Enabler II-G Assiste GPS Integration Guide - Farnell

Enfora Enabler III-G
Modem Integration Guide
6.6.27. Headset Detect (Pin 47)
Headset Plug/Unplug detection. This pin is used to automatically switch to the headset audio path when
enabled with AT$VSELECT=3. The device will default to handset when no Headset is detected.
• 2 modes:
Module already ON (Battery connected, VRIO ON) and plug event;
Module OFF and plug event: the plug detection will be effective once VRIO is set ON
• Plug and unplug detections are digitally debounced (debouncing time = 8 ms).
• The jack plug detection feature is addressed through the HSDET pin. The integrated pull up,
connected to the pin, forces a high level (VBAT) when the headset load is not connected. At jack
insertion headset load connection (32 Ω) imposes a low level on that node (Headset left channel):
as an example HSDET = 1 mV after jack plug for VBAT = 4 V.
• Input comparator threshold voltages are defined as VTlow = VBAT/2 – 100 mV and VThigh =
VBAT/2 + 100 mV, VBATmin = 3.2 V. The plug and unplug detection remains functional if there is
no signal from HSOL amplifier output (stereo path is OFF) or if there is a signal from HSOL
(stereo path is ON): maximum level on HSOL when the stereo path is ON is 1 Vp-p which stays
far enough from the comparator threshold levels VBATmin/2 – 100 mV and VBATmin/2 +
100 mV.
• Jack plug detection is functional if a plug event occurs before the power up of the module or if the
plug event occurs after the power up of the module: analog detection part is always active if the
battery is connected. Detection interrupts will be generated once the VRIO regulator is power up
during the module power up sequence.
• A level change on HSDET pin is sensed by a Schmitt trigger to provide a jack detection signal to
the audio digital control. The audio digital control receives the detection signal and proceeds to a
digital debouncing (time: 8 ms = 256 * 32 kHz clock periods) before sensing that a plug event
happened on the jack connector.
Headset Detect Parameter/Conditions MIN TYP MAX UNIT
Low level input voltage VIL
0.3 * V
related to VBAT
VBAT
High level input voltage VIH
related to VBAT
0.7 *
VBAT
Current with pull-up -40 -31 -15 μA
GSM0308PB001 59 Version 1.03– 7/17/2007
V