User Guide

CCS Technical Documentation System Module

RH-27

Functional Description

Modes of Operation

The RH-27 baseband engine has five different operating modes:

1 No supply

2Acting Dead

3Active

4 Sleep

5 Charging

No Supply Mode

In NO_SUPPLY mode, the phone has no supply voltage. This mode is due to the discon-

nection of the main battery or a low battery voltage level. The phone exits from

NO_SUPPLY mode when a sufficient battery voltage level is detected. The battery voltage

can rise either by connecting a new battery with VBAT > VMSTR+, or by connecting a

charger and charging the battery voltage to above VMSTR+.

Acting DEAD Mode

If the phone powered off when the charger is connected, the phone is powered on and

enters a state called Acting Dead. In this mode, no RF circuitry is powered up. To the user,

the phone acts as if it is switched off. The phone issues a battery-charging alert and/or

shows a battery charging indication on the display to acknowledge to the user that the

battery is charging.

Active Mode

In active mode, the phone is in normal operation, scanning for channels, listening to a

base station, transmitting, and processing information. There are several sub-states in

the active mode depending on if the phone is in burst reception, burst transmission, etc.

In active mode, SW controls the RF regulators by writing the correct values into the UEM

control registers. VR1A/B and VR2 can be enabled or disabled. VR4 - VR7 can be

enabled, disabled, or forced into low quiescent current mode. VR3 is always enabled in

active mode.

Sleep Mode

The phone enters Sleep mode when both the MCU and the DSP are in stand-by mode.

Both processors control sleep. When the SLEEPX low signal is detected, the UEM enters

SLEEP mode. In this mode, the VCORE, VIO and VFLASH1 regulators are put into low qui-

escent current mode. All RF regulators — with the exception of VR2 and VR3 — are dis-

abled in sleep mode. When the SLEEPX is set high and is detected by the UEM, the phone

enters ACTIVE mode and all functions are activated. Sleep mode is exited either by the

expiration of a sleep clock counter in the UEM, or by some external interrupt generated

by a charger connection, key press, or headset connection among other things. While in