TAS5548 datasheet(39/120 Pages) TI

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TAS5548

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SLES270 – NOVEMBER 2012

5.2.4

Speaker/Headphone Selector (HP_SEL)

The HP_SEL terminal enables the headphone output or the speaker outputs. The headphone output

receives the processed data output from DAP and PWM channels 1 and 2.

In 6-channel configuration, this feature does not affect the two lineout channels.

When low, the headphone output is enabled. In this mode, the speaker outputs are disabled. When high,

the speaker outputs are enabled and the headphone is disabled.

Changes in the pin logic level result in a state change sequence using soft mute (PWM switching at 50/50,

noise shaper on) to the hard mute (non-PWM switching) mode for both speaker and headphone followed

by a soft unmute.

When HP_SEL is low, the configuration of channels 1 and 2 is defined by the headphone configuration

channels 1 and 2.

If using the remapped-output mixer configuration (0xD0 bit 30 = 0) in the 6-channel mode, the headphone

operation is modified. That is, following the assertion or de-assertion of headphone, mute must be

asserted and de-asserted using the MUTE pin.

5.2.5

Mute (MUTE)

The mute control provides a noiseless volume ramp to silence. Releasing mute provides a noiseless ramp

to previous volume. The TAS5548 has both master and individual channel mute commands. A terminal is

also provided for the master mute. The master mute I2C register and the MUTE terminal are logically

ORed together. If either is asserted, a mute on all channels is performed. The master mute command

operates on all channels regardless of whether the system is in the 6- or 8-channel configuration. PWM is

switching at 50% duty cycle during mute.

The master mute terminal is used to support a variety of other operations in the TAS5548, such as setting

the biquad coefficients, the serial interface format, and the clock rates. A mute command by the master

mute terminal, individual I2C mute, the AM interference mute sequence, the bank-switch mute sequence,

or automute overrides an unmute command or a volume command. While a mute is active, the

commanded channels are placed in a mute state. When a channel is unmuted, it goes to the last

commanded volume setting that has been received for that channel.

TAS5548 Controls and Status

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