Hyper Voice

Hyper Voice is a headphone-only sample output channel introduced with the WonderSwan Color. It allows converting 8-bit signed and unsigned, mono and stereo samples into 16-bit signed PCM sent directly to the headphone output, after mixing with the traditional four channels.

I/O Ports

Hyper Voice Right Output ($66, $67 write)

15  bit  8  7  bit  0
 ---- ----  ---- ----
 ssss ssss  ssss ssss
 |||| ||||  |||| ||||
 ++++-++++--++++-++++- Signed 16-bit sample.

Unlike the Sound sample output registers, these can be written to - allowing for direct 16-bit sample output.

Hyper Voice Input ($69 write)

7  bit  0
---- ----
ssss ssss
|||| ||||
++++-++++- Signed 8-bit sample.

Hyper Voice samples are typically written by Sound DMA, but can also be written manually by the user. In the latter case, the "channel mode" setting is ignored - it always behaves as if it were in "stereo" mode, writing one channel after the other in sequence.

Hyper Voice Control ($6A, $6B)

15  bit  8  7  bit  0
 ---- ----  ---- ----
 .mmc ????  errr ffss
  |||       |||| ||||
  |||       |||| ||++- Shift/Volume:
  |||       |||| ||      0 = 100%   1 = 50%
  |||       |||| ||      2 = 25%    3 = 12.5%
  |||       |||| ++--- Sample scaling mode:
  |||       ||||         0 = Unsigned
  |||       ||||         1 = Unsigned, negated
  |||       ||||         2 = Signed
  |||       ||||         3 = Ignored
  |||       |+++------ Update sample rate/Divisor:
  |||       |            0 = 24000/1  = 24000 Hz
  |||       |            1 = 24000/2  = 12000 Hz
  |||       |            2 = 24000/3  =  8000 Hz
  |||       |            3 = 24000/4  =  6000 Hz
  |||       |            4 = 24000/5  =  4800 Hz
  |||       |            5 = 24000/6  =  4000 Hz
  |||       |            6 = 24000/8  =  3000 Hz
  |||       |            7 = 24000/12 =  2000 Hz
  |||       +--------- Enable: 0 = off, 1 = on
  ||+----------------- Reset: When 1 is written, the following DMA sample
  ||                          will be used for the left channel.
  ++------------------ Channel mode:
                         0 = Stereo
                         1 = Mono, left channel only
                         2 = Mono, right channel only
                         3 = Mono, both channels

Internally, 8-bit values of the form Vvvv vvvv are transformed to signed 16-bit samples based on the scaling mode as follows, where V represents the highest, 7th bit of the input value:

Sample scaling mode	Bit representation
Unsigned	000 Vvvv vvvv 0000 0000
Unsigned, negated	111 Vvvv vvvv 0000 0000
Signed	VVV Vvvv vvvv 0000 0000
Ignored	___ Vvvv vvvv 0000 0000

With the exception of the Ignored mode, the resulting value is shifted right by Shift bits, and the result's bottom 16 bits are used as the sample.