WM9082 WOLFSON [Wolfson Microelectronics plc], WM9082 Datasheet - Page 10

• Manufacturer Part Number: WM9082
• Description: PDM Input Mono 3W Class D Speaker Driver
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM9082
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DEVICE CONTROL CODES
The channel selection for the WM9082 speaker driver is implemented automatically by sensing which
of the inputs pins is CLK and which pin is DATA, as defined in Table 1.
To ensure correct channel selection, it must be ensured that the DATA input is disabled whenever the
CLK input is disabled. If the DATA input signal is present when CLK is disabled, this may result in
incorrect channel selection.
Table 1 PDM Channel Selection
If stereo operation is required, using two WM9082 speaker drivers, then this can be implemented very
easily, by cross-connecting the CLK and DATA wires on the two speaker drivers, as illustrated in
Figure 2.
Figure 2 Stereo PDM Operation
The channel detection is determined automatically at device start-up, and also after any period when
the CLK input has stopped.
When power supplies are present (see “Recommended Operating Conditions”), and audio data is
input at the audio interface, the WM9082 powers up and the Class D speaker driver is enabled. The
WM9082 selects either the Left or Right channel data as described in “PDM Audio Interface”.
The WM9082 can be controlled using specific data sequences, known as Control Codes, received
over the PDM audio interface. Each Control Code is a “zero” code when decoded as audio data.
Therefore, the Control Codes can be transmitted to the WM9082 in the form of silent audio data, but
the codes will be recognised by the WM9082 as control instructions.
The WM9082 Control Codes are defined in Table 2 and Table 3.
The Control Codes are 8-bit codes, which must be transmitted LSB first.
The Page 1 Control Codes (see Table 2) are valid when transmitted consecutively for the required
number of times. The Page 2 Control Codes (see Table 3) are valid only when preceded by the “Page
2 access” instruction (ie. Page 1, Code 6).
In most cases, the Control Codes are only valid if they are received more than 32 times consecutively
(see below for further details). For greatest reliability, however, it is recommended that the host device
always transmits Control Codes at least 64 times whenever it is desired to send a control instruction
to the WM9082.
If the WM9082 is configured to receive Left channel data, then it will only respond to Control Codes
received on the Left channel of the PDM interface. Similarly, if the WM9082 is configured to receive
Right channel data, then it will only respond to Control Codes received on the Right channel.
CLK = IN1
CLK = IN2
INPUT CONFIGURATION
DATA = IN2
DATA = IN1
SPEAKER CHANNEL
Right
Left
PD, August 2012, Rev 4.1
Production Data
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