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Here's food for thought! Add a bit somewhere to change the SCC's volume register implementation so that it becomes logarithmic instead of linear, making it far more suitable to team up with a PSG..

Wolf, it is just a matter of doing a small conversion table in you SW.
Log values - > Linear Values
We did it, and we convert PSG log volumes to SCC linear volumes on fly.
This allows PT3 music to be played trough SCC and mixed to the PSG music.

No cost, and no reason to prevent the SCC to play PCM

ARTRAG, instead of 'abusing' an SCC to do what it's not designed for to do, it'd be better if I were to add a buffered PCM wave engine AKA Moonsound. After all, if people were to get a VDPX for the expanded VDP capabilities, they would have access to any additional features I would build into VDPX.

(Dang I keep typing SSC... been playing World of Warcraft too much )

Well, I do not know the cost of opening a new I/O window in the memory,
I was only thinking that if you implement SCC, you have already at least 128bytes of memory mapped I/O.
More memory I/O we do, less ram/rom space the z80 will have for code and data.

Naturally having a buffer for PCM audio would be excellent.

It wouldn't cost any additional hardware. Well.. perhaps a separate 1MB lowcost/lowspeed SRAM so the megaram/PCM would not consume any bandwith from VRAM which I decided to make 1MB as well. Then VDPX would come with 1MB VRAM and 1MB Expander RAM. Since PCM is low frequency anyways, 44.1KHz at most, bandwidth for PCM and megaram features are easily shared.

As for the 64KB address space, 4000-BFFF would be the megaram/SCC if enabled. Page 0, VRAM can also be mapped in any of the 4 slot pages. Through one memory control register one can specify to access the megaram/SCC or VRAM. In Video routines you'd swap in VRAM and upon completion swap back megaram/SCC. Or you could chose to access VRAM through read/write pointer based OUTs.

This way you can get most out of one single slot

BTW how much memory a Moonsound cart has?

Hey, a multimedia extension for msx? :-)

Do you plan to output the audio channel also on the cartridge pin?

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All good VDPX games when they appear will be in assembly

I think there is also room to 'c' or pascal if mixed with time critical parts in assembly .
the savings that allow the vdpx could be 'wasted' in a less performant language.

However, i see problematic to game a good game in msxbasic, even moving *fast* with 4 sprites is hard in this language.

Yes, there would be audio going into the MSX. Fun thing is that the scc channels could have an extra balance control per channel too. I'd have to add two RCA receptors too for stereo output

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BTW how much memory a Moonsound cart has?

Models sold in the 90's came with 128KB SRAM. Recent models come with more, prolly 1MB or something.

Right on. Anyways, for now I'll keep the focus at the graphics part itself

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Right on. Anyways, for now I'll keep the focus at the graphics part itself

Hi, magicbox... i haven't seen any new post. Hoping you do not got personal problems...

Sorry, but it's a matter of priorities. A family member passed away last week and I have more urgent matters during this time. Don't worry, I'm not dropping the project. It just gets more or less attention depending on how much time I can / want to spend to it.

No problem at all. I've suspected something like you said. My Condolences ...

Well, today I received my CycloneIII dev kit. Don't have the LCD kit yet, it's on its way. I did get some time to finish up the VRAM arbiter, but as it stands now I'll probably be using a different kind of SRAM which allows an even higher bandwith, though its easier to interface with.

@MagicBox: hope you have resolved your issues: well back.

And a question: what's a LCD kit?