WM8804 datasheet(14/66 Pages) WOLFSON

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WM8804

Production Data

PD Rev 4.1 September 2007

CONTROL INTERFACE OPERATION

Control of the WM8804 is implemented in either hardware control mode or software control mode.

The method of control is determined by sampling the state of the SDIN/HWMODE pin at power up or

at a hardware reset. If SDIN/HWMODE is low during power up the device is configured in hardware

control mode, otherwise the device is configured in software control mode.

SDIN/HWMODE

Hardware mode

Software mode

Table 8 Hardware or Software Mode Select

Software control is achieved using a 3-wire (3-wire write, 4-wire read) or a 2-wire serial interface.

The serial interface format is configured by sampling the state of the GPO0/SWIFMODE pin on

power up or at a hardware reset. If the GPO0/SWIFMODE pin is low the interface is configured in 2-

wire mode, otherwise the interface is configured in 3-wire SPI compatible mode.

GPO0/SWIFMODE

2-wire interface

3-wire interface

Table 9 Software Mode Control Interface Select

3-WIRE (SPI COMPATIBLE) SERIAL CONTROL MODE – REGISTER WRITE

SDIN is used for the program data, SCLK is used to clock in the program data and CSB is used to

latch in the program data. SDIN is sampled on the rising edge of SCLK. The 3-wire interface write

protocol is shown in Figure 8.

Figure 8 3-Wire Serial Interface Register Write Protocol

•

W is a control bit indicating a read or write operation. 0 =write operation, 1 = read operation

•

REGA[6:0] is the register address.

•

DIN[7:0] is the data to be written to the register being addressed.

•

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

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