User Guide

Nokia Customer Care Baseband Description and Troubleshooting

2115i/2116/2116i (RH-66)

Figure 3: Measured power-on sequence and timing

Power Up

The mobile terminal can power up using the power key, a charger, or an RTC alarm.

Power Key

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

power key causes the PWRONX pin on the UEMC to ground. The UEMC PWRONX signal is

not part of the keypad matrix. The power key is only connected to the UEMC. This means

that when pressing the power key an interrupt is generated to the UPP that starts the

MCU. The MCU then reads the UEMC interrupt register and notices that it is a PWRONX

interrupt. The MCU reads the status of the PWRONX signal using the UEMC control bus

(CBUS). If the PWRONX signal stays low for a certain time the MCU accepts this as a

valid power-on state and continues with the software baseband initialization. If the

power key does not indicate a valid power-on situation, the MCU powers off the

baseband.

Charger

Charging is controlled by start-up charging circuitry in order to detect and start charging

in cases where the main battery is empty and the UEMC has no supply (NO_SUPPLY or

BACKUP mode).