Datasheet

TAS5548
www.ti.com 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
register. When HP_SEL is high, the channel-1 and -2 configuration registers define the configuration of
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 I
2
C 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 I
2
C 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.
Copyright © 2012, Texas Instruments Incorporated TAS5548 Controls and Status 39
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