Gerbil wheel memory
First Claim
Patent Images
1. A display memory apparatus for use with a graphic display system, which avoids the simultaneous reading from and writing to a single memory location, comprising;
- a memory means for storing data wherein the memory means is partitioned into two frames of memory, each of the frames for storing data for a single display screen, and wherein the frames are each partitioned into a plurality of subframes;
a memory controller means coupled to the memory means by a first communication bus and a second communication bus, the memory controller means further coupled to the graphic display system by a write communication bus and a read communication bus, the memory controller means for controlling a transfer of data between the graphic display system and the memory means where the graphic display system has a read rate and a write rate which are not integer multiples of one another, the memory controller means controls the transfer of data by directing the transfer of data to assure that the data is not read from a subframe which is currently being written to.
1 Assignment
0 Petitions
Accused Products
Abstract
A display memory system consisting of a controller and a display memory that has a read display memory cycle time that is a non-integer multiple of the write display memory update rate. The display memory being partitioned into two frames of display memory with each frame having a plurality of subframes. The controller consisting of a read display memory decoder, a read display memory next subframe generator a read display memory latch and consisting of a write display memory decoder, a write display memory next subframe generator and write display memory latch.
71 Citations
27 Claims
-
1. A display memory apparatus for use with a graphic display system, which avoids the simultaneous reading from and writing to a single memory location, comprising;
-
a memory means for storing data wherein the memory means is partitioned into two frames of memory, each of the frames for storing data for a single display screen, and wherein the frames are each partitioned into a plurality of subframes; a memory controller means coupled to the memory means by a first communication bus and a second communication bus, the memory controller means further coupled to the graphic display system by a write communication bus and a read communication bus, the memory controller means for controlling a transfer of data between the graphic display system and the memory means where the graphic display system has a read rate and a write rate which are not integer multiples of one another, the memory controller means controls the transfer of data by directing the transfer of data to assure that the data is not read from a subframe which is currently being written to. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A display memory apparatus for use with a graphic display system, which avoids the simultaneous reading from and writing to a single memory location,
a memory means for storing data having a first addressing port, a second addressing port, a first data port, and a second data port, wherein the memory means is partitioned into a plurality of frames of memory and each frame is partitioned into a plurality of subframes; a memory controller means having a write addressing port for receiving addressing signals from the graphic display system, a write data port for receiving data from the graphic display system, a read addressing port for receiving read addressing signals from the graphic display system, a read data port for transmitting data to the graphic display system, an input address port connected to the first addressing port for transmitting address signals to the memory means, an input data port connected to the first data port for transmitting data to the memory means, an output address port connected to the second addressing port for transmitting address signals to the memory means, and an output data port connected to the second data port for receiving data from the memory means, the memory controller means for receiving write address signals on the write address port and producing an input address signal on the input address port which identifies a specific frame and a specific subframe within the memory means to which the write data signal is to be stored, the memory controller means also for receiving read address signals on the read address port and producing an output address signal on the output address port which identifies a specific frame and a specific subframe within the memory means from which data is to be retrieved, wherein the memory controller means will control the output address signals so as to assure that the input data will be written to and the output data will be read from different subframes. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
-
23. A display memory system for use with a graphic display system, comprising
a memory means for storing data having an input addressing port, an input data port, output addressing port, and an output data port, wherein the memory means is partitioned into a first frame of memory and a second frame of memory and wherein the first frame of memory is partitioned into a first subframe, a second subframe, a third subframe, and a fourth subframe, and the second frame of memory is partitioned into a fifth subframe, a sixth subframe, a seventh subframe and an eighth subframe; - and
a memory control means having a read addressing port for receiving read addressing signals from the graphic display system, a read data port for transmitting data to the graphic display system, a write addressing port for receiving write addressing signals from the graphic display system, a write data port for receiving data from the graphic display system, the memory control means further having a control means input address port connected to the memory means input address port for transmitting an input address signal to the memory means, a control means input data port connected to the memory means input data port for transmitting data to the memory means, a control means output address port connected to the memory means output address port for transmitting an output address signal to the memory means, and a control means output data port connected to the memory means output data port for receiving data from the memory means, the memory controller means for controlling a transfer of data to and from the memory means such that data can be written to the memory means and read from the memory means simultaneously and the memory controller further for assuring that data is not written to a subframe which data is concurrently being read from. - View Dependent Claims (24, 25, 26)
- and
-
27. A process for controlling the storage and retrieval of data from a memory wherein the memory is partitioned into two frames of memory and each frame is partitioned into a plurality of subframes, comprising the steps of:
-
a. writing data to the frames of memory wherein each frame is alternately written and wherein each frame is written to by sequentially writing to each subframe at a writing rate; b. reading data from the frame of memory which is not being written to, wherein the data is read at a reading rate which is not equal to nor an integral multiple of the writing rate and wherein each frame is read by sequentially reading each subframe within that frame; c. checking to determine if any subframe in the frame of memory which was not last read from will be written to during an upcoming reading cycle at an identical point in time that subframe could be read from; d. reading from the frame of memory which was not last read from if no subframe within that frame will be written to at the same time that subframe could be read; and e. reading from the frame of memory last read from if any subframe in the frame last read from will be written to at the same time that frame could be read.
-
Specification