Cannot issue NMEA commands to the Teseo on STEVAL-STRKT01 over good CN503 UART link.

[theo kretzschmar-schuldorff]

Hello ST,

I’m attempting to integrate the STEVAL-STRKT01 into my system.

I need to issue NMEA commands to the Teseo .

I’m connected into the UART over CN503 (TX,RX,GND only) and I can see the serial chatter.

For example, I want to Stop the STAGPS engine with $PSTMSTAGPSONOFF,0*4A

This, and all other commands I am testing, are getting no responses. Am I doing something wrong, or can I not send NMEA to the Teseo on this Evaluation board?

Attached a screenshot of one of the billion ways I’ve tried this. Any help much appreciated!

[Tesla DeLorean]

How about a simpler firmware version query?

Any inbound commands work?

TESEO-SUITE ?

[theo kretzschmar-schuldorff]

Its hard to tell if my NMEA commands are triggering any response at all, the UART is sporadically spooling out NMEA messages info without being prompted. Including versioning info.

I suspect the STEVAL-STRKT01 board is continuously interrogating the Teseo and has exclusive use?

I set up the Teseo-suite, image attached, but still couldn't get it to accept PSTMSTAGPSONOFF..

[Tesla DeLorean]

Would check you're not getting some conflicting signals on the GPS's RX pin from the LoRa MCU, or other sources/connections.

https://www.st.com/resource/en/schematic_pack/steval-strkt01_schematic.pdf

[theo kretzschmar-schuldorff]

Thanks for your analysis - that's almost certainly right. The Lora module does seem to be obstructing my commands.

Do you think I can hope to interrupt (temporarily) this UART connection between LoRa & LIV3 without damaging the hardware? I don't see an obvious move here..

[Tesla DeLorean]

I'd probably start by removing resistor/zero-ohm R204, so you can connect via TP202