ESP32 Thing Plus C not seeing GPS-RTK-SMA (ZED-F9P) on I2C / Qwic

GPS/GNSS Development Boards
1

Hello,

I’m having a little trouble getting the SparkFun Thing Plus ESP32 WROOM USB-C to talk to the GPS-RTK-SMA (ZED-F9P) breakout board. I have them connected via the I2C / Qwiic ports.

I’m trying to follow the GNSS Reference Station tutorial, Option 2 (https://learn.sparkfun.com/tutorials/ho … p-option-2). I have them connected exactly as shown in the tutorial photo (minus the LiPo battery to the Thing Plus, it’s going to be USB powered all the time).

When I run Example3_GetPosition.ino (Examples → SparkFun u-blox GNSS Arduino Lubrary → Example3_GetPosition) it stops at while (!Serial) and waits for ever, even if the serial monitor window is open. If I comment that out, it gets to myGNSS.begin and returns “u-blox GNSS not detected at default I2C address. Please check wiring. Freezing.” None of the examples in the ZED-F9P folder work either.

I’m using Arduino IDE 2.1.0, with the “SparkFun ESP32 Thing Plus C” board selected. I’ve tried both the SparkFin u-blox GNSS Arduino Library v2.2.22 and the SparkFun u-blox GNSS v3.0.12 both without any luck.

I’ve tried three different Qwiic cables from the SparkFun Qwiic cable kit (KIT-15081) – still no luck, even using the short 3" cable.

The Thing Plus seems to work, and I can run the WireScan example, which returns two devices (which is weird? I only have the ZED-F9P connected…)

The F9P responds normally when I plug it in via USB and check it with u-center – it’s getting good signal, and has a 3D fix mode. I’ve tried changing the F9P configuration, as shown in the “GPS-RTK2 Hookup Guide, Setting the ZED-F9P as a Correction Source” using section 3.5.8 of the u-blox Integration Manual (https://learn.sparkfun.com/tutorials/gp … -guide/all)…

What am I missing here? My wall is beginning to have a dent in it.

Thanks for any help/thoughts!

John

2

Hi John,

I wonder if you have accidentally disabled the UBX protocol on the I2C port? It needs to be enabled for both input and output for the library code examples to work correctly. Please try resetting your ZED back to the factory defaults using u-center, and give it another try:

https://github.com/sparkfun/SparkFun_u- … 1515038572

That post was about the NEO-M8U with a serial connection, but the procedure is the same for the ZED-F9P.

I hope this helps,

Paul

3

Under tool > board make sure it is the Sparkfun ESP32 Thing Plus C, not Sparkfun ESP32 Thing Plus. I had the same problem and this fixed it for me

4

This 100% worked. I don’t think I screwed up those settings, but apparently I did.

Paul, you’re some kind of witch/warlock or something :smiley:

Thank you so much!

John

5

I prefer Wizard… :ugeek:

Glad that’s working for you,

Paul