WM8740
Production Data
DE-EMPHASIS CONTROL
MDDM1
MCDMO
DE-EMPHASIS
PIN 27
PIN 26
L
L
L
H
L
Off
48kHz
44.1kHz
32kHz
H
H
H
Table 2 De-Emphasis Control
AUDIO INPUT FORMAT
ML/I2S
PIN 28
L
CSBIWO
PIN 23
L
DATA FORMAT
16 bit normal right
justified
L
H
20 bit normal right
justified
H
H
L
16 bit I2S
24 bit I2S
H
Table 3 Audio Input Format
SOFT MUTE
MUTEB
PIN 25
L
FUNCTION
Mute On (no output)
Mute Off (normal operation)
H
Table 4 Soft Mute
A logic low on the MUTEB pin will cause the attenuation to ramp to infinite attenuation at a rate of
128/fs seconds per 0.5dB step. Setting MUTEB high will cause the attenuation to ramp back to its
previous value.
SOFTWARE CONTROL INTERFACE
The WM8740 can be controlled using a 3-wire serial interface. MD/DM0 (pin 26) is used for the
program data, MC/DM1 (pin 22) is used to clock in the program data and ML/I2S (pin 28) is use to
latch in the program data. The 3-wire interface protocol is shown in Figure 6. CSB/IWO (pin 23) must
be low when writing.
ML/I2S (PIN 28)
MC/DM1 (PIN 27)
MD/DM0 (PIN 26)
B15 B14 B13
B2
B1
B0
Figure 6 Three-Wire Serial Interface
PD Rev 4.0 April 2004
12
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
