wm9714l Wolfson Microelectronics plc, wm9714l Datasheet - Page 48

• Manufacturer Part Number: wm9714l
• Description: Ac?97 Audio Codec
• Manufacturer: Wolfson Microelectronics plc

WM9714L
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MICBIAS CURRENT DETECT
The WM9714L includes a microphone bias current detect circuit with programmable thresholds for
the microphone bias current, above which an interrupt will be triggered. There are two separate
interrupt bits, MICDET to e.g. distinguish between one or two microphones connected to the
WM9714L, and MICSHT to detect a shorted microphone (mic button press). The microphone current
detect threshold is set by MCDTHR[2:0], for MICDET, and MCDSCTHR[1:0] for MICSHT.
Thresholds for each code are shown in Table 25
When not in use the microphone bias current detect circuit can be powered down using the
Powerdown register bit MCD (register 3Eh, bit 15).
See the GPIO and Interrupt Controller sections for details on the interrupt and status readback for
these MICBIAS current detection features.
Table 25 Microphone Current Detect Control
22h
REGISTER
ADDRESS
4:2
1:0
BIT
MCDTHR
MCDSCTR
LABEL
000
00
DEFAULT
Mic Detect Threshold Control
000 = 100µA
… (100µA steps)
111 = 800µA
Note: These values are for 3.3V supply and
scale with supply voltage (AVDD).
Mic Detect Short Circuit Threshold
Control
00 = 600µA
01 = 1200uA
10 = 1800uA
11 = 2400µA
Note: These values are for 3.3V supply and
scale with supply voltage (AVDD).
DESCRIPTION
PP, Rev 3.2, October 2008
Pre-Production
48