PDA

View Full Version : BASIC Stamp 2 & Parallax GPS Receiver Module



Ray Hill
12-03-2006, 09:05 AM
Hi,

I'm new to the forum, fairly experienced with the BASIC Stamp controllers & trying the Parallax GPS Rcvr Mod.

The receiver module's led indicates that it has aquired a minimum of 3 sats. However, I can't seem to get a valid response to the GetInfo or the GetValid commands. I'm using the example code GPSDemoV1.1.BS2. With each loop I get different responses to the GetInfo and GetValid commands. In other words, with each program loop, I get a different value for the HW Version, FW Version and the response to the GetValid command is never '0' or '1'.

I'm using about a 100' cat5 cable to get the receiver outside. But I've also tried getting valid responses to just GetInfo & GetValid with the receiver on the same breadboard with the BS2.

It would almost seem that the Baud is set wrong. I've tried 188 for the BS2 and even switched controllers and tried Baud = 500 with the BS2p40.

Any help, will be appreciated.

Ray

Chris Savage
12-04-2006, 08:40 AM
Ray,

What are you getting for the HW Version and the FW Version? Can you measure the level on the /RAW pin?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support

Ray Hill
12-04-2006, 12:46 PM
Chris,

I get what appears to be random values for HW, FW and for the value returned by the GetValid command. For instance:

Program Pass (Loop) 1 2 3 4 5 6
HW Version 2.4 2.C 6.9 6.2 8.9 2.4
SW Version 4.7 4.C 3.6 6.2 8.9 4.7
valid 36 162 36 147

If I'm reading my scope correctly, I'm getting about a 300mV signal on the RAW pin.

Ray

Chris Savage
12-04-2006, 11:14 PM
Ray,

It seems the internal pull-up on the /RAW line isn’t functioning and so you’re getting raw NMEA data instead of the smart data you should be getting. You can try to confirm this by putting a resistor from the /RAW line to VDD. The value could be anywhere from 4.7K through 10K. In any event you should contact Tech Support for a replacement. Take care.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support

Ray Hill
12-05-2006, 02:55 AM
Chris,

That's it!. I looked for some of the NMEA strings like "$GPGS" and I'm seeing them frequently. I should have thought of it.

I'll get with Tech Support.

Thanks for your help!

Ray

Chris Savage
12-05-2006, 05:59 AM
Ray,

Check your e-mail…We have you covered. Take care.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
Chris Savage
Parallax Tech Support