AD1981B Analog Devices, AD1981B Datasheet - Page 17

• Manufacturer Part Number: AD1981B
• Description: AD1981B AC'97 SoundMAX® Codec
• Manufacturer: Analog Devices

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.
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.
REV. A
ADC
DAC
ANL
REF
PR [6:0]
EAPD
Power-Down State
ADCs and Input Mux Power-Down
DACs Power-Down
Analog Mixer Power-Down (V
Analog Mixer Power-Down (V
AC-Link Interface Power-Down
Internal Clocks Disabled
ADC and DAC Power-Down
V
Total Power-Down
Headphone Amp Power-In Standby
Reg
No. Name
26h Power-Down Ctrl/Stat
Reg
No. Name
28h Ext’d Audio ID IDC1 IDC0 X
REF
Standby Mode
ADC Sections Ready to Transmit Data
DAC Sections Ready to Accept Data
Analog Amplifiers, Attenuators, and Mixers Ready
Voltage References, V
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.
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.
D15
D15
EAPD PR6
D14
REF
REF
D14
D13 D12 D11
and V
and V
REF
X
D13
PR5
REFOUT
REFOUT
Power-Down Control/Status Register (Index 26h)
, and V
REVC1 REVC0 AMAP
Extended Audio ID Register (Index 28h)
D12
PR4
On)
Off)
REFOUT
D11
PR3
D10
up to Nominal Level
PR2 PR1
D10 D9
Set Bits
PR0
PR1
PR1, PR2
PR0, PR1, PR3
PR4
PR0, PR1, PR4, PR5
PR0, PR1
PR0, PR1, PR2, PR4, PR5
PR0, PR1, PR2, PR3, PR4, PR5, PR6
PR6
D9
–17–
D8
PR0 X
D8
X
D7
D7
X
D6
X
D6
X
D5
X
D5
DSA1
D4
X
D4
DSA0
D3
REF
D3 D2
X
D2
ANL
SPDF X
D1
DAC
PR [6:0]
[000 0001]
[000 0010]
[000 0101]
[000 1011]
[001 000]
[011 0011]
[000 0011]
[011 0111]
[111 1111]
[100 0000]
D1 D0
AD1981B
D0
ADC
VRAS X605h
Default
000Xh
Default