LISA-U2 series - System integration manual
UBX-13001118 - R27
System description
Page 15 of 183
C1-Public
1.4
Operating modes
LISA-U2 series modules have several operating modes. The operating modes are defined in
and described in details in
, providing general guidelines for operation.
General Status
Operating Mode
Definition
Power-down
Not-Powered Mode
VCC
supply not present or below operating range: module is switched off.
Power-Off Mode
VCC
supply within operating range and module is switched off.
Normal Operation
Idle mode
Module processor core runs with 32 kHz as the reference oscillator.
Active mode
Module processor core runs with 26 MHz as the reference oscillator.
Connected mode
Voice or data call enabled and processor core runs with 26 MHz as the
reference oscillator.
Table 4: Module operating modes definition
Operating mode Description
Transition between operating modes
Not-powered
Module is switched off.
Application interfaces are not
accessible.
Internal RTC timer operates only if a
valid voltage is applied to
V_BCKP
pin.
When
VCC
supply is removed, the module enters not-powered mode.
When in not-powered mode, the module cannot be switched on by a
low pulse on
PWR_ON
input, by a rising edge on
RESET_N
input, or by
a preset RTC alarm.
When in not-powered mode, the module can be switched on by
applying
VCC
supply (see
) so that the module switches from
not-powered to active mode.
Power-off
Module is switched off: normal
shutdown by an appropriate power-
off event (see
Application interfaces are not
accessible.
Only the internal RTC timer in
operation.
When the module is switched off by an appropriate power-off event
(see
), the module enters power-off mode from active mode.
When in power-off mode, the module can be switched on by a low
pulse on
PWR_ON
input, by a rising edge on
RESET_N
input, or by a
preset RTC alarm (see
): module switches from power-off to
active mode.
When
VCC
supply is removed, the module switches from power-off
mode to not-powered mode.
Idle
Application interfaces are disabled:
the module does not accept data
signals from an external device
connected to the module.
The module automatically enters idle
mode whenever possible if power
saving is enabled by AT+UPSV (see
u-blox AT commands manual
),
reducing current consumption (see
If HW flow control is enabled (default
setting) and AT+UPSV=1 or
AT+UPSV=3 has been set, the UART
CTS
line indicates when the UART is
enabled (see
If HW flow control is disabled by
AT&K0, the UART
CTS
line is fixed to
ON state (see
Power saving configuration is not
enabled by default: it can be enabled
by AT+UPSV (see the u-blox AT
commands manual
The module automatically switches from active mode to idle mode
whenever possible if power saving is enabled (see
and the u-blox AT commands manual
, AT+UPSV).
The module wakes up from idle mode to active mode for these events:
Automatic periodic monitoring of the paging channel for the paging
block reception according to network conditions (see
Automatic periodic enable of the UART interface to receive and send
data, if AT+UPSV=1 has been set (see
RTC alarm occurs (see the u-blox AT commands manual
AT+CALA)
Data received on UART interface, if HW flow control has been
disabled by AT&K0 and AT+UPSV=1 has been set (see
RTS
input set ON by the DTE if HW flow control has been disabled by
AT&K0 and AT+UPSV=2 has been set (see
DTR
input set ON by DTE if AT+UPSV=3 has been set (see
USB detection, applying 5 V (typical) to
VUSB_DET
input (see
The connected USB host forces a remote wakeup of the module as a
USB device (see
The connected SPI host indicates by the
SPI_MRDY
input signal that
it is ready for transmission or reception (see
The connected u-blox GNSS receiver indicates by the
GPIO3
pin that
it is ready to send data (see
