LISA-U2 series - System integration manual
UBX-13001118 - R27
System description
Page 41 of 183
C1-Public
and set to high impedance during module power down mode, when the external reset is forced low,
and during the power-on sequence.
1.6.2
Module power-off
The power-off sequence of LISA-U2 series modules can be correctly started, so that the current
parameter settings are saved in the module’s non
-volatile memory and a clean network detach is
performed, in one of these ways:
•
AT+CPWROFF command (more details in the u-blox AT commands manual
•
Low pulse on the
PWR_ON
pin for at least 1 second
An over-temperature or an under-temperature shutdown occurs 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 the section
and the u-blox AT commands manual
, +USTS AT command.
An abrupt under-voltage shutdown occurs on LISA-U2 modules when the
VCC
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: the power-off sequence
of the module must be properly started as described above (e.g. by means of the AT+CPWROFF
command), and a clean
VCC
supply must be maintained at least until the end of the 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 LISA-U2 series modules when a low level is applied to the
RESET_N
pin. In this case, the current parameter settings are not saved in the module’s non
-volatile
memory and a clean 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 a 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
