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Table IV. Control Register 1 READ Definition

Function

1DSP Core Shutdown Complete

1 = Shutdown Complete

0 = Not Shut Down

Safe Memory Load Complete

1 = Complete (Note: Cleared after Read)

0 = Not Complete

Bit 0 is asserted when all requested safeload registers have been

transferred to the parameter RAM. It is cleared after the read

operation is complete.

Bit 1 is asserted after the requested shutdown of the DSP is

completed. When this bit is set, the user is free to write or read

any RAM location without causing an audio pop or click.

Table V. Control Register 2 WRITE Definition

Function

9Volume Ramp Speed

1 = 160 ms Full-Ramp Time

0 = 20 ms Full-Ramp Time

Serial Port Output Enable

1 = Enabled

0 = Disabled

7:6

Serial Port Input Select

00 = IN0

01 = IN1

10 = IN2

11 = NA

5:4

MCLK Input Select

00 = MCLK0

01 = MCLK1

10 = MCLK2

11 = NA

3Reserved

MCLK In Frequency Select

0 = 512

× f

1 = 256

× fS

1:0

MCLK Out Frequency Select

00 Disabled

01 512

× fS

10 256

× f

11 MCLKO = MCLK_In (Feedthrough)

Control Register 2

Table V documents the contents of Control Register 2. Bits

<1:0> set the frequency of the MCLKO pin. If these bits are set

to 00, the MCLKO pin is disabled (default). When set to 01,

the MCLKO pin is set to 512

× f

S, which is the same as the

internal master clock used by the DSP core. When set to 10,

this pin is set to 256

× fS, derived by dividing the internal DSP

clock by 2. In this mode, the output 256

× f

S clock will be inverted

with respect to the input 256

× f

S clock. This is not the case with

the feedthrough mode. When set to 11, the MCLKO pin mirrors

the selected MCLK input pin (it’s the output of the MCLK

MUX selector). Note that the internal DSP master clock may

either be the same as the selected MCLK pin (when MCLK

frequency select is set to 512

× f

S mode) or may be derived from

the MCLK pin using internal clock doubler (when MCLK fre-

quency select is set to 256

× fS).

Bit <2> selects one of two possible MCLK input frequencies. When

set to 0 (default), the MCLK frequency is set to 512

× f

S. In this mode,

the internal DSP clock and the external MCLK are at the same

frequency. When set to 1, the MCLK frequency is set to 256

× fS, and

an internal clock doubler is used to generate the DSP clock.

Bits <5:4> select one of three clock input sources using an inter-

nal MUX. To avoid click and pop noises when switching MCLK

sources, it is recommended that the user put the DSP core in

shutdown before switching MCLK sources.

Bits <7:6> select one of three serial input sources using an inter-

nal MUX. Each source selection includes a separate SDATA,

LRCLK, and BCLK input. To avoid click and pop noises when

switching serial sources, it is recommended that the user put the

DSP core in shutdown before writing to these bits.

Bit <8> is used to enable the three serial output pins. These pins

are connected to the output of the serial input MUX, which is set

by Bits <7:6>. The default is 0 (disabled).

Bit <9> changes the default setting of the volume ramp speed.

When set to 0, it will take 1024 LRCLK periods to go from full

volume (6 dB) to infinite attention. When set to 1, the same

operation will take 8192 LRCLK periods.

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