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Tech Specs of the K053260 Sound Chip?
http://forums.nesdev.com/viewtopic.php?f=23&t=11406
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Author:  Jedi QuestMaster [ Tue Jul 08, 2014 2:58 pm ]
Post subject:  Tech Specs of the K053260 Sound Chip?

I can't seem to find any information about the K053260 chip anywhere.

From what I know, it's a sample-based sound chip used by Konami that goes along the YM2151 sound chip in Asterix, Sunset Riders, Turtles in Time, and other arcade games from the same time period.

I'd like to know how many channels this contains and what quality samples it supports.

Anyone know where I can find this out?

Author:  lidnariq [ Tue Jul 08, 2014 3:49 pm ]
Post subject:  Re: Tech Specs of the K053260 Sound Chip?

MAME's source has an implementation. Looks like four 8-bit DACs with some kind of compressed format feeding it.

Author:  Drag [ Wed Jul 09, 2014 2:54 pm ]
Post subject:  Re: Tech Specs of the K053260 Sound Chip?

A lot of arcade machines use an OKI chip for digital samples, which uses a 4-bit (I think) adpcm format; same as the .vox format. Without looking at the implementation, this could be the compression scheme.

Author:  Jedi QuestMaster [ Sat Jul 12, 2014 9:39 am ]
Post subject:  Re: Tech Specs of the K053260 Sound Chip?

Thanks.

Those MAME pages came up, but I didn't know what I was looking at.

Author:  lidnariq [ Sat Jul 12, 2014 10:38 am ]
Post subject:  Re: Tech Specs of the K053260 Sound Chip?

Jedi QuestMaster wrote:
Those MAME pages came up, but I didn't know what I was looking at.


http://mamedev.org/source/src/emu/sound/k053260.c.html wrote:
Code:
   39      k053260_channel             channels[4];
→ 4 channels
Quote:
Code:
  169                              if ( ppcm_data[i] > 127 )
  170                                  ppcm_data[i] = 127;
  171                              else
  172                                  if ( ppcm_data[i] < -128 )
  173                                      ppcm_data[i] = -128;
→ 8 bit DAC
Quote:
Code:
  361              case 7: /* volume is 7 bits. Convert to 8 bits now. */
[...]
  378          case 0x2c: /* pan */
  379              ic->channels[0].pan = v & 7;
  380              ic->channels[1].pan = ( v >> 3 ) & 7;
→ 7 bit volume control and 3 bits panning per channel

Various things I find odd:
1-the packed PCM (a more advanced DPCM than the NES uses, closer to conventional ADPCM) is signed but the raw PCM is unsigned. The IC probably converts the unsigned data to signed before volume and panning.
2-the panning code doesn't provide the ability to pan things hard left. It seems more likely to me that the IC doesn't provide the ability to pan things dead center

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