WM8775

Production Data

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PD Rev 4.1, June 2006

20

Figure 19 DSP/PCM Mode Audio Interface (mode B, LRP=0, Slave)

CONTROL INTERFACE OPERATION

The WM8775 is controlled using a 3-wire serial interface in a SPI compatible configuration or

a 2-wire serial interface mode. The interface type is selected by the MODE pin as shown in

Table 9.

MODE

Control Mode

0

2 wire interface

1

3 wire interface

Table 9 Control Interface Selection via MODE pin

3-WIRE (SPI COMPATIBLE) SERIAL CONTROL MODE

DI is used for the program data, CL is used to clock in the program data and CE is used to latch the

program data. DI is sampled on the rising edge of CL. The 3-wire interface protocol is shown in

Figure 20.

Figure 20 3-Wire SPI Compatible Interface

1.

B[15:9] are Control Address Bits

2.

B[8:0] are Control Data Bits

3.

CE is edge sensitive – the data is latched on the rising edge of CE.

B15

B14

B13

B12

B11

B10

B9

B8

B7

B6

B5

B4

B3

B2

B1

B0

CE

CL

DI