WM8951L_07 WOLFSON [Wolfson Microelectronics plc], WM8951L_07 Datasheet - Page 25

• Manufacturer Part Number: WM8951L_07
• Description: Stereo ADC with Microphone Input and Clock Generator
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

Production Data
AUDIO DATA SAMPLING RATES
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Figure 21 Master Mode
As a slave device the WM8951L sequences the data transfer (ADCDAT) over the digital audio
interface in response to the external applied clocks (BCLK, ADCLRC). This is illustrated in Figure 22.
Figure 22 Slave Mode
Note that the WM8951L relies on controlled phase relationships between audio interface BCLK, and
the master MCLK or CLKOUT. To avoid any timing hazards, refer to the timing section for detailed
information.
The WM8951L provides for two modes of operation (normal and USB) to generate the required ADC
sampling rates. Normal and USB modes are programmed under software control according to the
table below.
In Normal mode, the user controls the sample rate by using an appropriate MCLK or crystal
frequency and the sample rate control register setting. The WM8951L can support sample rates from
8ks/s up to 96ks/s.
In USB mode, the user must use a fixed MLCK or crystal frequency of 12MHz to generate sample
rates from 8ks/s to 96ks/s. It is called USB mode since the common USB (Universal Serial Bus)
clock is at 12MHz and the WM8951L can be directly used within such systems. WM8951L can
generate all the normal audio sample rates from this one Master Clock frequency, removing the need
for different master clocks or PLL circuits.
WM8951
ADC
WM8951
ADC
ADCLRC
ADCDAT
ADCLRC
ADCDAT
BCLK
BCLK
ENCODER/
DECODER
ENCODER/
DECODER
DSP
DSP
PD Rev 4.1 December 2007
WM8951
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