WM8737L
Production Data
DESCRIPTION
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
4
LRP
0
Right, left & I2S modes – ADCLRC
polarity
1 = invert ADCLRC polarity
0 = normal ADCLRC polarity
DSP Mode – mode A/B select
1 = MSB is available on 1st BCLK
rising edge after ADCLRC rising edge
(mode B)
0 = MSB is available on 2nd BCLK
rising edge after ADCLRC rising edge
(mode A)
6
7
MS
0
0
Master / Slave Mode Control
1: Master Mode
0: Slave Mode
SDODIS
ADCDAT serial data pin disable
0: ADCDAT pin enabled
1: ADCDAT pin off (high impedance)
Table 14 Audio Data Format Control
Note: Right Justified mode does not support 32-bit data. If WL=11 in Right justified mode, the actual
word length is 24 bits.
To prevent any communication problems on the Audio Interface, the interface is disabled (ADCDAT
tristated and floating) when the WM8737L starts up. Once the Audio Interface and sample rates have
been programmed, the audio interface can be activated under software control by setting the AI bit
(see “Power Management” section).
MASTER CLOCK AND AUDIO SAMPLE RATES
The master clock (MCLK) is used to operate the digital filters and the noise shaping circuits. The
WM8737L supports a wide range of master clock frequencies, and can generate many commonly
used audio sample rates directly from the master clock.
There are two clocking modes:
‘Normal’ mode supports master clocks of 128fs, 192fs, 256fs, 384fs, and their multiples
USB mode supports 12MHz or 24MHz master clocks. This mode is intended for use in
systems with a USB interface, and eliminates the need for an external PLL to generate
another clock frequency for the audio ADC.
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R8 (08h)
6
0
CLKDIV2
0
0
Master Clock Divide by 2
1: MCLK is divided by 2
0: MCLK is not divided
Clocking Mode Select
1: USB Mode
Clocking and
Sample Rate
Control
USB
0: ‘Normal’ Mode
5:1
7
SR[4:0]
0000
0
Sample Rate Control
Clock Ratio Autodetect
(Slave Mode Only)
0: Autodetect Off
AUTO
DETECT
1: Autodetect On
Table 15 Clocking and Sample Rate Control
PD, Rev 4.4, January 2012
28
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
