LENA-R8 series - System integration manual
UBX-22015376 - R02
System description
Page 23 of 116
C1-Public
1.7.3
Cellular system reset
LENA-R8 series modules cellular system can be gracefully reset (rebooted) by:
•
AT+CFUN=16 command (see the u-blox AT commands manual
other possible options).
This event causes
an “internal” or “software” reset of the module, including the power management
unit. The current parameter settings are saved in the module’s non
-volatile memory and a proper
network detach is performed: this is the correct way to reset the modules.
An abrupt hardware reset occurs on LENA-R8 series modules
’
cellular system, without storage of the
current parameter settings and without a clean network detach, when:
•
Forcing a low level at the
RESET_N
input pin, which is normally set high by an internal pull-up, for
a valid time period (see the LENA-R8 series data sheet
RESET_N
input line low time to trigger
cellular system abrupt reset / reboot).
The
RESET_N
line is intended to be driven by open drain, open collector or contact switch.
☞
It is highly recommended to avoid an abrupt hardware reset of the module by forcing a low level on
the
RESET_N
input (see LENA-R8 series data sheet
RESET_N
low time to trigger cellular
system reset) during cellular system normal operation: the
RESET_N
line should be set low only if
reset via AT commands fails, or if the module does not provide a reply to a specific AT command
after a time period longer than the one defined in the AT commands manual
The
RESET_N
input line is intended to be driven by open drain, open collector, or contact switch.
As described in
, the
RESET_N
input line is internally pulled up. The input voltage thresholds
are different from the other generic digital interfaces. Detailed electrical characteristics are described
in the LENA-R8 series data sheet
Baseband
processor
18
RESET_N
LENA-R8 series
Reset
shutdown
Power
management
Reset
shutdown
Figure 15: LENA-R8 series RESET_N input equivalent circuit description
1.8
Cellular antenna interface
1.8.1
Cellular antenna RF interface (ANT)
LENA-R8 series modules provide one cellular RF interfaces for connecting the external antenna:
•
The
ANT
port represents the RF input/output for transmission and reception of RF signals.
The
ANT
port has a 50
nominal characteristic impedance and must be connected to the cellular
Tx / Rx antenna through a 50
transmission line to allow proper RF transmission / reception.
