice too), possibly enhance the ASIC, though the existing one (with a real 256 color/byte mode) if pretty capable if it wasn't limited by the Genesis video hardware. Possibly upgrade to a better CPU, maybe a 68EC020 (to keep cost low, probably a lower-end 12.5/16 MHz one), or possible an SH-1 since Sega seemd to be interested in Hitachi's Super H series. (plus Super H seems to have been aimed at low cost consumer applications, so it's a good choic in that respect) The 68k architecture has the advantage of being very familiar/popular though, so probably make things eaiser to program for.
With the 32-bit CPU, you could widen the bus to 32-bit, but this might add significantly to cost, and I don't know if the ASIC would benifit at all from this. (or be easily modified to do so) An added DSP coprocessor for 3D calculations would be really nice (something likt the SVP chip).

Finally, with a 1+ year later release, the cost of a 1x speed CD_ROM drive should have dropped significantly as well, and by the time it was launched ouside of Japan, even moreso.

Then, instead of the CDX, you could have a full blown integrated, backwards compatible next-gen console that's relatively limited compared to the PSX, but has a huge head start and probably enough to forego the Saturn entirely. 3DO and Jaguar were never really a threat, and by the time the PSX is really catching on ~96, and the N64 is out, Sega could have their next system nearing launch. They shouldn't bother with evolutionary development or backwards compatibility at this point as it'd be too cosly and result in overly complex and limited hardware. Go straight for something like the Dreamcast, or if that's too advanced to be developed by '97, they could have done something a bit less advanced, but using a similarly clean design. (maybe based around an SH-3 rather than SH-4, probably regular CS's instead of GD-ROM, maybe a 4x speed drive, but most importantly, a powerful, yet developer freindly architecture)

By that time they really should put effort into a good anti-piracy system, and being earlier would mean it really wouldn't have the issue the DC did with lacking DVD playback capabilities. (playing VCD's out of the box would be nice feature though, at least for the Asian market where the format was popular, good for in-game video too)


Of course, on top of all this, there's the internal problems with SoJ and SoA's relationship and comunication. Though, if this "alternate" Sega CD really took off in Japan, things probably could have been better (less pressure from Nakayama on SoJ to get sales like SoA had, and less subsequent bitterness from Japanese management toward SoA)
So long as the alternate Sega CD was powerful to port well done conversions of popular Japanese arcade titles, it could have had a similar advantage as the Saturn. (particularly with Virtua Fighter)




All highly speculative of course, but even after the Sega CD launched (historically), they still could have had other options, the whole mess with 32x and Saturn and intermingled internal problems really screwed Sega. Instead of pushing SoA to develop the 32x (or even worse, the origianlly planned "Genesis II") or the Saturn, or even Genesis Virtua Racing, they could have expanded on the existing Sega CD design. No more add-ons though, an integrated Sega CD+Genesis (no CDX, as cool as it is, not good from a marketing standpoint), correct the limitations of the Sega CD, more RAM, modified (or at least minimally for a full 256 color mode) ASIC with coresponding "Super VDP," the (SVP like) DSP to help with 3D, and an upgraded CPU, a 68EC020 should be fully compatible with the 68k. (it doesn't even have the problem of the full 020's 32-bit address bus which caused some compatibility problems with select programs) Maybe enhance the audio too, though just adding more audio RAM could significantly help in itsself. (and CD soundtracks would tend to be used as well, so that really suplements things)

[parallaxscroll]

Some of you guys are living in an fantasy land. Rember SoA was pushing FMV games hard as hell back then so all this would've done was is gone from crappy looking FMV games to better looking FMV games. And the machine you guy have bought up sounds a bit underpowered and remember that the main reason Sega dramatically changed the Saturn was to keep up with the PSx.

edit
and parallaxscroll you can't be serious all of that would simply tacked another 1oo dollars on the already exepnsive Sega CD. How on earth can anybody market a 399.99 dollar add on is beyond me. That plus the Genesis takes the unit into Neo-Geo territory.

Actually the SegaCD that i'm fantasizing about is well beyond the Neo-Geo and at least on par with the 32-bit FM Towns, even beyond that as far as scaling & rotation and other sprite-manupulation effects. Yet no more powerful than Sega's high-end 16-Bit arcade boards of the late 80s. It would be expensive to be sure, at least in 91/92, but games would be cheap, at $30~$40. It would actually be less ridiculous than the Saturn with its 8 seperate processing chips in 94/95. We're talking 4 chips for SegaCD:

___________________________
| Genesis 68000
___________________________
|Sega CD 68000 - 68000
|SuperVDP - SuperScaler ASIC
___________________________

The cost of manufacturing a more powerful SegaCD would be far less than the damage Sega did to themselves during the mid 90s with all the different hardware they put out and failed with.



kool kitty89: I don't agree with beefing the SegaCD as far as having limited 3D capabilities or even 32-bit CPU like SH-1. I believe in keeping the SegaCD based on sprite-scaling technology Sega used in their 80s arcade games. I beleive the Saturn should've been based around Lockheed Martin's 3D polygon texture-mapping technology, at least on par with Model 2, if not newer like the Real3D series, although not as advanced as Model 3. If the Saturn "sat" inbetween MODEL 2 and MODEL 3 technically, it could handle ports from both boards. Upgraded Model 2 games, and scaled down Model 3 games. The Dreamcast would then go well beyond Model 3, upto or even a little bit beyond Xbox1, roughly on par with a GeForce 4 or ATI Radeon 9700, easily crushing the PS2 by the same degree the more powerful Saturn would crush the PS1 & N64.

This is all fantasy, none of this happened or will ever happen. It's just FUN to speculate with what ifs.

[kool kitty89]

Actually the SegaCD that i'm fantasizing about is well beyond the Neo-Geo and at least on par with the 32-bit FM Towns, even beyond that as far as scaling & rotation and other sprite-manupulation effects. Yet no more powerful than Sega's high-end 16-Bit arcade boards of the late 80s. It would be expensive to be sure, at least in 91/92, but games would be cheap, at $30~$40. It would actually be less ridiculous than the Saturn with its 8 seperate processing chips in 94/95. We're talking 4 chips for SegaCD:

___________________________
| Genesis 68000
___________________________
|Sega CD 68000 - 68000
|SuperVDP - SuperScaler ASIC
___________________________

The cost of manufacturing a more powerful SegaCD would be far less than the damage Sega did to themselves during the mid 90s with all the different hardware they put out and failed with.

If you're going to compare that to the saturn, then the Saturn's got 4 main chips too (6 if you include the little used DSP).

Now, apples and apples, for 8 (or the somethimes quoted 9 with the 4-bit system/peripheral manager) processors on the saturn, you've got VDP-1, VDP-2, 2x SH-2 CPU's, 1 SH-1 CD-ROM controller, The system control unit (DMA controller plus the aformentioned DSP), a 68EC000 sound CPU, Yamaha FH1 "sega custom sound processor," and the 4-bit Hitachi MCU "manager."

For your enhanced Sega CD, you've got: 2x 68000's, the custom ASIC, Super VDP, Ricoh RF5C164 sound chip, plus (to be fair) all the genesis hardware. (another 68000, YM2612, PSG, VDP, and Z-80)

As to their failure, it had as much to do with lack of cooperation than anything else (and increasing bitterness of SoJ, but that's not until '93), the best add-on they could create would be one that made the Genesis into the next-gen console, along with releasing the new console which was also backwards compatible. Intrim add-ons, or (in the CD's case) one largely aimed at Japan (in terms of design), were not the best idea.

kool kitty89: I don't agree with beefing the SegaCD as far as having limited 3D capabilities or even 32-bit CPU like SH-1. I believe in keeping the SegaCD based on sprite-scaling technology Sega used in their 80s arcade games. I beleive the Saturn should've been based around Lockheed Martin's 3D polygon texture-mapping technology, at least on par with Model 2, if not newer like the Real3D series, although not as advanced as Model 3. If the Saturn "sat" inbetween MODEL 2 and MODEL 3 technically, it could handle ports from both boards. Upgraded Model 2 games, and scaled down Model 3 games. The Dreamcast would then go well beyond Model 3, upto or even a little bit beyond Xbox1, roughly on par with a GeForce 4 or ATI Radeon 9700, easily crushing the PS2 by the same degree the more powerful Saturn would crush the PS1 & N64.

This is all fantasy, none of this happened or will ever happen. It's just FUN to speculate with what ifs.

I think 3D is a major point to go with, and while not the main thing, it should at least have rudimentary support. (to allow decent ports of Model 1 games and stuff better than what Nintendo was doing with Super FX)

As for the ASIC itsself, a big limiting factor was bing tied to the Genesis VDP and VRAM, with the Super VDP and Sega CD's RAM, it wouldn't have the same bottlenecks, I'm not sure of it's actual capable limitations though -I think it would have been pretty darn capable for 2-D stuff though, especially in conjunction with overlayed Genesis Graphics. No need for a "superScaler" chip...

Anyway, you might not even need the additional DSP and/or faster CPU for 3D, the ASIC already has some polygon rendering capabilities, again limited by the Genny's VDP, and very few games took advantage of this. (I think Stellar Fire might be an example)
This is one of the things Chilly Willy's planning on checking out when he's working on the Sega CD.

[Da_Shocker]

Sega CD had shitty support
32X had shitty support
Sega Saturn had shitty support


It's amazing that the PCECD shitted on the SCD even though it was inferior hardware but they allowed ram upgrades and more on screen colors.

[kool kitty89]

The PC Engine was already more popular than the Mega Drive, the CD unit just widened that and was so popular that it supereceded the card format.

I'm not sure exactly how popular the Sega CD was in Japan, but it's pretty clear it was more popular in the West, and much more popular than the Turbo CD in those markets (Was the TG-16 even released anywhere else in the West than North America?) Of course a lot of this was due to NEC's problematic marketing practices in the US. (they very well might have done better with these practices in European countries, especially as Nintendo was weaker over there)

Anyway, the 32x had most of its developer support from Sega itsself or outside of Japan (the early release of the Saturn really killed it though). Likewise, while the CD may have seen significant support from Japan, it was Western developers like CORE that actually pushed the hardware to do some impressive stuff. (and agian, it was more popular in these regions, not surprizing given the Strength of the Genesis/MD) Hell, some of the better Japanese developed games, like Snatcher, weren't even released on the Mega CD in Japan.

The Saturn is the opposite case, doing relatively well in Japan, far more competitive than previously, especially against Nintendo. (granted, both still beaten by Sony by a good margin in the end)
It did get some good Support in Japan too, the PSX was obviously attractive to developers due to the excellent tools and, later, massive popularity. (plus CD's over Nintendo's expensive and limiting carts)


This was a big part of the problem though, Sega of Japan focused more and more on their own region rather than making sure to maintain or even improve their strong American and European markets. (instead becoming bitter over their success)
Sure, try and expand to the Japanese market more, but by no means make it a priorety over your main successful markets. (even the Sega CD feeds into this, but that's in a rather different context, it launched in Japan when the Genesis was just starting to take off in the US and the only other option would be not to release it outside of japan at all, like with so many other accessories; but I don't think this would have been a good idea)


Having the Sega CD already out on the market makes things a bit trickier for Sega in terms of a successor to the genny. If there was just the stok genesis to worry about, building a new system with backwards compatibility in mind would be rather simple (particularly if you can take advantage of the old hadware, or used compatible but expanded versions of it like the Genesis did for the SMS), especially with Sega getting pretty much all the major components on the Genesis into a single ASIC chip (68k, VDP, PSG, YM2612, Z80) by their final model Genesis 2 (VA-4), so it would take up very little board space.

The other option is completely new hardware w/out backwards compatibility, the Saturn had a number of technical shortcomings though that put it at a disadvantage much of the time. (exaserbated by the poor management of the Saturn and relationship between SoA and SoJ after 1993)
The problem with this is you've already released the Sega CD a few years earlier with fiarly significant sales (enough for approximately 1 in 5 Genesis owners to have one), but not significant enough to use the CD as a stopgap and go for a more long term development of an advanced system to be rleased significantly later. (as would have probably happened had they taken up the SGI chipset that eventually became the N64, or a "dreamcast lite" built around an SH-3)

Had the Sega CD been a little more powerful and come a bit later, had the independent, 32x-like "super VDP" it could have provided this though, great 2D and basic 3D capabilities, enough to handel ports from the System 1 (especially Virtua Fighter, in terms of the Japanese market), and being able to handel a port of another very significant killer app, Doom!

[tomaitheous]

It would've been amazing if SegaCD had a SuperVDP, then there would be no need for 32X.

Here's what the actual released SegaCD had:
68000 @ `12.5 MHz
ASIC for scaling & rotation


but imagine if instead Sega CD had:
*two 68000s @ 12.5 MHz (for total of three 68000s with Genesis attached)
*SuperVDP allowing more colors (say 8192 on-screen out of 262,144) more sprites (at least 512 if not 1024) and 4 background tile layers etc
*more powerful ASIC for scaling & rotation, as good as the Super-Scaler arcade tech

Overall Sega engineers the SegaCD in 1991/1992 to be on par with their Super-Scaler 'X Board' of 1987 that powered After Burner II, if not the 'Y Board' of 1988 that powered Galaxy Force II. Sega replaces their older arcade boards (including 'Y Board') with the 2D sprite-pushing monster, System32 and 3D polygon MODEL 1 boards in 1991, so that arcade tech is still superior to their home consoles, including SegaCD. At least the SegaCD can handle any Sega arcade game of the 1980s, upto 1990 (G-LOC games).

Here's the main problem I have with this; where does the Genesis fit into that design? If you're going to give it that much hardware, it doesn't even need the Genesis hardware. Matter of fact, you don't even need the custom ASIC. Might as well condense an X or Y board itself into integrated chips along with the CD interface unit and call it done. What you're proposing is a whole new/separate system rather than an add-on. I also imagine a price tag of like 600-700USD minimum for that thing.

I think realistically you need to meet certain requirements at a target budget that the average gamer can afford. What was lacking on the Genesis compared to the SNES (excluding NEC outside of Japan)? Colors onscreen, scaling/rotation, transparency, sound. I know a lot of people here argue the quality and style of the YM2612 over the SPC700 unit, but at the time of the SNES release - generally speaking the Genesis sound was considered inferior. I think the SNES showed that you didn't even need insane amount of sprites or 5 independent BG layers, or whatever. Hell, the most popular games on the SNES where pretty much eye candy color fidelity and sound. A system X or Y equivalent board would be waaaaay overkill. If the games associated with those arcade board were soooo popular, then why wasn't the home market flooded with them?

The SegaCD already had the ASIC and while not X/Y board prowess, it did provided effects not capable on the SNES. The PCM unit isn't exactly on par with the SNES, but it's close enough and easily paired with the FM/PSG units. It has a dedicated processor to handle sampled-based synthesis using the PCM unit. And then there's the CD audio factor. The only thing missing from the SegaCD was a nice bitmap Super VDP that overlaid with the Genesis video (maybe even a color add/sub/mul mode between the two), and a CLUT system for the incoming pixels of the Genesis RGB signal. No extra processors, no faster ASIC, no super sprite scaling monster. The SegaCD had everything else to be on par and ahead of the SNES except color depth.

If Sega released that as an addon and also released an all-in-one SegaCD "Duo" at the same time in 1992, it would have showed that Sega was truelly focused on CD gaming as its future. The price; $199 for the addon and $299 for the all-in-one.