If you need to avoid clock drift then you really need to use an external 32K crystal in your circuit. There are some dedicated APIs for this....

I would like to communicate with an external web server from the ESP32. However, we need to be able to do this via an external cellular modem that provides a raw socket interface (we already have a network stack that provides this). It looks like the HttpClient library ( https://docs.espressif.com/p...

I had a search through the IDF source code (https://github.com/espressif/esp-idf) and couldn't find source for these error messages. I'm not sure if they are emitted from the ROM or included in the IDF as binaries but it's pretty frustrating. There seem to be quite a lot of google hits for wifi: sta...

Thanks @boarchuz. The ULP is a good idea. I agree it's unlikely but in a previous life we had a significant issue with a similar problem (albeit high unit volumes and exacerbated by lack of brownout protection) and the current product is intended to work for 5-10 years in the field without any manua...

@chegewara Perhaps I haven't explained clearly enough.... Although it's very unlikely, the CPU program counter can get corrupted. One reason for this is supply brownout though this is protected against on the ESP and most modern CPUs. There are plenty of other reasons though and one of the most like...

@chegewara. That doesn't protect against the kinds of errors I'm talking about where the code is in such an error state (e.g. from a corrupted PC return address on the stack) that it is calling the raw API with a random value. @WiFive Thanks - that sounds interesting. Is there an API to control this...

According to the documentation https://docs.espressif.com/projects/esp-idf/en/latest/api-reference/system/sleep_modes.html esp_sleep_enable_timer_wakeup accepts a 64 bit value which is the number of microseconds. The maximum value of this is rather high - hundreds of thousands of years! Since my app...

Perfect, RTC_NOINIT_ATTR is exactly what I was looking for - thanks!

My application is deeply embedded and so I have a 'fault' mechanism that performs esp_restart if unusual conditions are detected. I would like to persist the reason for the fault (e.g. "too many connection attempts") through the restart so that it can be written to the flash filing system then uploa...

*Bump* Any progress on this Espressif? We'd really love to be able to transmit a beacon every few seconds while averaging < 100uA but this just isn't possible at the moment.