JP2010169753A - Two-screen display output system - Google Patents

Abstract

A two-screen display output system capable of controlling screen display of two displays with a single graphic display controller.
A two-screen display output system includes a storage unit 230 that temporarily stores image data output from a GDC 20, a frequency dividing unit 210 that divides a reference clock by a half frequency, and a frequency dividing frequency. A first reading unit 240 that reads first image data of a portion related to the display 50, a first output unit 280 that outputs the first image data together with a synchronization signal, and frequency division after the first reading unit A second reading unit 250 that reads the second image data of the portion related to the display 60 at a frequency, a delay unit 270 that delays the synchronization signal output from the GDC 20, and a frequency division and delay unit for dividing the second image data And a second output unit 290 for outputting together with the synchronization signal delayed by a predetermined time at 270.
[Selection] Figure 1

Description

  The present invention relates to a two-screen display system that has two displays and displays each screen.

  Some devices that display a screen such as a car navigation system have two displays, which are configured to display different images or consecutive images. FIG. 5 is a block diagram showing a schematic configuration of a conventional two-screen display output system. The two-screen display output system has two displays 50 and 60. Each display has a graphic display controller (GDC), and each GDC of the GDCs 20 and 30 transfers RGB screen data, a synchronization signal for synchronizing two displays, and screen data per scanning line. A reference clock signal as a reference is generated separately and output to the display.

  However, in the conventional two-screen display output system, a memory such as a ROM or a RAM for storing screen data is required for each GDC, and the same screen data has to be stored in each memory. Furthermore, the CPU 10 that controls it requires complex software control for the two GDCs in order to synchronize the two screen data.

  By the way, in a display device that displays one display divided into two screen areas, the same data bus is transferred by transferring two unsynchronized reference clocks for the purpose of reducing unnecessary radiation noise and reducing the cost by reducing terminals. A display device has been proposed in which screen data to be transferred is alternately allocated to two screen areas and a dual scan method is realized in a pseudo manner (see, for example, Patent Document 1).

  However, in the two-screen display output system, conventionally, a method for selectively distributing screen data for two screens with one GDC as described above has not been disclosed.

JP 2003-186449 A (page 3 to page 4, FIG. 1)

  The present invention has been made in view of the above-described circumstances, and its purpose is to generate and output screen data combining two screens by GDC, and distribute the screen data to two displays by a screen distributor. It is intended to provide a two-screen display output system that can control screen display related to two displays with one GDC.

In order to achieve the above-described object, a two-screen display output system according to the present invention is characterized by the following (1).
(1) the first display;
A second display,
A display controller for sending image data obtained by combining two screen image data related to the screen display of the first display and the second display, and a reference clock and a synchronization signal for controlling the display of the image data;
A storage unit that stores the image data output from the display controller, a frequency dividing unit that generates a divided frequency obtained by dividing the reference clock by a half frequency, and the storage unit that stores the frequency Of the image data, a first reading unit that reads first image data to be output to the first display at the divided frequency, and the first image data read by the first reading unit. A first output unit that outputs to the first display together with the synchronization signal; and second image data to be output to the second display among the image data stored in the storage unit. A second reading unit that reads the divided frequency after the reading unit, a delay unit that delays the synchronization signal output from the display controller, and a second reading unit that reads the synchronization signal. A screen divider having a second output section for outputting the second image data to the second display with a predetermined time delay to the synchronizing signal in the reference clock and the delay unit of the divided frequency,
Be provided.

  According to the two-screen display output system having the configuration (1), it is possible to control screen display related to two displays with one display controller.

According to the present invention, since the control related to the screen display of two displays is performed by one GDC, the GDC and its memory (ROM / RAM) can be reduced, and the component and mounting costs can be reduced by simplifying the component configuration. Can be reduced.
In addition, since the system configuration is simplified, the load on the CPU software that controls the GDC is reduced, and the system can be provided at low cost.

  The present invention has been briefly described above. Further, details of the present invention will be further clarified by reading through the modes for carrying out the invention described below with reference to the accompanying drawings.

The block diagram which shows schematic structure of the 2 screen display output system in embodiment of this invention Schematic diagram conceptually showing how the combined two screen data are distributed by the screen distributor The functional block diagram which shows schematic structure of the screen divider | distributor of the two-screen display output system in embodiment of this invention Functional timing chart of screen distributor of dual-screen display output system in an embodiment of the present invention A block diagram showing a schematic configuration of a conventional two-screen display output system

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

  FIG. 1 is a block diagram showing a schematic configuration of a two-screen display output system in an embodiment of the present invention. The two-screen display output system mainly includes a CPU 10, a GDC 20, a screen distributor 40, displays 50 and 60, and the like.

  The CPU 10 is a control unit that performs overall control of the operation of the two-screen display output system. The GDC 20 is a graphic display controller, and includes a ROM 21 and a RAM 22 that store screen data to be displayed on the displays 50 and 60. The RGB screen data is generated by the GDC. In the present invention, the GDC 20 combines the screens displayed on the two displays as shown in FIG. 2 and outputs the combined screens to the screen distributor 40 described later. The GDC 20 also generates and outputs a synchronization signal sync for synchronizing the two displays together with the screen data and a reference clock signal clock serving as a reference for transferring the screen data.

  The screen distributor 40 is a control unit that is located between the GDC 20 and the displays 50 and 60 and distributes the screen data that is a combination of the input two screens so that each screen is displayed. The screen distributor 40 has a first output unit output-1 and a second output unit output-2, and the distributed images are output from the respective output units as shown in FIG.

  FIG. 3 is a functional block diagram showing a schematic configuration of the screen distributor 40 of the two-screen display output system in the embodiment of the present invention. The screen distributor 40 mainly receives an input unit 200 to which a reference clock signal clock is input, a frequency dividing unit 210 that divides the input reference clock into a half frequency, and RGB screen data. Input unit 220, storage unit 230 for temporarily storing input screen data, first reading unit 240 for reading screen data to be transferred to the first output unit, and screen data to be transferred to the second output unit The second reading unit 250 for reading the data, the input unit 260 for receiving the synchronization signal sync, the delay unit 270 for delaying the inputted synchronization signal, the screen data output from the first reading unit 240, and the frequency division The first output unit 280 to which the frequency reference clock signal clock1 and the synchronization signal sync1 are input, the screen data output from the second reading unit 250, the frequency division reference clock signal clock2 and the synchronization signal sync2 are input. The second output unit 290 is configured.

  Next, the screen display operation of the two-screen display output system configured as described above will be described. Hereinafter, screen data displayed on the display 50 via the first output unit 280 is referred to as screen 1, and screen data displayed on the display 60 via the second output unit 290 is referred to as screen 2.

  FIG. 4 is a functional timing chart of the screen distributor of the two-screen display output system in the embodiment of the present invention. First, screen data 301 to be displayed on the displays 50 and 60 together with the reference clock 300 is input from the GDC 20 to the input unit 220. The screen data is temporarily stored in the storage unit 230, and the screen data of the screen 1 is read into the first reading unit 240. In the example of FIG. 4, screen data 303 from D0 to D4 is written into the internal RAM corresponding to 1 to 5 of the write address counter 302.

  The reference clock 300 input to the input unit 200 is frequency-divided by a half frequency by the frequency dividing unit 210 and transferred to the first and second reading units 240 and 250, so that the first reading unit 240 reads the partial data related to the screen 1 with the divided reference clock 306 (clock1), and outputs it to the first output unit 280 together with clock1 and the synchronization signal 309 (sync1). In the example of FIG. 4, screen data 308 of D0 to D4 corresponding to 1 to 5 of the read address counter 307 is output.

  On the other hand, the screen data of the screen 2 once stored in the storage unit 230 is read into the second reading unit 250. In the example of FIG. 4, screen data 305 from D5 to D9 is written into the internal RAM corresponding to 1 to 5 of the write address counter 304.

  Thereafter, the second reading unit 250 reads the partial data related to the screen 2 with the divided reference clock 306 (clock 2), and outputs the second output together with the clock 2 and the synchronization signal 312 (sync 2) delayed by the delay unit 270. Output to the unit 290. In the example of FIG. 4, screen data 311 of D5 to D9 corresponding to 1 to 5 of the read address counter 310 is output. Since the output is performed in units of screen data per scanning line, the data of the screen 1 and the screen 2 are displayed on the displays 50 and 60, respectively, by repeating the above procedure.

  As described above in detail, according to the two-screen display output system of the present invention, the screen data of the two screens combined by the GDC 20 is displayed on the screen 1 and the display 60 displayed on the display 50 by the screen distributor 40. Since it is appropriately distributed to the screen 2, display control of two screens can be performed with one GDC. By realizing the functional circuit of the screen distributor with LSI (PLD), it is possible to reduce the cost in terms of component configuration and mounting.

  The two-screen display output system of the present invention has an effect of reducing parts and mounting costs and can provide the system at a low cost, and is useful in a display device that displays a plurality of screens such as a car navigation system.

10 CPU
20,30 GDC
21,31 ROM
22, 32 RAM
40 Screen distributor 50, 60 Display 100 Dual screen display output system 200 Reference clock input unit 210 Dividing unit 220 Screen data input unit 230 Storage unit 240 First reading unit 250 Second reading unit 260 Synchronization signal input unit 270 Delay Part 280 first output part 290 second output part

Claims (1)

The first display,
A second display,
A display controller for sending image data obtained by combining two screen image data related to the screen display of the first display and the second display, and a reference clock and a synchronization signal for controlling the display of the image data;
A storage unit that stores the image data output from the display controller, a frequency dividing unit that generates a divided frequency obtained by dividing the reference clock by a half frequency, and the storage unit that stores the frequency Of the image data, a first reading unit that reads first image data to be output to the first display at the divided frequency, and the first image data read by the first reading unit. A first output unit that outputs to the first display together with the synchronization signal; and second image data to be output to the second display among the image data stored in the storage unit. A second reading unit that reads the divided frequency after the reading unit, a delay unit that delays the synchronization signal output from the display controller, and a second reading unit that reads the synchronization signal. A screen divider having a second output section for outputting the second image data to the second display with a predetermined time delay to the synchronizing signal in the reference clock and the delay unit of the divided frequency,
A two-screen display output system comprising:

Images