AD1881A
Subsection Ready Register (Index 26h)
Reg
Name
D15
D14 D13 D12 D11 D10 D9
D8
D7 D6 D5 D4 D3
D2
D1
D0
Default
Num
26h
Power-Down Cntrl/Stat EAPD
X
PR5 PR4 PR3 PR2 PR1 PR0
X
X
X
X
REF ANL DAC ADC N/A
Note: The ready bits are read only, writing to REF, ANL, DAC, ADC will have no effect. These bits indicate the status for the
AD1881A subsections. If the bit is a one, then that subsection is “ready.” Ready is defined as the subsection able to perform in its
nominal state.
ADC
DAC
ANL
ADC section ready to transmit data.
DAC section ready to accept data.
Analog gain, attenuators and mute blocks, and mixers ready.
Voltage References, VREF and VREFOUT up to nominal level.
REF
PR[5:0]
AD1881A Power-Down Modes. The first three bits are to be used individually rather than in combination with each
other. The last bit 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
either be 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 Amp Power Down. Available when programmed as an AC’97 codec.
0 = Pin 47 set to LO state (default).
1 = Pin 47 set to HI state.
Power-Down State
PR5 PR4 PR3 PR2 PR1 PR0
ADC Power-Down
DAC Power-Down
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
1
0
0
0
1
1
1
1
1
0
1
1
0
0
1
1
1
1
0
1
0
1
0
1
1
ADC and DAC Power-Down
Mixer Power-Down
ADC + Mixer Power-Down
DAC + Mixer Power-Down
ADC + DAC + Mixer Power-Down
Standby
Extended Audio ID Register (Index 28h)
Reg
Name
D15 D14 D13 D12 D11 D10 D9
ID1 ID0
D8
X
D7
X
D6
X
D5
X
D4
D3
X
D2
X
D1
X
D0
Default
Num
28h
Extended Audio ID
X
X
X
X
X
X
VRA 0000h
Note: The Extended Audio ID is a read only register.
VRA
Variable Rate Audio. VRA = 1 enables Variable Rate Audio.
ID[1:0]
ID1, ID0 is a 2-bit field that indicates the codec configuration: Primary is 00; Secondary is 01, 10, or 11.
REV. 0
–17–
ADI [ ADI ]
