RTK Surveyor no NMEA over data port

SPARK-X
1

I would like to output NMEA from the data port on an RTK Surveyor V17 I recently purchased, but I am only getting garbled records.

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I have played with the various switches available on the board as described [here. I chose not to mess with the port in the back as it didn’t seem relevant, but as described in [this post it was not clear how the switch in the back fit into the scheme. It does appear there is a [old branch for the V17 in the GitHub hardware repo.

To try to get the expected NMEA output in Putty I have:

  1. Updated the firmware on both the ESP32 microcontroller (v3.2) and the u-blox ZED-F9P (1.32)

  2. Changed baud rates on the data port, both through BlueTooth and Wifi.

  3. Changed baud rates on the in Putty, which is how I attempting to view the serial NMEA records.

  4. Reset to factory defaults.

  5. I have adjusted the messages and message rates and ensured there is not a buffer overrun as described [here.

At this point I am fairly confident that I have the switches correctly,and I believe the ublox is outputting NMEA correctly as I can see NMEA records over BlueTooth when the switches are set accordingly. I have connected serial NMEA into putty on my current machine / configuration previously, so I don’t think I am missing anything on the PC end.

Any ideas / suggestions are welcome.](https://docs.sparkfun.com/SparkFun_RTK_Firmware/configure_ports/#:~:text=for%20custom%20applications.-,Data%20Port,-By%20default%2C%20the)](GitHub - sparkfun/SparkFun_RTK_Surveyor at release_candidate)](RTK Surveyor: no output on Bluetooth serial or data UART - SparkFun Electronics Forum)](https://docs.sparkfun.com/SparkFun_RTK_Firmware/configure_ports/#:~:text=a%20popped%20balloon.-,Surveyor%20Data%20Port,-By%20default%2C%20the)

2

Great detective work!

The general pitfalls are:

  • Getting the baud rate correct on both devices (host and RTK)

  • Avoid connecting 3.3V from the Host to the RTK. You really just need two wires: TX and GND from the RTK. Don’t back feed power to the RTK.

Are you able to see NMEA data over Bluetooth? The DATA port shares the connection with the ZED so if you can see it on SW Maps you should be able to see it on a host terminal.

3

sparky:
Are you able to see NMEA data over Bluetooth?

Yes, Bluetooth works. I primarily have been looking at the output in the Serial Bluetooth Terminal app, but things work in SW Maps as well.

sparky:
The general pitfalls are:

  • Getting the baud rate correct on both devices (host and RTK)

  • Avoid connecting 3.3V from the Host to the RTK. You really just need two wires: TX and GND from the RTK. Don’t back feed power to the RTK.

I have tied off the 3.3V (Red) to avoid attaching by mistake and have only been using GND and TX.

I will continue adjusting the baud rate, but I feel like I have tried just about every setting I can from both (RTK Surveyor, Putty) sides (with the correct switch flipped in the RTK surveyor to redirect from data port to Bluetooth). If there are any other ways to troubleshoot I would be happy to try them. Thanks for the help!

4

Sorry, I think I’ve given you some bad info. It’s been a while since I’ve used the DATA port on a Surveyor. Please have a look at the schematic:

https://cdn.sparkfun.com/assets/learn_t … or-v13.pdf

Additionally, the Advanced Features of the Hookup Guide: https://learn.sparkfun.com/tutorials/sp … d-features

I believe you need to set the Serial NMEA Connection switch to the lower position (labeled ‘Ext Cntr’) to connect the ZED’s output to the DATA port.

We replaced this with a digital MUX on all the later RTK products. I forgot that switch was still in the serial path. Sorry!