Μsd Card Interface; User Interface; Display; Keyboard - Nokia RM-272 Service Manual

RM-272; RM-273
System module
µSD card interface
The µSD card is connected to the engine by an external level shifter and ESD protection filter. Supplied
voltages:
• VMMC: 2.85 V (from level shifter)
• VIO: 1.8 V (from Retu)
The card removal is detected by a push detect switch.

User interface

Display

The display unit comprises a parallel interface.

Keyboard

All keys are placed on the main PWB.
• Numeric keys
• Navigation key, Soft keys, Start, and End
• Power switch
• Volume up and down switch

Display and keypad backlight

There are two sets of LEDs illuminating the display and the keypads:
• Display LEDs, 4pcs
• Main keypad on PWB, 4 pcs, white colour
All sets share the same driver. None of the keypads can be illuminated without the LCD backlight being turned
on.

Audio concept

Audio concept
The functional core of the audio hardware is built around two ASICs; RAP engine and Retu.
Retu provides an interface for the trancducers and the AV connector.
There are three audio transducers:
• 1 dynamic earpiece
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