Integration Manual

SARA-R4/N4 series - System Integration Manual
UBX-16029218 - R13 System description Page 25 of 119
VCC
PWR_ON
RESET_N
V_INT
Internal Reset
System State
BB Pads State
Operational
OFF
Tristate / Floating
ON
Operational
→
Tristate
AT+CPWROFF
sent to the module
OK
replied by the module
VCC can be
removed
Figure 10: SARA-R4/N4 series modules switch-off sequence by means of AT+CPWROFF command
VCC
PWR_ON
RESET_N
V_INT
Internal Reset
System State
BB Pads State
OFF
Tristate / Floating
ON
Operational
->
Tristate
Operational
The module starts
the switch-off routine
VCC can be
removed
Figure 11: SARA-R4/N4 series modules switch-off sequence by means of PWR_ON pin
☞
☞☞
☞ The Internal Reset signal is not available on a module pin, but it is highly recommended to monitor the V_INT pin to
sense the end of the switch-off sequence.
⚠
⚠⚠
⚠ VCC supply can be removed only after V_INT goes low: an abrupt removal of the VCC supply during SARA-R4/N4
series modules normal operations may lead to an unrecoverable faulty state!
☞
☞☞
☞ The duration of each phase in the SARA-R4/N4 series modules’ switch-off routines can largely vary depending on the
application / network settings and the concurrent module activities.
1.6.3 Module reset
SARA-R4/N4 series modules can be cleanly reset (rebooted) by:
• AT+CFUN command (see the SARA-R4/N4 series AT Commands Manual [2]).
In the case above an “internal” or “software” reset of the module is executed: the current parameter settings are saved
in the module’s non-volatile memory and a clean network detach is performed.
An abrupt hardware shutdown occurs on SARA-R4/N4 series modules when a low level is applied on RESET_N input pin
for a valid time period. 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. Then, the module remains in power-off mode as long as a switch on event
does not occur applying an appropriate low level to the PWR_ON input.
☞
☞☞
☞ It is highly recommended to avoid an abrupt hardware shutdown of the module by forcing a low level on the RESET_N
input during modules normal operation: the RESET_N line should be set low only if reset or shutdown via AT