Multi-plane page mode video memory controller
First Claim
1. A page mode memory controller for accessing a dynamic random access memory (RAM), comprising:
- means for accessing a selected memory row address;
means for latching said selected memory row address during a memory access interval;
means for providing a selected most significant (MS) memory column address portion;
means for providing a selected least significant (LS) memory column address portion;
means for combining said MS and said LS memory column address portions and for periodically accessing a corresponding memory column address during said memory access interval; and
a counter for sequentially incrementing said LS memory column address portion, in coordination with said periodic memory column address access, wherein a plurality of memory column addresses are accessed during said memory access interval, locating a plurality of corresponding sequential memory pages.
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Accused Products
Abstract
A page mode memory controller for a multi-plane color video display providing three bits/pixel corresponding to three page partitioning in each of sixteen 64K dynamic RAMs is described. The three bits/pixel are routed to a color lookup table to provide a choice of eight colors from a palette of 64 colors. Graphic display information is combined with alphanumeric video information on a pixel-by-pixel basis. The combined graphic/alphanumeric information is then converted from a digital signal to an analog signal. Page mode reads access three color planes for video display cycles using a counter for the two least significant memory column address bits. To create the displayed image, vectors are drawn three times, once at each plane.
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Citations
21 Claims
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1. A page mode memory controller for accessing a dynamic random access memory (RAM), comprising:
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means for accessing a selected memory row address; means for latching said selected memory row address during a memory access interval; means for providing a selected most significant (MS) memory column address portion; means for providing a selected least significant (LS) memory column address portion; means for combining said MS and said LS memory column address portions and for periodically accessing a corresponding memory column address during said memory access interval; and a counter for sequentially incrementing said LS memory column address portion, in coordination with said periodic memory column address access, wherein a plurality of memory column addresses are accessed during said memory access interval, locating a plurality of corresponding sequential memory pages. - View Dependent Claims (2, 3)
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4. In a multi-plane video graphic display, a page mode memory controller for accessng a dynamic random access memory (RAM) image memory array, comprising:
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a graphics controller for generating in sequence; (a) a memory row address signal; (b) a memory row strobe signal, wherein said address signal is latched into each memory element in said image memory array during a memory access period; and
thereafter(c) a most significant (MS) portion of a memory column address signal; a counter for generating a least significant (LS) portion of a memory column address signal; means for combining said MS portion and said LS portion of said memory column address signal; means for generating a memory column strobe signal at spaced intervals during said memory access period after generation of said memory row strobe signal; and means for sequentially incrementing said counter coincident with each generation of said memory column strobe signal, wherein a plurality of sequential image memory array pages are accessed during said memory access period, each page corresponding to one of said video display planes. - View Dependent Claims (5, 6, 7, 8, 9, 10, 11, 12)
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13. A method for accessing a dynamic random access memory (RAM), comprising:
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accessng a selected memory row address; latching said selected memory row address during a memory access interval; providing a selected most significant (MS) memory column address portion; providing a selected least significant (LS) memory column address portion; combining said selected MS and LS memory column address portions; periodically accessing a memory column address corresponding to said combined MS and LS memory column address portions during said memory access interval; and sequentially incrementing said LS address portion in coordination with said periodic memory column address access, wherein a plurality of memory column addresses are accessed during said memory access interval, locating a plurality of corresponding sequential memory pages. - View Dependent Claims (14)
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15. In a multi-plane video graphics display, a method for accessing a dynamic random access memory (RAM) image memory array, comprising:
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generating a memory row address signal; generating a memory strobe signal, wherein said address signal is latched into each memory element in said image memory array during a memory access period; generating a most significant (MS) portion of a memory column address; generating a least significant (LS) portion of a memory column address; combining said MS portion and said LS portion of said memory column address signal; generating a memory column strobe signal at spaced intervals during said memory access period after generation of said memory row strobe signal; and sequentially incrementing said LS memory column address signal portion coincident with each generation of said memory column strobe signal, wherein a plurality of sequential image memory array pages are accessed during said memory access period, each page corresponding to one of said video display planes. - View Dependent Claims (16, 17, 18, 19)
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20. In a multi-plane video graphics display, a method for accessing a dynamic random access memory (RAM) image memory array, comprising:
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generating a memory row address signal; latching said memory row address signal into said memory array with a memory row address strobe signal; removing said memory row address signal; generating a first memory column address strobe signal; generating a most significant portion (MS) of a memory column address signal; generating a least significant (LS) portion of a memory column address signal; combining said MS and said LS portions of said memory column address signal; accessing a first memory array location defined by an intersection of said memory row and column addresses; storing data contained at said memory array location in a buffer; removing said first memory column address strobe signal; incrementing said LS portion of said row address signal; generating a second memory column address strobe signal; accessing a second memory location defined by an intersection of said memory row and incremented column addresses; removing said second memory column address strobe signal; and serially shifting the data stored in said buffer from said buffer while simultaneously shifting data from said second memory location, to form two bit streams corresponding to a plurality of sequential display pixel locations having color or intensity attributes selected by the combined, multiple bit stream data. - View Dependent Claims (21)
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Specification