Pre-Production
WM8904
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
MICBIAS Current Detect Threshold (AVDD = 1.8V)
000 = 0.070mA
Electret Condenser
Microphone
Interface
R6 (06h) Mic
Bias Control
0
6:4
MICDET_THR
[2:0]
000
001 = 0.260mA
010 = 0.450mA
011 = 0.640mA
100 = 0.830mA
101 = 1.020mA
110 = 1.210mA
111 = 1.400mA
Note that the value scales with AVDD. The value
quoted is correct for AVDD=1.8V.
MICBIAS Short Circuit Threshold (AVDD = 1.8V)
Electret Condenser
Microphone
Interface
3:2
MICSHORT_T
HR [1:0]
00
00 = 0.520mA
01 = 0.880mA
10 = 1.240mA
11 = 1.600mA
Note that the value scales with AVDD. The value
quoted is correct for AVDD=1.8V.
MICBIAS Current and Short Circuit Detect Enable
Electret Condenser
Microphone
Interface
1
0
MICDET_ENA
MICBIAS_ENA
0
0
0 = disabled
1 = enabled
MICBIAS Enable
0 = disabled
1 = enabled
Electret Condenser
Microphone
Interface
Register 06h Mic Bias Control 0
REGISTER
ADDRESS
BIT
LABEL
DEFAULT
DESCRIPTION
REFER TO
Selects MICBIAS voltage
000 = 9/10 x AVDD (1.6V)
001 = 10/9 x AVDD (2.0V)
010 = 7/6 x AVDD (2.1V)
011 = 4/3 x AVDD (2.4V)
100 to 111 = 3/2 x AVDD (2.7V)
Electret
R7 (07h) Mic
Bias Control
1
2:0
MICBIAS_SEL
[2:0]
000
Condenser
Microphone
Interface
Note that the voltage scales with AVDD. The value
quoted in brackets is correct for AVDD=1.8V.
Register 07h Mic Bias Control 1
PP, Rev 3.3, September 2012
143
w
WOLFSON [ WOLFSON MICROELECTRONICS PLC ]
