User`s manual

RTD Embedded Technologies, Inc. | www.rtd.com 23 COM16155ER/COM16155RER User’s Manual
A complete list of NMEA Messages and command messages is available from the manufacturer’s website at www.linxtechnologies.com.
GPS module interface
The RXM-GNSS-TM GPS is connected to the host computer through a dedicated ISA serial port. Carrier Detect of the serial port is driven by
the 1 PPS signal. The default configuration for the serial ports is:
 9600 Baud
 8 Data bits
 No parity
 1 Stop bit
 No Flow Control
GPS Antenna
Most GPS antennas are “active” which means they have a low noise amplifier (LNA) built into the antenna that requires a power source for the
GPS module. While the COM16155 will work with a passive antenna, better performance will be achieved with an active antenna. COM16155
provides +5 V or +3.3 V for active GPS antennas.
5.1.3 DIGITAL I/O
The COM16155 has 16 bit-programmable digital I/O bits. JP4 controls a 10K Ohm pull up/down on DIO bits 1-8 and JP5 controls a 10K Ohm
pull up/down on DIO bits 9 -16.
JP3 selects if DIO0, CN7-2, is digital I/O or the GPS 1 pulse-per-second. JP3 (1-2) is installed by default configuring DIO0 as digital I/O. If JP3
is set to 2-3, the GPS 1 pulse-per-second is driven out DIO0.