A/D Channels; Digital Camera - Nokia NPL-4 Series Manual

NPL-4/5/RM-104
System Module and User Interface

A/D channels

The UEMEK contains the following A/D converter channels that are used for several mea-
surement purposes. The general slow A/D converter is a 10-bit converter using the
UEMEK interface clock for the conversion. An interrupt will be given at the end of the
measurement.
The UEMEK's 11-channel analog to digital converter is used to monitor charging func-
tions, battery functions, user interface and RF functions.
The monitored battery functions are battery voltage (VBATADC), battery type (BSI) and
battery temperature (BTEMP) indication.
The battery type is recognized through a resistive voltage divider. In phone there is a
100k. pull up resistor and a 75kohm BSI pull down resistor in the same line. Regardless of
the battery type the pull down resistor is always same. The battery temperature is mea-
sured equivalently from engine board by NTC pull down resistor in the BTEMP line.
The monitored RF functions are PATEMP and VCXOTEMP measurements. PATEMP input is
used to measure temperature of the RF-IC HELGO. VCXOTEMP input is used for RF PA
manufacturer identification in NPL-4/5.
AUXDET and HEADINT2 inputs can be used for keyboard scanning purposes. These inputs
are routed internally from the miscellaneous block. These lines are used for thermometer
in NPL-4/5.
The output of the backup battery, VBACK, is connected to the converter using a NMOS
switch. There is also a pulldown switch in the VBACK input, which can be used to dis-
charge the back up battery line. The pulldown switch should be disabled during the mea-
surement of the voltage level of the VBACK.

Digital camera

VGA camera module is used in NPL-4/5. Camera is connected to baseband (UPP) through
HW Accelerator IC. The camera data bus is common with display bus. External 1.8V and
2.8V regulators are used as a power supply (VDIG and VANA) for camera module and HW
accelerator. The 2.8V regulator is common for camera, compass and FM-radio.
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