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iphone mobile phone commonly used bus

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In this video we mainly explain the UART bus

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The UART bus is a universal asynchronous transceiver bus

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Asynchronous means that data can be transmitted synchronously without additional clock lines

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The main function of the UART bus is to convert the signal to be transmitted between serial communication and parallel communication

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The serial bus means that when a chip sends data to another chip, it sends it serially in time.

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Then this is serial data

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Parallel data means that a lot of data can be transmitted simultaneously from chip to chip

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Simultaneous transmission is called parallel data

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UART bus converts parallel data into serial data

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Or convert serial data to parallel data

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The UART bus consists of two wires

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One is to receive RX and the other is to transmit TX

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We can see according to the iPhone mobile phone bus architecture

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The UART bus is used between the CPU and the Bluetooth WIFI

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The UART bus is used between the CPU and the baseband

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Next, let's find out the UART bus between the CPU and WIFI

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Let's take the iPhone X as an example, the search method for other models is the same

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Because WIFI has few pins, we start to search from WIFI

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Find the WIFI location number in the marked map

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Then go to the drawing to search for the location number of WIFI

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After searching for the WIFI location number, we can look at the line

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The English logo UART represents the UART bus from WIFI to CPU

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The English logo UART_WLAN_TO_AP indicates that the line is the UART bus from WIFI to CPU

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By looking at the bitmap, we can find that

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The signal is directly connected to the CPU by WIFI, and there is no fuse resistor in the middle

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If there is a problem with this UART bus, it will prompt that the WIFI password is wrong

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Even if the password entered is correct, he will prompt an error

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In this case, the UART bus from WIFI to CPU is disconnected.

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Next, let's look for the UART bus between the CPU and the baseband

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We first find the baseband position number in the annotation diagram

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Go to the drawing to search for the baseband position number

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According to the English outside the frame diagram

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The one that identifies UART represents the UART bus of the baseband to the CPU

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In the current page, the identification UART_BB_TO_AOP_RXD is the reception of the UART bus of the baseband to the CPU

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He is the baseband directly connected to the CPU

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The signal below is UART_AOP_TO_BB_TXD, indicating that it is the transmit signal from the CPU to the baseband

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It is also directly connected to the baseband by the CPU

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That's all for this video