STV8216 datasheet(20/97 Pages) STMICROELECTRONICS

20 / 97 page

Audio Processor Block

STV82x6

20/97

features dedicated to various kinds of music, to implement programmable Loudness or Super-bass

functions. The Headphone Bass/Treble feature is enabled by setting the BT_ON bit in the

HP_BT_CTRL register. The Bass and Treble gain values are adjusted in registers HP_BASS_GAIN

and HP_TREBLE_GAIN, respectively.

3.6

Volume/Balance Control

The STV82x6 provides a Volume/Balance Control for each of the Loudspeaker, Subwoofer and

Headphone audio outputs. Its wide range (from 0 to -96 dB in a linear scale) largely covers typical

home applications (approx. 60 dB) while maintaining a good S/N ratio. Its fine resolution (0.375 dB)

provides simple volume programming and a relative OSD scale representation. The Loudspeaker,

Subwoofer and Headphone volume values should be programmed progressively in steps of less

than 1 dB in order to prevent audible envelope variations and a minimum duration of 16 ms is

required between two successive programming commands to guarantee that there are no audible

plops during volume changes. In this case, a full 8-bit volume scan with minimum steps of 0.375 dB

will last approximately 4 s (minimum).

The Volume/Balance Control can operate in one of two different modes:

● In Differential mode (default value), the volume control is a common volume value for both the

Left and Right Loudspeaker and Headphone channels.

● In Independent mode, the volume for the Left and Right channels for Loudspeakers or

Headphone is controlled independently.

As the Loudspeaker bass frequencies are output by the Subwoofer, its reference volume is

controlled by default with the value of the LS_CVOL common volume register. The SW_GAIN

Independent mode, the SW_GAIN register is used as a separated volume control and does not take

into account the Loudspeaker audio level.

3.6.1

Differential Mode

The common value for the Right/Left volume controls for the Loudspeaker, Subwoofer and

Headphone outputs are programmed in registers LS_CVOL, SW_GAIN and HP_CVOL,

respectively. A differential balance can be applied using registers LS_BAL and HP_BAL to adjust

the Left/Right level ratio as shown in Figure 12.

Figure 11: Volume Control

0dB

-96 dB

Mute

00h

FFh

I²C Control

STV8216 Folha de dados(PDF) 20 Page - STMicroelectronics