LENA-R8 series - System integration manual
UBX-22015376 - R02
System description
Page 22 of 116
C1-Public
☞
It is highly recommended to avoid an abrupt
VCC
power removal during cellular system normal
operations. It is highly recommended to start the graceful switch-off procedure as indicated
above, and then held a proper
VCC
supply voltage at least until the end of the modules’ internal
switch-off sequence, which occurs when the
V_INT
supply output is switched off by the module.
An over-temperature or an under-temperature shutdown occurs on LENA-R8 series modules cellular
system 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 AT commands manual
, +USTS AT command.
describe the LENA-R8 series modules cellular system switch-off sequence
started by AT+CPWROFF command and by
PWR_ON
input pin, allowing storage of current parameter
settings in the module’s non
-volatile memory and a clean network detach, with the following phases:
•
When the +CPWROFF AT command is sent, or when a low pulse with appropriate time duration is
applied at the
PWR_ON
input pin, the module starts the switch-off routine.
•
Then, if the +CPWROFF AT command has been sent, the module returns "OK" on the AT interface:
the switch-off routine is in progress.
•
At the end of the switch-off routine, all the digital pins are tri-stated and all the internal voltage
regulators are turned off, including the generic digital interfaces supply (
V_INT
).
•
Then, the module remains in switch-off mode as long as a switch-on event does not occur
(applying a low level to
PWR_ON
input pin), and it enters not-powered mode if the
VCC
supply is
removed.
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 reply
Switch-off in progress
VCC can be
removed
Figure 13: LENA-R8 series modules switch-off sequence by 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 14: LENA-R8 series modules switch-off sequence by PWR_ON pin
☞
The Internal Reset signal is not available on a module pin, but it is highly recommended to monitor:
o
the
V_INT
pin, or
o
the UART break condition,
to detect the end of the LENA-R8 series module cellular system switch-off sequence
☞
It is highly recommended to avoid an abrupt removal of the
VCC
supply before the end of the
cellular system switch-off sequence, which occurs when the
V_INT
supply output is switched off.
☞
The duration of each phase in the LENA-R8 series cellular system switch-off routines can largely
vary depending on the application / network settings and the concurrent module activities.
