Jupiter-T GPSDO Communication

[davorin]

Have now all components together to build a GPSDO 10MHz reference oscillator..

When I power up the GPS module I receive the standard 0xFF, 0x81 start sequence in the reply...

Though when I try to communicate with it there seems to be no reply at all....

For example the command "@@Cj" should return model, version and serial number...but doesn nothing...

[davorin]

Found some documentation and examples here....but still no luck with it....for example just how to find out if the GPS has a lock...

http://www.casde.iitb.ac.in/IMSL/motion/gps/

Connecting my HP5335A display for the first 5 - 10 minutes a value of 10000.360 Hz...then goes down to 10000.177 Hz...which is reproducible when power-cycling the Jupiter-T GPS module...

[davorin]

As per example in the Word document in the link above....getting the pinning status should be possible with:

Code: [Select]

echo -ne '\xFF\x81\xF4\x03\x00\x00\x00\x48\x0D\x32' > /dev/ttyUSB0

Still no output....only during power-up...

[jpb]

It sounds as if the Jupiter is not receiving your signals - perhaps there is a fault on pin J1-9. You may even have a faulty cable - have you double checked it with a DMM for continuity?

[davorin]

I see the signal going to pin 9...

Also..happens with both of my TU60-D001 modules...

Bitrate is also correct when sending...just checked with a simple '\xAA' > /dev/ttyUSB0 and my DSO...

[davorin]

Hmm...should work with a regular USB2TTL serial adapter, right?

Not that the Jupiter expects RXD to be inverted.....

[Andy Watson]

Not that the Jupiter expects RXD to be inverted.....

Are you sure about that? The jupiter GPS that I've used required its serial output converting to RS232 level (including inversion). Also, check the mode that it boots-up in. I think it defaults to the NMEA message mode.

[davorin]

They default to binary mode...as it sends after reset this message with the regular 0xFF81 flag:

Code: [Select]

\0xff\0x81\0x9c\0x04\0x01\0x00\0x00\0x00dy\0x00\0x00\0x00\0x00

[davorin]

Just stumbled upon this thread:

http://en.it-usenet.org/thread/16759/1388/

And tried myself with the Motorola WinOncore 12 software, and it is indeed sending information back when asked for the receiver id:


Also it sends data continuously when opening the command monitor...

[davorin]

Some step forward (o;

Sending this:

Code: [Select]

echo -ne '@@Cj)\x0D\x0A' > /dev/ttyUSB0

returns the module information:

Code: [Select]

@@Cj
COPYRIGHT 1995-2004 NAVMAN LTD.  
SFTW P/N # 0000           
SOFTWARE VER # 93         
SOFTWARE REV # 07         
SOFTWARE DATE  01/16/2004 
MODEL #    R01            
HDWR P/N # TU60-D125      
SERIAL #   407132508      
MANUFACTUR DATE 401//12070
OPTIONS LIST    5843      

Sending:

Code: [Select]

echo -ne '@@Ea\x01\x25\x0D\x0A' > /dev/ttyUSB0

initiates the sending of the status/position information every 1 second...

[davorin]

Seems to be plain Motorola binary format it accepts after power-on:

https://www.febo.com/pages/hardware/VPCommands.pdf