Data Sheet

UM7 DATASHEET
Rev. 1.6 – Released 1/10/2016
19
Depending on how it is configured, the UM7 can transmit either binary packets for efficiency,
NMEA-style ASCII packets for easy readability, or a combination of both. NMEA packets can be
transmitted by the UM7 at rates of up to 100 Hz. Binary packets can be transmitted at rates of
up to 255 Hz.
The communication architecture of the UM7 allows the user to select both what data is
transmitted, and at what rates. Each packet type can be configured to transmit at its own
unique rate. For example, the UM7 might be configured to transmit a health packet once a
second, a position packet 10 times per second, and attitude packets 250 times per second.
Alternatively, the user can poll the sensor to read any subset of its data registers at any time.
This flexible communication architecture allows the user to take full advantage of the limited
bandwidth available on the UART.
If the UM7 is configured to transmit more information than can fit on the serial bus, a
COM_OVERFLOW flag will be set in the device’s health register.
To configure the UM7’s transmission settings and other settings, binary packets must be sent to
change the settings in a variety of configuration registers, described later in this document.
Settings can be changed manually by constructing and sending the appropriate packets, or
more easily by using the CHR Serial Interface software. Configuration settings can be saved to
device FLASH so that they persist when power is removed.
Packet transmission rates are configured using registers CREG_COM_RATES1 through
CREG_COM_RATES7 (See the Configuration Registers section for more details about
configuration registers).
The serial baud rate can be configured by writing to the CREG_COM_SETTINGS register.
For more details about the register architecture on the UM7, see the Register Overview section.
For specific details about how to write to and read from registers, see the Binary Packet
Structure section, or refer to the UM7 User’s Guide, available at www.redshiftlabs.com.au, to
learn to use the Serial Interface software.
NMEA PACKETS
NMEA packets provide data in human-readable, comma-separated messages over the serial
port. These packets are easily interpreted by human operators and, depending on the context,