Als Interface; Asics; Rap3G Asic - Nokia RM-57 Service Manual

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PWM
GenOut3

ALS interface

Ambient Light Sensor (ALS) is located in the upper part of the phone. It consists of a lightguide (part of front
cover), phototransistor (V4400)+ resistor (R4401), NTC + resistors (R4400, R4402, R4403) and RETU EM ASIC
(N2200). Information of ambient lighting is used to control 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.
Symbol R1
Value 5 kOhm

ASICs

RAP3G ASIC

RAP3G ASIC is a 3G Radio Application Processor. RAM memory is integrated into RAP3G.
In general RAP3G consists of three separate parts:
• Processor subsystem (PSS) that includes the main processor and related functions
• MCU peripherals that are mainly controlled by MCU
• DSP peripherals that are mainly controlled by DSP
Page 9–22
From
TAHVO
TAHVO
Figure 106 ALS HW implementation
Table 19 ALS resistor values
R2 R3
15 kOhm 30 kOhm
Company Confidential
Copyright ©2005 Nokia. All Rights Reserved.
To
J2309, N2301
V2300
R4 R5
470
50 kOhm kOhm
Voltage
PWM 0%-100%,
1.8V
0V / 1.8V
R6
100
kohm
RM-57/58
System Module
Function
Current PWM
control (16 steps)
Keyboard LEDs ON
(1.8V) /OFF (0V)
R7 NTC-res
470
kohm 47 kOhm
Issue 1