Integration Manual

SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R11 System description Page 31 of 157
☞ Before the switch-on of the generic digital interface supply (V_INT) of the module, no voltage driven
by an external application should be applied to any generic digital interface of the module.
☞ Before the SARA-R4/N4 series module is fully ready to operate, the host application processor should
not send any AT command over AT communication interfaces (USB, UART) of the module.
☞ The duration of the SARA-R4/N4 series modules’ switch-on routine can vary depending on the
application / network settings and the concurrent module activities.
⚠ An abrupt removal of the VCC supply or forcing a low level on the RESET_N input once the boot of
SARA-R4/N4 series modules has been triggered may lead to an unrecoverable faulty state!
1.6.2 Module power-off
SARA-R4/N4 series modules can be cleanly switched off by:
 AT+CPWROFF command (see SARA-R4/N4 series AT Commands Manual [2]).
 Low pulse on the PWR_ON pin for a valid time period (see the SARA-R4/N4 series Data Sheet [1]).
These events listed above trigger the storage of the current parameter settings in the non-volatile memory
of the module, and a clean network detach procedure.
An abrupt under-voltage shutdown occurs on SARA-R4/N4 series modules when the VCC module supply
is removed. If this occurs, it is not possible to perform the storing of the current parameter settings in the
module’s non-volatile memory or to perform the clean network detach.
☞ It is highly recommended to avoid an abrupt removal of the VCC supply during SARA-R4/N4 series
modules normal operations.
⚠ An abrupt removal of the VCC supply during SARA-R4/N4 series modules normal operations may lead
to an unrecoverable faulty state!
An abrupt hardware shutdown occurs on SARA-R4/N4 series modules when a low level is applied on
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
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 SARA-R4/N4 series AT Commands Manual [2].