Audio Muting - Analog Devices ADV7610 Hardware User's Manual

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AUDIO MUTING

The ADV7610 integrates an advanced audio mute function that is designed to remove all extraneous noise and pops from a 2-channel
L-PCM audio stream at sample frequencies up to 48 kHz.
The hardware for audio mute function is composed of the following three blocks:
•
Audio delay line that delays Channel 1 and Channel 2 by 512 stereo samples.
•
Audio mute controller takes in event detection signals that can be used to determine when an audio mute is needed. The controller
generates a mute signal to the ramped audio block and a coast signal to the digital PLL generating the audio clock.
•
Ramped audio mute block that can mute the audio over the course of 512 stereo samples.
Note that the ADV7610 mutes only the noncompressed data from the audio sample packets output through the I
interface.
Delay Line Control
The audio delay line should be enabled when the
MAN_AUDIO_DL_BYPASS
MAN_AUDIO_DL_BYPASS, Addr 68 (HDMI), Address 0x0F[7]
Audio delay bypass manual enable. The audio delay line is automatically active for stereo samples and bypassed for multichannel samples.
By setting MAN_AUDIO_DL_BYPASS to 1, the audio delay bypass configuration can be set by the user with the AUDIO_DELAY_
LINE_BYPASS control.
Function
MAN_AUDIO_DL_BYPASS
0 (default)
1
AUDIO_DELAY_LINE_BYPASS, Addr 68 (HDMI), Address 0x0F[6]
Manual bypass control for the audio delay line. Only valid if MAN_AUDIO_DL_BYPASS is set to 1.
Function
AUDIO_DELAY_LINE_BYPASS
0 (default)
1
Audio Mute Configuration
The ADV7610 can be configured to automatically mute an L-PCM audio stream when selectable mute conditions occur. The audio
muting is configured as follows:
•
Set the audio muting speed via AUDIO_MUTE_SPEED[4:0].
•
Set NOT_AUTO_UNMUTE, as follows:
•
Set AUDIO_UNMUTE[2:0] to 0 if the audio must be unmuted automatically after a delay set in
selected mute conditions have become inactive.
•
Set NOT_AUTO_UNMUTE to 1 if the audio must be unmuted manually (for example, by an external controller) when all
selected mute conditions have become inactive.
•
Select the mute conditions that trigger an audio mute (refer to Table 14).
•
Select the Audio PLL coast conditions (refer to the Audio DPLL Coast Feature section).
•
Set WAIT_UNMUTE[2:0]
mute conditions have become inactive.
The ADV7610 internally unmutes the audio if the following three conditions (listed in order of priority) are met:
•
Mute conditions are inactive.
•
NOT_AUTO_UNMUTE
•
Audio unmute counter has finished counting down or is disabled.
ADV7610
and AUDIO_DELAY_LINE_BYPASS
Description
Audio delay line is automatically bypassed if multichannel audio is received. The audio delay line is
automatically enabled if stereo audio is received.
Overrides automatic bypass of audio delay line. Audio delay line is applied depending on the
AUDIO_DELAY_LINE_BYPASS control.
Description
Enables the audio delay line
Bypasses the audio delay line
to configure the audio counter that triggers the audio unmute when it has timed out after all selected
is set to 0.
is configured for automatic mute. The audio delay line is controlled by the
bits.
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Hardware User Guide
2 S and the SPDIF
WAIT_UNMUTE[2:0] after all