I use the same function, similar to one in ESP example esp_battery_reading_single to measure the ESP board battery voltage. It resides in a separate component. I call this function directly from my project main() function and from a second separate component C file function, called from main(). If c...

Thank you. You were right. I had a subtle small bug in allocating memory for the structure in my main.c code.
Now everything with ESP32 deep sleep works as expected.

Yes, I missed to mention that I have defined two RTC_DATA_ATTR structures in two separate source files: main.c and the second with strange behavior, in a separate .c file. I observed earlier that the sequence of placing variables marked with RTC_DATA_ATTR is important for the compiler. For example, ...

Dear colleagues, I will appreciate you help in solving the following problem I encounter when programming my ESP32 Lolin32 board. I have defined a structure in RTC memory for keeping calculated up to six time offsets between SNTP and RTC time: typedef struct { struct timeval offset_t[ESP_MAX_TIMESYN...