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The YM2612, a.k.a. OPN2, is a sound chip developed by Yamaha. It is a member of Yamaha's OPN family of FM synthesis chips, and was developed as a stripped-down version of the YM2608.

The YM2612 is a six-channel FM synthesizer used in several game and computer systems, most notably in Sega's Mega Drive/Genesis video game console as well as Fujitsu's FM Towns computer series. It was also available in CMOS form as the YM3438, a.k.a. OPN2C.

  • Six concurrent FM synthesis channels (voices)
  • Four operators per channel
  • Two interval timers
  • A sine-wave low frequency oscillator (LFO)
  • Integrated stereo output digital-to-analog converter (DAC) (most other contemporary Yamaha FM chips require a separate DAC chip)
  • Per-channel programmable stereo sound (left, right, or both left and right resulting in centre)
  • For channel three, operator frequencies can be set independently, making dissonant harmonics possible (Normally, they would have a simple relation like e.g. 2× or 3× relative to a common base frequency). This is shared across multiple chips in the OPN series.
  • For channel six, basic playback of sampled audio can be enabled via a register on the chip, disabling FM output for that channel but allows for a single channel for samples in 8-bit pulse-code modulation (PCM) format, with sampling rates being controlled by software (This channel is often referred to as the "DAC" channel, which primarily refers to the chip's built-in 9-bit DAC output).

Notes

See also

  • VGM – an audio file format for multiple video game platforms, including the Sega Mega Drive/Genesis
  • Yamaha YM2203
  • Yamaha YM2608
  • Yamaha YM2610

References

  • Nuked-OPN2 YM3438/YM2612 emulator