Rainbow Electronics GE863-GPS low power - Manual (Page 115)

GE863-GPS Software User Guide
1vv0300724 Rev. 3 - 05/07/07
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*CKSUM
CKSUM is a two-hex character checksum as defined in the NMEA specification, NMEA-0183
Standard For Interfacing Marine Electronic Devices. Checksum consists of a binary exclusive OR the
lower 7 bits of each character after the “$” and before the “*” symbols. The resulting 7-bit binary
number is displayed as the ASCII equivalent of two hexadecimal characters representing the contents
of the checksum. Use of checksums is required on all input messages.
Each message is terminated using Carriage Return (CR) Line Feed (LF) which is \r\n which is hex 0D
0A. Because \r\n are not printable ASCII characters, they are omitted from the example strings, but
must be sent to terminate the message and cause the receiver to process that input message.
NOTE: All fields in the SIRF proprietary NMEA messages are required, none are optional. All
NMEA messages are comma delimited.
5.7.2 Message 100 – Set Serial Port
This command message is used to set the protocol the communication parameters (Baud, data bits,
stop bits, and parity). When a valid message is received, the parameters are stored in battery-backed
SRAM and the Receiver restarts using the saved parameters.
The command has the following syntax:
$PSRF100,,,,StopBits>,*
Example: setting the serial port to 9600 Baud, 8, n, 1
$PSRF100,1,9600,8,1,0*0D
The following table describes the command fields:
Name Example Unit Description
Message ID $PSRF100 PSRF100 protocol header
Protocol 1 1=NMEA
Baud 9600 1200, 2400, 4800, 9600, 19200, 38400,
57600, and 115200
DataBits 8 8,7
StopBits 1 0,1
Parity 0 0=None, 1=Odd, 2=E ven
Checksum *0D
End of message termination