WM8904
Pre-Production
Note that, if power is removed from the WM8904 or if a software reset is performed, then the default
sequence will be restored, and the DC offset correction will be necessary on the output paths once
more.
REGISTER
ADDRESS
VALUE
DESCRIPTION
R108 (6Ch)
WSEQ_ENA = 1
0111h
Write Sequencer 0
WSEQ_WRITE_INDEX = 11h
This enables the Write Sequencer and selects WSEQ
Index 17 (11h) for modification
R109 (6Dh)
WSEQ_DATA_WIDTH = 000
WSEQ_DATA_START = 0000
WSEQ_ADDR = FFh
00FFh
0000h
0100h
0000h
Write Sequencer 1
This modifies WSEQ Index 17 (11h) with Dummy step
WSEQ_EOS = 0
R110 (6Eh)
Write Sequencer 2
WSEQ_DELAY = 0000
WSEQ_DATA = 00h
This modifies WSEQ Index 17 (11h) with Dummy step
WSEQ_ABORT = 0
R111 (6Fh)
Write Sequencer 3
WSEQ_START = 1
WSEQ_START_INDEX = 00h
This starts the Write Sequencer at Index address 0 (00h)
DAC_MONO = 0
R33 (21h)
DAC Digital 1
DAC_SB_FILT = 0
DAC_MUTERATE = 0
DAC_UNMUTE_RAMP = 0
DAC_OSR128 = 0
DAC_MUTE = 0
DEEMPH = 00
This un-mutes the DACs
Table 92 Fast Start-up from Standby Control
The WSEQ_BUSY bit (in Register R112, see Table 85) will be set to 1 while the sequence runs.
When this bit returns to 0, the device has been set up and is ready for DAC playback operation.
QUICK SHUTDOWN (DEFAULT SEQUENCE)
The default shutdown sequence assumes the initial device conditions are as configured by the default
start-up sequence. Assuming 12.288MHz input clock, the shutdown sequence will take approximately
350ms to complete.
The following register operation will initiate the default shutdown sequence.
REGISTER
VALUE
DESCRIPTION
ADDRESS
R111 (6Fh)
Write Sequencer 3
WSEQ_ABORT = 0
WSEQ_START = 1
0119h
WSEQ_START_INDEX = 19h
This starts the Write Sequencer at Index address 25 (19h)
Table 93 Quick Shutdown Control
The WSEQ_BUSY bit (in Register R112, see Table 85) will be set to 1 while the sequence runs.
When this bit returns to 0, the system clock can be disabled (CLK_SYS_ENA=0) and MCLK can be
stopped.
PP, Rev 3.3, September 2012
136
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WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
