User's Manual

GE910 Hardware User Guide
GE910 Hardware User GuideGE910 Hardware User Guide
GE910 Hardware User Guide
1vv0300962 Rev.9-bis3 2013-05-20
Reproduction forbidden without Telit Communications S.p.A. written authorization - All Rights Reserved page 45 of 87
Mod. 0805 2011-07 Rev.2
7.2. GNSS Signals Pinout
GNSS SECTION
R9
ANTENNA GNSS - GNSS Antenna (50 ohm) RF
G14
GNSS_EN* I External GNSS ON-OFF VBATT ref.
Open Colector active
low
J14
GNSS_NMEA_TX O UART NMEA Output 1.8V
UART3 or
GNSS_BOOT
K14
GNSS_NMEA_RX I UART NMEA Input 1.8V UART3
R7
GNSS_LNA_EN O GNSS External LNA Enable 1.8V Active Antenna Control
7.3. Turning ON/OFF the GNSS module only in standalone mode
Turning ON/OFF the GNSS device can be done in two ways:
• via AT command (see GE910 Software User Guide, AT$GPSP)
• Keeping low the external pad GNSS_EN* to Power On or releasing it to Power OFF.
NOTE:
Connect GNSS_EN* pad in an open collector configuration, since it is pulled-up to VBATT.
TIP:
To check if the GNSS device has powered on, you can use the GNSS_LNA_EN, it goes high on
power-on until first fix, and only then, it may pulse for power saving requirements.
7.4. RF Front End Design
The GE910 Module contains an integrated LNA and pre-select SAW filter. This allows the
module to work properly with a passive GPS antenna. If the antenna cannot be located near the
GE910, then an active antenna (i.e. an antenna with a built-in low noise amplifier) can be used.