Nokia 6220 Service Manual

RH-20

Company confidential

System Module and User Interface

CCS Technical Documentation

Page 28

  Nokia Corporation.

Issue 1  10/2003

described in section Power Up and Reset. After baseband is powered on, an interrupt is 
given to MCU. When RTC alarm occurs during power on state the interrupt for MCU is 
generated.

The UEM contains the following A/D converter channels that are used for several mea-
surement purpose. The general slow A/D converter is a 10 bit converter using the UEM 
interface clock for the conversion. An interrupt will be given at the end of the measure-
ment.

The UEM’s 11-channel analog to digital converter is used to monitor charging functions, 
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

Ω pull up resistor in the BSI line and the battery has a pull down resistor in the 

same line. Depending on the battery type the pull down resistor value varies. The battery 
temperature is measured equivalently except that the battery has a NTC pull down resis-
tor in the BTEMP line.

KEYB1&2 inputs are used for keyboard scanning purposes. These inputs are also routed 
internally to the miscellaneous block.

The monitored RF functions are PATEMP and VCXOTEMP detection. PATEMP input is used 
to measure temperature of the RFIC, the Helgo.