How to configure Android 4.4.2 to work with two RTCs in the system

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How to configure Android 4.4.2 to work with two RTCs in the system

Contributor I

I am using iMX6 to build a system based on Android Kit-Kat. On the system I have an external RTC chip which is powered by a separate battery. The external RTC chip does not have an interrupt line connected iMX. The external RTC chip is registered under /sys/class/rtc/rtc0.

I have also enabled the internal SRTC on iMX by enabling CONFIG_RTC_DRV_MXC_V2 to build the rtc-mxc_v2.o. The internal SRTC is under /proc/driver/rtc.

Two questions:

  1. When I have both an external RTC and SRTC on iMX enabled on the system, how do I synchronize the SRTC with the external RTC? The time will be kept on external RTC because it is powered by a separate battery so SRTC has to be synchronized with the external RTC.
  2. How do I configure Android so that when it needs to get time, it gets time from the external RTC; and when it needs to set an alarm to wake up the system in suspend, it sets the alarm using the SRTC on iMX not the external RTC?
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NXP Employee
NXP Employee


Unfortunately, what you are willing to do is out of our scope. For that, I highly recommend you to go to professional service support, they can help you.

NXP Professional Services|NXP 

Best Regards,


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