Integration Manual

LISA-U2 series - System Integration Manual
UBX-13001118 - R25 System description Page 15 of 182
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 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 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 [2]).
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 the u-blox AT Commands Manual [2], 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 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 the u-blox AT Commands Manual [2],
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 (typical) to VUSB_DET input (see 1.9.3)
The connected USB host forces a remote wakeup of the module as a
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 that
it is ready to send data (see 1.10, 1.12)