Help with eTrex GPS interfacing to BS2 revG

rocketman889

Hello,

I'm trying to interface my Garmin eTrex to my BS2 revG. All I am trying to do is read in any data, and display it. I tried other code like the Easy_GPS.bs that was posted on another thread, but I keep receiving a No GPS error. I take this is a timeout error built into the SERIN command.
Hooking the GPS up to the serial port and running hyper-terminal, I do receive data. Right now, I have a 22k ohm resistor connecting the Data Out on the GPS to Pin 0 on the BOE. Is there something that I am not getting? or something I should look for about the timeout?

Please help,

Mike

Phil Pilgrim (PhiPi)

The data coming from the eTrex GPS is inverted. Are you using inverted mode (Baudmode = 16572) with SERIN?

-Phil

rocketman889

Hey Phil,

Yes, I believe I am using the inverted mode with the SERIN command. I will try again tonight to confirm this and let you know.

Thanks,
Mike

steve_b

Did you connect the ground from the BS2 to the GPS?
You need a common ground as well!

Transmit data line from the GPS should be connect to your receive pin on your Stamp. It's easy to confuse the TxD and RxD lines.

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
·

Steve

"Inside each and every one of us is our one, true authentic swing. Something we was born with. Something that's ours and ours alone. Something that can't be learned... something that's got to be remembered."

rocketman889

I checked the Baud mode. I'm running two different sets of code. The first reads data from the GPS using NMEA at 4800 baud. With this, I have the baud mode set to 16572. The other code uses Garmin Text Out at 2400 baud, and the baud mode was set to 16780. I connected Pin 5 to ground and I tried both Pins 2 and 3 to Pin 5 on my board. I believe that Pin 2 on the Garmin connector is data out from the GPS.

I have attached the original file of the Easy_GPS.bs that I found on another post.

Thanks,

Mike

steve_b

You say you're going from the GPS pin 2 or 3 to pin5 on your BOE....but in your code you show that you are using pin0.

Are you getting anything in the debug window? Like "...No GPS" as should happen when you don't get a valid data stream!?

IF you are indoors you may not get the data stream you are after as well....so you should get the NO GPS reply in your debug window.

Have you set your Etrex to the NMEA output?

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
<FONT>Steve



What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
Lee Travino after the second time being hit by lightning!

rocketman889

Hey Steve,

Yea, the code I posted was the original code. I connected the input to the right pin, or modified the code. I do get the "..No GPS" in the debug window. I tried changing the output to NMEA output as well as text out. Could it be that the BS2 revG might not be up to the challange? But then again I heard of some other people overcoming the speed issues....


Thanks for your support,

Mike

steve_b

Investigate the string variables.
I'm on the road right now and don't have access to m'files, but it should be in the PBasic help file...just try and read in ANY data with the STR command. Then output it. If you have readable numbers with comma delimiters, then your data is coming in....just may need to tweak things to get it running smoothly!

▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔▔
<FONT>Steve



What's the best thing to do in a lightning storm? "take a one iron out the bag and hold it straight up above your head, even God cant hit a one iron!"
Lee Travino after the second time being hit by lightning!