Als Interface - Nokia n80 User Manual

RM-91; RM-92
System Module
GenOut 1
Genout 0
Typically, keyboard LEDs are turned ON only in dark ambient light conditions. The ITU keymat LEDs are
extinguished when the device detects that the slide has been closed.

ALS interface

Ambient Light Sensor (ALS) is located in the upper part of the phone. It consists of the following components:
• lightguide (part of the front cover)
• phototransistor (V4400) + resistor (R4401)
• NTC + resistors (R4400, R4402, R4403)
• EM ASIC (N2200)
Information on ambient lighting is used to control the backlights of the phone:
• Keypad lighting is switched on only when the environment is dark / dim
• Display backlights are dimmed, when the environment is dark / dim
The ambient light sensor itself is a photo transistor, which is temperature-compensated by an external NTC
resistor. N2200 reads the light sensor (LS) and temperature (LST) results.
ALS calibration is not possible in the service points. ALS is serviced by replacing faulty phototransistors.
Issue 1
Table 15 LED driver control signals
From
N2300
N2300
COMPANY CONFIDENTIAL
Copyright © 2006 Nokia. All rights reserved.
To
V4405
V4404
Nokia Customer Care
Voltage
0V/1.8V
0V/1.8V
Function
S60 LED control
ITU LED control
Page 9 –21