Mensaje
por PiyoTaro » 19 Ene 2019, 12:57
There are several kinds of Konami "SCC" sound chips, but those adopted for game cartridges of MSX have 5 channels "Reproduce with 1 cycle of waveforms with 8 bits 32 samples".
Also, with NEC's PC engine ("TurboGraphics" in the United States), you can use up to 6 channels of "1 cycle 5 bit 32 samples" sound.
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About SCC, I have posted to the "ZXSpectrum Next Official Forum".
About the implementation of FM Sound of ZXNext, the circuit size of "SID" was too large to be drowned. Also, it was an answer that "OPN software core" can not be adopted.
However, it seems that the development of the core is still continuing from the debate of the Official Facebook, so I would like to propose not only the Sprite but also the extension of the music function.
Is there a small synthesizer core compared to OPLL (or Konami VRC7) or SID?
When I heard a lot of past C64 soundtracks, even if there are no filters or ring modulator, if you can select some preset waveforms close to the basic waveform (sawtooth wave, triangular wave etc.), a sound similar to SID I thought that I could make it.
Approach to further simplify the function of SID. For example, you can create something like a synthesizer by choosing the waveform shape for each half cycle of the output waveform, or designating the duty ratio of the output waveform.
The merit of adopting the synthesizer chip is that it is possible to "change the timbre over time", but it can also be reproduced by playing one part with multiple sound sources.
Since "AY-3-891x" has the upper bit of the register fixed to "0", I think that the function can be extended. I posted such a thing on the official forum of ZXNext.
"Turbo sound", AY is adopted. Would it be possible to adopt the waveform memory sound?
Add 6ch * 32 samples = 192 waveform memories to the SAA 1099 like register map. I think that it may be possible to sacrifice "noise generator" and "hardware envelope function".
Also, if Konami "SCC" is reproduced by FPGA, how big can it be realized by the circuit size compared to OPLL and SID?