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Hello everyone锛宼oday we will learn about the generation process of each power supply in the Apple A2337 circuit

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We have introduced the generation of 3.8V main standby power supply in the previous course

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The main standby power supply directly supplies power to the two power chips of U8100 and U7700

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Among them, U7700 is the auxiliary power chip, and U8100 is the main power chip

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Because after this machine is plugged in, it will turn on and power on automatically

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Therefore, we will not introduce the steps of pressing the switch

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When the main chip gets the main power supply, its crystal oscillator will start to work

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The position number of the crystal oscillator is Y8301,

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and the frequency is 32.768KHz, which is in this position in the real product

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The big one is the main power chip, and the small one is the secondary power chip

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There is a crystal oscillator next to the main power supply, which is a 32.768KHz crystal oscillator

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After the crystal oscillator starts to oscillate,

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the main power chip and the secondary power chip will communicate through the I2C bus

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The auxiliary power chip is managed by the main power chip

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The main power supply chip will control and generate various power supplies,

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including: hard disk power supply, various power supplies required by the M1 processor,

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such as 1.06V, 0.6V, 1.25V, 0.72V, PPVDD_GPU_AWAKE, etc.

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After each power supply is sent to the M1 processor,

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the 24MHz crystal oscillator of the M1 processor starts to vibrate

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At the same time, the M1 processor will also get the clock provided by the power chip

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This is the 32.768KHz clock sent by the power chip

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Then the power chip will continue to provide clock and reset signals to the M1 processor

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One is PMU_RESET_L, one is TPT_TST_CLKOUT

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After the M1 processor gets power supply, clock and reset signal,

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it starts to read the information in SOCROM

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If there is a problem with the information in the SOCROM, or M1 cannot read this program,

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it will cause the adapter not to boost the voltage

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After the M1 processor reads the program,

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it will communicate with the CD3217 through the I2C0 bus

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Before this, the Thunderbolt chip must first read the program information,

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and complete the communication with CD3217

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After receiving the information sent by the M1 processor,

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the CD3217 communicates with the adapter through the CC bus,

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requesting the adapter to provide a voltage and current that can satisfy the machine's work

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Then the adapter will output a boosted 20V according to the requirements of CD3217

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In this boost process, many chips are involved,

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such as Thunderbolt chips, logic chips, chip CD3217, charging chips, and various power chips

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While the M1 processor is communicating with the CD3217,

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it is also reading the information of its own logic chip

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There is a program in this logic chip,

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the program is bound to the Apple system,

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and this chip is bound to the M1 processor

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Therefore, when replacing the M1 processor, it must be replaced together with the chip

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Next, the M1 processor reads the system information in the hard disk through the PCIE bus,

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and reads some underlying data of the hard disk through the I2C bus

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But after our test, it does not need to read hard disk data before the adapter boosts the voltage

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It will be read after the adapter boosts and starts to enter the system

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The read system information needs to be compared with the information in the logic chip

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to verify the integrity of the system

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Ok, this is the generation process of each power supply