STV8216 datasheet(27/97 Pages) STMICROELECTRONICS

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STV82x6

Additional Controls and Flags

5.1

Interrupt Request

The identified TV sound standard is displayed in register AUTO_STAT. Each change in the detected

standard is flagged to the host system via hardware pin IRQ. The flag must be reset by re-

programming the IRQ bit in register AUTO_CTRL and then checking the detected standard status

by reading registers AUTO_STAT, NICAM_STAT, ZWT_STAT and CH_MX.

5.2

I²C Bus Expander

Pins BUS0 and BUS1 can be used to control external switchable IF SAW filters or audio switches.

These pins can be directly programmed by register CTRL.

5.3

Stereo Flag

For Loudspeakers only, a Stereo Mode Detection flag (the ST_ID bit in register AUTO_STAT) is set

when a demodulated source is selected and a stereo standard is detected. The stereo flag is also

output on pin ST in order to control an external indicator (e.g. LED). The stereo mode is also

displayed by status register AUTO_STAT.

CAUTION: When the I²S input is selected, the stereo flag is no longer available on pin ST.

5.4

Headphone Detection

For the headphone, the HPD input can be used to automatically mute the Loudspeaker and

Subwoofer outputs when the HPD_ON bit is set in register ANA_LS_HP (active low). The HPD pin

must be set for the mute function to be active.

Figure 16: Headphone Detection

Mute Control

Headphone

Left

Right

Sub-

I²C Control

STV82x6

Loudspeaker

Audio Processing

Headphone

Audio Processing

Subwoofer

Audio Processing

woofer

Detection

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