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Signal name X4401 Pin # X4400 Pin #

Joystick_Left 19

Joystick_Up 15

Joystick_Push 17

VLEDOUT2 1

SETCURR2 2

Display and keyboard backlight

The device has one Led Driver (SMPS) that is used to drive both displays and keyboard LEDs. LEDs on display

modules and on keyboard are connected so that there are 4 LEDs on K2 (in series), 3 LEDs on Jordan (in series)

and 4 LEDs on keyboard (in series). These circuits are connected parallel to Led Driver output.

Current adjustment of the driver is done from the display LED branch, and keyboard current also depends on

the display brightness.

In a typical use case, keyboard LEDs are turned ON only in dark ambient lighting conditions.

K2 and Jordan backlights can´t be turned on at the same time.

Control signals for LED driver are:

From To Voltage Function

GenOut1 TAHVO R2302 (10k) 0V / 1.8V Maximum current

control (0V ->max

curr.)

GenOut2 TAHVO R2301 (4k7) 0V / 1.8V

PWM TAHVO J2309, N2301 PWM 0%-100%,

1.8V

Current PWM

control (16 steps)

GenOut3 TAHVO V2300 0V / 1.8V Keyboard LEDs ON

(1.8V) /OFF (0V)

GenIO46 Rap3G --> BLS Display backlight

select (1 = K2

backlights on, 0 =

Jordan backlights

on)

ALS interface

Ambient Light Sensor (ALS) is located in the fold part of the phone. It consists of a lightguide (part of front cover),

components of 1LB PWB: phototransistor (V1000)+ resistor (R1006), NTC + resistors (R1004, R1005, R1007) and

RETU EM ASIC (N2200)on 1HU PWB (Gromit engine). Information of ambient lighting is used to control the

backlights of the phone:

• Keypad lighting is switched on only when environment is dark / dim

• Display backlights are dimmed, when environment is dark / dim

Ambient light sensor itself is a photo transistor which is temperature-compensated by an external NTC resistor.

Retu with its ADC reads the light sensor (LS) and temperature (LST) results.

ALS calibration is not possible in the service points. It is replaced by using selected phototransistors as spare

parts.

RM-42

Nokia Customer Care System Module

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