I have a L76K, and while it is generally working, its reliability and behaviour is making it unsuitable for the application I am building. The L76K is part of the Lily T-Beam Supreme s3 version 3 device.
“The L76K firmware on my device is dated March 2020 (URANUS5,V5.3.0.0) and responds to PMTK commands. Is this expected? Are PMTK commands officially supported alongside PCAS commands?”
“Is there a newer firmware version available for the L76K? If so, what improvements/changes does it include?” Where could I get a copy?
Operational Questions:
“When using 1Hz position updates and logging to SD card, I sometimes see a pattern of 20 minutes good operation followed by 10 minutes of lock loss. Is this a known behavior?”
“Are there recommended power management or configuration settings to optimize stability during continuous operation?”
Technical Clarification:
“The protocol specification (v1.1) only documents PCAS commands but not PMTK. Is there additional documentation covering PMTK command support?”
“What is the recommended initialization sequence for the L76K when used in mobile tracking applications?”
L76K only supports PCAS commands, not PMTK commands.
L76K is a ROM version and does not support version upgrades.
You need to check whether the lock-out problem is caused by unstable power supply or bad environment. If you want good positioning performance, you need to ensure that the module environment is tested in an open and interference-free environment.
I find it interesting: my code is using PMTK commands and is working, at least it writes out my GPX file as I expect, even though the device does not support PMTK?
Power is provided by a fully charged Samsung 18650 battery…
I have tested the device in quite a few situations mostly in open countryside even with very few trees. My code (such as it is) reports 12 satellites with HDOP of 0.8 to 1.1 so I think the ‘quality’ of the fix is fine. The locking up is a repeatable issue, so I doubt this is an environmental problem.
Do you think my device is defective? My device is a Lilygo T-Beam Supreme s3 version 3.0. Can you suggest or speculate what could case a bottleneck or hang every 20mins based on my experience.
Is there a testing application that I could use to test the device?
Is there any documentation available, so that I can convert my code to PCAS.
Hi @Wellco
This version is too old.
If you want to get a better positioning effect, you can try to use an active antenna. Or you can choose our other GNSS modules.
I purchased this from Lilygo earlier this year. It comes on their T-Beam S3 Supreme V3. How come it’s too old. I have no way of changing it since it would require professional level soldering skills. Pretty disappointing you’re saying its too old… Should I go back to lily and ask for a newer model?