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===Axel Lite===
A spreadsheet is available for download at [[media:AxelLite-routing.zip|this link]] containing detailed information about Axel Lite routing. These information should be used to check nets matching of the overall system (carrier board + SOM).
==Real-time clock (RTC)==
===Axel Lite===
To understand how Axel Lite's real-time clock works, first it is necessary to describe how it is powered.
Real-time clock is integrated in iMX6 processor. As such, it belongs to SNVS power domain. This domain, in turn, is powered by PMIC, via PMIC_VSNSV rail (see also [[Power_(AxelLite)|this page]]). PMIC integrates a sort of switch. When 3V3VIN voltage is applied, this is used to power SNVS domain. Otherwise energy is drawn from PMIC_LICELL, if a coin cell battery is connected (for more details please refer to <ref name="MMPF0100">NXP, ''MMPF0100 - PF0100 Data sheet: Advance Information''</ref>).
It is worth remembering that 3.0V lithium batteries are supported. When Axel Lite enters RTC mode and 3V3VIN voltage is removed, current absorption from PMIC_LICELL pin is about 135uA. This value is relatively high with respect to the typical lithium coin cell battery capacity (10 - 50mAh) that may not satisfy RTC keep alive time requirement. In this case, please consider the use of an external low-power RTC device.
