Anti-mouse overflow multi-screen extended display method based on HPD detection

Abstract

The invention provides an anti-mouse overflow multi-screen extended display method based on HPD (Hot Plug Detection) detection, which comprises the following steps of: manually pulling down an HPD pin by utilizing a Hot Plug Detection (HPD) function in a DVI (Digital Video Interface) transmission protocol, so that a seat computer cannot detect an external display, and actively closing a DVI channel; when the display is switched to the channel, the HPD pin is released, the seat computer detects that the display is mounted again, and extended display is automatically completed; according to the method and the device, mouse overflow in a complex display scene can be prevented.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of multi-screen display of unmanned aerial vehicle ground control station, and particularly relates to a mouse overflow prevention multi-screen extended display method based on HPD detection. BACKGROUND

[0002] The unmanned aerial vehicle ground control station needs to provide functions such as unmanned aerial vehicle flight monitoring, task monitoring, command planning, link monitoring, and health state monitoring, and various functional information needs to be displayed on a seat display in real time. Generally, 2-3 displays are designed for a single control seat of the ground station for information display. However, with the increasing complexity of the unmanned aerial vehicle system, the content required to be displayed by the control seat also increases synchronously, and considering the redundancy design, several seat computers are often cross-connected to 2-3 displays. During the task execution process, the display content is switched as needed.

[0003] However, the display and the seat computer are cross-connected, and if a conventional method is used for switching, the mouse cursor will overflow the screen, causing a false appearance that the mouse is not recognized. SUMMARY

[0004] The purpose of the application is to provide an extended display method for the complex display scenario of multi-computer and multi-display cross-connection of the unmanned aerial vehicle ground station. Based on the HPD (Hot Plug Detection) function of the DVI interface, the HPD signal is artificially lowered by using a soft logic switch, and the display is shielded and multiplexed to prevent the mouse from overflowing in the complex display scenario. The application provides a mouse overflow prevention multi-screen extended display method based on HPD detection, which comprises the following steps: The HPD (Hot Plug Detection) function in the DVI interface transmission protocol is used to artificially lower the HPD pin, so that the seat computer cannot detect the external display, and the DVI channel is actively closed; When the display is switched to this channel, the HPD pin is released, the seat computer detects the display mounting again, and the extended display is automatically completed.

[0005] Preferably, the display comprises a display 0 and a display 1.

[0006] Preferably, the seat computer comprises a seat computer 1 and a seat computer 2.

[0007] Preferably, two seat computers each output two DVI video signals to two displays, forming a cross-connection form.

[0008] Preferably, two displays display one video picture according to seat instructions.

[0009] Preferably, the method further comprises: The seat computer 1 outputs two-way DVI video, DVI0 connects display 0, DVI1 connects display 1 and the DVI2 output by the seat computer 2 connects display 1; When display 1 receives the instruction to select the output picture of seat computer 2, the logical control selection switch is selected to connect the hot plug signal HPD2 connected to seat computer 2, at this time, seat computer 1 detects in real time that when the device is connected, DVI1 is disconnected, only display 0 is detected, the graphic card is in the non-expansion mode, and the mouse moves only in the effective display area of display 0.

[0010] Preferably, the method further comprises: When display 1 receives the instruction of the front panel video switching button or receives the video switching instruction sent by the seat computer through the RS422 serial port, the DVI1 video picture of seat computer 1 is selected, then the logical control selection switch is selected to connect the hot plug signal HPD1 connected to seat computer 1; Seat computer 1 detects in real time that when the device is connected, HPD1 is connected, display 0 and display 1 are detected, the graphic card is set to be in the expansion mode, and the mouse can move in the effective display area of display 0 and display 1.

[0011] Preferably, the implementation principle of the video channel switching / closing of seat computer 2 connected to two displays is the same as that of seat computer 1 connected to two displays.

[0012] The beneficial technical effects of the present application are: The present application provides a mouse overflow prevention multi-screen expansion display method based on HPD detection, which utilizes the hot plug detection function in the DVI interface transmission protocol, uses a logical switch to pull down the HPD pin, so that the seat computer cannot detect the external display, actively closes the DVI channel, and the mouse cannot be dragged to the connected expansion screen when dragging. When the display is switched to this channel, the HPD pin is released, the seat computer detects the display mounting again, and the expansion display is automatically completed. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 A multi-screen expansion display schematic diagram is provided for the embodiments of the present application; Figure 2 A DVI interface principle schematic diagram of the mouse overflow prevention multi-screen expansion display method based on HPD detection is provided for the embodiments of the present application; Figure 3 An implementation schematic diagram of the mouse overflow prevention multi-screen expansion display method based on HPD detection is provided for the embodiments of the present application. DETAILED DESCRIPTION

[0014] This invention provides a multi-screen extended display method for preventing mouse overflow based on HPD detection, as designed below: When two workstations and two monitors are cross-connected, each monitor displays one video stream according to the workstation command. For example, monitor 0 displays the DVI0 video stream from workstation 1, and monitor 1 displays the DVI3 video stream from workstation 2. Since workstation 1 is simultaneously outputting two DVI streams and successfully connected to both monitors 0 and 1, it determines that it is in extended mode. Therefore, when the KVM switches the mouse to monitor 0, after dragging the mouse out of the effective display area of ​​monitor 0, the mouse cursor should continue to appear on monitor 1. However, monitor 1 is displaying the screen from workstation 2, causing the mouse cursor to appear lost and creating the illusion that the mouse is not recognized.

[0015] To solve the above problem, the hot-plug detection (HPD) function in the DVI interface transmission protocol is used. The HPD pin is manually pulled low, so that the host computer cannot detect the external monitor and actively closes the DVI channel. When the monitor switches to this channel, the HPD pin is released, and the host computer detects the monitor again and automatically completes the extended display.

[0016] Seat computer 1 and seat computer 2. Seat computer 1 outputs two DVI video signals. DVI0 is connected to monitor 0, and DVI1 is connected to monitor 1. DVI2, output by seat computer 2, is also connected to monitor 1. When monitor 1 receives an instruction to select to output the screen of seat computer 2, it selects to connect the hot-plug signal HPD2 (HPD1 is disconnected) of seat computer 2 through a logic control selection switch. At this time, when seat computer 1 is detecting connected devices in real time, DVI1 is disconnected (HPD1 is disconnected), and only monitor 0 is detected. The graphics card is in non-extended mode, and the mouse can only move within the effective display area of ​​monitor 0.

[0017] When monitor 1 receives a video switching command from the front panel button or a video switching command sent by the host computer via RS422 serial port, and selects to display the DVI1 video screen of host computer 1, it selects to connect the hot-plug signal HPD1 (HPD2 disconnected) of host computer 1 through the logic control selection switch. At this time, when host computer 1 detects connected devices in real time, HPD1 is connected (HPD2 disconnected), monitor 0 and monitor 1 are detected, the graphics card is set to extended mode, and the mouse can move within the effective display area of ​​monitor 0 and monitor 1.

[0018] The increasingly complex drone systems and on-site display environments urgently require an effective multi-screen extended display method to prevent issues such as mouse overflow.

[0019] This invention provides a method for preventing mouse overflow in multi-screen extended display based on HPD detection. It utilizes the hot-plug detection function in the DVI interface transmission protocol and uses a logic switch to pull the HPD pin low, so that the host computer cannot detect the external monitor and actively closes the DVI channel. When the mouse is dragged, it will not drag onto the connected extended screen. When the monitor switches to this channel, the HPD pin is released, and the host computer detects the monitor again and automatically completes the extended display.

[0020] Therefore, this solution provides a multi-screen extended display method based on HPD detection to prevent mouse overflow. It only requires adding a logic switch to achieve the shielding and mounting of external screens, making it simple and reliable. Therefore, it has significant practical value and widespread applicability.

[0021] To achieve multi-screen extended display with anti-mouse overflow based on HPD detection, the present invention designs the following multi-screen extended display method.

[0022] Specific embodiments are described in conjunction with the accompanying drawings.

[0023] like Figure 1 The image shows a schematic diagram of a multi-screen extended display.

[0024] A multi-screen extended display method for preventing mouse overflow based on HPD detection is analyzed and implemented using two host computers and two monitors. The system includes host computer 1 and host computer 2, and monitors 0 and 1. Each host computer outputs two DVI video signals to both monitors, forming a cross-connection. Each monitor displays one video signal according to the host computer's instructions; for example, monitor 0 displays the DVI0 video signal from host computer 1, and monitor 1 displays the DVI3 video signal from host computer 2. At this time, because host computer 1 is simultaneously outputting two DVI signals and successfully connected to both monitors 0 and 1, host computer 1 determines that it is in extended mode. Therefore, when the KVM switches the mouse to monitor 0, after the mouse is dragged out of the effective display area of ​​monitor 0, the mouse should continue to appear on monitor 1. However, monitor 1 displays the screen of host computer 2, causing the mouse to disappear and creating the illusion that the mouse is not recognized.

[0025] Conversely, the same situation occurs when using KVM to switch the mouse to monitor 1.

[0026] like Figure 2 The diagram shown is a schematic of the DVI interface for a multi-screen extended display method based on HPD detection to prevent mouse overflow.

[0027] To prevent mouse operations from becoming unobservable when the mouse moves to a non-displayed DVI channel while multiple monitors are in extended display mode, a method is proposed to disable non-displayed DVI channels on the monitor, effectively shutting down channels not displayed in extended mode. The main principle is to utilize the Hot Plug Detection (HPD) function in the DVI interface transmission protocol. By artificially lowering the HPD pin, the host computer cannot detect the external monitor, actively disabling the DVI channel. When the monitor switches to this channel, the HPD pin is released, and the host computer detects the monitor again, automatically completing the extended display.

[0028] According to the DVI digital interface specification, the main function of pin 16 of DVI is hot-plug detection (HPD). This signal serves as the basis for whether the host computer sends TMDS (transition minimized differential signaling) to the monitor. The purpose of hot-plugging is that after the monitor is connected to the host computer's DVI interface, the computer can detect whether the monitor is properly connected through the HPD pin. When the HPD is detected to be low (below 0.8V), the host computer generates an event interrupt based on the detection of the HPD pin, requiring the computer to start reading the EDID (Extended Display Identifier Data) information of the external monitor through the DDC channel, and configure data such as resolution and GAMMA value according to the EDID information, and activate TMDS image data transmission. At this time, the monitor starts displaying the image.

[0029] When the monitor is connected to the computer, the +5V power supply generated and output to the monitor by the computer passes through pin 14 of the DVI interface and, through resistor R467, is directly output to pin 16 of the DVI interface. At this time, the voltage on the HPD pin is higher than 2V, the computer recognizes that the external DVI monitor is connected, generates an event interrupt, and reads the data stored in the EPPROM U56 of the monitor through the DDC channel (pins 6 and 7) of the DVI interface. Based on the data, it sends image data to the monitor through the TMDS channel (pins 1, 2, 9, 10, 17, 18, 23, and 24), and the monitor starts displaying normally. When the monitor is disconnected from the DVI interface, the HPD voltage drops below 0.8V, the computer recognizes that the external DVI monitor has been detached, the computer generates an interrupt event, notifies the graphics card to stop sending TMDS signals, and shuts down this DVI channel.

[0030] The principle behind manually disabling the DVI channel is as follows: When the DVI channel is not the currently displayed channel, the monitor's MCU sets HDMI_A_HOT to high, transistor Q4 conducts, HPD is pulled low, the TMDS signal is terminated, and the DVI channel is shut down. When this DVI channel becomes the currently displayed channel, the MCU releases HPD, the computer can detect the monitor, the monitor is connected, and the TMDS image signal is output to the monitor.

[0031] like Figure 3 The diagram illustrates the implementation of a multi-screen extended display method for preventing mouse overflow based on HPD detection. A two-channel input video signal switching / off logic is designed for the monitor. When the monitor displays one DVI signal according to the instruction, the logic controls the shutdown of the other DVI video signal. The two input video signals can be switched via the monitor's video switching button or by receiving instructions from the computer via an RS422 serial port.

[0032] Seat computer 1 and seat computer 2. Seat computer 1 outputs two DVI video signals. DVI0 is connected to monitor 0, and DVI1 is connected to monitor 1. DVI2, output by seat computer 2, is also connected to monitor 1. When monitor 1 receives an instruction to select to output the screen of seat computer 2, it selects to connect the hot-plug signal HPD2 (HPD1 is disconnected) of seat computer 2 through a logic control selection switch. At this time, when seat computer 1 is detecting connected devices in real time, DVI1 is disconnected (HPD1 is disconnected), and only monitor 0 is detected. The graphics card is in non-extended mode, and the mouse can only move within the effective display area of ​​monitor 0.

[0033] When monitor 1 receives a video switching command from the front panel button or a video switching command sent by the host computer via RS422 serial port, and selects to display the DVI1 video screen of host computer 1, it selects to connect the hot-plug signal HPD1 (HPD2 disconnected) of host computer 1 through the logic control selection switch. At this time, when host computer 1 detects connected devices in real time, HPD1 is connected (HPD2 disconnected), monitor 0 and monitor 1 are detected, the graphics card is set to extended mode, and the mouse can move within the effective display area of ​​monitor 0 and monitor 1.

[0034] When the second computer is connected to two monitors, the principle for switching / closing the video channel is the same.

Claims

1. A method for preventing mouse overflow in multi-screen extended display based on HPD detection, characterized in that, The method includes: By using the hot-plug detection (HPD) function in the DVI interface transmission protocol, the HPD pin is manually pulled low, so that the seat computer cannot detect the external monitor and actively closes the DVI channel; When the monitor switches to this channel, the HPD pin is released, and the seat computer detects the monitor being mounted again, automatically completing the extended display.

2. The method according to claim 1, characterized in that, The display includes display 0 and display 1.

3. The method according to claim 2, characterized in that, The seat computer includes seat computer 1 and seat computer 2.

4. The method according to claim 3, characterized in that, Each of the two computer seats outputs two DVI video signals to two monitors, forming a cross-connection.

5. The method according to claim 4, characterized in that, Each of the two monitors displays one video feed according to the seat command.

6. The method according to claim 5, characterized in that, The method further includes: Seat computer 1 outputs two DVI video signals: DVI0 is connected to monitor 0, and DVI1 is connected to monitor 1. Seat computer 2 outputs DVI2, which is also connected to monitor 1. When monitor 1 receives an instruction to select the output screen of host computer 2, it selects to connect the hot-plug signal HPD2 of host computer 2 through the logic control selection switch. At this time, when host computer 1 detects connected devices in real time, DVI1 is disconnected, only monitor 0 is detected, the graphics card is in non-extended mode, and the mouse can only move within the effective display area of ​​monitor 0.

7. The method according to claim 6, characterized in that, The method further includes: When display 1 receives a video switching button command from the front panel, or receives a video switching command sent by the host computer via RS422 serial port, and selects to display the DVI1 video screen of host computer 1, it selects to connect the hot-plug signal HPD1 of host computer 1 through the logic control selection switch. When computer 1 detects connected devices in real time, HPD1 is activated, monitor 0 and monitor 1 are detected, the graphics card is set to extended mode, and the mouse can move within the effective display area of ​​monitor 0 and monitor 1.

8. The method according to claim 7, characterized in that, The principle behind switching / disabling the video channel when two monitors are connected to seat computer 2 is the same as that when two monitors are connected to seat computer 1.

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