wm8918 Wolfson Microelectronics plc, wm8918 Datasheet - Page 89

• Manufacturer Part Number: wm8918
• Description: Ultra Low Power Dac For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

Production Data
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Note that the WM8918 is a 24-bit device. In 32-bit mode (AIF_WL=11), the 8 LSBs are ignored on
the receiving side and not driven on the transmitting side.
AUDIO INTERFACE OUTPUT TRI-STATE
Register bit AIF_TRIS can be used to tri-state the audio interface pins as described in Table 51. All
digital audio interface pins will be tri-stated by this function, regardless of the state of other registers
which control these pin configurations.
Table 51 Digital Audio Interface Tri-State Control
BCLK AND LRCLK CONTROL
The audio interface can be programmed to operate in master mode or slave mode using the
BCLK_DIR and LRCLK_DIR register bits. In master mode, the BCLK and LRCLK signals are
generated by the WM8918 when any of the DMICs or DACs is enabled. In slave mode, the BCLK
and LRCLK clock outputs are disabled by default to allow another digital audio interface to drive
these pins.
It is also possible to force the BCLK or LRCLK signals to be output using BCLK_DIR and
LRCLK_DIR, allowing mixed master and slave modes. The BCLK_DIR and LRCLK_DIR fields are
defined in Table 52.
R25 (19h)
Audio
Interface 1
R25 (19h)
Audio
Interface 1
R26 (1Ah)
Audio
Interface 2
REGISTER
REGISTER
ADDRESS
ADDRESS
BIT
4:0
BIT
6
8
BCLK_DIR
BCLK_DIV
AIF_TRIS
LABEL
LABEL
[4:0]
DEFAULT
DEFAULT
0_0100
0
0
Audio Interface Tristate
0 = Audio interface pins operate normally
1 = Tristate all audio interface pins
Audio Interface BCLK Direction
0 = BCLK is input
1 = BCLK is output
BCLK Frequency (Master Mode)
00000 = SYSCLK
00001 = SYSCLK / 1.5
00010 = SYSCLK / 2
00011 = SYSCLK / 3
00100 = SYSCLK / 4 (default)
00101 = SYSCLK / 5
00110 = SYSCLK / 5.5
00111 = SYSCLK / 6
01000 = SYSCLK / 8
01001 = SYSCLK / 10
01010 = SYSCLK / 11
01011 = SYSCLK / 12
01100 = SYSCLK / 16
01101 = SYSCLK / 20
01110 = SYSCLK / 22
01111 = SYSCLK / 24
10000 = SYSCLK / 25
10001 = SYSCLK / 30
10010 = SYSCLK / 32
10011 = SYSCLK / 44
10100 = SYSCLK / 48
PD, Rev 4.0, September 2010
DESCRIPTION
DESCRIPTION
WM8918
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