wm9704m Wolfson Microelectronics plc, wm9704m Datasheet - Page 27

• Manufacturer Part Number: wm9704m
• Description: Amc97 Audio Modem Codec
• Manufacturer: Wolfson Microelectronics plc

Production Data
POWERDOWN CONTROL/STATUS REGISTER (INDEX 26H)
WOLFSON MICROELECTRONICS LTD
3D CONTROL REGISTER (INDEX 22H)
This register is used to control the centre and/or depth of the 3D stereo enhancement function built
into of the AC ‘97 component. Only the depth bits DP0 to 3 have effect in the WM9704M.
RESERVED REGISTER (INDEX 24H)
This register was originally specified to control what sample rate AC’97 is sending or receiving
samples for the optional modem in and out. Not supported by the WM9704M.
This read/write register is used to program powerdown states and monitor subsystem readiness. The
lower half of this register is read only status, a 1 indicating that the subsection is “ready”. Ready is
defined as the subsection able to perform in its nominal state. When this register is written the bit
values that come in on AC-link will have no effect on read only bits 0 to 7.
When the AC-link “Codec Ready” indicator bit (SDATA_IN slot 0, bit 15) is a 1 it indicates that the
AC-link and the WM9704M control and status registers are in a fully operational state. The AC’97
controller must further probe this Powerdown Control/Status Register to determine exactly which
subsections, if any, are ready.
Table 16 Powerdown Status Register Function
The powerdown modes are as follows. 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. PR0
and PR1 control the PCM ADCs and DACs only. PR6 is not supported by the WM9704M.
Table 17 Powerdown Control Register Function
WRITE BIT
READ BIT
EAPD
DAC
ADC
REF
ANL
PR0
PR1
PR2
PR3
PR4
PR5
PR6
DP3…DP0
15
0
1
8
-
-
FUNCTION
VREFs up to nominal level
Analogue mixers, etc ready
DAC section ready to accept data
ADC section ready to transmit data
FUNCTION
PCM in ADCs and input Mux powerdown
PCM out DACs powerdown
Analogue mixer powerdown (VREF still
on)
Analogue mixer powerdown (VREF off)
Digital interface (AC-link) powerdown
(external clock off)
Internal clock disable
HP amp powerdown – not supported
External amplifier powerdown
Typical value
DEPTH
100%
0%
PD Rev 3.2 January 2001
WM9704M
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