esp-idf/components/esp_system
Michael (XIAO Xufeng) b920676e59 pm: add test for RTC using 8MD256 as clock source 2022-05-14 22:35:41 +08:00
..
include
ld
port C2 rtc code 2022-05-09 17:50:54 +08:00
test uart: add default source clock for all targets 2022-05-09 11:26:30 +08:00
test_apps/rtc_8md256 pm: add test for RTC using 8MD256 as clock source 2022-05-14 22:35:41 +08:00
test_eh_frame_parser
CMakeLists.txt Merge branch 'refactor/move_rtc_ctrl_to_esp_hw_support' into 'master' 2022-05-05 11:57:31 +08:00
Kconfig hal: use ROM implementation for systimer and wdt on esp32c2 2022-05-12 05:18:57 +00:00
README.md
app.lf
crosscore_int.c
debug_stubs.c
eh_frame_parser.c
esp_err.c
esp_ipc.c
esp_system.c
fpga_overrides.c
freertos_hooks.c
int_wdt.c hal: use ROM implementation for systimer and wdt on esp32c2 2022-05-12 05:18:57 +00:00
linker.lf
panic.c
sdkconfig.rename
sdkconfig.rename.esp32
sdkconfig.rename.esp32c3
sdkconfig.rename.esp32h2
sdkconfig.rename.esp32s2
sdkconfig.rename.esp32s3
stack_check.c
startup.c esp_system: make dependencies on vfs and esp_wifi optional 2022-05-02 20:47:17 +02:00
system_time.c
task_wdt.c
ubsan.c
xt_wdt.c hw_support: move rtc_ctrl from driver to hw_support 2022-04-29 14:28:09 +08:00

README.md

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.