Battery Interface; User Interface; Main Display - Nokia RX-44 Service Manual

RX-44
System Module

Battery interface

The battery interface supports BP-4L battery. This interface consists of three connectors: VBAT, BSI and GND.
BSI line is used to recognize battery capacity by a battery internal pull down resistor.
Battery temperature is estimated by measuring separate battery temperature NTC via BTEMP line, which is
located on the transceiver PWB, in a place where phone temperature is most stabile.
For service purposes the device SW can be forced into local mode by using pull down resistors connected to
the BSI line.

User interface

Main display

Display module features:
The device has one display.
Video interface is used for image data transfer (video and still) and serial interface is used for sending
commands.
• 800x480 transmissive LTPS LCD display
• 65k colours used in RX-44
• a backlight incorporating 6 white LED's to illuminate the display.
• a touch screen
• Compact Display Port (CDP) for display data and serial interface (LOSSI) for commands.
The display has four different operating modes:
• Normal mode
• Sleep mode
• Partial mode
• Off
The interconnection between the LCD module and the main flex assembly is implemented with a 30-pin
board-to-board connector. Display is controlled via LCD controller using LOSSI interface (Low Speed Serial
Interface).
Image data is transferred through 3-link CDP (Compact Display Port). CDP is using differential sub-LVDS voltage
levels.
The display module does not require any tunings. Display backlights are powered with discrete SMPS.
Figure 38 800x480 transmissive LCD display
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