Stars Navigation Technologies MTI-1, User Manual

8

2.2  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> 

<protocol> 

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

<baud>   

        1200, 2400, 4800, 9600, 19200, 38400 

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

<StopBits> 

         0,1 

<Parity>  

         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> 

Name Example Units

Description

Message ID 

$GPVTG 

VTG protocol header 

Course 309.62 

degrees 

Measured 

heading 

Reference T 

True 

Course  

degrees 

Measured 

heading 

Reference  

M 

Magnetic 

Speed 

0.13 

knots 

Measured horizontal speed 

Units N 

Knots 

Speed 

0.2 

Km/hr 

Measured horizontal speed 

Units 

K 

Kilometers per hour 

Checksum *6E 

<CR><LF> 

End of message termination