WM8281ECSSLASHR datasheet(72/392 Pages) CIRRUS

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WM8281

Rev 4.0

ADDRESS

BIT

LABEL

DEFAULT

DESCRIPTION

R707

(02C3h)

Mic noise

mix control

MICMUTE_NOIS

E_ENA

Mic Mute Mixer Control

0 = Mic Mix

1 = Noise Mix

MICMUTE_MIX_

ENA

Mic Mute Mixer Enable

0 = Disabled

1 = Enabled

Table 9 Mic Mute Mixer Control Registers

The WM8281 performs automatic checks to confirm that the SYSCLK frequency is high enough to

support the commanded digital mixing functions. If an attempt is made to enable a MICMIX or

NOISEMIX signal path, and there are insufficient SYSCLK cycles to support it, then the attempt will be

unsuccessful. (Note that any signal paths that are already active will not be affected under these

circumstances.)

The Underclocked Error condition can be monitored using the GPIO and/or Interrupt functions. See

“General Purpose Input / Output” and “Interrupts” for further details.

The status bits in Registers R1600 to R3000 indicate the status of each of the digital mixers. If an

Underclocked Error condition occurs, then these bits provide readback of which mixer(s) have been

successfully enabled, and which mixer(s) could not be enabled.

5-BAND PARAMETRIC EQUALISER (EQ)

The digital core provides four EQ processing blocks as illustrated in Figure 29. A 4-input mixer is

associated with each EQ. The 4 input sources are selectable in each case, and independent volume

control is provided for each path. Each EQ block supports 1 output.

The EQ provides selective control of 5 frequency bands as described below.

The low frequency band (Band 1) filter can be configured either as a peak filter or a shelving filter.

When configured as a shelving filter, is provides adjustable gain below the Band 1 cut-off frequency.

As a peak filter, it provides adjustable gain within a defined frequency band that is centred on the

Band 1 frequency.

The mid frequency bands (Band 2, Band 3, Band 4) filters are peak filters, which provide adjustable

gain around the respective centre frequency.

The high frequency band (Band 5) filter is a shelving filter, which provides adjustable gain above the

Band 5 cut-off frequency.

EQnMIX_VOL2

EQnMIX_VOL3

EQnMIX_VOL4

EQnMIX_VOL1

EQnMIX_SRC1

EQnMIX_SRC3

EQnMIX_SRC4

EQnMIX_SRC2

EQ1 (50h)

EQ2 (51h)

EQ3 (52h)

EQ4 (53h)

5-band Equaliser

WM8281 supports 4 EQ blocks, ie. n = 1, 2, 3 or 4

Figure 29 Digital Core EQ Blocks

WM8281ECS/R Datasheet(PDF) 72 Page - Cirrus Logic

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