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US5802579A
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System and method for simultaneously reading and writing data in a random access memory
Assignee: The AT&T MVPD Group LLC
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Filing: 1996-05-16
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Granted: 1998-09-01
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Expires: 2016-05-16
Abstract
Abstract A system (10) and method for providing simultaneous data reading and writing for a random access memory (18) include storing new data (14) and a corresponding new data address (26), comparing the new data address to a current read address (32), and substituting (38) the new data for the data at the current read address at the output (38) while simultaneously writing the new data into the memory (18). The system and method are particularly suited for application in space-based communication satellites which utilize continuous memory read accesses since the invention provides the functionality of a dual-ported RAM while being implementable with fewer gates and less complex control circuitry to provide reduced power consumption.
Inventors
- 👤 Philip D. Crary
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:36
CPC Classifications
G; G11; G11C; G11C8/00; G11C7/00; G11C7/10; G11C7/1078
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
97 words
A method for providing simultaneous modification and retrieval of data using a single-ported memory having a plurality of locations each having a corresponding address, the method comprising: storing a modification address corresponding to one of the plurality of locations; storing modification data corresponding to the modification address at a location other than the plurality of locations; receiving a request to retrieve stored data from the memory at the modification address; retrieving the modification data from the location other than the plurality of locations; and substantially simultaneously storing the modification data in the memory at the modification address.
Claim 2
Independent Claim
97 words
A method for providing simultaneous modification and retrieval of data using a single-ported memory having a plurality of locations each having a corresponding address, the method comprising: storing a modification address corresponding to one of the plurality of locations; storing modification data corresponding to the modification address at a location other than the plurality of locations; receiving a request to retrieve stored data from the memory at the modification address; retrieving the modification data from the location other than the plurality of locations; and substantially simultaneously storing the modification data in the memory at the modification address.
Claim 3
Dependent Claim
22 words
The method of claim 1 wherein storing a modification address comprises storing a modification address in a register external to the memory.
Claim 4
Dependent Claim
23 words
The method of claim 1 wherein receiving comprises receiving a request to retrieve data stored at a location corresponding to the modification address.
Claim 5
Independent Claim
164 words
A method for providing modification and retrieval of data stored in a single-ported random access memory at a plurality of locations each having a corresponding address, the method comprising: storing a first address corresponding to one of the plurality of locations of the single-ported random access memory in a first register; storing modification data associated with the first address in a second register; receiving a request to retrieve stored data from the random access memory at a second address corresponding to one of the plurality of locations; comparing the second address to the first address; retrieving the stored data from the random access memory when the comparing step indicates that the first address does not correspond to the second address; and retrieving the modification data from the second register and storing the modification data from the second register and substantially simultaneously storing the modification data in the random access memory when the comparing step indicates that the first address corresponds to the second address.
Claim 6
Independent Claim
164 words
A method for providing modification and retrieval of data stored in a single-ported random access memory at a plurality of locations each having a corresponding address, the method comprising: storing a first address corresponding to one of the plurality of locations of the single-ported random access memory in a first register; storing modification data associated with the first address in a second register; receiving a request to retrieve stored data from the random access memory at a second address corresponding to one of the plurality of locations; comparing the second address to the first address; retrieving the stored data from the random access memory when the comparing step indicates that the first address does not correspond to the second address; and retrieving the modification data from the second register and storing the modification data from the second register and substantially simultaneously storing the modification data in the random access memory when the comparing step indicates that the first address corresponds to the second address.
Claim 7
Dependent Claim
25 words
The method of claim 4 wherein comparing comprises determining when the first and second addresses correspond to the same one of the plurality of locations.
Claim 8
Dependent Claim
17 words
The method of claim 5 wherein comparing comprises determining when the first and second addresses are identical.
Claim 9
Dependent Claim
22 words
The method of claim 4 wherein the steps of retrieving the stored data and retrieving the modification data are performed mutually exclusively.
Claim 10
Dependent Claim
26 words
The method of claim 4 further comprising: mutually exclusively selecting either the stored data or the modification data for output based on the step of comparing.
Claim 11
Dependent Claim
32 words
The method of claim 4 wherein retrieving the modification data from the first register and storing the modification data in the random access memory are performed during a single memory access cycle.
Claim 12
Independent Claim
170 words
A system for providing substantially simultaneous modification and retrieval of data stored in a single-ported random access memory at a plurality of locations each having an associated address, the system comprising: a random access memory; a first register in communication with the random access memory for storage of modification data; a second register for storage of a modification data address associated with the modification data; logic in communication with the second register and the random access memory for determining when a retrieval request corresponds to the modification data address; and a multiplexer in communication with the random access memory, the logic, and the first register for selecting one of the modification data and the data stored in the random access memory for output based on the determination of the logic, wherein the logic causes the multiplexer to select the first register for output when a read request corresponding to the modification data address is received while substantially simultaneously causing the modification data to be stored in the random access memory.
Claim 13
Independent Claim
170 words
A system for providing substantially simultaneous modification and retrieval of data stored in a single-ported random access memory at a plurality of locations each having an associated address, the system comprising: a random access memory; a first register in communication with the random access memory for storage of modification data; a second register for storage of a modification data address associated with the modification data; logic in communication with the second register and the random access memory for determining when a retrieval request corresponds to the modification data address; and a multiplexer in communication with the random access memory, the logic, and the first register for selecting one of the modification data and the data stored in the random access memory for output based on the determination of the logic, wherein the logic causes the multiplexer to select the first register for output when a read request corresponding to the modification data address is received while substantially simultaneously causing the modification data to be stored in the random access memory.
Claim 14
Dependent Claim
16 words
The system of claim 10 wherein the random access memory is a single-ported random access memory.
Claim 15
Dependent Claim
29 words
The system of claim 11 further comprising an address generator in communication with the logic and the random access memory for providing an address associated with the retrieval request.
Claim 16
Dependent Claim
25 words
The system of claim 10 wherein the random access memory, the first and second registers, and the logic are implemented in a single integrated circuit.
Claim 17
Dependent Claim
19 words
The system of claim 10 wherein the first and second registers are located external to the random access memory.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-31 | 2002-03-02 | 2002-09-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-31 | 2006-03-02 | 2006-09-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-31 | 2010-03-02 | 2010-09-01 | $7700.00 | Window Closed / Lapsed |