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Refactoring + add DAC channel

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nicco1690 2023-02-11 22:09:59 -05:00 committed by GitHub
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11
papers/doc/7-systems/sm8521.md
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@ -6,7 +6,16 @@ Ultimately, most of the games for the Game.com ended up being failiures in the e
However, for its time, it was a pretty competitively priced system. The Gameboy Color was to be released in a year for $79.95, while the Game.com was released for $69.99, and its later model, the Pocket Pro, was released in mid-1999 for $29.99 due to the Game.com's apparent significant decrease in value.
The sound-related features and quirks of the SM8521 are as follows: 2 4-bit wavetable channels, a noise channel, 5-bit volume, and a low bit-depth output which means it distorts a lot. It also phase resets when you switch waves.
In fact, most games never used the wavetable/noise mode of the chip. Sonic Jam, for example, uses a sine wave with a software-controlled volume envelope on the DAC channel (see below for more information on the DAC channel).
The sound-related features and quirks of the SM8521 are as follows:
- 2 4-bit wavetable channels
- a noise channel (which can go up to a very high pitch, creating an almost periodic noise sound)
- 5-bit volume
- A low bit-depth output (which means it distorts a lot).
- It phase resets when you switch waves
- 12-bit pitch with a wide frequency range
- A software-controlled D/A register that (potentially) requires all other registers to be stopped to play. Due to this, it is currently, it is not implemented in Furnace as of version 0.6pre4.
## effect commands