PSG
This page was last modified 21:47, 27 April 2020 by Mars2000you. Based on work by Grauw and Gdx and others.

Description

The standard sound chip in the MSX is called the PSG (Programmable Sound Generator). It can play either a tone or noise on each of its three voices. It also controls the Joystick ports and a few other things.

Like other parts of the MSX specification, the PSG chip was an off-the-shelf part. In this case the General Instrument AY-3-8910, which can also be found in many other systems of the era. This chip, or one of its clones, can be found in many MSX1 systems. In newer MSX systems, the PSG is often integrated in a chip called the MSX-Engine (or MSX-System).

List of fully compatible clones:

  • File KC89C72 (used in an Arabic MSX)
  • JFC 95101 (not used in MSXs)
  • Microchip Technology AY-3-8910A (not really a clone because Microchip Technology is the old semiconductor division of General Instrument)
  • OKI M5255 (rare, ? not used in MSXs)
  • OY-2-8910AC (used in an Arabic MSX)
  • Toshiba T7766A (official clone used in MSXs -sometimes as a separated chip or often embedded on MSX Engine)
  • WB5300 (rare, not used in MSXs)
  • Winbond WF19054 (rarely used in MSXs)
  • Yamaha YM2149 (official clone often used in MSXs -either as a separated chip or embedded on MSX Engine)

Note: The Yamaha YM2149 is called SSG (Software-controlled Sound Generator).

Software that uses the PSG for BGM and/or SFX.

Stereo

The General Instrument AY-3-8910 outputs the three channels separately, and so do the Yamaha YM2149 and the PSGs integrated in the Toshiba T7937 and Toshiba T9769 MSX-ENGINEs. The Yamaha S1985 MSX-SYSTEM mixes the channels into a left and right channel (A: Center, B: Left, C: Right). The Yamaha S3527 MSX-SYSTEMII integrated PSG is down-mixed to a single mono channel.

Most MSX computers output mono, however some machines pan the channels to center, left and right. Depending on the machine the left and right channel are swapped. Below is a table of MSX models with stereo output and the panning of the respective channels.

Model Channel A Channel B Channel C Notes
Daewoo CPC-400  ?  ?  ? Stereo / mono switch on the back.
Daewoo CPC-400S  ?  ?  ? Stereo / mono switch on the back.
National FS-5000  ?  ?  ? Stereo / mono switch on the back.
National FS-5500F1  ?  ?  ? To be confirmed.
National FS-5500F2  ?  ?  ? To be confirmed.
Pioneer PX-7 Center Left Right
Pioneer PX-7(HB) Center Left Right
Pioneer PX-V7 Center Left Right
Sony HB-F900  ?  ?  ? To be confirmed.
Toshiba HX-20 * Center Right Left Stereo / mono switch on the back.
Toshiba HX-21 Center Right Left Stereo / mono switch on the back.
Toshiba HX-22 * Center Right Left Stereo / mono switch on the back.
Toshiba HX-23 Center Right Left Stereo / mono switch on the back.
Toshiba HX-23F Center Right Left Stereo / mono switch on the back.
Toshiba HX-32 Center Right Left Stereo / mono switch on the back.
Toshiba HX-33 Center Right Left Stereo / mono switch on the back.
Toshiba HX-34 Center Right Left Stereo / mono switch on the back.
  • = only theJapanese model


External links