MicroPython Forum (Archive)

New to micropython and loving it so far.

I come from a C world for embedded work and have been noodling in Python for about a year for desktop utilities. As I have made a few projects in microPython on ESP32 (SparkFun ESP32 Thing) - I have discovered that I have no idea how to best learn and approach low-ish debugging that crashes the system.

Initially, I was going to post something about the specific issue I am having, but then I decided it would be more helpful to learn how to figure it out on my own. The crashy code at unpredictable times gives me this.... It happens at various places in the code, and totally unpredictable as far as I can tell. Using interrupts and timers along with MQQT module called umqttsimple. Trying to figure out how to best understand the exception output and perhaps some reading or video resources to better educate myself on the lower levels of micropython debugging.

Hoping to eventually use this platform for a commercial product if I can get the stability I have grown accustomed to when designing firmware with C.

Looking forward to any suggestions for good learning resources.

Take a look at https://github.com/tve/esp32-backtrace, it has helped me track down a few issues with my code.

As a general point I have never attempted to debug those crash traces as they indicate that the MicroPython interpreter or the FreeRTOS runtime have crashed. If you can produce a minimal Python script which exhibits the crash, you have found a bug which can be reported on GitHub. Of course you are free to pursue this further, find a fix, and raise a PR against the firmware.

I think it's worth bearing in mind a few limitations. One is that ESP32's do occasionally reboot. SPIRAM versions are also known to be unstable. That said, non-SPIRAM chips should run for days between reboots, and should not crash. A repeated crash does suggest a problem, but it could be hardware or power supply issues. Standard Python code should not crash.

Finally the official MQTT versions have serious limitations discussed here.

Interesting notes.....

I think I will be looking closely at the power first. Power electronics and high-speed PDN design is one of my specialties - easy to take a look. The board I am using is a SparkFun Thing which does not appear to make any major efforts in clean power.

Also looking closer at the MQTT limitations linked.

Perhaps just doing WiFi tests alone, push-button tests alone......and then add the MQTT to see if it only crashes with MQTT running.

Old school - code it and try it method.

Typical power problems arise because ESP32 current consumption can rise to about 0.5A which can cause voltage drops in USB leads. Another cause are lousy wall-warts designed for phone charging rather than continuous running.

pythoncoder wrote: ↑

Tue Apr 06, 2021 6:38 am

Typical power problems arise because ESP32 current consumption can rise to about 0.5A which can cause voltage drops in USB leads. Another cause are lousy wall-warts designed for phone charging rather than continuous running.

(To anyone reading this post ):

Are there any specific USB cables and/or power supplies that are "known good" in this regard?

I've youtubed this and there's general advice, but links to buy high quality items are like gold for possible problems like this.

I am a big fan of pragmatically using things others know are of quality.

Official Raspberry Pi power supplies are designed for continuous use and have plenty of capacity.