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PSG
,/* Chip Variants */
== Chip Variants ==
The PSG chip family is composed of 3 variants: the AY-3-8910 with two 8-bit I/O ports, the AY-3-8912 with one 8-bit I/O port and the AY-3-8913 with no I/O port. In addition to the CPC, these chips were also used in the [[KC Compact]], [[ZX Spectrum]], [[MSX]], [[Oric]], [[Vectrex]], [[Intellivision]] and in the Mockingboard expansion for the [[Apple II]].
The PSG chip competed with the DCSG (Digital Complex Sound Generator) chip family (SN76489, SN94624, TMS9919) by Texas Instruments. The DCSG has similar sounding features except that it does not have any envelope control and that its noise generator has its own dedicated channel.
Toshiba T7766A, Winbond WF19054, JFC 95101 and File KC89C72 are clones of the PSG. [https://wiki.agiri.ninja/sound_chip_clones:index Source]
Yamaha produced the SSG (Software-controlled Sound Generator) chip family (YM2149F, YM3439, YMZ294, YMZ284, YMZ285) which is a quasi-clone of the PSG. The main difference is that the envelope counter on the PSG has 16 steps. On the SSG it has twice the steps, happening twice as fast. This chip equips the [[Atari ST]], [[Aleste 520EX]] and some [[MSX]] computers. [https://www.cpcwiki.eu/imgs/a/ae/ALESTE_520EX_PCB_Top.jpg Source1] [https://www.msx.org/wiki/Yamaha_YM2149 Source2some MSX computers].
The SSG has also been integrated as a component inside some of the arcade soundchips of the Yamaha OPN family. That's why you can find it in the [[Neo-Geo]] as a component inside the YM2610 soundchip.
