TWI794958B - Display driving circuit and image and command synchronization method - Google Patents

Abstract

An image and command synchronization method applied to a display driving circuit is disclosed. The image and command synchronization method includes the following steps: (a) defining an area range of a command set in the image in advance; (b) determining whether the command is enabled and its type; (c) if a determination result of the step (b) is yes, the display driving circuit recognizing the command; and (d) before the display driving circuit transmits a next frame, executing the command to switch a state of the display driving circuit and transmitting the image.

Description

Display driving circuit and image and instruction synchronization method

The present invention is related to a display driving circuit, in particular to a display driving circuit and an image and command synchronization method applied to the display driving circuit.

In the process of dynamic image output of various display systems with display driver ICs and screens, as the functions of display driver ICs become more and more diversified, in some application scenarios (such as smart phones), the system side needs to send instructions ( Command) to the display driver IC, so that the display driver IC is in a specific display state, and at the same time, the system needs to send the processed specific image corresponding to this specific display state at a precise moment, so that the processed specific image The specific display state of the image and the display driver IC can take effect synchronously and be output to the screen for display/presentation, so as to achieve the expected display effect.

However, if the command and image data sent by the system cannot be synchronized, for example, the command and the image are staggered by N frames (N > 3), the final display effect on the screen cannot meet expectations, resulting in phenomena such as flickering or delay. Can be divided into the following two situations:

(1) As shown in Figure 1, the image data DAT sent by the AP at the system side is faster than the state switching command CMD, so that the memory RAM is switched from state A to state B first, but the display driver IC has not yet switched states and is still Maintained in state A, the possible reason is that the image data DAT output by the AP on the system side cannot be accurately controlled to start refreshing the image at the time corresponding to the state switching command CMD taking effect, causing the two to fail to take effect synchronously and the expected display effect cannot be obtained .

(2) As shown in Figure 2, the state switching command CMD sent by the AP on the system side is faster than the image data DAT, so that the display driving circuit IC is switched from state A to state B first, but the state of the memory RAM has not yet switched and is still Maintaining state A, the possible reason is that the image processing unit of the AP on the system side is too busy, resulting in a delay in the output of the image data DAT, resulting in the two not being able to take effect synchronously, and the expected display effect cannot be obtained.

Therefore, the present invention proposes a display drive circuit and an image and command synchronization method applied to the display drive circuit, which can ensure that the display drive circuit receives the state switching command and image data at the same time (within the same frame), so as to achieve image refresh. Responding synchronously with the switching state, so as to effectively avoid the unexpected display effect caused by the asynchronous display image content and display driving circuit state switching in the prior art.

A preferred embodiment of the present invention is a method for synchronizing images and commands applied to a display driving circuit. In this embodiment, the image and command synchronization method includes the following steps: (a) define in advance the range of the command set in the image; (b) determine whether the command is enabled and its type; (c) if step (b) ) is yes, the display drive circuit recognizes the command; and (d) before the display drive circuit transmits the next frame, execute the command to switch the state of the display drive circuit and transmit the image.

In one embodiment, if the judgment result of step (b) is negative, the status of the display driving circuit remains unchanged and the image is transmitted according to a normal process.

In one embodiment, the command is a state switching command, and the system side encrypts the command in a specific area of the image and transmits it to the display driving circuit synchronously.

In one embodiment, when the display driving circuit receives an image, the display driving circuit decodes instructions from a specific area of the image to control the subsequent switching sequence.

In one embodiment, the display driving circuit is coupled to the display unit, and in step (d), when the display driving circuit switches from the first state to the second state and transmits an image to the display unit at the same time, the display unit is in the second state Display the image.

In one embodiment, the specific area of the image corresponds to the non-active display area of the display unit.

In one embodiment, the non-effective display area is selected from at least one of a notch area, a rounded corner area, a blind hole area, and an under-screen fingerprint recognition area.

In one embodiment, the specific area of the image corresponds to the effective display area of the display unit.

In one embodiment, the effective display area is at least one data area of the status bar.

In one embodiment, step (a) further includes: using the area range defined in advance as the start/end position of the instruction set, and the start area of the instruction set adopts a specific data format, which includes the header, the first An instruction, a second instruction, . . . , a cyclic redundancy check.

Another preferred embodiment of the present invention is a display driving circuit for synchronizing images and commands. In this embodiment, the display driving circuit includes a definition unit, a judgment unit and a control unit. The definition unit is used to define in advance the area range of the instruction set in the image. The judging unit is coupled to the defining unit for judging whether the command is enabled and its type. The control unit is coupled to the judging unit. If the judging result of the judging unit is yes, the control unit recognizes the command and executes the command to switch the state of the display driving circuit and transmit the image before the display driving circuit transmits the next frame.

In one embodiment, if the judging result of the judging unit is negative, the control unit maintains the state of the display driving circuit and transmits images according to a normal process.

In one embodiment, the display driving circuit is coupled to the system side, and the command is a state switching command, and the system side encrypts the command in a specific area of the image and transmits it to the display driving circuit synchronously.

In one embodiment, when the display driving circuit receives an image, the display driving circuit decodes instructions from a specific area of the image to control the subsequent switching sequence.

In one embodiment, the display driving circuit is coupled to the display unit. When the display driving circuit switches from the first state to the second state and transmits the image to the display unit at the same time, the display unit displays the image in the second state.

In one embodiment, the specific area of the image corresponds to the non-active display area of the display unit.

In one embodiment, the non-effective display area is selected from at least one of a notch area, a rounded corner area, a blind hole area, and an under-screen fingerprint recognition area.

In one embodiment, the specific area of the image corresponds to the effective display area of the display unit.

In one embodiment, the effective display area is at least one data area of the status bar.

In one embodiment, the definition unit is also used as the start/end position of the instruction set according to the area range defined in advance, and the start area of the instruction set adopts a specific data format, which sequentially includes the header, the first instruction, the second Two instructions, ..., cyclic redundancy check.

Compared with the prior art, the display drive circuit and image and command synchronization method proposed by the present invention can encrypt the state switching command in a specific area in the image data and transmit it to the display drive circuit synchronously through the system side, and then the display drive circuit from the The state switching instruction is decoded from the image data to ensure that the display driving circuit can receive the instruction and image data at the same time (in the same frame), so as to achieve a synchronous response between image refresh and switching state, and avoid the process of switching state in the display driving circuit In this method, the unexpected display effect caused by the asynchronous display image content and the state of the display driving circuit can effectively solve the problems encountered in the prior art.

A preferred embodiment of the present invention is a method for synchronizing images and instructions. In this embodiment, the image and command synchronization method can be applied to a display driving circuit of an electronic device with a display function (such as a smart phone), and the display driving circuit can be coupled to the system side (such as an application operating system) and Between display units (such as display panels), but not limited thereto.

Please refer to FIG. 3 . FIG. 3 shows a flow chart of the image and command synchronization method in this embodiment. As shown in Figure 3, the image and command synchronization method may include the following steps:

Step S10: Defining in advance the area range of the instruction set in the image;

Step S12: judging whether the command is enabled and its type;

Step S14: If the judgment result of step S12 is yes, display the drive circuit identification instruction;

Step S16: Before the display drive circuit transmits the next frame, execute an instruction to switch the state of the display drive circuit and transmit an image; and

Step S18: If the judgment result of step S12 is negative, the status of the display driving circuit remains unchanged and the image is transmitted according to the normal process.

In practical applications, as shown in FIG. 4, the above command may be a state switching command CMD for switching the display driving circuit IC from state A to state B, and the system side AP encrypts the state switching command CMD in the image of state B. The data DAT is sent to the display driving circuit IC post-synchronously in the specific area K. As shown in FIG. 5 , when the display driving circuit IC receives the image data DAT of state B, the display driving circuit decodes the state switching command CMD from the specific area K of the image data DAT to control the subsequent switching sequence. Since the display drive circuit IC can completely control the response timing of the state switching command CMD and the image data DAT, the image data DAT and the state switching command CMD can be synchronously effective and output to the display unit for display/presentation, so as to achieve the desired display effect .

It should be noted that the specific area K of the above image data DAT may correspond to an effective display area or a non-effective display area of a display unit (such as a display panel).

As shown in Figure 6, if the specific area of the image corresponds to the non-effective display area of the display unit, it can correspond to the notch area, rounded corner area, blind hole area, and under-screen fingerprint recognition area of the display unit. at least one of them. As shown in FIG. 7, if the specific area of the image corresponds to the effective display area of the display unit, it may correspond to at least one data area (lines 1 to N) of the status bar of the display unit, which is passed through the design and status bar. Instruction sets with similar color/grayscale data can avoid obvious display differences and can clearly read/recognize instructions. For example, as shown in FIG. 8 , the state switching command CMD can be encrypted in a specific area in the image data corresponding to the notch area and the rounded corner area of the display unit, but not limited thereto.

Please refer to Fig. 9. Compared with the prior art, the command and image are prone to be out of sync. The system-side AP of the present invention encodes the state switching command CMD for switching the display driving circuit IC from state A to state B, and then adds it to the The specific area K of the image data DAT of the state B, and the image data DAT and the state switching command CMD are synchronously transmitted to the display driving circuit IC. When the display driving circuit IC receives the image data DAT, the display driving circuit IC will decode the state switching command CMD from the specific area K of the image data DAT. Since the display drive circuit IC can fully grasp the response timing of the state switching command CMD and the image data DAT, it can realize the state switching command CMD and the state switching command CMD to take effect synchronously and output to the display unit (such as a display panel) for display/presentation, thereby To achieve the expected display effect.

In practical applications, step S10 also includes: according to the area range defined in advance as the start/end position of the instruction set, and as shown in Figure 10, the start area of the instruction set adopts a specific data format, for example, it can be sequentially It includes a header (Header) HDR, a first command CMD1, a second command CMD2, . . . , a cyclic redundancy check (Cyclic Redundancy Check) CRC, but not limited thereto.

It should be noted that the key design points of the encryption and encoding of the state switching command CMD by the AP at the system side of the present invention may include but not limited to the following items:

(1) If the state switching command CMD is added to the non-effective display area, the R/G/B data of a single pixel can be represented by 00~FF, but not limited to this;

(2) If the state switching command CMD is added to the effective display area (such as the status bar), the command list can be customized according to the needs, for example: if the status bar is dark (lower gray scale), the R/ The grayscale values L0~L16 in the G/B data can correspond to 0~F commands; if the status bar is brighter (higher grayscale), the grayscale values in the R/G/B data of a single pixel are L240~L255 Can correspond to 0~F commands, but not limited to this; and

(3) When the system-side AP encrypts and encodes the state switching command CMD, further consideration needs to be taken to prevent the risk of being compressed by Vesa transmission. Therefore, the system-side AP can, for example, gray out the R/G/B data of a single pixel The level value L0 is encoded as a binary 0 and the gray level value L255 is encoded as a binary 1, but not limited thereto.

Another preferred embodiment of the present invention is a display driving circuit. In this embodiment, the display driving circuit is used to realize image and command synchronization.

As shown in FIG. 11 , the display driving circuit 1 can be coupled between the system end AP and the display unit (such as a display panel) PL. The system-side AP can encrypt instructions (such as state switching instructions) in a specific area of image data and transmit them to the display driver circuit 1 synchronously, so as to ensure that the display driver circuit 1 can receive instructions and images at the same time (in the same frame). like data.

The display driving circuit 1 may include a definition unit 10 , a judgment unit 12 and a control unit 14 . The defining unit 10 is used to define in advance the area range of the instruction set in the image. The judging unit 12 is coupled to the defining unit 10 for judging whether the command is enabled and its type. The control unit 14 is coupled to the judging unit 12 . If the judging result of the judging unit 12 is yes, the control unit 14 recognizes the command and executes the command to switch the state of the display driving circuit 1 and transmit the image before the display driving circuit 1 transmits the next frame. If the judging result of the judging unit 12 is negative, the control unit 14 keeps the state of the display driving circuit 1 unchanged and transmits images according to a normal process.

In practical application, the control unit 14 of the display driving circuit 1 decodes the state switching instruction from a specific area of the image data to control the subsequent switching sequence. Since the display drive circuit 1 can fully grasp the response timing of the state switching command and the image data, it can realize that the state switching command and the state switching command take effect synchronously and output to the display unit (such as a display panel) PL for display/presentation, so as to achieve the expected display effect.

It should be noted that the specific area of the image data added by the state switching instruction may correspond to the non-effective display area of the display unit PL, such as at least one of the notch area, rounded corner area, blind hole area, and under-screen fingerprint recognition area. One, but not limited thereto; this specific area can also correspond to the effective display area of the display unit, such as at least one data area (1 to N) of the status bar, which can be displayed through the design and the color/gray of the status bar Instruction sets with similar order data can avoid obvious display differences and can clearly read/recognize instructions, but not limited thereto.

Compared with the prior art, the display drive circuit and image and command synchronization method proposed by the present invention can encrypt the state switching command in a specific area in the image data and transmit it to the display drive circuit synchronously through the system side, and then the display drive circuit from the The state switching instruction is decoded from the image data to ensure that the display driving circuit can receive the instruction and image data at the same time (in the same frame), so as to achieve a synchronous response between image refresh and switching state, and avoid the process of switching state in the display driving circuit In this method, the unexpected display effect caused by the asynchronous display image content and the state of the display driving circuit can effectively solve the problems encountered in the prior art.

S10~S18: steps

AP: system side

CMD: state switching command

DAT: image data

RAM: memory

IC: display driver circuit

K: specific area

HDR: header

CMD1: the first command

CMD2: the second command

CRC: Cyclic Redundancy Check

1: Display drive circuit

10: Define the unit

12: Judgment unit

14: Control unit

FIG. 1 is a schematic diagram of the prior art that cannot take effect synchronously because images are faster than commands.

FIG. 2 is a schematic diagram of the prior art that cannot take effect synchronously because commands are faster than images.

FIG. 3 is a flowchart of a method for synchronizing images and commands in an embodiment of the present invention.

FIG. 4 is a schematic diagram of encrypting a state switch command in a specific area of image data by the system side.

FIG. 5 is a schematic diagram showing a state switching command decoded by a display driving circuit from a specific area of image data.

FIG. 6 is a schematic diagram illustrating that a specific area of image data corresponds to an inactive display area of a display unit.

FIG. 7 is a schematic diagram illustrating that a specific area of image data corresponds to an effective display area of a display unit.

FIG. 8 is a schematic diagram illustrating that the state switching command is encrypted in a specific area in the image data and it corresponds to the notch and the rounded area of the display unit.

FIG. 9 is a schematic diagram of synchronously validating image data and state switching commands in the present invention.

FIG. 10 shows a schematic diagram of a specific data format used in the initial area of the instruction set.

FIG. 11 is a functional block diagram of a display driving circuit in another embodiment of the present invention.

S10~S18: steps

Claims (20)

A method for synchronizing an image and an instruction, applied to a display drive circuit, comprising the following steps: (a) defining in advance the range of the instruction set in the image; (b) judging whether the instruction is enabled (Enable) and its type; (c) If the judgment result of step (b) is yes, the display driving circuit recognizes the instruction; and (d) before the display driving circuit transmits the next frame, execute the instruction to switch the state of the display driving circuit and transmit the image. The image and command synchronization method as described in Claim 1, wherein if the judgment result of step (b) is negative, the state of the display driving circuit remains unchanged and the image is transmitted according to a normal process. The image and command synchronization method as described in Claim 1, wherein the command is a state switching command, and the system encrypts the command in a specific area of the image and transmits it synchronously to the display driving circuit. The image and command synchronization method as described in claim 3, wherein when the display drive circuit receives the image, the display drive circuit decodes the command from the specific area of the image to control the subsequent switching sequence . The image and command synchronization method as described in Claim 1, wherein the display driving circuit is coupled to the display unit, and in step (d), when the display driving circuit switches from the first state to the second state and simultaneously transmits the image When the image is sent to the display unit, the display unit displays the image in the second state. The image and instruction synchronization method as described in claim 3, wherein the image The specific area corresponds to the non-active display area of the display unit. The image and command synchronization method according to claim 6, wherein the non-effective display area is selected from at least one of a notch area, a rounded corner area, a blind hole area, and an under-screen fingerprint recognition area. The image and command synchronization method as claimed in claim 3, wherein the specific area of the image corresponds to an effective display area of a display unit. The method for synchronizing images and instructions according to Claim 8, wherein the effective display area is at least one data area of the status bar. The method for synchronizing images and instructions as described in claim 1, wherein step (a) further includes: using the area range defined in advance as the start/end position of the instruction set, and the start area of the instruction set uses A specific data format, which sequentially includes a header (Header), a first instruction, a second instruction, . . . , a cyclic redundancy check (CRC). A display drive circuit, used to realize the synchronization of images and instructions, the display drive circuit includes: a definition unit, used to define in advance the area range of the instruction set in the image; a judgment unit, coupled to the definition unit, for judging Whether the command is enabled (Enable) and its type; and the control unit is coupled to the judging unit, if the judging result of the judging unit is yes, the control unit recognizes the command and transmits the next frame before the display drive circuit , execute the instruction to switch the state of the display driving circuit and transmit the image. The display driving circuit as described in claim 11, wherein if the judgment If the judgment result of the unit is negative, the control unit maintains the state of the display driving circuit and transmits the image according to the normal process. The display driving circuit as described in claim 11, wherein the display driving circuit is coupled to the system end, the command is a state switching command and the system side encrypts the command in a specific area of the image and transmits it synchronously to the Display drive circuit. The display driving circuit according to claim 13, wherein when the display driving circuit receives the image, the display driving circuit decodes the command from the specific area of the image to control subsequent switching timing. The display driving circuit as described in claim 11, wherein the display driving circuit is coupled to a display unit, and when the display driving circuit switches from the first state to the second state and simultaneously transmits the image to the display unit, the display unit The image is displayed in the second state. The display driving circuit according to claim 13, wherein the specific area of the image corresponds to an inactive display area of a display unit. The display driving circuit according to claim 16, wherein the non-effective display area is selected from at least one of a notch area, a rounded corner area, a blind hole area, and an under-display fingerprint recognition area. The display driving circuit according to claim 13, wherein the specific area of the image corresponds to an effective display area of a display unit. The display driving circuit according to claim 18, wherein the effective display area is at least one data area of the status bar. The display driving circuit as described in claim 11, wherein the definition list The element is also used as the start/end position of the instruction set according to the area range defined in advance, and the start area of the instruction set adopts a specific data format, which includes the header (Header), the first instruction, the second Instructions, ..., Cyclic Redundancy Check (CRC).

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