Difference between revisions of "How to adjust Hardware RTC clock"

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In IGEP Boards, MPU and PMIC contains each one a RTC clock:
 
In IGEP Boards, MPU and PMIC contains each one a RTC clock:
  
* '''RTC System clock''': system clock is controlled by OMAP processors using its internal RTC peripheral. Every bootup, the default firmware copies the hardware clock data from /dev/rtc to system clock data to preserve the clock.
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* '''RTC System clock''': system clock is controlled by OMAP processors using its internal RTC peripheral. Every bootup, the default firmware copies the hardware clock data from /dev/rtc to system clock data to keep clock up to date.
  
 
* '''RTC Hardware clock''': hardware clock is controlled by PMIC IC using its internal RTC peripheral. RTC PMIC can afford two behaviours:
 
* '''RTC Hardware clock''': hardware clock is controlled by PMIC IC using its internal RTC peripheral. RTC PMIC can afford two behaviours:

Revision as of 12:48, 11 November 2013

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Overview

Real time clock (RTC) is a computer clock (most often in the form of an integrated circuit) that keeps track of the current time. RTCs are present in almost any electronic device which needs to keep accurate time. More general information here.

In IGEP Boards, MPU and PMIC contains each one a RTC clock:

  • RTC System clock: system clock is controlled by OMAP processors using its internal RTC peripheral. Every bootup, the default firmware copies the hardware clock data from /dev/rtc to system clock data to keep clock up to date.
  • RTC Hardware clock: hardware clock is controlled by PMIC IC using its internal RTC peripheral. RTC PMIC can afford two behaviours:
    • RTC battery is not used: PMIC RTC peripheral keeps hardware clock alive when OS isn't running and power source is active.
    • RTC battery is used: PMIC RTC peripheral keeps hardware clock alive when OS isn't running and backup battery powers the backup state as far as the input voltage is high enough.

Requirements