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Hello everyone, in this lesson we will briefly introduce the digital display interface

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The digital display interface is an interface that uses digital signals to transmit display screens

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In daily life, the most common digital interfaces are HDMI, DP and DVI_D

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Since the DVI interface is a transitional interface, it is not used much,

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so we will not talk about it here

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We focus on the HDMI interface and DP interface

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Although the HDMI interface and the DP interface are two completely different interfaces,

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their workflow and pins are similar

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First, let's look at the pins of the HDMI interface

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The HDMI interface has a total of 19 pins, including 3 sets of data lines and a set of clock lines

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They are all used to transmit the display screen

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In addition to these 3 sets of data lines and a set of clock lines, there is also a pair of serial buses

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This pair of serial buses is used to read screen information

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Read screen manufacturer, resolution size and other information

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The HDMI interface also has power supply and hot plug detection pins

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The power supply of the HDMI interface is 5V

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The hot plug detection pin is used to detect whether there is an HDMI device plugged in.

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When the HDMI display is inserted, the hot plug detection pin will become high

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After unplugging the device, it goes low

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Although the HDMI interface has 19 pins, we don't need to take care of these shielding pins,

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reserved pins, and CEC pins.

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Then we look at the DP interface

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The DP interface has a total of 4 sets of data lines, one more set than the HDMI interface

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In addition to these 4 sets of data lines, there is also a set of AUX buses

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At the same time, the DP interface also has interface power supply and HPD

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This HPD is hot plug detection

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The power supply of the DP interface is 3.3V, and the power supply of the HDMI interface is 5V

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The four sets of data lines of the DP interface are also used to transmit the display screen

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The AUX bus is not the same

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At the beginning, the AUX bus was equivalent to the serial bus of the HDMI interface,

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used to read the information of the screen

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And when the DP interface works normally, the AUX bus can also be used as a clock line

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It can be seen that the data line of the DP interface is basically the same as that of the HDMI interface,

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except that the serial bus and the clock line are replaced by the AUX bus.

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Well, the above is a brief introduction of the digital display interface