Graphics ClientM User Manual
110120-1000A
20
Backlight
Most LCDs include one or more cold-cathode fluorescent lamp (CCFL) tubes to backlight
the displays. Backlight inverters drive the panel backlights. These circuits are typically
external to the display and generate the several hundred volts required to drive the CCFL
tubes. Backlights can easily become the greatest source of power consumption in a
portable system.
Typically, backlight inverters include control signals to dim and turn off the backlight. To
reduce power consumption, header
provides two backlight control signals
driven by the PXA320. For electrical specifications, see
The following table describes the backlight control signals.
J8 Pin Name
Type PXA320 Signal Description
5
BKLT_ON#
OD GPIO126
Turns power on or off
6
BKLT_PWM AO PWM0
Controls backlight intensity
For details about the backlight power, see
Touch Panel
The GCM supports a 4-wire or 5-wire resistive touch panel on header
, page
Standard GCMs use the integrated PXA320 touch screen controller to drive a 4-wire
touch panel. For electrical specifications, see
. An on-board
5-wire controller is available as a volume production option.
Audio Interface
For its audio subsystem, the GCM uses an AC '97 stereo codec combined with a dual
audio amplifier. This subsystem supports an audio line in, headphones, and stereo
speakers. For electrical specifications, see
The following diagram illustrates the audio subsystem.
Graphics ClientM
J18 U
AC ’97 Codec
from PXA320
LINE_IN_L
LINE_IN_R
MIC1
AIN_R
AIN_L
LINE_OUT_L
LINE_OUT_R
HP_R
HP_L
SPKL+
SPKL-
J18 L
J17
SPKR+
SPKR-
J19
HP_IN
J100
HP_OUT_R
HP_OUT_L
Audio or
Analog GND
Summary of Contents for PXA320
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