WM8741
Production Data
Figure 23 Bi-phase DSD Mode Timing Diagram
SOFTWARE CONTROL MODE
Software control allows access to all features of the WM8741. Selection of control mode is achieved
by configuring the state of MODE/LRSEL (pin 24):
PIN
NAME
DESCRIPTION
24
MODE/
LRSEL
0 = Hardware control mode
1 = 3-wire serial control mode
Z = 2-wire serial control mode
Table 14 Control Mode Configuration
DSD AND PCM MODE SWITCHING
The audio interface mode can be switched between DSD and PCM by writing MODESEL[1:0] in R7.
It is recommended that the chip is forced into a MUTE state before dynamically switching modes.
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
DSD/PCM mode select :
00 = PCM mode
R7
Mode Control 1
07h
[1:0] MODESEL
00
01 = Direct DSD Operation
10 = DSD plus mode
11 = Unused
Table 15 PCM/DSD Software Mode Selection
PCM DIGITAL AUDIO INTERFACE CONTROL REGISTERS
The PCM digital audio input format is configured by register bits FMT [1:0] and IWL[1:0]:
REGISTER ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
R5
Format Control
05h
1:0
IWL[1:0]
10
Audio interface input word length
select
00 = 16-bit
01 = 20-bit
10 = 24-bit
11 = 32-bit
3:2 FMT[1:0]
10
Audio interface input format select
00 = Right justified
01 = Left justified
10 = I2S
11 = DSP
Table 16 Interface Format Controls
Note:
1. In all modes, the data is signed 2's complement. The WM8741 digital filters always
input 24-bit data. If the interface is programmed into 32 bits, dither is applied according
to Table 37 before truncation to the internal wordlength.
PD, Rev 4.2, October 2009
28
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
