Ivan Grokhotkov 708e99497b
global: add dependency on esp_timer component and include esp_timer.h
Some components were including esp_timer.h without declaring a
dependency on esp_timer component. This used to work due to a
transitive public dependency on esp_timer from freertos component.
Add explicit dependencies where needed.
Also some source files were using esp_timer functions without
including the header file. This used to work because esp_timer.h was
included from freertos port header file. This commit adds esp_timer.h
includes where needed.
2022-04-25 18:39:23 +02:00
..
2021-03-31 19:17:33 +08:00
2022-03-01 19:49:24 +03:00
2021-02-24 12:16:37 +08:00
2021-03-25 16:09:33 +08:00
2022-02-09 23:05:45 +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.