YM2610

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Cd2 ym2610.jpg
Package SDIP64
Manufacturer Logo yamaha.jpg
First use 1990 ?
Approx. gates ?
Used on All systems

The YM2610 is a sound synthesis and playback chip made by Yamaha, found in all versions of the NeoGeo hardware. It was later merged with other chips in Chipicon.png NEO-YSA and Chipicon.png NEO-YSA2, which are used on some versions of the NeoGeo CD, the CDZ, the Pcb.pngMV1C and on ROM-Only boards.

The YM2610 requires a Chipicon.png YM3016 external DAC (Digital to Analog Converter) chip for the FM and ADPCM sounds. The only direct analog output is for the SSG sounds. Both analog outputs are then mixed together before amplification.

The original YM2610 chip gets quite warm during normal operation.

Parts

Sound can come from 3 different generators, each having their own channels:

  • SSG (Software Sound Generator): 3 channels
  • FM (Frequency Modulation): 4 channels
  • ADPCM (Sample playback): 7 channels

Providing 14 channels in total.

Programming

See Z80/YM2610 interface and YM2610 registers.

Pinout

width=400px
  • Sig.pngSDD: Chipicon.png Z80 data bus
  • Sig.pngRAD: ADPCM-A multiplexed address/data
  • Sig.pngRMPX: ADPCM-A address/data select
  • Sig.pngROE: APDCM-A data output enable
  • Sig.pngRA: ADPCM-A address
  • Sig.pngANA: SSG analog output
  • Sig.pngSH1: Chipicon.png YM3016 latch 1
  • Sig.pngSH2: YM3016 latch 2
  • Sig.pngOP0: YM3016 serial data
  • Sig.pngIC: Reset
  • Sig.pngPA: ADPCM-B address
  • Sig.pngPOE: ADPCM-B data output enable
  • Sig.pngPMPX: ADPCM-B address/data select
  • Sig.pngPAD: ADPCM-B multiplexed address/data
  • Sig.pngIRQ: Interrupt request output
  • Sig.pngCS: Chip select
  • Sig.pngWR: Write
  • Sig.pngRD: Read
  • Sig.pngSDA: Z80 address bus
  • Sig.pngPHI M: Clock input
  • Sig.pngPHI S: YM3016 clock output


Multiplexed PCM bus

Access to the V ROMs are made via partly multiplexed buses. See YM2610 bus timing for more details about the access sequences.

The Sig.pngSDRMPX and Sig.pngSDPMPX signals are used to drive latches or the Chipicon.png PCM chip in cartridges to demultiplex address and data. When Sig.pngSDROE or Sig.pngSDPOE goes low, SDRAD* and SDPAD* are tristated so that the V ROMs can output data.

  • SDRA* for ADPCM-A
SDRMPX SDRAD* SDRA*
0 1 2 3 4 5 6 7 8 9 20 21 22 23
Low to high 0 1 2 3 4 5 6 7 8 9 ? ? ? ?
High to low 10 11 12 13 14 15 16 17 18 19 20 21 22 23
  • SDPA* for ADPCM-B
SDPMPX SDPAD* SDPA*
0 1 2 3 4 5 6 7 8 9 10 11
Low to high 0 1 2 3 4 5 6 7 8 9 10 11
High to low 12 13 14 15 16 17 18 19 20 21 22 23

24 address bits allow for 16MiB max V ROMs (without bankswitching).

Trivia

  • A lot of games have several recordings of the same instrument playing different notes, rather than having only one sample and change the ADPCM-B playback frequency to vary its pitch. (Trumpet in Viewpoint, electric guitar in Super Sidekicks). Why ?
  • Nazca's sound drivers are able to use the SSG channels for music playback. (Maybe all can ?)

Datasheet

Japanese datasheet: [ajworld.net]

Incomplete/translated datasheet: [YM2610.pdf]