WM8726
Production Data
1/fs
LEFT CHANNEL
RIGHT CHANNEL
LRCIN
BCKIN
1 BCKIN
1 BCKIN
DIN
1
2
3
n
1
2
3
n
n-2 n-1
n-2 n-1
LSB
LSB
MSB
MSB
Figure 3 I2S Mode Timing Diagram
RIGHT JUSTIFIED MODE
The WM8726 supports word lengths of 16-bits in right justified mode.
In right justified mode, the digital audio interface receives data on the DIN input. Audio Data is
time multiplexed with LRCIN indicating whether the left or right channel is present. LRCIN is also
used as a timing reference to indicate the beginning or end of the data words.
In right justified mode, the minimum number of BCKINs per LRCIN period is 2 times the selected
word length. LRCIN must be high for a minimum of word length BCKINs and low for a minimum of
word length BCKINs. Any mark to space ratio on LRCIN is acceptable provided the above
requirements are met.
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.
1/fs
LEFT CHANNEL
RIGHT CHANNEL
LRCIN
BCKIN
DIN
1
2
3
1
2
3
14 15
14 15
16
16
MSB
LSB
MSB
LSB
Figure 4 Right Justified Mode Timing Diagram
DSP MODE
A DSP compatible, time division multiplexed format is also supported by the WM8726. This
format is of the type where a ‘synch’ pulse is followed by two data words (left and right) of
predetermined word length. (16-bits). The ‘synch’ pulse replaces the normal duration LRCIN, and
DSP mode is auto-detected by the shorter than normal duration of the LRCIN. If LRCIN is of 4
BCKIN or less duration, the DSP compatible format is selected. Mode A and Mode B clock
formats are supported, selected by the state of the FORMAT pin.
PD Rev 4.1 September 2005
11
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
