WM9713L datasheet(103/108 Pages) WOLFSON

103 / 108 page

Pre-Production

WM9713L

PP Rev 3.0 June 2006

103

JACK INSERT DETECTION

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 41 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.

HOOKSWITCH DETECTION

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 42 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.

WM9713L Datasheet(PDF) 103 Page - Wolfson Microelectronics plc