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.

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.

effects

• 10xx: set waveform.
• xx is a value between 0 and 255 that sets the waveform of the channel you place it on.

info

this chip uses the SM8521 instrument editor.

chip config

the following options are available in the Chip Manager window:

• Clock rate: sets the rate at which the chip will run.