WM8994 Datasheet, PDF (271/359 Pages) Wolfson Microelectronics plc – Multi-Channel Audio Hub CODEC for Smartphones

Production Data
Register 36h Speaker Mixer
WM8994
REGISTER BIT
LABEL
DEFAULT
DESCRIPTION
ADDRESS
R55 (37h)
7 LINEOUT1_FB
0
Enable ground loop noise feedback on LINEOUT1
Additional
Control
0 = Disabled
1 = Enabled
6 LINEOUT2_FB
0
Enable ground loop noise feedback on LINEOUT2
0 = Disabled
1 = Enabled
0
VROI
0
Buffered VMID to Analogue Line Output Resistance
(Disabled Outputs)
0 = 20k from buffered VMID to output
1 = 500 from buffered VMID to output
Register 37h Additional Control
REFER TO
REGISTER BIT
LABEL
DEFAULT
DESCRIPTION
ADDRESS
R56 (38h)
7 LINEOUT_VMI
AntiPOP (1)
D_BUF_ENA
0
Enables VMID reference for line outputs in single-
ended mode
0 = Disabled
1 = Enabled
6 HPOUT2_IN_E
0
HPOUT2MIX Mixer and Input Stage Enable
NA
0 = Disabled
1 = Enabled
5 LINEOUT1_DI
SCH
0
Discharges LINEOUT1P and LINEOUT1N outputs
0 = Not active
1 = Actively discharging LINEOUT1P and LINEOUT1N
4 LINEOUT2_DI
SCH
0
Discharges LINEOUT2P and LINEOUT2N outputs
0 = Not active
1 = Actively discharging LINEOUT2P and LINEOUT2N
Register 38h AntiPOP (1)
REFER TO
REGISTER BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
ADDRESS
R57 (39h)
8 MICB2_DISCH
0
Microphone Bias 2 Discharge
AntiPOP (2)
0 = MICBIAS2 floating when disabled
1 = MICBIAS2 discharged when disabled
7 MICB1_DISCH
0
Microphone Bias 1 Discharge
0 = MICBIAS1 floating when disabled
1 = MICBIAS1 discharged when disabled
6:5 VMID_RAMP
[1:0]
00
VMID soft start enable / slew rate control
00 = Normal slow start
01 = Normal fast start
10 = Soft slow start
11 = Soft fast start
If VMID_RAMP = 1X is selected for VMID start-up or
shut-down, then the soft-start circuit must be reset by
setting VMID_RAMP=00 after VMID is disabled, before
VMID is re-enabled. VMID is disabled / enabled using
the VMID_SEL register.
3 VMID_BUF_EN
0
VMID Buffer Enable
A
0 = Disabled
w
PD, April 2012, Rev 4.4
271