Operation OEM6 Cards and Enclosures
Chapter 4
OEM6 Family Installation and Operation User Manual Rev 12
53
Configure COM 1, 2 and IMUCOM
COM1, COM2 and the IMUCOM ports can communicate using the RS-422 protocol in addition to the
standard RS-232 protocol. On the OEM638, the IMUCOM port is equivalent to COM6.
There are 3 ways to select between RS-232 and RS-422 protocol for the various ports (default is RS-232).
1. When the receiver is powered on or reset, the user input pin USERIO1 is sampled to determine operation
of COM1. If USERIO1 is low, COM1 operates in RS-232. If USERIO1 is high, COM1 operates in RS-422.
Only COM1 can be selected in this manner.
2. A Configuration Code obtained from NovAtel Customer Support can be installed in the receiver to select
the protocol for each port. This method overrides the USERIO1 selection method. The protocol for
COM1, COM2 and IMUCOM can be independently selected.
3. The
SERIALPROTOCOL
command can be used to select RS-232 or RS-422 for any of the 3 COM ports.
This method overrides the protocol set using the previous two methods.
The first two methods set the protocol mode at boot time so there is virtually no time that the communication
lines are in an indeterminate or incorrect state.
For the third method, the commands are executed after the receiver has completed booting so the
communication lines may be configured incorrectly during the time taken to boot and before the command
can be processed. For automatic configuration, the
SERIALPROTOCOL
command can be saved using the
SAVECONFIG command.
Refer to the
OEM6 Firmware Reference Manual
(OM-20000129) for command details. Refer to
on page 18 for contact information.
4.1.2
Communicating with a Remote Terminal
One method of communicating with the receiver is through a remote terminal. The receiver is pre-wired to
allow RS-232 interface with a data terminal. To communicate with the terminal, the receiver requires only the
RX, TX and GND lines be used. Handshaking is not required but is an option. Ensure the terminal’s
communications set up matches the receiver’s RS-232 settings.
4.1.3
Communicating with a Computer
A computer can emulate a remote terminal as well as provide the added flexibility of supporting multiple
command batch files and data logging storage files. Use any standard communications software package
that emulates a terminal to establish bidirectional communications with the receiver. Examples include
HyperTerminal or NovAtel Connect (a Graphic User Interface (GUI) program). All data is sent as raw 8-bit
binary or ASCII characters.
Section 4.2.2, Communicating with the Receiver Using NovAtel Connect
on page 54 for details.
If RS-232 operation is required, USERIO1 should be left floating or pulled low (GND) with a 4.7
kohm resistor. If RS-422 operation is required, USERIO1 should be pulled high (3.3 V) with a
4.7 kohm resistor. USERIO1 can be configured as an input or an output by an application. To
avoid possible damage, never connect the USERIO1 pin directly to 3.3 V or GND.
