I purchased the RTK2 board to output NMEA strings to an agriculture display. My end all goal is to utilize the UART2 port for the RTCM correction data via a bluetooth mate (which is working) and then output the corrected NMEA string from UART1 tx/miso pin which will be connected to my display. The NMEA output from UART1 tx/miso pin is not working appropriately and I can’t seem to figure it out. I’m kind learning on the fly here, so I apologize if there is something simple I’m missing but below are the troubleshooting steps I have performed and what I’ve learned.
I have downloaded a NMEA capture program to my computer to see what data is coming out of the Tx/miso pin on UART1. When I connect it my capture program says “Error: No line breaks in data stream.” I’m not exactly sure what this means but assume it’s something with the format of the NMEA data.
As I have the bluetooth mate attached to UART2 for my RTCM correction data I changed my port settings to output NMEA data from this port and connected my computer to the bluetooth mate. Through my capture program I was able to successfully read the NMEA strings coming out of the UART2 port via the bluetooth mate.
The interesting piece to me is if I connect that same UART2 tx2 pin that is feeding my bluetooth mate directly to my capture program I get the same error message as I did when connecting directly to my UART1 tx/miso pin.
Is the bluetooth mate doing some sort of conversion to the data? Is there a special setting required when making direct connections?
Hi Eric,
A quick suggestion would be to use the U-Center Software to configure the UART1 port. My guess is the NMEA reading software you are using needs to have some line ending setting enabled for it to properly interpret the data. I would recommend reading our [Getting Started With U-Center tutorial for help installing and learning the basics of U-Center.
Once you have configured the UART1 port, try reading the NMEA sentences again over that port. As an alternative, you should have no issue using the USB port for reading NMEA sentences while also using UART2 for RTCM correction data.
I hope this helps explain the issue and gets you pointed in the right direction. If you continue to have problems with the serial data from your ZED-F9P over UART1, please reply to this message and we would be happy to help as much as we can.](https://learn.sparkfun.com/tutorials/getting-started-with-u-center)
Thanks for the quick reply. I am using U center to configure the ports for the appropriate input/output. Does the Bluetooth mate do any conversion of the NMEA strings? It just seems odd that it works via the Bluetooth mate but not when directly connecting to the Tx2 pin. Also, is the tx/miso pin the correct UART1 pin to connect to for my output?
Hi again Eric,
Interesting. What are you using to convert from Serial TTL on UART1 to USB and what are your connections for that UART? For your questions:
-
The Bluetooth Mate is really only acting as a wireless replacement for a USB to Serial bridge like our [FTDI Basic Breakouts..
-
You are correct, TX/MISO is the TX out from UART1. So long as the DSEL jumper is in its default, open position, those pins should act as the Host UART.](https://www.sparkfun.com/products/9873)
Mark,
I am utilizing a simple serial to USB adapter that I purchased a while ago on amazon to read the data. I have made a quick cable that connects the TX pin to a male DB9 that connects directly to my serial (female) to USB cable. As I am only sending data out of the board I did not think it would be necessary to connect any other pins but I could be wrong. The jumper on the back is also in its default state as you have mentioned.
I’m using the Capture tool found at the following link from Lefebure.
http://lefebure.com/software/gpsutils/
I appreciate the help as I am learning here.
Eric
Hi Eric,
Sorry for the delay here. I thought I posted this reply but I guess not. For your connection to UART1, I would recommend connecting at least UART1-TX to Adapter-RX and Ground to Ground. Otherwise, the data signals on that UART have no reference for low/ground. You may also want to connect UART1-RX to Adapter-TX if adding the ground connection does not work. Also, make sure the logic for those serial connections is running at 3.3V or else you risk damaging those pins.