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iPhone Wi-Fi circuit repairing

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This video mainly explains the working principle of the Wi-Fi circuit of iPhone 6 to iPhone X, and iPhone XR models

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The working principle of the Wi-Fi circuit of these models is the same,

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the signal connection method is basically the same,

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and the steps of repairing are basically the same

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Wi-Fi working principle step 1

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When the battery is buckled or the adjustable power supply is connected,

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the PP_VDD_MAIN main power supply will be generated

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The main power supply will first provide the working voltage for the Wi-Fi chip

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Step 2, after triggering the boot,

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the main power supply will output 1.8V power supply to provide working voltage for Wi-Fi

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Step 3, the main power supply outputs a 32KHz clock signal for the Wi-Fi chip

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Step 4, after the Wi-Fi chip has power supply and the clock signal,

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it will convert VIN_LDO power supply for itself,

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and then returns to the inside of the chip to provide itself with working voltage

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Step 5, when booting to the Wi-Fi circuit,

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the CPU first sends a wake-up signal to wake up the Wi-Fi chip,

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so that the chip is ready to start working

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Step 6, when starting to the Wi-Fi circuit,

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the main power supply sends a restart signal to the Wi-Fi chip

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Step 7, when the Wi-Fi chip has three-way power supplies, clock signal, wake-up signal and open signal,

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Wi-Fi can work normally

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The CPU will detect the Wifi chip through the PCIE bus

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After the CPU detects the Wi-Fi chip, we can see the Wi-Fi address on the About This iPhone interface

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If there is no Wi-Fi address, it means that the CPU has not detected the Wi-Fi chip

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Step 8, after the Wi-Fi chip communicates with the CPU,

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the Wi-Fi chip can work normally, and the signal transceiver circuit is turned on

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In the transceiver circuit, 2.4G and 5G signals will all start working, search for router signals

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Step 9, the Wi-Fi chip sends the searched router signal to the CPU through the UART bus,

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and the router name will be displayed on the screen

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Step 10, when we select the router signal and enter the password,

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the CPU will send the password data to the Wi-Fi chip through the UART bus

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Step 11, the Wi-Fi chip sends the received password information to the router

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through the antenna signal for verification

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If the verification is successful, it will establish a connection with the mobile phone

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Step 12, the Wi-Fi chip sends the received data to the CPU through the PCIE bus

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At this time, the mobile phone realizes the Internet function

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In the iPhones, as long as it uses large-flow data transmission, it will use the PCIE bus

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For example, baseband to CPU, hard disk to CPU, Wi-Fi to CPU,

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high-speed data transmission will take the PCIE bus

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If the signal on the left side of the Wi-Fi chip is abnormal, the Wi-Fi cannot be turned on

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If the signal on the right side is abnormal,

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the Wi-Fi signal cannot be searched, or the Wi-Fi signal is weak

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When troubleshooting Wi-Fi cannot be turned on,

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we focus on the working conditions on the left side of Wi-Fi

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When troubleshooting the weak Wi-Fi signal,

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we need to check the signal sending and receiving lines on the right side of Wi-Fi

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The UART bus is the bus used by the baseband to transmit data

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For example, if the mobile phone turns on the hotspot function,

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it will use the signal of the baseband to Wi-Fi to transmit

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Ok, that's all for this video