User Manual

EB-5662RE

High Performance GPS Engine Board

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NMEA Input Command

A). Set Serial Port ID: 100 Set PORTA parameters and protocol

This command message is used to set the protocol (SiRF Binary, NMEA, or USER1) and/or the

communication parameters (baud, data bits, stop bits, parity). Generally, this command would be

used to switch the module back to SiRF Binary protocol mode where a more extensive command

message set is available. For example, to change navigation parameters. When a valid message

is received, the parameters will be stored in battery backed SRAM and then the receiver will

restart using the saved parameters.

Format:

$PSRF100,<protocol>,<baud>,<DataBits>,<StopBits>,<Parity>*CKSUM<CR><LF>

0=SiRF Binary, 1=NMEA, 4=USER1

<baud>

1200, 2400, 4800, 9600, 19200, 38400

8,7. Note that SiRF protocol is only valid f8 Data bits

0,1

0=None, 1=Odd, 2=Even

Example 1: Switch to SiRF Binary protocol at 9600,8,N,1

$PSRF100,0,9600,8,1,0*0C<CR><LF>

Example 2: Switch to User1 protocol at 38400,8,N,1

$PSRF100,4,38400,8,1,0*38<CR><LF>

**Checksum Field: The absolute value calculated by exclusive-OR the 8 data bits of each

character in the Sentence, between, but excluding “$” and “*”. The hexadecimal value of the most

significant and least significant 4 bits of the result are converted to two ASCII characters (0-9, A-F)

for transmission. The most significant character is transmitted first.

**<CR><LF> : Hex 0D 0A

B). Navigation lnitialization ID：101 Parameters required for start

This command is used to initialize the module for a warm start, by providing current position （in X,

Y, Z coordinates）,clock offset, and time. This enables the receiver to search for the correct

satellite signals at the correct signal parameters. Correct initialization parameters will enable the

receiver to acquire signals more quickly, and thus, produce a faster navigational solution.

When a valid Navigation Initialization command is received, the receiver will restart using the input

parameters as a basis for satellite selection and acquisition.