Martin Vychodil 60386410ae System: fix RTCFAST section alignment
This bugfix contains 3 fixes:
1. .rtc_dummy section is removed (not needed for C3)
2. .rtc_text section is padded with 16B for possible CPU prefetch
3. .rtc_text section is aligned to 4B boundary to comply with PMS Memprot requirements
2021-12-22 21:58:20 +01:00
..
2021-12-22 21:58:20 +01:00
2021-03-31 19:17:33 +08:00
2021-08-20 15:00:55 +08:00
2021-02-24 12:16:37 +08:00
2021-03-25 16:09:33 +08:00

System Notes

Timekeeping

The following are the timekeeping mechanisms available and their differences:

  1. System time (esp_system_get_time)

Time with the origin at g_startup_time. The implementation is not handled by esp_system, but it does provide a default implementation using RTC timer. Currently, esp_timer provides system time, since the hardware timers are under the control of that component. However, no matter the underlying timer, the system time provider should maintain the definition of having the origin point at g_startup_time.

  1. esp_timer time (esp_timer_get_time)

This is the time read from an underlying hardware timer, controlled through config. Origin is at the point where the underlying timer starts counting.

  1. newlib time (gettimeofday)

Timekeeping function in standard library. Can be set (settimeofday) or moved forward/backward (adjtime); with the possibility of the changes being made persistent through config. Currently implemented in terms of system time, as the point of origin is fixed. If persistence is enabled, RTC time is also used in conjuction with system time.

  1. RTC time (esp_rtc_get_time_us)

Time read from RTC timer.