WM8731 Wolfson Microelectronics Ltd., WM8731 Datasheet - Page 42

• Manufacturer Part Number: WM8731
• Description: WM8731 : Low Power Audio Codec With Integrated Headphone Driver
• Manufacturer: Wolfson Microelectronics Ltd.

WM8731
ACTIVATING DSP AND DIGITAL AUDIO INTERFACE
SOFTWARE CONTROL INTERFACE
The exact sample rates supported for all combinations are defined by the relationships in Table 21
below.
To prevent any communication problems from arising across the Digital Audio Interface the Audio
Interface is disabled (tristate with weak 100k pulldown). Once the Audio Interface and the Sampling
Control has been programmed it is activated by setting the ACTIVE bit under Software Control.
Table 22 Activating DSP and Digital Audio Interface
It is recommended that between changing any content of Digital Audio Interface or Sampling Control
Register that the active bit is reset then set.
The software control interface may be operated using either a 3-wire (SPI-compatible) or 2-wire MPU
interface. Selection of interface format is achieved by setting the state of the MODE pin.
In 3-wire mode, SDIN is used for the program data, SCLK is used to clock in the program data and
CSB is used to latch in the program data. In 2-wire mode, SDIN is used for serial data and SCLK is
used for the serial clock. In 2-wire mode, the state of CSB pin allows the user to select one of two
addresses.
SELECTION OF SERIAL CONTROL MODE
The serial control interface may be selected to operate in either 2 or 3-wire modes. This is achieved
by setting the state of the MODE pin.
Table 23 Control Interface Mode Selection
Table 21 USB Mode Actual Sample Rates
0001001
Active Control
SAMPLING
TARGET
RATE
REGISTER
the data across the digital interface is correctly synchronised at the 8.021kHz and 44.117kHz
rates.
ADDRESS
kHz
44.1
88.2
32
48
96
8
MODE
0
1
12MHz/(250 x 48/32)
12MHz/(250 x 48/8)
not available
not available
0
BOSR=0
12MHz/250
12MHz/125
( 250fs)
BIT
kHz
32
48
96
ACTUAL SAMPLING RATE
8
ACTIVE
LABEL
INTERFACE
FORMAT
2 wire
3 wire
12MHz/(272 x 11/2)
0
not available
not available
not available
DEFAULT
BOSR=1
12MHz/272
12MHz/136
(272fs)
44.117
88.235
8.021
kHz
Activate Interface
1 = Active
0 = Inactive
DESCRIPTION
AI Rev 2.3 August 2001
Advanced Information
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