REV. 0

AD1981A

–14–

Power-Down Control/Status Register (Index 26h)

NOTES

The ready bits are read only; writing to REF, ANL, DAC, ADC will have no effect. These bits indicate the status for the AD1981A subsections.

If the bit is a “1” then that subsection is “ready.” Ready is defined as the subsection able to perform in its nominal state.

ADC

ADC sections ready to transmit data

DAC

DAC sections ready to accept data

ANL

Analog amplifiers, attenuators, and mixers ready

REF

PR[6:0]

CODEC Power-Down Modes. The first 3 bits are to be used individually rather than in combination with each

other. PR3 can be used in combination with PR2 or by itself. The mixer and reference cannot be powered down

via PR3 unless the ADCs and DACs are also powered down.

Nothing else can be powered up until the reference is up. PR5 has no effect unless all ADCs, DACs, and the AC Link

are powered down. The reference and mixer can be either up or down, but all power-up sequences must be allowed

to run to completion before PR5 and PR4 are both set.

In multiple-codec systems, the master CODEC’s PR5 and PR4 bits control the slave CODEC. PR5 is also effective

in the slave CODEC if the master’s PR5 bit is clear, but the PR4 bit has no effect except to enable or disable PR5.

EAPD

External Audio Power-Down Control: Controls the state of the EAPD Pin

EAPD = 0 sets the EAPD Pin low, enabling an external power amplifier (reset default).

EAPD = 1 sets the EAPD Pin high, shutting the external power amplifier off.

Power-Down State

Set Bits

ADCs and Input Mux Power-Down

PR0

DACs Power-Down

PR1

PR1, PR2

PR0, PR1, PR3

AC-Link Interface Power-Down

PR4

Internal Clocks Disabled

PR0, PR1, PR4, PR5

ADC and DAC Power Down

PR0, PR1

PR0, PR1, PR2, PR4, PR5

Total Power-Down

PR0, PR1, PR2, PR3, PR4, PR5

Headphone Amp Power in Standby

PR6

Extended Audio ID Register (Index 28h)

REG NAME

D15 D14 D13 D12

D11

D10

D9

D8 D7 D6

D5

D4

D3

D2

D1

D0 Default

28h

Ext’d Audio ID

ID1 ID0

X

X

REV1 REV0 AMAP X

X

X

DSA1 DSA0 X

SPDIF X

VRA X605h

The extended audio ID register identifies which extended audio features are supported. A non-zero extended audio ID value indicates one or

more of the extended audio features are supported.

Reg Num Name

D15

D14 D13 D12 D11 D10 D9

D8 D7 D6 D5 D4

D3

D2

D1

D0

Default

26h

Power-Down Cntrl/Stat

EAPD PR6 PR5 PR4 PR3 PR2 PR1 PR0 XXXX REF ANL DAC ADC 000Xh