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==IntroductionReal-time clock options==
This article describes the options available for the real-time clock (RTC) implementation on SBC Lynx.
===i.MX6UL's native RTC (default option)===
The default option is based on i.MX6UL's native RTC. The simplified block diagram of this solution is depicted in the following image.
When the system is powered off, on-board battery powers SNVS domain of i.MX6UL processor that includes native RTC. Under these conditions, the typical current drawn from the battery is 100 uA. In case a 17 mAh battery is used (i.e. Panasonic ML-1220/V1AN), battery life is about 170hours.
This solution is quite simple and cheap. However, the timekeeping operation time is relatively short. In case a longer timekeeping operation time is required, it is possible to not populate the on-board battery and to connect a bigger one to the connector J56. For more information, please contact [mailto:sales@dave.eu Sales department]. ===ST M41T83 (alternative option)===This option is based on [http://www.st.com/en/clocks-and-timers/m41t83.html ST M41T83] RTC. The simplified block diagram of this solution is shown by the following image. [[File:SBCLynx-RTC-alternative.png|thumb|center|400px|Alternative RTC implementation]] Typical current drawn from the battery is 370 nA, when the system is powered off [1]. Thus expected battery life is about 5 years, in case a battery with nominal capacity of 17 mAh is used. This solution is more expensive but guarantees a longer timekeeping operation time, because M41T83 power consumption is very low. In any case, it is possible to not populate the on-board battery and to connect a bigger larger one to the connector J56 to achieve an even longer operation time. For more information, please contact [mailto:sales@dave.eu Sales department]. [1] This consumption largely varies depending of RTC configuration. This figure refers to the configuration detailed in the following registers dump:<pre>tenths: 0x47seconds: 0x22minutes: 0x45hours: 0x11day: 0x02date: 0x17month: 0x01year: 0x17calib: 0x80WD: 0x00alm1: 0x40alm1: 0x00alm1: 0x00alm1: 0x00alm1: 0x00flags: 0x04timer: 0x00timerctl: 0x03ancal: 0x00square: 0x10alm2: 0x00alm2: 0x00alm2: 0x00alm2: 0x00alm2: 0x00RAM: 0x00RAM: 0x00RAM: 0x00RAM: 0x00RAM: 0x08RAM: 0x00RAM: 0x00RAM: 0x89</pre>