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Hello everyone, today we are going to learn about the reset signals

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The reset signal is called reset, abbreviated as RST, which means to start over,

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that is, to initialize or reset

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This reset signal at the beginning of the boot,

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it will automatically complete the reset, from low level to high level

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During startup, when the CPU receives the switch signal,

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the CPU will emit SLP_S3# and SLP_S4# to turn on all power supplies

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SLP_S4# is usually used to enable the power supply of S4 state,

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such as the main power supply of memory and VPP power supply of memory

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SLP_S3# is usually used to enable the power supply of S0 state, VCCST, VCCSTG, etc

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After all the power supplies are normal,

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these PG signals are finally sent to the CPU

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For example, PCH_PWROK, SYS_PWROK, VCCST_PWRGD, CPUPWRGD

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They pass through the internal AND gate and delay to produce a platform reset signal,

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which will change from low to high

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If any power supply is abnormal, such as CPU power supply is abnormal,

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the PG signal will not enter the AND gate, and there will be no PCH_PWROK

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In the absence of a PG signal, there will be no platform reset signal

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If any power supply is abnormal,

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this AND gate will not output ALL_SYS_PWRGD,

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and there will be no subsequent CPU power, PCH_PWROK, and SYS_PWROK

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This is the platform reset signal

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When we say no reset in maintenance, we mean that no voltage is measured at the reset test point

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The reset test point is usually pin 52 of interface M.2

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M.2 Port has two kinds: one is to plug the solid-state disk,

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and the other one is to plug the wireless network card

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We usually refer to this M.2 interface for wireless card insertion,

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whose pin 52 is the platform reset test point

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Pin 22 of the Mini PCIe slot is also the platform reset test point

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The voltage of platform reset signal is 3.3V

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The platform reset is low before the power supply is normal

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After the power supply is normal, it will change from low level to high level

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This "#" indicates that the low level is valid

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After the power supply is normal,

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it remains low for a period of time, which is called reseting

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When the reset signal changes from a low level to a high level,

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it is called a complete reset, or the reset is end

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Okay, that's the reset signal