Issue setting Baud Rate on Ultimate GPS Hat for RPi

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cryptos9099
 
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Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by cryptos9099 »

Hello, I seem to have a problem setting the Baud Rate of the HAT to 38400 for 10 Hz Update Rate use. The HAT was working around 12 hours ago at 38400/10Hz but now it seems to not run at those settings and not be responding to PMTK commands as of now. I've read other people having similar issues and followed some of the more likely solutions (resolder, pull power and battery) and tried to run it at 9600 Baud but the HAT seemed to be stuck at 38400 and was not accepting PMTK commands. After several tries, now the HAT has somehow been set to 9600 and still doesn't accept PMTK commands.

I am at a loss of what to do to resolve the issue.

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adafruit_support_rick
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by adafruit_support_rick »

please post some pictures of both sides of the HAT

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cryptos9099
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by cryptos9099 »

https://imgur.com/a/8TGDw

Here are the images as requested.

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adafruit_support_rick
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by adafruit_support_rick »

That all looks OK.

How are you sending the PMTK commands?

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cryptos9099
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by cryptos9099 »

Through an echo directed at /dev/ttyAMA0

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adafruit_support_rick
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by adafruit_support_rick »

Hmmm... Don't really know what to suggest. You're sure you're using the correct checksums on the PMTK commands?
This is a handy checksum calculator:
http://www.hhhh.org/wiml/proj/nmeaxor.html

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cryptos9099
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by cryptos9099 »

I have been using that very calculator for generating checksums.

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adafruit_support_rick
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by adafruit_support_rick »

This is strange. It must be accepting PMTK commands at least occasionally, since you've been able to change baud rates.

Is it still doing 10Hz, or has that been changed back to 1Hz? Really, the only thing it can be is a bad connection on the HAT's RX line. Can you try re-heating that joint again?

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cryptos9099
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by cryptos9099 »

It is doing 1Hz right now. I've reheated and doubled the solder and still the same behavior.

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adafruit_support_rick
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by adafruit_support_rick »

We can try replacing the HAT, although I'm not sure that will help.
Please email [email protected] with a link to this thread for a replacement

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lkovacs
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by lkovacs »

Hello,

I have the same problem, but I can't change the default parameters at all (never).

I resoldered the connections, and checked the +5V, gnd, RX and TX pins with a volt meter and the connections seems to be ok.
Resoldering doesn't solved my problem.
I have an ultimate gps v3 also, which works fine.

I sending the commands via echo from ssh. Gpsmon, cgps working fine, but I can't change the baud rate and the nmea freq at all.

the commands what I use:

echo -e '$PMTK220,100*2F\r\n' >/dev/ttyAMA0
echo -e '$PMTK251,38400*27\r\n' >/dev/ttyAMA0

cat /dev/ttyAMA0 correctly lis the nmea sentences.

Any help would be appreciated!

Thanks,
Laszlo

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adafruit2
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by adafruit2 »

huh you know we've never used command line to set up the GPS HAT - we do test both RX & TX so its *not* likely the hardware
perhaps minicom or a small python script would work for testing?

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lkovacs
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by lkovacs »

Yes, if you could post a python code, I can try it out. But, if you read back in this topic, the topic opener also uses echo commands.
The command line commands works fine with this board: https://learn.adafruit.com/adafruit-ult ... s/overview.
I also uses UART with ultimate board.

Please note: " Gpsmon, cgps working fine", so RX is OK, so something is wrong with accepting PMTK commands.

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adafruit2
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by adafruit2 »

we dont have any example code handy - you can check using an oscilloscope to make sure signal is making it out to the GPS
you can also try minicom, that is easier than writing code

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lkovacs
 
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Re: Issue setting Baud Rate on Ultimate GPS Hat for RPi

Post by lkovacs »

Could you instruct me how could I test my board with minicom?
I can't have oscilloscope, so I can't test with oscilloscope.

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