WM8951L_07 Datasheet, PDF (26/42 Pages) Wolfson Microelectronics plc – Stereo ADC with Microphone Input and Clock Generator

WM8951L
Production Data
Sample rates listed in the following sections are supported.
REGISTER
ADDRESS
0001000
Sampling
Control
BIT
LABEL
0
USB/
NORMAL
1
BOSR
5:2 SR[3:0]
Table 11 Sample Rate Control
DEFAULT
DESCRIPTION
0
0
0000
Mode Select
1 = USB mode (250/272fs)
0 = Normal mode (256/384fs)
Base Over-Sampling Rate
USB Mode
0 = 250fs
1 = 272fs
Normal Mode
96/88.2kHz
0 = 256fs
1 = 128fs
1 = 384fs
1 = 192fs
Sample rate control;
See USB Mode and Normal Mode
Sample Rate sections for operation
NORMAL MODE SAMPLE RATES
In normal mode MCLK/crystal oscillator is set up according to the desired sample rates of the ADC.
For ADC sampling rates of 8, 32, 48 or 96kHz, MCLK frequencies of either 12.288MHz (256fs) or
18.432MHz (384fs) can be used. For ADC sampling rates of 8, 44.1 or 88.2kHz from MCLK
frequencies of either 11.2896MHz (256fs) or 16.9344MHz (384fs) can be used.
Table 12 should be used to set up the device to work with the various sample rate combinations. For
example if the user wishes to use the WM8951L in normal mode with the ADC sample rate at 48kHz
then the device should be programmed with BOSR = 0, SR3 = 0, SR2 = 0, SR1 = 0 and SR0 = 0 with
a 12.288MHz MCLK or with BOSR = 1, SR3 = 0, SR2 = 0, SR1 = 0 and SR0 = 0 with a 18.432MHz
MCLK. The ADC will then operate with a Digital Filter of type 1, refer to Digital Filter Characteristics
section for an explanation of the different filter types.
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PD Rev 4.1 December 2007
26