Nexcom EBC-3A1 Series, User Manual

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3.3.5. RTC & Watchdog
RTC & Watchdog Information
A real-time clock (RTC) keeps track of the current time, and ICM-3011 will synchronize
hardware clock to system clock when boot.
Watchdog timer, during normal operation, the computer regularly resets the watchdog
timer to prevent it from elapsing, or "timing out". If, due to a hardware fault or program
error, the computer fails to reset the watchdog, the timer will elapse and generate a
timeout signal.
RTC & Watchdog Specification
Name Value
RTC Frequency Tolerance
5
±
23 ppm
Watchdog 0.5 ~ 128 seconds (unit: 0.5s)
* Equivalent to 1 minute of monthly deviation.
RTC & Watchdog Device Node
Device Device node
RTC /dev/rtc0
Watchdog /dev/watchdog
RTC & Watchdog Example
Example Code:
https://github.com/embux/Example/tree/master/watchdog
Example Commands:
#1: show RTC time.
root@ICM-3011:~# hwclock
Tue Aug 7 03:47:34 2018 0.000000 seconds
#2: Set the System Time from the Hardware Clock.
root@ICM-3011:~# hwclock -s
#3: Set the Hardware Clock to the current System Time.
root@ICM-3011:~# hwclock -w