GPS module

[ed181]

hi,
I'm trying to understand how this GPS module works. Basically i want to know how TXD and RXD pins function. If i wanted to interface the module with a PIC how do i get the relevant information from the module. For example if i wanted to obtain information reguarding the speed of the module would i continously sample the output pin and wait for $GPTG to appear, or do i need to send some sort of input command to the module?
http://www.rfsolutions.co.uk/acatalog/DS-GPS622R-2.pdf

cheers,
ed.

 

[(*steve*)]

Read the table on page 5

NMEA is proprietry, and they want $25 for a copy of the standard, but this is a good summary.

 

[ed181]

hi,
would you mind answering another question for me. I want to know what the RX pin does on the module. Do i need to send the recieved data back, or a command to get the desired sentance from TX. sorry if this sounds silly i'm very new to this.

 

[(*steve*)]

You certainly don't need to send it the transmitted data back again.

Whether or not you have to send it something to make it start giving you positions is something I don't know (and I'm not going to read the spec to find out). I would suggest that there are probably commands you *can* send, since there are many different forat outputs.

I would connect the thing to a serial port on a laptop and see what it does. You may need to take it for a bit of a walk outside too.

 

[ed181]

ok, thanks. I hadn't purchased the module, i just want to be sure i could use it before i bought it. i think i understand what i'm doing now. cheers

 

[aishiqi]

turn on it. you need not send any commands. it will send you GPS data per second by TXD.you can use computer to get the data.a USB-TTL serial converter will be needed.i have made a GPS clock based on it.

 

[aishiqi]

data form like this
$GPRMC,062500.000,A,3853.4663,N,11527.4923,E,0.00,,161206,,,A*75
$GPGGA,062501.000,3853.4663,N,11527.4923,E,1,06,1.4,74.5,M,-10.3,M,,0000*40
$GPGSA,A,3,08,17,20,28,11,04,,,,,,,2.3,1.4,1.9*3C