Sleep Mode; Active Mode; Charging Mode - Nokia 6255 Description And Troubleshooting

Nokia Customer Care

Sleep Mode

When the SLEEPX signal is detected low by the UEME, the mobile terminal enters sleep
mode. In sleep mode, both processors (MCU and DSP) are in stand-by mode. The mobile
terminal enters sleep mode only when both processors make this request. The following
processes occur during sleep mode:
• VIO and VFLASH1 regulators are put into low quiescent current mode
• VCORE enters LDO mode
• VANA and VFLASH2 regulators are disabled
• All RF regulators are disabled
• VCTCXO (19.2MHz clock) is shut down
• 32kHz sleep clock oscillator is used as the baseband reference clock
The average current consumption of the mobile terminal in this mode can vary
depending on the software state (e.g., slot cycle 0,1, or 2, and if the mobile terminal is
working on IS95 or IS2000 for CDMA). However, on average the current consumption is
about 1.3mA in sleep mode and 100mA in active mode.
Sleep mode is exited either by the expiration of a sleep clock counter in the UEME or by
some external interrupt (e.g., charger connection, key press, headset connection). Any of
these conditions cause a high SLEEPX signal, which is detected by the UEME, and causes
the mobile terminal to enter active mode where all functions are activated.

Active Mode

During active mode, the mobile terminal 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 the mobile terminal present state of the
mobile terminal, such as burst reception, burst transmission, if the DSP is working, etc.
In active mode, software controls the UEME radio frequency (RF) regulators (VR1A and
VR1B), which can be enabled or disabled. These regulators work via the UEME charge
pump. VSIM can be enabled or disabled, and its output voltage can be programmed to be
1.8V or 3.0V. VR2 and VR4—VR7 can be enabled, disabled, or forced into low quiescent
current mode. VR3 is always enabled in active mode, disabled during sleep mode, and
cannot be controlled by the software in the same way as the other regulators. VR3 only
turns off if both processors (DSP and MCU) request to be in sleep mode.

Charging Mode

Charging mode can be performed in parallel with any other operating mode. A BSI
resistor inside the battery indicates the battery type and size and corresponds to a
specific battery capacity.
The battery voltage, temperature, size, and charging current are measured by the UEME
and controlled by the Energy Management (EM) charging algorithm.
Issue 2 05/2005
©2005 Nokia Corporation
6255/6255i6256/6256i (RM-19)
Baseband Description and Troubleshooting
Company Confidential Page 11