wm8918 Wolfson Microelectronics plc, wm8918 Datasheet - Page 126

• Manufacturer Part Number: wm8918
• Description: Ultra Low Power Dac For Portable Audio Applications
• Manufacturer: Wolfson Microelectronics plc

WM8918
w
Note that, if power is removed from the WM8918 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.
Table 85 Fast Start-up from Standby Control
The WSEQ_BUSY bit (in Register R112, see Table 78) 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.
Table 86 Quick Shutdown Control
The WSEQ_BUSY bit (in Register R112, see Table 78) 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.
R108 (6Ch)
Write Sequencer 0
R109 (6Dh)
Write Sequencer 1
R110 (6Eh)
Write Sequencer 2
R111 (6Fh)
Write Sequencer 3
R33 (21h)
DAC Digital 1
R111 (6Fh)
Write Sequencer 3
REGISTER
REGISTER
ADDRESS
ADDRESS
VALUE
VALUE
0111h
00FFh
0000h
0100h
0000h
0119h
WSEQ_ENA = 1
WSEQ_WRITE_INDEX = 11h
This enables the Write Sequencer and selects WSEQ
Index 17 (11h) for modification
WSEQ_DATA_WIDTH = 000
WSEQ_DATA_START = 0000
WSEQ_ADDR = FFh
This modifies WSEQ Index 17 (11h) with Dummy step
WSEQ_EOS = 0
WSEQ_DELAY = 0000
WSEQ_DATA = 00h
This modifies WSEQ Index 17 (11h) with Dummy step
WSEQ_ABORT = 0
WSEQ_START = 1
WSEQ_START_INDEX = 00h
This starts the Write Sequencer at Index address 0 (00h)
DAC_MONO = 0
DAC_SB_FILT = 0
DAC_MUTERATE = 0
DAC_UNMUTE_RAMP = 0
DAC_OSR128 = 0
DAC_MUTE = 0
DEEMPH = 00
This un-mutes the DACs
WSEQ_ABORT = 0
WSEQ_START = 1
WSEQ_START_INDEX = 19h
This starts the Write Sequencer at Index address 25 (19h)
DESCRIPTION
DESCRIPTION
PD, Rev 4.0, September 2010
Production Data
126