POKEY

a sound and input chip developed by Atari for their 8-bit computers (Atari 400, 800, XL/XE and so on). 4 channels of signature Atari sounds.

effects

• 10xx: set waveform.
• 0: harsh noise (poly5+17)
• 1: square buzz (poly5)
• 2: weird noise (poly4+5)
• 3: square buzz (poly5)
• 4: soft noise (poly17)
• 5: square
• 6: bass (poly4)
• 7: buzz (poly4)
• 11xx: set AUDCTL. xx is a bitmask.
• bit 7: 9-bit poly mode. shortens noise.
• bit 6: high channel 1 clock (~1.79MHz on NTSC).
  • overrides 15KHz mode.
• bit 5: high channel 3 clock (~1.79MHz on NTSC).
  • overrides 15KHz mode.
• bit 4: join channels 1 and 2 for a wide period range.
  • use with conjunction with bit 6.
  • channel 2 becomes inaccessible when this is on.
• bit 3: join channels 3 and 4 for a wide period range.
  • use with conjunction with bit 5.
  • channel 4 becomes inaccessible when this is on.
• bit 2: high-pass filter (channels 1 and 3).
  • filtered output on channel 1 (I suggest you to set channel 3 volume to 0).
  • use for PWM effects (not automatic!).
• bit 1: high-pass filter (channels 2 and 4).
  • filtered output on channel 2 (I suggest you to set channel 4 volume to 0).
  • use for PWM effects (not automatic!).
• bit 0: 15KHz mode.
• 12xx: toggle two-tone mode.
• when enabled, channel 2 modulates channel 1. I don't know how, but it does.
• only on ASAP core.

info

this chip uses the POKEY instrument editor.