REV. B

AD1981B

–17–

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 three 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 the 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

PR [6:0]

ADCs and Input Mux Power-Down

PR0

[000 0001]

DACs Power-Down

PR1

[000 0010]

PR1, PR2

[000 0101]

PR0, PR1, PR3

[000 1011]

AC-Link Interface Power-Down

PR4

[001 000]

Internal Clocks Disabled

PR0, PR1, PR4, PR5

[011 0011]

ADC and DAC Power-Down

PR0, PR1

[000 0011]

PR0, PR1, PR2, PR4, PR5

[011 0111]

Total Power-Down

PR0, PR1, PR2, PR3, PR4, PR5, PR6

[111 1111]

Headphone Amp Power-In Standby

PR6

[100 0000]

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

Reg

No. Name

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Default

26h Power-Down Ctrl/Stat

EAPD

PR6

PR5

PR4

PR3

PR2

PR1

PR0

X

X

X

X

REF

ANL

DAC

ADC

000Xh

The ready bits are read-only; writing to REF, ANL, DAC, ADC will have no effect. These bits indicate the status for the AD1981B subsections. If the bit is a 1, that

subsection is ready. Ready is defined as the subsection able to perform in its nominal state. All registers not shown and bits containing an X are assumed to be reserved.

Extended Audio ID Register (Index 28h)

Reg

No. Name

D15

D14

D13

D12

D11

D10

D9

D8

D7

D6

D5

D4

D3

D2

D1

D0

Default

28h Ext’d Audio ID IDC1 IDC0

X

X

REVC1

REVC0

AMAP

X

X

X

DSA1

DSA0

X

SPDIF X

VRAS

X605h

The Extended Audio ID Register identifies which extended audio features are supported. A nonzero Extended Audio ID value indicates that one or more of the

extended audio features are supported. All registers not shown and bits containing an X are assumed to be reserved.