AD1885 Datasheet, PDF (18/27 Pages) Analog Devices – AC’97 SoundMAX Codec

AD1885
Subsection Ready Register (Index 26h)
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 X X X X REF ANL DAC ADC 000xh
Note: The ready bits are read only, writing to REF, ANL, DAC, ADC will have no effect. These bits indicate the status for the
AD1885 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
ADC section ready to transmit data.
DAC
DAC section ready to accept data.
ANL
Analog gainuators, attenuators, and mixers ready.
REF
Voltage References, VREF and VREFOUT up to nominal level.
PR[5:0]
AD1885 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.
PR0 – Power-Down ADC
PR1 – Power-Down DAC
PR2 – Power-Down Analog Mixer
PR3 – Power-Down V_REF and V_REFOUT
PR4 – Power-Down AC-Link
PR5 – Power-Down Internal Clock
PR6 – Power-Down Headphone
EAPD – External AMP Power-Down Control Signal
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.
Power-Down State
ADC Power-Down
DAC Power-Down
ADC and DAC Power-Down
Mixer Power-Down
ADC + Mixer Power-Down
DAC + Mixer Power-Down
ADC + DAC + Mixer Power-Down
Standby
EAPD PR6
X
0
X
0
X
0
X
0
X
0
X
0
X
0
X
1
PR5 PR4 PR3 PR2 PR1 PR0
0
0
0
0
0
1
0
0
0
0
1
0
0
0
0
0
1
1
0
0
0
1
0
0
0
0
0
1
0
1
0
0
0
1
1
0
0
0
0
1
1
1
1
1
1
1
1
1
Extended Audio ID Register (Index 28h)
Reg
Num
Name
D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 Default
28h Extended Audio ID ID1 ID0 X X X X X X X X X X X X X VRA 0001h
Note: The Extended Audio ID is a read only register.
VRA
Variable Rate Audio. VRA = 1 indicates support for Variable Rate Audio.
ID[1:0]
ID1, ID0 is a 2-bit field that indicates the codec configuration: Primary is 00; Secondary is 01.
–18–
REV. 0