CN-122027756-A - Dual-channel display synchronous switching method and system based on dynamic delay compensation

CN122027756ACN 122027756 ACN122027756 ACN 122027756ACN-122027756-A

Abstract

The invention provides a dual-channel display synchronous switching method and system based on dynamic delay compensation, and belongs to the technical field of display equipment. The method comprises the steps of initializing a high-definition video soft switching control chip through an I2C bus to generate two paths of virtual EDID, configuring a parameter pre-storing mode of a USB switching control chip, performing secondary scanning detection on a Host connection state by an MCU, comparing the current state with an initial state stored in an initialization stage, sending a state reading instruction to the USB switching control chip by the MCU, sending an EDID locking instruction to the high-definition video soft switching control chip by the MCU, sending an enabling signal to the high-definition video soft switching control chip by the MCU, adding a basic delay difference value at the time of T0, sending an enabling signal to the USB switching control chip, and executing HDMI channel soft switching to keep the continuity of HPD and AUX signals. The invention realizes synchronous switching of the two-way display channels, and has no problems of picture blocking and screen brightening in sequence.

Inventors

Dai Dingwei
LI JUN
LIU XING

Assignees

深圳市欣博跃电子有限公司

Dates

Publication Date: 20260512
Application Date: 20260318

Claims (10)

1. The dual-channel display synchronous switching method based on dynamic delay compensation is characterized by comprising the following steps of: Performing full-dimensional self-checking for MCU power-on, initializing a high-definition video soft switching control chip through an I2C bus to generate two paths of virtual EDID, configuring a parameter pre-storing mode of a USB (universal serial bus) to display control chip, and switching the MCU to a standby mode after confirming that the hardware of the high-definition video soft switching control chip and the USB to display control chip are ready; Triggering MCU interrupt response through a physical switching key, performing secondary scanning detection on the Host connection state by the MCU, comparing the current state with the initial state stored in the initialization stage, calculating a sending time reference of a dual-channel enabling signal if the Host connection state is stable, and otherwise, jumping to an abnormal processing stage; The MCU sends a state reading instruction to the USB display control chip, reads the display parameters of the target Host, sends an EDID locking instruction to the high-definition video soft switching control chip, locks the virtual EDID corresponding to the target Host, and detects a feedback signal; The MCU starts an internal high-precision timer, sets the time T0 as a time reference, transmits an enabling signal to the high-definition video soft switching control chip, transmits the enabling signal to the USB switching control chip at the time T0 plus a basic delay difference value time, counteracts the hardware response difference of the two channels through a time-sharing transmission strategy, and realizes synchronous triggering; And after receiving the enabling signal, the high-definition video soft switching control chip executes HDMI channel soft switching, keeps the HPD and AUX signals continuous, and reads the display parameters of the target Host after receiving the enabling signal by the USB conversion display control chip, thereby completing the dual-channel non-perception synchronous switching.
2. The dual-channel synchronous display switching method based on dynamic delay compensation according to claim 1, wherein initializing the high-definition video soft switching control chip through the I2C bus generates two paths of virtual EDIDs, and configures a parameter pre-storing mode of the USB transfer display control chip, comprising: the MCU sends a standardized initialization instruction to the high-definition video soft switching control chip through the I2C bus, wherein the standardized initialization instruction comprises a generation rule of virtual EDID and a parameter mapping relation with real EDID of the display; After receiving the standardized initialization instruction, the high-definition video soft switching control chip generates two paths of isolated virtual EDID, all parameters of the virtual EDID are matched with the real EDID of the external display one by one, no parameter deviation is ensured, and if the external display is replaced, the MCU reads the real EDID again and updates the virtual EDID; the MCU writes the generated double-path virtual EDID into a dedicated on-chip register of the high-definition video soft switching control chip, synchronously writes the double-path virtual EDID into a nonvolatile EEPROM, and is powered off and restarted after writing without repeated configuration; the MCU sends a special configuration instruction to the USB-to-display control chip, and a parameter pre-storing mode of the USB-to-display control chip is started; The fixed address section of the on-chip nonvolatile register of the USB-to-display control chip is designated as a special storage area for display parameters in the special configuration instruction, so that the classified independent storage of the display parameters is realized.
3. The method for synchronous switching of dual-channel display based on dynamic delay compensation according to claim 1, wherein comparing the current state with the initial state stored in the initialization stage, if the Host connection state is stable, calculating a transmission time reference of the dual-channel enable signal, otherwise, jumping to the exception handling stage, comprises: The MCU is internally provided with a state comparison judging logic for detecting the GPIO level, the dual hosts are normally connected into an initial stable state after the KVM docking station is electrified, if the Host connection state detected by the secondary scanning is consistent with the initial stable state, the state of the hosts is judged to be stable, the switching condition is met, and the subsequent normal switching flow is directly entered; if the Host connection state is found to be changed after comparison, the current switching condition is judged to be unsatisfied, the MCU jumps to an abnormal processing stage, and hardware parameter resetting and state calibration flows of the high-definition video soft switching control chip and the USB-to-display control chip are executed, so that the follow-up normal switching flow is not continued.
4. The dual-channel display synchronous switching method based on dynamic delay compensation according to claim 1, wherein the MCU sends a status reading instruction to the USB transfer display control chip, reads a display parameter of a target Host, sends an EDID locking instruction to the high-definition video soft switching control chip, and locks a virtual EDID corresponding to the target Host, and comprises: The MCU determines a target Host of the switching according to the switching instruction, and sends a state reading instruction to the USB display control chip; After the USB-to-display control chip receives the data, establishing data communication with a Host to be switched through a USB HID high-speed transmission protocol, and reading display parameters of the Host; After reading, storing all parameters into a fixed address section of an on-chip nonvolatile register of the USB transfer display control chip; the MCU sends an EDID locking instruction to the high-definition video soft switching control chip, wherein the EDID locking instruction comprises a virtual EDID identifier corresponding to the Host to be switched at this time; After receiving the EDID locking instruction, the high-definition video soft switching control chip performs hardware locking on the appointed virtual EDID, and prevents virtual EDID information from being accidentally refreshed or lost in the switching process.
5. The dual-channel synchronous display switching method based on dynamic delay compensation according to claim 1, wherein the MCU starts an internal high-precision timer, sets a time T0 as a time reference, sends an enable signal to the high-definition video soft switching control chip, and sends an enable signal to the USB transfer display control chip when a basic delay difference is added to the time T0, comprising: after receiving feedback signals of completion of state reading and completion of locking, the MCU sends a starting instruction to an internal high-precision timer; The high-precision timer takes the set time T0 as a time reference to count microsecond; When the count value of the high-precision timer reaches the time T0, the MCU sends a high-level pulse enabling signal to a switching enabling pin of the high-definition video soft switching control chip through a special GPIO push-pull output pin; The high-precision timer continuously counts in microsecond level after transmitting a high-level pulse enabling signal of the HDMI channel at the time T0; When the accumulated counting time length of the high-precision timer reaches the basic delay difference value, the MCU sends a high-level pulse enabling signal with the same specification to a switching enabling pin of the USB switching display control chip through another path of special GPIO push-pull output pin.
6. The dual-channel display synchronous switching method based on dynamic delay compensation according to claim 1, wherein the high-definition video soft switching control chip performs HDMI channel soft switching after receiving an enable signal, and keeps HPD and AUX signals continuous, comprising: After receiving a high-level pulse enabling signal sent by the MCU through a switching enabling pin, the high-definition video soft switching control chip executes HDMI channel soft switching operation without interrupting transmission of an HPD signal and an AUX signal; The HPD signal is a hot plug detection signal between the display and the host, so that continuous transmission of the HPD signal is maintained, the display confirms that the HDMI equipment is in a normal connection state, and the display is prevented from triggering re-identification due to the fact that the display detects the disconnection of the equipment; the AUX signal is used for EDID interaction and control instruction transmission, so that the AUX signal is kept communicated, and the parameter interaction of the virtual EDID is ensured to be normal all the time; the high-definition video soft switching control chip guides the virtual EDID data stream corresponding to the Host to be switched to the signal input port of the external display through the internal high-speed data stream routing module, and has no disconnection of a physical signal chain, so that microsecond-level rapid switching of the HDMI channel is realized.
7. The dual channel display synchronization switching method based on dynamic delay compensation of claim 1, further comprising: When the MCU detects the change of the Host connection state in the switching triggering stage or the channel switching executing stage, a switching pause instruction is sent, an EDID resetting instruction is sent to the high-definition video soft switching control chip, a register resetting instruction is sent to the USB switching display control chip, and the EDID resetting and the display parameter resetting are executed.
8. The dual channel display synchronization switching method based on dynamic delay compensation of claim 7, further comprising: when the execution of the reset instruction is completed, the MCU detects the Host connection state again, and after confirming that the state is stable, the MCU reenters the standby state and waits for triggering the switching instruction again; when the reset instruction fails to execute, the MCU prompts a fault through an abnormal indicator lamp on the equipment, and the current display channel state is reserved, so that the influence of the black screen on use is avoided.
9. The dual channel display synchronization switching method based on dynamic delay compensation of claim 7, further comprising: After the switching is finished, the MCU reads the state registers of the high-definition video soft switching control chip and the USB-to-display control chip according to a preset period, if the channel signal abnormality is detected, a reconnection instruction is sent to the corresponding chip, the synchronous error is calculated based on the switching data, and if the synchronous error exceeds a preset threshold value, the basic delay difference is dynamically optimized.
10. A dual channel display synchronization switching system based on dynamic delay compensation, characterized in that the dual channel display synchronization switching system comprises a control module, the control module comprising a memory, a processor and a computer program stored on the memory and executable on the processor, the processor executing the computer program to implement the dual channel display synchronization switching method based on dynamic delay compensation according to any one of claims 1-9.

Description

Dual-channel display synchronous switching method and system based on dynamic delay compensation Technical Field The invention relates to the technical field of display equipment, in particular to a dual-channel display synchronous switching method and system based on dynamic delay compensation. Background With the rapid development of multi-screen expansion, multi-host collaborative office, industrial operation and maintenance and other scenes, the dual-channel Display synchronous switching technology has become a core key technology of equipment such as a KVM (keyboard-video-mouse) docking station, a multi-screen office terminal and the like, wherein the dual-channel Display architecture combining an HDMI (high-definition multimedia interface) channel and a USB-to-Display channel is widely applied to various fields such as office, teaching and industrial control due to the characteristics of wide adaptability and strong expansion capability. The core requirement of the dual-channel display synchronous switching is to realize the non-perception switching and high synchronism in the switching process of the multi-host video source, and the time sequence of the dual-channel display channels in the switching process is required to be kept consistent, and meanwhile, the switching delay is shortened to the greatest extent, so that an MCU is mostly adopted in the industry as a master control unit to overall schedule the working mode of a switching chip, the channel switching is realized by controlling a switching enabling signal, but the precision and the switching efficiency of the dual-channel display synchronous switching are still faced with a plurality of technical challenges due to the influence of the hardware response characteristics and the signal transmission mechanism differences of different display channels, and become the optimization key point in the field. In the prior art, the dual-channel Display synchronous switching technology has the defects that firstly, the dual-channel switching of the traditional KVM equipment has no accurate delay compensation mechanism, the hardware response speed of the HDMI channel and the USB-to-Display channel has inherent difference, time sequence deviation is easy to occur during switching, picture tearing and window misplacement are caused, the problem is more prominent in a 4K high refresh rate scene, the visual experience is seriously deteriorated, secondly, the signal chain of a Display and a host is directly disconnected in the traditional hardware switching mode, the signal re-grabbing flow is triggered, the HDMI channel is easy to renegotiation of EDID, parameter re-enumeration occurs in the USB-to-Display channel, the process takes up to 30 seconds, the scene requirement of real-time switching cannot be met, and thirdly, a few schemes are provided with fixed delay compensation values, but the compensation parameters cannot be dynamically optimized according to the state of the host Display parameter and the external Display, the synchronization precision is difficult to guarantee, the situation that the host is plugged in the switching process, the state is changed in the switching process, the situation of the host is easy to cause switching failure, the equipment black screen is caused, and the system stability is insufficient. Disclosure of Invention The invention aims to provide a dual-channel display synchronous switching method and system based on dynamic delay compensation, which are used for solving the technical problems that the conventional dual-channel display switching technology has time sequence deviation, so that a picture is torn or a window is misplaced, the scene requirement of real-time switching cannot be met, and targeted exception handling logic is lacked. In order to achieve the above purpose, the invention provides a dual-channel display synchronous switching method based on dynamic delay compensation, which comprises the steps of performing full-dimension self-test on an MCU, initializing a high-definition video soft switching control chip through an I2C bus to generate two paths of virtual EDID, configuring a parameter pre-storing mode of a USB (universal serial bus) switching control chip, and switching the MCU to a standby mode after confirming that hardware of the high-definition video soft switching control chip and the USB switching control chip is ready; the MCU is used for triggering MCU interrupt response through a physical switching key, performing secondary scanning detection on a Host connection state, comparing the current state with an initial state stored in an initialization stage, calculating a sending time reference of a dual-channel enabling signal if the Host connection state is stable, otherwise jumping to an abnormal processing stage, sending a state reading instruction to a USB switching control chip, reading display parameters of a target Host, sending an EDID locking instruction to a high-definition video