WM8716
Production Data
AUDIO DATA INTERFACE
Data may be input at a rate corresponding to the system clock having a rate of 256fs or 384fs or
512fs or 768fs, in which case an oversampling ratio of 128x is selected. Alternatively a rate of 128fs
or 192fs may be used, in which case the first filter stage is bypassed and an oversampling ratio of
64x results. Finally, in MODE8X, data may be input at 8x the normal rate, in which case separate
input pins are used to input the two stereo channels of data (unless DIFFHW mode and MODE8X
are both selected, in which case only a mono channel is converted differentially). In MODE8X all filter
stages are by-passed, prior to the sigma delta modulator. Data is input MSB first in all modes.
NORMAL SAMPLE RATE
In normal mode, the data is input serially on one pin for both left and right channels.
Data can be “right justified” meaning that the last 16, 20 or 24 bits (depending on chosen PCM word
length) that were clocked in prior to the transition on LRCIN are valid.
Alternatively data can be “left justified” (20 and 24-bit PCM data only), where the bits are clocked in
as the first 20 or 24 bits after a transition on LRCIN.
For the three I2S modes supported (16-bit, 20-bit and 24-bit PCM data), data is clocked “left justified”
except with one additional preceding clock cycle.
1/fs
LEFT
RIGHT
LRCIN (PIN 1)
BCKIN (PIN 3)
16-BIT RIGHT
JUSTIFIED
DIN (PIN 2)
B2 B1 B0
B2 B1 B0
B2 B1 B0
B0
B15
B2 B1 B0
B2 B1 B0
B2 B1 B0
B15
B2 B1 B0
B2 B1 B0
B2 B1 B0
20-BIT RIGHT
JUSTIFIED
DIN (PIN 2)
B19 B18 B17
B19 B18 B17
24-BIT RIGHT
JUSTIFIED
DIN (PIN 2)
B23 B22 B21 B20 B19
B23 B22 B21 B20 B19
24-BIT LEFT
JUSTIFIED
DIN (PIN 2)
B23 B22 B21
B4 B3 B2 B1 B0
B23 B22 B21
B4 B3 B2 B1 B0
20-BIT LEFT
JUSTIFIED
DIN (PIN 2)
B0
B19 B18 B17
B0
B19 B18 B17
B0
LEFT
RIGHT
LRCIN (PIN 1)
BCKIN (PIN 3)
16-BIT I2S
DIN (PIN 2)
B15
B23
B19
B2 B1 B0
B15
B23
B19
B2 B1 B0
B15
B23
B19
24-BIT I2S
DIN (PIN 2)
B6 B5 B4 B3 B2 B1 B0
B6 B5 B4 B3 B2 B1 B0
20-BIT I2S
B2 B1 B0
B2 B1 B0
DIN (PIN 2)
Figure 4 Audio Data Input Format
WOLFSON MICROELECTRONICS LTD
PD Rev 3.1 April 2001
8
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
