Saturn Custom Sound Processor

From Sega Retro

The Saturn Custom Sound Processor (SCSP) is manufactured by Yamaha and consists of several components.

The SCSP is a multi-function game sound generator LSI that consists of a PCM sound generator and DAC (Digital Audio Converter). The SCSP creates processes sound mixes. It contains 32 slot sound generator and sound effect DSP, 16 channel digital mixer and timer, and an interrupt controller. The Saturn's audio RAM is connected directly to the SCSP, and is used to store the sound programs (i.e. Cybersound) or raw waveform samples. The SCSP can support up to 32 channels for PCM playback, or 8 channels for FM synthesis modulation. Maximum sample rate for PCM samples is 44.1Khz (CD Quality). The SCSP is MIDI-compliant, and can be hooked up to external equipment (such as keyboards).

The 128 step Digital Signal Processor is capable of generating special effects such as reverberation and different room acoustics.

The entire SCSP is controlled by a single Motorola 68EC000 16-bit CPU running at 11.3Mhz. The MC68EC000 is essentially the same as (and compatible with) the M68000 used in the Mega Drive and several other consoles, but without the 8-bit MC6800 interface. The SCSP can be directly accessed by the MC68EC000 and both SH2s.

The SCSP is a fantastic system limited only by the small amount of RAM made available to it, and a lack of hardware sample compression.

  • 22.6 MHz Yamaha FH1 digital signal processor
  • Any of 32 slots can be linked together for multiple operators per FM sound channel
  • Usually four operators used per slot for 8 FM channels total
  • 44.1 kHz sampling rate