Weird/NonFunctional GPS indications on new T-beam running 1.2.45


I recently got two 868/915 T-Beams and have installed 1.2.45 Firmware on both of them. The first one is working perfectly from what I can see, but the second one still hasn’t shown a GPS fix in several hours. When I first flashed the problem board it gave me the #5 critical error, which pertains to the GPS module (these have 6M chips). I reset the board, and re-flashed it earlier and this message hasn’t appeared again, but has never indicated anything but “NoSats” or “NoGPSLock”.

My first question: How would I know if the chip is outright bad vs just not seeing a signal? The Critical Error#5 on my initial startup has me paranoid about the functionality of the NEO-6M on my board.

Second question: I’ve seen some users on here posting verbose output from the ESP32 that contains a lot of information about various chips like the AXP and the GPS module. I’ve also seen users uploading code directly to the ESP32 to control the NEO-6M and AXP configuration. What I can’t find is the step-by-step on how this is done. What is the best resource for learning how to get serial output from my TBeam and to configure the GPS chip?

Thanks! I’m very excited to be a part of this community :slight_smile:

Also had a similar problem recently, I could see the red light flashing on the GPS (which shows it has a lock) but every sketch I tried couldn’t get any serial output from the GPS.

It was fixed by running the second of these scripts: GitHub - eriktheV-king/TTGO_T-beam_GPS-reset: Reset U-blox NEO GPS devices on TTGO T-beam T22- V1.0 and 1.1 back to factory settings

It looks like sometimes the GPS on these get’s mis-configured and the NMEA output becomes disabled.

(You might want to take a look at those scripts to help you understand how the AXP and GPS is configured too!)

Thanks for the reply Siftah!

The chip is apparently fine as it ended up acquiring a fix after a few hours. I will still probably look into those scripts to learn more about the board as you suggested. Thank you for sharing those!

You can connect to your T-Beam via USB with any serial terminal at 921600 baud to take a look at the serial debug messages :wink:
Or you can use the official python command line interface with the --noproto option:

I can tell you that the GPS is crappy with the NEO-6M in general.

If you ever make a purchase in the future, I’d highly advise the SX1262 boards with the NEO-8M GPS chip and also buy a GPS antenna to go with it.

I’ve asked around here to allow the GPS to be supplied via the phone if connected, let’s see if that change is implemented.