User Guide

Nokia Customer Care Troubleshooting - Baseband

6015/6015i/6016i/6019i (RH-55), 6012 (RM-20)

Figure 3: Power up

Power Up - Power Key

When the power key is pressed, the UEM enters the power up sequence. Pressing the

power key causes the PWRONX pin on the UEM to be grounded. The UEM PWRONX

signal is not part of the keypad matrix. The power key is only connected to the UEM,

which means that when pressing the power key, an interrupt is generated to the UPP

that starts the MCU. The MCU then reads the UEM interrupt register and notices that it

is a PWRONX interrupt. Then the MCU reads the status of the PWRONX signal using the

UEM control bus (CBUS). If the PWRONX signal stays low for a specific duration, the

MCU accepts this as a valid power on state and continues with the SW initialization of

the baseband. If the power on key does not indicate a valid power on situation, the MCU

powers off the baseband.

Power Up - Charger

In order to be able to detect and start charging in the case where the main battery is

fully discharged (empty) and hence the UEM has no supply (NO_SUPPLY or BACKUP

mode of UEM), charging is controlled by START-UP CHARGING circuitry.

Whenever a VBAT level is detected to be below master reset threshold (V

MSTR-

charging starts and is controlled by START_UP charge circuitry. Connecting a charger