1.7 KiB
Sharp SM8521
The SM8521 is the CPU and sound chip of the Game.com, a handheld console released in 1997 as a competitor to the infamous Nintendo Virtual Boy.
Ultimately, most of the games for the Game.com ended up being failures in the eyes of reviewers, thus giving the Game.com a pretty bad reputation. This was one of the reasons that the Game.com only ended up selling at least 300,000 units. For these reasons and more, the Game.com ended up being discontinued in 2000.
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.
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
10xxSet waveformxxis a value between 0 and 255, that sets the waveform of the channel you place it on.