WM8729

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WOLFSON MICROELECTRONICS LTD

PP Rev 1.2 April 2001

8

RIGHT JUSTIFIED MODE

In right justified mode, the LSB is sampled on the rising edge of BCKIN preceding a LRCIN

transition. LRCIN is high during the left samples and low during the right samples.

LEFT CHANNEL

RIGHT CHANNEL

LRCIN

BCKIN

DIN

1/fs

n

3

2

1

n-2 n-1

LSB

MSB

n

3

2

1

n-2 n-1

LSB

MSB

Figure 3 Right Justified Mode Timing Diagram

I

In I

transition. LRCIN is low during the left samples and high during the right samples.

LEFT CHANNEL

RIGHT CHANNEL

LRCIN

BCKIN

DIN

1/fs

n

3

2

1

n-2 n-1

LSB

MSB

n

3

2

1

n-2 n-1

LSB

MSB

1 BCKIN

1 BCKIN

Figure 4 I

AUDIO DATA SAMPLING RATES

The master clock for WM8729 supports audio sampling rates from 128fs to 768fs, where fs is the

audio sampling frequency (LRCIN) typically 32kHz, 44.1kHz, 48kHz, 96kHz or 192kHz. The

master clock is used to operate the digital filters and the noise shaping circuits.

The WM8729 has a master clock detection circuit that automatically determines the relation

between the master clock frequency and the sampling rate (to within +/- 8 master clocks). If there

is a greater than 8 clocks error, the interface shuts down the DAC and mutes the output. The

master clock should be synchronised with LRCIN, although the WM8729 is tolerant of phase

differences or jitter on this clock.

MASTER CLOCK FREQUENCY (MHZ) (MCLK)

SAMPLING

RATE

(LRCIN)

128fs

192fs

256fs

384fs

512fs

768fs

32kHz

4.096

6.144

8.192

12.288

16.384

24.576

44.1kHz

5.6448

8.467

11.2896

16.9340

22.5792

33.8688

48kHz

6.114

9.216

12.288

18.432

24.576

36.864

96kHz

12.288

18.432

24.576

36.864

Unavailable

Unavailable

192kHz

24.576

36.864

Unavailable

Unavailable

Unavailable

Unavailable

Table 1 Master Clock Frequencies Versus Sampling Rate