wm9713 Wolfson Microelectronics plc, wm9713 Datasheet - Page 127

• Manufacturer Part Number: wm9713
• Description: Ac?97 Audio + Touchpanel Codec
• Manufacturer: Wolfson Microelectronics plc

Pre-Production
JACK INSERT DETECTION
HOOKSWITCH DETECTION
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The circuit diagram below shows how to detect when a headphone or headset has been plugged into
the headphone socket. It generates an interrupt, instructing the controller to enable HPL and HPR
and disable OUT3.
Figure 43 Jack Insert Detection Circuit
The circuit requires a headphone socket with a switch that closes on insertion (for using sockets with
a switch that opens on insertion, please refer to Application Note WAN0182). It detects both
headphones and phone headsets. Any GPIO pin can be used, provided that it is configured as an
input.
Alternatively a headphone socket with a switch that opens on insertion can be used. For this mode
of operation the GPIO input must be inverted.
The circuit diagram below shows how to detect when the “hookswitch” of a phone headset is pressed
(pressing the hookswitch is equivalent to lifting the receiver in a stationary telephone).
Figure 44 Hookswitch Detection Circuit
The circuit uses a GPIO pin as a sense input. The impedance of the microphone and the resistor in
the MICBIAS path must be such that the potential at the GPIO pin is above 0.7×DBVDD when the
hookswitch is open, and below 0.3×DBVDD when it is closed.
PP Rev 3.2 September 2008
WM9713L
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