WM8718

Production Data

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PD Rev 4.3 November 2006

15

The WM8718 will automatically detect when data with a LRCIN period of exactly 32 BCKINs is

sent, and select 16-bit mode - overriding any previously programmed word length. Word length

will revert to a programmed value only if a LRCIN period other than 32 BCKINs is detected.

In DSP Mode A or DSP Mode B, the data is time multiplexed onto DIN. LRCIN is used as a

frame sync signal to identify the MSB of the first word. The minimum number of BCKINs per

LRCIN period is 2 times the selected word length. Any mark to space ratio is acceptable on

LRCIN provided the rising edge is correctly positioned. (See Figure 10 and Figure 11)

LEFT JUSTIFIED MODE

In left justified mode, the MSB is sampled on the first rising edge of BCKIN following a LRCIN

transition. LRCIN is high during the left data word and low during the right data word.

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 7 Left Justified Mode Timing Diagram

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 data word and low during the right data word.

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 8 Right Justified Mode Timing Diagram

I

In I

transition. LRCIN is low during the left data word and high during the right data word.

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 9 I