A method for transmitting an external interrupt of a vehicle display screen end using a DP extension protocol

Abstract

The application discloses a method for transmitting external interruption of a vehicle display screen end by using a DP extension protocol, and comprises the following steps: an Aux GPIO suspension identifier is predefined as a special identifier bit in an AUX register for judging external GPIO interruption, and a receiving end feeds back external interruption to a source end; when the remote device gives an interruption, the receiving end identifies the interruption request through a local GPIO, writes an interruption effective identifier into a DPCD SINK SPECIFIC IRQ address through a DP module, sets the Aux GPIO suspension identifier to 1, pulls down an HPD pin, and notifies the source end; the source end reads corresponding and judges whether there is additional interruption after detecting the pull-down; if yes, the source end reads an interruption judgment identifier bit to judge whether it is external GPIO interruption; and the source end calls an external GPIO interruption processing function after clearing the identifier. The application can complete interruption notification and data interaction without a serializer, a deserializer, and without relying on an external interruption signal.

Description

Technical Field

[0001] This invention relates to the field of data transmission technology for vehicle display systems, and specifically to a method, device, and storage medium for transmitting external interrupts at a vehicle display screen using the DP extended protocol. Background Technology

[0002] Currently, in-vehicle display systems use in-vehicle serial deserializers to solve the problem of cross-board transmission of video and touch information. Some other solutions, such as using DP direct transmission to transmit display information, rely on an additional USB controller to transmit touch information.

[0003] The two solutions described above each have two shortcomings in their implementation: The drawback of the first conventional approach is that the serializer and deserializer chips are expensive, and the serial deserialization scheme increases hardware complexity and power consumption. The drawback of the second alternative solution is that it introduces an additional USB controller, which limits the selection range of the main control MCU, increases costs, and occupies USB ports.

[0004] Therefore, this application proposes a method for transmitting external interrupts at the vehicle display screen using the DP extended protocol to solve the above-mentioned technical problems. Summary of the Invention

[0005] The main objective of this invention is to provide a method for transmitting external interrupts on an in-vehicle display using the DP extended protocol, bypassing serializers and deserializers or a DP mode video transmission + USB touch transmission scheme. It uses the I2C over AUX function of the AUX interface within the DP protocol to transmit touch data and uses HPD to transmit interrupt signals. From the perspective of physical interface, it fully complies with the DisplayPort standard definition and completes the transmission of touch data without adding an additional physical interface, thereby solving the technical problems mentioned in the background art.

[0006] The present invention solves the above-mentioned technical problems by adopting the following technical solutions: A method for transmitting external interrupts at an in-vehicle display using the DP extended protocol includes the following steps: S1. The Aux GPIO pending flag is predefined in the reserved register of the DP AUX channel, usually bit 0 of AUX register 40Ch, as a dedicated flag bit in the AUX register for judging external GPIO interrupts, and is used by the DP receiver IC to feed back external interrupts to the DP source IC; S2. When a remote device issues an interrupt based on a specified method, the specific interrupt method is not limited (high level, low level, high pulse, low pulse are all acceptable). It is only necessary for the remote device and the DP receiver to reach an agreement on the triggering method. Then the DP receiver IC will trigger through local GPIO interrupt to identify the interrupt request issued by the remote device. S3. After recognizing the interrupt request, the DP receiver IC writes the interrupt valid flag to the DPCD SINK_SPECIFIC_IRQ address in the DPCD register through the self-device DP module, and then sets the Aux GPIO pending flag (the dedicated flag bit in the AUX register used to determine external GPIO interrupts / bit 0 of AUX register 40Ch) to 1; S4. The DP receiver IC pulls the HPD pin low and holds it for 0.5 to 1 ms before restoring it to a high level and notifying the DP source IC. After the S5.DP source IC detects the HPD low signal, it reads the DPCD SINK_SPECIFIC_IRQ address and determines whether there is an additional interrupt. If so, it reads the interrupt judgment flag bit (Aux GPIO pending flag) in the AUX register to determine whether it is an external GPIO interrupt. S6.DP source IC clears the flag from the above steps, and then calls the pre-registered external GPIO interrupt handling function to handle the business logic corresponding to the external GPIO interrupt.

[0007] Preferably, if an external interrupt is still triggered after the DP source IC clears the flag in step S6, the DP receiver IC will detect the GPIO interrupt again and repeat steps S2 to S6 until the interrupt signal of the remote device is released.

[0008] Preferably, the DP source IC reads the Aux GPIO pending flag after reading DPCD_SINK_SPECIFIC_IRQ according to custom requirements to determine whether there is an external GPIO interrupt. If there is an interrupt, the corresponding interrupt handling function (e.g., touch interrupt handling function) on the host side is executed.

[0009] Preferably, the DP receiver IC is used to identify the interrupt signal initiated by the remote end through the local GPIO according to the specified configuration method, and set the DPCD_SINK_SPECIFIC_IRQ flag and the Aux GPIO pending flag in the internal DPCD register, and then trigger the HPD interrupt according to the DP protocol standard.

[0010] Preferably, the configuration method specified by the DP receiver IC during the interrupt signal identification process is set to level / edge trigger, high / low level active.

[0011] As can be seen from the above technical solution, the present invention provides a method for transmitting external interrupts at the vehicle-mounted display screen using the DP extended protocol. Compared with the prior art, the present invention has the following advantages: 1. This invention enables the transmission of external interrupts from the vehicle display screen to the host by extending the DP AUX communication protocol. It eliminates the need for serializers, deserializers, and USB channels to transmit external interrupt signals such as touch signals. Interruption notification and data interaction can be completed solely through the standard DisplayPort interface and wiring harness. This eliminates the need for additional non-standard connectors and dedicated communication wiring harnesses. By simplifying the hardware architecture and wiring design of the vehicle display system, it further reduces the connection complexity and hardware cost between the vehicle host and the display screen.

[0012] 2. This invention does not require the use of MCUs or bridge chips that support USB functionality, thus avoiding hardware overhead, driver development, and compatibility issues caused by additional chips. Reliable reporting and processing of screen interrupts can be achieved simply by extending the protocol layer on the existing DP protocol, which can improve system integration and stability, while also shortening the development cycle. It is more suitable for automotive display scenarios with high requirements for cost, reliability, and simple architecture.

[0013] It should be understood that the descriptions in this section are not intended to identify key or essential features of embodiments of the invention, nor are they intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Of course, implementing any product of the invention does not necessarily require achieving all of the advantages described above simultaneously. Attached Figure Description

[0014] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic diagram of system data transmission interrupted by the HPD+ extended protocol according to the present invention; Figure 2 This is a schematic diagram of the data transmission process interrupted by the HPD+ extended protocol in this invention. Figure 3 This is a schematic diagram of the data processing for transmission interruption according to the present invention; Figure 4 This is a schematic diagram illustrating the data processing during transmission interruption in an existing serial deserialization scheme. Figure 5 This diagram illustrates the data processing during transmission interruptions in the existing DP direct transmission with USB solution. Detailed Implementation

[0015] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Unless otherwise specified, the embodiments and features in the embodiments of this application can be combined with each other. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0016] For details in the embodiments, please refer to Figures 1 to 5 .

[0017] Firstly, the following two modes are adopted in the existing technology to solve the problem of cross-board transmission of video and touch: Existing method 1. Serial deserialization scheme: such as Figure 4 As shown, the external interrupt is passed through by the GPIO pass-through function provided by the serial deserializer chip hardware, and the touch interrupt at the screen is passed through to the domain controller host to complete the touch function.

[0018] The serializer and deserializer are chips that convert video signals, GPIO levels, and low-speed I2C signals into FPD-Link / GMSL signals on the standard wiring harness. This IC itself has a transparent I / O function. When using the serializer, the deserializer will sample the changes in the terminal level of the touch IC, and then transmit the event to the serializer through the FPD-Link / GMSL signal on the vehicle wiring harness. The serializer then restores the level at the serializer end.

[0019] Throughout the entire process described above, the software in the SoC is unaware that the level change originates from a remote location, and therefore processes it as if the SoC itself had received a level signal change locally.

[0020] The complexity of the existing methods lies in the implementation of the serial deserialization chip, but there is a problem that serial deserialization chips are scarce and have high utility value.

[0021] Existing method 2. DP direct transmission with USB solution, such as Figure 5 As shown, conversion via USB or forwarding via MCU both rely on the USB protocol, requiring the addition of a corresponding MCU or USB conversion chip that supports the USB protocol.

[0022] This solution uses an additional USB-to-I2C chip to receive GPIO changes, convert them into USB interrupt type data packets, and send them to the host's USB host. Figure 5 In this process, the MCU detects GPIO changes and then reads the points, which is used to encapsulate the entire touch event into an interrupt-type HID reporting event and pass it to the host.

[0023] The aforementioned existing methods all transmit interrupt events entirely on another physical medium in the USB domain, and also add an extra chip.

[0024] However, the above solutions all have the following problems: (1) the serializer and deserializer chips are expensive; (2) an additional USB controller is introduced, which limits the selection range of the main control MCU, increases the cost, and occupies the USB port. Therefore, this application bypasses the existing serializer and deserializer or DP mode video transmission + USB transmission touch solution, uses the I2C over AUX function of the AUX interface in the DP protocol to transmit touch data, and uses HPD to transmit interrupt signals. From the perspective of physical interface, it fully complies with the DisplayPort standard definition and completes the transmission of touch data without adding an additional physical interface.

[0025] At this time, as Figure 1 and Figure 2 As shown in the figure, the method for transmitting external interrupts at the vehicle display screen using the DP extended protocol proposed in this embodiment of the invention specifically includes the following steps: Step L1. Predefine the aux gpio pending flag as bit 0 of AUX register 40Ch for the receiver to feed back an external interrupt to the source. Step L2. The remote device generates an interrupt. The specific interrupt method is not limited (high level, low level, high pulse, low pulse are all acceptable, as long as the remote device and the DP receiver agree on the triggering method). Step L3. The DP receiver IC is triggered by a local I / O interrupt, recognizing that the remote device has issued an interrupt request; Step L4. The DP receiver IC sets the DPCD register in the DP module of this device, the address DPCD SINK_SPECIFIC_IRQ, and sets the aux gpio pending flag; Step L5. The DP receiver IC notifies the DP source IC by pulling HPD low for 0.5-1ms; Step L6. The DP source IC reads DPCD SINK_SPECIFIC_IRQ to determine if there is an additional interrupt. If so, it reads the aux gpio pending flag to determine if an interrupt is triggered. Step L7. The DP source IC clears the above flags and then enters the predefined interrupt handler function registered to this interrupt to handle the business layer logic of the external interrupt; Step L8. If an external interrupt is still triggered after the DP source IC clears the flag, determine whether to re-trigger the interrupt and repeat steps L2 to L7.

[0026] In practical implementation, the system structure adopted by this invention is as follows: (1) DP source IC: The DP source chip is used to be responsible for the output of raw video data and to serve as the initiator of AUX signals. All AUX command requests are initiated by the DP source IC. During the execution of the above method, the DP source IC needs to read the aux gpio pending flag after reading DPCD_SINK_SPECIFIC_IRQ according to the custom requirements to determine whether there is an external interrupt. If there is an interrupt, the corresponding interrupt handling function on the host side is executed, such as the touch interrupt handling function. (2) DP receiver IC: The DP sink chip is used to receive video data. It serves as the response end of the AUX signal and responds to the corresponding AUX protocol according to the aux protocol definition.

[0027] During the execution of the above method, the DP sink chip needs to identify the interrupt of the remote interrupt-initiating device according to the predetermined configuration method (level edge, active high and low), and set the DPCD_SINK_SPECIFIC_IRQ flag in the internal dpcd register, as well as set the custom aux gpio pending flag, and then trigger the HPD interrupt according to the DP protocol standard. (3) Remote device: A device used to initiate an interrupt at a remote location. There are situations where interrupts can be initiated arbitrarily, such as touch chips or ADC chips.

[0028] It is important to clarify that, in the process of implementing the above method, the purpose of using remote devices is to enable various remote devices to interrupt functions, and it does not involve any modification to the remote devices themselves.

[0029] In this specific implementation, the code for register operations is set as follows: void dp_check_device_service_irq(struct dp_device *dp) / / HPD interrupt handler function { u8 val; int ret; ret = drm_dp_dpcd_readb(&dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR,&val); / / Read IRQ VECTOR if (ret<0 || !val) return; if (val&DP_SINK_SPECIFIC_IRQ) ​​ / / Check DPCD_SINK_SPECIFIC_IRQ { ret = drm_dp_dpcd_readb(&dp->aux,0x40c,&val); / / Read 0x40cif(ret == 0) { if(val&0x1) { / / Check bit0 handle_nested_irq(dp->aux.vgpio_dev->touch_virtual_irq); / / Interrupt handler function that triggers the system's internal virtual interrupt } } }} Furthermore, in further specific applications, the above-described method is executed based on the constructed system, which is used for the scene description of touch.

[0030] in: Touch transmission relies on two types of dependencies: external interrupts and I2C access. Currently, the hardware environment based entirely on the DP standard protocol achieves these two types of dependencies: (a) The I2C over AUX protocol defined in the DP standard protocol is used to complete the I2C access from the host to the touch device on the screen. (b) Extend the standard HPD interrupt function in the DP protocol and use the HPD interrupt function to transmit the touch interrupt signal to the host's SoC.

[0031] In scenarios where touch data is transmitted using the DP extension protocol: Use the interrupt pin of the touch IC as an external interrupt for the display screen that needs to transmit data; According to the existing interaction mechanism, the touch interrupt is transmitted to the SOC. After receiving the interrupt, the interrupt handling function in the SOC will read the touch reporting data of the DP receiver IC through the I2C over AUX protocol. At this time, the entire reporting process continues to loop after the touch IC interrupt is triggered.

[0032] At this point, the execution of the method in this application is compared with existing methods, and statistical analysis is performed on different processing of the same interruption state, as shown in Table 1 below: Table 1. Comparison of Scheme Analysis

[0033] Based on the analysis conclusions of the above schemes, such as Figure 3 As shown, the method for transmitting vehicle display screen interrupt signals to the host provided in the above embodiment has the main advantage of eliminating the need for serializers and deserializers widely used in vehicle systems, and eliminating the need to rely on USB channels to transmit external interrupt signals such as touch signals. It achieves the transmission of external interrupts from the vehicle display screen to the host simply by extending the DP AUX communication protocol layer. Furthermore, interrupt notification and data interaction can be completed using only a standard DisplayPort interface and wiring harness, without the use of additional non-standard connectors. By simplifying the hardware architecture and wiring design of the vehicle display system, it further reduces the connection complexity and hardware cost between the vehicle host and the display screen. In this case, it is not necessary to select a USB-enabled MCU or bridge chip (e.g., Figure 3 The FT260 in the system avoids the hardware overhead, driver development and compatibility issues caused by additional chips. It can reliably report and process screen interrupts by extending the protocol layer only on the existing DP protocol, which can improve system integration and stability, while shortening the development cycle. It is more suitable for automotive display scenarios with high requirements for cost, reliability and simple architecture.

[0034] It is understood that the system provided in the embodiments of the present invention corresponds to the method provided in the embodiments of the present invention, and the explanation, examples and beneficial effects of the relevant content can be referred to the corresponding parts of the above methods.

[0035] The communication bus mentioned in the above-mentioned electronic devices can be a standard bus for interconnecting peripheral components or an extended industrial standard structure bus, etc. This communication bus can be divided into address bus, data bus, control bus, etc.

[0036] The communication interface is used for communication between the aforementioned electronic devices and other devices.

[0037] The memory may include random access memory or non-volatile memory, such as at least one disk storage device. Optionally, the memory may also be at least one storage device located remotely from the aforementioned processor.

[0038] The processors mentioned above can be general-purpose processors, including central processing units, network processors, etc.; they can also be digital signal processors, application-specific integrated circuits, field-programmable gate arrays or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components.

[0039] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium accessible to a computer or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, an optical medium, or a semiconductor medium, etc.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0041] Furthermore, it should be noted that if any directional indication (such as up, down, left, right, front, back, etc.) is involved in the embodiments of the present invention, the directional indication is only used to explain the relative positional relationship and movement of each component in a specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0042] Furthermore, those skilled in the art should understand that in the actual use of the embodiments of this application, there may be preset thresholds used as the basis for judging the corresponding technical solutions. These thresholds are conventional technical means commonly used in the field to implement functions such as state judgment, condition recognition, and control logic switching. The specific values, setting basis, value selection methods, determination methods, and adjustment rules of the thresholds involved in this technical solution are all conventional technical choices that can be reasonably determined by those skilled in the art based on conventional technical factors such as actual application scenarios, system working states, characteristics of the detection object, hardware performance parameters, and functional requirements, through conventional experiments, calibrations, and debugging. The specific setting and adjustment of the aforementioned thresholds will not cause this technical solution to be unimplementable as a whole, nor will it affect the realization of the core concept and the achievement of the technical effects of this technical solution.

[0043] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, in the embodiments of this invention, "multiple" refers to two or more. Moreover, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

Claims

1. A method for transmitting external interrupts at an in-vehicle display screen using the DP extended protocol, characterized in that, include: S1. Predefine the Aux GPIO suspend flag as a dedicated flag bit in the AUX register for judging external GPIO interrupts, which is used by the receiving end to feed back external interrupts to the source end; S2. When a remote device issues an interrupt in a specified manner, the receiving end triggers a local GPIO interrupt to identify the interrupt request issued by the remote device. S3. After recognizing the interrupt request, the receiving end writes the interrupt valid flag to the DPCD SINK_SPECIFIC_IRQ address in the DPCD register through the self-device DP module, and then sets the Aux GPIO pending flag to 1; S4. The receiver pulls the HPD pin low and holds it for 0.5 to 1 ms before restoring it to a high level and notifying the source. S5. After the source detects the HPD low signal, it reads the DPCD SINK_SPECIFIC_IRQ address and determines whether there is an additional interrupt. If there is, it reads the interrupt judgment flag in the AUX register to determine whether it is an external GPIO interrupt. S6. The source clears the identifier from the above steps, and then calls the pre-registered external GPIO interrupt handling function to handle the business logic corresponding to the external GPIO interrupt.

2. The method for transmitting external interrupts at the vehicle-mounted display screen using the DP extended protocol as described in claim 1, characterized in that, If an external interrupt is still triggered after the source end clears the flag in step S6, the receiving end will detect the GPIO interrupt again and repeat steps S2 to S6 until the interrupt signal of the remote device is released.

3. The method for transmitting external interrupts at the vehicle-mounted display screen using the DP extended protocol as described in claim 1, characterized in that, The source end reads DPCD_SINK_SPECIFIC_IRQ and then reads the Aux GPIO suspend flag to determine if there is an external interrupt. If there is an interrupt, the corresponding interrupt handling function on the host side is executed.

4. The method for transmitting external interrupts at the vehicle-mounted display screen using the DP extended protocol as described in claim 1, characterized in that, The receiving end identifies the interrupt signal initiated by the remote end through the local GPIO according to the specified configuration method, sets the DPCD_SINK_SPECIFIC_IRQ flag and the Aux GPIO pending flag in the internal DPCD register, and then triggers the HPD interrupt according to the DP protocol standard.

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