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.
sadly, the Game.com ended up being a failure as well, mostly due to poor quality games. the Game.com only lasted 3 years before being discontinued.
however, for its time, it was a pretty competitively priced system. the Game Boy Color was to be released in a year for $79.95, while the Game.com was released for $69.99; 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 not implemented in Furnace.
10xx: set waveform.xxis a value between 0 and 255 that sets the waveform of the channel you place it on.
this chip uses the SM8521 instrument editor.
the following options are available in the Chip Manager window:
- Clock rate: sets the rate at which the chip will run.