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Hello, everyone, today we are going to learn the four major working conditions of RTC circuit

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This course consists of two parts,

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RTC circuit introduction, RTC circuit four major working conditions

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First, let's look at a brief introduction to the RTC circuit

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RTC is also called real time clock circuit, also can be called CMOS circuit

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RTC circuit includes RTC module inside PCH and 32.768KHz clock crystal outside the PCH,

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RTC reset circuit and CMOS battery

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It is mainly used to store time, date, and ESCD files

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The RTC module in PCH mainly includes a real-time clock module and a register,

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which is mainly used to ensure the normal operation of time and store CMOS information

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Common faults: After the button battery is removed,

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information such as the time and date is lost, and BIOS Settings are lost

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Because without an adapter and without a large battery,

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the only source of power for the RTC circuit is the button battery

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If the button battery is removed,

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the information stored in it is lost

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Next let's look at the RTC circuit four working conditions

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In this 100 series chipset standard timing diagram,

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the first requirement is to meet the RTC circuit conditions

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These several conditions include the RTC circuit of the power supply, VCCRTC

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This power supply is provided by the button battery,

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or the built-in main battery, and it is a 3.3V high level

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RTCR#, SRTCR#, these two are reset signals of RTC circuit, active low level

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Strictly speaking, the first is the reset signal of the RTC circuit

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and the second is the reset signal of the ME module inside the PCH

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The two reset signals in the circuit are supplied by RTC through resistor and capacitor delay

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The resistor is usually 20K, the capacitor is 1uF,

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and the delay time is usually more than 20 milliseconds

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When the chipset is powered, the PCH will power the crystal

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The 32.768KHz crystal starts to vibrate, providing the RTC circuit with the reference clock frequency

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One power supply, two reset, a clock,

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these are the RTC circuit four major working conditions

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If any of the conditions is not normal, it will not be able to start up normally