WM8903LGEFK/RV Wolfson Microelectronics, WM8903LGEFK/RV Datasheet - Page 174

• Manufacturer Part Number: WM8903LGEFK/RV
• Description: Audio CODECs ULTRA LOW PWR HI FI CODEC
• Manufacturer: Wolfson Microelectronics

Specifications of WM8903LGEFK/RV

• Audio Codec Type: Stereo Codec
• No. Of Adcs: 2
• No. Of Dacs: 2
• No. Of Input Channels: 6
• No. Of Output Channels: 8
• Adc / Dac Resolution: 24bit
• Sampling Rate: 96kHz
• Operating Temperature Range: -40°C To +85°C
• Rohs Compliant: Yes
• Adcs / Dacs Signal To Noise Ratio: 96dB
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

WM8903
MIC DETECTION SEQUENCE USING MICBIAS CURRENT
Figure 68 Mic Insert and Hook Switch Detect: Example MICBIAS Current Plot
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This section details an example sequence which summarises how the host processor can configure
and detect the events supported by the MICBIAS current detect function (see “Electret Condenser
Microphone Interface”):
Figure 68 shows an example of how the MICBIAS current flow varies versus time, during mic
insertion and hook switch events. The Y axis is annotated with the Mic detection thresholds, and the
X axis is annotated with the stages of an example sequence as detailed in Table 86, to illustrate how
the host processor can implement mic insertion and hook switch detection.
The sequence assumes that the microphone insertion and hook switch detection functions are
monitored by polling the interrupt flags using the control interface. Note that the maximum
mechanical bounce times for mic insertion and removal must be fully understood by the software
programmer.
A GPIO pin could be used as an alternative mechanism to monitor the MICBIAS detection functions.
This enables the host processor to detect mechanical bounce at any time.
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Mic insertion/removal
Hook switch press/release
PD, Rev 4.0, September 2010
Production Data
174