AD1985 Analog Devices, AD1985 Datasheet - Page 26

• Manufacturer Part Number: AD1985
• Description: AC'97 2.3 Soundmax Codec W/jack Sensing
• Manufacturer: Analog Devices

AD1985
Power-Down Control/Status Register (Index 0x26)
Reg Num
0x26
Note: The ready bits are read-only; writing to REF, ANL, DAC, ADC will have no effect. These bits indicate the status for the AD1985 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
DAC
ANL
REF
PR[6:0]
PR0
PR1
PR2
PR3
PR4
PR5
PR6
EAPD
Name
Power-Down Cntrl/Stat
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. Some bits can be used individually while others are used in combination.
ADCs and Input Mux Power-Down. Default setting is 0.
Clearing this bit will enable V
DACs Power-Down. Also powers down the EQ circuitry. Default setting is 0.
Clearing this bit will enable V
Mixer Power-Down. Default setting is 0.
Power Down V
May be used in combination with PR2 or by itself. If all the ADCs and DACs are not powered down setting this bit will have
no effect on the V
AC Link Interface Power-Down. Default setting is 0. 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 PR4 bit controls the slave codec. In the slave codec the PR4 bit has no effect
except to enable or disable PR5.
Internal Clocks Disabled. Default setting is 0.
PR5 has no effect unless all ADCs, DACs, and the AC Link are powered down (e.g., PR0, PR1, PR4). 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 controls the slave codec. PR5 is effective in the slave codec if
the master's PR5 bit is clear.
Powers Down the Headphone Amplifiers. Default setting is 0.
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.
NORMAL
PR0 = 1
ADC = 1
REF
PR0 = 0
READY = 1
AND
and V
REF
and will only power down V
ADCs OFF
REF
REFOUT
PR0
and V
D15
EAPD PR6 PR5 PR4 PR3 PR2 PR1 PR0 X
Figure 11. Example of AC ’97 Power-Down/Power-Up Flow
. Default setting is 0.
REF
REF
REFOUT
PR1 = 1
regardless of the state of PR3.
regardless of the state of PR3.
DAC = 1
PR1 = 0
D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2
AND
, up to nominal level.
DACs OFF
PR1
Rev. 0 | Page 26 of 48
DEFAULT
REFOUT
PR2 = 1
ANL = 1
PR2 = 0
AND
.
ANALOG
PR2 OR
OFF
PR3
PR4 = 1
RESET
RESET
WARM
COLD
DIGITAL I/F
X
OFF
PR4
X
X
REF ANL DAC ADC N/A
SHUT OFF
AC-LINK
D1
D0
Default