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iPhone mobile phone commonly used bus

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In this video, we mainly explain the PEIe bus

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PCIe bus is a high-speed serial computer expansion bus

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It was proposed by Intel in 2001 to replace the old PCI, PCI-X and AGP bus standards

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The PCIe bus is also used in our mobile phones

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There are many versions of the PCIe bus

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Different versions transfer at different speeds

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The lines used in different versions are also different

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The less lines that are used, the slower the transmission speed

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The more wires used, the faster he transfers

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Generally we call it throughput

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There are X1, X4, X8, X16 in this version

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X16 represents lines with 16 groups and 32 lines

twenty four

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The more lines and the higher the version, the more data he sends out every second

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The PCIe management module contains reset, clock and data

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In the Apple mobile phone, the CPIe bus is mainly used in the circuit from the CPU to the wifi

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CPU to hard disk, CPU to baseband circuit

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The amount of data required by these circuits is very large, so they use the PCIe bus

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Next, we will take the Qualcomm model of iPhone x as an example to find the PCIe bus between the CPU and the hard disk.

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We first find the hard disk in the annotation diagram

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Go to the drawing to search for the hard disk location number

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After finding the hard disk, we can look at the lines around the hard disk

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The one that identifies PCIe is the PCIe bus from the hard disk to the CPU

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In this line we can see that the PCIe bus has a set of clocks

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The clock is directly connected to the CPU

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There are two other groups of data RX reception and TX transmission of the PCIe bus

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The data line has a characteristic

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They all pass through the coupling capacitor first, and then connect to the cpu

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This bus is similar to the LPDP bus of the camera, and a coupling capacitor is connected in the middle

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If the coupling capacitor is connected to the line, it generally means that the data volume of this line is very large.

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It will transmit the signal through the coupling capacitor

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If there is a problem with the PCIe bus, it will cause the corresponding function to be unavailable

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For example, if the PCIe bus from the hard disk to the CPU is disconnected, the CPU cannot read the hard disk.

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resulting in no boot

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That's all for this video