I find it hard to believe that the V9978 wouldn't have backwards-compatibility with V9958 on the same dye, at least not without some good evidence.
That's why I think the V9990 could be hiding a disabled V9958 circuit in the dye. Since the V9990 was made to cover some of Yamaha's losses for developing it, and because removing the V9958 features would just make it more expensive, it might had been cheaper to keep the V9958 in there and just make some smaller changes that renders the V9958 features unusable/inaccessible instead of removing them fully for licensing reasons.
That's why I think the V9990 could be hiding a disabled V9958 circuit in the dye.
Nowadays it could make some sense. But at the time it is almost unheard of leaving that much dead silicon behind. I can't imagine a good reason to de-feature it once it was implemented. It would make more sense to release with the compatibility.
It is conceivable that if the projects was not too advanced they could remove things. If the project was more advanced and the feature already implemented it is more likely they would go with it. Particularly after losing their "lead customer", they would either cancel it or productize it as fast as possible.
And as they release it as a video card for PCs, makes me think they still saw a market for it. What in the end was great for us...
As long as the chip isn't physically designed, it's probably not difficult to remove the v9958 part.
Then, we do not know if this part was present. Maybe Yamaha planned a chip that works with the v9958 in parallel.
I think the opposite. merging v99x8 to v9990 would have been incredibly complex a leaded to enourmous complexity issues.
Yamaha knew that from beginninng. And i think they considered different chips because of irreconcilable different not only in internals but even on external pinout. If you look to v9990 pinout and v99x8 one it is clear that they have too much different architectures (BUS data size, dual ported ram, ect) to reconcile them into a single chip. Not to mention the issues that could arise when interfacing this chip with external ones (like cpu, ram etc)
I do not think there are hidden v99x8 parts in the v9990, even in the first prototypes, they did not even considered it
Maybe Yamaha planned a chip that works with the v9958 in parallel.
To me this appear the most "sane" and logical solution.....
Anyone know when (date) the v9990 was officially available?
I think the opposite. merging v99x8 to v9990 would have been incredibly complex a leaded to enourmous complexity issues.
Nobody says it's easy to merge v99x8 to v9990.
If you look to v9990 pinout and v99x8 one it is clear that they have too much different architectures (BUS data size, dual ported ram, ect)
We know it.
I think the opposite. merging v99x8 to v9990 would have been incredibly complex a leaded to enourmous complexity issues.
Nobody says it's easy to merge v99x8 to v9990.
If you look to v9990 pinout and v99x8 one it is clear that they have too much different architectures (BUS data size, dual ported ram, ect)
We know it.
Then it should be clear that the most logical approach was to separate in two different chips those incompatible things instead of wasting time / resources / cost trying to fit bananas+oranges togheter leading to some horrible technical tradeoff i can only try to immagine ;-)
If you suddenly saw an original MSX3 for sale on Amazon without knowing everything we were talking about, what would you do? You would probably buy it hoping to relive the old feelings you had with your first MSX. When I received my first MSX, I knew nothing about its history or how it was designed. But I have loved it all my life. Now each of us will have to take stock and decide whether or not to try this new experience.
If you suddenly saw an original MSX3 for sale on Amazon without knowing everything we were talking about, what would you do? You would probably buy it hoping to relive the old feelings you had with your first MSX. When I received my first MSX, I knew nothing about its history or how it was designed. But I have loved it all my life. Now each of us will have to take stock and decide whether or not to try this new experience.
Agree <3
gdx wrote:
As long as the chip isn't physically designed, it's probably not difficult to remove the v9958 part.
Then, we do not know if this part was present. Maybe Yamaha planned a chip that works with the v9958 in parallel.
I do not think there would be a v9958 "part" as a very separated entity. The modes both chips provide are already very similar and they would have taken advantage of it in the design. It is more likely that hey would implement the different modes as "parameters" applied to a state machine that would be capable of doing both things. And in the end, removing that would make less sense.
It is very plausible that they would consider a system with both chips also. We can speculate a lot about that.
I do not believe the physical desig was not started. It is possible. But it does not fit very well with the information that Yamaha was delayed. If physical design was not started by the time MSX dropped the chip, there is little reason to continue and finish it. It was very early in the flow and it could be dropped. It doesn't sound like a delay, sounds more like they didn't even start it.
On the other side, bugs on the chip could cause it to be delayed to the point of being dropped. And after you sunk all the investment you may as well release it to see if it gets traction.