KR20060072174A - Display data transmission device and display data transmission method for the same - Google Patents

Abstract

A first frame buffer storing image information currently being displayed, an image information input unit for receiving new image information to replace image information stored in the first frame buffer, and a counter, and including image information of the first frame buffer and a new one. By comparing the image information pixel by pixel, the value of the counter is increased when the pixels of both image information have the same pixel data, and when the pixels of both the image information have different pixel data, the value of the counter and the new image information are increased. The display data transmission apparatus includes a frame comparator for outputting new pixel data, and a data transmitter for classifying the new pixel data and the counter value output by the frame comparator. Thus, by reducing the amount of display data transmitted, electromagnetic interference characteristics and current consumption can be reduced.

Description

Display data transmission device and display data transmission method {DISPLAY DATA TRANSMISSION DEVICE AND DISPLAY DATA TRANSMISSION METHOD FOR THE SAME}             

Fig. 1 is a block diagram showing an example of the configuration of a host and display driver in the prior art.

2 is a block diagram illustrating a system interface applied to the display data transmission method of the present invention.

3 is a timing diagram illustrating a signal transmission method of a system interface applied to the display data transmission method of the present invention.

4A is a timing diagram illustrating a display data transmission method of the prior art.

  4B is a timing diagram illustrating a display data transmission method of the present invention.

5 is a block diagram showing a configuration example of a display data transmission device of the present invention.

Explanation of symbols on the main parts of the drawings

80: display data transmission device

81: first frame buffer 82: second frame buffer                 

83: frame comparison unit 84: input unit

85: comparison unit 86: counter

87: output unit 88: data transmission unit

The present invention relates to an apparatus and method for transmitting display data, and more particularly, to an apparatus and method for transmitting data that can reduce electromagnetic interference characteristics and current consumption by reducing the amount of transmitted display data.

Higher data band widths in communications and display applications necessitate high-speed data transfer between chips, boards or systems. In the area where high-speed data transmission is required, as the operating frequency increases, the characteristics of electromagnetic interference (EMI) become important design elements.

In particular, among these, the display area has a higher color-depth and resolution per pixel to be represented, and thus, a high necessity for high-speed data transmission is required, and EMI and current consumption characteristics are very important.

1 is a block diagram showing a configuration example of a host and display driver of the prior art.

Referring to FIG. 1, transmission and reception of display data are performed by a host 10 transmitting display data and a display driver 30 receiving and displaying display data, respectively.

The host 10 may be, for example, a video board of a PC. In the case of an embedded system such as a PDA and a mobile communication terminal, the host 10 includes a micro controller unit (MCU) and the like, and transmits display data to the display driver 30. FIG. 1 illustrates an example of an embedded system, and the host 10 in FIG. 1 is a generic name of devices for generating and transmitting display data including an MCU.

Referring to FIG. 1, the host 10 is connected to the MCU 11 to receive a bus interface 12 that receives image information to be output, and is connected to the display driver 30 in series or parallel with the display driver 30 under the control of the MCU. And a timing controller 14 for generating timing information such as a synchronization signal such as a vertical synchronization signal and a horizontal synchronization signal.

The display driver 30 may be, for example, a liquid crystal display (LCD) driver.

Referring to FIG. 1, the display driver 30 is connected in series or in parallel with the host 10 to synchronize the display data received from the host 30 and the host interface 31 receiving the display data and timing information to be output. The timing controller 32 may be configured to supply the digital analog converter 33 to the digital analog converter 33, the digital analog converter 33 to supply the display voltage to the display panel 34, and the display panel 34.

The host interface 31 is an interface for receiving display data connected in series or in parallel with the host 10.

In this case, the transmission method of the display data between the host 10 and the display driver 30 may vary depending on whether the display driver 30 includes a memory serving as a frame buffer. Can be.

That is, when the display driver 30 does not have a frame buffer, the host 10 must continuously transmit image information to be displayed through the display driver 30 at predetermined time intervals.

  On the other hand, when the display driver 30 includes the frame buffer, the image information currently output in the frame buffer memory is stored, and thus, in the case of the still image, the image information does not need to be sent again.

However, even when the display driver 30 includes the frame buffer as described above, if a part of the image to be displayed is changed, for example, even if one pixel is changed, the entire image information must be transmitted again. Therefore, although the amount of information required for screen update is only a very small amount, since data transmission is repeatedly performed for the entire image, there is a problem in that the EMI characteristic is deteriorated and inefficient current consumption occurs.

      SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide a display data transmission apparatus capable of reducing electromagnetic interference characteristics and current consumption by reducing the amount of display data transmitted.

Another object of the present invention is to provide a display data transmission method capable of reducing electromagnetic interference characteristics and current consumption by reducing the amount of display data transmitted.

In order to achieve the above object, the present invention includes a first frame buffer storing image information currently being displayed, an image information input unit receiving new image information to replace image information stored in the first frame buffer, and a counter. The image information of the first frame buffer and the new image information are compared in units of pixels, and when the pixels of both frame buffers have the same pixel data, the value of the counter is increased, and the pixels of both frame buffers are different. In the case of having the pixel data, a frame comparator for outputting the value of the counter and new pixel data of the new image information, and a data transmitter capable of distinguishing and transmitting the counter pixel and the new pixel data output from the frame comparator Including a display data transmission device to provide.                     

Here, the display data transmission device further includes a second frame buffer for receiving new image information from outside from which the image information stored in the first frame buffer is replaced, and the image information input unit is provided from the second frame buffer. It may be configured to receive new image information.

Herein, the frame comparison unit sequentially receives pixel data of pixels corresponding to each other from the first frame buffer and the image information input unit, and a comparison unit comparing pixel data of pixels corresponding to each other input through the input unit. A counter that increases in value when the comparison unit determines that the pixel data of the corresponding pixels is the same; and when the comparison unit determines that pixel data of the corresponding pixels is different, And an output unit for outputting new pixel data of the image information input unit.

Here, when the counter value input from the frame comparator is 0, the data transmitter transmits the new pixel data of the new image information received from the frame comparator to the outside and receives the input from the frame comparator. When the counter value is not 0, the counter value and new pixel data of the new image information received from the frame comparator may be transmitted to the outside.

In order to achieve the above object, the present invention provides a method of storing image information currently being displayed, receiving new image information to replace image information currently being displayed, the image information currently displayed and the new image information. Sequentially comparing pixel data of the corresponding pixels of the image information, increasing the predetermined counter value when the pixel data of the corresponding pixels is the same, and not the same pixel data of the corresponding pixels. And outputting the predetermined counter value and the pixel data of the new image information, and separately transmitting the predetermined counter value and the pixel data of the new image information. .

      Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram illustrating a system interface applied to the display data transmission method of the present invention.

In a typical embedded system, display data transmission between a host side and a display driver is performed through a serial communication method such as a serial peripheral interface (SPI) or a parallel communication method consisting of a plurality of wires.

Referring to FIG. 2, the interface between the display controller 13 of the host 10 and the host interface 31 of the display driver 30 is a register selection signal line (hereinafter referred to as RS signal) and write signal line (hereinafter referred to as “interface”. WR signal) and a data line (hereinafter, a DATA signal).                     

The RS signal RS is a signal for selecting a register in the display driver, and when the RS signal falls to 'low', the display driver is driven by an index value transmitted through a data line DATA configured in series or in parallel. The register is selected.

The WR signal WR is a strobe signal falling to 'low' when writing data from the display controller 13 to the host interface 31, and is serial when the WR signal WR falls to 'low'. Alternatively, data is transferred to the display driver through data transmission lines configured in parallel.

On the other hand, the above-described interface method is only mentioned one embodiment of the interface method widely used in a general embedded system, and other interface methods (for example, I2C) existing, or as an interface method for performing a corresponding purpose in the future It will be apparent to one of ordinary skill in the art that the present invention may be replaced.

3 is a timing diagram illustrating a signal transmission method of a system interface applied to the display data transmission method of the present invention.

Referring to FIG. 3, a transmission scheme of display data through the RS signal line, the WR signal line, and the data line illustrated in FIG.

The RS signal RS stays 'high' (51) and falls to a 'low' state when a register index value for selecting a register on the display driver side is transmitted through the data line 52 (53). . That is, depending on whether the RS signal is in the 'high' state or the 'low' state, it is determined whether the data transferred through the data line is a register index value or data to be written to a designated register.

Therefore, when the RS signal is 'low' (53), the signal 52 transmitted through the data line is recognized as the index value of the register. On the other hand, when the RS signal becomes 'high' (51), the signal 53 transmitted through the data line is recognized as data to be written to the register.

On the other hand, the WR signal WR serves as a strobe signal as described above. Data is written in a state where the WR signal has fallen low. On the other hand, in the case of a synchronous clock interface method in which a data line includes only one line, the WR signal may serve as a synchronous clock signal.

4A and 4B are timing diagrams for comparing the display data transmission method according to the display data transmission method of the present invention with the display data transmission method of the prior art.

4A is a timing diagram illustrating a display data transmission method of the prior art.

Referring to FIG. 4A, the display data transmission method according to the related art is index information INDEXX for specifying the X position of the display data, X position data DATAX, index information INDEXY for specifying the Y position, and the Y position. Data DATAY is preceded, and data 61, 62 and 63 constituting one frame are sequentially transmitted.

4A illustrates display data transmission in the case of a display device including a display panel including 240 columns and 320 rows, for example, in which pixel data values corresponding to a total of 76800 pixels are sequentially transmitted to the display driver. Doing.

 As already mentioned, even when the display driver has its own frame buffer memory, if any part of the contents of the currently displayed image information is changed, the entire image information must be transmitted again. In fact, the amount of information required to update the screen is only a very small amount, but since data transmission is repeatedly performed for the entire image, this means that pixel data corresponding to, for example, 76800 pixels is transmitted again.

4B is a timing diagram illustrating a display data transmission method of the present invention.

Referring to FIG. 4A, the display data transmission method of the present invention provides the index information INDEXX for specifying the X position of the display data, the X position data DATAX, the index information INDEXY for specifying the Y position, and the Y position. The preceding is the same as the data DATAY.

However, the display data transmission method of the present invention sequentially compares image information currently displayed with image information to be newly displayed on a pixel basis, and does not transmit pixel data when the corresponding pixel data is the same.

Instead of transmitting the pixel data, the host side increases the count value when the pixel data of the corresponding pixels is the same (71, 71). When the pixel data of the corresponding pixels ends in the same section and the pixel data of the corresponding pixels meet in different sections, the counted count value is written to a predetermined register (75, 76).

When the section in which the pixel data of the pixels corresponding to each other continue is continued, the pixel data of the image information to be newly displayed is sequentially transmitted to the display driver (77). That is, after the pixel data 71 and 72 of the 0 th pixel and the first pixel of the image information are transmitted, 150 pixels indicate that the same pixel data as the conventional pixel is maintained (75 and 76). Thereafter, the data is sequentially transmitted again from the pixel data of the 151st pixel (77).

5 is a block diagram showing a configuration example of a display data transmission device of the present invention.

Referring to FIG. 5, the display data transmission device 80 of the present invention includes a first frame buffer 81, a second frame buffer 82, a frame comparator 83, and a data transmitter 88. It is composed.

The first frame buffer 81 is a frame buffer that stores image information currently being displayed, and the second frame buffer 82 is new image information to replace image information stored in the first frame buffer 81. The frame buffer that stores the.

Therefore, the MCU 11 included in the host writes new image information into the second frame buffer 82. On the other hand, the display data transmission device 80 illustrated in FIG. 5 exemplifies only a configuration having a second frame buffer, but omits the configuration of the second frame buffer and directly displays new image information from the MCU 11 or the like. It may take a configuration that is directly input to the frame comparison unit 83 receives the input.

The frame comparator 83 compares the image information of the first frame buffer 81 with the image information of the second frame buffer 82 or new image information input from the outside in units of pixels.

In more detail, the frame comparator 83 receives an input unit 84 and an input unit 84 that sequentially receive pixel data of pixels corresponding to each other from the first frame buffer 81 and the second frame buffer 82. It may be configured to include a comparison unit 85, a counter 86 and an output unit 87 for comparing the pixel data received from the.

In the comparison unit 85 of the frame comparison unit 83, in the case of a pixel having the same pixel data, only the count of pixels having the same data is increased, and new pixel data is not output. On the contrary, when the section of the pixel having the same pixel data ends and encounters a pixel having different pixel data, the comparator 85 outputs the new pixel data through the output unit 87, and at the same time, the counter 86 Outputs the counted count value through the output unit 87.

When the count value output from the output unit 87 of the frame comparator 83 is 0, the data transmission unit 88 sequentially outputs the received new pixel data to the outside. In addition, when the count value output from the output unit 87 of the frame comparator 83 is not zero, the data transfer unit 88 has a predetermined promise register on the display driver side as described with reference to FIG. 4B. A count value is transmitted to the controller and a new pixel data is sequentially output again.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

According to the present invention as described above, in the apparatus and method for transmitting display data, it is possible to reduce the amount of display data to be transmitted can reduce the electromagnetic interference characteristics and current consumption.

Claims (6)

A first frame buffer storing image information currently being displayed; An image information input unit configured to receive new image information to replace image information stored in the first frame buffer; A counter, and comparing the image information of the first frame buffer with the new image information on a pixel-by-pixel basis, when the pixels of both image information have the same pixel data, increasing the value of the counter, and A frame comparator for outputting new pixel data of the counter value and the new image information when the pixels have different pixel data; And And a data transmitter configured to distinguish and transmit the value of the counter and the new pixel data output by the frame comparator. The method of claim 1, The display data transmission device And a second frame buffer configured to receive new image information from outside from which the image information stored in the first frame buffer is replaced, wherein the image information input unit receives new image information from the second frame buffer. Display data transmission device. The method of claim 1, The frame comparison unit An input unit which sequentially receives pixel data of pixels corresponding to each other from the first frame buffer and the image information input unit; A comparison unit for comparing pixel data of pixels corresponding to each other input through the input unit; A counter for increasing a value when the comparing unit determines that the pixel data of the corresponding pixels are identical; And And determining that the pixel data of the corresponding pixels are different from each other by the comparing unit, and including an output unit which outputs a value of the counter and new pixel data of the image information input unit. The method of claim 1, The data transmission unit When the counter value received from the frame comparator is 0, new pixel data of the new image information received from the frame comparator is transmitted to the outside, and the counter value received from the frame comparator is not 0. And transmitting the new pixel data of the new image information received from the counter value and the frame comparator to the outside. Storing the image information currently being displayed; Receiving new image information to replace the currently displayed image information; Sequentially comparing pixel data of pixels corresponding to the currently displayed image information with the new image information; Increasing a predetermined counter value when the pixel data of the corresponding pixels are the same; Outputting pixel data of the predetermined counter value and the new image information when the pixel data of the corresponding pixels are not the same; And And dividing and transmitting the predetermined counter value and pixel data of the new image information. The method of claim 5, Transmitting the predetermined counter value and the pixel data of the new image information separately. If the counter value is 0, transmitting pixel data of the new image information to the outside; And And transmitting the counter value and pixel data of the new image information to the outside when the counter value is not zero.

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