STV8247 datasheet(39/156 Pages) STMICROELECTRONICS

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STV82x7

Dedicated Digital Signal Processor (DSP)

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

Headphone is controlled independently.

Note:

Each step is 0.25 dB

4.14

Soft Mute Control

The Digital Soft Mute is applied smoothly (20 ms for 120 dB range) to avoid any switch noise on

output. It is available on all output channels pairs:

● S/PDIF channel (Left/Right)

● SCART channels (Left/Right)

● Loudspeakers channels (Left/Right)

● Center

● Subwoofer

● Headphone/Surround channels (Left/Right)

Another soft mute (analog) is also available on each DAC output.

4.15

Beeper

The beeper is used to generate a tone on the Loudspeakers or/and Headphone outputs. The

beeper sound (square wave) is added to the audio signal which is attenuated by 20 dB. The beep

sound amplitude includes a smooth attack and decay to avoid any parasitic noise when starting and

stopping.

It can be used for various applications such as beep sounds for remote control, alarm clock or other

features.

The Beeper operates in one of two modes:

● Pulse mode (beep applications): A tone with a programmable short duration (0.1, 0.25, 0.5

and 1.0 s) is generated. Afterwards, the beeper is automatically disabled and the output is

switched back to the audio signal, see Figure 22.

● Continuous mode (alarm application): A tone with a programmable long duration is

generated. Its start and stop controls must be programmed by I²C, see Figure 23.

The Beeper function is enabled by setting the BEEPER_ON bit in register BEEPER_ON.

Beeper parameters are controlled in register BEEPER_MODE.

Figure 21: Differential Balance

100%

Mute

200h

1FFh

I²C Control (10 bits)

000h

STV8247 Datasheet(PDF) 39 Page - STMicroelectronics