JPS643272B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a display device used as a console or terminal device of a computer system, and more particularly to an improvement in the interface between a control section and a display section. In display devices that use a CRT (cathode ray tube) unit for the display section (display/input section), unlike general television receivers, the interface method between the control section and the display section is as follows. is normal. That is, the control section does not send the video signal and the synchronization signal to the display section in the form of a composite video signal, but separates them into separate signals and sends them. In other words, in the case of a monochrome display, one level-modulated dot signal is used for brightness modulation, and in the case of a color display, three dot signals corresponding to the three primary colors of red, green, and blue are used as video signals on the display section. send to Further, the horizontal synchronization signal and the vertical synchronization signal are separated and sent to the display section. Such an interface system has the advantage of reducing the cost of the display unit because it eliminates the need for a sync separation circuit, brightness modulation circuit, and color separation circuit in the CRT unit. However, in a configuration in which the control section and the display section are physically installed at a considerable distance, the above-mentioned conventional interface system has the following problems. First, since there are a large number of interface cables, the workability of installation work is poor and the appearance is also undesirable. Furthermore, in the case of monochrome display, the dot signals are level modulated, so inexpensive digital line driver ICs and receiver ICs cannot be used. In the case of color display, the dot signal is divided into three lines, each requiring an expensive coaxial cable. As described above, the conventional interface system has several drawbacks such as an increase in the cost of the interface when the control section and the display section are installed at a relatively long distance apart. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a display that can realize an interface at low cost when a control section and a display section are installed apart from each other, and that can solve the above-mentioned installation and appearance problems. The goal is to provide equipment. However, in the display device according to the present invention, only one dot signal that is not level-modulated is sent from the control section to the display section as a video signal, and color control (in the case of color display) or brightness control (in the case of monochrome display) is performed. ), the display control signal and synchronization signal for synchronization control are time-division synthesized and sent, and the display unit separates and extracts the display control signal and synchronization signal from the time-division synthesis signal, thereby performing color control. Or display dot signals while controlling brightness and synchronization. A video signal containing high frequency components is a dot signal 1.
The other time-division synthesized signals have low repetition frequencies. Therefore, even in the case of color display, only one expensive coaxial cable is required for the dot signal. Other signals can be transmitted using some signal lines of a multicore cable prepared for the display section (generally, an input section such as a keyboard is also integrated) and the control section interface. Note that a signal for separating the time-division combined signals on the display side is sent from the control unit to the display unit (however, this signal can also be generated on the display side from a synchronization signal, etc.). Signals can also be transmitted using some of the multicore cables mentioned above. As described above, according to the present invention, the number of interface cables between the control section and the display section can be reduced, and the cost can also be reduced. Furthermore, since the dot signal is transmitted without level modulation, inexpensive digital line driver ICs and receiver ICs can be used. Therefore, the interface can be realized at low cost. Hereinafter, one embodiment will be described in detail. FIG. 1 is a block diagram of a color display device which is an embodiment of the present invention. In this example, the control section CTRL and the display section keyboard section
The DSP/KB is connected by a coaxial cable 7 and a multicore cable 8. The multicore cable 8 is configured to transmit a signal K related to the keyboard 20 and the panel 21, time-division composite signals RH, GV, BX, and a selection signal S, which will be described later, and the coaxial cable 7 is configured to transmit a dot signal D. . In FIG. 1, driver circuits and receiver circuits at both ends of the cables 7 and 8 are omitted. Display memory 2 is connected via the bus BUS.
Data inputted from the keyboard 20 via the input/output controller 22 and data inputted/outputted to other devices (not shown) are stored, and are synchronously read out at timing T from the timing generator 1. This read data DT is supplied to the character generator 3 and decoder 4. Character generator 3 is read data
A dot signal D is created using the DT and the timing RT from the timing generator 1, and is output to the coaxial cable 7. Decoder 4 is read data DT
is decoded at timing T, and color control signals R (red), G (green), and B (blue) specifying display colors are output to the selector 6. The decoder 5 decodes the timing T from the timing generator 1,
A horizontal synchronizing signal H, a vertical synchronizing signal V and a selection signal S are output to the selector 6. The selector 6 switches the color control signals R, G, B or the synchronization signals H, V according to the polarity of the selection signal S to produce time-division composite signals RH, GV, BX, and outputs them to the multicore cable 8. A selection signal S is also output to the same cable 8. Switching (time division synthesis) of the signals of the selector 6 is performed as shown in the following table.

[Table] Note that since there is no particular signal X to be added to the input _C1 of the selector 6, in this example, an X="0" signal is applied. If there is another signal to be transmitted, that signal may be added to the _C1 input of the selector 6 as an X signal. On the other hand, on the display/keyboard DSP/KB side,
The selector 9 inputs the selection signal S and the time-division composite signals RH, GV, and BX transmitted through the multi-core cable 8, and performs color control from the time-division composite signals RH, GV, and BX depending on the polarity of the selection signal S. Signals R, G, B and synchronization signals H, V are separated and output. That is, the signals are separated as shown in the following table.

[Table] In the gate circuit 10, the dot signal D transmitted through the coaxial cable 7 is gated by the color control signals R, G, and B from the selector 9, and is sent to the CRT unit as three primary color dot signals RD, GD, and BD. 1
Enter 1. Here, the three primary color dot signals RD,
GD and BD are AND signals of the dot signal D and the color control signals R, G, and B, respectively, and are expressed by the following equation. RD=R.D GD=G.D BD=B.D The CRT unit 11 also receives a horizontal synchronization signal H and a vertical synchronization signal V from the selector 9. The time chart in FIG. 2 shows an example of the time-division synthesis operation of each of the signals. In the figure, T=0, 1, 2, . . . each indicate the display time of one character, and H _n indicates one scanning line period. One scanning line period is a period from T=0 to T= _N3 , of which T=0 to N1 is a character display period, and N2 to N3 is a horizontal retrace time. V _n is the vertical retrace time and lasts for multiple scan line periods. The horizontal synchronization signal H is generated within the horizontal retrace period H _n and the vertical synchronization signal V is generated during the vertical retrace time V _n . The color control signals R, G, and B differ depending on the display data, but in the example of FIG. 2, they are generated as follows. That is, in the scanning line period H _n , the R signal is generated during the period T = 0 to 3, the G signal is generated during the period T = 4 to 6, and the B signal is generated during the period T = 7 to 10. (becomes “1”). Further, the selection signal S is "1" during the horizontal and vertical retrace periods, but becomes "0" during the display period (T=0 to _N1 ). The operations of the selectors 6 and 9 are as shown in Tables 1 and 2, and their explanation will be omitted. Although the above embodiment is a color display device, a monochrome display device may be configured as follows. First, the decoder 4 decodes the read data DT from the display memory 2 and outputs a brightness control signal to the selector 6. A selector 6 time-divisionally synthesizes the synchronization signals H, V and the brightness control signal, and a selector 9 synthesizes the synchronization signals H, V from the time-division synthesis signal.
and the brightness control signal. Gate circuit 10
is replaced with a level conversion circuit, and the level conversion circuit level-modulates the dot signal D using the separated luminance control signal and inputs it to the CRT unit 11. Needless to say, the separated synchronization signal H,
V is also input to the CRT unit 11. As described above, the present invention can reduce the cost of the interface between the control section and the display section, and because the number of interface cables is reduced, the workability and appearance of installation work can be improved. , many effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a diagram showing a time chart for explaining the operation of the embodiment. 1... Timing generator, 2... Display memory, 3... Character generator,
4, 5...Decoder, 6,9...Selector, 7...
...Coaxial cable, 8...Multi-core cable, 10...
Gate circuit, 11... CRT unit, 20...
Keyboard, 21... Panel, 22... Input/output controller.

Claims (1)

[Claims] 1 Equipped with a control section and a display section, from the control section to the display section, only one dot signal that is not level modulated is sent as a video signal, and display control signals and synchronization control for color control, brightness control, etc. The display section separates and extracts the display control signal and the synchronization signal from the time-division-synthesized and sent signals, and performs synchronization control using the separated synchronization signals. A display device configured to display the dot signal while controlling color or brightness using a separate display control signal.