SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R08
Objective Specification
System description
Page 34 of 188
1.6.2
Module power-off
1.6.2.1
Switch-off events
The SARA-G3 and SARA-U2 series modules can be properly switched off by:
AT+CPWROFF command (more details in
u-blox AT Commands Manual
[3]).
The SARA-U2 series modules can be properly switched off also by:
Low pulse on the
PWR_ON
pin, which is normally set high by an external pull-up, for a valid time period
(see the
SARA-U2 series Data Sheet
[2] for the detailed electrical characteristics of the
PWR_ON
input).
In both the cases listed above, the current parameter settings are saved in the module’s non-volatile memory and
a proper network detach is performed: these are the correct ways to switch off the modules.
An abrupt under-voltage shutdown occurs on SARA-G3 and SARA-U2 series modules when the
VCC
module
supply is removed, but in this case the current parameter settings are not saved in the module’s non-volatile
memory and a proper network detach cannot be performed.
It is highly recommended to avoid an abrupt removal of the
VCC
supply during SARA-G3 and SARA-U2
series modules normal operations: the power off procedure must be properly started by the appplication,
as by the AT+CPWROFF command, waiting the command response for a proper time period (see
u-blox
AT Commands Manual
[3]), and then a proper
VCC
supply must be held at least until the end of the
modules’ internal power off sequence, which occurs when the generic digital interfaces supply output
(
V_INT
) is switched off by the module.
An abrupt hardware shutdown occurs on SARA-U2 modules when a low level is applied to the
RESET_N
input.
In this case, the current parameter settings are not saved in the module’s non-volatile memory and a proper
network detach is not performed.
It is highly recommended to avoid an abrupt hardware shutdown of the module by forcing a low level on
the
RESET_N
input pin during module normal operation: the
RESET_N
line should be set low only if reset
or shutdown via AT commands fails or if the module does not reply to a specific AT command after a time
period longer than the one defined in the
u-blox AT Commands Manual
An over-temperature or an under-temperature shutdown occurs on SARA-G3 and SARA-U2 series modules
when the temperature measured within the cellular module reaches the dangerous area, if the optional Smart
Temperature Supervisor feature is enabled and configured by the dedicated AT command. For more details see
section 1.13.10 and to the
u-blox AT Commands Manual
[3], +USTS AT command.
The Smart Temperature Supervisor feature is not supported by SARA-G300 and SARA-G310.
