Figure 76 Display block diagram
Backlight and illumination
This device has two backlighting systems; one for the display and one for the HW keys and other illumination
zones.
Backlighting for HW keys
The L5521 LED contoller is used for backlightning the HW keys . There is one LP5521 in the reference HW
making it possible to have up to three LED zones. It can also drive the RGB LED.
RM-505; RM-506
System Module and User Interface
Issue 1
COMPANY CONFIDENTIAL
Page 8 –27
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