wm9713 Wolfson Microelectronics plc, wm9713 Datasheet - Page 27

• Manufacturer Part Number: wm9713
• Description: Ac?97 Audio + Touchpanel Codec
• Manufacturer: Wolfson Microelectronics plc

Pre-Production
PCM INTERFACE
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OPERATION
WM9713L can implement a PCM voice codec function using the dedicated VXDAC and either one or
both of the existing hi-fi ADC’s. In PCM codec mode, VXDAC input and ADC output are interfaced
via a PCM style port via GPIO pins.
This interface can support one ADC channel, or stereo/dual ADC channels if required, (two channels
of data are sent per PCM frame as back to back words).
In voice only mode, the AC link is used only for control information, not audio data. Therefore it will
generally be shut down (PR4=1), except when control data must be sent.
The PCM interface makes use of 4 of the GPIO interface pins, for clock, frame, and data in/out. If the
PCM codec function is not enabled then the GPIO pins may be used for other functions.
INTERFACE PROTOCOL
The WM9713L PCM audio interface is used for the input of data to the Voice DAC and the output of
data from the Stereo ADC. When enabled, the PCM audio interface uses four GPIO pins:
Depending on the mode of operation (see “PCM Interface Modes”), at least one of these four pins
must be set up as an output by writing to register 4Ch (see Table 62). When not enabled the GPIOs
may be used for other functions on the WM9713L.
PCM INTERFACE MODES
The WM9713L PCM audio interface may be configured in one of four modes:
PCM AUDIO DATA FORMATS
Four different audio data formats are supported:
All four of these modes are MSB first. They are described below. Refer to the Electrical
Characteristics section for timing information.
Note:
PCMCLK and PCMFS must be synchronized with the BITCLK from the AC’97 interface.
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GPIO1/PCMCLK: Bit clock
GPIO3/PCMFS: Frame Sync
GPIO4/PCMDAC: Voice DAC data input
GPIO5/PCMADC: Stereo ADC data output
Disabled Mode: The WM9713L disables and tri-states all PCM interface pins. Any
clock input is ignored and ADC/DAC data is not transferred.
Slave Mode: The WM9713L accepts PCMCLK and PCMFS as inputs from an
external source.
Master Mode: The WM9713L generates PCMCLK and PCMFS as outputs.
Partial Master Mode: The WM9713L generates PCMCLK as an output, and
accepts PCMFS as an external input.
DSP mode
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PP Rev 3.2 September 2008
WM9713L
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