Power Up; Power Key; Charger - Nokia RH-66 Troubleshooting Manual

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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).
Issue 1 03/2005
Figure 3: Measured power-on sequence and timing
©2005 Nokia Corporation
2115i/2116/2116i (RH-66)
Baseband Description and Troubleshooting
Company Confidential Page 9