WM8716EDS データシートの表示（PDF） - Wolfson Microelectronics plc
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WM8716EDS Datasheet PDF : 21 Pages
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Production Data
MUTE MODES
WM8716
The device has various mute modes.
DIGITAL FILTER
Reg bit OPE = ‘1’
Unaffected
MUTEB pin
Gain ramped to zero
On release volume ramps
to previous value
AUTOMUTE
(detect 1024 zero
input samples)
Automute has no effect on digital
filters
Reg bit MUT
Gain = 00
(left & right)
As MUTEB pin
Gain = -∞dB
RAM initialise
Gain initialised to 0dB
Loss of system
clock
Not running (no clock). On clock
restart, filters initialised, RAM
initialised. Registers unchanged
No LRCLK or invalid Filters initialised, RAM initialised.
SCLK/LRCLK ratio Registers unchanged
RB
Power-on reset
Reset – gain initialised to 0dB
Reset
Table 21 Mute Modes
ANRES
ANALOGUE
ANMUTE
Asserted
Asserted when
gain = 0
Asserted
Asserted after
1024 zero input
samples if IZD = 1
As MUTEB pin
Asserted
Asserted
Asserted
Asserted Asserted
Asserted
Asserted
Asserted
Asserted
• ANRES is the reset to the switched capacitor filter.
• ANMUTE is an analogue muting signal gating the analogue signal at the output (after the
SC filter)
• AUTOMUTE is asserted when both the IZD register bit is asserted and the input audio data has
been zero on both left and right channels for 1024 input samples. The first non-zero sample de-
asserts.
• Applying a logic low to MUTEB or setting MUT in Reg2 causes the gain registers to ramp to zero.
When a logic high is applied, the gain ramps slowly back up to the value held in the appropriate
attenuation register (AL or AR). The ramp rate = 128/fs s/0.5dB step.
MUTEB
SOFTMUTE
GAINL[0:7]
GAINR[0:7]
If SOFTMUTE is set or
MUTEB=0 then GAINL and
GAINR are overridden to 00
Signal
Processing
gain ramps between
previous and new gain
setting
Automute:
Detect 1024
zero input
samples
IZD
ZERO
OPE
FREQ_INVALID
INIT
ANMUTE
Figure 7 Mute Modes
WOLFSON MICROELECTRONICS LTD
PD Rev 3.1 April 2001
15
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