Display control device
First Claim
1. A display control device by which data stored in a video memory is displayed on the basis of a display control signals output from a CRT control device, the display control device comprising:
- dual port memory means that allows data read and write operations to be executed simultaneously and that has a capacity to store at least one screen of first data to be displayed; and
display control means for executing in parallel a first operation in which second data corresponding to an upper region of a display are retrieved from the first data stored in the video memory and sequentially output to said upper region of the display, a second operation in which the second data corresponding to the upper region of the display are sequentially stored in the dual port memory means and a third operation in which third data corresponding to a lower region of the display stored in the dual port memory means are sequentially output to said lower region of the display, for executing in parallel a fourth operation in which said third data corresponding to the lower region of the display are retrieved from the first data stored in the video memory and sequentially output to the lower region of the display, a fifth operation in which the third data corresponding to the lower region of the display are sequentially stored in the dual port memory means and a sixth operation in which fourth data corresponding to the upper region of the display stored in the dual port memory means are sequentially output to the upper region of the display and for alternately executing, in response to the display control signals, a first sequence comprised of the first to third operations and a second sequence comprised of the fourth to sixth operations.
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Accused Products
Abstract
A display control device for displaying data stored in a video memory on a flat display such as an EL or liquid crystal display on the basis of display control signals output from a CRT control device, which comprises a memory means that allows data read and write operations to be executed simultaneously and that has a capacity to store at least one screen of display data for display on the flat display and display control means for alternately executing, in accordance with the display control signals, a first operation in which data corresponding to an upper half of the display screen are retrieved from the data stored in the video memory and sequentially output to an upper region of the display, data corresponding to the upper half of the display screen are sequentially stored in the memory means, and data corresponding to a lower half of the display screen stored in the memory means are sequentially output to a lower region of the display, and a second operation in which data corresponding to the lower half of the display screen are retrieved from the data stored in the video memory and sequentially output to the lower region of the display, data corresponding to the lower half of the display screen are sequentially stored in the memory means, and data corresponding to the upper half of the display screen stored in the memory means are sequentially output to the upper region of the display
22 Citations
3 Claims
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1. A display control device by which data stored in a video memory is displayed on the basis of a display control signals output from a CRT control device, the display control device comprising:
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dual port memory means that allows data read and write operations to be executed simultaneously and that has a capacity to store at least one screen of first data to be displayed; and display control means for executing in parallel a first operation in which second data corresponding to an upper region of a display are retrieved from the first data stored in the video memory and sequentially output to said upper region of the display, a second operation in which the second data corresponding to the upper region of the display are sequentially stored in the dual port memory means and a third operation in which third data corresponding to a lower region of the display stored in the dual port memory means are sequentially output to said lower region of the display, for executing in parallel a fourth operation in which said third data corresponding to the lower region of the display are retrieved from the first data stored in the video memory and sequentially output to the lower region of the display, a fifth operation in which the third data corresponding to the lower region of the display are sequentially stored in the dual port memory means and a sixth operation in which fourth data corresponding to the upper region of the display stored in the dual port memory means are sequentially output to the upper region of the display and for alternately executing, in response to the display control signals, a first sequence comprised of the first to third operations and a second sequence comprised of the fourth to sixth operations. - View Dependent Claims (2)
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3. A display control device by which display data stored in a video memory is displayed on the basis of display control signals output from a CRT control device, wherein a display screen is partitioned into n partitions (n≧
- 3) in a vertical direction, the display control device comprising;
(n-1) dual port memory means that allow data read and write operations to be executed simultaneously and that have a capacity to store at least one screen of data to be displayed on the display; read/write control means for performing sequential common input of the data stored in the video memory to the (n-1) dual port memory means and for performing sequential cyclic read operations on the stored data using, as respective initial addresses, addresses each shifted to a degree equivalent to the address corresponding to data for (1/n) of the screen of the display from the (n-1) dual port memory means; and nth data selection means for alternately selecting, in a specified order, data read from the (n-1) dual port memory means and data retrieved from stored data in the video memory and for outputting in parallel the selected data to the respective partitioned regions of the display; and
, wherein each of the dual port memory means has a write address clock terminal, a read address clock terminal, a write address reset terminal and a read address reset terminal, and when a write address and a read address are updated as incremented by one in synchronism with a specified clock signal commonly input to the both of the clock terminals and when a reset signal is input to the write address reset terminal and the read address reset terminal, the dual port memory means initializes the write address and the read address on a memory region corresponding to a first scanning line of an upper screen of the display and wherein the device further comprises reset signal output means for commonly outputting the reset signal to the write address reset terminal of the respective dual port memory means each time output of data corresponding to an upper region of the display is started from the video memory, for previously setting an order of outputting the reset signal to each read address reset terminal of the (n-1) dual port memory means and, for intermittently and switchingly outputting the reset signal to the read address reset terminal of the dual port memory means in accordance with the set order each time the output of the data corresponding to the (1/n) screen of the display screen is completed from the video memory.
- 3) in a vertical direction, the display control device comprising;
Specification