AY-3-8910

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The AY-3-8910 sound chip from GI production
The AY-3-8910 sound chip from Microchip production

The AY-3-8910 was a sound and multi-I / O chip that was widely used in earlier home computers and gaming machines and was developed by General Instrument in the early 1980s. Slightly modified, it was licensed to Yamaha as the YM2149 and manufactured by Microchip , the outsourced microelectronics division of GI, from 1987 onwards. The chip was found in most of the early arcade games , but also in some home computers , including the Schneider / Amstrad CPC , ZX Spectrum 128K and Atari ST .

technology

The main part of the chip was intended for sound and noise generation. The AY-3-8910 had three independent voices, the frequency of which was adjustable in 1024 steps. The volume of each voice was adjustable in 16 steps, in addition there was a common envelope generator for all three voices. For each voice it was possible to set whether the envelope should be used. There was also a random generator in the chip, which could be queried by the processor or added to each voice as a source of noise.

A special feature was that each voice had its own output pin. Usually they were simply interconnected outside of the chip, but in principle three-channel sound or stereo plus a common voice for right and left was also possible.

The two 8-bit wide I / O ports could each be switched as a group to input or output. Since the port pins were switched as an open collector , it was also possible to mix inputs and outputs on one port. For example, the connection of joysticks , fire and control buttons and a keyboard matrix was conceivable .

The chip was designed for connection to a special bus used by GI's in-house CPUs . However, since in practice it was usually not interconnected with these rarely used processors, but z. B. with the Zilog Z80 or the MOS Technology 6502 and their variants, the bus had to be simulated, e.g. B. using glue logic or an interface module such as the MOS Technology VIA and additional software support.

The module was manufactured in various technologies / packages . The standard version was a DIL -40 housing. Later it was also available in smaller cases, but it is no longer manufactured.

predecessor

  • AY-1-0212 (top octave synthesizer chip)
  • AY-3-214

variants

  • AY-3-8910 - original version with 40 pins, two I / O ports 8 bits each
  • YM2149 - Pin and Register Compatible, from Yamaha
  • AY-3-8912 - smaller version with 28 pins, only one I / O port with 8 bits
  • AY-3-8913 - most compact version with 24 pins, completely without an I / O port
  • AY-3-8914 - variant of the AY-3-8910 with different register assignment

successor

  • YM3439 - CMOS version of the YM2149
  • YM2151
  • YM2203

Home computers / consoles (selection)

Arcade games (selection)

AY-3-8910 Crazy Kong, Frogger , Moon Patrol , Kung-Fu Master ( Irem M-62 Hardware), Tron , Burgertime

Web links