SARA-R4 series - System integration manual
UBX-16029218 - R20 System description Page 29 of 128
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1.6.2 Module power-off
SARA-R4 series modules can be gracefully switched off by:
• AT+CPWROFF command (see SARA-R4 series AT commands manual [2]).
• Low pulse on the PWR_ON / PWR_CTRL pin for a valid time period (for detailed characteristics see
the SARA-R4 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 emergency faster and safe power-off procedure of SARA-R422, SARA-R422S, SARA-R422M8S
modules, without proper network detach, can be triggered by:
• AT+CFUN=10 command (see SARA-R4 series AT commands manual [2])
• Toggling the GPIO input pin configured with the fast and safe power-off function (see section 1.11)
☞ The graceful switched off procedure triggered by the +CPWROFF AT command or by proper low
pulse at the PWR_ON / PWR_CTRL input pin must be preferred rather than the faster and safe
power-off procedure triggered by the AT+CFUN=10 command or by toggling the configured GPIO
pin, as the faster and safe power-off procedure is intended to be used in case of emergency only.
An abrupt under-voltage shutdown occurs on SARA-R4 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 series
modules normal operations.
⚠ An abrupt removal of the VCC supply during SARA-R4 series modules normal operations may lead
to an unrecoverable faulty state!
An abrupt hardware shutdown occurs on SARA-R410M and SARA-R412M 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 series AT commands
manual [2].
⚠ Forcing a low level on the RESET_N input during SARA-R4 series modules normal operations may
lead to an unrecoverable faulty state!