wm9707scft-v Wolfson Microelectronics plc, wm9707scft-v Datasheet - Page 28

• Manufacturer Part Number: wm9707scft-v
• Description: Ac?97 Revision 2.1 Audio Codec With Spdif Output
• Manufacturer: Wolfson Microelectronics plc

WM9707
REVISION 2.1 REGISTERS (INDEX 28h T0 58h)
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The part will remain in sleep mode with all its registers holding their static values. To wake up the
WM9707, the AC’97 controller will send a pulse on the sync line issuing a warm reset. This will
restart the WM9707’s digital interface (resetting PR4 to 0). The WM9707 can also be woken up with
a cold reset. A cold reset will cause a loss of values of the registers, as a cold reset will set them to
their default states. When a section is powered back on, the Powerdown Control/Status Register
(index 26h) should be read to verify that the section is ready (i.e. stable) before attempting any
operation that requires it.
Figure 17 The WM9707 Powerdown/Flow with Analogue Still Alive
Figure 17 illustrates a state when all the mixers should work with the static volume settings that are
contained in their associated registers. This is used when the user could be playing a CD (or external
LINE_IN source) through WM9707 to the speakers but have most of the system in low power mode.
The procedure for this follows the previous except that the analogue mixer is never shut down.
POWERDOWN CONTROL/STATUS REGISTER (INDEX 26h)
Note that in order to go into ultimate low power mode, PR4 and PR5 are required to be set which
turns off the oscillator circuit. Asserting SYNC resets the PR4 and PR5 bit and re-starts the oscillator
in the same was as the AC link is restarted. Note that PR4 is redundant in slave mode.
These registers are specified as to use in Revision 2.1 of the AC’97 specification and have the
following functions on the WM9707:
REGISTER 28h – EXTENDED AUDIO ID
The Extended Audio ID register is a read only register that identifies which extended audio features
are supported (in addition to the original AC’97 features identified by reading the reset register at
index 00h). A non zero value indicates the feature is supported.
Table 13 Extended Audio ID Register
DATA BIT
CDAC
SDAC
AMAP
LDAC
DRA
VRM
VRA
ID1
ID0
ADCs OFF
PR0
PR1 = 0 AND
FUNCTION
Variable rate audio support
Double rate audio support
Variable rate Mic ADC support
Centre DAC support
Surround DAC support
LFE DAC support
Slot to front DAC mapping support
CODEC configuration – fixed in 9707
CODEC configuration – pin 45 value
DAC = 1
PR1 = 1
DACs OFF
PR1
PR2 = 0 AND
PR2 = 1
ANL = 1
ANALOGUE
OFF PR2
OR PR3
PR4 = 1
WARM RESET
DIGITAL I/F
OFF PR4
1 (Inverse of level at pin 45)
ANY MODE
PD, Rev 4.4, March 2009
1
0
0
0
0
0
0
0
CODA LINK
SHUT OFF
Production Data
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