WM8985_07 WOLFSON [Wolfson Microelectronics plc], WM8985_07 Datasheet - Page 74

• Manufacturer Part Number: WM8985_07
• Description: Multimedia CODEC With Class D Headphone and Line Out
• Manufacturer: WOLFSON [Wolfson Microelectronics plc]

WM8985
DIGITAL AUDIO INTERFACES
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The audio interface has four pins:
The clock signals BCLK, and LRC can be outputs when the WM8985 operates as a master, or inputs
when it is a slave (see Master and Slave Mode Operation, below).
Five different audio data formats are supported:
All of these modes are MSB first. They are described in Audio Data Formats, below. Refer to the
Electrical Characteristic section for timing information.
MASTER AND SLAVE MODE OPERATION
The WM8985 audio interface may be configured as either master or slave. As a master interface
device the WM8985 generates BCLK and LRC and thus controls sequencing of the data transfer on
ADCDAT and DACDAT. To set the device to master mode register bit MS should be set high. In
slave mode (MS=0), the WM8985 responds with data to clocks it receives over the digital audio
interfaces.
AUDIO DATA FORMATS
In Left Justified mode, the MSB is available on the first rising edge of BCLK following an LRC
transition. The other bits up to the LSB are then transmitted in order. Depending on word length,
BCLK frequency and sample rate, there may be unused BCLK cycles before each LRC transition.
Figure 31 Left Justified Audio Interface (assuming n-bit word length)
In Right Justified mode, the LSB is available on the last rising edge of BCLK before a LRC transition.
All other bits are transmitted before (MSB first). Depending on word length, BCLK frequency and
sample rate, there may be unused BCLK cycles after each LRC transition.
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ADCDAT: ADC data output
DACDAT: DAC data input
LRC: Data Left/Right alignment clock
BCLK: Bit clock, for synchronisation
Left justified
Right justified
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DSP mode A
DSP mode B
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PP, Rev 3.5, March 2007
Pre-Production
74