Integration Manual

LISA-U series - System Integration Manual
3G.G2-HW-10002-A3 Preliminary System description
Page 88 of 160
1.12 General Purpose Input/Output (GPIO)
LISA-U1 series modules provide 5 pins (GPIO1-GPIO5), while LISA-U2 series modules provide up to 14 pins
(GPIO1-14) which can be configured as general purpose input or output, or can be configured to provide special
functions via u-blox AT commands (for further details refer to u-blox AT Commands Manual [3], +UGPIOC,
+UGPIOR, +UGPIOW, +UGPS, +UGPRF, +USPM).
The following functions are available in the LISA-U series modules:
 GSM Tx burst indication:
GPIO1 pin can be configured by AT+UGPIOC to indicate when a GSM Tx burst/slot occurs, setting the
parameter <gpio_mode> of AT+UGPIOC command to 9.
No GPIO pin is by default configured to provide the “GSM Tx burst indication” function.
The pin configured to provide the “GSM Tx burst indication” function is set as
o Output / High, since ~10 µs before the start of first Tx slot, until ~5 µs after the end of last Tx slot
o Output / Low, otherwise
The pin configured to provide the “GSM Tx burst indication” function can be connected on the application
board to an input pin of an application processor to indicate when a GSM Tx burst/slot occurs.
 GPS supply enable:
The GPIO2 is by default configured by AT+UGPIOC command to enable or disable the supply of the u-blox
GPS receiver connected to the wireless module.
The GPIO1, GPIO3, GPIO4 or GPIO5 pins can be configured to provide the “GPS supply enable” function,
alternatively to the default GPIO2 pin, setting the parameter <gpio_mode> of AT+UGPIOC command to 3.
The “GPS 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 “GPS supply enable” function is set as
o Output / High, to switch on the u-blox GPS receiver, if the parameter <mode> of AT+UGPS
command is set to 1
o Output / Low, to switch off the u-blox GPS receiver, if the parameter <mode> of AT+UGPS
command is set to 0 (default setting)
The pin configured to provide the “GPS supply enable” function must be connected to the active-high
enable pin (or the active-low shutdown pin) of the voltage regulator that supplies the u-blox GPS receiver on
the application board.
LISA-U200-00 modules version don’t support “GPS supply enable” function.
 GPS data ready:
Only the GPIO3 pin provides the “GPS data ready” function, to sense when a u-blox GPS receiver connected
to the wireless 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 “GPS data ready” function will be set as
o Input, to sense the line status, waking up the wireless module from idle-mode when the u-blox GPS
receiver is ready to send data via the DDC (I
2
C) interface; this is possible if the parameter <mode>
of AT+UGPS command is set to 1 and the parameter <GPS_IO_configuration> of AT+UGPRF
command is set to 16
o Tri-state with an internal active pull-down enabled, otherwise (default setting)
The pin that provides the “GPS data ready” function must be connected to the data ready output of the
u-blox GPS receiver (i.e. the pin TxD1 of the u-blox GPS receiver) on the application board.