wm8918 Wolfson Microelectronics plc, wm8918 Datasheet - Page 119

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

Production Data
w
0 (00h)
1 (01h)
2 (02h)
3 (03h)
4 (04h)
5 (05h)
6 (06h)
7 (07h)
WSEQ
INDEX
REGISTER
ADDRESS
R14 (0Eh)
R15 (0Fh)
R22 (16h)
R18 (12h)
R4 (04h)
R5 (05h)
R5 (05h)
R4 (04h)
WIDTH
5 bits
8 bits
2 bits
2 bits
2 bits
2 bits
1 bit
1 bit
DEFAULT SEQUENCES
When the WM8918 is powered up, two Control Write Sequences are available through default
settings in both RAM and ROM memory locations. The purpose of these sequences, and the register
write required to initiate them, is summarised in Table 80. In both cases, a single register write will
initiate the sequence.
Table 80 Write Sequencer Default Sequences
Note on Shutdown sequence: The instruction at Index Address 25 (19h) shorts the outputs
LINEOUTL and LINEOUTR. If the Line outputs are not in use at the time the sequence is run, then
the sequence could, instead, be started at Index Address 26.
Index addresses 0 to 31 may be programmed to users’ own settings at any time, as described in
“Programming a Sequence”. Users’ own settings remain in memory and are not affected by software
resets (i.e. writing to Register R0). However, any non-default sequences are lost when the device is
powered down.
START-UP SEQUENCE
The Start-up sequence is initiated by writing 0100h to Register R111 (6Fh). This single operation
starts the Control Write Sequencer at Index Address 0 (00h) and executes the sequence defined in
Table 81.
For typical clocking configurations with MCLK=12.288MHz, this sequence takes approximately
300ms to run.
Note that, for fast startup, step 18 may be overwritten with dummy data in order to achieve startup
within 50ms (see “Quick Start-Up and Shutdown”).
WSEQ START
25 (19h)
0 (00h)
INDEX
START
Bit 0
Bit 0
Bit 1
Bit 0
Bit 0
Bit 0
Bit 1
Bit 2
WSEQ FINISH
DATA
1Ah
47h
01h
01h
03h
03h
01h
03h
22 (16h)
39 (27h)
INDEX
DELAY
0h
6h
0h
0h
0h
0h
0h
5h
Shutdown sequence
Start-Up sequence
EOS
0b
0b
0b
0b
0b
0b
0b
0b
PURPOSE
BIAS_ENA = 0
(delay = 0.5625ms)
VMID_BUF_ENA = 1
VMID_RES[1:0] = 11b
VMID_ENA = 1
(delay = 4.5ms)
VMID_RES[1:0] = 01b
(delay = 0.5625ms)
BIAS_ENA = 1
(delay = 0.5625ms)
HPL_PGA_ENA = 1
HPR_PGA_ENA = 1
(delay = 0.5625ms)
LINEOUTL_PGA_ENA = 1
LINEOUTR_PGA_ENA = 1
(delay = 0.5625ms)
CLK_DSP_ENA = 1
(delay = 0.5625ms)
DACL_ENA = 1
DESCRIPTION
PD, Rev 4.0, September 2010
Register R111 (6Fh)
Register R111 (6Fh)
Write 0100h to
Write 0119h to
TO INITIATE
WM8918
119