SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R26
System description
Page 77 of 217
GNSS supply enable
:
The
GPIO2
is by default configured by AT+UGPIOC command to enable or disable the supply of the u-blox
GNSS receiver connected to the cellular module.
The
GPIO1
,
GPIO3
,
GPIO4
pins and, on SARA-U2 series only, also the
SIM_DET
pin, can be configured to
provide the “GNSS supply enable” function, alternatively to the default
GPIO2
pin, setting the parameter
<gpio_mode> of the AT+UGPIOC command to 3. The “GNSS supply enable” mode can be provided only on
one pin per time: it is not possible to simultaneously set the same mode on another pin.
The pin configured to provide the “GNSS supply enable” function is set as
o
High, to switch on the u-blox GNSS receiver, if AT+UGPS parameter <mode> is set to 1
o
Low, to switch off the u-blox GNSS receiver, if AT+UGPS parameter <mode> is set to 0 (default)
GNSS data ready
:
Only the
GPIO3
pin provides the “GNSS data ready” function, to sense when a u-blox GNSS receiver
connected to the cellular module is ready to send data via the DDC (I
2
C) interface, setting the parameter
<gpio_mode> of AT+UGPIOC command to 4.
The pin configured to provide the “GNSS data ready” function is set as
o
Input, to sense the line status, waking up the cellular module from idle mode when the u-blox GNSS
receiver is ready to send data via the DDC (I
2
C) interface, if the first AT+UGPS parameter is set to 1 and
the first AT+UGPRF parameter is set to 16
GNSS RTC sharing
:
Only the
GPIO4
pin provides the “GNSS RTC sharing” function, to provide an RTC (Real Time Clock)
synchronization signal to the u-blox GNSS receiver connected to the cellular module, setting the parameter
<gpio_mode> of AT+UGPIOC command to 5.
The pin configured to provide the “GNSS RTC sharing” function is set as:
o
Output, to provide an RTC (Real Time Clock) synchronization signal to the u-blox GNSS receiver if the
first AT+UGPS parameter is set to 1 and the first AT+UGPRF parameter is set to 32
o
Low, otherwise (default setting)
SIM card detection
:
The
SIM_DET
pin of SARA-G3 modules is by default configured to detect the SIM card mechanical presence
and this configuration cannot be changed by AT command.
The
SIM_DET
pin of SARA-U2 modules is by default configured to detect the SIM card mechanical presence
as default setting of the AT+UGPIOC command: the “SIM card detection” function is enabled as the
parameter <gpio_mode> of AT+UGPIOC command is set to 7 (default setting).
The
SIM_DET
pin configured to provide the “SIM card detection” function is set as
o
Input with an internal active pull-down enabled, to sense the SIM card mechanical presence
The
SIM_DET
pin can sense the SIM card mechanical presence only if properly connected to the mechanical
switch of a SIM card holder as described in section 2.5:
o
Low logic level at
SIM_DET
input pin is recognized as SIM card not present
o
High logic level at
SIM_DET
input pin is recognized as SIM card present
An Unsolicited Result Code (URC) can be generated each time that there is a change of status (for more
details, see the “simind” value of the <descr> parameter of +CIND and +CMER commands in the
u-blox AT
Commands Manual
[3]). SARA-U2 modules provide the additional function “SIM card hot insertion/removal”
on the
SIM_DET
pin, which can be enabled using the AT+UDCONF=50 command (for more details, see the
u-blox AT Commands Manual
[3]): in this case the SIM interface of the SARA-U2 modules is disabled when a
Low logic level is recognized at
SIM_DET
input pin (within 20 ms from the start of the Low level) and it is
enabled when an High logic level at
SIM_DET
input pin is recognized.
SARA-G3 modules do not support the additional function “SIM card hot insertion/removal”
