LISA-U2 series - System Integration Manual
UBX-13001118 - R19
Early Production Information
System description
Page 97 of 175
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 will be set as
o
Output, to provide an RTC (Real Time Clock) synchronization signal to the u-blox GNSS receiver if
the parameter <mode> of AT+UGPS command is set to 1 and parameter <GPS_IO_configuration>
of AT+UGPRF command is set to 32
o
Output / Low, otherwise (default setting)
The pin that provides the “GNSS RTC sharing” function must be connected to the RTC synchronization
input of the u-blox GNSS receiver (i.e. the pin EXTINT0 of the u-blox GNSS receiver) on the application
board.
SIM card detection
:
The
GPIO5
pin is by default configured by AT+UGPIOC command to detect SIM card presence.
Only the
GPIO5
pin can be configured to provide the “SIM card detection” function, setting the parameter
<gpio_mode> of AT+UGPIOC command to 7 (default setting).
The pin configured to provide the “SIM card detection” function is set as
o
Input with an internal active pull-down enabled, to sense SIM card presence
The pin must be connected on the application board to SW2 pin of the SIM card holder, which must provide
2 pins for the mechanical card presence detection, with a 470 k
Ω
pull-down resistor. SW1 pin of the SIM
card holder must be connected to
V_INT
pin of the module, by a 1 k
Ω
pull-up resistor. See Figure 52 and
section 1.8 for the application circuit. The
GPIO5
signal will be pulled low by the pull-down when a SIM
card is not inserted in the holder, and will be pulled high by the pull-up when a SIM card is present.
The
GPIO5
pin is configured as an external interrupt to detect SIM card presence. 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
All LISA-U2 series modules provide the additional function “SIM card hot insertion/removal” on the
GPIO5
pin, which can be enabled using the AT+UDCONF=50 command (for more details see the
u-blox AT
Commands Manual
Network status indication
:
GPIO1
,
GPIO2
,
GPIO3
,
GPIO4
or
GPIO5
can be configured to indicate network status (i.e. no service,
registered home 2G network, registered home 3G network, registered visitor 2G network, registered visitor
3G network, voice or data 2G/3G call enabled), setting the parameter <gpio_mode> of AT+UGPIOC
command to 2.
No GPIO pin is by default configured to provide the “Network status indication” function.
The “Network status indication” 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 “Network status indication” function is set as
o
Continuous Output / Low, if no service (no network coverage or not registered)
o
Cyclic Output / High for 100 ms, Output / Low for 2 s, if registered home 2G network
o
Cyclic Output / High for 50 ms, Output / Low for 50 ms, Output / High for 50 ms, Output / Low for
2 s, if registered home 3G network
o
Cyclic Output / High for 100 ms, Output / Low for 100 ms, Output / High for 100 ms, Output / Low
for 2 s, if registered visitor 2G network (roaming)
o
Cyclic Output / High for 50 ms, Output / Low for 50 ms, Output / High for 50 ms, Output / Low for
100 ms, if registered visitor 3G network (roaming)
o
Continuous Output / High, if voice or data 2G/3G call enabled
