LISA-U2 series - System Integration Manual
UBX-13001118 - R19
Early Production Information
System description
Page 15 of 175
1.4
Operating modes
LISA-U2 series modules have several operating modes. The operating modes are defined in Table 4 and
described in details in Table 5, 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 reference oscillator.
Active-Mode
Module processor core runs with 26 MHz as reference oscillator.
Connected-Mode
Voice or data call enabled and processor core runs with 26 MHz as 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 applying
VCC
supply (see 1.6.1) 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 1.6.2).
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 1.6.2), 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 1.6.1): 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
[2]), reducing current consumption (see 1.5.3.3).
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 1.9.2.2, 1.9.2.3).
If HW flow control is disabled by AT&K0, the
UART
CTS
line is fixed to ON state (see 1.9.2.2).
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 1.5.3.3, 1.9.2.3,
1.9.3.2, 1.9.4.2 and
u-blox AT Commands Manual
[2], AT+UPSV).
The module wakes up from idle-mode to active-mode in these events:
Automatic periodic monitoring of the paging channel for the
paging block reception according to network conditions (see
1.5.3.3, 1.9.2.3)
Automatic periodic enable of the UART interface to receive and
send data, if AT+UPSV=1 has been set (see 1.9.2.3)
RTC alarm occurs (see
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 1.9.2.3)
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 1.9.2.3)
DTR
input set ON by DTE if AT+UPSV=3 has been set (see 1.9.2.3)
USB detection, applying 5 V (typ.) to
VUSB_DET
input (see 1.9.3)
The connected USB host forces a remote wakeup of the module
as USB device (see 1.9.3)
The connected SPI master indicates by the
SPI_MRDY
input signal
that it is ready for transmission or reception (see 1.9.4)
The connected u-blox GNSS receiver indicates by the
GPIO3
pin
